Usefulness of the automatic quantitative estimation tool for cerebral blood flow: clinical assessment of the application software tool AQCEL.

OBJECTIVE: AQCEL enables automatic reconstruction of single-photon emission computed tomogram (SPECT) without image degradation and quantitative analysis of cerebral blood flow (CBF) after the input of simple parameters. We ascertained the usefulness and quality of images obtained by the application software AQCEL in clinical practice. METHODS: Twelve patients underwent brain perfusion SPECT using technetium-99m ethyl cysteinate dimer at rest and after acetazolamide (ACZ) loading. Images reconstructed using AQCEL were compared with those reconstructed using conventional filtered back projection (FBP) method for qualitative estimation. Two experienced nuclear medicine physicians interpreted the image quality using the following visual scores: 0, same; 1, slightly superior; 2, superior. For quantitative estimation, the mean CBF values of the normal hemisphere of the 12 patients using ACZ calculated by the AQCEL method were compared with those calculated by the conventional method. The CBF values of the 24 regions of the 3-dimensional stereotaxic region of interest template (3DSRT) calculated by the AQCEL method at rest and after ACZ loading were compared to those calculated by the conventional method. RESULTS: No significant qualitative difference was observed between the AQCEL and conventional FBP methods in the rest study. The average score by the AQCEL method was 0.25 ± 0.45 and that by the conventional method was 0.17 ± 0.39 (P = 0.34). There was a significant qualitative difference between the AQCEL and conventional methods in the ACZ loading study. The average score for AQCEL was 0.83 ± 0.58 and that for the conventional method was 0.08 ± 0.29 (P = 0.003). During quantitative estimation using ACZ, the mean CBF values of 12 patients calculated by the AQCEL method were 3-8% higher than those calculated by the conventional method. The square of the correlation coefficient between these methods was 0.995. While comparing the 24 3DSRT regions of 12 patients, the squares of the correlation coefficient between AQCEL and conventional methods were 0.973 and 0.986 for the normal and affected sides at rest, respectively, and 0.977 and 0.984 for the normal and affected sides after ACZ loading, respectively. CONCLUSIONS: The quality of images reconstructed using the application software AQCEL were superior to that obtained using conventional method after ACZ loading, and high correlations were shown in quantity at rest and after ACZ loading. This software can be applied to clinical practice and is a useful tool for improvement of reproducibility and throughput.

Semiquantitative measurement of pulmonary hilar gallium-67 uptake using single photon emission computed tomography/computed tomography for the diagnosis of autoimmune pancreatitis.

PURPOSE: We ascertained the difference in the level of pulmonary hilar (PH) gallium-67 (Ga-67) uptake in autoimmune pancreatitis (AIP) patients between the active (before corticosteroid therapy) and remittent (after 4 weeks of corticosteroid therapy) phases using a semiquantitative measurement method based on single photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT). MATERIALS AND METHODS: Ga-67 planar scans and SPECT were performed in 11 AIP patients before and after 4 weeks of corticosteroid therapy. A region of interest (ROI) was drawn over the bilateral pulmonary hilum and the liver, and average counts of the pulmonary hilum and liver were calculated. The average counts of the pulmonary hilum divided by those of the liver gave the pulmonary hilum/liver ratio (H/L). RESULTS: A significant difference was observed in the H/L between active and remittent phases. H/L in the active phase was 1.03±0.32 and that in the remittent phase was 0.58±0.25 (t-test, P=0.0016). CONCLUSIONS: PH Ga-67 uptake in patients with active AIP was semiquantitatively higher than that in those with remittent AIP. Hence, this may be a useful finding for an early diagnosis, estimating the effectiveness of corticosteroid therapy, and following up patients with this disease.

Characteristic findings in images of extra-pancreatic lesions associated with autoimmune pancreatitis.

PURPOSE: Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by a variety of extra-pancreatic involvements which are frequently misdiagnosed as lesions of corresponding organs. The purpose of this study was to clarify the diagnostic imaging features of extra-pancreatic lesions associated with autoimmune pancreatitis. MATERIALS AND METHODS: We retrospectively analyzed diagnostic images of 90 patients with autoimmune pancreatitis who underwent computer-assisted tomography, magnetic resonance imaging, and/or gallium-67 scintigraphy before steroid therapy was initiated. RESULTS: AIP was frequently (92.2%) accompanied by a variety of extra-pancreatic lesions, including swelling of lachrymal and salivary gland lesions (47.5%), lung hilar lymphadenopathy (78.3%), a variety of lung lesions (51.2%), wall thickening of bile ducts (77.8%), peri-pancreatic or para-aortic lymphadenopathy (56.0%), retroperitoneal fibrosis (19.8%), a variety of renal lesions (14.4%), and mass lesions of the ligamentum teres (2.2%). Characteristic findings in CT and MRI included lymphadenopathies of the hilar, peri-pancreatic, and para-aortic regions; wall thickening of the bile duct; and soft tissue masses in the kidney, ureters, aorta, paravertebral region, ligamentum teres, and orbit. CONCLUSIONS: Recognition of the diagnostic features in the images of various involved organs will assist in the diagnosis of autoimmune pancreatitis and in differential diagnoses between autoimmune pancreatitis-associated extra-pancreatic lesions and lesions due to other pathologies.

Lymphoscintigraphy using technetium-99m HSA-DTPA with SPECT/CT in chylothorax after childbirth.

Technetium-99m human serum albumin diethylene-triaminepentaacetic acid (HSA-DTPA) lymphoscintigraphy with single photon emission computed tomography combined with integrated low-dose computed tomography (SPECT/CT) is useful for evaluating chylothorax. We report a case of chylothorax that occurred 2 months after childbirth in a 24-year-old woman. Lymphoscintigraphy with SPECT/CT showed abnormal tracer accumulation in the right plural effusion, and chylothorax was diagnosed. Collateral branches of the thoracic duct were found to be ruptured during video-assisted thoracoscopic surgery performed for ligation.

Differentiation of autoimmune pancreatitis from suspected pancreatic cancer by fluorine-18 fluorodeoxyglucose positron emission tomography.

BACKGROUND: Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) has been widely used for the diagnosis of pancreatic cancer. Because autoimmune pancreatitis is easily misdiagnosed as pancreatic cancer and can be tested for by FDG-PET analysis based on the presence of suspected pancreatic cancer, we attempted to clarify the differences in FDG-PET findings between the two conditions. METHODS: We compared FDG-PET findings between 15 patients with autoimmune pancreatitis and 26 patients with pancreatic cancer. The findings were evaluated visually or semiquantitatively using the maximum standardized uptake value and the accumulation pattern of FDG. RESULTS: FDG uptake was found in all 15 patients with autoimmune pancreatitis, whereas it was found in 19 of 26 patients (73.1%) with pancreatic cancer. An accumulation pattern characterized by nodular shapes was significantly more frequent in pancreatic cancer, whereas a longitudinal shape indicated autoimmune pancreatitis. Heterogeneous accumulation was found in almost all cases of autoimmune pancreatitis, whereas homogeneous accumulation was found in pancreatic cancer. Significantly more cases of pancreatic cancer showed solitary localization, whereas multiple localization in the pancreas favored the presence of autoimmune pancreatitis. FDG uptake by the hilar lymph node was significantly more frequent in autoimmune pancreatitis than in pancreatic cancer, and uptake by the lachrymal gland, salivary gland, biliary duct, retroperitoneal space, and prostate were seen only in autoimmune pancreatitis. CONCLUSIONS: FDG-PET is a useful tool for differentiating autoimmune pancreatitis from suspected pancreatic cancer, if the accumulation pattern and extrapancreatic involvement are considered. IgG4 measurement and other current image tests can further confirm the diagnosis.

Usefulness of 67Ga SPECT and integrated low-dose CT scanning (SPECT/CT) in the diagnosis of cardiac sarcoidosis.

OBJECTIVE: We performed 67Gallium (Ga) single-photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT) for the interpretation of myocardial outline to investigate the value of co-registered fusion imaging using a hybrid system (SPECT/CT) in patients with cardiac sarcoidosis. METHODS: SPECT/CT of the region in question was performed with VG Hawkeye. The subjects in this study were 37 patients [mean (+/-SD) age 61.0+/-13.0 years; 12 men and 25 women], 13 of whom had a clinical diagnosis of cardiac sarcoidosis and 24 a negative diagnosis. An intravenous injection of Ga (dosage 111 MBq) was performed on patients 48 h or 72 h before obtaining static planar images of the whole-body and the SPECT/CT scan. RESULTS: Abnormal Ga uptake in the myocardium was observed in 10 of the 13 subjects with true sarcoidosis, and in 11 of 24 with negative sarcoidosis without CT fusion. The sensitivity without CT fusion was 77%, the specificity 54%, and the accuracy 62%. Use of SPECT/CT changed the diagnosis only in a patient with true sarcoidosis, and changed the diagnosis in eight patients with negative sarcoidosis. The sensitivity with CT fusion was 69%, the specificity 79%, and the accuracy 76%. The difference in diagnostic accuracy was statistically significant (McNemar's test, P=0.039). CONCLUSIONS: SPECT scanning using Ga and integrated low-dose CT is a very useful diagnostic imaging technique because it improves the diagnostic specificity of Ga SPECT to allow the highly specific diagnosis of cardiac sarcoidosis.

Serial assessment of left ventricular function in various patient groups with Tl-201 gated myocardial perfusion SPECT.

PURPOSE: The present study was performed to assess stress-related left ventricular (LV) function variations in various patient groups and to determine if they were affected by sex or the type of stress experienced. We used thallium (Tl)-201 gated myocardial perfusion single-photon emission computed tomography (SPECT) for the analysis. MATERIALS AND METHODS: A total of 270 patients were examined by electrocardiography-gated myocardial perfusion SPECT imaging to assess LV function. After injection of Tl-201 at a dose of 111 MBq at peak stress, SPECT scans were acquired at 10 min (after stress) and 3 h (rest) after injection on a three-headed camera. RESULTS: In the normal perfusion group, the mean LV ejection fraction (LVEF) was significantly higher, and both the end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) were significantly lower in women than in men (P < 0.05). Poststress stunning occurred in 29 of 98 patients (30.0%) in the ischemia group and in 42 of 90 patients (46.7%) in the fixed group. There was a significant difference in poststress stunning between bicycle ergometer stress and dipyridamole stress (P < 0.05). CONCLUSION: In patients with normal perfusion, LVEF, EDVI, and ESVI determined by gated Tl-201 SPECT should be corrected for sex. In addition, the influence of the type of stress should be considered when assessing stress-related LV function variations.

Usefulness of [123I]metaiodobenzylguanidine ([123I]MIBG) myocardial scintigraphy in differentiating between Alzheimer's disease and dementia with Lewy bodies.

OBJECTIVE: To confirm the clinical usefulness of [123I] metaiodobenzylguanidine ([123I]MIBG) myocardial scintigraphy in the antemortem differential diagnosis between patients with Alzheimer's disease (AD) and those with dementia with Lewy bodies (DLB). PATIENTS AND METHODS: We compared cardiac [123I] MIBG uptake in 10 patients with AD with that in 10 patients with DLB. We selected the patients with AD or DLB by using stringent diagnostic criteria that combined commonly used clinical criteria with tau protein levels in cerebrospinal fluid and radiographical examinations. RESULTS: The heart to mediastinum ratio of [123I]MIBG uptake in all the patients with DLB was significantly lower than that in the patients with AD (p<0.01). CONCLUSION: This study confirms that [123I]MIBG myocardial scintigraphy is useful in the antemortem differential diagnosis of AD and DLB.

Hilar and pancreatic gallium-67 accumulation is characteristic feature of autoimmune pancreatitis.

INTRODUCTION AND AIMS: Autoimmune pancreatitis is characterized by severe lymphocytic inflammation, suggesting that gallium-67 scintigraphy provides a useful tool for detecting characteristic lesions of this disease, because gallium-67 concentrates in lymphoid cells. We tried to determine whether gallium-67 accumulates in the characteristic lesions. METHODOLOGY: We performed gallium-67 scintigraphy in 24 patients with autoimmune pancreatitis before and after 4 weeks of corticosteroid therapy and determined the factors associated with positive images. RESULTS: Sixteen patients (67%) had marked gallium-67 accumulation in the pancreas before corticosteroid therapy and negative images after 4 weeks of therapy, and they had significantly higher serum IgG4 values than did those without gallium-67 accumulation (median, 758 mg/dL versus 329 mg/dL; p = 0.011). Marked hilar gallium-67 accumulation was found in 16 patients (67%) and was also associated with significantly higher serum IgG4 values than did those without it (median, 758 versus 239 mg/dL; p = 0.0044). Among 16 patients with positive hilar images, 12 had positive pancreatic uptake and 5 had both pancreatic and salivary gland uptakes. CONCLUSIONS: Hilar and pancreatic accumulation of gallium-67 is a characteristic feature of autoimmune pancreatitis during the active stage of the disease, when IgG4 serum levels are high.