Andreas Bartsch - Academia.edu (original) (raw)

Papers by Andreas Bartsch

Einleitung: In der Cochlea-Implantat-Sprechstunde stellte sich eine 21-jährige Patientin mit eine... more Einleitung: In der Cochlea-Implantat-Sprechstunde stellte sich eine 21-jährige Patientin mit einer vor wenigen Jahren akut aufgetretenen einseitigen Ertaubung vor. Tonaudiometrisch war keine Hörschwelle auf der rechten Seite bestimmbar. Otoakustische Emissionen waren jedoch vorhanden und auch[for full text, please go to the a.m. URL]

Objective: Intraoperative 1.5T high-field MRI (iMRI) is a unique imaging tool that contributes to... more Objective: Intraoperative 1.5T high-field MRI (iMRI) is a unique imaging tool that contributes to an increased extent of resection (EOR) in glioma surgery. In routine use, continued resections after iMRI are frequent and can be observed in up to 70% of cases. In this study we intended to analyze[for full text, please go to the a.m. URL]

Neuro-Oncology, 2018

NEURO-ONCOLOGY • NOVEMBER 2018 in the concurrent safety run-in phase. 2 dose-limiting toxicities ... more NEURO-ONCOLOGY • NOVEMBER 2018 in the concurrent safety run-in phase. 2 dose-limiting toxicities (DLT) were observed in 1 patient who developed both grade 3 hepatitis and pneumonitis related to atezo. 2 patients discontinued treatment during the concurrent stage due to medical complications deemed unrelated to study drug. In the 8 evaluable patients who completed the concurrent phase, no other grade 3 or 4 atezo-related toxicities were observed. 5 of the 8 evaluable patients completed the combination treatment without the need for dexamethasone. The remaining 3 of the 8 evaluable patients required no more than 4 mg daily of dexamethasone during combination treatment. All 8 patients had stable MRI findings following completion of the concurrent phase. 7 of the 8 evaluable patients proceeded with adjuvant treatment with atezo and TMZ with no grade 3 or 4 atezo-related toxicities observed to date (no. cycles range, 1-6). CONCLUSIONS: Concurrent use of atezo with radiation and TMZ was tolerable, and no new safety signals were noted. The majority of evaluable patients were able to complete the combination treatment without the need for concurrent steroid administration. The phase II component of the trial is recruiting patients (n=50) to evaluate clinical efficacy.

Journal of neurology, neurosurgery, and psychiatry, Jan 14, 2017

State-of-the-art glioma treatment aims to maximise neuro-oncological benefit while minimising los... more State-of-the-art glioma treatment aims to maximise neuro-oncological benefit while minimising losses in quality of life. Optimising this balance remains hindered by our still limited understanding of information processing in the human brain. To help understand individual differences in functional outcomes following neuro-oncological treatment, we review mounting evidence demonstrating the fundamental role that white matter connections play in complex human behaviour. We focus on selected fibre tracts whose destruction is recognised to elicit predictable behavioural deficits and consider specific indications for non-invasive diffusion MRI tractography, the only existing method to map these fibre tracts in vivo, in the selection and planning of neuro-oncological treatments. Despite remaining challenges, longitudinal tract imaging, in combination with intraoperative testing and neuropsychological evaluation, offers unique opportunities to refine our understanding of human brain organi...

Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 2001

Neurology, 2010

To study rapid-onset central motor plasticity, and its relationship to motor impairment and CNS i... more To study rapid-onset central motor plasticity, and its relationship to motor impairment and CNS injury in patients with multiple sclerosis (MS). In this cross-sectional observational study, motor plasticity was examined neurophysiologically and behaviorally in 22 patients with moderately severe (median Expanded Disability Status Scale score 2.5 [0-6]) stable MS and matched healthy controls. First, plasticity was assessed using paired associative stimulation (PAS), a protocol modeling long-term synaptic potentiation in human cortex. PAS combines repetitive electric nerve stimulation with transcranial magnetic stimulation (TMS) of the contralateral motor cortex. Second, motor learning was tested by a force production task. Motor impairment was assessed by functional tests. CNS injury was evaluated by obtaining normalized N-acetyl-aspartate (NAA/Cr) spectra using magnetic resonance spectroscopy and by the corticomuscular latency (CML) to the abductor pollicis brevis muscle as tested by TMS. Patients with MS performed worse than controls in functional motor tests, CMLs were prolonged, and NAA/Cr was decreased. PAS-induced enhancement of corticospinal excitability and training-induced increments of motor performance were comparable between patients with MS and controls. Neither PAS-induced plasticity nor motor learning performance correlated with motor impairment or measures of CNS injury. Patients with high CNS injury and good motor performance did not differ significantly from those with high CNS injury and poor motor performance with respect to PAS-induced plasticity and motor learning success. Despite motor impairment and CNS injury in patients with multiple sclerosis (MS), rapid-onset motor plasticity is comparable to that in healthy subjects. Compensation of MS-related CNS injury is unlikely to be constrained by insufficient rapid-onset neuroplasticity.

Magnetic Resonance Materials in Physics, Biology and Medicine, 2005

Conventional blood oxygenation level-dependent (BOLD) based functional magnetic resonance imaging... more Conventional blood oxygenation level-dependent (BOLD) based functional magnetic resonance imaging (fMRI) is accompanied by substantial acoustic gradient noise. This noise can influence the performance as well as neuronal activations. Conventional fMRI typically has a pulsed noise component, which is a particularly efficient auditory stimulus. We investigated whether the elimination of this pulsed noise component in a recent modification of continuous-sound fMRI modifies neuronal activations in a cognitively demanding non-auditory working memory task. Sixteen normal subjects performed a letter variant n-back task. Brain activity and psychomotor performance was examined during fMRI with continuous-sound fMRI and conventional fMRI. We found greater BOLD responses in bilateral medial frontal gyrus, left middle frontal gyrus, left middle temporal gyrus, left hippocampus, right superior frontal gyrus, right precuneus and right cingulate gyrus with continuous-sound compared to conventional fMRI. Conversely, BOLD responses were greater in bilateral cingulate gyrus, left middle and superior frontal gyrus and right lingual gyrus with conventional compared to continuous-sound fMRI. There were no differences in psychomotor performance between both scanning protocols. Although behavioral performance was not affected, acoustic gradient noise interferes with neuronal activations in non-auditory cognitive tasks and represents a putative systematic confound.

Journal of Cerebral Blood Flow & Metabolism, 2009

The effect ethanol exerts on the human brain has not yet been addressed by longitudinal magnetic ... more The effect ethanol exerts on the human brain has not yet been addressed by longitudinal magnetic resonance (MR) spectroscopic experiments. Therefore, we longitudinally characterized cerebral metabolite changes in 15 healthy individuals by proton magnetic resonance spectroscopy (1H-MRS) subsequent to the ingestion of a standard beverage (mean peak blood alcohol concentration (BAC): 51.43 ± 10.27 mg/dL). Each participant was examined before, over 93.71 ± 11.17 mins immediately after and 726.36 ± 94.96 mins (12.11 ± 1.58 h) past per os alcohol exposure. Fronto-mesial and cerebellar ethanol concentrations over time were similar as determined by the LCModel analysis of spectral data. Alcohol-induced changes of fronto-mesial creatine, choline, glucose, inositol and aspartate levels for 5.79 ± 2.94 mins upon ingestion as well as cerebellar choline and inositol levels for 8.64 ± 2.98 mins past exposure. Closely associated with ethanol concentrations, supratentorial creatine, choline, inosit...

American Journal of Psychiatry, 2000

Catatonia in depression: prevalence, clinical correlates, and validation of a scale.

Several different techniques allow a functional assessment of neuronal activations by magnetic re... more Several different techniques allow a functional assessment of neuronal activations by magnetic resonance imaging (fMRI). The by far most influential fMRI technique is based on a local T2*-sensitive hemodynamic response to neuronal activation, also known as the blood oxygenation level dependent or BOLD effect. Consequently, the term ‘fMRI' is often used synonymously with BOLD imaging. Because interpretations of fMRI brain activation maps often appear intuitive and compelling, the reader might be tempted not to critically question the fundamental processes and assumptions. We review some essential processes and assumptions of BOLD fMRI and discuss related confounds and pitfalls in fMRI - from the underlying physiological effect, to data acquisition, data analysis and the interpretation of the results including clinical fMRI. A background framework is provided for the systematic and critical interpretation of fMRI result

Clinical Neuroradiology

Diffusion echo-planar imaging (EPI) using read-out segmentation of long variable echo trains (RES... more Diffusion echo-planar imaging (EPI) using read-out segmentation of long variable echo trains (RESOLVE; [1]) has primarily been developed for high-resolution diffusion-weighted imaging with reduced susceptibilitybased geometric image distortions as well as T2*-decay related blurring and robust correction for motioninduced phase artifacts. Notably, RESOLVE also reduces the echo time (TE) but increases the scan time of the acquisitions. Simultaneous multi-slice (SMS) imaging has initiated a “new revolution” of accelerated MRI scanning [2], particularly for EPI. For diffusion EPI investigating structures with nonuniformly directed diffusion and areas of crossing fibers, like in the central nervous system, SMS principally allows to sample more diffusion directions and shells within a given acquisition time. In the peripheral nervous system with rather uniformly directed diffusion and few crossing fibers, however, substantial gains offered by SMS may be primarily related to increases in s...

Clinical Neuroradiology, Apr 9, 2020

Purpose Functional magnetic resonance imaging (fMRI) has an established role in neurosurgical pla... more Purpose Functional magnetic resonance imaging (fMRI) has an established role in neurosurgical planning; however, ambiguity surrounds the comparative value of resting and task-based fMRI relative to anatomical localization of the sensorimotor cortex. This study was carried out to determine: 1) how often fMRI adds to prediction of motor risks beyond expert neuroradiological review, 2) success rates of presurgical resting and task-based sensorimotor mapping, and 3) the impact of accelerated resting fMRI acquisitions on network detectability. Methods Data were collected at 2 centers from 71 patients with a primary brain tumor (31 women; mean age 41.9 ± 13.9 years) and 14 healthy individuals (6 women; mean age 37.9 ± 12.7 years). Preoperative 3T MRI included anatomical scans and resting fMRI using unaccelerated (TR = 3.5 s), intermediate (TR = 1.56 s) or high temporal resolution (TR = 0.72 s) sequences. Task fMRI finger tapping data were acquired in 45 patients. Group differences in fMRI reproducibility, spatial overlap and success frequencies were assessed with t-tests and χ 2-tests. Results Radiological review identified the central sulcus in 98.6% (70/71) patients. Task-fMRI succeeded in 100% (45/45). Resting fMRI failed to identify a sensorimotor network in up to 10 patients; it succeeded in 97.9% (47/48) of accelerated fMRIs, compared to only 60.9% (14/23) of unaccelerated fMRIs ((2) = 17.84, p < 0.001). Of the patients 12 experienced postoperative deterioration, largely predicted by anatomical proximity to the central sulcus. Conclusion The use of fMRI in patients with residual or intact presurgical motor function added value to uncertain anatomical localization in just a single peri-Rolandic glioma case. Resting fMRI showed high correspondence to task localization when acquired with accelerated sequences but offered limited success at standard acquisitions.

Statistical methods in medical research, 2018

Spatial resolution plays an important role in functional magnetic resonance imaging studies as th... more Spatial resolution plays an important role in functional magnetic resonance imaging studies as the signal-to-noise ratio increases linearly with voxel volume. In scientific studies, where functional magnetic resonance imaging is widely used, the standard spatial resolution typically used is relatively low which ensures a relatively high signal-to-noise ratio. However, for pre-surgical functional magnetic resonance imaging analysis, where spatial accuracy is paramount, high-resolution functional magnetic resonance imaging may play an important role with its greater spatial resolution. High spatial resolution comes at the cost of a smaller signal-to-noise ratio. This begs the question as to whether we can leverage the higher signal-to-noise ratio of a standard functional magnetic resonance imaging study with the greater spatial accuracy of a high-resolution functional magnetic resonance imaging study in a pre-operative patient. To answer this question, we propose to regress the statis...

Molecular Therapy

Oncolytic virotherapy may be a means of improving the dismal prognosis of malignant brain tumors.... more Oncolytic virotherapy may be a means of improving the dismal prognosis of malignant brain tumors. The rat H-1 parvovirus (H-1PV) suppresses tumors in preclinical glioma models, through both direct oncolysis and stimulation of anticancer immune responses. This was the basis of ParvOryx01, the first phase I/IIa clinical trial of an oncolytic parvovirus in recurrent glioblastoma patients. H-1PV (escalating dose) was administered via intratumoral or intravenous injection. Tumors were resected 9 days after treatment, and virus was re-administered around the resection cavity. Primary endpoints were safety and tolerability, virus distribution, and maximum tolerated dose (MTD). Progression-free and overall survival and levels of viral and immunological markers in the tumor and peripheral blood were also investigated. H-1PV treatment was safe and well tolerated, and no MTD was reached. The virus could cross the blood-brain/ tumor barrier and spread widely through the tumor. It showed favorable pharmacokinetics, induced antibody formation in a dose-dependent manner, and triggered specific T cell responses. Markers of virus replication, microglia/macrophage activation, and cytotoxic T cell infiltration were detected in infected tumors, suggesting that H-1PV may trigger an immunogenic stimulus. Median survival was extended in comparison with recent meta-analyses. Altogether, ParvOryx01 results provide an impetus for further H-1PV clinical development.

PloS one, 2017

Atrial fibrillation (AF) is frequently detected after ischemic stroke for the first time, and bra... more Atrial fibrillation (AF) is frequently detected after ischemic stroke for the first time, and brain regions involved in autonomic control have been suspected to trigger AF. We examined whether specific brain regions are associated with newly detected AF after ischemic stroke. Patients with acute cerebral infarctions on diffusion-weighted magnetic resonance imaging were included in this lesion mapping study. Lesions were mapped and modeled voxelwise using Bayesian Spatial Generalised Linear Mixed Modeling to determine differences in infarct locations between stroke patients with new AF, without AF and with AF already known before the stroke. 582 patients were included (median age 68 years; 63.2% male). AF was present in 109/582 patients [(18.7%); new AF: 39/109 (35.8%), known AF: 70/109 (64.2%)]. AF patients had larger infarct volumes than patients without AF (mean: 29.7 ± 45.8 ml vs. 15.2 ± 35.1 ml; p<0.001). Lesions in AF patients accumulated in the right central middle cerebral...

Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie, 1999

Zusammenfassung: Anhand von n = 133 adoleszenten Patientinnen der Berliner Anorexie-Studie belege... more Zusammenfassung: Anhand von n = 133 adoleszenten Patientinnen der Berliner Anorexie-Studie belegen Quer- und Längsschnittdaten der stationären Therapie bei Anorexia nervosa (n = 104; Achse-I-Hauptdiagnose nach ICD-10 und DSM-IV-Kriterien), Bulimia nervosa (n = 19) und atypischen Eßstörungen (n = 10) eine signifikante Verschiebung der nach dem Metrik-Index kategorisierten typologischen Häufigkeitsverteilung in Richtung leptomorpher Körperbauvarianten (p < 0.050, χ2/Fisher's). Drei Erklärungsmodelle werden diskutiert. Es wird auf die diagnostische und therapeutische Bedeutung eingegangen, insbesondere für eine körperbautypgerechte Zielgewichtsbestimmung bei Anorexia nervosa. Ein entsprechender Algorithmus unter Nutzung von Metrix-Index und geschlechtsspezifischen BMI-Altersperzentilen wird vorgeschlagen.

Nature neuroscience, Nov 19, 2016

Medical imaging has enormous potential for early disease prediction, but is impeded by the diffic... more Medical imaging has enormous potential for early disease prediction, but is impeded by the difficulty and expense of acquiring data sets before symptom onset. UK Biobank aims to address this problem directly by acquiring high-quality, consistently acquired imaging data from 100,000 predominantly healthy participants, with health outcomes being tracked over the coming decades. The brain imaging includes structural, diffusion and functional modalities. Along with body and cardiac imaging, genetics, lifestyle measures, biological phenotyping and health records, this imaging is expected to enable discovery of imaging markers of a broad range of diseases at their earliest stages, as well as provide unique insight into disease mechanisms. We describe UK Biobank brain imaging and present results derived from the first 5,000 participants' data release. Although this covers just 5% of the ultimate cohort, it has already yielded a rich range of associations between brain imaging and other...

Eur Child Adolesc Psychiatr, 2003