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Imaging of Thyroid Lesions.pptx
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- 2. IMAGING • Plain Radiography •USG • CT/MRI • Nuclear scintigraphy
- 3. Plain radiograph • Paratrachealsoft tissuemass • Tracheal shift/narrowing • Calcification • Retrosternal extension • Bony destruction • Pulmonary metastasis
- 4. Roleof USGin thyroiddiseases • Solid vscystic lesions. • Benign vsmalignant lesions • Nodule detection when physical examination isunequivocal. • Thyroid nodules from other cervicalmasses
- 5. Differentiating features Benign Malignant Internal consistenc y Cystic componen t Predominantlysolid composition Echogenicity Hypoechoic /iso /hyper More marked Hypoechogenicity Margins Well marginated Spiculated, illdefined, irregular
- 6. Benign Malignant Sonoluscent peripheral halo Absent Peripheralvascularity Intranodal vascularity
- 7. Benign Malignant Wider thantaller Taller than wider Peripheralcalcification Scattered echogenic Micro calcification Histopathology -colloid goiter
- 8. Thyroid image reportingand data system(TIRADS) • TIRADS 1:normal thyroid gland – 0% • TIRADS 2: benign lesions – 0% avascular anechoic lesion with echogenic specks vascular heteroechoic, non-encapsulated nodules with peripheralhalo
- 9. TIRADS 3: probablybenign lesions <5% hyper, iso or hypoechoicnodules partially formed capsule peripheral vascularity..
- 10. Suspicious lesions • TIRADS4: solid component high stiffness of nodule on elastographyif available markedly hypoechoic nodule microcalcifications taller-than-wider shape microlobulations or irregularmargins • subclassified as4a, 4b, and later 4c
- 11. TIRADS 4a: onesuspiciousfeature (5-10%) TIRADS 4b: two suspicious features(10-80 %) TIRADS 4c:Three/foursuspicious features(10-80%) TIRADS 5: probably malignant lesions (more than 80%riskof malignancy) TIRADS 6: biopsy proven malignancy
- 12. high suspicion uspatternrepeat usin 6-12 months low or intermediate suspicionus pattern repeat usat 12-24 months >1cm nodules with verylow suspicion pattern repeat usat >24 months <1cm nodules with verylow suspicion uspattern no need of followup
- 13. Cystic thyroid lesions •Colloid cyst • Sharply defined walls • Large comet tail artifact • Cystic Variant of papillary carcinoma • Irregular walls • Lobulated margins • Presence of blood vessels in solid component
- 14. ThyroidNodules • Discrete lesion/swithin the substance of thyroid gland • sonographically distinct from surroundingparenchyma • 85%benign • Benign • Colloid nodule • Follicular adenoma • Thyroid cyst • Malignant • Follicular • Anaplastic • Medullary carcinoma • Lymphoma
- 15. • Colloid nodule •isoechoic to hypoechoic with degenerative changes • Follicular adenoma • Hyper, hypo, isoechoic • Hyper vascular on colour flow • Degenerative changes • FNAC can’t differentiate it from follicular carcinoma
- 16. Papillary carcinoma USG • Hypoechogenicity •Microcalcification -Finepunctate • Primary lesion and lymph nodes • Hypervascularity • Lymph node – cystic, thick nodular walls, calcification • Lateral aberrant thyroid • CECT: Heterogeneousenhancement
- 17. Follicular carcinoma USG • Hypoechoicill defined lesion withThick irregular capsule • Types: Minimally invasiveEncapsulated Invasive Not well encapsulated with vascularinvasion Central chaotic vascularity
- 18. Medullary carcinoma Ultrasound • Hypoechoicsolid nodules with coarse internal calcifications. • Involved lymph nodestypicallycalcify. CT • Both primary and metastatic lesions usually haveirregular densecalcific foci within. • In the chest, bullae formation and pulmonaryfibrosis – desmoplastic reaction Nuclearimaging • do not concentrate radioactiveiodine – doesn’t arise from thyroid follicular cells FDG-PET • ~75%(range60-95%)sensitive for metastatic disease6
- 19. Anaplastic carcinoma • Fatal-elderly women,long standing goitre USG • Ill defined, heterogenous • Hypoechoic lesion encasing the vessels CT Extent/ calcification / necrosis
- 20. Primary Lymphoma •Old agedfemales Hashimotos Nodular/ diffuse Nuclear: I-131 Coldnodule
- 21. Crosssectional imaging CT/MRI •Better delineation of lesion withinthyroid. • Extension into adjacent neck and mediastinaltissues. • Detection lymph nodalmetastasis • Follow up for recurrence
- 22. Nuclear Scintigraphy • Functionalinformation about thethyroid • Radiotracer :- Oral I-123,I-131 I.v Tc-99mpertechnate Normal uptake 10-30%
- 23. Nuclear scintigraphy indications •Assessment of anatomy • Assessment of function • Postoperative assessment • Detection of nodule– hot or cold orwarm • Detection offunctional metastatic tissue in known caseof thyroid ca. • Detection of retrosternalgoitre.
- 24. DIFFERENTIALDIAGNOSIS COLD NODULE (8-25% chancesofmalignancy) • Thyroiditis • Cyst • Fibrosis • Non functioning adenoma • Multinodular goitre • Malignancy HOT NODULE (Malignancy rare) • Functioning adenoma • Thyroiditis
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- 26. CONTRAST ENHANCEDULTRASOUND • Enhancementpattern isrecognised. • Ringenhancement correlates with benign lesions while heterogenousenhancement correlates with malignantlesions. • Showsenhancement of septa in malignant nodules in arterialphase • Benign septae do not show enhancement. COLLOID
- 27. ELASTOGRAPHY • Obtains informationabout tissue stiffnessnon invasively. • Elastography score (ES)is assigned basedon colour pattern of lesion relative to sorrounding tissue. • Red ( soft tissue), green ( intermediatedegree of stiffness), blue ( anelastictissue). • An ESof 4-5 is highly predictive ofmalignancy (sensitivity 94%).
- 28. ELASTOGRAMPATTERNS • P A T T E R N1: Wholenodule elastic • P A T T E R N2: Most part elastic, inconsistent inelastic areas • P A T T E R N3: Constantportions of anelasticareas • P A T T E R N4: Uniformlyanelastic
- 29. PETscan • Useful adjunctto scintigraphy when evaluating tumorsthat don’t concentrate radioactiveiodine • Follow up of thyroidcarcinoma • Metastatic thyroid carcinoma
- 30. PERFUSION CT • Measurestemporal changesin tissue density after iv contrast. • Quantifies abnormal vasculature within tumours, thus allowing assessment of tumouragressiveness. • Benign tumours havebeen found to show lowBF and MTTcompared to malignanttissue.
- 31. DIFFUSION WEIGHTEDMRI: • Performedwith the aim ofdifferentiating malignant from benignlesions. • This technique evaluates rate of microscopic water diffusion in tissues. • All benign nodules havehigher meanADCvalue than malignant nodules.
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- 39. Parathyroid adenoma • Caudalto the inferior pole of thyroid lobe • Echogenic curvilinear capsule seen anteriorly • Arc of prominent vessels surrounding and leading into the nodule
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