GI Nuclear Medicine: HIDA Scans, Gastric Emptying and More

Nuclear Imaging of the GI Tract:
Gastric Emptying and Hepatic Imaging, and More
Mike Middleton, MD
Professor of Radiology
Texas A&M Health Science Center
OUTLINE
•  Gastroesophageal Reflux Scintigraphy
•  Gastric Emptying Scintigraphy
•  Functional/Morphologic/Metabolic Hepatic
Imaging
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Biliary Scans
Continuing Role of Tc99m-SC ( Liver/Spleen Scans)
Hepatic Blood Pool Scintigraphy (Hemangioma scans)
Role of F18-FDG PET in GI malignancies
•  Gastrointestinal Bleeding
Top 5 Nuclear Medicine Studies at Scott
& White
•  1.PET/CT – 20% for GI Malignancies
•  2. Myocardial Perfusion
•  3. Bone Scans
•  4. *Gastric Emptying
•  5. HIDA scans
•  * fastest growing in 2011-2012
NM Scheduling Program
NM Scheduling Program
Gastroesophageal Scintigraphy
Scintigraphy
milk scans
Milk scans
•  This relatively uncommon study is usually
requested to confirm/quantitate GE reflux in
pediatric or adult patients and helps confirm
possible pulmonary aspiration
•  Tc99m SC is added to formula/Ensure and
imaging for 1 hr in the anterior position, plus
delayed static of thorax at 2-4 hrs
Milk scans: Scheduling
Milk scans: Reflux
Milk scan delayed views:
No confirmedAspiration
Gastric Emptying Scintigraphy
Gastric Emptying Study
?Gastroparesis
Why Order a Gastric Emptying
Study?
•  This type of study can show if solid food is
remaining in the stomach for a prolonged
period
•  In patients with gastroparesis (a disease which
involves paralysis of the stomach muscles and
nerves) food is emptied at a much slower rate
•  More common in diabetics
How does the study work?
•  1 mCi of Tc-99m sulfur
colloid is mixed with eggs
and served to patient
(along with toast and
orange juice)-A standard
meal is important
•  A Tc detector is placed
over the stomach to
monitor the amount of
radioactivity in the
stomach for several hours
after the meal in the ant/
post projection
Gast Emptying scans: Scheduling
Gastric Emptying Patient #2
Gastric
Emptying
Patient #1
Gast. Emptying #2
Patient S Gastric Emptying Study
Ant View
Post View
Standard Worksheet for S&W
Gastric Emptying Graph
Gastric Emptying Scan Results
•  Normal Activity is identified within the
stomach initially
•  Qualitatively reported and quantitatively
reported (using our Scott & White
Database)
•  T1/2 also reported, as determined from the
graph, normal within 2 standard deviations
of curves, and a T1/2 of 90-120 minutes
Gastric Emptying: Concensus
Statement - 2008
•  Tougas method variation- supports retention
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rates as a more standard method
Recommends imaging 0, 1, 2, and 4 hrs
Qualitatively reported – rapid/normal/
delayed
The 4 hr time interval found to be more
sensitive for detection of gastric emptying
Ant/post with geometric mean, etc
Gastric Emptying: Concensus
Statement - 2008
•  Rapid emptying defined as <30% retention
at 1 hr is indicative of rapid GE
•  (Normal 30-90% retention at 1 hr)
•  Delayed- defined as:
•  >90% retention at 1 hr,
•  >60% at 2hr,
•  and > 10% at 4hr
Gastric Emptying: Concensus
Statement - 2008
•  If Delayed•  Quantitatively reported based on 4 hr
•  11-20% retention at - Grade 1 (mild)
•  21-35% retention – Grade 2 (moderate)
•  36-50% retention – Grade 3 (severe)
•  >50% retention – Grade 4 (very severe)
Treatment of Delayed Gastric
Emptying
•  Treatment of gastroparesis is based on controlling symptoms
(particularly nausea and vomiting) and improving delayed gastric
emptying.
•  Mild gastroparesis with easily controlled symptoms is generally
controlled with dietary modifications ( liquid supplements, etc)
•  But moderate or severe gastroparesis requires prokinetic (ie
metaclopramide=Reglan, domperidone, eythromycin) and antiemetic
medications ( ie promethazine=phenergan)
•  Uncommonly, surgical intervention is considered.
Hepatobiliary Scintigraphy
Common Hepatic
Studies on a typical
day utilizing the Scott
& White NM
Scheduling Program
Scheduling a HIDA
scan with CCK
General
•  Biliary iv agents are rapidly excreted by
hepatocytes and delivered to bile
unconjugated
•  The liver, biliary system, bowel, and
sometimes portions of the stomach are
normally visualized
Objectives
•  Detect cystic duct obstruction (ie. As in
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acute cholecystitis)
Detect CBD obstruction
Detect biliary leaks
Detect GB dysfunction
Detect or assess post-op GI tract
complications
Assess neonatal jaundice
Technique/Preparation
•  Pharmaceuticals
•  5mCi Tc-99m Disofenin
•  5mCi Tc-99m Mebrofenin
•  Patient Preparation
•  Fasting >4hrs but <24hrs
•  If >24hrs, administer CCK to contract GB
(0.02ug/kg Sincalide, slowly iv)
Technique
•  LFOV Camera, ant views
•  Dynamic 1 minute (summed 5 min images)
•  Extra views may help distinguish GB from
bowel prn, ie LAO, Rt lat.
•  Shielding with lead may be helpful if trying
to bring out a faintly visualized GB or gut
•  Exam tailored to question being asked
Technique
•  After imaging 1 hr, images checked
•  Interventions made until examination
considered complete
•  Sometimes delayed or ultra-delayed views
are required
Technique
•  Interventions
•  Water po to wash out duodenal activity to distinguish it
from GB
•  MSO4 to increase sphincter of Oddi to accelerate GB
visualization (.02ug/kg slow iv)
•  Milk, fatty snack, or CCK (sincalide) to increase
contraction of GB and increase bowel visualization
•  Repeat c/ Phenobarbitol to induce liver enzyme activity
for several days in a neonate if nonvisualization of
Bowel by 24 hrs
SAMPLE FLOW
SCHEME:
HIDA Scans
Interpretation
•  Nonvisualization of GB at 4hrs
•  Activity normally enters the GB passively from
the ductal system. In acute cholecystitis, there
is usually cystic duct obstruction preventing
bile from entering the GB (90-95% of pts)
•  DDX: acute cholecystitis, s/p cholecystectomy,
prolonged fast or recent fatty meal, chronic
chlocecystitis (rare)
Interpretation
•  Rim or Stripe Sign
•  Nonvisualization of the GB with increased
activity at the liver margin near the GB fossa
•  Seen in pts with sever acute cholecystittus and
has a 20-40% incidence of grangrenous
cholecystitus
Interpretation
•  Delayed visualization of the GB
•  After 1 hr by convention , sometimes
considered if >30 minutes after bowel has been
confirmed, (even if within the 1 hr)
•  Most commonly seen with chronic cholecystitis
Interpretation
•  Delayed visualization of Gut with GB
visualization
•  NONspecific
•  DDX: chronic cholecystitis, post-opiate
administration, partial CBD obstruction, other
inflammatory bowel processes (including
pancreatitus, etc)
Interpretation
•  Leak
•  Most often seen post-op (ie lap
cholecystectomy) or penetrating trauma
•  Usually seen as intense activity nor conforming
to normal anatomical structures…..multiple
views help (ie right pericolic gutter activity)
Interpretation
•  Hepatic uptake only (nonvisualization of
the ducts, GB, and gut)
•  Acute CBD obstruction vs cholestatic
hepatitis….however the clinical presentations
of these generally differ
•  Hepatic uptake may be a clue to interpretation,
being more diminished in hepatitis.
•  NOTE: In complete CBD obstruction – it is rare
to see GB activity because of backpressure in
the biliary system
Interpretation
•  Bowel distortions
•  Pacreatitus or masses may compress the
duodenum and cause non-vis. of the 3rd portion
•  Prior bowel surgery
•  Cut-off CBD sign
•  Stone impacted in the CBD
Interpretation
•  Parenchymal defects
•  Any lesion which displaces hepatocytes may
cause a liver defect on early images (ie mets,
abscess, cyst, tumor)
•  Hepatomas and adenomas occasionally show
delayed uptake of HIDA compared with
surrounding liver
Interpretation
•  SPECIAL PROCEDURES
•  GB Ejection Fraction (GBEF) Commonly
Performed
•  When chronic acalculous cholecystitis is suspected
for chronic RUQ pain (not an indication for an
emergency study)
•  GBEF of >35% considered normal at 20
minutes post CCK (sincalide) administration
•  <35% GBEF can be seen with Chronic
Acalculous Cholecystitis
Treatment of Biliary Conditions/
Cholecystitis:
*Generally is surgical for acute
cholecystitis or elective surgery for a
biliary dyskinetic syndrome/chronic
acalculous cholecystitis. Biliary leaks
and obstruction also require surgical
evaluation.
Role of Tc99m Liver/Spleen
Scans
Hepatic Scintigraphic Imaging
with Tc99m- SC
•  Technique/Dose
•  2-10mCi Tc99m SC, iv
•  Simple, immediate planar imaging, with SPECT
depending on indication
Hepatic Scintigraphic Imaging
with Tc99m- SC
•  AnatomicEvaluation
•  SPECT almost always helpful
•  Intrahepatic Focal Defects
•  Functional Evaluation
•  Cirrhosis,etc
•  Use with other radiotracers
TABLE 2:
Intrahepatic Focal Defects
with Tc99m Sulfur Colloid
Function with Tc99m SC
•  More utility in an era of U/S, CT, MR, and
other anatomic imaging methods
•  On a normal LS scan, vast majority of
phagocytic function is by Liver > spleen
>>bone marrow
•  Colloid shift is determined when more spleen
and bone marrow take over this function.
•  Degree of shift proportional to severity of
hepatic dysfunction
Colloid shift signifies parenchymal liver disease
Moderate to marked Colloid Shift:
Advanced parenchymal liver disease with
ascites (photopenia around liver)
Severe Advanced Cirrhosis:
LS Scan (Anterior and Posterior View)
Hypertrophied
Caudate lobe:
Budd-Chiari
Syndrome
(portal htn with a
degree of hepatic
failure)
Blood Pool Hepatic
Scintigraphy
Hemangioma Scans
Scheduling a Hemangioma scan
requires
Tagging, initial imaging, then delayed
blood pool imaging
Hepatic Hemangiomas:
Epidemiology
•  A. Common lesion of the liver with an autopsy
determined incidence of 5-8% of the population
•  B. 2nd most common hepatic tumor exceeded
only by metastases
Hepatic Hemangiomas:
Pathology
•  Lesions may be single or multiple. They are
composed of tangles of thin-walled, cavernous
blood vessels and spaces separated by scanty
connective tissue stroma.
Hepatic Hemangiomas:
Imaging
•  Masses in the liver are often discovered serendipitously
by CT or U/S.
•  A. CT and U/S
•  Because the specific CT and/or U/S criteria for
hemangioma cannot always be reliably
demonstrated, further imaging often may be
necessary to distinguish hemangiomas from other
liver lesions.
Hepatic Hemangiomas:
Imaging(cont.)
•  B. MRI – hemangiomas characteristically appear as a
low signal or isointense mass on T1 weighted images
and homogenously bright on T2 images.
•  1. High diagnostic accuracy
•  2. May not distinguish hemangioma from a vascular
met
•  3. Use in special cases:
•  a. Less than 2cm
•  b. lesions adjacent to normal vascular structures
•  c. clarify atypical or indeterminate Tc-99m RBC
scintigraphic studies
4. Costly
Hepatic Hemangiomas:
Imaging(cont.)
•  C. Tc-99m RBC scintigraphy – The classic finding of
increased activity on the 2-3 hr blood pool images with
absent or reduced early arterial blood flow (on
dynamic images)
•  1. High diagnostic accuracy
•  2. Generally can distinguish hemangioma from a
vascular met
•  3. Potential resolution problems
•  Less than 2cm, although improved with SPECT/CT
•  Lesions adjacent to normal vasculr structurs, SPECT/CT
may help
•  4. Less expensive than MRI
Tc99mSC and Delayed Tc99m Blood Pool Images
Comfirm a large Right Hepatic Hemangioma
Hemangioma in a 66yo man: U/S shows well circumscribed 3cm
Mass in the right lobe of the liver. Coronal and axial delayed blood
pool SPECT confirm blood pooling in the mass c/w a Hemangioma.
Role of F18-FDG PET in Colorectal
Ca and Hepatic Mass Imaging
NM Scheduling Program
P.ositron
E.mission
T.omography
WHY P.E.T.?
“Disease Is a Biological Process
and PET Is a Biological Imaging
Technique That Uses Molecular
Probes”
Michael Phelps MD, Ph.D.
Why PET?
Isotopes of naturally occurring
elements
High sensitivity
Uniform high resolution
Superior attenuation correction
Superior quantification
High clinical sensitivity & specificity
Why utilize PET ?
•  PET displays a 3D whole body view with a single
scan enabling clinician to see distant metastasis
•  PET can differentiate malignant from benign tumors
•  PET stages and monitors the treatment response to
therapy more accurately than conventional methods
•  PET alters course of treatment in over 40% of cases
providing better patient outcomes
Where is PET Utilized?
•  Oncology: All types of Cancer Diseases
•  Neurology: Dementia, Epilepsy, Alzheimer s
•  Cardiology: Myocardial perfusion and viability
Anatomic vs Functional
Imaging
•  Even when structural changes occur
they can be hard to detect
•  Example: lymph node metastases
typically need to grow larger than 1 cm to
be called positive on CT
•  Most diseases are functional in nature
and structural changes are secondary
F18 Fluorodeoxyglucose
•  18[F]-2-deoxyglucose
•  109.8 minute t ½
•  Positron annhilation yields 2 511
kev gamma rays in coincidence
(approximately 180 degrees apart
and within 10 –9 seconds)
•  18[F] - cyclotron produced
Normal distribution pattern of FDG
Note:
evidence of excretion via urinary and
gastrointestinal system, faint hepatic uptake,
some soft tissue and bone uptake, and definite
cardiac activity.
Clinical PET Procedure Mix
Oncology
85%
Cardiology
5%
Neurology
10%
Why FDG for Tumors?
Answer:
hypermetabolism
F-18 FDG PET
•  Approved for initial staging, restaging, and
evaluating further treatment response of several
GI malignancies
•  Colorectal
•  Esophageal
•  Gastric
•  Pancreatic
•  Hepatic Primary Malignancies
72 year old male s/p R
hemicolectomy for colon Recurrent Colon Carcinoma
CA. CEA increased to
12.5 in 5/99.
CXR showed stable RUL
nodule and CT of abdm
showed stable aortocaval
and Left common iliac
adenopathy. PET
ordered to r/o recurrence.
PET showed extensive
mets to retroperitoneal
lymph nodes. The R
upper lung nodule not
visualized and is most
likely benign in origin.
F-18 FDG restaging
Colorectal Ca
•  Has replaced Tc-99m CEA scan and In111Oncoscint because of increased accuracy in
restaging pts with colorectal ca
•  Aids in the detection of hepatic metastases
Case Example
•  73 yo male underwent right hemicolectomy
for cecal mass
•  Mass described as poorly differentiated
adenocarcinoma
•  0 of 7 pericolonic nodes were positive
•  Reported as a stage I, T2N0M0, grade 3 lesion
•  5 year survival rate of 90%
Follow-Up
•  Patient was scheduled with a follow-up
regimen with the oncology service
•  CEA q 2 months x 6, followed by q 4 months x
6
•  Patient to be followed by general surgery
•  Follow-up colonoscopy within 6 months to 1
year
Results of Follow-Up
•  CEA results
•  Pre-op: 3.8
•  7 weeks post-op: 5.4
•  12 weeks post-op: 14.9
PET Scan
•  Due to a steadily rising CEA, patient was
scheduled for a PET scan to assess tumor
recurrence
•  Patient underwent PET scan 5 months postop
PET Results
•  PET scan was reported as abnormal
•  Finding #1: large hypermetabolic lesion within the
posterior segment of the right hepatic lobe, containing a
central, necrotic region
•  Most likely a metastatic lesion
•  Finding #2: Hypermetabolic activity in the region of
prior anastamosis, near the hepatic flexure
•  Activity is greater than expected for normal post-operative
changes
•  Most likely a focal recurrence of the colonic neoplasm
PET in Evaluation of Rx
response
•  F18 FDG Pet helpful in monitoring
treatment response
•  Systemic chemotherapy
•  Surgical resection of hepatic lesions
•  Local chemo-embolization of hepatic lesions
PET
PET
Gastrointestinal Bleeding
•  GI Bleeding Objectives•  To localize the approximate site of GI bleeding
prior to angiographic or surgical procedures.
•  More appropriately done for Lower GI bleeding
and usually done if upper and lower endoscopy
are negative
Gastrointestinal Bleeding
•  Rationale:
•  Blood pool labeling is performed, and serial
images of the abdomen can detect blood that
leaves the blood pool into the bowel, with a
bleeding rate as slow as 0.1 ml/min. (10x
slower than angiographic)
Gastrointestinal Bleeding
•  Rationale (continued):
•  Detection of GI bleeding is dependent on 4
basic factors:
•  The rate of hemorrhage
•  The nature of the bleeding, ie continuous or
intermittent
•  The site of hemorrhage
•  The specific characteristics of the agent utilized
–  Tc99m Tagged RBCs more common
Gastrointestinal Bleeding
•  Summary:
•  Sensitivity 91%, Specificity 95%
•  Because angiography has a lower sensitivity
and is more invasive, a GI bleeding scan is a
helpful & reasonable preliminary imaging study
if available
•  Many bleeding sites spontaneously resolve, but
surgical intervention always should be
considered.
SUMMARY
•  Standardized methodology for gastric emptying is
suggested retention rates are now considered standard
•  There are many choices for scintigraphic functional and
anatomic imaging of the liver.
•  A familiarity with a variety of common nuclear scans to image
physiologic, metabolic, or morphologic aspects of the liver is
helpful
•  PET/CT will continue to grow as a metabolic modality for
GI and hepatic malignancies
•  Gastrointestinal bleeding exams can be helpful in
localizing lower GI bleeding prior to angiography
REFERENCES
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Abell, Thomas, et al, Consensus Recommendations for Gastric Emptying Scintigraphy:
A Joint Report of the American Neurogastroenterology and Motility Society and the
SNM, AJG 2008; 103: 753-763.
Middleton, ML Scintigraphic Evaluation of Hepatic Mass Lesions: Emphasis on
Hemangioma Detection Seminars in Nuclear Medicine, Vol 26, No 1, Jan 1996, pp
4-15.
Middleton, ML, et al Hepatic Mass Lesions: Scintigraphic Update with Emphasis on
Hemangioma Detection Nuclear Medicine Annual 1994, Raven Press , pp55-90.
Middleton, et al The importance of early dynamic imagesin diagnosing hepatic
hemangiomas . Clin Nuc Med 18:262, 1993.
Fink-Bennett, D, Augmented Cholescintigraphy: Its Role in Detecting acute and chronic
disorders of the Biliary Tree: Seminars in Nuclear Medicine, Vol 21, No 2, 1991, pp
128-139.
Fogelman and Maisey s An Atlas of Clinical Nuclear Medicine (and Slide Series):
Mosby Pub, 1988.pp481-595.
Clinical PET, Ed. Von Shulthess, GK, Lippincott Williams & Wilkins, Chptrs. 1, 17,
pp195-207.
Michael L. Middleton, MD, and Mark D. Strober, MD, Planar Scintigraphic Imaging of
the Gastrointestinal Tract in Clinical Practice,Semin Nucl Med 42:33-40 © 2012
Elsevier Inc
Thank You………..
Scott & White Memorial Hospital and Clinic
Texas A&M University Health Science Center