Management of hirsutism

1262 Objectives: The combination of SPECT and spiral-CT in hybrid cameras offers the unique opportunity to register molecular information provided by SPECT to morphology. With this technology, the scanning area of the CT can be restricted to the area with abnormal findings on SPECT (SPECT-guided CT). The aim of the present study was to determine the value of this technique in patients with thyroid cancer exhibiting indeterminate lesions in I-131-whole-body scintigraphy. Methods: From March to December 2005, in our clinic, 150 patients with differentiated thyroid cancer had I-131-whole-body scans either for restaging or after ablative radioiodine therapy. Out of these, 25 were referred to SPECT/spiral-CT (Symbia T2; Siemens Medical Solutions) in order to evaluate areas with abnormal radioiodine uptake on the planar whole-body scintigraphy. Afterwards, the planar scans as well as the SPECT/CT images of these patients were retrospectively analyzed using the following 3-point-scale: 1, definitely benign; 2, indeterminate; 3, definitely malignant or clear residual thyroid tissue. Results: In total, 40 findings were described on the whole-body scintigraphies; 23 were classified as indeterminate and 17 as definitely malignant. Out of the 23 indeterminate findings, 16 findings corresponded to physiological uptake in the salivary glands, the esophagus or the bowel. Five findings correlated with residual thyroid tissue; one lesion corresponded to a bone metastasis in the lumbar spine and one lesion remained indeterminate also after the analysis of SPECT/CT. Ten out of the 17 findings classified as definitely malignant on planar whole-body scintigraphy were correlated with pathologic findings on CT. Out of five lesions classified as definitely malignant cervical or periclavicular lymph nodes, three corresponded to residual thyroid tissue or lobus pyramidalis, the remaining two had no pathological correlate and were classified as negative. In one case, SPECT/CT allowed for classification as superficial contamination. One lesion originally found to be definitely malignant on planar whole-body scintigraphy had to be classified as indeterminate after the analysis of SPECT/CT. Conclusions: SPECT-guided CT is able to clarify more than 90 % of findings with abnormal radioiodine uptake I-131-whole-body scintigraphy. Furthermore, SPECT/CT had an incremental diagnostic value in 21 out of 25 patients (84%). Research Support (if any): Siemens Medical Solutions, business unit Molecular Imaging Europe, kindly provided the Symbia T2 SPECT/CT scanner used herein.