Jan Menke

University of Kassel

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Wieland Staab

German Centre for Cardiovascular Research

Jan M Sohns

University of Göttingen

Joachim Lotz

German Centre for Cardiovascular Research

Christina Unterberg‐Buchwald

German Centre for Cardiovascular Research

Alexander Schwarz

Institute of Evolutionary Physiology and Biochemistry

Inga‐Marie Schaefer

Harvard University

Leonard Bergau

Universitätsmedizin Göttingen

Lars‐Christian Horn

University Hospital Leipzig

Christian Sohns

Heart and Diabetes Center North Rhine-Westphalia

Jan Henrik Ardenkjær‐Larsen

Technical University of Denmark

Cooperative Institutions

Universitätsmedizin Göttingen

University of Göttingen

Heidelberg University

University Medical Center

Charité - Universitätsmedizin Berlin

Klinik für Frauenheilkunde

University Hospital Heidelberg

Heinrich Heine University Düsseldorf

University Hospital Cologne

Nephrologisches Zentrum Goettingen

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Funktionelle MRT mit Negativen BOLD-Signalveränderungen im Primären Somatosensorischen Kortex unter Einluss des Alterns

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren (2013)

JM Sohns Sonja Gröschel Jürgen Baudewig Lena Becker Carsten Schmidt‐Samoa

Ziele: In addition to a contralateral activation of the primary and secondary somatosensory cortex, peripheral sensory stimulation has been shown to elicit responses in the ipsilateral primary somatosensory cortex (SI). In particular, evidence is accumulating that processes of interhemispheric inhibition as depicted by negative BOLD signal changes are part of somatosensory processes. The aim of the study was to analyze age-related differences in patterns of cerebral activation in the somatosensory system in general and processes of interhemispheric inhibition in particular. Methode: An fMRI study was performed including 14 younger (23.3 ± 0.9 years) and 13 healthy older participants (73.2 ± 8.3 years). All subjects were scanned during peripheral electrical median nerve stimulation (40 Hz) to obtain BOLD responses in the somatosensory system. Moreover, the individual perception threshold (CPT) as a quantitative measure of sensory function was determined in a separate psychophysical testing. Ergebnis: Significant increases in BOLD signal could be measured within the contralateral primary somatosensory cortex (SI), in the bilateral SII cortex, the contralateral insula, thalamus and Brodman area 6 as well as in the ipsilateral cerebellum in both groups. Whereas a large cluster of negative BOLD signal changes was observed in the ipsilateral SI of the young subjects, this cluster was considerably smaller in the group of old subjects. The psychophysical experiments yielded a significant age-dependent effect of CPT change with less difference in the older group which is in line with the significantly smaller alterations in maximal BOLD signal change in the contra- and ipsilateral SI cortex found between the 2 groups. Schlussfolgerung: Healthy aging seems to be associated with a decrease in intracerebral inhibition as reflected by smaller negative BOLD signal changes during fMRI tasks. This finding could constitute an important link between age-related neurophysiological changes and behavioral alterations in humans.

Secondary somatosensory cortex

Somatosensory evoked potential

Sensory cortex

10.1055/s-0033-1346639

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Prevalence and clinical significance of incidental extra-mammary findings in breast magnetic resonance imaging: A retrospective study of 1070 patients

Clinical Imaging (2017)

Wieland Staab Jan Menke Christian Sohns Susanne Wienbeck Lukas Bauer

Breast imaging

Clinical Significance

Breast MRI

10.1016/j.clinimag.2017.06.005

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Citations (4)

Cardiac CT in an aberrant right coronary artery

BMJ Case Reports (2015)

Jan Menke

An 18-year-old man experienced acute chest pain. Transthoracic echocardiography was normal. ECG showed anterior ST-depression and posterior ST-elevation, and the troponin-T test was positive. Therefore the differential diagnosis included a myocardial ischaemic event. Catheter angiography ruled out coronary artery disease but detected an anomalous origin of the right coronary artery at the upper left sinus of Valsalva. Contrast-enhanced cardiac CT was subsequently performed (figure 1), with panel A (plus video 1) showing an angulated transverse reformation and panel B (plus video 2) a coronal reformation. The …

10.1136/bcr-2014-208594

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Glioma infiltration of the corpus callosum: early signs detected by DTI

Journal of Neuro-Oncology (2013)

Kai Kallenberg Torsten Goldmann Jan Menke Herwig Strik Hans Bock

Abstract The most frequent primary brain tumors, anaplastic astrocytomas (AA) and glioblastomas (GBM): tend to invasion of the surrounding brain. Histopathological studies found malignant cells in macroscopically unsuspicious brain parenchyma remote from the primary tumor, even affecting the contralateral hemisphere. In early stages, diffuse interneural infiltration with changes of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) is suspected. The purpose of this study was to investigate the value of DTI as a possible instrument of depicting evidence of tumor invasion into the corpus callosum (CC). Preoperatively, 31 patients with high-grade brain tumors (8 AA and 23 GBM) were examined by MRI at 3 T, applying a high-resolution diffusion tensor imaging (DTI) sequence. ADC- and FA-values were analyzed in the tumor-associated area of the CC as identified by fiber tracking, and were compared to matched healthy controls. In (MR-)morphologically normal appearing CC the ADC values were elevated in the tumor patients ( n = 22; 0.978 × 10 −3 mm²/s) compared to matched controls (0.917 × 10 −3 mm²/s, p < 0.05), and the corresponding relative FA was reduced (rFA: 88 %, p < 0.01). The effect was pronounced in case of affection of the CC visible on MRI ( n = 9; 0.978 × 10 −3 mm²/s, p < 0.05; rFA: 72 %, p < 0.01). Changes in diffusivity and anisotropy in the CC can be interpreted as an indicator of tumor spread into the contralateral hemisphere not visible on conventional MRI.

Infiltration (HVAC)

Parenchyma

Brain tumor

10.1007/s11060-013-1049-y

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Citations (69)

Diagnostic accuracy and utility of coronary CT angiography with consideration of unevaluable results: A systematic review and multivariate Bayesian random-effects meta-analysis with intention to diagnose

European Radiology (2015)

Jan Menke Jörg Kowalski

Interventional radiology

10.1007/s00330-015-3831-z

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Citations (68)

Diagnostische Genauigkeit der kontrastmittelgestützten MR-Angiographie bei hochgradigen Karotisstenosen: Meta-Analyse mit Vergleich von verschiedenen Untersuchungstechniken

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren (2012)

Jan Menke

Ziele: Diese Meta-Analyse untersucht die Genauigkeit der kontrastmittelgestützten MR-Angiographie (MRA) für die Diagnostik von hochgradigen Karotisstenosen und Karotisverschlüssen. Methode: Drei Literaturdatenbanken inklusive PubMed wurden nach „carotid artery disease“ und ähnlichen Begriffen durchsucht. Eingeschlossen wurden Studien, die bei mindestens 20 Patienten mit vermuteter oder bekannter hochgradiger Karotisstenose (70–99% Lumenreduktion nach NASCET-Kriterien) oder Karotisverschluss die kontrastmittelgestützte MRA mit der Katheterangiographie verglichen hatten. Für die Meta-Analyse der Sensitivität und Spezifität wurde ein bivariates random-effects Modell verwendet. Zusätzlich wurde der Effekt verschiedener Untersuchungstechniken auf die diagnostische Genauigkeit mittels bivariater Meta-Regression untersucht. Ergebnis: Insgesamt wurden 17 Studien mit 1714 Karotiden von 905 Patienten eingeschlossen. Für die Diagnose von >70% Steno-Okklusionen (gemäß NASCET-Kriterien) war die durchschnittliche Sensitivität der Karotis-MRA 94,3% (95%-Konfidenzintervall: 92,0–96,0%) und die Spezifität war 93,0% (89,8–95,3%). In der Subgruppen-Analyse war die Spezifität höher, wenn nicht nur Maximum-Intensitäts-Projektionen (MIP-Bilder) sondern auch die dreidimensionalen Originalbilder verwendet wurden (P=0,01). Die Spezifität war ebenfalls höher, wenn die Befundung mit Monitorbildern anstelle von Hardcopies erfolgte (P=0.02). Die verschiedenen verwendeten Kontrastmittel-Timing-Techniken (Bolus-Timing, fluoroskopisches Triggern oder zeitaufgelöste Untersuchung) zeigten keine signifikanten Unterschiede bezüglich der diagnostischen Genauigkeit (P>0,05). Schlussfolgerung: Bei der Beurteilung von hochgradigen Karotisstenosen hat die kontrastmittelgestützte MRA eine hohe diagnostische Genauigkeit. Für eine möglichst hohe Spezifität sollten nicht nur MIP-Bilder sondern auch die dreidimensionalen Originalbilder verwendet werden.

10.1055/s-0032-1311437

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Cardiovascular MR angiography in partial anomalous pulmonary venous connection

BMJ Case Reports (2015)

Jan Menke

A 17-year-old girl was assessed for exercise-induced hypertension. Her medical and family history were unremarkable. After fast running during school sport she had felt unwell with headache for about an hour. Subsequently, she presented to her paediatrician who measured elevated blood pressures and decided on further diagnostic work up. The 24 h blood pressure measurements were normal, but bicycle ergometry was stopped when the patient reached a high systolic/diastolic blood pressure of 256/96 mm Hg at 2.4 W/kg. Chest radiography and subsequent MRI showed an aberrant right pulmonary vein (an infracardiac type of partial anomalous pulmonary venous connection), whereas the lung was normal (no Scimitar syndrome). At that time the patient’s symptoms were minor, and she and her parents decided against diagnostic/interventional catheter angiography. Ten years later the patient opted for further diagnostics since she now …

Scimitar syndrome

Medical History

Past medical history

10.1136/bcr-2014-208678

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Cross-Spectral Analysis of Cerebral Autoregulation Dynamics in High Risk Preterm Infants during the Perinatal Period1

Pediatric Research (1997)

Jan Menke Erik Michel Stefanie Hillebrand Johanna Von Twickel Gerhard Jorch

Cerebral autoregulation

Spectral Analysis

10.1203/00006450-199711000-00023

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Citations (55)

Evaluating Machine Learning Models for the Fast Identification of Contingency Cases

Authorea (Authorea) (2020)

Florian Schaefer Jan Menke Martin Braun

Fast approximations of power flow results are beneficial in power system planning and live operation. In planning, millions of power flow calculations are necessary if multiple years, different control strategies, or contingency policies are to be considered. In live operation, grid operators must assess if grid states comply with contingency requirements in a short time. In this paper, we compare regression and classification methods to either predict multi-variable results, e.g., bus voltage magnitudes and line loadings, or binary classifications of time steps to identify critical loading situations. We test the methods on three realistic power systems based on time series in 15min and 5min resolution of one year. We compare different machine learning models, such as multilayer perceptrons (MLPs), decision trees, k-nearest neighbors, gradient boosting, and evaluate the required training time and prediction times as well as the prediction errors. We additionally determine the amount of training data needed for each method and show results, including the approximation of untrained curtailment of generation. Regarding the compared methods, we identified the MLPs as most suitable for the task. The MLP-based models can predict critical situations with an accuracy of 97-98% and a very low number of false negative predictions of 0.0-0.64%.

Boosting

Gradient boosting

Perceptron

Identification

Contingency table

Contingency

10.22541/au.159845944.43030810

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Extra-vascular findings in patients undergoing magnetic resonance angiography of the abdomen, pelvis and lower extremities: A retrospective study of 352 patients

Vascular (2017)

Jan M Sohns Jan Menke Leonard Bergau Bernhard G. Weiss Sebastian Schmuck

Background The aim of this study was to assess the prevalence and clinical significance of extra-vascular findings in patients undergoing magnetic resonance angiography of the abdomen, pelvis and lower extremities. Materials and methods Three hundred fifty-two patients underwent abdominal, pelvic and lower extremity 1.5 T magnetic resonance angiography. Clinically relevant vascular and extra-vascular findings were identified. Relevant vascular findings were classified as stenosis, occlusion, aneurysm, sclerosis, dissection or vasculitis. Relevant extra-vascular findings were categorized as 'safe' (Group A), intermediate - requiring additional investigation - (Group B) and malignant/endangering - requiring change of therapy (Group C). Results A total of 2152 clinically relevant vascular findings was identified (6.1/patient). The most frequent vascular finding was femoral artery stenosis (10.6%). Four hundred fifty-one extra-vascular findings were observed (1.3/patient) and classified into Group A (78%), Group B (19.5%) and Group C findings (2.4%). The most frequent malignant findings were lung cancer, lymphoma, osteosarcoma, hepatocellular carcinoma and renal cell carcinoma (7/352 patients). Conclusions Extravascular findings are frequently encountered in magnetic resonance angiography performed for vascular indications. Clinically relevant findings are seen in a substantial part of patients and should prompt further diagnostic work-up.

Magnetic resonance angiography

Vascular occlusion

10.1177/1708538117714401

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Citations (3)