Our Initial Experience of the Utility of Hybrid SPECT/CT in the Follow-up of Patients with Thyroid Carcinoma
PURPOSE: Our first hybrid SPECT/CT was just recently installed. A retrospect study was done to determine the diagnostic impact of our initial cases of 131I-SPECT/CT imaging compared with conventional planar scintigraphic evaluation in the follow-up of patients with thyroid carcinoma.
METHODS: We retrospectively evaluated the first ten patients with thyroid carcinoma who were imaged with hybrid SPECT/CT, in order to evaluate precisely foci of anatomically indeterminate uptake which were detected on planar 131I whole-body images.
RESULTS: SPECT/CT imaging had an incremental diagnostic value in 100% (10/10) of patients and all the total of 13 foci of interest in this study. For the various indeterminate uptake seen on planar 131I whole-body images, five foci of periodontal diseases were precisely determined; three foci were localized at nasal mucosa and/or nasal cavity; three foci were precisely localized as bony metastases; one focus was definitely determined to be in gallbladder with lithiasis and chronic cholecystitis and one focus of neck uptake was correctly characterized as lymphnode metastasis.
CONCLUSION: Owing to a lack of anatomical landmarks and inadequate physiological distribution of the 131I tracer, precise localization of abnormalities on 131I planar scintigraphy can be difficult. Hybrid SPECT/CT was definitely helpful for correct characterization of uptake seen on planar imaging as well as for precise localization of malignant lesions in the skeletal system. In addition, there is a further clinical impact on patient management for necessity of 131I treatment, the optimal administered radioiodine dose, and/or the addition of surgery or external radiation therapy when clinically indicated.