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.

Introduction: Integration of single photon emission computed tomography (SPECT) and computed tomography (CT) scanners into SPECT/CT hybrid systems permit detection of coronary artery disease in myocardial perfusion imaging (MPI). Misregistration between CT and emission data can produce some errors in uptake value of SPECT images. The aim of this study was evaluate the influence of attenuation correction (AC) versus non-attenuation correction (NC) images and the effect of misregistration on all segments of SPECT images for quantitative and qualitative analysis. Methods: 99 patients (45 males, 54 females) underwent stress/rest myocardial perfusion imaging (MPI) using 99mTc-MIBI were used in this study. We also utilized cardiac insert and lung insert in cylinder phantom. Phantom studies were performed with and without defect. The misregistration of all patient data was measured and variation in misregistration of our population was recorded. The effect of attenuation correction (AC) and non-attenuation correction (NC) images were also evaluated in both phantom and patient data. The CT images were shifted by ± 1, ± 2, ± 3 pixels along X-, Y-and Z-axis (Left/right, dorsal/ventral, cephalic/caudal) for both phantom and patient studies. Differences between misalignment data and misregistration correction images were also measured. Results displayed with 20 segments polar map analysis and illustration in standard orientations for cardiac tomographic images. Results: In the patient population data, 1. 5% were perfectly registered, 17% and 73% misaligned under 1 pixel and more than 1 pixel, reSPECTively. AC of SPECT images showed increased uptake value in normal phantom and false positives findings were disappeared versus to NC images. In patient data, statistically significant variation were shown for the most segments before and after AC (P-value<=0. 004) and also between AC of SPECT image and misregistration correction images (P-value<=0. 048). Along X-axis, in 3 pixel shift in right direction, the percent of relative difference in lateral wall were 11. 94% for mid anterolateral. Along Y-axis, the Ventral shift caused-15. 9% changes in basal inferolateral and along Z-axis-8. 59 % changes in apical anterolateral were also observed in caudal direction when 3 pixel shifts were used. Conclusion: This study showed that CT-based attenuation correction of cardiac images in hybrid SPECT/CT is important to improve image quality. Misalignment in caudal, cephalad, ventral and right direction introduced significant variation even in 1 pixel shift. It is important to apply misregistration correction even in small misalignment routinely in clinical myocardial perfusion imaging.

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.

A 67 years old woman was referred to nuclear medicine center for myocardial perfusion imaging (MPI) for assessment of ischemic heart dieses (IHD). She had a history of atypical chest pain and dyspnea since about 10 days before admission. The MPI SPECT/CT was performed by stress/redistribution Tl-201 protocol. MPI was interpreted as relatively good coronary flow with no appreciable stress induced ischemia. SPECT-CT images revealed multifocal, bilateral and peripheral ground-glass opacities in lungs with subtle background uptake of Tl-201. Considering Covid-19 outbreak, the first diagnosis based on chest CT was Covid-19. This case emphasizing importance of attention to non-cardiac findings in patients undergoing myocardial perfusion imaging, especially review of lung window images in SPECT/CT protocols in the era of covid-19.

Background: Fibrous dysplasia is a rare benign bone disorder characterized by the fibrous tissue containing trabeculae of non-lamellar bone (woven bone) and occupying normal medullary spaces. The uptake of the radiotracer in the affected bone is variable, and specificity is too low to diagnose fibrous dysplasia in the bone scan. Materials and Methods: We are presenting four cases with monostotic fibrous dysplasia which were detected incidentally on the routine planar bone scan while being investigated for a metastatic cancer work-up. During a cancer work-up at our institution, we find lesions of fibrous dysplasia showing significantly increased uptake on the bone scan which may mimic metastatic bone lesions. Results: The SPECT/CT increases diagnostic confidence and improves accuracy and specificity of a planar bone scan. These cases were all asymptomatic at the one-year follow-up The subsequent bone scan and radiography studies have revealed no progression of these bone lesions. Conclusion: The SPECT/CT images increase the diagnostic accuracy of the bone scan, which may avoid unnecessary surgery or overtreatment of fibrous dysplasia as bone metastasis. Abbreviation: SPECT/ CT = single photon emission computed tomography/computed tomography.