Introduction: Primary hyperparathyroidism is the most common cause of hyperparathyroidism and hypercalcemia, and the treatment is mainly surgical. Planning for focused surgical parathyroidectomy or minimally invasive parathyroidectomy requires precise preoperative localization of parathyroid lesions in patients with hyperparathyroidism. The purpose of this study is to evaluate reliability in correctly detecting parathyroid lesions by SPECT-CT, SPECT and planar 99mTc-Sestamibi imaging.Methods: 65 patients with primary hyperparathyroidism were enrolled in this study. All patients underwent planar and SPECT-CT before surgery. Planar imaging was performed at 20 minutes and 2 hours after injection. SPECT as well as combined non-contrast-enhanced low dose CT scan using a hybrid SPECT-CT instrument were also obtained immediately after early phase planar scintigraphy. Three image sets (early and delayed planar images, SPECT, and SPECT-CT) were reviewed for parathyroid lesion localization separately.Surgical location and histopathologic findings were used as the standard. Sensitivity and positive predictive value were determined for each method.Results: In all patients (5 cases with multiple endocrine neoplasia), surgery was done successfully. Totally, 72 parathyroid lesions (70 adenomas and 2 hyperplasia) were dissected. Solitary parathyroid adenoma, double parathyroid adenomas, and double hyperplastic parathyroid glands were found in 60, 5, and 1 patients, reSPECTively. Planar images showed correct localization of lesions only in 36 cases, with low sensitivity (63%) and positive predictive value (69%) in comparison with other image sets. Sensitivity of SPECT-CT (88%) was significantly greater than SPECT (72%) (p>0.001). Positive predictive value of SPECT- CT (92%) was also greater than SPECT (80%) (p>0.001). SPECT-CT was markedly superior to planar images and SPECT in patients with ectopic adenomas.Conclusion: In patients with primary hyperparathyroidism preoperative SPECT-CT is a reliable method for parathyroid lesion localization, and is also helpful in surgical planning for parathyroidectomy.

Different software tools for quantification of myocardial perfusion SPECT (MPS) studies are routinely used. Several perfusion parameters can be computed automatically. Interpretation of the MPS should start with visual inSPECTion of the rotating planar images, visual analysis of reconstructed SPECT slices and then quantitative analysis to confirm the visual impression. Quantification should be used routinely as complementary to visual analysis. Advantages of quantification are: greater confidence in interpretation, better reproducibility, diagnostic accuracy and measuring the degree of abnormality even subtle changes for serial comparisons. In this review, we look at the common features of such quantitative tools: 17- segment scoring system, polar maps including: raw, severity and extent polar maps, lung-to-heart ratio, transient ischemic dilation ratio, total perfusion deficit and spherecity index.

Background: We evaluated the efficacy of 99mTcsestamibi SPECT/CT for planning minimally invasive parathyroidectomy (MIP), comparing with dual phase 99mTc-sestamibi scintigraphy, 99mTc-sestamibi SPECT and conventional imaging (US and CT).Materials and Methods: Thirty-one patients (M: F=10: 21, range 35–78 years old) who showed high serum parathyroid hormone (intact PTH) level were included.99mTc-sestamibi scintigraphy was performed 15 and 150 min after injection of 99mTcsestamibi (555 MBq), and 99mTc-sestamibi SPECT/CT was obtained just after the delayed scan. Comparison study between imaging modalities was done by patient-based and lesion location-based analysis.The location of the lesion was confirmed by the operative finding. An operation was performed in 24 patients. Seven patients had normal 99mTc-sestamibi SPECT/CT, and followed for more than 6 months after SPECT/CT.Results: Among 24 patients, parathyroid adenoma was detected in 19 patients and the other 5 had parathyroid hyperplasia (total 35 lesions).99mTcsestamibi scintigraphy detected abnormal uptake in 15 patients with 24 lesions. Conventional imaging identified abnormal findings in 17 patients with 27 lesions. SPECT detected abnormal findings in 18 patients with 27 lesions. SPECT/CT identified abnormal findings in 24 patients with 35 lesions.SPECT/CT demonstrated 100 % sensitivity in a patient-based analysis. SPECT/CT exhibited significantly better sensitivity than 99mTc-sestamibi scintigraphy, SPECT and conventional imaging (p\0.05). All lesion location was correctly identified to perform MIP. The final clinical diagnosis of 7 normal SPECT/CT patients was secondary hyperparathyroidism on 6 months follow-up.Conclusion: We correctly identified the precise location of parathyroid adenomas or hyperplasia by 99mTc-sestamibi SPECT/CT which was helpful to perform MIP.

Objective(s): In this study, we aimed to analyze the relationship between the diagnostic ability of fused single photon emission computed tomography/computed tomography (SPECT/CT) images in localization of parathyroid lesions and the size of adenomas or hyperplastic glands.Methods: Five patients with primary hyperparathyroidism (PHPT) and 4 patients with secondary hyperparathyroidism (SHPT) were imaged 15 and 120 minutes after the intravenous injection of technetium99mmethoxyisobutylisonitrile (99mTc-MIBI). All patients underwent surgery and 5 parathyroid adenomas and 10 hyperplastic glands were detected. Pathologic findings were correlated with imaging results.Results: The SPECT/CT fusion images were able to detect all parathyroid adenomas even with the greatest axial diameter of 0.6 cm. Planar scintigraphy and SPECT imaging could not detect parathyroid adenomas with an axial diameter of 1.0 to 1.2 cm. Four out of 10 (40%) hyperplastic parathyroid glands were diagnosed, using planar and SPECT imaging and 5 out of 10 (50%) hyperplastic parathyroid glands were localized, using SPECT/CT fusion images.Conclusion: SPECT/CT fusion imaging is a more useful tool for localization of parathyroid lesions, particularly parathyroid adenomas, in comparison with planar and or SPECT imaging.