TİROİD NODÜLLERİNDE RADYOFREKANS ABLASYON TEDAVİSİ

US GUIDED RF ABLATION
OF THYROID NODULES
Prof. Dr. Cem Yücel
GAZI UNIVERSITY SCHOOL OF MEDICINE
DEPARTMENT OF RADIOLOGY
THYROID NODULES
• Nodule incidence:
– Palpation: 4-8 %
– Ultrasound: 10-41 %
– Autopsy: 50 %
• Malignity rate: ≈ 10 %
• Indications for therapy in benign nodules:
– Compression symptomes
• Pain, disphagia, coughing, feeling of foreign material)
– Cosmetic
– Autonomously functioning nodules
STANDARD TREATMENT
• Malignant:
– Surgery
– Recurrent tumors:
Surgery is challenging, comp. rate ↑
• Benign:
– Levothyroxine supression?
– Surgery
INDICATIONS FOR RF ABLATION
• Benign symptomatic cold nodules
• Autonomously functioning nodules
• Well-differentiated malignant tumor recurrences
PRE-PROCEDURAL EVALUATIONS
• US evaluation:
– Properties of the nodule(localization, neighboring
structures, size, echogenicity, presence of
calcification, ratio of solid component, internal
vascularity)
– Nodules with malignant characteristics are excluded
– Determination of nodule volume
• Biopsy:
– Malignity should be excluded by at least two
seperate FNAB’s or one core biopsy
PRE-PROCEDURAL EVALUATIONS
• Laboratory tests
– Complete blood count
– Coagulation parameters
– Levels of thyroid hormones, auto-antibodies,
calcitonin, T3, T4, TSH,
PRE-PROCEDURAL EVALUATIONS
• Informed consent
– Size of ablated nodules decrease in months.
– More than one sessions may be necessary.
– Treated nodule or other nodules may regrow and
additional treatment may be required.
– Patient may feel various degrees of pain during the
procedure.
– Complications.
RF GENERATOR
• Generator: RF power between 0-200 W
– During thyroid ablation 20-50 W (max 100 W)
– Impedence
RF ELECTRODE
• Electrode:
– Straight, internally cooled
– 19 gauge, length 7 cm, active tip: 0.5, 0.7, 1.0, 1.5 cm
PROCEDURE
• Patient in supine position, mild neck extension
• Local anesthesia
• Approach:
– Trans-isthmic
Entire length of the electrode can be visualized
Minimal exposure of heat to danger triangle
Electode passes sufficient amount of thyroid
parenchyma(to avoid any change of needle position and
leakage of hot ablated fluid outside the thyroid)
– Craniocaudal
– Lateral
PROCEDURE
• “Moving-shot” technique (Baek et al.)
– As thyroid nodules are ellipsoid in shape, prolonged
fixation of the electrode is dangerous to surrounding
critical structures
– Initially, the electrode is positioned at the peripheral
deepest portion of the nodule
– When an echogenic area appears at the targeted area
and impedence increases, RF power ic decreased and
the electrode tip is moved back to an untreated area.
– In cystic nodules, all fluid is aspirated before ablation.
– When all nodule is ablated and transient hiperechoic
areas are observed all through the nodule, procedure
is terminated.
FOLLOW-UP
• US follow-up:
– At 1, 3, 6 and 12. months
– Volume decrease:
1. month 33-58 %, 6. month 85 %
– Echogenicity: ↓ than before ablation
– İntranodular vascularity (-)
• TSH, T3, T4
• Resolving of complaints
RESULTS
Baek JH et al. Korean J Radiol. 2011 Sep-Oct;12(5):525-40
COMPLICATIONS
Baek JH et al, Radiology. 2012 Jan;262(1):335-42
OUR EXPERIENCE
•
•
•
•
13 cases, 20 nodules(11F, 2 M)(Age range=33-72, med. 48)
10 euthyroid, 4 with hyperthyroidism
Nodule volume = 0.6-50 cc, medium 8 cc
Follow-up:
–
–
–
–
–
1. month(11 cases, 18 nodules): 10-83 %↓(med. 48 %)
3. month(5 case, 7 nodule): 34-90 %↓(med. 61 %)
6. month(1 case): 89 %↓
In all cases hormone levels returned to normal
In 1 case transient hoarseness
50 y, F, Euthyroid
Pre-ablation: Volume=16 cc
Post-RF 1. month: Volume=4.5 cc (72 %)
Post-RF 6. month: Volume=1.7 cc (89 %)
42 y, M, Hyperactive
Pre-ablation: Volume=6 cc
POST-RF
3. MONTH
Volume = 1.5 cc ( 75 % )
38 y, F, Euthyroid
Pre-ablation: Volume=3.3 cc
Per-RF
Post-RF
1. MONTH
1.4 cc ( 58 % )
3. MONTH
0.7 cc ( 79 % )
In the management of benign thyroid
nodules, RF ablation is an effective and
safe alternative to surgery in experienced
hands