ATA Guidelines Tools

25 67. A) Diagnostic WBS, either following thyroid hormone withdrawal or rhTSH, 6–12 months after remnant ablation adjuvant RAI therapy can be useful in the follow-up of patients with high or intermediate risk (higher risk features) of persistent disease and should be done with 123 I or low activity 131 I. (SR-L) B) SPECT-CT radioiodine imaging is preferred over planar imaging in patients with uptake on planar imaging to better anatomically localize the radioiodine uptake and distinguish between likely tumors and nonspecific uptake. (WR-M) 68. A) 18 FDG-PET scanning should be considered in high risk DTC patients with elevated serum Tg (generally >10 ng/ml) with negative radioiodine imaging. (SR-M) B) 18 FDG-PET scanning may also be considered a) as part of initial staging in poorly differentiated thyroid cancers and invasive Hürthle cell carcinomas, especially those with other evidence of disease on imaging or because of elevated serum Tg levels, b) as a prognostic tool in patients with metastatic disease to identify lesions and patients at highest risk for rapid disease progression and disease-specific mortality, and c) as an evaluation of posttreatment response following systemic or local therapy of metastatic or locally invasive disease. (WR-L) 69. A) Cross-sectional imaging of the neck and upper chest (CT, MRI) with intravenous contrast should be considered a) in the setting of bulky and widely distributed recurrent nodal disease where ultrasound may not completely delineate disease, b) in the assessment of possible invasive recurrent disease where potential aerodigestive tract invasion requires complete assessment or c) when neck ultrasound is felt to be inadequately visualizing possible neck nodal disease (high Tg, negative neck US). (SR-M). B) CT imaging of the chest without intravenous contrast (imaging pulmonary parenchyma) or with intravenous contrast (to include the mediastinum) should be considered in high risk DTC patients with elevated serum Tg (generally >10 ng/ml) or rising Tg antibodies with or without negative radioiodine imaging (SR-M) C) Imaging of other organs including MRI brain, MR skeletal survey, and/or CT or MRI of the abdomen should be considered in high risk DTC patients with elevated serum Tg (generally >10 ng/ml) and negative neck and chest imaging, who have symptoms referable to those organs, or who are being prepared for TSH-stimulated RAI therapy (withdrawal or rhTSH) and may be at risk for complications of tumor swelling (SR-L)

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