Submillimeter T1 atlas for subject-specific abnormality detection at 7T.

PURPOSE: Studies at 3T have shown that T1 relaxometry enables characterization of brain tissues at the single-subject level by comparing individual physical properties to a normative atlas. In this work, an atlas of normative T1 values at 7T is introduced with 0.6 mm isotropic resolution and its clinical potential is explored in comparison to 3T. METHODS: T1 maps were acquired in two separate healthy cohorts scanned at 3T and 7T. Using transfer learning, a template-based brain segmentation algorithm was adapted to ultra-high field imaging data. After segmenting brain tissues, volumes were normalized into a common space, and an atlas of normative T1 values was established by modeling the T1 inter-subject variability. A method for single-subject comparisons restricted to white matter and subcortical structures was developed by computing Z-scores. The comparison was applied to eight patients scanned at both field strengths for proof of concept. RESULTS: The proposed method for morphometry delivered segmentation masks without statistically significant differences from those derived with the original pipeline at 3T and achieved accurate segmentation at 7T. The established normative atlas allowed characterizing tissue alterations in single-subject comparisons at 7T, and showed greater anatomical details compared with 3T results. CONCLUSION: A high-resolution quantitative atlas with an adapted pipeline was introduced and validated. Several case studies on different clinical conditions showed the feasibility, potential and limitations of high-resolution single-subject comparisons based on quantitative MRI atlases. This method in conjunction with 7T higher resolution broadens the range of potential applications of quantitative MRI in clinical practice.

Diffusion tensor imaging in unclear intramedullary tumor-suspected lesions allows separating tumors from inflammation.

DESIGN: Prospective diagnostic study. OBJECTIVES: Primary imaging-based diagnosis of spinal cord tumor-suspected lesions is often challenging. The identification of the definite entity is crucial for dedicated treatment and therefore reduction of morbidity. The aim of this trial was to investigate specific quantitative signal patterns to differentiate unclear intramedullary tumor-suspected lesions based on diffusion tensor imaging (DTI). SETTING: Medical Center - University of Freiburg, Germany. METHODS: Forty patients with an unclear tumor-suspected lesion of the spinal cord prospectively underwent DTI. Primary diagnosis was determined by histological or clinical work-up or remained indeterminate with follow-up. DTI metrics (FA/ADC) were evaluated at the central lesion area, lesion margin, edema, and normal spinal cord and compared between different diagnostic groups (ependymomas, other spinal cord tumors, inflammations). RESULTS: Mean DTI metrics for all spinal cord tumors (n = 18) showed significantly reduced FA and increased ADC values compared to inflammatory lesions (n = 8) at the lesion margin (p < 0.001, p = 0.001) and reduced FA at the central lesion area (p < 0.001). There were no significant differences comparing the neoplastic subgroups of ependymomas (n = 10) and other spinal cord tumors (n = 8), but remaining differences for both compared to the inflammation subgroup. We found significant higher ADC (p = 0.040) and a trend to decreased FA (p = 0.081) for ependymomas compared to inflammations at the edema. CONCLUSION: Even if distinct differentiation of ependymomas from other spinal cord neoplasms was not possible based on quantitative DTI metrics, FA and ADC were feasible to separate inflammatory lesions. This may avoid unnecessary surgery in patients with unclear intramedullary tumor-suspected lesions.

3D X-ray based visualization of directional deep brain stimulation lead orientation.

Knowing the orientation of directional deep brain stimulation electrodes enables imaging-based adjustment of the stimulation settings. A rotational X-ray based examination was developed to determine the electrodes orientation. By identifying the patient´s 0° axis and the electrode´s rotation using the "iron sights"-sign, the exact orientation of the electrode in relation to the ACPC-line is given. The presented imaging approach offers a reliable diagnostic tool for visualization of the implanted DBS electrode orientation in clinical routine.

The ventral pathway of the human brain: A continuous association tract system.

The brain hemispheres can be divided into an upper dorsal and a lower ventral system. Each system consists of distinct cortical regions connected via long association tracts. The tracts cross the central sulcus or the limen insulae to connect the frontal lobe with the posterior brain. The dorsal stream is associated with sensorimotor mapping. The ventral stream serves structural analysis and semantics in different domains, as visual, acoustic or space processing. How does the prefrontal cortex, regarded as the platform for the highest level of integration, incorporate information from these different domains? In the current view, the ventral pathway consists of several separate tracts, related to different modalities. Originally the assumption was that the ventral path is a continuum, covering all modalities. The latter would imply a very different anatomical basis for cognitive and clinical models of processing. To further define the ventral connections, we used cutting-edge in vivo global tractography on high-resolution diffusion tensor imaging (DTI) data from 100 normal subjects from the human connectome project and ex vivo preparation of fiber bundles in the extreme capsule of 8 humans using the Klingler technique. Our data showed that ventral stream tracts, traversing through the extreme capsule, form a continuous band of fibers that fan out anteriorly to the prefrontal cortex, and posteriorly to temporal, occipital and parietal cortical regions. Introduction of additional volumes of interest in temporal and occipital lobes differentiated between the inferior fronto-occipital fascicle (IFOF) and uncinate fascicle (UF). Unequivocally, in both experiments, in all subjects a connection between the inferior frontal and middle-to-posterior temporal cortical region, otherwise known as the temporo-frontal extreme capsule fascicle (ECF) from nonhuman primate brain-tracing experiments was identified. In the human brain, this tract connects the language domains of "Broca's area" and "Wernicke's area". The differentiation in the three tracts, IFOF, UF and ECF seems arbitrary, all three pass through the extreme capsule. Our data show that the ventral pathway represents a continuum. The three tracts merge seamlessly and streamlines showed considerable overlap in their anterior and posterior course. Terminal maps identified prefrontal cortex in the frontal lobe and association cortex in temporal, occipital and parietal lobes as streamline endings. This anatomical substrate potentially facilitates the prefrontal cortex to integrate information across different domains and modalities.

[Interdisciplinary networking for optimal treatment decision-making : Fast decision-making in acute ischemic stroke management]. / Mittels interdisziplinärer Vernetzung zur optimalen Therapieentscheidung : Der schnelle Weg zur Therapieentscheidung beim akuten Schlaganfall.

Every year, about 270,000 strokes occur in Germany. In the entire DACH region (Germany, Austria, Switzerland), more than 310,000 cases are reported each year. Two thirds of the surviving patients are dependent on external assistance after the stroke. Increasingly, imaging data are becoming the focus of treatment decisions. These data provide critical information about the location and extent of vessel occlusion, infarct size, volume of salvageable brain tissue, and degree of collateralization. Certified stroke units and stroke networks already specialize in state-of-the-art therapeutic options, but they need additional information technology tools to deliver the right therapy to the right patient population as quickly as possible. For multidisciplinary, seamless support in stroke care, both prehospital and in-hospital processes need to be optimized. This article presents a concept for supraregional stroke care by means of networking all involved actors in the prehospital as well as in the in-hospital area. Further needs analyses should ensure the implementation as well as the generalizability to different regions.

Impact of Stereotactic Ventriculocisternostomy on Delayed Cerebral Infarction and Outcome After Subarachnoid Hemorrhage.

Background and Purpose- Delayed cerebral infarction (DCI) is an important cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). Stereotactic catheter ventriculocisternostomy (STX-VCS) and fibrinolytic/spasmolytic lavage is a new method for DCI prevention. Here, we assess the effects of implementing STX-VCS in an unselected aSAH patient population of a tertiary referral center. Methods- Retrospective cohort study of all consecutive aSAH patients admitted to a neurosurgical referral center during a 7-year period (April 2012 to April 2019). Midterm STX-VCS was introduced and offered to patients at high risk for DCI. We compared the incidence and burden of DCI, neurological outcome, and the use of induced hypertension and endovascular rescue therapy in this consecutive aSAH population 3.5 years before versus 3.5 years after STX-VCS became available. Results- Four hundred thirty-six consecutive patients were included: 222 BEFORE and 214 AFTER. Fifty-seven of 214 (27%) patients received STX-VCS. Stereotactic procedures resulted in one (2%) subdural hematoma. Favorable neurological outcome at 6 months occurred in 118 (53%) patients BEFORE and 139 (65%) patients AFTER (relative risk, 0.79 [95% CI, 0.66-0.95]). DCI occurred in 40 (18.0%) patients BEFORE and 17 (7.9%) patients AFTER (relative risk, 0.68 [95% CI, 0.57-0.86]), and total DCI volumes were 8933 (100%) and 3329 mL (36%), respectively. Induced hypertension was used in 97 (44%) and 30 (15%) patients, respectively (relative risk, 0.55 [95% CI, 0.46-0.65]). Thirty (13.5%) patients BEFORE versus 5 (2.3%) patients AFTER underwent endovascular rescue therapies (relative risk, 0.17 [95% CI, 0.07-0.42]). Conclusions- Selecting high-risk patients for STX-VCS reduced the DCI incidence, burden, and related mortality in a consecutive aSAH patient population. This was associated with an improved neurological outcome.

Hippocampus-avoidance whole-brain radiation therapy with a simultaneous integrated boost for multiple brain metastases.

BACKGROUND: The current study was aimed at investigating the feasibility of hippocampus-avoidance whole-brain radiation therapy with a simultaneous integrated boost (HA-WBRT+SIB) for metastases and at assessing tumor control in comparison with conventional whole-brain radiation therapy (WBRT) in patients with multiple brain metastases. METHODS: Between August 2012 and December 2016, 66 patients were treated within a monocentric feasibility trial with HA-WBRT+SIB: hippocampus-avoidance WBRT (30 Gy in 12 fractions, dose to 98% of the hippocampal volume ≤ 9 Gy) and a simultaneous integrated boost (51 or 42 Gy in 12 fractions) for metastases/resection cavities. Intracranial tumor control, hippocampal failure, and survival were subsequently compared with a retrospective cohort treated with WBRT via propensity score matching analysis. RESULTS: After 1:1 propensity score matching, there were 62 HA-WBRT+SIB patients and 62 WBRT patients. Local tumor control (LTC) of existing metastases was significantly higher after HA-WBRT+SIB (98% vs 82% at 1 year; P = .007), whereas distant intracranial tumor control was significantly higher after WBRT (82% vs 69% at 1 year; P = .016); this corresponded to higher biologically effective doses. Intracranial progression-free survival (PFS; 13.5 vs 6.4 months; P = .03) and overall survival (9.9 vs 6.2 months; P = .001) were significantly better in the HA-WBRT+SIB cohort. Four patients (6.5%) developed hippocampal metastases after hippocampus avoidance. The neurologic death rate after HA-WBRT+SIB was 27.4%. CONCLUSIONS: HA-WBRT+SIB can be an efficient therapeutic option for patients with multiple brain metastases and is associated with improved LTC of existing metastases, higher intracranial PFS, a reduction of the neurologic death rate, and an acceptable risk of radiation necrosis. The therapy has the potential to prevent neurocognitive adverse effects, which will be further evaluated in the multicenter, phase 2 HIPPORAD trial.

Whole-brain irradiation with hippocampal sparing and dose escalation on metastases: neurocognitive testing and biological imaging (HIPPORAD) - a phase II prospective randomized multicenter trial (NOA-14, ARO 2015-3, DKTK-ROG).

BACKGROUND: Whole brain radiation therapy (WBRT) is the standard therapy for multiple brain metastases. However, WBRT has a poor local tumor control and is associated with a decline in neurocognitive function (NCF). Aim of this trial is to assess the efficacy and safety of a new treatment method, the WBRT with hippocampus avoidance (HA) combined with the simultaneous integrated boost (SIB) on metastases/resection cavities (HA-WBRT+SIB). METHODS: This is a prospective, randomized, two-arm phase II multicenter trial comparing the impact of HA on NCF after HA-WBRT+SIB versus WBRT+SIB in patients with multiple brain metastases. The study design is double-blinded. One hundred thirty two patients are to be randomized with a 1:1 allocation ratio. Patients between 18 and 80 years old are recruited, with at least 4 brain metastases of solid tumors and at least one, but not exceeding 10 metastases ≥5 mm. Patients must be in good physical condition and have no metastases/resection cavities in or within 7 mm of the hippocampus. Patients with dementia, meningeal disease, cerebral lymphomas, germ cell tumors, or small cell carcinomas are excluded. Previous irradiation and resection of metastases, as well as the number and size of metastases to be boosted have to comply with certain restrictions. Patients are randomized between the two treatment arms: HA-WBRT+SIB and WBRT+SIB. WBRT is to be performed with 30 Gy in 12 daily fractions and the SIB with 51 Gy/42 Gy in 12 daily fractions on 95% of volume for metastases/resection cavities. In the experimental arm, the dose to the hippocampi is restricted to 9 Gy in 98% of the volume and 17Gy in 2% of the volume. NCF testing is scheduled before WBRT, after 3 (primary endpoint), 9, 18 months and yearly thereafter. Clinical and imaging follow-ups are performed 6 and 12 weeks after WBRT, after 3, 9, 18 months and yearly thereafter. DISCUSSION: This is a protocol of a randomized phase II trial designed to test a new strategy of WBRT for preventing cognitive decline and increasing tumor control in patients with multiple brain metastases. TRIAL REGISTRATION: The HIPPORAD trial is registered with the German Clinical Trials Registry (DRKS00004598, registered 2 June 2016).

[MRI in Neurodegenerative Diseases]. / MRT bei neurodegenerativen Erkrankungen.

According to the German S3 guideline dementia every patient with a dementia disorder should have a MRI. The goal is not only to uncover treatable conditions but also to detect region-specific atrophy pattern which are characteristic of primary dementia disorders such as Alzheimer's disease, fronto-temporal lobar degeneration and others. Diagnostic accuracy can be improved by Voxel- and Region-based volumetric analysis of the individual brain compared to age-matched controls.

Effect of a liberal versus a restrictive pre-donation blood pressure policy on whole-blood donor adverse reactions.

BACKGROUND AND OBJECTIVES: The role of pre-donation blood pressure (BP) as independent contributor to post-donation vasovagal reactions (VVRs) is still debated. Differences between a liberal (i.e., inclusion of hypotensive donors) and a restrictive policy (i.e., not accepting hypotensive donors) should be investigated. This study aims to investigate the consequences of a liberal policy in development of VVRs after whole-blood donations. MATERIALS AND METHODS: We compared the incidence of VVRs between 2015 (restrictive policy) and 2016 (liberal policy) and the associated risk factors. We evaluated respectively 22 789 vs. 21 676 blood donations obtained from 18 001 blood donors (12 501 donated in both years). RESULTS: Comparing the results we obtained between 2015 and 2016, donations showed an overlap of the cohorts. Two hundred fifteen VVRs (incidence rate 0·48%) were observed, 104 (0·46%) of which in 2015, and 111 (0·51%) in 2016. A preliminary univariate analysis showed that donors with systolic BP <110 mm Hg had a two-fold risk of VVRs compared to normotensive donors (VVR/donation rate of 0·99% vs. 0·46%; P = 0·001). The subsequent multivariable logistic regression model showed that VVRs were highly associated with weight, site of collection, age and number of donations, excluding a role for systolic and diastolic BP. CONCLUSION: A liberal pre-donation BP policy seems to be safe for blood donors. Our analysis confirms that older donors with higher body-weight who already had donated blood are unlikely to experience VVRs.

Association between seizure freedom and default mode network reorganization in patients with unilateral temporal lobe epilepsy.

RATIONALE: The spontaneous synchronized activity and intrinsic organization of the Default Mode Network (DMN) has been found to be altered because of epileptic activity of temporal lobe origin. Thus, the aim of the present study was to compare DMN's topological properties in patients with seizure-free (SF) and not seizure-free (NSF) temporal lobe epilepsy (TLE). METHODS: Functional connectivity within the DMN was determined from an 8-minute resting state functional magnetic resonance imaging (fMRI) in 27 patients with TLE (12 SF, 15 NSF) and 15 healthy controls (HC). The DMN regions of interest were extracted according to the automated anatomical labeling (AAL) atlas. Network properties were assessed using standard graph-theoretical measures. RESULTS: Analyses revealed, irrespectively of focus lateralization, borderline significance for longer paths (p = 0.049) and in trend reduced local efficiency within the DMN of SF when compared with that of NSF (p = 0.075). The SF and NSF patients did not differ in global network topology from HC (p > 0.05). At the nodal network level, the degree of central hubs was significantly reduced in SF when compared with that in NSF (0.002 ≤ p ≤ 0.080) and HC (0.001 ≤ p ≤ 0.066) while simultaneously, right anterior superior temporal gyrus revealed significantly higher degree in SF than in NSF (p = 0.005) and HC (p = 0.016). CONCLUSION: Seizure freedom seems to be associated with hub redistributions that may underlie longer paths and (in trend) reduced local efficiency of the network. An associated slower system response might reduce the probability of a rapid spread of epileptic discharges over the whole network and may help to prevent hypersynchronous neuronal activity in brain networks that may result in epileptic seizures.

Probing the reproducibility of quantitative estimates of structural connectivity derived from global tractography.

As quantitative measures derived from fiber tractography are increasingly being used to characterize the structural connectivity of the brain, it is important to establish their reproducibility. However, no such information is as yet available for global tractography. Here we provide the first comprehensive analysis of the reproducibility of streamline counts derived from global tractography as quantitative estimates of structural connectivity. In a sample of healthy young adults scanned twice within one week, within-session and between-session test-retest reproducibility was estimated for streamline counts of connections based on regions of the AAL atlas using the intraclass correlation coefficient (ICC) for absolute agreement. We further evaluated the influence of the type of head-coil (12 versus 32 channels) and the number of reconstruction repetitions (reconstructing streamlines once or aggregated over ten repetitions). Factorial analyses demonstrated that reproducibility was significantly greater for within- than between-session reproducibility and significantly increased by aggregating streamline counts over ten reconstruction repetitions. Using a high-resolution head-coil incurred only small beneficial effects. Overall, ICC values were positively correlated with the streamline count of a connection. Additional analyses assessed the influence of different selection variants (defining fuzzy versus no fuzzy borders of the seed mask; selecting streamlines that end in versus pass through a seed) showing that an endpoint-based variant using fuzzy selection provides the best compromise between reproducibility and anatomical specificity. In sum, aggregating quantitative indices over repeated estimations and higher numbers of streamlines are important determinants of test-retest reproducibility. If these factors are taken into account, streamline counts derived from global tractography provide an adequately reproducible quantitative measure that can be used to gauge the structural connectivity of the brain in health and disease.

Regional neuronal activity in patients with relapsing remitting multiple sclerosis.

OBJECTIVES: Although interferon-beta is an established drug for relapsing remitting multiple sclerosis (RRMS), its impact on neuronal activity is not well understood. METHODS: We investigated 15 patients with RRMS by [18 F]fluorodeoxyglucose positron emission tomography (FDG-PET) to assess cerebral metabolic rate of glucose (CMRglc ) before interferon-beta therapy. Further, we performed clinical and neuropsychological investigations. In nine patients, these investigations were repeated after 6 months of therapy. Ten healthy controls were also studied. RESULTS: We found no significant differences in absolute CMRglc between patients and controls, or in patients before and during treatment. However, during treatment, relative regional glucose metabolism (rCMRlglc ) was decreased in cerebellum and increased in parts of left inferior parietal, temporo-occipital, frontal cortical areas, left striatum and right insula. In untreated patients, higher fatigue was associated with lower rCMRlglc in portions of left posterior cingulate cortex, and higher depression was associated with lower rCMRlglc within the left superior temporal sulcus. In the pooled sample, higher depression was associated with higher rCMRlglc in parts of the right precuneus. CONCLUSIONS: Our results indicate effects of IFN-beta treatment on cerebellar, cortical and subcortical neuronal function. Moreover, more severe fatigue and depression in untreated patients seem to be associated with reduced neuronal activity in left posterior cingulate cortex and left superior temporal cortex, respectively.

Combination of CT angiography and MRI in surgical planning of deep brain stimulation.

PURPOSE: For safe deep brain stimulation (DBS) planning, an accurate visualization and localization of vessels is mandatory. Contrast enhanced (ce) MRI depicts both arteries and veins. Computed tomography angiography (CTA) detects arteries with high geometric accuracy. We routinely combine both modalities for DBS planning. METHODS: A total of 222 trajectories in a consecutive series of 113 patients who underwent DBS operations were included. In all trajectories, the number of veins and arteries in a 10-mm diameter around the planned trajectory were counted in a ceMRI and a CTA. If a vessel was visible in both modalities, the distance was measured. RESULTS: A total of 370 vessels were counted. Two hundred forty vessels (65%) were visible in both modalities. With 134 of the vessels, we detected a difference of the vessel's location with an average distance of 1.24 mm (SD 0.58). Eighty vessels (22%) were visible only in the ceMRI, 50 vessels (13%) only in the CTA. We had four bleedings (1.8% per lead) of which one was symptomatic (0.45%). CONCLUSION: The majority of vessels were visible in both modalities; however, in more than half of these cases, the location was not identical. Here, the location in the CTA can be regarded as the ground truth. Moreover, both the CTA and the ceMRI depicted vessels not seen in the other imaging modality. We therefore assume that the combination of both imaging modalities for DBS planning increases the chance to detect vascular conflicts along the trajectory, thus reducing the risk of intracranial bleeding.

Development of a Standardized Cranial Phantom for Training and Optimization of Functional Stereotactic Operations.

BACKGROUND: In recent years, simulations based on phantom models have become increasingly popular in the medical field. In the field of functional and stereotactic neurosurgery, a cranial phantom would be useful to train operative techniques, such as stereo-electroencephalography (SEEG), to establish new methods as well as to develop and modify radiological techniques. In this study, we describe the construction of a cranial phantom and show examples for it in stereotactic and functional neurosurgery and its applicability with different radiological modalities. METHODS: We prepared a plaster skull filled with agar. A complete operation for deep brain stimulation (DBS) was simulated using directional leads. Moreover, a complete SEEG operation including planning, implantation of the electrodes, and intraoperative and postoperative imaging was simulated. RESULTS: An optimally customized cranial phantom is filled with 10% agar. At 7°C, it can be stored for approximately 4 months. A DBS and an SEEG procedure could be realistically simulated. Lead artifacts can be studied in CT, X-ray, rotational fluoroscopy, and MRI. CONCLUSIONS: This cranial phantom is a simple and effective model to simulate functional and stereotactic neurosurgical operations. This might be useful for teaching and training of neurosurgeons, establishing operations in a new center and for optimization of radiological examinations.

Stereotactic Catheter Ventriculocisternostomy for Clearance of Subarachnoid Hemorrhage: A Matched Cohort Study.

BACKGROUND AND PURPOSE: Delayed cerebral infarction (DCI) is a major source of morbidity and mortality after aneurysmal subarachnoid hemorrhage. We report a novel intervention-stereotactic catheter ventriculocisternostomy (STX-VCS) and fibrinolytic/spasmolytic lavage therapy-for DCI prevention. Outcomes of 20 consecutive patients are compared with 60 matched controls. METHODS: On the basis of individual treatment decisions, STX-VCS was performed in 20 high-risk aneurysmal subarachnoid hemorrhage patients admitted to our department between September 2015 and October 2016. Three controls matched for age, sex, aneurysm treatment method, and admission Hunt and Hess grade were assigned to each case treated by STX-VCS. DCI was the primary outcome. Mortality and mRS at rehabilitation discharge were secondary outcome parameters. The association between STX-VCS and DCI, mortality, and mRS was assessed by conditional logistic regression. RESULTS: Stereotactic procedures were performed without surgical complications. Continuous cisternal lavage was feasible in 17 of 20 patients (85%). One adverse event because of cisternal lavage was without sequelae. DCI occurred in 25 of 60 (42%) controls and 3 of 20 (15%) patients with STX-VCS (odds ratio, 0.15; 95% confidence interval, 0.04-0.64). Mortality occurred in 20 of 60 (33%) controls and 1 of 20 (5%) patients with STX-VCS, respectively (odds ratio, 0.08; 95% confidence interval, 0.01 - 0.66). Favorable outcome (mRS≤3) at rehabilitation discharge was observed in 12 of 20 patients with STX-VCS (60%) versus 21 of 60 (35%) matched controls (odds ratio, 0.26; 95% confidence interval, 0.8-0.86). CONCLUSIONS: STX-VCS was feasible and safe in patients with severe aneurysmal subarachnoid hemorrhage. Initial results indicate that DCI and mortality can be reduced, and neurological outcome may be improved with this method.

Manual MRI morphometry in Parkinsonian syndromes.

BACKGROUND: Several morphometric magnetic resonance imaging parameters may serve for differential diagnosis of parkinsonism. The objective of this study was to identify which performs best in clinical routine. METHODS: We acquired multicentric magnetization-prepared rapid gradient echo sequences in patients with Parkinson's disease (n=204), progressive supranuclear palsy (n=106), multiple system atrophy-cerebellar, (n = 21); multiple system atrophy-parkinsonian (n = 60), and healthy controls (n = 73), performed manual planimetric measurements, and calculated receiver operator characteristics with leave-one-out cross-validation to propose cutoff values. RESULTS: The midsagittal midbrain area was reduced in PSP versus all other groups (P < 0.001). The midsagittal pons area was reduced in MSA-cerebellar, MSA-parkinsonian, and PSP versus PD patients and healthy controls (P < 0.001). The midbrain/pons area ratio was lower in PSP (P < 0.001) and higher in MSA-cerebellar and MSA-parkinsonian versus PD and PSP (P < 0.001). CONCLUSIONS: The midsagittal midbrain area most reliably identified PSP, the midsagittal pons area MSA-cerebellar. The midbrain/pons area ratio differentiated MSA-cerebellar and PSP better than the magnetic resonance-Parkinson index. © 2017 International Parkinson and Movement Disorder Society.

Arterial spin labeling-based Z-maps have high specificity and positive predictive value for neurodegenerative dementia compared to FDG-PET.

OBJECTIVE: Cerebral perfusion analysis based on arterial spin labeling (ASL) MRI has been proposed as an alternative to FDG-PET in patients with neurodegenerative disease. Z-maps show normal distribution values relating an image to a database of controls. They are routinely used for FDG-PET to demonstrate disease-specific patterns of hypometabolism at the individual level. This study aimed to compare the performance of Z-maps based on ASL to FDG-PET. METHODS: Data were combined from two separate sites, each cohort consisting of patients with Alzheimer's disease (n = 18 + 7), frontotemporal dementia (n = 12 + 8) and controls (n = 9 + 29). Subjects underwent pseudocontinuous ASL and FDG-PET. Z-maps were created for each subject and modality. Four experienced physicians visually assessed the 166 Z-maps in random order, blinded to modality and diagnosis. RESULTS: Discrimination of patients versus controls using ASL-based Z-maps yielded high specificity (84%) and positive predictive value (80%), but significantly lower sensitivity compared to FDG-PET-based Z-maps (53% vs. 96%, p < 0.001). Among true-positive cases, correct diagnoses were made in 76% (ASL) and 84% (FDG-PET) (p = 0.168). CONCLUSION: ASL-based Z-maps can be used for visual assessment of neurodegenerative dementia with high specificity and positive predictive value, but with inferior sensitivity compared to FDG-PET. KEY POINTS: • ASL-based Z-maps yielded high specificity and positive predictive value in neurodegenerative dementia. • ASL-based Z-maps had significantly lower sensitivity compared to FDG-PET-based Z-maps. • FDG-PET might be reserved for ASL-negative cases where clinical suspicion persists. • Findings were similar at two study sites.

Visual neglect after left-hemispheric lesions: a voxel-based lesion-symptom mapping study in 121 acute stroke patients.

Visual neglect after left-hemispheric lesion is thought to be less frequent, less severe, and shorter lived than visuospatial attention deficits resulting from right-hemispheric lesions. However, reports exist opposing this assumption, and it is unclear how these findings fit into the current theories of visuospatial processing. Furthermore, only little is known about the exact structure-function relationship between visuospatial attention deficits and left-hemispheric stroke. We investigated neglect in 121 patients with acute left-hemispheric ischemic stroke by following clinical development from within the first 24 h of stroke onset until hospital discharge. Visuospatial attention deficits occurred in 17.4 % (n = 21). Voxel-based lesion-symptom mapping associated visual neglect to the right with lesion in the left superior and middle temporal gyrus, temporal pole, frontal operculum, and insula. Neglect severity, captured by the Center of Cancellation Score of the Bells test, was associated with lesion in the left anterior temporal lobe and the left frontal operculum. The left-hemispheric lesion pattern of neglect thus involves areas of the ventral attention system and partly mirrors the critical regions of the right hemisphere known to be associated with neglect. Based on our prospective analysis on a large cohort of patients with left-hemispheric stroke, this study shows that in a remarkable number of patients, the left hemisphere essentially contributes to an intact representation of space and clarifies the impact of the distinct left-hemispheric structures involved in visuospatial processing.

Visual field defects following different resective procedures for mesiotemporal lobe epilepsy.

INTRODUCTION: One of the most common side effects of mesiotemporal lobe resection in patients with medically intractable epilepsy are visual field defects (VFD). While peripheral defects usually remain unnoticed by patients, extended VFD influence daily life activities and can, in particular, affect driving regulations. This study had been designed to evaluate frequency and extent of VFD following different surgical approaches to the mesiotemporal area with respect to the ability to drive. MATERIALS AND METHODS: This study comprises a consecutive series of 366 patients operated at the Epilepsy Center in Freiburg for intractable mesiotemporal lobe epilepsy from 1998 to 2016. The following procedures were performed: standard anterior temporal lobectomy (ATL: n=134; 37%), anterior temporal or keyhole resection (KH: n=53; 15%), and selective amygdalohippocampectomy via the transsylvian (tsAHE: n=145; 40%) and the subtemporal (ssAHE: n=34; 9%) approach. Frequency and extent of postoperative VFD were evaluated in relation to different surgical procedures. According to the German driving guidelines, postoperative VFD were classified as driving-relevant VFD with the involvement of absolute, homonymous central scotoma within 20° and driving-irrelevant VFD with either none or exclusively minor VFD sparing the center. RESULTS: Postoperative visual field examinations were available in 276 of 366 cases. Postoperative VFD were observed in 202 of 276 patients (73%) and were found to be driving-relevant in 133 of 276 patients (48%), whereas 69 patients (25%) showed VFD irrelevant for driving. Visual field defects were significantly less likely following ssAHE compared with other temporal resections, and if present, they were less frequently driving-relevant (p<0.05), irrespective of the side of surgery. CONCLUSION: Subtemporal sAHE (ssAHE) caused significantly less frequently and less severely driving-relevant VFD compared with all other approaches to the temporal lobe, irrespective of the side of surgery.