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The role of torso computed tomography (CT) in evaluating body composition has been unexplored. This study assessed the potential of low-dose torso CT from positron emission tomography (PET)/CT for analyzing body composition and its relation to muscle strength. We retrospectively recruited 384 healthy Korean adults (231 men, 153 women) who underwent torso 18F-FDG PET/CT, bioelectrical impedance analysis (BIA), and muscle strength tests (handgrip strength [HGS] and knee extension strength [KES]). CT images were segmented into three compartments: torso volumetric, abdominal volumetric, and abdominal areal. Muscle amounts from each compartment were indexed to height (m2). BIA and HGS served as reference standards, with correlation coefficients (r) calculated. Torso muscle volumetric index (TorsoMVI) had the strongest correlations with BIA-derived values (r = 0.80 for men; r = 0.73 for women), surpassing those from the abdominal compartments. TorsoMVI was also correlated significantly with HGS (r = 0.39, p < 0.01) and differentiated between normal and possible sarcopenia in men (n = 225, 5960 ± 785 cm3/m2 vs. n = 6, 5210 ± 487 cm3/m2, p = 0.02). In women, KES correlated more strongly with muscle parameters than HGS. Despite gender-specific variations, torso CT-derived parameters show promise for evaluating body composition and sarcopenia. [ABSTRACT FROM AUTHOR]

18F-FP-CIT is a high-resolution imaging marker of nigrostriatal neuronal integrity, differentiating Parkinsonism with loss of dopaminergic terminals (presynaptic Parkinsonian syndrome [PS]) from Parkinsonism without nigrostriatal degeneration (non-PS). We assessed the diagnostic accuracy of 18F-FP-CIT PET in patients with clinically uncertain PS (CUPS) at the first visit. Among the 272 patients who underwent 18F-FP-CIT PET imaging at the first visit between September 2008 and July 2012, 111 had CUPS (age, 62.6 ± 10.5 y; male:female, 45:66; symptom duration, 13.1 ± 8.8 months). Uncertainty criteria included only one of the three cardinal signs of Parkinsonism, two signs without bradykinesia, or atypical signs. The baseline clinical and 18F-FP-CIT PET imaging diagnostic accuracy was compared with the accuracy of clinical diagnosis after > 2-year follow-up. Nuclear medicine physicians assessed the 18F-FP-CIT PET images visually. Focal dopamine transporter binding deficit in the posterior putamen was considered PS. Bilateral symmetric striatum without focal deficit, suggesting normal 18F-FP-CIT PET, and focal deficits elsewhere in the striatum suggesting vascular Parkinsonism were considered non-PS. Seventy-nine patients had PS, and 32 did not. Baseline clinical diagnosis included PS in 45 patients, non-PS in 24, and inconclusive in 42. Among patients in whom initial clinical diagnosis (PS or non-PS) was possible, the sensitivity, specificity, and accuracy of the baseline clinical and 18F-FP-CIT PET imaging diagnoses were 54.4, 50.0, and 53.2%, and 98.7, 100, and 99.1%, respectively. The respective positive and negative predictive values were 95.6 and 66.7%, and 100 and 97.0%. Among those with initially inconclusive diagnosis, 64.2% were eventually diagnosed with PS while 35.7% were diagnosed with non-PS. The final clinical diagnosis of these patients all matched those made by 18F-FP-CIT PET imaging, except in one patient with scan without evidence of dopaminergic deficit (SWEDD). 18F-FP-CIT PET diagnosis was more accurate than clinical diagnosis, reducing the false-negative and inconclusive clinical diagnosis rates at baseline in patients with CUPS. [ABSTRACT FROM AUTHOR]

Nuclear medicine neuroimaging is able to show functional and molecular biologic abnormalities in various neuropsychiatric diseases. Therefore, it has played important roles in the clinical diagnosis and in research on the normal and pathological states of the brain. More than 400 outstanding studies have been conducted by Korean researchers over the past 60 years. In the 1990s, when multiheaded single-photon emission computed tomography (SPECT) scanners were first introduced in South Korea, stroke research using brain perfusion SPECT was conducted. With the spread of positron emission tomography (PET) scanners in the 2000s, research on the clinical usefulness of PET and the evaluation of pathophysiology in various diseases such as epilepsy, brain tumors, degenerative brain diseases, and other neuropsychiatric diseases were actively conducted using [18F]FDG and various neuroreceptor tracers. In the 2010s, with the clinical application of new radiopharmaceuticals for amyloid and tau imaging, research demonstrating the clinical usefulness of PET imaging and the pathophysiology of dementia has increased rapidly. It is expected that the role of nuclear medicine will expand with the development of new radiopharmaceuticals and analysis technologies, along with the application of artificial intelligence for early and differential diagnosis, and the development of therapeutic agents for degenerative brain diseases. [ABSTRACT FROM AUTHOR]

Delayed phase 18F-FP-CIT PET (dCIT) can assess the striatal dopamine transporter binding to detect degenerative parkinsonism (DP). Early phase 18F-FP-CIT (eCIT) can assess the regional brain activity for differential diagnosis among parkinsonism similar with 18F-FDG PET. We evaluated the diagnostic performance of dual phase 18F-FP-CIT PET (dual CIT) and 18F-FDG PET compared with clinical diagnosis in 141 subjects [36 with idiopathic Parkinson's disease (IPD), 77 with multiple system atrophy (MSA), 18 with progressive supranuclear palsy (PSP), and 10 with non-DP)]. Visual assessment of eCIT, dCIT, dual CIT, 18F-FDG and 18F-FDG PET with dCIT was in agreement with the clinical diagnosis in 61.7%, 69.5%, 95.7%, 81.6%, and 97.2% of cases, respectively. ECIT showed about 90% concordance with non-DP and MSA, and 8.3% and 27.8% with IPD and PSP, respectively. DCIT showed ≥ 88% concordance with non-DP, IPD, and PSP, and 49.4% concordance with MSA. Dual CIT showed ≥ 90% concordance in all groups. 18F-FDG PET showed ≥ 90% concordance with non-DP, MSA, and PSP, but only 33.3% concordance with IPD. The combination of 18F-FDG and dCIT yielded ≥ 90% concordance in all groups. Dual CIT may represent a powerful alternative to the combination of 18F-FDG PET and dCIT for differential diagnosis of parkinsonian disorders. [ABSTRACT FROM AUTHOR]

Imaging biomarkers support the diagnosis of Alzheimer's disease (AD). We aimed to determine whether combining automated brain volumetry on MRI and quantitative measurement of tau deposition on [18F] THK-5351 PET can aid discrimination of AD spectrum. From a prospective database in an IRB-approved multicenter study (NCT02656498), 113 subjects (32 healthy control, 55 mild cognitive impairment, and 26 Alzheimer disease) with baseline structural MRI and [18F] THK-5351 PET were included. Cortical volumes were quantified from FDA-approved software for automated volumetric MRI analysis (NeuroQuant). Standardized uptake value ratio (SUVR) was calculated from tau PET images for 6 composite FreeSurfer-derived regions-of-interests approximating in vivo Braak stage (Braak ROIs). On volumetric MRI analysis, stepwise logistic regression analyses identified the cingulate isthmus and inferior parietal lobule as significant regions in discriminating AD from HC and MCI. The combined model incorporating automated volumes of selected brain regions on MRI (cingulate isthmus, inferior parietal lobule, hippocampus) and SUVRs of Braak ROIs on [18F] THK-5351 PET showed higher performance than SUVRs of Braak ROIs on [18F] THK-5351 PET in discriminating AD from HC (0.98 vs 0.88, P = 0.033) but not in discriminating AD from MCI (0.85 vs 0.79, P = 0.178). The combined model showed comparable performance to automated volumes of selected brain regions on MRI in discriminating AD from HC (0.98 vs 0.94, P = 0.094) and MCI (0.85 vs 0.78; P = 0.065). [ABSTRACT FROM AUTHOR]

Background: To date, the clinical significance of visually equivocal amyloid positron emission tomography (PET) has not been well established. Objective: We studied the clinical significance of equivocal amyloid PET images from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Methods: Subjects with F-18 florbetapir PET scans at baseline who were followed up for 4 years were selected. Clinical characteristics, imaging biomarkers, cognitive function, and rate of conversion to AD were compared in subjects with visually equivocal findings. Results: Of 249 subjects who completed the follow-up, 153 (61.4%), 20 (8.0%), and 129 (30.5%) were F-18 florbetapir-negative, -equivocal, and -positive, respectively. The mean standardized uptake value ratios (SUVR) of F-18 florbetapir PET were 0.75 ± 0.04, 0.85 ± 0.10, and 1.00 ± 0.09 for each group (p <0.001 between groups), and 15.0%, 70.0%, and 98.7% of patients were quantitatively above the positive threshold. The change in the SUVR of F-18 florbetapir PET was higher in the equivocal (6.09 ± 3.61%, p <0.001) and positive (3.13 ± 4.38%, p <0.001) groups than the negative group (0.88 ± 4.28%). Among the subjects with normal or subjective memory impairment and mild cognitive impairment, 5.3% with negative amyloid PET and 37.5% with positive amyloid PET converted to AD over the 4-year period. None of the equivocal amyloid PET subjects converted to AD during this period. Conclusion: Approximately 8% of subjects from the ADNI cohort showed visually equivocal amyloid PET scans with intermediate load and rapid accumulation of amyloid, but did not convert to AD during the 4-year follow-up. [ABSTRACT FROM AUTHOR]

Objective: 18F-labeled fluoropropyl-carbomethoxylodopropyl-nor-ß-tropane ([18F]FP-CIT) positron emission tomography (PET) is a useful tool for evaluating disease progression in Parkinson's disease (PD) patients. We evaluated the test–retest reproducibility of [18F]FP-CIT PET measures in essential tremor (ET) and PD patients. Methods: Fifteen ET (68.9 ± 6.6 years) and 10 PD patients (70.5 ± 6.3 years; Hoehn and Yahr stage, 2.3 ± 0.8) underwent two [18F]FP-CIT PET/CT scans with an interval of 48 ± 7 day. For both the test and retest studies, standardized uptake value ratios were estimated for 90-min and 3-h acquisitions for the caudate, anterior putamen, and posterior putamen using T1-MRI-based normalization (automatic) and fixed-VOI (manual) methods, with the occipital lobe as a reference. Reproducibility was evaluated by the bias, variability, percent test–retest, within-subject coefficient of variation, repeatability coefficient, and intraclass correlation coefficient (ICC). Results: Reproducibility was excellent, with low variability (ET: 6.99–8.02%, PD: 3.51–6.94%) and high reliability (ICC; ET: 0.88–0.96, PD: 0.98–0.99). The ET group showed higher variability and lower ICCs than the PD group. The variability in the 90-min images (ET: 7.85–8.59%, PD: 1.52–2.75%) was comparable to that in the 3-h images (ET: 6.99–8.02%, PD: 3.51–6.94%). There were no differences in variability among the subregions in the ET group. In the PD group, the variability was high in the posterior putamen (automatic method: 6.94%, manual method: 11.80%). The test–retest variability and ICCs were similar for the manual and automatic methods. Conclusion: [18F]FP-CIT PET is reproducible for the quantitative measurement of DAT binding in both ET and PD individuals, independent of the acquisition time or analysis method. Also, the automatic method is more suitable for evaluating early loss of DAT binding in patients with PD [ABSTRACT FROM AUTHOR]

We present the case of a patient with biliary and duodenal atresia who showed false-negative hepatobiliary scintigraphy results. The patient was born at 37 weeks and 2 days of gestation. Her mother had undergone amnioreduction after detection of a double-bubble ultrasound sign in the fetal abdomen. At 2 days of age, total serum bilirubin level was elevated. On hepatobiliary scintigraphy 4 days later, the gallbladder was visualized from 30 min and it showed duodeno-gastric reflux at 240 min. After 24 h, the radiotracer was almost washed out in the hepatic parenchyma, but there was retention in the gastroduodenal junction. Because the biliary to duodenal transit was visible, biliary atresia seemed unlikely. Abdominal ultrasonography at 7 days of age showed a small dysmorphic gallbladder, but triangular cord sign was not definite. Magnetic resonance cholangiography revealed atretic gallbladder. Although cystic and common bile ducts were visible, the proximal common hepatic bile duct was not visible. The next day, serum total bilirubin levels remained elevated (17.1 mg/dl) with direct bilirubin level of 1.2 mg/dl. Kasai portoenterostomy with duodeno-duodenostomy was performed at 10 days of age. Histopathological evaluation showed a fibrous obliteration of the common bile duct, consistent with that of biliary atresia. [ABSTRACT FROM AUTHOR]

Purpose: Dopamine transporter imaging is suggested to be a useful imaging biomarker for Parkinson's disease (PD) progression and monitoring drug effects. We investigated the longitudinal decline characteristics of striatal [F]FP-CIT uptake in PD. Methods: We retrospectively reviewed 35 PD patients and 9 non-PD patients. All patients underwent [F]FP-CIT PET at the initial diagnosis and follow-up. PET images were spatially normalized and analyzed with eight striatal and one occipital VOI templates. We measured the specific to non-specific binding ratio (SNBR) of the striatal subregions and calculated the absolute annual reduction (AAR) and relative annual reduction (%RAR) of the SNBRs. Results: Total striatal SNBRs in PD patients were significantly lower than those in non-PD patients, with the most significant difference in the posterior putamen. Both AAR (0.26 ± 0.14 vs. 0.09 ± 0.19, p < 0.05) and %RAR (6.9 ± 3.5 vs. 1.2 ± 2.7, p < 0.001) of total striatal SNBRs were significantly greater in PD than non-PD patients. There were no significant differences in the AAR and %RAR of total striatal SNBRs between elderly and young onset PD. The AARs of the posterior putamen were higher in early PD than in advanced PD. Conversely, the %RARs were not significantly different between early and more advanced PD. The disease duration was significantly negatively correlated with the AAR but not with the %RAR of the posterior putamen. Conclusions: The longitudinal decline of striatal [F]FP-CIT uptake in PD was nonlinear and significantly faster than that in non-PD, with a different rate of decline among the striatal subregions. [ABSTRACT FROM AUTHOR]

Purpose: Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN. Methods: We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months. Results: Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2-10 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively. Conclusions: According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients. [ABSTRACT FROM AUTHOR]

We report a case with altered biodistribution of Tc-dicarboxypropane diphosphonate (Tc-DPD) on whole body bone scan after intravenous iron supplement therapy. A 47-year-old male patient who had recently been detected with a hepatic mass suggestive of hepatocellular carcinoma underwent bone scan as staging work-up before surgery. Bone scan images at 3 h after injection of Tc-DPD demonstrated unusually increased blood pool activities in the heart, liver, and spleen with usual skeletal uptakes. The patient had been treated for severe anemia from hemorrhoid with two intravenous administration of ferric hydroxide carboxymaltose complex at approximately 22 h and 2 h prior to the Tc-DPD injection, which we consider as the most probable cause of altered biodistribution of Tc-DPD. [ABSTRACT FROM AUTHOR]

Purpose: F-FP-CIT [F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] is useful for detecting striatal dopamine transporter (DAT). Since FP-CIT shows relatively high affinities for DAT and serotonin transporter (SERT), its binding can be influenced by selective serotonin reuptake inhibitors (SSRIs). We aimed to evaluate the effect of SSRIs on the binding of F-FP-CIT. Methods: In our F-FP-CIT positron emission tomography (PET) data pool, images of 24 drug-naive Parkinson's disease (PD) patients (62.6 ± 10.6 years), 111 PD patients taking SSRIs [escitalopram ( n = 19) and fluvoxamine ( n = 20)] or clonazepam ( n = 72), and 10 normal people were reviewed. PET images acquired 3 h after F-FP-CIT injection were analyzed by an automated method using a predefined volume of interest (VOI) set of the striatum (ST), occipital cortex (OC), raphe nuclei (RN), and cerebellar cortex (CB). The uptake ratios (URs) of each VOI to the CB were compared among the groups. Results: The ST/CB URs of all PD groups were significantly lower than that of normal group. When adjusted for drug severity, ST/CB URs were higher in drug-naive group but had no difference among antidepressant groups. Whereas OC/CB URs were not different among groups ( p > 0.05), RN/CB URs were significantly lower in SSRI groups than in non-SSRI groups ( p < 0.001) and showed similar results when adjusted for disease severity. Conclusions: PD patients taking SSRIs showed significantly decreased URs in the RN but not the OC. When adjusted for Hoehn and Yar (HY) score, ST URs were not different among antidepressant groups. This result suggests that the OC may be used as a reference region for the quantification of DAT binding in F-FP-CIT PET images of PD patients taking SSRIs. [ABSTRACT FROM AUTHOR]

Purpose: Dopamine transporter (DAT) imaging can demonstrate presynaptic dopaminergic neuronal loss in Parkinson's disease (PD). However, differentiating atypical parkinsonism (APD) from PD is often difficult. We investigated the usefulness of dual-phase F-18 FP-CIT positron emission tomography (PET) imaging in the differential diagnosis of parkinsonism. Methods: Ninety-eight subjects [five normal, seven drug-induced parkinsonism (DIP), five essential tremor (ET), 24 PD, 20 multiple system atrophy-parkinson type (MSA-P), 13 multiple system atrophy-cerebellar type (MSA-C), 13 progressive supranuclear palsy (PSP), and 11 dementia with Lewy bodies (DLB)] underwent F-18 FP-CIT PET. PET images were acquired at 5 min (early phase) and 3 h (late phase) after F-18 FP-CIT administration (185 MBq). Regional uptake pattern of cerebral and cerebellar hemispheres was assessed on early phase images and striatal DAT binding pattern was assessed on late phase images, using visual, quantitative, and statistical parametric mapping (SPM) analyses. Results: Striatal DAT binding was normal in normal, ET, DIP, and MSA-C groups, but abnormal in PD, MSA-P, PSP, and DLB groups. No difference was found in regional uptake on early phase images among normal DAT binding groups, except in the MSA-C group. Abnormal DAT binding groups showed different regional uptake pattern on early phase images compared with PD in SPM analysis (FDR < 0.05). When discriminating APD from PD, visual interpretation of the early phase image showed high diagnostic sensitivity and specificity (75.4 % and 100 %, respectively). Regarding the ability to distinguish specific APD, sensitivities were 81 % for MSA-P, 77 % for MSA-C, 23 % for PSP, and 54.5 % for DLB. Conclusions: Dual-phase F-18 FP-CIT PET imaging is useful in demonstrating striatal DAT loss in neurodegenerative parkinsonism, and also in differentiating APD, particularly MSA, from PD. [ABSTRACT FROM AUTHOR]

A 53-year-old man with fever of unknown origin underwent F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) as a workup for a fever of unknown origin. On presentation, he complained of fever, chills, and myalgia. The F-18 FDG PET/CT scan showed diffusely increased uptake of the liver with mild hepatomegaly. A liver biopsy then revealed fibrin-ring granulomas typically seen in Q fever. The patient was later serologically diagnosed as having acute Q fever as the titers for C. burnetii IgM and IgG were 64:1 and 16:1, respectively. He recovered completely following administration of doxycycline. This indicates that F-18 FDG PET/CT may be helpful for identifying hepatic involvement in Q fever as a cause of fever of unknown origin. [ABSTRACT FROM AUTHOR]

Purpose: To compare F-18-fluoro-2-deoxy- D-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) imaging at two different circulation times after injection of F-18 FDG in order to measure atherosclerosis in carotid arteries. Methods: We assessed 12 patients with recent symptomatic plaques in the carotid arteries. F-18 FDG PET/CT carotid plaque imaging was performed for 20 min at 2 h after F-18 FDG injection in five patients and at 3 h in seven patients. We measured vessel wall uptake using the maximal standardized uptake value (SUV), and the mean and maximal blood target-to-background ratios (TBR) of the symptomatic carotid arteries. Blood pool activity (BPA) was measured as the mean SUV of the superior vena cava (SVC) and jugular vein of these 12 patients, and in 14 age- and gender-matched patients who underwent whole-body F-18 FDG PET/CT examinations 1 h after injection. Results: F-18 FDG PET/CT revealed visible F-18 FDG uptake in all patients with symptomatic carotid plaques. Maximal SUV did not differ between groups evaluated at 2 h and 3 h (2.62 ± 0.45 vs 3.00 ± 0.85, p = 0.335). However, mean (2.04 ± 0.22 vs 3.54 ± 0.62, p < 0.05) and maximal (1.65 ± 0.15 vs 2.70 ± 0.42, p < 0.05) TBR values that were normalized to BPA in the SVC differ significantly. Conclusions: Symptomatic carotid plaques are visualized for a relatively short period of imaging time on ≥1-h PET/CT images. Quantitative parameters of atherosclerotic carotid arteries are preserved or even increased over time, whereas those of blood pools are decreased. [ABSTRACT FROM AUTHOR]