Presentation on theme: "Emerita a. Barrenechea MD, FPCP, FPSNM Department of Nuclear Medicine St. Luke’s Medical Center Veterans Memorial Medical Center Asia Oceania Thyroid Association."— Presentation transcript:
Emerita a. Barrenechea MD, FPCP, FPSNM Department of Nuclear Medicine St. Luke’s Medical Center Veterans Memorial Medical Center Asia Oceania Thyroid Association Congress Bali, Indonesia October 22, 2012
What is available? Planar/SPECT/SPECT-CT imaging (e.g. 99m Tc- based radiotracers, 123 I, 131 I) Positron emission tomography ( PET) Ultrasonography (USG), USG elastography Computed tomography (CT) Magnetic resonance imaging (MRI) Optical coherence tomography
Ultrasonography Most common Facilitate diagnosis of clinically apparent nodules Most affordable Primary imaging modality American Thyroid Association other authoritative bodies
Ultrasonography Patterns most frequently associated with thyroid CA Microcalcifications Relative hypoechogenicity of the nodule Irregular margins or absent halo sign Solid pattern and taller-than-wide morphology Intranodular vascularization Should not be used singly
Suggestive of a follicular lesion
Thyroid Nodule Evaluation Fine needle aspiration cytology is cornerstone Simple Useful Cost-effective BUT evaluation of non-diagnostic and insufficient FNA samples continues to be a problem
Elastography Sonographic estimation of rigidity/deformability of tissue change in Doppler signal after external application of pressure/vibrations by tracking shear wave propagation May correlate with: palpable consistency of goiter cytology of a nodule May enhance cancer-prediction in non-cystic, non-calcified thyroid nodules or inflammatory conditions
Computed Tomography 3D image of internal organs Uses 2D X-ray images “Windowing” allows better visualization of targeted organs Cannot detect small nodules Uses: Detection of goiter or larger thyroid nodules Evaluation of cervical lymphadenopathy Local tumor extension Mediastinal/Retrotracheal extension
Substernal Thyroid (CT)
Magnetic Resonance Imaging Anatomic imaging only Evaluation of thyroid size and shape Preferable than CT No patient exposure to radiation No need for contrast study
Magnetic Resonance Imaging Arterial spin labeling (ASL) Differentiation of autoimmune thyroid conditions Treatment response evaluation in Graves disease Diffusion weighted imaging (DWI) Apparent diffusion coefficient (ADC) can be used to differentiate benign from malignant nodules (Schueller) Benign = low signal intensities on DWI + high ADC Malignant = high signal intensities on DWI + low ADC
MRI of thyroid gland
Optical Coherence Tomography (OCT) high-resolution, real-time, cross-sectional imaging of tissues Optical Coherence Microscopy (OCM) high magnification cellular imaging 1–15 µ resolution High-resolution images comparable with histopathologic images Both use infrared light New Modalities
Subacute Thyroiditis 30/M Hyperthyroid symptoms 131I thyroid scan Thyroid not visualized Only background radioactivity
Whole Body 131 I Scintigraphy
Remnant Thyroid Complete Ablation Complete ablation of Residual thyroid Tissue in neck Very low/ Undetectable Level of Tg
Functioning Mets In Both Lungs Initial Presentation Post-SURGERY Post remnant Ablation I II III Proceed to to stage IV I-131 Therapy of Functioning Metastases IV
SPECT/CT Improved detection and localization of disease (superior to SPECT alone) In radionuclide therapy, provides more insight into the effectiveness of targeting and may explain the observed response
131 I SPECT/CT 131 I SPECT-CT is more accurate than 18 FDG PET-CT in well-differentiated thyroid cancer regional and distant metastasis residual/recurrent disease The most important advantage of fusion 18 FDG PET-CT and 131 I SPECT-CT is detection of metastasis in normal sized lymph nodes.
131 I SPECT/CT
TCA with mets
99m Tc sestamibi-Parathyroid
Medullary Thyroid Carcinoma
Whole body 131 I Scintigraphy 78/M, (+) 13-year FU, (+) rising Tg up to 1447 µg/L
PET in TCA with increasing TG, negative TBS
18 FDG PET/CT Well-established usefulness in WDTC if Tg (+) and WBS (–) Helpful in anaplastic/medullary thyroid cancer May be complimented by PET studies using 68 Ga-DOTATOC and 18 F-DOPA when looking for recurrent disease
Indications of PET/CT residual or recurrent thyroid cancer WHEN elevated Tg + RAI scan (–) When localized, may require surgery or radiotherapy Extent of poorly differentiated TCAs & invasive Hurthle cell Cas Treatment response following systemic or local therapy
BNMS Guidelines on TCA Assessment of patients with elevated thyroglobulin levels and negative iodine scintigraphy with suspected recurrent disease. To evaluate disease in treated medullary thyroid carcinoma associated with elevated calcitonin levels with equivocal or normal cross-sectional imaging, bone and octreotide scintigraphy - for alternative PET imaging with 68Ga- DOTA- octreotate (DOTATATE), DOTA-1-NaI3- octreotide (DOTANOC) or DOTA- octreotide (DOTATOC).
131 I WBS (–) 18 FDG PET (–) ↑↑ Tg (56000 µg/L)
68 Ga DOTA-TATE PET/CT SCAN
Somatostatin receptor expression in thyroid CA Patients with positive studies may be treated with Peptide Receptor Radionuclide Therapy (PRRT) 117Lu DOTA-TATE 90Y DOTA-TATE
18 FDG Scan in Medullary TCA Intense FDG uptake in a hypodense nodule, L thyroid lobe Serum Calcitonin: 800 Final Diagnosis: Medullary TCA PET onlyCT Only PET-CT Fusion
Other findings in PET ↑ FDG uptake in thyroid nodule as part of whole body study for cancer imaging = moderately high risk of malignancy Require further evaluation Differentials = Graves' disease & thyroiditis Otherwise, thyroid gland should be normal in PET
Diffuse 18 FDG uptake (benign)
Philippine Data (2002 to 2012) FDG PET on 105 patients from 2005 to 2012 72 ♀ and 33 ♂ 17- to 83-years old Indications 116 – disease recurrence 6 – staging 11 – residuals 21 – response to therapy 13 – monitoring
Case Profile (Philippines) 77 – papillary thyroid cancer 9 – follicular thyroid cancer 11 – medullary thyroid cancer 2 – anaplastic thyroid cancer 2 – insular thyroid cancer 2 – squamous cell carcinoma 1 – adenosquamous thyroid carcinoma 1 – Castle disease
Results 32 PTCA + 4 FTCA ↑ Tg, (–) RAI scan, (+) 18 FDG PET 14 PTCA Normal Tg, (–) RAI scan, (+) 18 FDG PET Most frequent sites of metastases Neck area Cervical lymph nodes Pretracheal nodes Lungs
Results Most common resultant interventions: LN dissection Gamma knife therapy EBRT Chemotherapy ↑ dose RAI therapy
Advantages of PET/CT Can detect significantly more tumor sites Only imaging modality that can screen for malignancy in multiple organs at once Can lead to more appropriate clinical management
Other uses of 18 FDG PET Indeterminate thyroid nodules (3 cases) Calcitonin-positive medullary TCA 18 F-DOPA is superior to 18 FDG for this One case was negative on 18 FDG Anaplastic thyroid cancer Insular thyroid carcinoma
Summary of 18FDG PET Impact on Thyroid Cancer Management Determination of definitive therapy for RAI scan (–) WDTCA with elevated Tg Evaluation of aggressive and difficult-to-treat TCA and poorly differentiated TCA Discrimination of malignancy from thyroiditis in questionable thyroid nodules
Greatest impact of PET/CT For WDTCA whose I-131 WBS is negative with increasing thyroglobulin but positive in PET as therapy is more definitive For aggressive and difficult to treat TCA and undifferentiated TCA For questionable thyroid nodules differentiating malignancy and thyroiditis
Interesting Case CT (L) & fused PET/CT (R) in 56 y/o woman with lung cancer. Focal FDG uptake in R thyroid lobe with low CT attenuation (76 HU). PTCA on histopath.
Interesting Case CT (L) & fused PET/CT (R) in 65 y/o man with esophageal cancer. Focal FDG uptake in L thyroid lobe with very low CT attenuation (3.6 HU). Diffusely increased FDG uptake in surrounding gland tissue. Follicular adenoma with lymphocytic thyroiditis on histopath.
Interesting Case 63/M with PTCA, s/p thyroidectomy, RAI therapy, thoracotomy, and radiotherapy Neck MRI = L anterior neck nodule suspicious for recurrence (+) pulmonary nodules on CT Biopsy of thyroid & lung nodules = not malignant (+) RAI-avid right cervical lesion with elevated Tg
Interesting Case Calcified hypermetabolic R paratracheal node, multiple bilateral hypermetabolic non-calcified pulmonary nodules, multiple cervical, hilar and substernal nodes, and hypermetabolic lesions in a left rib and sternum, suspicious for metastases.
Interesting Case 65/F with PTCA, s/p thyroidectomy & multiple RAI therapies (cumulative dose = 1150 mCi) elevated Tg at >800 (+) nodules in both lungs and left adrenal (+) R lung base RAI-avid lesion on post- therapy whole body scan
Interesting Case Hypermetabolic right lung base mass corresponding to RAI-avid R lung base lesion seen on post-therapy scan, consistent with persistent metastatic thyroid cancer.
Interesting Case 67/F with PTCA, s/p thyroidectomy, L radical neck dissection, multiple RAI therapies & gamma knife treatment elevated Tg, (–) RAI whole body scan (+) nodules in both lungs and left adrenal (+) R lung base RAI-avid lesion on post- therapy whole body scan CT showed possible recurrence in L thyroid bed
Interesting Case FDG-avid right cavernous sinus mass involving the petrous part of the temporal bone is most likely metastatic in nature.
Interesting Case Hypermetabolic lesions/masses in the left neck extending to the thoracic inlet specifically to the left thyroid bed with hypermetabolic bilateral cervical lymphadenopathies are consistent with recurrent metastatic disease.
Interesting Case Hypermetabolic osseous metastases in the cervico thoracic spine.
Interesting Case 77/M with insular TCA, s/p thyroidectomy L thyroid nodule and lung nodules on pre-op CT Post-op PET was requested for evaluation of disease extent
Interesting Case Hypermetabolic lesion in the left thyroid bed may be inflammatory but residual disease cannot be ruled out.
Interesting Case Hypermetabolic R hilar nodes. Differentials include inflammatory reaction vs. metastases.
TCA Follow-up & Monitoring
Review of 2594 cases were reviewed for 1.5 years Focal and diffuse thyroid FDG uptake were identified and were correlated with patholological diagnosis 3.8% (99/2594) showed incidental thyroid FDG uptake 46 diffuse (21 chronic thyroiditis) 53 focal 11/53 with focal FDG uptake FNAB results 4 benign 7 malignant (63.3%) Use of SUV to delineate benign from malignant uptake is still undetermined Chen, et al. Evaluation of thyroid FDG uptake incidentally identified on FDG imaging. NMC 2009 March 30(3):240-4
Conclusions Ultrasound and thyroid scans are still the mainstay in imaging the thyroid gland CT and MRI have limited values and can be utilized in identifying lymph nodes, local tumor extension, diff. thyroiditis and as FNA guide PET/CT is best for WDTCA that have dedifferentiated hence negative on I-131- WBS but increasing thyroglobulin as well as in aggressive and difficult cases of TCA and certain suspicious nodules by FNAB