Quantitative Susceptibility Mapping of the Hippocampal Fimbria in Alzheimer's Disease.

BACKGROUND: The fimbria is a small white matter bundle that connects the hippocampus to the rest of the brain. Damage to the hippocampal gray matter is established in Alzheimer's disease (AD), but the hippocampal fimbrial status in the pathogenesis of AD is unclear. AD-related demyelination and iron deposition alter the diamagnetic and paramagnetic composition of tissues, which can be measured by quantitative susceptibility mapping (QSM). HYPOTHESIS: AD is associated with microstructural changes in the fimbria that might be detected by QSM. STUDY TYPE: Retrospective cross-sectional study. SUBJECTS: In all, 53 adults comprised of controls (n = 30), subjects with early stage AD (n = 13), and late stage AD (n = 10) who were classified according to their amyloid and tau status and presence of hippocampal atrophy. FIELD STRENGTH / SEQUENCE: 3T; 3D fast-field echo sequence for QSM analysis and 3D T1 -weighted MP-RAGE sequence for anatomical analysis. ASSESSMENT: Segmentation of the left hippocampal fimbria subfield was performed on T1 -weighted images and was applied to the coregistered QSM map for extraction of the mean, median, minimum, and maximum values of QSM. STATISTICAL TESTS: Group comparison of QSM values using analysis of variance (ANOVA) with post-hoc Tukey's test, accuracy of binary differentiation using receiver operating characteristic (ROC), and individual classification using discriminant analysis. RESULTS: QSMmean and QSMmedian values were significantly different among the three groups (P < 0.05) and showed a shifting from negative in the control group to positive in the AD group. The control and early AD subjects, who have normal hippocampal volumes, were differentiated by the QSMmean value (area under the curve [AUC] 0.744, P < 0.05) and the QSMmedian value (AUC 0.782, P < 0.05). Up to 76% of subjects (inclusive of 26 controls and six with early AD) were correctly classified using a model incorporating clinical and radiologic data. DATA CONCLUSION: The fimbria showed higher magnetic susceptibility in AD compared with controls. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 3.

Radioembolization with 90Y glass microspheres for hepatocellular carcinoma: significance of pretreatment 11C-acetate and 18F-FDG PET/CT and posttreatment 90Y PET/CT in individualized dose prescription.

PURPOSE: The aim of this study was to establish an algorithm for the prescription of 90Y glass microsphere radioembolization (90Y-GMRE) of HCC in individual patients based on the relationship between tumour dose (TD) and response validated by 90Y PET/CT dosimetry and dual-tracer PET/CT metabolic parameters. METHODS: The study group comprised 62 HCC patients prospectively recruited for 90Y-GMRE who underwent pretreatment dual-tracer (11C-acetate and 18F-FDG) PET/CT as surrogate markers of HCC cellular differentiation. Pretreatment tumour-to-nontumour ratio on 99mTc-MAA SPECT/CT (T/NTMAA) was correlated with posttreatment 90Y PET/CT T/NT90Y after quantification validation. The TD-response relationship for HCC of different tracer groups was assessed on follow-up PET/CT 2 months after treatment. RESULTS: 90Y PET/CT was accurate in the measurement of recovery of injected 90Y activity (81.9-99.9%, median 94.8%). Pretreatment SPECT/CT T/NTMAA was strongly correlated with posttreatment 90Y PET/CT T/NT90Y (5.6 ± 3.2 versus 5.9 ± 3.5, T/NT90Y 1.01 × T/NTMAA + 0.161, r = 0.918, P < 0.05). The response rates were 72.4% (21/29), 70.6% (12/17) and 25% (4/16) for well, moderately and poorly differentiated HCC, respectively. The cut-off TD for a good response was significantly different between poorly differentiated and well/moderately differentiated HCC (262 Gy versus 152/174 Gy) with 89.2% sensitivity and 88% specificity. At a limiting tolerated liver dose of 70 Gy, the T/NTMAA thresholds for predicting a good response in poorly differentiated and well/moderately differentiated HCC were 3.5 and 2.0/2.3. Disregarding HCC cellular differentiation, the cut-off TD became 170 Gy, with lower sensitivity (70.3%) and specificity (76%). CONCLUSION: 90Y PET/CT can provide accurate dosimetry for 90Y-GMRE. Pretreatment T/NTMAA predicts posttreatment T/NT90Y. The TD thresholds for a good response are tracer-dependent, with a strong correlation between HCC radiosensitivity and cellular differentiation and other PET-based parameters. These cytokinetic factors improve treatment efficacy while minimizing organ damage for the prescription of personalized 90Y-GMRE.

(11)C-acetate as a new biomarker for PET/CT in patients with multiple myeloma: initial staging and postinduction response assessment.

PURPOSE: We investigated the potential value of (11)C-acetate (ACT) PET/CT in characterizing multiple myeloma (MM) compared with (18)F-FDG PET/CT. Bone marrow histological and whole-body (WB) MRI findings served as the reference standards. METHODS: In this prospective study, 15 untreated MM patients (10 men and 5 women, age range 48-69 years) underwent dual-tracer (11)C-ACT and (18)F-FDG PET/CT and WB MRI for pretreatment staging, and 13 of them had repeated examinations after induction therapy. Diffuse and focal bone marrow uptake was assessed by visual and quantitative analyses, including measurement of the maximum standardized uptake value (SUVmax). Between-group differences and correlations were assessed with the Mann-Whitney U test and the Pearson test. RESULTS: At staging, all 15 patients had diffuse myeloma involvement upon bone marrow examination with 30-90 % of plasma cell infiltrates. Diffuse infiltration was detected in all of them (100 %) using (11)C-ACT with a positive correlation between bone marrow uptake values and percentages of plasma cell infiltrates (r = +0.63, p=0.01). In contrast, a diagnosis of diffuse infiltration could be established using (18)F-FDG in only six patients (40 %). Focal lesions were shown in 13 patients on both (11)C-ACT PET/CT and WB MRI, and in 10 patients on (18)F-FDG PET/CT. Focal lesions demonstrated (11)C-ACT uptake with a mean SUVmax of 11.4 ± 3.3 (range 4.6-19.6, n=59), which was significantly higher than the (18)F-FDG uptake (mean SUVmax 6.6 ± 3.1, range 2.3-13.7, n=29; p<0.0001). After treatment, the diffuse bone marrow (11)C-ACT uptake showed a mean SUVmax reduction of 66 % in patients with at least a very good partial response versus 34 % in those with at most a partial response only (p=0.01). CONCLUSION: PET/CT using (11)C-ACT as a biomarker showed a higher detection rate for both diffuse and focal myeloma lesions at diagnosis than using (18)F-FDG, and may be valuable for response assessment.

The Complementary Role of PET to Pathology in Differentiating the Primary Origin of a Malignant Skin Nodule from Liver or Lung.

Metastasis from unknown primary is always a challenge because finding the true primary tumor significantly affects subsequent management. We present a case of malignant abdominal wall nodule initially diagnosed as metastasis from hepatocellular carcinoma through excisional biopsy and immunohistochemical (IHC) staining. Dual-tracer positron emission tomography/computed tomography (PET/CT) with 11C-acetate and 18F-FDG, however, showed metabolic findings in favor of metastasis from lung origin, which was finally confirmed by ensuing a lung biopsy with additional IHC stains. This case illustrates the complementary molecular role of PET to pathology, particularly when dual-tracer or multi-tracer PET is used in conjunction with pathology methods for cross referencing and confirmation.

Diagnosis of Seronegative Rheumatoid Arthritis by 68 Ga-FAPI PET/CT.

Early diagnosis of rheumatoid arthritis with the initiation of disease-modifying antirheumatic drugs is important to prevent future disability. Seronegative rheumatoid arthritis lacks the classical immunological markers, thus imposing clinical diagnostic difficulty. In this case, we reported 68 Ga-FAPI PET/CT findings of seronegative rheumatoid arthritis in a 60-year-old lady. This case illustrates how 68 Ga-FAPI PET/CT aids in the diagnosis of seronegative rheumatoid arthritis.

Clinical and neuroimaging markers of neurodegeneration in first-degree relatives of patients with REM sleep behavior disorder with and without isolated rapid eye movement sleep without atonia: A case-control clinical and dopamine PET study.

OBJECTIVES: The current study aimed to examine the neurodegenerative implication of isolated REM sleep without atonia (RSWA) among first-degree relatives of patients with REM sleep behaviour disorder (RBD). METHODS: This cross-sectional case-control study recruited three groups of subjects: First-degree relatives of RBD patients with isolated RSWA (n = 17), first-degree relatives of RBD patients without isolated RSWA (n = 18), and normal controls who did not have any RWSA and family history of RBD (n = 15). Prodromal Parkinson's Disease likelihood ratio by the updated MDS Research Criteria and striatal dopaminergic transmission function of the subjects as assessed by triple-tracer (18F-DOPA, 11C-Raclopride, and 18F-FDG) PET/CT scan were used as proxy markers of neurodegeneration. RESULTS: In contrary to our hypothesis, the three groups did not differ in their pre- or post-striatal dopaminergic transmission function, and their Prodromal Parkinson's Disease likelihood ratio. However, they differed significantly in their frequency of a having first-degree relatives with Parkinson's disease or dementia of Lewy body (first-degree relativess with RSWA vs first degree relatives without RSWA vs normal controls = 58.8% vs 22.2% vs 0%, p = 0.001). CONCLUSION: FDRs of RBD patients with isolated RSWA did not have increased neurodegenerative markers compared to FDRs of RBD patients without isolated RSWA and normal control, despite an paradoxical increase in frequency of Parkinson's disease or dementia of Lewy body among their family compared to FDRs of RBD patients without isolated RSWA. Further longitudinal follow-up study will be needed to ascertain their long-term prognosis.

[18F]fluoroacetate positron emission tomography for hepatocellular carcinoma and metastases: an alternative tracer for [11C]acetate?

[11C]Acetate (ACT) positron emission tomography/computed tomography (PET/CT) is useful in the detection of hepatocellular carcinoma (HCC). This study aimed to evaluate whether [18F]fluoroacetate (FAC) could be an alternative analogue of [11C]ACT for the diagnosis of HCC. [18F]FAC was synthesized using the precursor t-butyl 2-(methanesulfonyloxy)ethanoate. Five volunteer patients with known HCC were recruited after consent. Whole-body [18F]FAC PET/CT was performed at 20 minutes and 1 hour postinjection and compared to [11C]ACT PET/CT at 20 minutes postinjection to assess biodistribution and tumor uptake characteristics. Qualitative and semiquantitative analyses were performed with statistical correlations on the physiologic organs of accumulation and HCC lesions for both tracers. [18F]FAC was obtained with 99% radiochemical purity, and the reaction yield was 16.0% with 1-hour synthesis time. The biodistribution of [18F]FAC on PET/CT was significantly different from that of [11C]ACT (p < .05) by the lack of preferential uptake in any specific organ, particularly the pancreas, resembling the pattern of blood-pool retention although partly metabolized via the bowel. There was no significant defluorination, and none of the [11C]ACT-avid HCC lesions showed increased [18F]FAC activity. These were different from the results reported on other species. [18F]FAC may not be a potential alternative tracer for [11C]ACT in PET/CT evaluation of HCC in human subjects.

Predictors for cognitive decline in patients with confluent white matter hyperintensities.

BACKGROUND: Although patients harboring confluent white matter hyperintensities (WMH) are at high risk of cognitive decline, this risk varies among individuals. We investigated the predictors for cognitive decline in stroke patients with confluent WMH. METHODS: We followed up 100 stroke patients with confluent WMH who were participants of the VITAmins TO Prevent Stroke study for 2 years. We investigated the association between clinical features, apolipoprotein E status, imaging measures (infarcts, microbleeds, volumes of WMH, cortical gray matter [cGM], lateral ventricles, and hippocampi), and B vitamins with changes in cognitive measures (clinical dementia rating scale, Mini-Mental State Examination, Mattis dementia rating scale--initiation/perseveration subscale). We performed Pittsburgh compound B imaging among dementia converters. RESULTS: Multivariate regression analysis showed that increase in clinical dementia rating scale grade was associated with cGM atrophy, absence of hyperlipidemia, and lower diastolic blood pressure at baseline. cGM atrophy and absence of hyperlipidemia were also associated with deterioration in Mini-Mental State Examination and Mattis dementia rating scale--initiation/perseveration subscale scores. Pittsburgh compound B retention typical of Alzheimer's disease was found only in 10% of dementia converters. Incident stroke and B vitamins were not associated with cognitive decline. CONCLUSIONS: Among stroke patients with confluent WMH, cGM atrophy and absence of hyperlipidemia are important predictors for cognitive decline. Significant cognitive decline can occur in the absence of incident stroke or Alzheimer's pathology.

Reliability of gradient-based segmentation for measuring metabolic parameters influenced by uptake time on 18F-PSMA-1007 PET/CT for prostate cancer.

Purpose: To determine an optimal setting for functional contouring and quantification of prostate cancer lesions with minimal variation by evaluating metabolic parameters on 18F-PSMA-1007 PET/CT measured by threshold-based and gradient-based methods under the influence of varying uptake time. Methods and materials: Dual time point PET/CT was chosen to mimic varying uptake time in clinical setting. Positive lesions of patients who presented with newly diagnosed disease or biochemical recurrence after total prostatectomy were reviewed retrospectively. Gradient-based and threshold-based tools at 40%, 50% and 60% of lesion SUVmax (MIM 6.9) were used to create contours on PET. Contouring was considered completed if the target lesion, with its hottest voxel, was delineated from background tissues and nearby lesions under criteria specific to their operations. The changes in functional tumour volume (FTV) and metabolic tumour burden (MTB, defined as the product of SUVmean and FTV) were analysed. Lesion uptake patterns (increase/decrease/stable) were determined by the percentage change in tumour SUVmax at ±10% limit. Results: A total of 275 lesions (135 intra-prostatic lesions, 65 lymph nodes, 45 bone lesions and 30 soft tissue lesions in pelvic region) in 68 patients were included. Mean uptake time of early and delayed imaging were 94 and 144 minutes respectively. Threshold-based method using 40% to 60% delineated only 85 (31%), 110 (40%) and 137 (50%) of lesions which all were contoured by gradient-based method. Although the overall percentage change using threshold at 50% was the smallest among other threshold levels in FTV measurement, it was still larger than gradient-based method (median: 50%=-7.6% vs gradient=0%). The overall percentage increase in MTB of gradient-based method (median: 6.3%) was compatible with the increase in tumour SUVmax. Only a small proportion of intra-prostatic lesions (<2%), LN (<4%), bone lesions (0%) and soft tissue lesions (<4%) demonstrated decrease uptake patterns. Conclusions: With a high completion rate, gradient-based method is reliable for prostate cancer lesion contouring on 18F-PSMA-1007 PET/CT. Under the influence of varying uptake time, it has smaller variation than threshold-based method for measuring volumetric parameters. Therefore, gradient-based method is recommended for tumour delineation and quantification on 18F-PSMA-1007 PET/CT.

Lower Posterior Cingulate N-Acetylaspartate to Creatine Level in Early Detection of Biologically Defined Alzheimer's Disease.

Alzheimer's disease (AD) was recently defined as a biological construct to reflect neuropathologic status, and both abnormal amyloid and tau are required for a diagnosis of AD. We aimed to determine the proton MR spectroscopic (1H-MRS) patterns of the posterior cingulate in biologically defined AD. A total of 68 participants were included in this study, comprising 37 controls, 16 early AD, and 15 late AD, who were classified according to their amyloid and tau status and presence of hippocampal atrophy. Compared with controls, early AD showed lower N-acetylaspartate (NAA)/creatine (Cr) (p = 0.003), whereas late AD showed lower NAA/Cr and higher myoInositol (mI)/Cr (all with p < 0.05). Lower NAA/Cr correlated with a greater global amyloid load (r = −0.47, p < 0.001) and tau load (r = −0.51, p < 0.001) and allowed a discrimination of early AD from controls (p < 0.001). Subgroup analysis showed that NAA/Cr also allowed a differentiation of early AD from controls in the cognitively unimpaired subjects, with an area under the receiver operating characteristics curve, sensitivity, and specificity of 0.96, 100%, and 83.8%, respectively. Lower posterior cingulate NAA levels may help to inform underlying neuropathologic changes in the early stage of AD.

PET/CT characteristics of isolated bone metastases in hepatocellular carcinoma.

PURPOSE: To compare the prognostic implications and positron emission tomography (PET)/computed tomography (CT) characteristics of isolated bone metastasis secondary to hepatocellular carcinoma (HCC) with those of HCC metastases to bone and other sites. MATERIALS AND METHODS: This study was approved by the institutional ethics committee, and informed consent was obtained from all patients. Extrahepatic metastases were diagnosed in 257 patients with HCC by using dual-tracer (carbon 11 [(11)C] acetate and fluorine 18 fluorodeoxyglucose [FDG]) PET/CT. Metastatic bone lesions were identified with visual inspection and semiquantitative assessment and confirmed with histopathologic examination and/or supported by findings at other radiologic examinations or serial PET/CT. RESULTS: The frequency of bone metastasis from HCC was 19% (49 of 257 patients; eight patients had histopathologic proof and 41 had imaging proof). Metastasis isolated to bone (group 1, 30 of 257 patients [12%]) was more common than metastasis to bone and other sites (group 2, 19 of 257 patients [7%]). At lesion-based analysis of group 1 (71 index lesions; mean lesion size ± standard deviation, 3.25 cm ± 1.88), (11)C acetate PET was more sensitive than FDG PET (93% [66 of 71 lesions] vs 62% [44 of 71 lesions], respectively; P < .05). The combined sensitivity was 97% (69 of 71 lesions) with dual-tracer PET and 72% (51 of 71 lesions) with CT. At patient-based analysis, (11)C acetate PET had an incremental value of 23% (seven of 30 patients) over FDG PET. At lesion-based analysis of group 2, FDG PET was more sensitive than (11)C acetate PET (87% [33 of 38 lesions] vs 50% [19 of 38 lesions], respectively; P < .05). Tracer avidities of metastatic bone lesions were closely correlated with that of their corresponding primary HCC tumors. The median survival time was longer in group 1 than in group 2 (18 months vs 11 months, respectively; P < .05). CONCLUSION: Isolated bone metastasis from HCC may not be as uncommon as previously believed. The detection of these metastases can be significantly enhanced with (11)C acetate PET compared with FDG PET alone. Identification of this group of patients also seems to have prognostic importance.

Can positron emission tomography with the dual tracers [11 C]acetate and [18 F]fludeoxyglucose predict microvascular invasion in hepatocellular carcinoma?

Microvascular invasion is a poor prognostic indicator of the recurrence of hepatocellular carcinoma (HCC) after surgical treatment. Positron emission tomography (PET) with [(18) F]fludeoxyglucose ([(18) F]FDG) as a tracer has been employed to predict the prognosis before surgery for various kinds of tumors, but it has not been found to be sensitive enough for HCC. Thus, [(11) C]acetate has been adopted as an additional tracer. This study was designed to evaluate the ability of dual-tracer PET ([(18) F]FDG and [(11) C]acetate) to predict microvascular invasion before liver resection or transplantation. Fifty-eight HCC patients who were preoperatively examined with whole-body dual-tracer PET were studied. Twenty-five patients were [(18) F]FDG-positive, and 56 were [(11) C]acetate-positive. The sensitivity of [(18) F]FDG in detecting primary HCC was 43%, and the sensitivity of [(11) C]acetate was 93%. Twenty-nine patients had HCC with microvascular invasion according to the final pathological examination. The sensitivity, specificity, positive predictive value, and negative predictive value of [(18) F]FDG PET in predicting microvascular invasion were 55.2%, 69%, 64%, and 60.6%, respectively; the corresponding rates for [(11) C]acetate PET were 93.1%, 0%, 48.2%, and 0%. The factors associated with HCC recurrence, which included multifocal involvement, a large tumor size, microsatellite lesions, poor HCC differentiation, and an advanced stage of disease, were analyzed and compared with positive PET results. A tumor size greater than 5 cm was significantly associated with positive [(18) F]FDG PET results; [(11) C]acetate was not associated with poor prognostic indicators. Preoperative [(18) F]FDG PET may predict microvascular invasion. The addition of [(11) C]acetate improves the overall sensitivity of PET, but it has no incremental value in predicting microvascular invasion.

Cortical and frontal atrophy are associated with cognitive impairment in age-related confluent white-matter lesion.

OBJECTIVE: Although age-related confluent white-matter lesion (WML) is an important substrate for cognitive impairment, the mechanisms whereby WML induces cognitive impairment are uncertain. The authors investigated cognitive predictors in patients with confluent WML. METHODS: Among 100 patients with ischaemic stroke with confluent WML on MRI, the authors assessed executive function and global cognition by the Mattis Dementia Rating Scale--Initiation/Perseveration Subscale (MDRS I/P) and Mini-Mental State Examination (MMSE), respectively. All volumetric measures were corrected for intracranial volume. The authors investigated the association between basic demography, vascular risk factors, APOE status, WML volume, infarct measures (volume, number, location), microbleed number, atrophy measures (global, central, regional) and cognitive performance. The authors also performed Pittsburgh Compound B (PIB) imaging among seven cognitive impaired patients with stroke. RESULTS: WML was no longer related to cognitive performance after adding atrophy into regression equations. Multivariate regression models showed that cortical grey matter volume independently accounted for performance on both the MDRS I/P (ß=0.241, p=0.045) and MMSE (ß=0.243, p=0.032). Models examining frontal subregions revealed that volumes of both left (ß=0.424, p<0.001) and right (ß=0.219, p=0.045) lateral frontal orbital gyri predicted MDRS I/P, whereas education (ß=0.385, p<0.001) and left lateral frontal orbital gyrus (ß=0.222, p=0.037) predicted MMSE. Volumes of WML and cognitively relevant brain regions were significantly associated. Seven patients with PIB imaging showed no uptake pattern typical of Alzheimer's disease, suggesting a predominantly vascular aetiology for the cognitive impairment and brain changes in these patients. CONCLUSIONS: Cognitive impairment in patients with confluent WML is mediated by global and frontal cortical atrophy.

MRI-based Alzheimer's disease-resemblance atrophy index in the detection of preclinical and prodromal Alzheimer's disease.

Alzheimer's Disease-resemblance atrophy index (AD-RAI) is an MRI-based machine learning derived biomarker that was developed to reflect the characteristic brain atrophy associated with AD. Recent study showed that AD-RAI (≥0.5) had the best performance in predicting conversion from mild cognitive impairment (MCI) to dementia and from cognitively unimpaired (CU) to MCI. We aimed to validate the performance of AD-RAI in detecting preclinical and prodromal AD. We recruited 128 subjects (MCI=50, CU=78) from two cohorts: CU-SEEDS and ADNI. Amyloid (A+) and tau (T+) status were confirmed by PET (11C-PIB, 18F-T807) or CSF analysis. We investigated the performance of AD-RAI in detecting preclinical and prodromal AD (i.e. A+T+) among MCI and CU subjects and compared its performance with that of hippocampal measures. AD-RAI achieved the best metrics among all subjects (sensitivity 0.74, specificity 0.91, accuracy 85.94%) and among MCI subjects (sensitivity 0.92, specificity 0.81, accuracy 86.00%) in detecting A+T+ subjects over other measures. Among CU subjects, AD-RAI yielded the best specificity (0.95) and accuracy (85.90%) over other measures, while hippocampal volume achieved a higher sensitivity (0.73) than AD-RAI (0.47) in detecting preclinical AD. These results showed the potential of AD-RAI in the detection of early AD, in particular at the prodromal stage.

Current status of PSMA PET imaging in prostate cancer.

The past decade has witnessed the rising popularity and acceptance of molecular definitions on disease management. Prostate-specific membrane antigen (PSMA), in light of its molecular nature and cytokinetic properties, has rapidly become the target for development of a variety of functional tracers for PET/CT evaluation of prostate cancer. The most commonly used PSMA-binding analog is 68 Ga-labeled PSMA-11, which is now widely applied in both research and clinical settings. Literature data in the recent years have been enriched by a number of meta-analyses and systemic reviews on the evolving role of PSMA PET in primary diagnosis, staging, detection of biochemical recurrence after primary cancer treatment, identification, and significance of oligometastasis, as well as in restaging and treatment monitoring. Being a highly sensitive and reasonably specific molecular tracer, PSMA-binding analogs have a high potential to possess the majority of imaging characteristics required for a variety of management decisions in prostate malignancy.

The role of dopamine dysregulation and evidence for the transdiagnostic nature of elevated dopamine synthesis in psychosis: a positron emission tomography (PET) study comparing schizophrenia, delusional disorder, and other psychotic disorders.

There have been few studies performed to examine the pathophysiological differences between different types of psychosis, such as between delusional disorder (DD) and schizophrenia (SZ). Notably, despite the different clinical characteristics of DD and schizophrenia (SZ), antipsychotics are deemed equally effective pharmaceutical treatments for both conditions. In this context, dopamine dysregulation may be transdiagnostic of the pathophysiology of psychotic disorders such as DD and SZ. In this study, an examination is made of the dopamine synthesis capacity (DSC) of patients with SZ, DD, other psychotic disorders, and the DSC of healthy subjects. Fifty-four subjects were recruited to the study, comprising 35 subjects with first-episode psychosis (11 DD, 12 SZ, 12 other psychotic disorders) and 19 healthy controls. All received an 18F-DOPA positron emission tomography (PET)/magnetic resonance (MR) scan to measure DSC (Kocc;30-60 value) within 1 month of starting antipsychotic treatment. Clinical assessments were also made, which included Positive and Negative Syndrome Scale (PANSS) measurements. The mean Kocc;30-60 was significantly greater in the caudate region of subjects in the DD group (ES = 0.83, corrected p = 0.048), the SZ group (ES = 1.40, corrected p = 0.003) and the other psychotic disorder group (ES = 1.34, corrected p = 0.0045), compared to that of the control group. These data indicate that DD, SZ, and other psychotic disorders have similar dysregulated mechanisms of dopamine synthesis, which supports the utility of abnormal dopamine synthesis in transdiagnoses of these psychotic conditions.

Significant Value of 11C-Acetate and 18F-Fluorodeoxyglucose PET/Computed Tomography on 90Y Microsphere Radioembolization for Hepatocellular Carcinoma.

Pretreatment dual-tracer (18F-fluorodeoxyglucose and 11C-acetate) PET/computed tomography (CT) has potential to predict treatment response for 90Y microsphere radioembolization (RE) in patients with inoperable hepatocellular carcinoma (HCC). Patients with 11C-acetate-avid HCC have a better response to 90Y microsphere RE, and possibly better survival. Pretreatment dual-tracer PET/CT has a significant theranostic value on 90Y microsphere RE in determining target tumor dose for HCCs with different cellular differentiation, metabolic tumor volume, and functioning liver volume, and can be used to prescribe individual injected activity of 90Y microspheres.

Dual-Tracer PET/CT Differentiates 2 Types of Primary Cancers and Metastases in a Patient With Crossed Fused Renal Ectopia.

A patient was found incidentally on dual-tracer (C-acetate [ACT] and F-FDG [FDG]) PET/CT for having crossed fused renal ectopia and 2 types of malignant tumors, colonic carcinoma and renal cell carcinoma (RCC), each having its own characteristic tracer avidity. Multiple liver metastases were also mutually exclusive, with a purely ACT-avid group of metastatic lesions from RCC and another FDG-avid group from colonic carcinoma. Bone and lung metastases, however, could not be readily distinguishable in terms of primary origins. Crossed fused renal ectopia is a rare anomaly, even rarer to have RCC coexisting with a second primary malignancy.

Nosocomial transmission of hepatitis C virus in a liver transplant center in Hong Kong: implication of reusable blood collection tube holder as the vehicle for transmission.

BACKGROUND: A liver transplant recipient developed hospital-acquired symptomatic hepatitis C virus (HCV) genotype 6a infection 14 months post transplant. OBJECTIVE: Standard outbreak investigation. METHODS: Patient chart review, interviews of patients and staff, observational study of patient care practices, environmental surveillance, blood collection simulation experiments, and phylogenetic study of HCV strains using partial envelope gene sequences (E1-E2) of HCV genotype 6a strains from the suspected source patient, the environment, and the index patient were performed. RESULTS: Investigations and data review revealed no further cases of HCV genotype 6a infection in the transplant unit. However, a suspected source with a high HCV load was identified. HCV genotype 6a was found in a contaminated reusable blood-collection tube holder with barely visible blood and was identified as the only shared item posing risk of transmission to the index case patient. Also, 14 episodes of sequential blood collection from the source patient and the index case patient were noted on the computerized time log of the laboratory barcoding system during their 13 days of cohospitalization in the liver transplant ward. Disinfection of the tube holders was not performed after use between patients. Blood collection simulation experiments showed that HCV and technetium isotope contaminating the tip of the sleeve capping the sleeved-needle can reflux back from the vacuum-specimen tube side to the patient side. CONCLUSIONS: A reusable blood-collection tube holder without disinfection between patients can cause a nosocomial HCV infection. Single-use disposable tube holders should be used according to the recommendations by Occupational Safety and Health Administration and World Health Organization.

Comparative evaluation of long-term clinical efficacy with catheter-based percutaneous intramyocardial autologous bone marrow cell implantation versus laser myocardial revascularization in patients with severe coronary artery disease.

BACKGROUND: Catheter-based percutaneous laser myocardial revascularization (PMR) and intramyocardial direct bone marrow (BM) cell implantation have been investigated to treat patients with severe coronary artery disease (CAD). In both therapeutic approaches, direct local myocardial injury might be a common mechanism to induce therapeutic angiogenesis. METHODS: We studied the long-term clinical outcome in 16 patients with severe CAD who received either catheter-based PMR (n = 8) or intramyocardial autologous BM cell implantation (n = 8) as guided by electromechanical mapping. RESULTS: There were no significant differences in the baseline characteristics and the number of injection versus the number of laser pulse delivered between the 2 groups (P > .05). As compared with baseline, the New York Heart Association functional class and the number of anginal episodes were significantly reduced at 3- and 6-month follow-up in both BM and PMR groups (P < .05). However, the improvement in the New York Heart Association class and the reduction in anginal episodes at 18 months were only persisted in the BM group (P < .05) but not in the PMR group (P > .05). Furthermore, there were significant improvements in exercise time at 6- and 18-month follow-up, and the extent of stress-induced perfusion single-photon emission computed tomography defects at 6-month follow-up in BM group, as compared with baseline (all P < .05), but not in the PMR group (all P > .05). As compared with baseline, there were no significant changes in the total quality of life scores during follow-up in both groups (all P > .05). CONCLUSIONS: The results of this study demonstrated that the catheter-based intramyocardial autologous BM cell implantation might be more effective than PMR in improving symptoms and exercise capacity in patients with severe CAD. The beneficial effect of direct intramyocardial injection was over and beyond those noted in patients treated with PMR, suggesting a potential direct therapeutic effect of BM cells, rather than local myocardial injury alone on chronic ischemic myocardium.