Dementia imaging in clinical practice: a European-wide survey of 193 centres and conclusions by the ESNR working group.

PURPOSE: Through a European-wide survey, we assessed the current clinical practice of imaging in the primary evaluation of dementia, with respect to standardised imaging, evaluation and reporting. METHODS: An online questionnaire was emailed to all European Society of Neuroradiology (ESNR) members (n = 1662) and non-members who had expressed their interest in ESNR activities in the past (n = 6400). The questionnaire featured 42 individual items, divided into multiple choice, single best choice and free text answers. Information was gathered on the context of the practices, available and preferred imaging modalities, applied imaging protocols and standards for interpretation, reporting and communication. RESULTS: A total of 193 unique (non-duplicate) entries from the European academic and non-academic institutions were received from a total of 28 countries. Of these, 75% were neuroradiologists, 12% general radiologists and 11% (neuro) radiologists in training. Of responding centres, 38% performed more than five scans/week for suspected dementia. MRI was primarily used in 72% of centres. Over 90% of centres acquired a combination of T2w, FLAIR, T1w, DWI and T2*w sequences. Visual rating scales were used in 75% of centres, most often the Fazekas and medial temporal atrophy scale; 32% of respondents lacked full confidence in their use. Only 23% of centres performed volumetric analysis. A minority of centres (28%) used structured reports. CONCLUSIONS: Current practice in dementia imaging is fairly homogeneous across Europe, in terms of image acquisition and image interpretation. Hurdles identified include training on the use of visual rating scales, implementation of volumetric assessment and structured reporting.

Prospective trial to evaluate the prognostic value of different nutritional assessment scores in pancreatic surgery (NURIMAS Pancreas).

BACKGROUND: Preoperative nutritional status has an impact on patients' clinical outcome. For pancreatic surgery, however, it is unclear which nutritional assessment scores adequately assess malnutrition associated with postoperative outcome. METHODS: Patients scheduled for elective pancreatic surgery at the University of Heidelberg were screened for eligibility. Twelve nutritional assessment scores were calculated before operation, and patients were categorized as either at risk or not at risk for malnutrition by each score. The postoperative course was monitored prospectively by assessors blinded to the nutritional status. The primary endpoint was major complications evaluated for each score in a multivariable analysis corrected for known risk factors in pancreatic surgery. RESULTS: Overall, 279 patients were analysed. A major complication occurred in 61 patients (21·9 per cent). The proportion of malnourished patients differed greatly among the scores, from 1·1 per cent (Nutritional Risk Index) to 79·6 per cent (Nutritional Risk Classification). In the multivariable analysis, only raised amylase level in drainage fluid on postoperative day 1 (odds ratio (OR) 4·91, 95 per cent c.i. 1·10 to 21·84; P = 0·037) and age (OR 1·05, 1·02 to 1·09; P = 0·005) were significantly associated with major complications; none of the scores was associated with, or predicted, postoperative complications. CONCLUSION: None of the nutritional assessment scores defined malnutrition relevant to complications after pancreatic surgery and these scores may thus be abandoned.

How many outbreaks of nosocomial infections occur in German neonatal intensive care units annually?

BACKGROUND: Outbreaks on neonatal intensive care units (NICUs) achieve huge media interest, but the real number of neonatal outbreaks within a country is unknown. METHOD: This calculation is based on the data of the component for nosocomial infections in very low birth weight (VLBW) infants of the German national nosocomial infection surveillance system (NEO-KISS) from 2006 to 2011. Almost all German NICUs caring for VLBW infants participated in this surveillance system. A cluster was defined and an outbreak was assumed when at least two cases of severe neonatal infection (bloodstream infection, pneumonia) occurred within a defined time interval in one center with the same pathogen species in different patients. Four different intervals were used for calculation: 14, 30, 60, and 90 days. Infections with coagulase-negative staphylococci (CoNS) were excluded. RESULTS: A total of 228 NICUs provided data in the six-year study period. A total of 37,038 VLBW infants and 1,361,950 patient days were used for the calculation. 7,405 severe neonatal infections occurred, and a microbiological detection of the pathogen was successful in 2,084 cases. Altogether, between 121 and 280 outbreaks were calculated according to the different time intervals used. Most outbreaks were due to Staphylococcus aureus, followed by Enterococcus spp. and Enterobacter spp. CONCLUSION: It can be assumed that at least between 26 and 61 neonatal outbreaks with at least two severe infections take place in German NICUs per year. The actual number seems to be higher because only laboratory-confirmed infections in a subgroup of patients were used for the analysis.

Large multistate outbreak of norovirus gastroenteritis associated with frozen strawberries, Germany, 2012.

From 20 September through 5 October 2012, the largest recorded food-borne outbreak in Germany occurred. Norovirus was identified as the causative agent. We conducted four analytical epidemiological studies, two case­control studies and two surveys (in total 150 cases) in secondary schools in three different federal states. Overall, 390 institutions in five federal states reported nearly 11,000 cases of gastroenteritis. They were predominantly schools and childcare facilities and were supplied almost exclusively by one large catering company. The analytical epidemiological studies consistently identified dishes containing strawberries as the most likely vehicle, with estimated odds ratios ranging from 2.6 to 45.4. The dishes had been prepared in different regional kitchens of the catering company and were served in the schools two days before the peaks of the respective outbreaks. All affected institutions had received strawberries of one lot, imported frozen from China. The outbreak vehicle was identified within a week, which led to a timely recall and prevented more than half of the lot from reaching the consumer. This outbreak exemplifies the risk of large outbreaks in the era of global food trade. It underlines the importance of timely surveillance and epidemiological outbreak investigations for food safety.

Real-time fMRI neurofeedback: progress and challenges.

In February of 2012, the first international conference on real time functional magnetic resonance imaging (rtfMRI) neurofeedback was held at the Swiss Federal Institute of Technology Zurich (ETHZ), Switzerland. This review summarizes progress in the field, introduces current debates, elucidates open questions, and offers viewpoints derived from the conference. The review offers perspectives on study design, scientific and clinical applications, rtfMRI learning mechanisms and future outlook.

Differentiation between Parkinson disease and other forms of Parkinsonism using support vector machine analysis of susceptibility-weighted imaging (SWI): initial results.

OBJECTIVES: To diagnose Parkinson disease (PD) at the individual level using pattern recognition of brain susceptibility-weighted imaging (SWI). METHODS: We analysed brain SWI in 36 consecutive patients with Parkinsonism suggestive of PD who had (1) SWI at 3 T, (2) brain (123)I-ioflupane SPECT and (3) extensive neurological testing including follow-up (16 PD, 67.4 ± 6.2 years, 11 female; 20 OTHER, a heterogeneous group of atypical Parkinsonism syndromes 65.2 ± 12.5 years, 6 female). Analysis included group-level comparison of SWI values and individual-level support vector machine (SVM) analysis. RESULTS: At the group level, simple visual analysis yielded no differences between groups. However, the group-level analyses demonstrated increased SWI in the bilateral thalamus and left substantia nigra in PD patients versus other Parkinsonism. The inverse comparison yielded no supra-threshold clusters. At the individual level, SVM correctly classified PD patients with an accuracy above 86 %. CONCLUSIONS: SVM pattern recognition of SWI data provides accurate discrimination of PD among patients with various forms of Parkinsonism at an individual level, despite the absence of visually detectable alterations. This pilot study warrants further confirmation in a larger cohort of PD patients and with different MR machines and MR parameters.

Epidemiology of healthcare-associated SARS-CoV-2 outbreaks in Germany between March 2020 and May 2022.

BACKGROUND: Outbreaks in healthcare facilities played a pivotal role in the course of the coronavirus (COVID-19) pandemic. AIM: To investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks in hospitals, outpatient care, and rehabilitation facilities in Germany from March 2020 to May 2022. METHODS: Data from the German mandatory notification system were used to describe outbreaks by number of cases and case fatality ratio (CFR), and outbreak cases by age and gender. Using Pearson correlation, the dynamics of cases in the general population were compared with cases in healthcare-associated infection (HAI) SARS-CoV-2 outbreaks before and after the start of the vaccination campaign. Additionally, a counterfactual scenario was used to estimate numbers of prevented HAI cases, using the phase before vaccination as baseline. FINDINGS: By the end of May 2022, 8941 healthcare-associated outbreaks were observed with 73,626 cases: 51,504 in hospitals, 15,524 in outpatient care, and 6598 in rehabilitation facilities. Median number of cases per outbreak was 4 (range: 2-342) and cases were more frequently reported in women with 46,818 (63.6%). Overall CFR was 8.1%, higher in men (12.4%) than in women (5.7%). After the vaccination campaign was fully introduced, the association between increasing incidence in the general population and consecutive outbreak cases was decreased by a factor of 10. Furthermore, our counterfactual analysis suggests that more than 55,000 outbreak cases could have been prevented until the end of 2021. CONCLUSION: The vaccination campaign in combination with non-pharmaceutical measures was key to reduce number, size and CFR of healthcare-associated outbreaks.

Longitudinal analysis of cognitive performances and structural brain changes in late-life bipolar disorder.

OBJECTIVES: Cross-sectional studies in bipolar disorder (BD) suggested the presence of cognitive deficits and subtle magnetic resonance imaging (MRI) changes in limbic areas that may persist at euthymic stages. Whether or not cognitive and MRI changes represent stable attributes of BD or evolve with time is still matter of debate. To address this issue, we performed a 2-year longitudinal study including detailed neuropsychological and magnetic resonance imaging (MRI) analyses of 15 euthymic older BD patients and 15 controls. METHODS: Neuropsychological evaluation concerned working memory, episodic memory, processing speed, and executive functions. MRI analyses included voxel-based morphometry (VBM) analysis of gray matter including region of interest (ROI) analysis and tract-based spatial statistics (TBSS) analysis of white matter of diffusion tensor imaging derived fractional anisotropy (FA). RESULTS: BD patients displayed significantly lower performances in processing speed and episodic memory but not in working memory and executive functions compared to controls. However, BD patients did not differ from controls in the mean trajectory of cognitive changes during the 2 years follow-up. In the same line, longitudinal gray matter (VBM, ROI) and white matter (TBSS FA) changes did not differ between BD patients and controls. CONCLUSION: The lack of distinction between BD patients and controls in respect to the 2-year changes in cognition and MRI findings supports the notion that this disorder does not have a significant adverse impact on cognitive and brain aging. From this point of view, the present results convey a message of hope for patients suffering from BD.

Black holes in multiple sclerosis: definition, evolution, and clinical correlations.

Magnetic resonance imaging (MRI) is a sensitive paraclinical test for diagnosis and assessment of disease progression in multiple sclerosis (MS) and is often used to evaluate therapeutic efficacy. The formation of new T2-hyperintense MRI lesions is commonly used to measure disease activity, but lacks specificity because edema, inflammation, gliosis, and axonal loss all contribute to T2 lesion formation. As the role of neurodegeneration in the pathophysiology of MS has become more prominent, the formation and evolution of chronic or persistent Tl-hypointense lesions (black holes) have been used as markers of axonal loss and neuronal destruction to measure disease activity. Despite the use of various detection methods, including advanced imaging techniques such as magnetization transfer imaging and magnetic resonance spectroscopy, correlation of persistent black holes with clinical outcomes in patients with MS remains uncertain. Furthermore, although axonal loss and neuronal tissue destruction are known to contribute to irreversible disability in patients with MS, there are limited data on the effect of therapy on longitudinal change in Tl-hypointense lesion volume. Measurement of black holes in clinical studies may elucidate the underlying pathophysiology of MS and may be an additional method of evaluating therapeutic efficacy.

Aqueous-Based Low-Temperature Synthesis and Thin-Film Properties of Oxysulfide BiCuOS Nanoparticles.

BiCuOS is a nontoxic p-type semiconductor that is a promising candidate for photoelectric applications. The formation of thin films with a good electronic transport at the grain boundaries, while avoiding thermal treatment detrimental to its chemical stability is a challenge. We have developed a chemical method for the direct synthesis of stable colloidal suspensions of BiCuOS nanoparticles from soluble precursors. These colloidal solutions were stabilized with a catechol functionalized poly-3-hexylthiophene that allows easy spin-coating deposition and favors electronic transport along the grain boundaries. Stacking of ZnO-BiCuOS layers were achieved, allowing preparation of n-p junctions. These act as rectifying diodes and are strongly photosensitive, with Iph /Idark =85 corresponding to an enhancement of the photocurrent of more than two orders of magnitude compared to that of BiCuOS alone. This energy-efficient and low-cost method is a further step in the development of new sulfide semiconductor devices.

Resting-State Brain Activity for Early Prediction Outcome in Postanoxic Patients in a Coma with Indeterminate Clinical Prognosis.

BACKGROUND AND PURPOSE: Early outcome prediction of postanoxic patients in a coma after cardiac arrest proves challenging. Current prognostication relies on multimodal testing, using clinical examination, electrophysiologic testing, biomarkers, and structural MR imaging. While this multimodal prognostication is accurate for predicting poor outcome (ie, death), it is not sensitive enough to identify good outcome (ie, consciousness recovery), thus leaving many patients with indeterminate prognosis. We specifically assessed whether resting-state fMRI provides prognostic information, notably in postanoxic patients in a coma with indeterminate prognosis early after cardiac arrest, specifically for good outcome. MATERIALS AND METHODS: We used resting-state fMRI in a prospective study to compare whole-brain functional connectivity between patients with good and poor outcomes, implementing support vector machine learning. Then, we automatically predicted coma outcome using resting-state fMRI and also compared the prediction based on resting-state fMRI with the outcome prediction based on DWI. RESULTS: Of 17 eligible patients who completed the study procedure (among 351 patients screened), 9 regained consciousness and 8 remained comatose. We found higher functional connectivity in patients recovering consciousness, with greater changes occurring within and between the occipitoparietal and temporofrontal regions. Coma outcome prognostication based on resting-state fMRI machine learning was very accurate, notably for identifying patients with good outcome (accuracy, 94.4%; area under the receiver operating curve, 0.94). Outcome predictors using resting-state fMRI performed significantly better (P < .05) than DWI (accuracy, 60.0%; area under the receiver operating curve, 0.63). CONCLUSIONS: Indeterminate prognosis might lead to major clinical uncertainty and significant variations in life-sustaining treatments. Resting-state fMRI might bridge the gap left in early prognostication of postanoxic patients in a coma by identifying those with both good and poor outcomes.

Hyperglycaemia and pharmacokinetics of rifampicin/isoniazid among TB-HIV co-infected patients in Kampala, Uganda.

OBJECTIVE: 1) To determine the prevalence of diabetes mellitus and impaired fasting glucose (IFG) in patients with TB and HIV co-infection, and 2) to investigate the effect of fasting plasma glucose (FPG) on rifampicin (RIF) and isoniazid (INH) serum concentrations.DESIGN: Retrospective data analysis of a cohort of HIV-infected adults with newly diagnosed pulmonary TB. Plasma glucose and TB drug levels were obtained at Week 0, 2, 8 and 24 of TB treatment.RESULTS: A total of 107 patients were included in this analysis. Random plasma glucose ≥200 mg/dL was found in 1/53 (2%) participant at Week 0. The prevalence of FPG ≥ 126 mg/dL decreased from 8/41 (20%) at Week 2 to 3/89 (3%) at Week 24. IFG (100-125 mg/dL) was observed in 23/41 (56%) participants at Week 2, and 39/89 (44%) at Week 24. FPG was inversely correlated with lower area under the curve (AUC0-24h) for RIF (c = -0.52; 95%CI -0.84 to -0.21; P = 0.001). FPG was not associated with lower INH AUC0-24h.CONCLUSION: We found a high prevalence of FPG ≥ 126 mg/dL, which decreased significantly during treatment, and a high proportion of IFG at the end of TB treatment. Higher FPG was associated with lower AUC for RIF.

Impact of anti-obesity medication initiation and duration on weight loss in a comprehensive weight loss programme.

OBJECTIVE: This retrospective study aimed to evaluate the impact of anti-obesity medication (AOM) initiation, usage and duration on weight loss in a 72-week precision obesity programme. The type of AOM, diet and exercise plan was chosen based upon an individual's biological and psychosocial needs. The 72-week study duration allowed for a fair investigation of the downstream impact of delayed versus early AOM initiation. METHODS: Participants, aged ≥18 years with body mass index ≥30 kg m-2, enrolled from 1 March 2015 to 1 April 2017, were included. Subgroups were assigned by AOM usage (users versus non-users, early [before 8 weeks] versus delayed [after 8 weeks] AOM initiation and short [<6 months] versus long [≥6 months] AOM duration). Primary endpoints included change in baseline weight at 72 weeks and proportions achieving ≥5%, ≥10% and ≥15% weight loss. Outcomes were compared between subgroups. RESULTS: Mean age and body mass index (N = 129) were 45.0 ± 14.0 years and 37.0 ± 6.0 kg m-2, respectively; 67% were female. At week 72, AOM users (N = 71) achieved significantly greater mean percentage reduction in baseline weight than non-users (N = 58). On average, baseline weight decreased by 14.04 ± 6.2% in users versus 10.9 ± 6.8% in non-users (P = 0.008); 84% and 94% of non-user and AOM users lost >5% weight loss (P = 0.006). A higher proportion of users lost ≥15% of weight (45.1% vs. 19.0%; P < 0.001). Mean percentage reduction in weight was greater for early versus delayed starters (-17.60 ± 5.3% vs. -13.95 ± 5.5%; P = 0.024), and longer AOM usage trended towards increased weight loss. CONCLUSION: Early initiation of AOM may enhance weight loss.

fMRI evidence for sensorimotor transformations in human cortex during smooth pursuit eye movements.

Smooth pursuit eye movements (SP) are driven by moving objects. The pursuit system processes the visual input signals and transforms this information into an oculomotor output signal. Despite the object's movement on the retina and the eyes' movement in the head, we are able to locate the object in space implying coordinate transformations from retinal to head and space coordinates. To test for the visual and oculomotor components of SP and the possible transformation sites, we investigated three experimental conditions: (I) fixation of a stationary target with a second target moving across the retina (visual), (II) pursuit of the moving target with the second target moving in phase (oculomotor), (III) pursuit of the moving target with the second target remaining stationary (visuo-oculomotor). Precise eye movement data were simultaneously measured with the fMRI data. Visual components of activation during SP were located in the motion-sensitive, temporo-parieto-occipital region MT+ and the right posterior parietal cortex (PPC). Motor components comprised more widespread activation in these regions and additional activations in the frontal and supplementary eye fields (FEF, SEF), the cingulate gyrus and precuneus. The combined visuo-oculomotor stimulus revealed additional activation in the putamen. Possible transformation sites were found in MT+ and PPC. The MT+ activation evoked by the motion of a single visual dot was very localized, while the activation of the same single dot motion driving the eye was rather extended across MT+. The eye movement information appeared to be dispersed across the visual map of MT+. This could be interpreted as a transfer of the one-dimensional eye movement information into the two-dimensional visual map. Potentially, the dispersed information could be used to remap MT+ to space coordinates rather than retinal coordinates and to provide the basis for a motor output control. A similar interpretation holds for our results in the PPC region.

Hereditary systemic angiopathy (HSA) with cerebral calcifications, retinopathy, progressive nephropathy, and hepatopathy.

Several hereditary conditions affecting cerebral, retinal and systemic microvessels have recently been described. They include CADASIL, CRV, and HERNS. We here report on a variant form of a hereditary systemic angiopathy (HSA) affecting two generations of a Caucasian family. Clinical symptoms of HSA appear in the mid-forties and are characterized by visual impairment, migraine-like headache, skin rash, epileptic seizures, progressive motor paresis and cognitive decline. Late symptoms include hepatic and renal failure. Retinal capillary microaneurysms and arteriolar tortuosity are associated with marked optic disc atrophy. Radiological hallmarks consist of multiple cerebral calcifications and tumor-like subcortical white matter lesions. Brain, peripheral nerve, muscle, kidney and colon biopsies have revealed a multi organ small vessel involvement with partly altered endothelium, perivascular inflammation and thrombotic microangiopathy. No curative therapeutic options are known for hereditary cerebral vasculopathies. The use of cyclophosphamide, azathioprine and methotrexate was of no benefit in our cases of HSA. Early diagnosis of hereditary systemic angiopathies is important in order to prevent patients from repetitive invasive diagnostic measures and to avoid the use of inappropriate and potentially harmful drugs.

Optimization of imaging before pulmonary vein isolation by radiofrequency ablation: breath-held ungated versus ECG/breath-gated MRA.

Isolation of the pulmonary veins has emerged as a new therapy for atrial fibrillation. Pre-procedural magnetic resonance (MR) imaging enhances safety and efficacy; moreover, it reduces radiation exposure of the patients and interventional team. The purpose of this study was to optimize the MR protocol with respect to image quality and acquisition time. In 31 patients (23-73 years), the anatomy of the pulmonary veins, left atrium and oesophagus was assessed on a 1.5-Tesla scanner with four different sequences: (1) ungated two-dimensional true fast imaging with steady precession (2D-TrueFISP), (2) ECG/breath-gated 3D-TrueFISP, (3) ungated breath-held contrast-enhanced three-dimensional turbo fast low-angle shot (CE-3D-tFLASH), and (4) ECG/breath-gated CE-3D-TrueFISP. Image quality was scored from 1 (structure not visible) to 5 (excellent visibility), and the acquisition time was monitored. The pulmonary veins and left atrium were best visualized with CE-3D-tFLASH (scores 4.50 +/- 0.52 and 4.59 +/- 0.43) and ECG/breath-gated CE-3D-TrueFISP (4.47 +/- 0.49 and 4.63 +/- 0.39). Conspicuity of the oesophagus was optimal with CE-3D-TrueFISP and 2D-TrueFISP (4.59 +/- 0.35 and 4.19 +/- 0.46) but poor with CE-3D-tFLASH (1.03 +/- 0.13) (p < 0.05). Acquisition times were shorter for 2D-TrueFISP (44 +/- 1 s) and CE-3D-tFLASH (345 +/- 113 s) compared with ECG/breath-gated 3D-TrueFISP (634 +/- 197 s) and ECG/breath-gated CE-3D-TrueFISP (636 +/- 230 s) (p < 0.05). In conclusion, an MR imaging protocol comprising CE-3D-tFLASH and 2D-TrueFISP allows assessment of the pulmonary veins, left atrium and oesophagus in less than 7 min and can be recommended for pre-procedural imaging before electric isolation of pulmonary veins.

Routine screening for colonization by Gram-negative bacteria in neonates at intensive care units for the prediction of sepsis: systematic review and meta-analysis.

BACKGROUND: At neonatal intensive care units, sepsis due to Gram-negative bacteria is an important cause of morbidity and mortality. The benefits of routine microbiological screening of neonatal body surface to predict and prevent sepsis are controversial. AIM: To evaluate the prognostic value of neonatal body surface screening for colonization with Gram-negative bacteria for the prediction of late-onset sepsis. METHODS: A systematic review was performed, including studies of any design that reported data to calculate prognostic accuracy of surface screening for the prediction of late-onset sepsis. Risk of bias was assessed and a meta-analysis performed. Evidence quality was appraised using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. FINDINGS: Eight studies (all cohort design) were identified as eligible. Studies were performed in six countries in Europe, Asia, and North America and comprised a total of 4829 participants. All studies were at high risk of bias. Pooled sensitivity of body surface screening to predict late-onset sepsis was 41% (95% confidence interval: 17-70), whereas pooled specificity was 56% (34-76) (hierarchical summary receiver operating characteristics (HSROC) model). Subgroup analyses showed higher pooled estimates for specificity but not sensitivity when screening focused on Escherichia coli or Klebsiella pneumoniae. GRADE evidence quality was very low. CONCLUSION: Limited evidence of very low quality exists regarding the prognostic value of neonatal screening for late-onset sepsis. Carefully planned and conducted prospective studies, including randomized trials, are needed to clarify the potential value of this measure for the prediction and prevention of late-onset sepsis.

Brain Perfusion Measurements Using Multidelay Arterial Spin-Labeling Are Systematically Biased by the Number of Delays.

BACKGROUND AND PURPOSE: Multidelay arterial spin-labeling is a promising emerging method in clinical practice. The effect of imaging parameters in multidelay arterial spin-labeling on estimated cerebral blood flow measurements remains unknown. We directly compared 3-delay versus 7-delay sequences, assessing the difference in the estimated transit time and blood flow. MATERIALS AND METHODS: This study included 87 cognitively healthy controls (78.7 ± 3.8 years of age; 49 women). We assessed delay and transit time-uncorrected and transit time-corrected CBF maps. Data analysis included voxelwise permutation-based between-sequence comparisons of 3-delay versus 7-delay, within-sequence comparison of transit time-uncorrected versus transit time-corrected maps, and average CBF calculations in regions that have been shown to differ. RESULTS: The 7-delay sequence estimated a higher CBF value than the 3-delay for the transit time-uncorrected and transit time-corrected maps in regions corresponding to the watershed areas (transit time-uncorrected = 27.62 ± 12.23 versus 24.58 ± 11.70 mL/min/100 g, Cohen's d = 0.25; transit time-corrected = 33.48 ± 14.92 versus 30.16 ± 14.32 mL/min/100 g, Cohen's d = 0.23). In the peripheral regions of the brain, the estimated delay was found to be longer for the 3-delay sequence (1.52408 ± 0.25236 seconds versus 1.47755 ± 0.24242 seconds, Cohen's d = 0.19), while the inverse was found in the center of the brain (1.39388 ± 0.22056 seconds versus 1.42565 ± 0.21872 seconds, Cohen's d = 0.14). Moreover, 7-delay had lower hemispheric asymmetry. CONCLUSIONS: The results of this study support the necessity of standardizing acquisition parameters in multidelay arterial spin-labeling and identifying basic parameters as a confounding factor in CBF quantification studies. Our findings conclude that multidelay arterial spin-labeling sequences with a high number of delays estimate higher CBF values than those with a lower number of delays.

APOE*E4 Is Associated with Gray Matter Loss in the Posterior Cingulate Cortex in Healthy Elderly Controls Subsequently Developing Subtle Cognitive Decline.

BACKGROUND AND PURPOSE: The presence of apolipoprotein E4 (APOE*E4) is the strongest currently known genetic risk factor for Alzheimer disease and is associated with brain gray matter loss, notably in areas involved in Alzheimer disease pathology. Our objective was to assess the effect of APOE*E4 on brain structures in healthy elderly controls who subsequently developed subtle cognitive decline. MATERIALS AND METHODS: This prospective study included 382 community-dwelling elderly controls. At baseline, participants underwent MR imaging at 3T, extensive neuropsychological testing, and genotyping. After neuropsychological follow-up at 18 months, participants were classified into cognitively stable controls and cognitively deteriorating controls. Data analysis included whole-brain voxel-based morphometry and ROI analysis of GM. RESULTS: APOE*E4-related GM loss at baseline was found only in the cognitively deteriorating controls in the posterior cingulate cortex. There was no APOE*E4-related effect in the hippocampus, mesial temporal lobe, or brain areas not involved in Alzheimer disease pathology. Controls in the cognitively deteriorating group had slightly lower GM concentration in the hippocampus at baseline. Higher GM densities in the hippocampus, middle temporal lobe, and amygdala were associated with a decreased risk for cognitively deteriorating group status at follow-up. CONCLUSIONS: APOE*E4-related GM loss in the posterior cingulate cortex (an area involved in Alzheimer disease pathology) was found only in those elderly controls who subsequently developed subtle cognitive decline but not in cognitively stable controls. This finding might explain the partially conflicting results of previous studies that typically did not include detailed neuropsychological assessment and follow-up. Most important, APOE*E4 status had no impact on GM density in areas affected early by neurofibrillary tangle formation such as the hippocampus and mesial temporal lobe.

Dynamic Contrast-Enhanced MR Perfusion of Intradural Spinal Lesions.

Fifteen patients with intradural spinal lesions were examined with an optimized dynamic contrast-enhanced MR perfusion sequence at 1.5T and 3T. SNR and mean contrast-to-noise ratio were better on 3T compared with 1.5T (P ≤ .05). The goodness of fit of the Tofts and Tofts extended pharmacokinetic models was similar between 1.5T and 3T. Thus, dynamic contrast-enhanced MR perfusion of intradural spinal canal lesions is technically feasible at 1.5T and 3T, with better image quality at 3T.