Postoperative Surveillance of Differentiated Thyroid Carcinoma: Rationale, Techniques, and Controversies
Flip-flop phenomenon in differentiated thyroid carcinoma (DTC), whereby less differentiated tumors downregulate sodium-iodide symporter production (manifesting as loss of radioiodine avidity) and increase glucose transporter-1 expression (manifesting as PET scan positivity).
(a) Diagnostic WBS image shows no abnormal 131I uptake. (b) PET scan obtained two days later shows extensive cervical and mediastinal metastases (arrows).
(Radiology 2008; 248:429–444) © RSNA, 2008. All rights reserved. Printed with permission.
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The majority of differentiated thyroid carcinomas (DTCs) are cured by means of surgical resection and radioiodine therapy. Although DTC is typically an indolent tumor, current surveillance strategies are imaging intensive because of the high likelihood of local-regional recurrence in the thyroid bed and the cervical nodal chains.
In a review article in the November issue of Radiology (RSNA.org/radiology), Nathan A. Johnson, M.D., and Mitchell E. Tublin, M.D., detail the accepted surveillance and treatment strategies for DTC recurrence. The authors, both of the University of Pittsburgh Medical Center, specifically address the utility of the following in identifying local and disseminated disease:
• 131I whole-body scintigraphy (WBS)
• Neck ultrasound
• MR imaging
• CT
• Fluorine 18 (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET)
• Coregistered CT/PET
Drs. Johnson and Tublin also discuss recent advances in the understanding of the molecular biology of DTC, as these advances will likely influence how patients are treated and followed up in the near future. "The appropriate intensity of surveillance strategies and the aggressiveness of surgical and radioiodine management of small-volume recurrence continues to evolve," they conclude. "Recent advances in our understanding of tumor biology may ultimately allow more appropriate risk stratification and tailored imaging surveillance protocols and treatment of patients with DTC."
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This article meets the criteria for 1.0 AMA PRA Category 1 Credit™. CME is available online only.
Multidetector CT of Aortic Stent-Grafts with 2D Multiplanar Reformation and 3D Rendering: Utility for Pre- and Postprocedure Evaluation of Stents in the Thoracic Aorta
Advances in multidetector CT permit the high-quality 2D multiplanar reformation and 3D rendering essential for comprehensive assessment of the thoracic aorta. The ability of multidetector CT to allow detailed evaluation in any plane or perspective enables detection of thoracic aortic disease and assessment of its relationship to normal vessels.
Aortic aneurysm in a 78-year-old man.
(a) Sagittal color-coded 3D volume-rendered image from contrast-enhanced CT shows an atherosclerotic aneurysm of the thoracic aorta. The aneurysm was successfully treated with an endovascular stent (arrow). This view allows assessment of luminal patency and shows no evidence of contrast material extravasation. (b) Sagittal volume-rendered image, created after removal of internal blood from the dataset, shows only the stent (arrow).
(RadioGraphics 2008;28:1835-1851) © RSNA, 2008. All rights reserved. Printed with permission.
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In an article in the November-December issue of RadioGraphics (RSNA.org/radiographics), Marchelle J. Bean, M.D., of Johns Hopkins Medical Institutions, and colleagues detail the information required by referring clinicians before placement of thoracic aortic stent-grafts. The authors also discuss important multidetector CT findings after placement and list potential complications.
Specifically, Dr. Bean and colleagues address:
• Multidetector CT technique
• Pathologic conditions amenable to endovascular stent placement
• Assessment before stent placement
• Stent placement and outcomes
• Follow-up after stent placement
• Efficacy
• Complications such endoleaks, pseudoaneurysm and aortic perforation
"Radiologists must be able to not only detect pathologic conditions of the thoracic aorta but also provide the referring clinician with the necessary pre- and post-procedure information to determine appropriate clinical care," the authors write.
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