Publications by authors named "Karl-Titus Hoffmann"

122 Publications

Flow Diversion for Reconstruction of Intradural Vertebral Artery Dissecting Aneurysms Causing Subarachnoid Hemorrhage-A Retrospective Study From Four Neurovascular Centers.

Front Neurol 2021 1;12:700164. Epub 2021 Jul 1.

Department of Neuroradiology, Radiology and Policlinic of Radiology, University Hospital Halle (Saale), Halle, Germany.

Dissecting aneurysms (DAs) of the vertebrobasilar territory manifesting with subarachnoid hemorrhage (SAH) are associated with significant morbi-mortality, especially in the case of re-hemorrhage. Sufficient reconstruction of the affected vessel is paramount, in particular, if a dominant vertebral artery (VA) is impacted. Reconstructive options include stent-assisted coiling and flow diversion (FD). The latter is technically less challenging and does not require catheterization of the fragile aneurysm. Our study aims to report a multicentric experience with FD for reconstruction of DA in acute SAH. This retrospective study investigated 31 patients (age: 30-78 years, mean 55.5 years) who had suffered from SAH due to a DA of the dominant VA. The patients were treated between 2010 and 2020 in one of the following German neurovascular centers: University Hospital Leipzig, Katharinenhospital Stuttgart, BG Hospital Bergmannstrost Halle/Saale, and Heinrich-Braun-Klinikum Zwickau. Clinical history, imaging, implanted devices, and outcomes were reviewed for the study. Reconstruction with flow-diverting stents was performed in all cases. The p64 was implanted in 14 patients; one of them required an additional balloon-expandable stent to reconstruct severe stenosis in the target segment. One case demanded additional liquid embolization after procedural rupture, and in one case, p64 was combined with a PED. Further 13 patients were treated exclusively with the PED. The p48MW-HPC was used in two patients, one in combination with two additional Silk Vista Baby (SVB). Moreover, one patient was treated with a single SVB, one with a SILK+. Six patients died [Glasgow Outcome Scale (GOS) 1]. Causes of death were periprocedural re-hemorrhage, thrombotic occlusion of the main pulmonary artery, and delayed parenchymal hemorrhage. The remaining three patients died in the acute-subacute phase related to the severity of the initial hemorrhage and associated comorbidities. One patient became apallic (GOS 2), whereas two patients had severe disability (GOS 3) and four had moderate disability (GOS 4). Eighteen patients showed a complete recovery (GOS 5). Reconstruction of VA-DA in acute SAH with flow-diverting stents is a promising approach. However, the severity of the condition is reflected by high overall morbi-mortality, even despite technically successful endovascular treatment.
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http://dx.doi.org/10.3389/fneur.2021.700164DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8280292PMC
July 2021

Endovascular Treatment of Intracranial Aneurysms in Small Peripheral Vessel Segments-Efficacy and Intermediate Follow-Up Results of Flow Diversion With the Silk Vista Baby Low-Profile Flow Diverter.

Front Neurol 2021 28;12:671915. Epub 2021 May 28.

Department of Neuroradiology, Clinic & Policlinic of Radiology, University Hospital Halle, Halle (Saale), Germany.

Low-profile flow diverter stents (FDS) quite recently amended peripheral segments as targets for hemodynamic aneurysm treatment; however, reports on outcomes, especially later than 3 months, are scarce. This study therefore reports our experience with the novel silk vista baby (SVB) FDS and respective outcomes after 8 and 11 months with special respect to specific adverse events. Forty-four patients (mean age, 53 years) harboring 47 aneurysms treated with the SVB between June 2018 and December 2019 were included in our study. Clinical, procedural, and angiographic data were collected. Follow-ups were performed on average after 3, 8, and 11 months, respectively. Treatment effect was assessed using the O'Kelly Marotta (OKM) grading system. Overall, angiographic follow-ups were available for 41 patients/45 aneurysms. Occlusion or significant reduction in aneurysmal perfusion (OKM: D1, B1-B3 and A2-A3) was observed in 98% of all aneurysms after 8 months. Only 2% of the treated aneurysms remained morphologically unaltered and without an apparent change in perfusion (OKM A1). Adverse events in the early post-interventional course occurred in seven patients; out of them, mRS-relevant morbidity at 90 days related to FDS treatment was observable in two patients. One death occurred in the context of severe SAH related to an acutely ruptured dissecting aneurysm of the vertebral artery. The SVB achieves sufficient occlusion rates of intracranial aneurysms originating from peripheral segments, which are comparable to prior established conventional FDS with acceptably low complication rates. However, alteration of a hemodynamic equilibrium in distal localizations requires special attention to prevent ischemic events.
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http://dx.doi.org/10.3389/fneur.2021.671915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8193674PMC
May 2021

Diffusion weighted imaging in high-grade gliomas: A histogram-based analysis of apparent diffusion coefficient profile.

PLoS One 2021 15;16(4):e0249878. Epub 2021 Apr 15.

Department for Radiology, University Hospital Halle (Saale), Halle (Saale), Germany.

Purpose: Glioblastoma and anaplastic astrocytoma represent the most commonly encountered high-grade-glioma (HGG) in adults. Although both neoplasms are very distinct entities in context of epidemiology, clinical course and prognosis, their appearance in conventional magnetic resonance imaging (MRI) is very similar. In search for additional information aiding the distinction of potentially confusable neoplasms, histogram analysis of apparent diffusion coefficient (ADC) maps recently proved to be auxiliary in a number of entities. Therefore, our present exploratory retrospective study investigated whether ADC histogram profile parameters differ significantly between anaplastic astrocytoma and glioblastoma, reflect the proliferation index Ki-67, or are associated with the prognostic relevant MGMT (methylguanine-DNA methyl-transferase) promotor methylation status.

Methods: Pre-surgical ADC volumes of 56 HGG patients were analyzed by histogram-profiling. Association between extracted histogram parameters and neuropathology including WHO-grade, Ki-67 expression and MGMT promotor methylation status was investigated due to comparative and correlative statistics.

Results: Grade IV gliomas were more heterogeneous than grade III tumors. More specifically, ADCmin and the lowest percentile ADCp10 were significantly lower, whereas ADCmax, ADC standard deviation and Skewness were significantly higher in the glioblastoma group. ADCmin, ADCmax, ADC standard deviation, Kurtosis and Entropy of ADC histogram were significantly correlated with Ki-67 expression. No significant difference could be revealed by comparison of ADC histogram parameters between MGMT promotor methylated and unmethylated HGG.

Conclusions: ADC histogram parameters differ significantly between glioblastoma and anaplastic astrocytoma and show distinct associations with the proliferative activity in both HGG. Our results suggest ADC histogram profiling as promising biomarker for differentiation of both, however, further studies with prospective multicenter design are wanted to confirm and further elaborate this hypothesis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249878PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049265PMC
April 2021

PET/MRI Delivers Multimodal Brain Signature in Alzheimer's Disease with De Novo PSEN1 Mutation.

Curr Alzheimer Res 2021 ;18(2):178-184

Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany.

Background: Little is known so far about the brain phenotype and the spatial interplay of different Alzheimer's disease (AD) biomarkers with structural and functional brain connectivity in the early phase of autosomal-dominant AD (ADAD). Multimodal PET/MRI might be suitable to fill this gap.

Material And Methods: We presented a 31-year-old male patient without a family history of dementia with progressive worsening of memory and motor function. Two separate sessions of 3T PET/MRI acquisitions were arranged with the ß-amyloid tracer [F]Florbetaben and the secondgeneration tau tracer [F]PI-2620. Simultaneously acquired MRI consisted of high-resolution 3D T1, diffusion-tensor imaging (DTI), and resting-state fMRI. PET/MRI data were compared with ten age-matched healthy controls.

Results: Widespread β-amyloid depositions were found in cortical regions, and striatum (Thal stage III) along with tau pathology restricted to the mesial-temporal structures (Braak stage III/IV). Volumetric/shape analysis of subcortical structures revealed atrophy of the hippocampal-amygdala complex. In addition, cortical thinning was detected in the right middle temporal pole. Alterations of multiple DTI indices were noted in the major white matter fiber bundles, together with disruption of default mode and sensory-motor network functional connectivity. Molecular genetic analysis by next-generation sequencing revealed a heterozygote missense pathogenic variant of the PSEN1 (Met233Val).

Conclusion: Multimodal PET/MR imaging is able to deliver, in a one-stop-shop approach, an array of molecular, structural and functional brain information in AD due to de novo pathogenic variant, which can be studied for spatial interplay and might provide a rationale for initiating anti- amyloid/tau therapeutic approaches.
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http://dx.doi.org/10.2174/1567205018666210414111536DOI Listing
January 2021

Hippocampal gray matter volume in the long-term course after transient global amnesia.

Neuroimage Clin 2021 12;30:102586. Epub 2021 Feb 12.

Department of Neurology (M.P., C.H., C.M.W., A.S., J.C., D.S.), Department of Neuroradiology (S.S., K.T.H.) and Department of Cognitive Neurology (A.T.O.), University of Leipzig Medical Center, Leipzig, Germany, German Center for Neurodegenerative Diseases, Dresden (A.G.), Germany. Electronic address:

Objective: In this retrospective, cross-sectional study we aimed to examine long-term memory deficits and gray matter volumes (GMV) in the hippocampus after transient global amnesia (TGA).

Methods: 20 patients with a history of TGA (TGA+, mean 6.5 years after TGA) and 20 age-matched healthy controls (TGA-) underwent neurocognitive assessment (i.e. Mini-Mental State Examination (MMSE), visuospatial, verbal and episodic autobiographical memory and visuospatial learning/navigation ["human water maze"]) in combination with structural cerebral MRI. Voxel-based morphometry (VBM) was used to detect GMV in the hippocampus in TGA+ versus TGA-.

Results: Besides slight differences in MMSE and visuo-spatial learning/navigation measured with a human water maze in TGA+ vs. TGA-, no other tests of visuo-spatial, verbal and autobiographical long-term memory differed between groups. VBM analyses yielded a statistically significant difference in bilateral hippocampal GMV with TGA+ compared to TGA- showing greater GMV in a region corresponding to bilateral CA1. However, none of the hippocampus-dependent cognitive measures correlated with hippocampal GMV.

Conclusion: In the long-term course after TGA, only subtle neurocognitive deficits without microstructural damage of the hippocampus could be detected. Greater GMV in bilateral hippocampus in TGA+ vs. TGA- may indicate that TGA triggers hippocampal GMV increase rather than atrophy.
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http://dx.doi.org/10.1016/j.nicl.2021.102586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7907892PMC
July 2021

Perifocal edema volume is not associated with immunohistochemical features reflecting proliferation potential, microvessel density, neoangiogenesis and invasiveness in brain metastasis.

Clin Neurol Neurosurg 2021 Mar 2;202:106537. Epub 2021 Feb 2.

Department of Diagnostic and Interventional Radiology, University of Magdeburg, Magdeburg, Germany.

Objective: Perifocal edema of brain tumors is associated with survival and neurological symptoms. Our aim was to analyze associations between perifocal edema and immunohistochemical features including proliferation potential, microvessel density, neoangiogenesis and invasiveness in brain metastasis (BM).

Methods: 35 patients with BM were included into the retrospective study. The tumors were localized supratentorial in 25 lesions (71.4%) and infratentorial in 10 lesions (28.6%). The following immunohistochemical features were calculated on histopathological specimens: microvessel density, proliferation index Ki 67, matrix-metallopeptidase 9 (MMP9) extracellular matrix metalloproteinase inducer (EMMPRIN) and vascular endothelial growth factor (VEGF) expression. Tumor and edema volumes were estimated semiautomatically on magnetic resonance images.

Results: There were no correlations between tumor volume and edema volume. Moreover, no correlation was identified between the investigated immunohistochemical features and tumor/edema volume. In the non-small cell lung cancer subgroup, a positive correlation between tumor volume and VEGF expression was observed (r = 0.52, P = 0.02) and edema volume correlated inversely with MMP9 expression (r = -0.53, P = 0.02).

Conclusion: In BM, no linear associations exist between tumor volumes, edema volumes and immunohistochemical features reflecting proliferation potential, neoangiogenesis, microvessel density and MMP9 expression. However, in the subgroup of non-small cell lung cancer, there might be associations between MMP9 expression and edema volume as well as between tumor volume and angiogenesis.
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http://dx.doi.org/10.1016/j.clineuro.2021.106537DOI Listing
March 2021

Association of Lesion Location and Depressive Symptoms Poststroke.

Stroke 2021 Mar 28;52(3):830-837. Epub 2021 Jan 28.

Department of Neurology, University of Leipzig Medical Center, Germany.

Background And Purpose: Poststroke depression is a common stroke sequel, yet its neurobiological substrates are still unclear. We sought to determine whether specific lesion locations are associated with depressive symptoms after stroke.

Methods: In a prospective study, 270 patients with first ever stroke were repeatedly tested with the depression subscale of the Hospital Anxiety and Depression Scale within the first 4 weeks and 6 months after stroke. Voxel-based lesion behavior mapping based on clinical imaging was performed to test for associations between symptoms of depression and lesion locations.

Results: Frequency of poststroke depression (Hospital Anxiety and Depression Scale-D score >7) after 6 months was 19.6%. Higher Hospital Anxiety and Depression Scale-D scores for depression within the first 4 weeks were the only independent predictor for poststroke depression after 6 months in a multiple logistic regression also including age, sex, lesion volume, stroke severity, Barthel-Index, and the anxiety subscale of the Hospital Anxiety and Depression Scale. Nonparametric permutation-test based voxel-based lesion behavior mapping identified a cluster of voxels mostly within the left ventrolateral prefrontal cortex where lesions were significantly associated with more depressive symptoms after 6 months. No such association was observed within the right hemisphere despite better lesion coverage.

Conclusions: Lesions in the left ventrolateral prefrontal cortex increase the risk of depressive symptoms 6 months poststroke. Lesions within the right hemisphere are unrelated to depressive symptoms. Recognition of left frontal lesions as a risk factor should help in the early diagnosis of poststroke depression through better risk stratification. The results are in line with evidence from functional imaging and noninvasive brain stimulation in patients without focal brain damage indicating that dysfunction in the left lateral prefrontal cortex contributes to depressive disorders.
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http://dx.doi.org/10.1161/STROKEAHA.120.031889DOI Listing
March 2021

Epidemiologic and anatomic aspects comparing incidental and ruptured intracranial aneurysms: A single centre experience.

J Clin Neurosci 2020 Nov 10;81:151-157. Epub 2020 Oct 10.

Department of Neurosurgery, University Hospital Leipzig, Liebigstrasse 20, 04103 Leipzig, Germany. Electronic address:

The feasibility of multicentric international data such as integrated in the PHASES score for patient counseling in unruptured intracranial aneurysms has recently been challenged. To determine, whether this data is applicable to local populations in a restricted catchment area, we performed a retrospective mono-centric analysis comparing patients with ruptured aneurysms to patients with incidental aneurysms. 200 patients with unruptured aneurysms and 197 patients after aneurysmal subarachnoid hemorrhage were analyzed for risk factors differing between the groups and to the general German population. Subgroup analysis was performed for 25 patients harboring multiple aneurysms, in 19 patients with intracavernous aneurysms and in 77 women of childbearing potential. While the preponderance of female patients was confirmed, significantly more men figured in the patient group with subarachnoid hemorrhage (36.4%) than among unruptured aneurysms (25%). Patients with bleeding events were significantly younger (51.6 years) than patients with incidental aneurysms (57.8 years). The rupture risk prediction of the PHASES score concerning aneurysm size below 7 mm and patient age over 70 years could not be confirmed, instead score points correlated to the clinical outcome after rupture. In our population, pregnant women were not overrepresented. Intracavernous carotid aneurysms contributed to the low risk profile of giant aneurysms. Thus, recommendations from pooled international data have to be adapted cautiously to local circumstances. We retained seven items with predictive value for outpatient counseling: age, smoking, hypertonus and concurrent vascular aberrations as patient characteristics and irregular shape, (increasing) largest diameter and the harboring vessel for the aneurysm.
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http://dx.doi.org/10.1016/j.jocn.2020.09.048DOI Listing
November 2020

Accuracy and reproducibility of automated white matter hyperintensities segmentation with lesion segmentation tool: A European multi-site 3T study.

Magn Reson Imaging 2021 02 19;76:108-115. Epub 2020 Nov 19.

IRCCS SDN, Naples, Italy.

Brain vascular damage accumulate in aging and often manifest as white matter hyperintensities (WMHs) on MRI. Despite increased interest in automated methods to segment WMHs, a gold standard has not been achieved and their longitudinal reproducibility has been poorly investigated. The aim of present work is to evaluate accuracy and reproducibility of two freely available segmentation algorithms. A harmonized MRI protocol was implemented in 3T-scanners across 13 European sites, each scanning five volunteers twice (test-retest) using 2D-FLAIR. Automated segmentation was performed using Lesion segmentation tool algorithms (LST): the Lesion growth algorithm (LGA) in SPM8 and 12 and the Lesion prediction algorithm (LPA). To assess reproducibility, we applied the LST longitudinal pipeline to the LGA and LPA outputs for both the test and retest scans. We evaluated volumetric and spatial accuracy comparing LGA and LPA with manual tracing, and for reproducibility the test versus retest. Median volume difference between automated WMH and manual segmentations (mL) was -0.22[IQR = 0.50] for LGA-SPM8, -0.12[0.57] for LGA-SPM12, -0.09[0.53] for LPA, while the spatial accuracy (Dice Coefficient) was 0.29[0.31], 0.33[0.26] and 0.41[0.23], respectively. The reproducibility analysis showed a median reproducibility error of 20%[IQR = 41] for LGA-SPM8, 14% [31] for LGA-SPM12 and 10% [27] with the LPA cross-sectional pipeline. Applying the LST longitudinal pipeline, the reproducibility errors were considerably reduced (LGA: 0%[IQR = 0], p < 0.001; LPA: 0% [3], p < 0.001) compared to those derived using the cross-sectional algorithms. The DC using the longitudinal pipeline was excellent (median = 1) for LGA [IQR = 0] and LPA [0.02]. LST algorithms showed moderate accuracy and good reproducibility. Therefore, it can be used as a reliable cross-sectional and longitudinal tool in multi-site studies.
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http://dx.doi.org/10.1016/j.mri.2020.11.008DOI Listing
February 2021

Loeffler's Endocarditis: An Integrated Multimodality Approach.

J Am Soc Echocardiogr 2020 12 29;33(12):1427-1441. Epub 2020 Oct 29.

Division of Cardiology, Department of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy.

Loeffler's endocarditis (LE) is the cardiac manifestation of hypereosinophilic syndrome, a rare systemic disease characterized by the sustained production of eosinophils leading to organ damage. Few data, principally by case reports, are available regarding the diagnostic workup in patients with suspected LE. Thus, we have performed a systematic search of the literature dealing with imaging in LE and propose an integrated multimodality imaging approach in the cardiac diagnostics of LE patients. The aim is to provide an updated state-of-the-art review focused on noninvasive and invasive imaging modalities for this rare and underdiagnosed disease. Standard and advanced echocardiography are typically the first cardiac imaging examinations when LE is suspected and they are also used later in follow-up for prognostic stratification and assessing response to treatment. Cardiac magnetic resonance provides a more detailed anatomical and functional evaluation of cardiac chambers, tissue characterization for the presence and extension of myocardial edema and fibrosis, and ventricular thrombi identification. Computed tomography scan and [18F]-fluoro-deoxy-glucose positron emission tomography may be helpful in selected cases to evaluate the cardiac involvement of LE as well as the other noncardiac manifestations of hypereosinophilic syndrome. Endomyocardial biopsy may be considered in patients with high clinical suspicion of LE if noninvasive imaging findings are confusing or not conclusive. The appropriate use of invasive and noninvasive imaging modalities, combining the available techniques with the patients' clinical features, will hopefully lead to early diagnosis, more accurate staging of disease, and timely treatment of LE that may prevent the irreversible myocardial damage of LE and adverse cardiovascular events.
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http://dx.doi.org/10.1016/j.echo.2020.09.002DOI Listing
December 2020

CSF Surfactant Protein Changes in Preterm Infants After Intraventricular Hemorrhage.

Front Pediatr 2020 25;8:572851. Epub 2020 Sep 25.

Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany.

Surfactant proteins (SP) have been shown to be inherent proteins of the human CNS and are altered during acute and chronic disturbances of CSF circulation. Aim of the study was to examine the changes of surfactant protein concentrations in CSF of preterm babies suffering from intraventricular hemorrhage. Consecutive CSF samples of 21 preterm infants with intraventricular hemorrhages (IVH) and posthemorrhagic hydrocephalus (PHHC) were collected at primary intervention, after 5-10 days and at time of shunt insertion ~50 days after hemorrhage. Samples were analyzed for surfactant proteins A, B, C, and G by ELISA assays and the results were compared to 35 hydrocephalus patients (HC) without hemorrhage and 6 newborn control patients. Premature patients with IVH showed a significant elevation of surfactant proteins SP-A, C, and G compared to HC and control groups: mean values for the respective groups were SP-A 4.19 vs. 1.08 vs. 0.38 ng/ml. Mean SP-C 3.63 vs. 1.47 vs. 0.48 ng/ml. Mean SP-G 3.86 vs. 0.17 vs. 0.2 ng/ml. SP-A and G concentrations were slowly falling over time without reaching normal values. SP-C levels declined faster following neurosurgical interventions and reached levels comparable to those of hydrocephalus patients without hemorrhage. Intraventricular hemorrhages of premature infants cause posthemorrhagic CSF flow disturbance and are associated with highly significant elevations of surfactant proteins A, C, and G independent of total CSF protein concentrations.
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http://dx.doi.org/10.3389/fped.2020.572851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7546901PMC
September 2020

Single-Center Experience With the Bare p48MW Low-Profile Flow Diverter and Its Hydrophilically Covered Version for Treatment of Bifurcation Aneurysms in Distal Segments of the Anterior and Posterior Circulation.

Front Neurol 2020 23;11:1050. Epub 2020 Sep 23.

Abteilung für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany.

Flow diversion has profoundly changed the way aneurysms are treated. However, it conventionally requires dual antiplatelet medication and has yet been considered off-label use in the posterior circulation or within peripheral vessels of the anterior circulation. Here, we report our experience with the p48MW/p48MW hydrophilic coating (HPC) in the anterior and posterior circulation. This novel low-profile flow diverter is specifically designed for treatment of small peripheral vessels, and the p48MW HPC has an anti-thrombotic polymer coating, which allows application of a single antiplatelet function medication in conditions that expectably require further surgery. Thirty-two patients were prospectively included. Twenty-six treatments were performed with one flow diverter, four required two overlapping flow diverters, one case demanded three overlapping flow diverters, and in one case, extensive dissecting aneurysm telescoping with eight flow diverters was necessary. Twenty-two complex bifurcation aneurysms were treated. Three months' follow-up was available for 14 patients. Deployment was uneventful in all cases. In four cases, undersizing was unavoidable and resulted in significant shortening of the flow diverter, which demanded implantation of further flow diverters to sufficiently treat the target aneurysm. Three flow diverters required balloon angioplasty for optimal wall approximation. All parent vessels remained patent. Available 3-month follow-up studies showed decreased influx or delayed washout in all aneurysms; none was occluded completely. There were no device-related clinical complications. Implantation of the p48MW/p48MW HPC is safe and effective for treatment of distally located cerebral aneurysms. Considering the reported rates of ischemic complications associated with flow diversion of complex bifurcation aneurysms, the p48MW/p48MW HPC potentially provides increased safety for complex bifurcation aneurysms in the anterior and posterior circulation.
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http://dx.doi.org/10.3389/fneur.2020.01050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7538783PMC
September 2020

Diagnostic benefit of high b-value computed diffusion-weighted imaging in acute brainstem infarction.

J Neuroradiol 2020 Sep 25. Epub 2020 Sep 25.

Department of Diagnostic and Interventional Radiology, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.

Background And Purpose: Diffusion-weighted imaging (DWI) is a cornerstone in diagnostic of ischemic stroke. The aim of this study was to investigate the usefulness of high-b-value computed DWI (c-DWI) in comparison to standard DWI in patients with acute brainstem infarction.

Materials And Methods: 56 patients with acute brainstem infarction were retrospectively analysed by two readers. DWI was obtained with the b-values 0, 500 and 1000 s/mm² on either a 1.5 or 3 T magnetic resonance imaging (MRI) scanner. c-DWI was calculated with a monoexponential model with high b-values 2000, 3000, 4000 and 5000 s/mm². All c-DWI series with high-b-values were compared to the standard DWI sequence at b-value of 1000 s/mm² in terms of image artifacts, lesion extent and contrast.

Results: There was no statistically significant difference between 1.5 and 3 T MRI regarding the measured ischemic lesion size. There were no statistically significant differences between the ischemic lesion sizes on DWI at b-values of 1000 s/mm² and on c-DWI at higher b-values. Overall, the contrast between the lesion and the surrounding normal areas improved with increasing b-value on the isotropic DWIs: maximum at b = 5000, followed by that at b 2000 and b 1000 s/mm², in order. The best relation between artifacts and lesion contrast was identified for b 2000 s/mm².

Conclusion: High b-value DWI derived from c-DWI has a higher visibility for ischemic brainstem lesions compared to standard DWI without additional time cost. The b-2000 image is recommended to use in clinical routine, higher b-value images lead to more imaging artifacts, which might result in misdiagnosis.
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http://dx.doi.org/10.1016/j.neurad.2020.09.004DOI Listing
September 2020

Individual differences in anxiety and automatic amygdala response to fearful faces: A replication and extension of Etkin et al. (2004).

Neuroimage Clin 2020 18;28:102441. Epub 2020 Sep 18.

Department of Psychosomatic Medicine and Psychotherapy, University of Leipzig, 04103 Leipzig, Germany. Electronic address:

Trait anxiety refers to the stable tendency to attend to threats and experience fears and worries across many situations. According to the widely noticed, pioneering investigation by Etkin et al. (2004) trait anxiety is strongly associated with reactivity in the right basolateral amygdala to non-conscious threat. Although this observation was based on a sample of only 17 individuals, no replication effort has been reported yet. We reexamined automatic amygdala responsiveness as a function of anxiety in a large sample of 107 participants. Besides self-report instruments, we administered an indirect test to assess implicit anxiety. To assess early, automatic stages of emotion processing, we used a color-decision paradigm presenting brief (33 ms) and backward-masked fearful facial expressions. N = 56 participants were unaware of the presence of masked faces. In this subset of unaware participants, the relationship between trait anxiety and basolateral amygdala activation by fearful faces was successfully replicated in region of interest analyses. Additionally, a relation of implicit anxiety with masked fear processing in the amygdala and temporal gyrus was observed. We provide evidence that implicit measures of affect can be valuable predictors of automatic brain responsiveness and may represent useful additions to explicit measures. Our findings support a central role of amygdala reactivity to non-consciously perceived threat in understanding and predicting dispositional anxiety, i.e. the frequency of spontaneously occurring anxiety in everyday life.
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http://dx.doi.org/10.1016/j.nicl.2020.102441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7522800PMC
June 2021

Changes of central noradrenaline transporter availability in immunotherapy-naïve multiple sclerosis patients.

Sci Rep 2020 09 4;10(1):14651. Epub 2020 Sep 4.

Department of Neurology, University of Leipzig, Leipzig, Germany.

The neurotransmitter noradrenaline (NA) mediates arousal, attention and mood, and exerts anti-inflammatory and neuroprotective effects. Alterations of monoamine signalling were reported in multiple sclerosis (MS) and psychiatric illness and may account for the high prevalence of comorbid depression and fatigue in MS patients. We assessed central noradrenaline transporter (NAT) availability using positron emission tomography (PET) and the NAT selective radiotracer S,S-[C]O-methylreboxetine in immunotherapy-naïve patients with relapsing-remitting MS (RRMS; n = 11) compared to healthy controls (HC; n = 12), and its association to lesion load, time since manifestation, the expanded disability status scale (EDSS), the fatigue scale Würzburger Erschöpfungsinventar bei MS (WEIMuS) and Beck Depression Inventory (BDI). We found NAT availability to be increased in the thalamus, amygdala, putamen and pons/midbrain of MS patients. No relation to clinical or psychometric variables was found. These first data indicate higher NAT availability in subcortical brain regions of immunotherapy-naïve RRMS patients. If these changes of noradrenergic neurotransmission predispose to psychiatric symptoms or associate with disease activity needs to be investigated in longitudinal studies or a larger sample which allows subgroup analyses.
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http://dx.doi.org/10.1038/s41598-020-70732-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7474089PMC
September 2020

Generalization of deep learning models for ultra-low-count amyloid PET/MRI using transfer learning.

Eur J Nucl Med Mol Imaging 2020 12 13;47(13):2998-3007. Epub 2020 Jun 13.

Department of Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany.

Purpose: We aimed to evaluate the performance of deep learning-based generalization of ultra-low-count amyloid PET/MRI enhancement when applied to studies acquired with different scanning hardware and protocols.

Methods: Eighty simultaneous [F]florbetaben PET/MRI studies were acquired, split equally between two sites (site 1: Signa PET/MRI, GE Healthcare, 39 participants, 67 ± 8 years, 23 females; site 2: mMR, Siemens Healthineers, 64 ± 11 years, 23 females) with different MRI protocols. Twenty minutes of list-mode PET data (90-110 min post-injection) were reconstructed as ground-truth. Ultra-low-count data obtained from undersampling by a factor of 100 (site 1) or the first minute of PET acquisition (site 2) were reconstructed for ultra-low-dose/ultra-short-time (1% dose and 5% time, respectively) PET images. A deep convolution neural network was pre-trained with site 1 data and either (A) directly applied or (B) trained further on site 2 data using transfer learning. Networks were also trained from scratch based on (C) site 2 data or (D) all data. Certified physicians determined amyloid uptake (+/-) status for accuracy and scored the image quality. The peak signal-to-noise ratio, structural similarity, and root-mean-squared error were calculated between images and their ground-truth counterparts. Mean regional standardized uptake value ratios (SUVR, reference region: cerebellar cortex) from 37 successful site 2 FreeSurfer segmentations were analyzed.

Results: All network-synthesized images had reduced noise than their ultra-low-count reconstructions. Quantitatively, image metrics improved the most using method B, where SUVRs had the least variability from the ground-truth and the highest effect size to differentiate between positive and negative images. Method A images had lower accuracy and image quality than other methods; images synthesized from methods B-D scored similarly or better than the ground-truth images.

Conclusions: Deep learning can successfully produce diagnostic amyloid PET images from short frame reconstructions. Data bias should be considered when applying pre-trained deep ultra-low-count amyloid PET/MRI networks for generalization.
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http://dx.doi.org/10.1007/s00259-020-04897-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7680289PMC
December 2020

[40-year-old woman with headache of unknown origin].

Dtsch Med Wochenschr 2020 06 3;145(11):781-782. Epub 2020 Jun 3.

Universitätsklinikum Leipzig, Abteilung für Neuroradiologie.

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http://dx.doi.org/10.1055/a-1113-1061DOI Listing
June 2020

Clinical suspicion of spondylodiscitis with equivocal MRI findings: does diffusion-weighted imaging prove helpful here?

Acta Radiol 2021 Mar 29;62(3):394-400. Epub 2020 May 29.

Department for Nuclear Medicine, University Hospital Leipzig, Leipzig, Germany.

Background: Despite the high sensitivity of magnetic resonance imaging (MRI), early detection of spondylodiscitis (SpD) remains challenging due to its low specificity.

Purpose: To assess the diagnostic value of diffusion-weighted imaging (DWI) in suspected cases of SpD with ambiguous early MRI findings in the differentiation of degenerative disorders (DD).

Material And Methods: In this prospective study, 52 patients suspected of having SpD underwent a whole-spine 3-T MRI scan comprising sagittal DWI. Of 58 conspicuous, T2-weighted, signal increased discs, 39 were successfully evaluated using DWI. Apparent diffusion coefficient (ADC) values and ADC maps were blindly analyzed using the region of interest of the conspicuous disc and a normal adjacent reference disc. Intraindividual ratios (conspicuous disc: reference disc) were calculated.

Results: All conspicuous discs showed increased absolute ADC values, which did not differ significantly between SpD (n = 22) and DD (n = 17). However, ADC ratio was significantly higher in SpD vs. DD ( < 0.05). In receiver operating characteristic curve analysis, an ADC ratio threshold of 1.6 resulted in 45% sensitivity and 88% specificity (area under the curve = 0.69) for SpD diagnosis.

Conclusion: The absolute ADC value does not provide a reliable diagnosis of SpD. Increased diffusivity can be an indication of infection but should always be discussed in the context of existing disc degeneration.
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http://dx.doi.org/10.1177/0284185120927905DOI Listing
March 2021

Amygdalar nuclei and hippocampal subfields on MRI: Test-retest reliability of automated volumetry across different MRI sites and vendors.

Neuroimage 2020 09 13;218:116932. Epub 2020 May 13.

CRMBM-CEMEREM, UMR 7339, Aix-Marseille University, CNRS, Marseille, France.

Background: The amygdala and the hippocampus are two limbic structures that play a critical role in cognition and behavior, however their manual segmentation and that of their smaller nuclei/subfields in multicenter datasets is time consuming and difficult due to the low contrast of standard MRI. Here, we assessed the reliability of the automated segmentation of amygdalar nuclei and hippocampal subfields across sites and vendors using FreeSurfer in two independent cohorts of older and younger healthy adults.

Methods: Sixty-five healthy older (cohort 1) and 68 younger subjects (cohort 2), from the PharmaCog and CoRR consortia, underwent repeated 3D-T1 MRI (interval 1-90 days). Segmentation was performed using FreeSurfer v6.0. Reliability was assessed using volume reproducibility error (ε) and spatial overlapping coefficient (DICE) between test and retest session.

Results: Significant MRI site and vendor effects (p ​< ​.05) were found in a few subfields/nuclei for the ε, while extensive effects were found for the DICE score of most subfields/nuclei. Reliability was strongly influenced by volume, as ε correlated negatively and DICE correlated positively with volume size of structures (absolute value of Spearman's r correlations >0.43, p ​< ​1.39E-36). In particular, volumes larger than 200 ​mm (for amygdalar nuclei) and 300 ​mm (for hippocampal subfields, except for molecular layer) had the best test-retest reproducibility (ε ​< ​5% and DICE ​> ​0.80).

Conclusion: Our results support the use of volumetric measures of larger amygdalar nuclei and hippocampal subfields in multisite MRI studies. These measures could be useful for disease tracking and assessment of efficacy in drug trials.
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http://dx.doi.org/10.1016/j.neuroimage.2020.116932DOI Listing
September 2020

Tumor-to-Tumor Metastasis of Multiple Meningiomas and Clear Cell Renal Cell Carcinoma Metastasis as First Clinical Appearance of Kidney Cancer: A Case Report and Analysis.

J Neurol Surg Rep 2020 Jan 31;81(1):e10-e14. Epub 2020 Mar 31.

Department of Neurosurgery, University Hospital Leipzig, Leipzig, Germany.

 Meningioma accounts for more than 35% of all diagnosed brain tumors of the central nervous system and, moreover, it is the most common benign recipient of tumor-to-tumor metastasis. Several cases with tumor-to-meningioma metastasis by breast, lung, and intestinal cancer have been described before.  The case of a patient with a longstanding history of multiple meningiomas (  = 4) that suddenly became symptomatic and progressive in size is presented. Following extirpation of the two largest meningiomas, a histological examination revealed two separate tumor-to-meningioma metastases of clear cell renal cell carcinoma that was undiagnosed before. Post-surgical computed tomography scan then confirmed tumor-suspect lesions in both kidneys. After recovery and rehabilitation, adjuvant radio-chemo-therapy was applied according to protocols for kidney cancer. No other tumor-to-tumor-suspect event occurred since then for the remaining two meningiomas.  Review of literature and our case strengthens the idea of meningioma as a favorable premetastatic niche. Considering that the patient lived with a stable disease for many years, a sudden progress of tumor size in association with neurological deterioration was highly suspected for malign involvement, including the possibility of tumor-to-tumor metastasis. Physicians should be aware about this phenomenon and treat patients accordingly to the underlying disease.
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http://dx.doi.org/10.1055/s-0040-1708846DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7108953PMC
January 2020

Flow diversion in challenging vascular anatomies: the use of low profile stent retrievers for safe and accurate positioning of the microcatheter.

CVIR Endovasc 2020 Mar 30;3(1):19. Epub 2020 Mar 30.

Department for Neuroradiology, University Hospital Leipzig, Liebigstraße 20, 04103, Leipzig, Germany.

Background: Hemodynamic therapy with Flow-Diverters has become a fundamental option for treatment of cerebral aneurysms. A major obstacle of Flow-Diverters is the comparatively stiff microcatheter required for implantation. Consequentially, maneuverability is limited and primary catheterization of peripheral targets may be difficult or even futile in challenging vascular anatomies. To overcome this, a highly navigable microcatheter must be used to attain the desired vascular segment, followed by a hardly controllable exchange-maneuver via a long microwire, involving a high risk for wire-perforation. Our study aimed to investigate the value of low-profile stent-retrievers as a railway for introduction of the required microcatheter, which allows to maintain a stable endovascular position and reduce the risk for procedural vessel injury.

Methods: 14cases (8females, mean-age 59y) of Flow-Diverter-Implantation requiring the use of a low-profile stent-retriever were reviewed. All cases featured a challenging vascular anatomy. After micro-catheterization of the desired segment, the stent-retriever was carefully deployed as an anchor in a secure, distal location. In all cases a pREset/LITE-stent-retriever was used for introduction of the equipment required for implantation.

Results: In all cases the anchoring-maneuver was performed without technical complications. The stent-retrievers maintained a stable position after deployment in all situations. No potential traumatic sudden movements of the microcatheter occurred. No procedure-related perforations, dissections or vasospasms were observable during the interventions or their aftermath.

Conclusions: In our experience the stent-retriever-anchoring-maneuver represents a potentially essential and safe amendment for flow diverter treatment in technically challenging situations.
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http://dx.doi.org/10.1186/s42155-020-00106-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7103572PMC
March 2020

Incidental findings on CT angiography of the head and neck in stroke patients. Evaluation of frequency and detection rate.

Clin Neurol Neurosurg 2020 06 20;193:105783. Epub 2020 Mar 20.

Department of Diagnostic and Interventional Radiology, University of Magdeburg, Magdeburg, Leipziger Str 44, 39120 Magdeburg, Germany. Electronic address:

Objective: A comprehensive CT algorithm in suspected ischemic stroke consists of a native CT scan, CT perfusion imaging of the brain and a CT angiography from the aortic arch to the vertex. Besides core findings of the brain and targeted vessels, various other findings may be identified. We analyzed a large patient sample and estimated the frequency of incidental findings (IFs) and whether these findings were correctly mentioned in the radiological reports.

Patients And Methods: In the time period between 01/16 and 02/19 the radiological database of one hospital containing 1625 patients admitted for stroke suspicion were retrospectively evaluated. In total 1175 patients with ischemic stroke CTs were included. IFs were classified according to Lumbreras et al. for their clinical relevance. The primary radiological report was used to classify, whether the finding was reported initially or not.

Results: Overall, 1988 IFs were identified in 1175 patients (mean 1.7 findings per patient). The most frequent finding were thyroid incidentalomas with n = 461 (23.2 % of all findings), followed by signs of mucosal swelling and/or opacification of the nasal sinus (n = 391, 19.7 %). Regarding clinical relevance, 181 findings were of major relevance (9.1 % of all findings), 902 were of moderate relevance (45.4 %) and 905 were of minor relevance (45.5 %). Overall, 772 findings (38.8 %) were not reported and 1216 (61.2 %) were sufficiently reported by the radiologist.

Conclusion: The present study corroborates that incidental findings are frequent in patients undergoing ischemic stroke CT, which are about half of moderate and major relevance. About 40 % of these findings were not mentioned in the primary radiology report, including findings of high clinical relevance. The radiologist should be aware of these findings.
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http://dx.doi.org/10.1016/j.clineuro.2020.105783DOI Listing
June 2020

Tractography in Neurosurgery: A Systematic Review of Current Applications.

J Neurol Surg A Cent Eur Neurosurg 2020 Sep 16;81(5):442-455. Epub 2020 Mar 16.

Department of Neurosurgery, University Hospital Leipzig, Leipzig, Germany.

The ability to visualize the brain's fiber connections noninvasively in vivo is relatively young compared with other possibilities of functional magnetic resonance imaging. Although many studies showed tractography to be of promising value for neurosurgical care, the implications remain inconclusive. An overview of current applications is presented in this systematic review. A search was conducted for (("tractography" or "fiber tracking" or "fibre tracking") and "neurosurgery") that produced 751 results. We identified 260 relevant articles and added 20 more from other sources. Most publications concerned surgical planning for resection of tumors ( = 193) and vascular lesions ( = 15). Preoperative use of transcranial magnetic stimulation was discussed in 22 of these articles. Tractography in skull base surgery presents a special challenge ( = 29). Fewer publications evaluated traumatic brain injury (TBI) ( = 25) and spontaneous intracranial bleeding ( = 22). Twenty-three articles focused on tractography in pediatric neurosurgery. Most authors found tractography to be a valuable addition in neurosurgical care. The accuracy of the technique has increased over time. There are articles suggesting that tractography improves patient outcome after tumor resection. However, no reliable biomarkers have yet been described. The better rehabilitation potential after TBI and spontaneous intracranial bleeding compared with brain tumors offers an insight into the process of neurorehabilitation. Tractography and diffusion measurements in some studies showed a correlation with patient outcome that might help uncover the neuroanatomical principles of rehabilitation itself. Alternative corticofugal and cortico-cortical networks have been implicated in motor recovery after ischemic stroke, suggesting more complex mechanisms in neurorehabilitation that go beyond current models. Hence tractography may potentially be able to predict clinical deficits and rehabilitation potential, as well as finding possible explanations for neurologic disorders in retrospect. However, large variations of the results indicate a lack of data to establish robust diagnostical concepts at this point. Therefore, in vivo tractography should still be interpreted with caution and by experienced surgeons.
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http://dx.doi.org/10.1055/s-0039-1691823DOI Listing
September 2020

Histogram Analysis of Diffusion Weighted Imaging in Low-Grade Gliomas: Characterization of Tumor Architecture and Corresponding Neuropathology.

Front Oncol 2020 25;10:206. Epub 2020 Feb 25.

Department for Neuroradiology, University Hospital Leipzig, Leipzig, Germany.

Low-grade gliomas (LGG) in adults are usually slow growing and frequently asymptomatic brain tumors, originating from glial cells of the central nervous system (CNS). Although regarded formally as "benign" neoplasms, they harbor the potential of malignant transformation associated with high morbidity and mortality. Their complex and unpredictable tumor biology requires a reliable and conclusive presurgical magnetic resonance imaging (MRI). A promising and emerging MRI approach in this context is histogram based apparent diffusion coefficient (ADC) profiling, which recently proofed to be capable of providing prognostic relevant information in different tumor entities. Therefore, our study investigated whether histogram profiling of ADC distinguishes grade I from grade II glioma, reflects the proliferation index Ki-67, as well as the IDH (isocitrate dehydrogenase) mutation and MGMT (methylguanine-DNA methyl-transferase) promotor methylation status. Pre-treatment ADC volumes of 26 LGG patients were used for histogram-profiling. WHO-grade, Ki-67 expression, IDH mutation, and MGMT promotor methylation status were evaluated. Comparative and correlative statistics investigating the association between histogram-profiling and neuropathology were performed. Almost the entire ADC profile (p25, p75, p90, mean, median) was significantly lower in grade II vs. grade I gliomas. Entropy, as second order histogram parameter of ADC volumes, was significantly higher in grade II gliomas compared with grade I gliomas. Mean, maximum value (ADCmax) and the percentiles p10, p75, and p90 of ADC histogram were significantly correlated with Ki-67 expression. Furthermore, minimum ADC value (ADCmin) was significantly associated with MGMT promotor methylation status as well as ADC entropy with IDH-1 mutation status. ADC histogram-profiling is a valuable radiomic approach, which helps differentiating tumor grade, estimating growth kinetics and probably prognostic relevant genetic as well as epigenetic alterations in LGG.
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http://dx.doi.org/10.3389/fonc.2020.00206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7051987PMC
February 2020

How tissue fluidity influences brain tumor progression.

Proc Natl Acad Sci U S A 2020 01 16;117(1):128-134. Epub 2019 Dec 16.

Department of Radiology, Charité - Universitätsmedizin Berlin, 10117 Berlin, Germany;

Mechanical properties of biological tissues and, above all, their solid or fluid behavior influence the spread of malignant tumors. While it is known that solid tumors tend to have higher mechanical rigidity, allowing them to aggressively invade and spread in solid surrounding healthy tissue, it is unknown how softer tumors can grow within a more rigid environment such as the brain. Here, we use in vivo magnetic resonance elastography (MRE) to elucidate the role of anomalous fluidity for the invasive growth of soft brain tumors, showing that aggressive glioblastomas (GBMs) have higher water content while behaving like solids. Conversely, our data show that benign meningiomas (MENs), which contain less water than brain tissue, are characterized by fluid-like behavior. The fact that the 2 tumor entities do not differ in their soft properties suggests that fluidity plays an important role for a tumor's aggressiveness and infiltrative potential. Using tissue-mimicking phantoms, we show that the anomalous fluidity of neurotumors physically enables GBMs to penetrate surrounding tissue, a phenomenon similar to Saffman-Taylor viscous-fingering instabilities, which occur at moving interfaces between fluids of different viscosity. Thus, targeting tissue fluidity of malignant tumors might open horizons for the diagnosis and treatment of cancer.
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http://dx.doi.org/10.1073/pnas.1913511116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6955323PMC
January 2020

Radiomics Model Based on Non-Contrast CT Shows No Predictive Power for Complete Pathological Response in Locally Advanced Rectal Cancer.

Cancers (Basel) 2019 Oct 29;11(11). Epub 2019 Oct 29.

Department of Diagnostic and Interventional Radiology, University of Leipzig, 04103 Leipzig, Germany.

(1) Background: About 15% of the patients undergoing neoadjuvant chemoradiation for locally advanced rectal cancer exhibit pathological complete response (pCR). The surgical approach is associated with major risks as well as a potential negative impact on quality of life and has been questioned in the past. Still, there is no evidence of a reliable clinical or radiological surrogate marker for pCR. This study aims to replicate previously reported response predictions on the basis of non-contrast CT scans on an independent patient cohort. (2) Methods: A total of 169 consecutive patients (126 males, 43 females) that underwent neoadjuvant chemoradiation and consecutive total mesorectal excision were included. The solid tumors were segmented on CT scans acquired on the same scanner for treatment planning. To quantify intratumoral 3D spatial heterogeneity, 1819 radiomics parameters were derived per case. Feature selection and algorithmic modeling were performed to classify pCR vs. non-pCR cases. A random forest model was trained on the dataset using 4-fold cross-validation. (3) Results: The model achieved an accuracy of 87%, higher than previously reported. Correction for the imbalanced distribution of pCR and non-PCR cases (13% and 87% respectively) was applied, yielding a balanced accuracy score of 0.5%. An additional experiment to classify a computer-generated random data sample using the same model led to comparable results. (4) Conclusions: There is no evidence of added value of a radiomics model based on on-contrast CT scans for prediction of pCR in rectal cancer. The imbalance of the target variable could be identified as a key issue, leading to a biased model and optimistic predictions.
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http://dx.doi.org/10.3390/cancers11111680DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6895820PMC
October 2019

Delayed Stroke after Aneurysm Treatment with Flow Diverters in Small Cerebral Vessels: A Potentially Critical Complication Caused by Subacute Vasospasm.

J Clin Med 2019 Oct 10;8(10). Epub 2019 Oct 10.

Department of Neuroradiology, University Hospital Leipzig, 04103 Leipzig, Germany.

Flow diversion (FD) is a novel endovascular technique based on the profound alteration of cerebrovascular hemodynamics, which emerged as a promising minimally invasive therapy for intracranial aneurysms. However, delayed post-procedural stroke remains an unexplained concern. A consistent follow-up-regimen has not yet been defined, but is required urgently to clarify the underlying cause of delayed ischemia. In the last two years, 223 patients were treated with six different FD devices in our center. We identified subacute, FD-induced segmental vasospasm (SV) in 36 patients as a yet unknown, delayed-type reaction potentially compromising brain perfusion to a critical level. Furthermore, 86% of all patients revealed significant SV approximately four weeks after treatment. In addition, 56% had SV with 25% stenosis, and 80% had additional neointimal hyperplasia. Only 13% exhibited SV-related high-grade stenosis. One of those suffered stroke due to prolonged SV, requiring neurocritical care and repeated intra-arterial (i.a.) biochemical angioplasty for seven days to prevent territorial infarction. Five patients suffered newly manifested, transient hemicrania accompanying a compensatorily increased ipsilateral leptomeningeal perfusion. One treated vessel obliterated permanently. Hence, FD-induced SV is a frequent vascular reaction after FD treatment, potentially causing symptomatic ischemia or even stroke, approximately one month post procedure. A specifically early follow-up-strategy must be applied to identify patients at risk for ischemia, requiring intensified monitoring and potentially anti-vasospastic treatment.
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http://dx.doi.org/10.3390/jcm8101649DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832548PMC
October 2019

Comparison of machine learning classifiers for differentiation of grade 1 from higher gradings in meningioma: A multicenter radiomics study.

Magn Reson Imaging 2019 11 16;63:244-249. Epub 2019 Aug 16.

Department of Diagnostic and Interventional Radiology, University of Leip-zig, Leipzig, Germany.

Background And Purpose: Advanced imaging analysis for the prediction of tumor biology and modelling of clinically relevant parameters using computed imaging features is part of the emerging field of radiomics research. Here we test the hypothesis that a machine learning approach can distinguish grade 1 from higher gradings in meningioma patients using radiomics features derived from a heterogenous multicenter dataset of multi-paramedic MRI.

Methods: A total of 138 patients from 5 international centers that underwent MRI prior to surgical resection of intracranial meningiomas were included. Segmentation was performed manually on co-registered multi-parametric MR images using apparent diffusion coefficient (ADC) maps, T1-weighted (T1), post-contrast T1-weighted (T1c), subtraction maps (Sub, T1c - T1), T2-weighted fluid-attenuated inversion recovery (FLAIR) and T2-weighted (T2) images. Feature selection was performed and using cross-validation to separate training from testing data, four machine learning classifiers were scored on combinations of MRI modalities: random forest (RF), extreme gradient boosting (XGBoost), support vector machine (SVM) and multilayer perceptron (MLP).

Results: The best AUC of 0.97 (1.0 and 0.97 for sensitivity and specificity) was observed for the combination of ADC, ADC of the peritumoral edema, T1, T1c, Sub and FLAIR-derived features using only 16 of the 10,914 possible features and XGBoost.

Conclusions: Machine learning using radiomics features derived from multi-parametric MRI is capable of high AUC scores with high sensitivity and specificity in classifying meningiomas between low and higher gradings despite heterogeneous protocols across different centers. Feature selection can be performed effectively even when extracting a large amount of data for radiomics fingerprinting.
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http://dx.doi.org/10.1016/j.mri.2019.08.011DOI Listing
November 2019

[Spontaneous Pneumatosis - An Imprinting Finding].

Rofo 2019 Nov 25;191(11):975-977. Epub 2019 Jul 25.

BAG Dr. Richter & Dr. Stumpp, Practice for Radiology, Wurzen, Germany.

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http://dx.doi.org/10.1055/a-0893-6813DOI Listing
November 2019

Rheologically Essential Surfactant Proteins of the CSF Interacting with Periventricular White Matter Changes in Hydrocephalus Patients - Implications for CSF Dynamics and the Glymphatic System.

Mol Neurobiol 2019 Nov 24;56(11):7863-7871. Epub 2019 May 24.

Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany.

Surfactant proteins (SP) are multi-systemic proteins playing crucial roles in the regulation of rheological properties of physiological fluids, host defense, and the clearance of potentially harmful metabolites. Hydrocephalus patients suffer from disturbed central nervous system (CNS) fluid homeostasis and exhibit remarkably altered SP concentrations within the cerebrospinal fluid (CSF). A connection between CSF-SPs, CSF flow, and ventricular dilatation, a morphological hallmark of hydrocephalus, has been reported previously. However, currently there are no studies investigating the link between rheologically active SPs and periventricular white matter changes caused by impaired CSF microcirculation in hydrocephalic conditions. Thus, the aim of this study was to assess their possible relationships. The present study included 47 individuals (27 healthy subjects and 20 hydrocephalus patients). CSF specimens were analyzed for concentrations of SP-A, SP-C, and SP-D by using enzyme-linked immunosorbent assays (ELISAs). Axial T2w turbo inversion recovery magnitude (TIRM) magnetic resonance imaging was employed in all cases. Using a custom-made MATLAB-based tool for quantification of magnetic resonance signal intensities in the brain, parameters related to disturbed deep white matter CSF microcirculation were estimated (TIRM signal intensity (SI)-mean, minimum, maximum, median, mode, standard deviation, and percentiles, p10th, p25th, p75th, p90th, as well as kurtosis, skewness, and entropy of the SI distribution). Subsequently, statistical analysis was performed (IBM SPSS 24™) to identify differences between hydrocephalic patients and healthy individuals and to further investigate the connections between CSF-SP changes and deep white matter signal intensities. SP-A (0.38 ± 0.23 vs. 0.76 ± 0.49 ng/ml) and SP-C (0.54 ± 0.28 vs. 1.27 ± 1.09 ng/ml) differed between healthy controls and hydrocephalus patients in a statistically significant manner. Also, corresponding quantification of white matter signal intensities revealed statistically significant differences between hydrocephalus patients and healthy individuals: SImean (370.41 ± 188.15 vs. 222.27 ± 99.86, p = 0.001), SImax (1115.30 ± 700.12 vs. 617.00 ± 459.34, p = 0.005), SImedian (321.40 ± 153.17 vs. 209.52 ± 84.86, p = 0.001), SImode (276.55 ± 125.63 vs. 197.26 ± 78.51, p = 0.011), SIstd (157.09 ± 110.07 vs. 81.71 ± 64.94, p = 0.005), SIp10 (229.10 ± 104.22 vs. 140.00 ± 63.12, p = 0.001), SIp25 (266.95 ± 122.62 vs. 175.63 ± 71.42, p = 0.002), SIp75 (428.80 ± 226.88 vs. 252.19 ± 110.91, p = 0.001), SIp90 (596.47 ± 345.61 vs. 322.06 ± 176.00, p = 0.001), skewness (1.19 ± 0.68 vs. 0.43 ± 1.19, p = 0.014), and entropy (5.36 ± 0.37 vs. 4.92 ± 0.51, p = 0.002). There were no differences regarding SP-D levels in hydrocephalus patients vs. healthy controls. In the acute hydrocephalic subgroup, correlations were as follows: SP-A showed a statistically significant correlation with SImax (r = 0.670, p = 0.024), SIstd (r = 0.697, p = 0.017), SIp90 (r = 0.621, p = 0.041), and inverse correlation with entropy (r = - 0.700, p = 0.016). SP-C correlated inversely with entropy (r = - 0.686, p = 0.020). For the chronic hydrocephalus subgroup, the following correlations were identified: SP-A correlated with kurtosis of the TIRM histogram (r = - 0.746, p = 0.021). SP-C correlated with SImean (r = - 0.688, p = 0.041), SImax (r = - 0.741, p = 0.022), SImedian (r = - 0.716, p = 0.030), SImode (r = - 0.765, p = 0.016), SIstd (r = - 0.671, p = 0.048), SIp25 (r = - 0.740, p = 0.023), SIp75 (r = - 0.672, p = 0.048), and SIp90 (r = - 0.667, p = 0.050). SP-D apparently does not play a major role in CSF fluid physiology. SP-A and SP-C are involved in different aspects of CNS fluid physiology. SP-A appears to play an essential compensatory role in acute hydrocephalus and seems less involved in chronic hydrocephalus. In contrary, SP-C profile and white matter changes are remarkably connected in CSF of chronic hydrocephalus patients. Considering the association between CSF flow phenomena, white matter changes, and SP-C profiles, the latter may especially contribute to the regulation of paravascular glymphatic physiology.
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http://dx.doi.org/10.1007/s12035-019-01648-zDOI Listing
November 2019
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