CEP 08014 TeraRecon AquariusNET server for 3D image

Transcription

Evaluation report
TeraRecon AquariusNET server for 3D
image reconstruction
CEP 08014
August 2008
Contents
2
Executive summary .................................................................................. 3
Introduction............................................................................................... 5
Product description................................................................................. 10
Methods.................................................................................................. 30
Technical performance........................................................................... 31
Operational considerations..................................................................... 33
Economic considerations ....................................................................... 36
Purchasing ............................................................................................. 41
Conclusion.............................................................................................. 42
Acknowledgements ................................................................................ 43
Glossary ................................................................................................. 44
References ............................................................................................. 46
Appendix 1. Supplier contact details ...................................................... 47
Appendix 2. AquariusNET update .......................................................... 48
Author and report information................................................................. 49
CEP 08014 August 2008
Executive summary
3
The product
The TeraRecon AquariusNET system provides three dimensional (3D) functions on volume
image data sets using a dedicated server. A dedicated graphics processor performs the
reconstruction and graphic rendering and image data are streamed to the client machine
across the network. As the processor-intensive functions are performed on the server, the
user can view the images on a relatively low powered PC. The process is interactive and
transparent to the user, as though the tasks are being performed locally. The client software
runs on a personal computer (PC) running Microsoft Windows 2000 or Windows XP
operating system and Internet Explorer version 6 with a recommended minimum
specification of Pentium II central processing unit, 256 Megabytes random access memory, a
video card capable of displaying 24 bit colour depth and a 1024 x 768 pixel resolution
display.
The product allows the user to perform advanced visualisation techniques on DICOM image
volume data sets produced from CT and MRI scans, including multi-planar reformats (MPR),
curved planar reformats (CPR), maximum intensity projections (MIP) and volume rendering.
Vessel analysis tools with centre line extraction are provided along with the facility to analyse
multi-phase studies and display image merge of two modalities. The use of segmentation
algorithms on the dataset according to pre-determined rules performs routine segmentation
tasks automatically, eg rib cage removal from a CT scan of the heart.
AquariusNET version 1.7 was evaluated. Upgrades have been released subsequently.
Field of use
AquariusNET can be used where advanced visualisation techniques may be required on
volume data sets. In imaging departments it allows the reporting of scans to take place at a
user’s desktop or reporting workstation rather than using the dedicated modality workstation.
It can also be used for interactive reconstructions at multi disciplinary team meetings.
Departments outside the imaging department may interactively review anatomy using the
rendering and segmentation tools. Review of complex fractures and visualisation of vascular
structures can be used to plan surgical procedures outside the imaging department by the
surgeons in the office, clinic or operating theatre.
The use of a thin client system, with appropriate security measures, facilitates teleradiology,
extending the ability to view scans and images to users outside the hospital.
Evaluation method
An AquariusNET VLE server was installed by TeraRecon at the evaluation site as a local
server.
The server hardware was benchmarked to assess its relative speed. Various large volume
studies were loaded from the AquariusNET server and the time taken to display the first
volume rendered image was recorded.
Executive summary
4
Power consumption of the server was compared with that of standard PCs.
Using studies from a range of modalities, the images were viewed and the imaging tools
tested. The tools were assessed for functionality, ease of use and accuracy.
CEP verdict
AquariusNET 1.7 provides 3D tools which can extend the functions of existing PACS
workstations, and offers access to these tools to users outside the imaging department. It is
able to access studies from various sources. Not only can studies be pushed to the server by
the modality and retrieved from a modality or PACS archive but studies may also be
imported to the AquariusNET server from the user’s client machine. The tools provided are
straightforward to use and the manual helpful and clear.
The AquariusNET implementation of thin-client technology works well and no problems were
encountered with the server during the testing period. It was found that on older client PCs,
with the minimum recommended specifications, the response was noticeably sluggish,
especially when using volume rendering tools. On newer machines, the response was
acceptable.
The addition of volume imaging to the PACS workstation allows the reporting of volume
studies such as CT and MRI to be incorporated into the general reporting workflow. The
ability to use volume tools, in particular MPR and MIPS, without recourse to the modality
workstation, and to review other images relating to the scan being reviewed, can improve the
reporting workflow. Integrating AquariusNET 1.7 into the departmental PACS/RIS can bring
these benefits, and the flexibility of the thin client architecture gives access to the advanced
tools across the network to users in other departments using a standard PC.
Introduction
5
The TeraRecon AquariusNET system offers interactive three dimensional (3D) image
management and distribution through standard (‘thin-client’) personal computers (PCs),
rather than dedicated diagnostic imaging workstations.
The AquariusNET uses a server to perform the 3D functions and distribute the images. It
also performs pre-set segmentation algorithms on the dataset according to pre-determined
rules, for example rib cage removal from a CT scan of the heart
A license fee for unlimited client use is included, so any PC can operate as a client, without
incurring additional costs. This may facilitate workflow, helping hospitals to achieve
government waiting time targets.
Three dimensional (3D) imaging
‘3D imaging’ refers to software that allows the user to create different views from volume
data sets. In radiology, such data sets are those images acquired from cross-sectional
imaging modalities, such as computed tomography (CT) and magnetic resonance imaging
(MRI).
Common procedures used to create such views are:
•
multi planar-reformat, (MPR) - where the original image data is reformatted along a
curved or linear plane;
•
maximum intensity projection (MIP) - a view that emphasises maximum values of
intensity in the image pixels or voxels;
•
virtual endoscopy - replicates a view as if examined through an endoscope;
•
3D visualisation - where computer graphic techniques create a single view of the
entire volume;
These techniques have been available for many years, but their clinical use has been limited
by the resolution of the cross-sectional image data and the need for dedicated workstations
to run the programs.
Recent developments in imaging modality technology, in particular CT scanning, have led to
improved resolution. The use of narrower slices may potentially result in thousands of
images. This has enabled changes in scanning technique: for example, CT sinuses may
previously have been acquired with both direct axial and coronal scans, but now the patient
need only be scanned axially with the coronal slices created by the reformatting tools. Tools
such as MPR and MIP give the user a valuable means to view non-axial images and aid the
navigation of these images.
3D imaging allows the user to display anatomy in a more pertinent form. For instance,
rendering a CT cerebral angiogram showing a cranial aneurysm can demonstrate the
anatomy and the relationships of the vessels in just one or two images.
Introduction
6
Application software has been developed for 3D imaging for use on a PC, either as standalone software or, more usefully, integrated into the PACS reporting workstation software. As
more imaging departments are using PACS for storage and reporting, cross-sectional image
data can be accessed from reporting workstations. Whilst most PACS reporting workstations
have the ability to view cross sectional images, they do not all have 3D functions. Having
integrated specialist 3D imaging tools allows the user to manipulate multi-slice images as
part of the reporting process and not have to interrupt the work flow in order to use a
specialist 3D imaging workstation to perform these tasks.
The manipulation and rendering of images requires computationally intensive methods to
produce the 3D images. A number of methods are employed to achieve acceptable
rendering and manipulation speeds:
•
use of high processing power. The processor on the PC is used to manipulate and
perform the rendering functions. Multi-core technology in processor design and the
increasing use of 64 bit software has resulted in powerful low cost machines
•
use of a dedicated graphics processor. This is a separate card on the server having
its own memory and a dedicated graphics processor for manipulating and rendering
the images. The resulting rendered images may be displayed on a standard graphics
card
•
high end graphic display cards. Cards developed for the computer games industry
have specialised graphic processors, these can be used on a PC to render and
display the image. They differ from the graphics processor above, in that the cards
have less built in memory than the dedicated processing card and the manipulation
and rendering is shared with the PC’s processor(s)
•
3D server. This model uses a dedicated 3D server that performs all the 3D processes
and distributes the resulting images to the user’s machine (the client). The client
machines need not be powerful or require as large amounts of memory, as the server
performs the intensive processing tasks.
AquariusNET
AquariusNET provides 3D functions using a dedicated server, with a dedicated graphics
processor, to perform the reconstruction and graphic rendering, and the image is streamed to
the client machine.
The core functions for 3D rendering are provided by the VolumePro™ graphics processing
card, a dedicated hardware board. The image data are stored in the card’s own memory.
These images are then streamed to the client over the network via web browser, resulting in
real time interactive 3D processing.
The graphic processing functions are performed by the AquariusNET server. The streaming
of data to and from the server is continuous and transparent to the user.
Introduction
7
The advantages of this method are that:
• as the CPU intensive work is performed on the server, the client machine does not
require a high specification in terms of processor type or memory
• the licensing for the client software is such that any number of users may use the
system, limited only by the memory on the card
• upgrades and software administration can be managed centrally
• the 3D tools can be used throughout the healthcare enterprise
• the full DICOM data set is only sent across the network once (to the AquariusNET
server). The image data sent by the server to the client are small having a small
impact on the network.
The disadvantages are that:
•
•
the server and associated hardware incur a high capital cost. This has to be
considered when compared to the cost of purchasing and/or upgrading individual
workstations with software.
should the AquariusNET server fail, the service is unavailable to all users, unless
there is a back-up server.
Image data flow in 3D imaging
The large data volumes generated by cross-sectional imaging modalities can mean that
when transferring the studies to a workstation, there may be an appreciable delay before the
full dataset is transferred to the workstation, due to the capacity of the network. A typical
example of the flow is illustrated in figure 1.
The images are sent to the PACS archive and also to the modality (usually CT or MR)
workstation for the advanced processing. If 3D imaging tools are available on the radiology
reporting workstations, then the full image dataset has to be sent to the workstation and in
some cases, depending on the network load and the network speed, the time taken for the
dataset to load becomes unacceptable.
Using the client server approach, the flow is changed in that the full dataset only needs to
flow across the network once to the AquariusNET server. Interactions between the client
machine and the server have a relatively small impact on the network (see figure 2).
Introduction
Figure 1. Typical image flow
8
Introduction
9
Figure 2. Image flow using AquariusNET
Figure 2. Image flow using AquariusNET
Product description
10
AquariusNET version 1.7
AquariusNET is part of TeraRecon’s iNtuition group of products, designed to provide volume
processing tools (3D) that integrate into the workflow of an imaging department.
AquariusNET 1.7 is a CE marked class IIb medical device and is available in a number of
different configurations. These are related to the number of images that can be stored in the
VolumePro™ (VP) board and the type of image storage either as standard hard disk storage
or Redundant Array of Inexpensive Disks (RAID). The main difference between the models is
in the amount of onboard VP memory there is available and the storage type. All models
support the main tools for MPR, MIP and volume rendering. The advanced pre-processing
server (APPS) tools such as automatic bone removal are only available with the VLE model.
Table 1. AquariusNET server specifications
Manufacturer &
Model
Dell PowerEdge 2900
Processor
2 x Quad core processors @1.86 GHz
Operating System
Microsoft Windows™ 2003 operating system
Storage
1.16 TB of RAID 5 Storage (0.876TB usable) Hot swap disks and
extra storage bay.
2.4 TB (1.8TB usable) storage for the Enterprise and VLE models
Table 2. AquariusNET configurations
Server model
Slice capacity
(largest single
series)
VolumePro™ boards /
memory
Server host
memory
AquariusNET Blue with
Std. Server Hardware
1,700 (1,700)
1 VP Board with 1 GB
1 GB
AquariusNET SE with
Std. Server Hardware
3,400 (3,400)
2 GB
AquariusNET VSE
6,800 (6,800)
2 GB
AquariusNET Standard
6,800 (3,400)
2 VP Boards with 2 GB
2 GB
AquariusNET VME
13,600 (6,800)
2 GB
AquariusNET Enterprise
13,600 (3,400)
4 GB
AquariusNET VLE
27,200 (6,800)
4 GB
Product description
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The AquariusNET server
The VLE model was supplied for the evaluation by TeraRecon, San Mateo, USA. The server
was supplied with a 15” monitor, keyboard and mouse, Microsoft Server 2003 64 operating
system and the AquariusNET software loaded and preconfigured (Figure 3).
Figure 3. The AquariusNET Server
The server has four principal functions, outlined below.
Image database
The server acts as a repository for images and stores the data sets locally on hard disk,
maintaining its own database of the studies stored.
AquariusNET imports studies from the PACS archive or the modality and also stores images
and studies on the AquariusNET server and to the PACS archive using DICOM services (CSTORE, C-MOVE, C-FIND, Storage SCP, Q/R, SCU/SCP).
So studies may be sent to the AquariusNET archive from the modality or the PACS archive
and the AquariusNET is able to search the modality or PACS archive and import the study.
Rendering
Rendering of the images is performed using VolumePro 1000, which is a special purpose
board that allows real-time 3D volume rendering of large data sets. The VolumePro 1000 is a
PCI card that uses dual application specific integrated circuits (ASICs), allowing it to sample
109 times per second. Each board can store up to 3.2 GB of memory for holding the
datasets. Up to 4 VolumePro PCI cards may be installed in a single server, giving a
maximum of 13GB of volume data equivalent to approximately 27,000 CT image slices.
Product description
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Advanced pre-processing
Volume data are processed and segmented according to customised rules set up in the
server administration. DICOM tag information is used to select those studies as appropriate
and the processing is automatically performed before displaying the image on the client
screen.
•
•
•
Bone removal – removes the bony skeleton from vascular images (eg CT leg
arteriography)
Rib cage removal – removes the ribs from the image
Couch top removal – removes the couch top from the image.
TeraRecon also offers additional pre-processing tools which were not evaluated:
•
•
parametric mapping – the server automatically analyses the breast MRI sequence
and colour-codes pixels based on the time-dependent behaviour of the pixels during
enhancement, defining possible lesions
Spherefinder – this highlights spherical objects in a pre-defined size range. The
software is available for both lung and colon CT.
Distributing the images
The images are streamed to the client machine using progressive streaming image
technology up to 15 frames per second over a 100 Mbit/s network. During interactive
manipulation of an image, such as rotating the rendered image, a 'ghost' image of the object
is displayed until the mouse button is released when the full image is displayed.
The server may be administered over the network using a web interface. Table 3 describes
the various administration tools available.
Product description
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Table 3. Server administration tools
Tool
Tool purpose
Download AquariusNET applications to
the client machine.
The conference viewer.
The AquariusNET thin client viewer.
AquariusNET thin client ActiveX – for viewing
AquariusNET generated reports on client machines
without the AquariusNET viewer.
Manage local & remote Application
Entities (AE)
Local AE’s are those on the server, while remote AE
refers to modality and PACS servers.
Account administration
Manage user accounts
Manage domains and domain users
Printer management
Job management
The server can send on images to remote hosts
using a job queue.
Pre-fetching. A pre-fetch job is created according to
the pre-fetch pattern and then the job is queued for
fetching.
Advanced processing. Filtering studies for the
advanced processing tools.
Workflow management
Managing DICOM tags and filters. DICOM tags are
used as a means of filtering studies for various tasks.
Auto assignment. Assigning the local AE to user
groups and then studies pushed to a local AE will be
assigned to a user group. A tag filters may be used to
associate with a user group. Auto filming.
Auto Pre fetch. Setting pattern matching rules to prefetch previous studies.
Schedule times for routing.
Advanced processing
Set-up and manage the tags that are used to initiate
the Advanced processing tools.
General tools
Display log information.
Managing image deletion from the server.
Assigning series to users.
Managing user series status.
Manual routing of series.
Anonymising series.
Server configuration
Product description
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The client machine
The minimum requirements for the client PC are shown in table 4.
Table 4. AquariusNET client machine minimum requirements
Operating system
Windows 2000, XP, Internet explorer 6
Processor
Pentium II or better
Memory
256 MB RAM
Video card
General purpose graphics Truecolor Display
Display matrix
1024 x 768 or greater
Networking
Standard network card ( 10 Mbit/s minimum, 100
Mbit/s preferred).
Selecting the study and series
The images may be sent to the server directly from the modality or they may be imported
from the PACS server or the modality. Images may also be imported into the AquariusNET
server from the client machine data storage device, for example CD/DVD, hard-drive or flash
storage.
Tools & functions
Tools may be selected either by clicking on the tools on the toolbar or right clicking the
mouse and selecting the tool from the context sensitive pop-up menu and the tool is applied
to the left mouse button if appropriate. The right mouse button is configured to pan the image
The icons used make the function clear and the selection process is straightforward.
Table 5. General tools and functions
Tool / function 2D
Comments
Window level and width
Window level and width may be altered using the mouse or onscreen controls.
Image zoom
Magnifies the image.
Pan
If the image is larger than the display area, this tool allows the user
to move the image around the display.
Multiple views
AquariusNET can view up to 4 series at a time.
Slice change
2 speeds for moving through the stack.
Series synchronisation
Synchronise the level of the images of two or more studies for
comparison.
Product description
Tool / function 2D
15
Comments
Display matrix
Allows the user to display images up to a 5x5 matrix on the screen.
Display pixel value
Displays the value represented by the pixel beneath the pointer. Eg
Hounsfield unit (HU) in CT, uptake value in nuclear medicine.
Measurements
Line (mm).
Annotation
Annotate the image and arrow.
Segment
Measures the length of an irregular shaped object.
Relative length
Compares two lines and the second line is given as a proportion of
the first.
Angle
Describes the angle.
Region of interest
Describes different shapes and displays the mean, maximum,
minimum and standard deviation of the values in the region and the
area in mm2.
Displays a rectangle/square.
Displays an ellipse/circle.
Displays irregular shaped object.
Rectangle
Ellipse
Polygon
Profile
This displays a graph showing the image pixel values along a line
drawn on the image by the user.
Cine
Displays the images in a series in rapid succession. The rate may
be adjusted and the images displayed forwards or backwards.
Invert greyscale
Inverts the greyscale by swapping light grey shades in the image for
dark grey shades and visa versa.
Colour
Displays five colour options.
Image rotate and flip
Rotate and/or flip the image from left to right using the tools on the
display.
Printing images
Prints to a DICOM or a printer.
Import
Import images from sources on the client machine such as CD or
flash memory.
Conference
Use the server to communicate and display studies.
CT presets
10 presets for window width & level that may be changed to an
individual’s preference.
Segmentation
Removes areas of volume rendered images.
Product description
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Table 6. Tools for advanced visualisation
Advanced visualisation tools
(3D)
Comments
Rotate
Rotates the volume rendered image using the mouse. The
rendered image can also be rotated by clicking on the
arrow keys.
Multi planar reformat (MPR)
Orthogonal views (Axial, Sagittal and Coronal) displayed
routinely.
Oblique reformat view.
Curved planar reformats (CPR)
Manual.
Automatic using centre line extraction tool.
Dental CPR.
Maximum intensity projection
Maximum IP, Minimum IP and RaySum – The application
averages the thickness of consecutive slices to smooth
the image.
Automated segmentation
Rib cage removal.
Bone removal.
Couch top removal.
(These tools are available in servers with APPS.)
4D viewing
Volume cine.
Batch reformatting
Axial and radial reformatting.
Saving images
May be saved to a local drive as DICOM, jpeg or BMP
format and AVI cine.
Volume tools
Adjust the size of the volume dataset.
Image fusion / overlay
Overlays images from 2 different modalities e.g. PET &
CT.
Virtual endoscopy view
A technique for volume rendering intra-luminal objects
such as the large bowel or the bronchus.
Scene
Saves the state of the 3D process.
AquariusNET makes extensive use of the mouse or other pointing device to select tools.
Tools may be selected from the main toolbar, which changes according to the study being
viewed, or by right-clicking to display a context sensitive menu.
Getting started
AquariusNET is started on the client machine by clicking the AquariusNET icon and after
entering a password the loading screen is populated with the patient data. If more than one
AquariusNET server is available an alternative IP address may be selected. If more than one
Product description
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monitor is available, selecting the multi-monitor option on the start-up panel extends the
desktop across the screens. Alternatively, it is possible to run more than one copy of the
AquariusNET application and have each running on its own screen, useful for comparing
different studies.
Loading images
The load screen (figure 4) allows the user to select the study for review. Images may be
selected by directly clicking the patient name or the selection may be narrowed by
configuring the search box, selected by clicking on the search button. The default database
is the AquariusNET server however, by selecting remote server a different database can be
selected, such as the CT or MRI database. A sub-set of the series may be chosen if
required. A small viewer displays the selected series and up to four series from one study
may be loaded for viewing.
Figure 4. Load study screen
Once a study is highlighted the user may also right-click to display a sub menu giving further
selection options including selecting all studies for the same patient, and tools for exporting
and deleting the study on the database and for anonymisation of the study.
Images may also be loaded onto the AquariusNET server from the client machine’s hard
drive, or from external media such as CD or USB memory stick. The AquariusNET can load
images as DICOM images or from a DICOM directory, however, the study must be in its own
folder.
Product description
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Selecting the scene button displays scenes which have been saved in the study. A scene is
‘snapshot’ of the volume imaging process. It records the status of the process and it is then
possible to continue working on the data from the point at which it was saved.
2D viewing
While AquariusNET is primarily for 3D visualisation from volume datasets such as CT and
MRI, it will display most DICOM images and the 2D view intelligently displays DICOM images
from a wide range of other modalities, adjusting the tools and views available according to
the modality.
Figure 5 shows a CT scan displayed on a 2x2 matrix. The matrix can display up to 5x5
images and double clicking on an image displays that single image enlarged. Window width
and level can be changed either with the mouse or using the sliders to the right. There are 9
preset level buttons which can all be easily customised for each modality and the settings
saved to the client machine. Not all tools are available for all modalities, for example the user
is not able to flip or rotate XA (angiography) or RF (fluoroscopy) images.
Figure 5. 2D screen
Figure 6 shows a cardiac catheterisation angiogram displaying all the views which may be
selected individually. Basic measurement and viewing tools may be used but there are no
advanced tools such as cardiac ejection fraction.
Product description
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Figure 6. Cardiac Angiography Screen
3D viewing
Figure 7 shows the default view when loading volume data. The four panels initially displayed
show the orthogonal (axial, coronal and Sagittal) MPR views with the top right panel
displaying the result of the reformat or render, the default view being a volume rendered
image.
The tool bar is similar to that for 2D viewing, except that the Window / Level button is
replaced by a rotate icon. Windowing may still be accessed by the right-click menu. Buttons
are available for selecting the advanced processing tools (bone, rib & couch top removal),
curved planar reformatting (CPR), and scene saving.
Tools are provided for rotating the volume rendered image. The six buttons labelled ‘A’,
P’.’H’,’F’,’R’,’L’ show the image in the anterior, posterior, left, right, head or foot view. The
arrows may be used to incrementally change the degree and direction of rotation of the
rendered image.
Product description
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Figure 7. The 3D window
At the foot of the right hand panel are 8 buttons for quick selection of views for MPR, MIP
and 3D.
The middle panel contains tabs to select the tools and options for 3D management. The
template may be selected by clicking on the image in the template page and it is applied to
the rendered image. There is a wide range of templates but selecting the 3D settings tab
allows the user to create a user defined template either by modifying an existing template or
creating a new one from scratch. Creating a new template should be approached with
caution, as the many settings on the control panel interact and it takes experience, time,
knowledge and a bit of experimenting to achieve the desired effect.
Multi-planar reformat
The standard orthogonal views are shown as default and the right upper pane may be set to
show the resulting image by right clicking in the pane to show the result. The lines may be
rotated in any of the planes to give oblique and double oblique views.
Product description
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Maximum intensity projection (MIP)
MIP may be selected by selecting the MIP option button or right clicking over the top right
panel and selecting the MIP option. The Slab tool panel is displayed and the slab thickness
may be altered by either using the tool panel or by manually adjusting the lines on the image.
Figure 8. MIP reformatting
Batch reformats
Batch planar reformats can be created by selecting the output tab and the 2D batch button.
Batch reformatting may be created from any MPR or MIP view. The reformatting may be
either parallel or radial and the settings may be selected manually or using controls in the
right hand panel that also displays the resulting images. The images may be saved as
DICOM, .jpeg, .bmp images, or .avi movie files, or they may be sent for filming.
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Figure 9. Batch reformat
Curved planar reformat (CPR)
The curved reformat projection allows the user to follow a path along a curved object, usually
a blood vessel. The view is used to straighten out the vessel in order that measurements
may be made of the vessel and any stenosis present. Clicking the CPR button displays the
CPR create screen. The line of the vessel is traced out by inserting points along the path of
the vessel on either the volume rendered image, or one of the orthogonal views, usually the
axial. These points are used to create the centreline and extract the vessel data. On a simple
Product description
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vessel just selecting the start and end point and double-clicking will create the reformat, but
on more curved vessels adding more points will create an improved reformat. Points may be
adjusted to correct the path, for instance if there is a point where two vessels overlap.
Clicking the auto centre line button starts the auto extract process and in most cases the
vessel is traced accurately.
Once the vessel has been extracted, detailed vessel measurements may be made by
selecting the stenosis review and plaque review options from the CPR mini toolbar.
Figure 10. Curved reformatting
Product description
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Dental CPR
Dental CPR is a technique for creating reformats at right angles to the mandible to show
cross-sectional images of the teeth and jaw.
Dental CPR is selected from the options on the preferences button. The study is loaded and
the CPR button selected. The number of CPR lines and interval distance is selected from the
menu bar and using ctrl and left click, points are marked around the mandible. The
reformatting is displayed in less than a second and the resulting reformat images are
displayed in the panel.
Figure 11. Dental CPR Screen
Segmentation
Segmentation is that part of the rendering process in which the volume data set is analysed
and values assigned to points in the data set that define the anatomy. It is this process that
results in the rendered 3D image. The term is also used for the process whereby the
anatomy can be virtually dissected; a typical case would be to remove overlying bone
structure of the skull to view the cranial arteries in a CT angiogram of the head. There are
three main ways to segment an image, outlined below.
Automatic pre-processor segmentation (APS)
The automatic selection tools are applied when the images are loaded. They are related to
the DICOM header and can be configured in the server administration. The tools may also be
selected manually either from the APS button next to the CPR button, or from the mask tab.
Product description
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The algorithms are designed for specific regions. For example, the bone removal tool is good
for isolating the blood vessels from chest, abdomen and pelvis, and for leg run-off, but does
not work so well with head and neck images. If using an APS tool on a study, the designated
algorithm will automatically be applied when the study is loaded subsequently, as there is no
undo function if the results are unsatisfactory.
Freehand
Portions of the image may be removed by simply drawing round the part to be removed. By
selecting Free ROI from the Mask tab and holding down the ctrl key and the left mouse
button the user can draw around the object to be removed with the left and then select the
removal tool from the tab screen, for example Cut.
Automatic
This technique is used to segment out a structure (eg an artery) from the surrounding
anatomy. The function is selected from the Mask panel, Auto is selected and then left click
on the vessel or object in the volume rendered image. After a couple of seconds the selected
vessel is segmented out. The use of the freehand method may be required to tidy the image
and a transparent background may be added by selecting Transparency in the Rendering
options and adjusting the slider.
Figure 12. Segmentation
Initial image
Post automatic bone removal
Product description
Manual selection for segmentation
26
Final image with transparency
Fusion
With AquariusNET it is possible to overlay images from two different modalities on the same
patient, for example a PET scan and a CT scan performed on different machines (as
opposed to a PET/CT Scanner). The studies are loaded from the screen by selecting the
patient name and then right-clicking and selecting the Get list of series with this PatientID
option. A list of the patient’s studies is displayed. After loading, the two studies are displayed
as in figure 13a. The fusion button displays a third set of overlaid images. If the registration of
the images is not correct, automatic registration may be applied from the button on the
Registration tab. If further refinements are required, for example if the two studies have
different magnification factors, there are tools to incrementally change the magnification, the
registration and the rotation of the image. Colour templates may be created and applied,
allowing the user to customise the output.
Product description
Figure 13. Image fusion
13a) Unfused CT & PET studies
13b) After registration
27
Product description
28
Virtual endoscopy
Virtual endoscopy is a technique for volume rendering intra-luminal objects such as the large
bowel or the bronchus. The view shown simulates that of an endoscope.
Endoscopic view is selected from the right-click menu over the rendered image in the top
right window and the 3DV selected. On selecting the colon template, the endoscopy view is
rendered. Figure 15 shows the rendered image of the colon in the upper right window. To
select the area of interest the pyramidal shaped cursor may be moved and rotated on the
orthogonal views and indicates the position and the direction in which the virtual endoscope
is pointing. The user may navigate along the rendered object using the mouse.
Figure 14. Virtual endoscopy view of colon
This tool can be useful for producing one-off endoscopy views of a specific area of interest
but to navigate the entire colon, for example, using this method would be tiresome and time
consuming. Specialised virtual CT virtual endoscopy software is available, designed to
simplify and automate such procedures by automatically defining the path.
Capturing Images and printing
Images may be captured using the right-click menu and selecting the appropriate option. The
results may be viewed by selecting the output tab. The options for printing are
straightforward and the images may be printed to a DICOM printer or a local printer.
Product description
29
Documentation and help
There is no built in help although the manual is clearly written and well designed and is
available as a pdf. There are also quick reference cards to keep by the PC.
Conference
Figure 15. Conference view
The conference facility allows images to be
viewed interactively across a network. The
host (the user initiating the conference)
controls the image, which can be viewed by
other users simultaneously. The remote users
are not able to control the image or use a
cursor to point out anatomy, The remote
user’s window only shows one of the host
window’s images, for example, if a CT scan is
displaying a 2D 4x4 image only the active
window will be displayed on the remote, not
the 4x4. The image is not initially displayed in
the remote(s) until an action has been
performed on the image, i.e. it has been
rotated or the slice changed.
As a tool for communication it seems to work well but the remote image is quite small and
having a tool available for the remote users to point out anatomy would be an advantage to
communication.
Scene
A scene is a file that describes the actions that have been applied to an image dataset. The
scene may be saved and then retrieved later, either for review or to perform further actions
on the dataset.
Methods
30
Introduction
The AquariusNET was tested by installing the server onto the network at the evaluation site
as a local server. Using images and studies from a range of sources, the tools and functions
were assessed and measurements taken.
Hardware test
Server speed
‘PC Mark05’ [2] a software benchmarking program, was used to test the specifications of the
server and the client machines. This performs a series of tests on the components of the PC
under test, then calculates an overall score on the performance. The results are used for
comparison to indicate the relative power of the PC. The greater the number, the more
powerful the PC.
Networking times
Various large volume studies were loaded from the AquariusNET server and the time taken
to display the volume rendered image was recorded.
Power test
The power consumption of the server was measured to using a 2000MU Prodigit power and
energy meter. Comparison of the power consumption with standard PCs was also made.
Images from different modalities were viewed and the imaging tools tested. The tools were
assessed on functionality, ease of use and accuracy.
Technical performance
31
Setting up the server
The AquariusNET VLE server was set up and installed by TeraRecon in the evaluation site
office, taking only a day and requiring only a fixed Internet Protocol (IP) address. For test
purposes, the VLE server was set up as a local server. The Dell PowerEdge 2900 has a
number of cooling fans, which are especially noisy and should be located in an environment
where it would not cause distractions.
Table 7. TeraRecon AquariusNET VLE server configuration
Manufacturer & model
Dell PowerEdge 2900
Operating system
Windows Server 2003 64bit
Processor
2x Intel Xeon 5164 64 bit dual
core processors
Memory
2GB memory
Render card
VolumePro 1000
Hard disk
storage:
C drive:
1 TB RAID 5 image storage
160 GB hard disk
Video card
ATI ES1000 16Mb
Display
15”(38cm) display (1024 x 768)
Networking
2x 1GBit RJ45 network outputs.
Server case dimensions
48cm (H) x 23cm (W) x 70cm (D)
Speed comparisons
To get an indication of the speed of the hardware used by TeraRecon, the PCMark05
benchmark software was used. This gives an overall score, the higher the score the more
powerful the machine. Due to a combination of Windows server and a 64 bit operating
system, the benchmarking system was unable to complete. However, a TeraRecon VSE
machine with similar hardware running 32bit operating system gave a PCMark05 score of
6125.
For comparison the Pentium 4 1.7MHz single core Pentium machine used as the client gave
a score of 1937.
Power consumption
The Dell 2900 server draws significant power and the tests that were run show that even
when switched off, it draws 35 watts (W). When running, the power consumption was 350370W, with the occasional peak to 400W.
The laptop PCs used as client machines drew on average 35-45W, while a tower desktop
machine averaged 130W.
Technical performance
32
The client machine
Setting up
Setting up the client software is straightforward and requires the user only to enter the IP
address of the server into the browser and download the thin client viewing software, which
is a 7Mb download. Once this is installed, an icon is installed on the client machine’s
desktop.
Most of the tests of the client function were assessed using the PC as detailed in table 8.
Table 8. AquariusNET reference client details
Manufacturer & model
Dell Latitude D610
Operating system
Windows 2000, XP, Internet Explorer 6
Processor
Pentium 4 1.6GHz
Memory
1 GB RAM
Video card
ATI MOBILITY RADEON Tru Color Display
Display
SXGA (1280 x 1024)
Networking
Standard network card 100 Mbit.
The client software was also run on machines with a lower specification and it was found that
using older machines for example, on a machine with a Pentium 3 processor, the software
worked for most of the tools, but when rotating rendered images, a number of frames are
missed which can make positioning and rotating the image less precise.
Image transfer times
Table 9. Image transfer times
No of images
Time to load from
AquariusNET server
CT colonography
705 images
3.4s
Leg arteriogram
1496 images
6.5s
Brain CTAngiogram
247 images
1.6s
Procedure
Operational considerations
33
Integrating AquariusNET
To obtain the full benefit from using AquariusNET, integration with the PACS and launching
the 3D tool directly from the patient series on the PACS workstation gives obvious efficiency
gains, so that when viewing a CT or MR study on a PACS workstation for example, selecting
the 3D option automatically loads the dataset into AquariusNET. AquariusNET has various
methods of integrating with PACS systems and TeraRecon has supplied details of some of
the major PACS suppliers that have successfully integrated AquariusNET. Also given are
details of computer aided detection (CAD) software systems that function with AquariusNET.
PACS systems
GE Centricity
AquariusNET can be installed on a Centricity workstation. Contextual
launch is available from GE.
Agfa Impax
Context-sensitive launch is available.
Philips/SECTRA
A plug-in for the Sectra PACS is available that enables the contextual
launch.
Philips iSite
Integration with Philips iSite is available.
Computer aided detection (CAD) software
AquariusNET has been successfully interfaced with Spherefinder from TeraRecon and the
colon and lung CAD software from Medicsight; and there are currently plans to introduce an
interface for iCAD software
Upgrading and options
AquariusNET is continually undergoing revision and during the evaluation of version 1.7
additional tools have become available. Version 1.9 is due for release with tools for
processing dual energy CT and blood-pool contrast processing and plaque analysis.
Alternative approaches
Each of the major PACS providers offers a 3D package for their PACS reporting
workstations, which is either their own 3D package or a third party add-on including, in some
cases, AquariusNET. When considering adding 3D tools to a PACS reporting system,
discussion with the PACS supplier is necessary, as some vendors discourage third party
software being added to the workstations, as it may affect the service agreement levels.
TeraRecon is not the only vendor to offer a server-based thin client solution. Other advanced
visualisation vendors such as Barco and Vital Images are producing thin client versions of
their 3D software. The modality vendors are also widening the scope of the workstations
34
supplied with the CT or MR scanner and employing server based distribution of the 3D tools
on the workstation.
Adding 3D software to existing PC hardware is also an option, especially for use in a non
primary reporting environment, such as a multi-disciplinary team (MDT) meeting. However,
the software requires a high powered machine, having 2 to 4 GB of system memory to
accommodate the large cross-sectional image datasets. This may require the purchase of
suitably equipped PCs and the network speed will have to be adequate to allow for large
studies to load from the PACS in a reasonable time.
When comparing applications other factors to be considered are:
Network speed
The large datasets required for the volume rendering, in some cases 3000 images or more,
can impact on the network traffic, resulting in delay before the entire volume is available. If
the network speed is slow, then using a thin client server model such as the AquariusNET
could be an alternative to upgrading the network.
Licensing model
The AquariusNET licensing model is quite straightforward. The server has one licence and
as many client applications may be used as necessary. The number of users able to access
the system is limited by the amount of memory used on the server and the size of the files in
use.
With other vendor licensing models, software additions to individual PACS reporting
workstations are available with individual licences, where each machine has an individual
licence, or concurrent licences where any number of suitable workstations may have the
software loaded, but only an agreed number may run it simultaneously.
Licensing costs must be taken into account when calculating the overall costs of alternative
approaches.
Upgrades
The software will have upgrade options and it should be clear what upgrades are included in
the servicing agreement. Maintenance upgrades, designed to fix problems or improve
performance, are generally free of additional cost. When a newer version of the software is
released, the upgrade would generally incur an additional cost.
Workflow
In assessing the workflow, consideration must be taken not only of the number of patient
studies, but also the proportion of each type of study. For example, CT vascular and cardiac
studies may require more intensive use of the volume rendering tools than CT head scans.
The 3D tools may already be provided by the modality workstation. The modality may have
advanced tools tailored specifically to the individual modality, for example speciality cardiac
35
tools. These could be used along with a radiology reporting workstation. This would be
dependent on the tools available on each type of workstation and location of reporting
workstations and 3D modality workstations in the department.
By integrating 3D viewing and using a more integrated approach to the PACS for reporting
CT and MRI studies, the improved workflow could reduce reporting times, which may help
departments in meeting the 18 week referral to treatment time target [1].
Service requirements
The AquariusNET server requires:
•
•
•
•
network bandwidth of 100 Mbit/s or better
a fixed IP address for the server
dual power supply 240 V 60 Hz
a separate room or soundproofed cabinet with sufficient air conditioning preferably in
a dedicated server room, if VLE server is to be used.
Economic considerations
36
Pricing & maintenance
The pricing for the AquariusNET is shown in table 10. This comes with a one year warranty,
with full upgrades and servicing.
Table 10. Pricing for the AquariusNET 1.7
Model
Slice capacity
Price
AquariusNET BLUE Server
1700 concurrent CT slices*
£20,000
AquariusNET SE Server
£37,000
AquariusNET VSE Server
£49,000
AquariusNET VME Server
13,600 concurrent CT slices*
£78,000
AquariusNET VLE Server
£110,000
* slice size of 512 x 512 x 12bit
Prices supplied by Linkmed UK and are correct as of May 2008
Extra licences are not required for the client software and the number of users that may
access the system is controlled by the memory on the VolumePro ™ board and the size of
the data sets being used. Service contracts are approximately 10% of the contracted price
and this includes software upgrades, support and servicing.
When comparing AquariusNET with competing products the high capital cost of the server
must be weighed against the cost of additional components that might be required for other
solutions, such as upgrades for the workstations or PC’s, taking into account the number of
licences required.
TeraRecon has recently introduced the iNtuition range which adds a range of tools that
extends the capabilities of the suitable AquariusNET client to the equivalent of a workstation.
See Appendix 2 for more details.
37
Cost comparison of thin client and software only solutions
This is an illustration of the costs involved in providing additional 3D tools to a radiology
reporting PACS workstation. It compares the costs involved in implementing the
AquariusNET thin client system with the costs of a software only solution installed on existing
workstations.
Workload
Figure 16 shows the proportion of the total of imaging and radio-diagnostic procedures
performed in England [3]. The percentages are also typical for an average NHS trust with CT
at 8-12% and MRI 4-6% of the total examinations performed.
Figure 16. Total imaging examinations performed in the NHS in England 2006-7
Fluoroscopy
4%
Radiographs no
fluoroscopy
62%
CT
8%
MRI
4% Obstetric
ultrasound
7%
Non obstetric
ultrasound
13%
Radio-isotopes
2%
Figure 17 shows the numbers of CT and MRIs performed per annum at each NHS trust
arranged in ascending order. This shows that the majority of trusts performed between
10,000 and 30,000 CT scans per annum and between 5,000 and 10,000 MRIs.
Figure 17. Numbers of CT and MR scan per NHS trust.
CT and MRI Scans 2006/7
CT Scan
MRI
38
The number of workstations required depends on the working and reporting practices of each
trust. Trusts with similar workloads may have CTs & MRIs reported only by particular
radiologists or the reporting may be shared by all.
In calculating the numbers of workstation upgrades that might be needed, a number of
issues relating to reporting should be taken into account.
• The number and length of time of each reporting session as well as how the
reporting workload is allocated affects how the workstation is used.
• In a teaching department additional upgrades may be required for training, as the
report on the studies would need to be verified.
• The way workstations are utilised in the department, for example, whether the
workstations are shared or are assigned to specific radiologists may also
influence the numbers or workstations that may need to be upgraded.
Similarly, assessing the size needed for the AquariusNET server would depend on both the
scan study size and an estimation of how many users could be accessing the server
simultaneously. Scan size per study can vary between 20 and 3000+ images and is
dependent upon the scanner specifications and the scanning protocols used.
The prices given for the software only solution are for guidance only and actual figures will
vary. The prices for the AquariusNET product are those quoted by Link Medical.
A number of assumptions have been made in the calculations:
•
•
•
•
•
•
•
•
the packages have comparable functionality
the tools are mainly for use on CT and MRI images
the costs for integration with the PACS/RIS for each of the products are
comparable
the software only product is loaded onto existing PCs or workstations
the fixed costs needed to upgrade the existing PCs are estimates but may be
required to upgrade memory and sometimes the entire hardware. The cost of
upgrading systems may be higher if upgrading equipment from a different PACS
supplier
for up to 9 users, individual licences are purchased. For 10 or more users,
concurrent licensing applies and the price per licence is proportionately reduced.
This will vary from product to product
the client machines for the thin client do not require upgrades
the licensing for the AquariusNET client is limited only by the memory on the
server.
Tables 11 and 12 show calculations for capital and revenue costs for the software only and
AquariusNET models. This is calculated from the capital cost plus 4 years maintenance and
upgrades. The average annual cost is calculated for each combination of workstation
numbers over both 5 and 7 years. For the software only product the costs are also shown
without the hardware upgrade.
As an example, a trust performs 15000 CT and 8000 MRI scan per annum. This works out
at about 88 reports per day for the two modalities. This would require a minimum of 3
workstation upgrades depending on the reporting workflow. This would cost over a 5 year
39
period £11,592 a year or 54p added cost per examination. The calculation for sizing the
AquariusNET is related to the average size of the scans and how many staff will be using the
system simultaneously. An AquariusNET SE server might just suffice (47p), but it would
probably be more realistic to use the AquariusNET VSE model which works out at 62p. If the
number of workstations was increased to four the additional cost per exam would be 72p.
Whilst the above example illustrates the figures involved, the model used is a simple one and
each imaging department would have to decide which would best fit its workflow. However it
can show that using AquariusNET can be a cost effective method of achieving 3D imaging.
Table 11. AquariusNET costs
AquariusNET
BLUE
Server
CT slice capacity
SE Server
VSE Server
VME Server
VLE Server
1700
3400
6800
13,600
27,200
£20,000
£37,000
£49,000
£78,000
£110,000
Maintenance & upgrades
@ 10% per annum
£2,000
£3,700
£4,900
£7,800
£11,000
Total costs over 5 years
£28,000
£51,800
£68,600
£109,200
£154,000
£5,600
£10,360
£13,720
£21,840
£30,800
£32,000
£59,200
£78,400
£124,800
£176,000
£4,571
£8,457
£11,200
£17,829
£25,143
Capital cost
Mean annual cost
Mean annual cost
40
Table 12. Software only costs
Software only
No of workstations
Software licence each ( 10 and
above assumes concurrent licence)
3
5
10
20
30
£11,000
£11,000
£10,000
£9,350
£8,800
£3,000
£5,000
£10,000
£20,000
£30,000
£36,000
£60,000
£110,000
£207,000
£294,000
£5,940
£9,900
£18,000
£33,660
£47,520
£59,760
£99,600
£182,000
£341,640
£484,080
Mean annual cost
£11,952
£19,920
£36,400
£68,328
£96,816
£71,640
£119,400
£218,000
£408,960
£579,120
Mean annual cost
£10,234
£17,057
£31,143
£58,423
£82,731
Capital expenditure
£33,000
£55,000
£100,000
£187,000
£264,000
£56,760
£94,600
£172,000
£321,640
£454,080
Mean annual cost
£11,352
£18,920
£34,400
£64,328
£90,816
£68,640
£114,400
£208,000
£388,960
£549,120
£9,806
£16,343
£29,714
£55,566
£78,446
Hardware upgrades at £1000 per
machine
Total (inc hardware)
Maintenance & upgrades @ 18%
Excluding the hardware costs
Mean annual cost
Purchasing
41
NHS Connecting for Health (CFH) and the National Programme for
IT (NPfIT)
Accountability for the delivery of the NPfIT has been transferred to the Strategic Health
Authorities (SHAs) as part of the NPfIT Local Ownership Programme (NLOP). CFH is
working closely with the 10 SHAs in ensuring activities with LSPs continue effectively. Three
geographic areas have been established, linking the LSPs and SHAs together:
•
North, Midlands and East Programme for IT (NMEPfIT) with six SHAs and Computer
Sciences Corporation (CSC) as the LSP;
•
London Programme for IT (LPfIT) with one SHA and BT as the LSP
•
Southern Programme for IT (SPfIT) with three SHAs. At the time of writing the
appointment of a new LSP has yet to be selected.
Not all commercially available 3D workstation products are necessarily included in each
LSP’s catalogue, as such items may directly affect their service level agreements (SLAs).
Prospective purchasers of 3D workstations and related products might wish to seek guidance
from their local SHA on the available options. It is not compulsory to purchase products in
this way and purchasers are free to source products in whichever way is most convenient
and economic for them.
Determining the clinical requirements
The requirements for additional 3D functionality should be clearly defined prior to investment
in the technology. Examples of these may include:
Adding 3D functionality to existing PACS reporting workstations
This can improve the workflow by reporting, for example, CT and MR scans along with the
other modality studies. It also allows easier access to previous scans and other images
without having to switch between the modality workstation and the PACS reporting
workstation.
Expanding the use of 3D tools outside of the imaging department
The viewing of 3D images, especially volume rendered images, can be used outside the
department where the datasets may need to be manipulated, for example in multi-disciplinary
team (MDT) meetings or for surgical planning.
Providing 3D tools as part of a teleradiology package
Using a server–client based 3D solution can shorten download times when used for
teleradiology, allowing timely viewing of the images.
Sustainable procurement
The hardware used is currently a Dell based server and Dell has its own policy on accepting
products for safe disposal and recycling. Dell offer an asset recovery service for their
products and details may be found on this and on WEEE compliance of its hardware at
www1.euro.dell.com/content/topics/topic.aspx/emea/topics/services/recovery?c=uk&cs=RC1
050265&l=en&s=pad&~ck=anavml
Conclusion
42
AquariusNET is a versatile solution for 3D imaging. The streaming is effective and the results
compare well with those from a modality workstation.
The decision as to whether to use a server-based system over workstation-based systems
will largely depend on the workflow of the department, the case mix of the volume imaging,
the volume tools required and the level of integration required. Pre-processing tools that
automate various tasks may be useful in reducing the time to manipulate the images for
reporting and so help to improve workflow.
If 3D imaging is required principally only to provide MPR & MIP as extra tools to the PACS
workstation, then using a software based solution may be preferred. The costs involved in
using either method would depend on the requirements and workload of the department.
The strength of the server-based system is to provide 3D imaging outside the imaging
department without the need for resource-hungry workstations, allowing radiologists,
radiographers, clinicians and others to view and manipulate the data set in a manner relevant
to their own specialty.
Acknowledgements
43
We should like to thank:
Robert Taylor and David Derby of TeraRecon, for supplying the server, technical assistance
and support.
John Ford and Matthew Westmore of Link Medical for advice and information on
AquariusNET in the UK.
Glossary
44
3D data set The complete set of images that make up the data volume. For example, in CT
this is usually the full series of axial images acquired by the CT scanner.
3D render see volume rendering
Application specific integrated circuit (ASIC) An integrated processor chip that is
designed for a specific application as opposed to a general purpose central processing unit
(CPU). This means there are lower performance overheads over that of a general purpose
CPU.
Batch reformat A series of MPR or MIP images reformatted at set distances.
Central processing unit (CPU) Often referred to as “the processor,” this is where
calculations take place in a computer. On larger systems such as servers, there can be more
than one CPU found on separate circuit boards; on smaller systems such as desktop
machines the CPU is found in a single chip called a microprocessor. The CPU consists of
two components: the arithmetic logic unit (ALU) which performs all logical and arithmetic
operations, and the control unit, which receives instructions from memory, decodes and
executes them.
Client / server model In the client/server model, a server waits for requests from clients, and
after receiving such a request, processes it and sends a response. The communication
between the two peers is based on a protocol, which defines the possible interaction patterns
and the information being exchanged.
Curved planar reformatting The curved reformat projection allows the user to trace a path
along a curved object, usually a blood vessel. The view is used to ‘straighten out’ the vessel
and more accurate measurements may be made of the vessel.
Digital Imaging and Communications in Medicine (DICOM) The ACR-NEMA standard
protocol adopted by manufacturers of equipment associated with medical imaging. The
standard provides a method of linking a series of heterogeneous modalities, workstations
and printers without the need for customised hardware to allow them to communicate and
transfer images
Hounsfield Unit Used in the display of CT images, the Hounsfield Unit is a normalised index
of X-ray attenuation, based on a scale of -1000 (air) to +1000 (bone), with water being 0.
Hot swap disks The hard drive or similar device may be removed or replaced while the
computer system is still in operation. The drive is enclosed in a device that allows easy
removal from the computer system.
Internet Protocol (IP) address An identifier for a computer or device on a TCP/IP network.
Networks using the TCP/IP protocol route messages based on the IP address of the
destination. The format of an IP address is a 32-bit numeric address written as four numbers
separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be
an IP address.
Maximum intensity projection (MIP) Maximum intensity projection is used in medical
imaging to visualize blood flow. MIP finds the brightest voxels in the volume, the voxels lying
Glossary
45
in front of and behind the bright voxel are not displayed. As a result depth information is lost
but density information is preserved.
Multiplanar reformat (MPR) MPR uses the slice images that have been acquired in one
plane (e.g. axial) to reconstruct other slice images in other planes (e.g. sagittal and coronal).
Redundant array of inexpensive disks (RAID) A RAID is a multi disk system where one or
more of the disks provides fault tolerance. A RAID should be able to withstand disk failure
and have the ability to reconstruct the data from a failed disk.
Segmentation Segmentation is the process in the rendering process whereby the volume
data set is analysed and values assigned to points in the data set that defines the anatomy.
It’s this process that results in the rendered 3D image. The term is also used for the process
whereby the anatomy can be virtually dissected, a typical case would be to remove overlying
bone structure of the skull to view the cranial arteries in a CT angiogram of the head.
Server A computer which controls the function of network resources. A server is often
applied to a dedicated task, e.g. a file server controls delivery of files and a network server
controls network traffic. However it is possible for servers to fulfil more than one task if they
have multiprocessing operating systems.
Transmission control protocol/Internet protocol (TCP/IP) TCP is one of the main
protocols in TCP/IP networks. Whereas the IP protocol deals only with packets, TCP enables
two hosts to establish a connection and exchange streams of data. TCP guarantees delivery
of data and also guarantees that packets will be delivered in the same order in which they
were sent.
Thick client In a network system the main application is performed on the data by the client
machine with server in a subsidiary role.
Thin client In a network system the main application is performed on the data by the server
with client machine in a subsidiary role.
Volume rendering The complete data scene is explored and the contribution of each voxel
to the final image is calculated. The rendering algorithm includes factors for voxel value,
tissue type and other properties which determine the colour, opacity and hue of the
projection. These factors vary according to the application and settings of the visualisation
parameters. The additional time and effort in processing the entire data set is balanced by
the increased detail available in the presented image; detail of features below surfaces can
now be viewed in relation to the surface structures.
Virtual endoscopy A rendering technique used to visualise the inner surfaces of structures
where the lumen is of interest such as the large bowel or the bronchus. The view shown
simulates that of an endoscope.
References
46
[1] 18 week referral to treatment time. www.18weeks.nhs.uk/(Last accessed April 2008)
[2] FutureMark.com http://www.futuremark.com/download/
[3] Department of Health hospital activity statistics Imaging and Radiodiagnostics Data
2006/7
www.performance.doh.gov.uk/hospitalactivity/data_requests/imaging_and_radiodiagnostics.
htm
Appendix 1
Supplier contact details
The distributor for TeraRecon in the UK is Link Medical
Link Medical
Unit 9, Moor Place Farm
Plough Lane
Bramshill
Hampshire
RG27 0RF
www.linkmed.org
Manufacturer contact details
TeraRecon
2955 Campus Drive
Suite 325
San Mateo
CA 94403
USA
www.terarecon.com
47
Appendix 2
48
AquariusNET update
AquariusNET has undergone a series of upgrades from version 1.7. Below is a statement
from TeraRecon summarising the changes in the product.
At RSNA 2007, TeraRecon demonstrated two additional optional clients for the AquariusNET
Server. The Aquarius iNtution client is a new, advanced client platform that moves the
applications previously only available on stand-alone workstations into the thin client
paradigm, with the near-term goal of entirely migrating all advanced applications to a thin
client. The AquariusWEB viewer allows a very simple viewer to be launched as a browserbased tool which is fully Javascript-based and requires no administrative privileges for
installation or use. This tool is intended for deployment to referring physicians and for
integration into products such as an EMR or physician portal.
In addition to these innovations, the capability of AquariusNET and its standard Thin Client
software (as described herein) has also been enhanced with various additional refinements
and capabilities.
In terms of server architecture, the most recent version of AquariusNET supports various
features to enhanced enterprise deployment, such as support for Active Directory and LDAP
for account management and headless load balancing and mutual-awareness, for
redundancy, high availability, and better management of multi-site deployments.
Several additional PACS integrations have been completed and are currently available.
TeraRecon has released an optional additional client for the AquariusNET server, called the
Aquarius iNtuition Client. This complements the standard AquariusNET Thin Client and
brings more advanced applications previously only available on the stand-alone Aquarius
Workstation. The Aquarius iNtuition Client can be used as extensively as desired to the
capacity of the AquariusNET Server, once the appropriate server upgrade software has been
purchased.
Table 13. Server prices with iNtuition upgrade
Model
Slice capacity
Price
AquariusNET BLUE Server
£35,000
AquariusNET SE Server
£64,750
AquariusNET VSE Server
£85,750
AquariusNET VME Server
£136,500
AquariusNET VLE Server
£192,500
* slice size of 512 x 512 x 12bit
Author and report information
Evaluation report:
TeraRecon AquariusNET
server for 3D image
reconstruction
Keith Stean, Jonathan Turner,
Dewinder Bhachu, Christopher Dube
PACSnet
Bence - Jones Offices
Perimeter Road
St George’s Hospital
Blackshaw Road
LONDON SW17 0QT
Tel: 020 8725 3315
Email: [email protected]
www.pacsnet.co.uk
About CEP
The Centre for Evidence-based
Purchasing (CEP) is part of the Policy and
Innovation Directorate of the NHS
Purchasing and Supply Agency. We
underpin purchasing decisions by
providing objective evidence to support the
uptake of useful, safe and innovative
products and related procedures in health
and social care.
We are here to help you make informed
purchasing decisions by gathering
evidence globally to support the use of
innovative technologies, assess value and
cost effectiveness of products, and
develop nationally agreed protocols.
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© Crown Copyright 2008
49

CEP 08014 TeraRecon AquariusNET server for 3D image

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