Contrast is not contraindicated for DTC based on new studies on iodine retention [11,12] (see Special Imaging Considerations section above). Dual-phase CT imaging with and without IV contrast does not provide any additional information. MRI Neck MRI of the neck and mediastinum has the same role as CT in evaluating sites that are limited on US. The performance of MRI for imaging the neck and mediastinum has not been directly compared with CT on large numbers of thyroid cancer patients. Contrast is valuable for local staging and assessing suspicious lymph nodes. MRI has disadvantages of motion artifact in the lower neck from respiration and swallowing and is less sensitive than CT scan for the detection of small pulmonary nodules. FDG-PET/CT Whole Body A small prospective study compared diagnostic accuracy of FDG-PET/CT with US and contrast-enhanced CT. The sensitivity of PET for the detection of cervical lymph node metastases at all nodal levels is lowest for PET (30% versus 41% for US and 35% for CT) [35]. In general, because of the low avidity of well-differentiated thyroid cancers, FDG-PET/CT is not useful. Sensitivity of FDG-PET/CT scanning for malignancy may be slightly increased with TSH stimulation with recombinant human TSH but not enough to change management in most patients [36]. Whole-Body Scintigraphy Whole-body scintigraphy (WBS) has no role in the preoperative staging for DTC since the normal thyroid has very high iodine uptake and will take up most of the tracer. Octreotide Scan with SPECT or SPECT/CT Chest and Abdomen There is no role for indium-111 (In-111) somatostatin receptor scintigraphy at any stage of evaluation of DTC. Variant 6: Early imaging after treatment of thyroid cancer. After surgery, an early postoperative US within 6 to 12 months should be performed on all patients. Additional imaging depends on the extent of disease and surgery.
Thyroid Disease. Contrast is not contraindicated for DTC based on new studies on iodine retention [11,12] (see Special Imaging Considerations section above). Dual-phase CT imaging with and without IV contrast does not provide any additional information. MRI Neck MRI of the neck and mediastinum has the same role as CT in evaluating sites that are limited on US. The performance of MRI for imaging the neck and mediastinum has not been directly compared with CT on large numbers of thyroid cancer patients. Contrast is valuable for local staging and assessing suspicious lymph nodes. MRI has disadvantages of motion artifact in the lower neck from respiration and swallowing and is less sensitive than CT scan for the detection of small pulmonary nodules. FDG-PET/CT Whole Body A small prospective study compared diagnostic accuracy of FDG-PET/CT with US and contrast-enhanced CT. The sensitivity of PET for the detection of cervical lymph node metastases at all nodal levels is lowest for PET (30% versus 41% for US and 35% for CT) [35]. In general, because of the low avidity of well-differentiated thyroid cancers, FDG-PET/CT is not useful. Sensitivity of FDG-PET/CT scanning for malignancy may be slightly increased with TSH stimulation with recombinant human TSH but not enough to change management in most patients [36]. Whole-Body Scintigraphy Whole-body scintigraphy (WBS) has no role in the preoperative staging for DTC since the normal thyroid has very high iodine uptake and will take up most of the tracer. Octreotide Scan with SPECT or SPECT/CT Chest and Abdomen There is no role for indium-111 (In-111) somatostatin receptor scintigraphy at any stage of evaluation of DTC. Variant 6: Early imaging after treatment of thyroid cancer. After surgery, an early postoperative US within 6 to 12 months should be performed on all patients. Additional imaging depends on the extent of disease and surgery.