Planar 131 I scintigraphy is routinely used to detect radioiodineavid metastases of differentiated thyroid carcinoma (DTC). However, the modality has limitations, such as low sensitivity and lack of anatomic landmarks. We investigated whether SPECT with integrated low-dose CT may have additional value over planar imaging in detecting residue and metastases in DTC patients. Methods: We studied 117 consecutive thyroidectomized DTC patients. On 2 different hybrid dual-head g-cameras (55 patients on one camera and 62 on the other), 108 patients underwent 131 I diagnostic imaging and SPECT/ CT, and 9 underwent posttherapeutic 131 I planar imaging and SPECT/CT. We assigned an incremental value to SPECT/CT when it provided better identification and interpretation of the foci of radioiodine uptake, more correct anatomic localization and characterization, and precise differentiation between tumor lesions and physiologic uptake. Results: Planar imaging showed 116 foci of uptake in 52 of 117 patients, and SPECT/CT showed 158 foci in 59 of 117 patients, confirming all foci seen on planar imaging but identifying an additional 28 occult foci in 10 of 52 patients. Fourteen occult foci were shown on SPECT/CT in 7 further patients whose planar imaging findings were negative. SPECT/ CT correctly characterized 48 foci unclear on planar imaging, also defining location and extent. SPECT/CT was a determinant in classifying as neoplastic those foci for which planar imaging seemed to exclude malignancy, discriminating between residue and lymph node metastases in the neck, some of which were adjacent to salivary glands and had been missed on planar imaging. SPECT/CT also showed occult lesions in the mediastinum, abdomen, and pelvis and identified small bone metastases unsuspected on planar imaging. Globally, SPECT/CT had an incremental value over planar imaging in 67.8% of patients, modified therapeutic management in 35.6% of positive cases, and avoided unnecessary treatment in 20.3% of patients with only single benign lesions or physiologic uptake. Conclusion: 131 I SPECT/CT improved planar data interpretation, showing a higher number of DTC lesions, more precisely localizing and characterizing DTC foci, and more correctly differentiating between physiologic uptake and metastases, thus permitting the most appropriate therapeutic approach to be chosen. A wider use of this method is suggested complementary to planar imaging in selected DTC patients. Convent ional planar 131 I whole-body scintigraphy, in association with serum thyroglobulin measurement, is still considered the routine diagnostic procedure in patients with well-differentiated thyroid carcinoma (DTC). This modality is used in the detection of both thyroid tissue residue and local and distant metastases, after thyroidectomy for staging and after radioiodine ablation for restaging and long-term follow-up (1). A sensitivity of 45%275% and a specificity of 90%2100% have been reported in the literature for diagnostic planar 131 I whole-body imaging in detecting recurrences or me...

HAART, particularly stavudine, is associated with a high prevalence of subclinical hypothyroidism. Hypotheses are made regarding responsible mechanisms and risk factors. Thyroid function should be tested and sequentially rechecked in HAART patients.

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Papillary thyroid microcarcinoma (PTMC) usually has a favorable prognosis but can also be aggressive, with neck and distant metastases. We evaluated the diagnostic role of I SPECT/CT in detecting metastases in PTMC patients during long-term follow-up and whether the procedure should be included in the current diagnostic protocol. We retrospectively studied 351 consecutive PTMC patients who had undergone thyroidectomy and radioiodine therapy; 21 were at high risk, 94 at low risk, and 236 at very low risk. During follow-up, the patients underwent diagnostic I whole-body scanning (WBS) followed by SPECT/CT. WBS found 248 radioiodine-avid foci in 126 patients, and SPECT/CT found 298 in 139 patients, confirming all foci found on WBS. SPECT/CT also correctly classified 76 of the avid foci as unclear or wrongly classified on WBS. Globally, SPECT/CT detected and correctly classified 64 neoplastic lesions in 27 of 30 patients with metastases, and WBS evidenced 39 of 64 lesions, 28 of which were unclear or wrongly classified, in 16 of the 30 patients. Nineteen of 27 patients, including 13 at very low risk, had only neck metastases, 9 of 19 being T1aN0M0 with an undetectable thyroglobulin level. Three of 27 patients, including 1 at very low risk, had only distant metastases with an undetectable or very low thyroglobulin level. Five of 27 patients had neck and distant metastases with a thyroglobulin level <2.5 ng/mL in 1 case, between 2.5 and 10 in 3 cases, and >10 in the remaining case. SPECT/CT also reduced WBS false-positive results in 15 of 139 patients (10.8%). SPECT/CT had an incremental value over WBS in 38.1% of patients with positive findings and changed the classification and therapeutic management in 21.6%. Metastases occurred in 8.5% of patients during long-term follow-up. SPECT/CT performed better than WBS, particularly in patients at very low risk with inconclusive WBS results, a TNM stage of T1aN0M0, and an undetectable or very low level of thyroglobulin. Prolonged surveillance is justified in PTMC patients, and wider use ofI SPECT/CT in the diagnostic protocol is suggested.

The aim of this study was to assess the usefulness of planar scintimammography (SM) with a high-resolution dedicated breast camera (DBC) compared to SPECT in unifocal and multifocal/multicentric primary breast cancer (BC) detection. DBC planar SM and conventional SPECT were acquired using 99m Tc-tetrofosmin as radiotracer in 85 consecutive patients suspect for BC at conventional imaging and clinical examination. Scintigraphic data were related to histology in all cases. BC was proven in 74/85 patients, unifocal in 56/74 cases and multifocal/multicentric in 18/74; 90 carcinomas were ascertained. Benign lesions were found in 12 cases, including one who also had BC in the contralateral breast. DBC planar SM and SPECT were true-positive in 72/74 and in 70/74 BC patients, respectively, and globally detected 96.7% and 92.2% of carcinomas. DBC and SPECT sensitivity were, respectively, 90.3% and 80.6% in ≤10-mm carcinomas and 100% and 98.3% in larger ones; sensitivity values in non-palpable carcinomas were 92.6% and 77.8%, respectively, and 98% for both procedures in palpable ones. DBC planar SM and SPECT correctly assessed multifocality/ multicentricity in 91.7% and 83.3% of cases, respectively. Sensitivity differences were not significant. Both procedures showed only a false-positive result. DBC planar SM and SPECT proved highly sensitive and specific in BC detection, representing a useful complementary tool to mammography. However, DBC planar SM showed technical advantages and better clinical performance than SPECT in both subcentrimetric carcinoma detection and multifocal/multicentric disease assessment. Thus, DBC planar SM should be preferred, but SPECT remains a useful alternative when DBC is unavailable.