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result(s) for
"Roder, Constantin"
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Vascular risk profile and changes of arterial hypertension after surgical revascularization in adult Moyamoya patients
by
Khan, Nadia
,
Feucht, Daniel
,
Roder, Constantin
in
692/1807/4024
,
692/617/375/1370
,
692/617/375/380
2024
Moyamoya disease (MMD) is a rare stenoocclusive cerebral vasculopathy often treated by neurosurgical revascularization using extracranial-intracranial bypasses to prevent ischemic or hemorrhagic events. Little is known about the vascular risk profile of adult MMD patients compared to the general population. We therefore analyzed 133 adult MMD patients and compared them with data from more than 22,000 patients from the German Health Update database. Patients with MMD showed an age- and sex-adjusted increased prevalence of arterial hypertension, especially in women between 30 and 44 years and in patients of both sexes between 45 and 64 years. Diabetes mellitus was diagnosed significantly more frequently in MMD patients with increasing age, whereas the vascular risk profile in terms of obesity, nicotine and alcohol consumption was similar to that of the general population. Antihypertensive medication was changed one year after surgical revascularization in 67.5% of patients with a tendency towards dose reduction in 43.2% of all patients. After revascularization, physicians need to be aware of a high likelihood of changes in arterial hypertension and should adjust all other modifiable systemic vascular risk factors to achieve the best treatment possible.
Journal Article
Hemodynamic evaluation of patients with Moyamoya Angiopathy: comparison of resting-state fMRI to breath-hold fMRI and 15Owater PET
by
Khan, Nadia
,
Ernemann, Ulrike
,
Roder, Constantin
in
Acetazolamide
,
Blood flow
,
Brain - blood supply
2022
Purpose
Patients with Moyamoya Angiopathy (MMA) require hemodynamic evaluation to assess the risk of stroke. Assessment of cerebral blood flow with [
15
O]water PET and acetazolamide challenge is the diagnostic standard for the evaluation of the cerebral perfusion reserve (CPR). Estimation of the cerebrovascular reactivity (CVR) by use of breath-hold-triggered fMRI (bh-fMRI) as an index of CPR has been proposed as a reliable and more readily available approach. Recent findings suggest the use of resting-state fMRI (rs-fMRI) which requires minimum patient compliance. The aim of this study was to compare rs-fMRI to bh-fMRI and [
15
O]water PET in patients with MMA.
Methods
Patients with MMA underwent rs-fMRI and bh-fMRI in the same MRI session. Maps of the CVR gained by both modalities were compared retrospectively by calculating the correlation between the mean CVR of 12 volumes of interest. Additionally, the rs-maps of a subgroup of patients were compared to CPR-maps gained by [
15
O]water PET.
Results
The comparison of the rs-maps and the bh-maps of 24 patients revealed a good correlation (Pearson’s
r
= 0.71 ± 0.13; preoperative patients: Pearson’s
r
= 0.71 ± 0.17; postoperative patients: Pearson’s
r
= 0.71 ± 0.11). The comparison of 7 rs-fMRI data sets to the corresponding [
15
O]water PET data sets also revealed a high level of agreement (Pearson’s
r
= 0.80 ± 0.19).
Conclusion
The present analysis indicates that rs-fMRI might be a promising non-invasive method with almost no patient cooperation needed to evaluate the CVR. Further prospective studies are required.
Journal Article
Whole-exome sequencing reveals the genetic causes and modifiers of moyamoya syndrome
by
Akagawa, Hiroyuki
,
Hara, Shoko
,
Nakamura, Akikazu
in
631/208/2489/144
,
692/617/375/1370
,
692/617/375/534
2024
Moyamoya vasculopathy secondary to various genetic disorders is classified as moyamoya syndrome (MMS). Recent studies indicate MMS occurs due to a combination of genetic modifiers and causative mutations for the primary genetic disorders. We performed whole-exome sequencing (WES) in 13 patients with various genetic disorders who developed MMS. WES successfully revealed the genetic diagnoses of neurofibromatosis type 1 (NF-1), Down syndrome, multisystemic smooth muscle dysfunction syndrome, Noonan syndrome, and alpha thalassemia. The previously reported modifier genes,
RNF213
and
MRVI1
, were confirmed in the NF-1 and Down syndrome cases. Further analysis revealed rare hypomorphic variants in the causative genes of the primary disorders underlying MMS, such as Alagille syndrome and Rasopathies, conferred susceptibility to MMS. Genes involved in the development of pulmonary arterial hypertension (PAH), such as
ABCC8
and
BMPR2
, were also identified as potential modifiers. The rare variants in the MMS and PAH genes were significantly enriched in the eight Japanese patients with MMS compared with the 104 Japanese individuals from the 1000 Genomes Project. Disease genes associated with the arterial occlusive conditions represented by those of Rasopathies and PAH may provide novel diagnostic markers and future therapeutic targets for MMS as well as moyamoya disease with an unknown cause.
Journal Article
Cerebrovascular Reactivity Assessment with Breath-Hold Functional MRI in Patients with Moyamoya Angiopathy: Which Time Period to Analyze?
by
Khan, Nadia
,
Ernemann, Ulrike
,
Roder, Constantin
in
[15O]water PET
,
breath-hold functional MRI
,
cerebrovascular reactivity
2026
Background/Objectives: Quantifying cerebrovascular reactivity (CVR) is essential for stroke risk assessment in patients with Moyamoya Angiopathy (MMA). Breath-hold functional MRI (bh-fMRI) is an easily implementable method to assess CVR. Determining the optimal time period of the BOLD signal for analyzing the best bh-fMRI data quality remains an open question. Methods: A retrospective analysis of 46 bh-fMRI data sets of MMA patients was conducted. The percentage BOLD signal changes were evaluated at different time periods (time point of the maximum cerebellar signal peak (TPcereb. max) ± 0 s, TPcereb. max ± 1 s, TPcereb. max ± 2 s, TPcereb. max ± 3 s, TPcereb. max ± 4 s, TPcereb. max ± 5 s). The agreement between the bh-fMRI maps and [15O]water PET maps was independently and consensually rated on a 4-point Likert scale (1 = poor, 2 = moderate, 3 = good, 4 = excellent) and compared with the Friedman test. The inter-rater agreement was calculated separately for each time period using quadratic weighted Cohen’s kappa κw. Results: The selected time period had a significant impact on the agreement between bh-fMRI and [15O]water PET (χ2(5) = 79.448, p < 0.001, W = 0.345). Short time periods of TPcereb.max ± 0 s or TPcereb.max ±1 s demonstrated the highest level of concordance between bh-fMRI and [15O]water PET (median = 3.5 for TPcereb.max ± 0 s; median = 3 for TPcereb.max ± 1 s, modus = 4 in both cases). The agreement between bh-fMRI and [15O]water PET was significantly higher when evaluating time periods of TPcereb.max ± 0 s than when evaluating all time periods ≥ TPcereb. max ± 2 s. The inter-rater agreement was almost perfect for all time periods except one (TPcereb. max ± 1 s). Conclusions: Short time periods should be selected when evaluating CVR with bh-fMRI, as this study suggests a high level of validity in comparison to [15O]water PET.
Journal Article
Multidisciplinary, Clinical Assessment of Accelerated Deep-Learning MRI Protocols at 1.5 T and 3 T After Intracranial Tumor Surgery and Their Influence on Residual Tumor Perception
by
Ernemann, Ulrike
,
Feucht, Daniel
,
Staber, Deborah
in
Algorithms
,
Artificial intelligence
,
Brain cancer
2025
Background/Objectives: Postoperative MRI is crucial for detecting residual tumor, identifying complications, and planning subsequent therapy. This study evaluates accelerated deep learning reconstruction (DLR) versus standard clinical protocols for early postoperative MRI following tumor resection. Methods: This study uses a multidisciplinary approach involving a neuroradiologist, neurosurgeon, neuro-oncologist, and radiotherapist to evaluate qualitative aspects using a 5-point Likert scale, the preferred reconstruction variant and potential residual tumor of DLR and conventional reconstruction (CR) of FLAIR, T1-weighted non-contrast and contrast-enhanced (T1), and coronal T2-weighted (T2) sequences for 1.5 and 3 T MRI. Quantitative analysis included the image quality metrics Structural Similarity Index (SSIM), Multi-Scale SSIM (MS-SSIM), Feature Similarity Index (FSIM), Noise Quality Metric (NQM), signal-to-noise ratio (SNR), and Peak SNR (PSNR) with CR as a reference. Results: All raters strongly preferred DLR over CR. This was most pronounced for FLAIR images at 1.5 and 3 T (91% at 1.5 T and 97% at 3 T) and least pronounced for T1 at 1.5 T (79% for non-contrast-enhanced and 84% for contrast-enhanced sequences) and for T2 at 3 T (69%). DLR demonstrated superior qualitative image quality for all sequences and field strengths (p < 0.001), except for T2 at 3 T, which was observed across all raters (p = 0.670). Diagnostic confidence was similar at 3 T with better but non-significant differences for T2 (p = 0.134) and at 1.5 T with better but non-significant differences for non-contrast-enhanced T1 (p = 0.083) and only marginally significant results for FLAIR (p = 0.033). Both the SSIM and MS-SSIM indicated near-perfect similarity between CR and DLR. FSIM performs worse in terms of consistency between CR and DLR. The image quality metrics NQM, SNR, and PSNR showed better results for DLR. Visual assessment of residual tumor was similar at 3 T but differed at 1.5 T, with more residual tumor detected with DLR, especially by the neurosurgeon (n = 4). Conclusions: An accelerated DLR protocol demonstrates clinical feasibility, enabling high-quality reconstructions in challenging postoperative MRIs. DLR sequences received strong multidisciplinary preference, underscoring their potential to improve neuro-oncologic decision making and suitability for clinical implementation.
Journal Article
Quantification of High-Resolution Contrast-Enhanced T1-Weighted Vessel Wall MRI for Predicting Disease Progression in Moyamoya Disease
by
Vogl, Daniel
,
Wiggenhauser, Lucas
,
Khan, Nadia
in
Arteries
,
Correlation analysis
,
Development and progression
2025
Objective: In moyamoya disease (MMD), the internal carotid and proximal cerebral arteries narrow, potentially leading to stroke or hemorrhage from fragile collaterals. Disease activity and progression may be detected by contrast-enhanced (CE) high-resolution (HR) vessel wall imaging (CE-VWI) on T1-weighted MRI. However, this imaging approach needs standardization for the evaluation of signal intensity and longitudinal reproducibility. Methods: MMD patients with at least two separate CE-VWI examinations on the same and on different scanners were included. Signal intensity of the vessel wall, pituitary stalk, and temporal lobe white matter were measured and normalized using manually selected regions of interest. Intraindividual longitudinal reproducibility of MRI was analyzed and the clinical course was correlated with vessel wall enhancement data. Results: Eighty-seven patients were analyzed. Primary analysis included 60 patients with two or more CE-VWI measurements (n = 129) with median 14.8 months between examinations (range: 2–36 months) on the same scanner. Intraindividual variation in pituitary stalk enhancement (positive control) and temporal lobe white matter enhancement (negative control) showed median signal variability of 20.5% and 17.5%, respectively. The pituitary-to-temporal lobe signal intensity ratio remained stable over time (p = 0.843) with 9.4% median variability. Correlation analysis revealed a significant positive association between pituitary and temporal lobe signal changes (ρ = 0.717, p < 0.001). A total of 75% of patients showed vessel wall contrast enhancement with fluctuating signal intensity over approximately 15.9 months, likely depicting disease activity. Conclusions: CE-VWI is important for screening disease activity in moyamoya patients. Our findings demonstrate longitudinal intraindividual reproducibility when normalized to pituitary stalk, enabling quantified evaluation of disease progression through longitudinal vessel wall contrast-enhancement changes.
Journal Article
Intravoxel incoherent motion diffusion-weighted MR imaging of gliomas: feasibility of the method and initial results
2013
Introduction
The purpose of this study was to evaluate the feasibility of intravoxel incoherent motion (IVIM) imaging and its value in differentiating the histologic grade among human gliomas.
Methods
The IVIM model generated parametric images for apparent diffusion coefficient ADC, slow diffusion coefficient
D
(or
D
slow
), fast diffusion coefficient
D
* (or
D
fast
), and fractional perfusion-related volume
f
in 22 patients with gliomas (WHO grade II–IV) using monopolar Stejskal–Tanner diffusion-weighted imaging (DWI) scheme and 14
b
values ranging from 0 s/mm
2
to a maximum of 1,300 s/mm
2
. A region-of-interest analysis on the tumor as well as in the white matter was conducted. The parameter values were tested for significant differences. The repeatability of the measurements was tested by coefficient of variation and Bland–Altman plots.
Results
D
,
D
*, and
f
in the high-grade gliomas demonstrated significant differences compared to the healthy white matter.
D
* and
f
showed a significant difference between low- and high-grade gliomas.
D
tended to be slightly lower in the WHO grade II compared to WHO grade III–IV tumors.
f
and
D
* demonstrated higher coefficients of variation than the ADC and
D
in tumor. The Bland–Altman plots demonstrated satisfactory results without any outliers outside the mean ± 1.96 standard deviation.
Conclusion
The IVIM-fitted post-processing of DWI-signal decay in human gliomas could show significantly different values of fractional perfusion-related volume and fast diffusion coefficient between low- and high-grade tumors, which might enable a noninvasive WHO grading in vivo.
Journal Article
Genome-wide association study of intracranial aneurysm identifies three new risk loci
by
von und zu Fraunberg, Mikael
,
Risselada, Roelof
,
Perret, Claire
in
631/208/205/2138
,
631/208/727/2000
,
692/699/375/1370
2010
Murat Gunel and colleagues report a genome-wide association study for intracranial aneurysm and identify risk variants near
RBBP8
,
CNNM
and
STARD13
.
Saccular intracranial aneurysms are balloon-like dilations of the intracranial arterial wall; their hemorrhage commonly results in severe neurologic impairment and death. We report a second genome-wide association study with discovery and replication cohorts from Europe and Japan comprising 5,891 cases and 14,181 controls with ∼832,000 genotyped and imputed SNPs across discovery cohorts. We identified three new loci showing strong evidence for association with intracranial aneurysms in the combined dataset, including intervals near
RBBP8
on 18q11.2 (odds ratio (OR) = 1.22,
P
= 1.1 × 10
−12
),
STARD13
-
KL
on 13q13.1 (OR = 1.20,
P
= 2.5 × 10
−9
) and a gene-rich region on 10q24.32 (OR = 1.29,
P
= 1.2 × 10
−9
). We also confirmed prior associations near
SOX17
(8q11.23–q12.1; OR = 1.28,
P
= 1.3 × 10
−12
) and
CDKN2A
-
CDKN2B
(9p21.3; OR = 1.31,
P
= 1.5 × 10
−22
). It is noteworthy that several putative risk genes play a role in cell-cycle progression, potentially affecting the proliferation and senescence of progenitor-cell populations that are responsible for vascular formation and repair.
Journal Article
Retrospective longitudinal assessment of optic nerve sheath diameter in patients with malignant glioma
2023
Introduction Glioblastoma (GBM) is a tumor with rapid growth and a possible relationship to elevated intracranial pressure (ICP). High ICP may not always be associated with clinical signs. A non‐invasive technique for assessment of ICP is measuring the optic nerve sheath diameter (ONSD). Identifying patients who need immediate intervention is of importance in neuro‐oncological care. The goal of this study is to assess the available magnetic resonance imaging (MRI) of patients with GBM with respect to pre‐ and postoperative ONSD. Methods and Materials Retrospective data analysis was performed on all patients operated for GBM at a tertiary care center between 2010 and 2020. Two pre and one postoperative MRI had to be available. Clinical data and ONSD at multiple time points were analyzed and correlated, as well as preoperative volumetrics. Results Sixty‐seven patients met the inclusion criteria. Clinical signs of elevated ICP were seen in 25.4% (n = 17), while significant perifocal edema was present in 67.2% (n = 45) of patients. Clinical signs of preoperatively elevated ICP were associated with significantly elevated ONSD at diagnosis (p < 0.001) as well as preoperative tumor volume (p < 0.001). Significant perifocal edema at the time of diagnosis was associated with elevated ONSD (p = 0.029) and higher tumor volume (p = 0.003). In patients with significant edema, ONSD increased significantly between preoperative MRIs (p = 0.003/005). In patients with clinical signs of raised ICP, ONSD also increased, whereas it was stable in asymptomatic patients (yes: 5.01+/−4.17 to 5.83+/−0.55 mm, p = 0.010, no: 5.17+/−0.46 mm to 5.38+/−0.41 mm, p = 0.81). A significant increase of ONSD from diagnosis to preoperative MRI and a significant decrease until 3 months postoperatively were observed (p < 0.001). Conclusions ONSD might help identify high ICP in patients with GBM. In this first‐of‐its kind study, we observed a significant increase of ONSD preoperatively, likely associated with edema. Postoperatively, ONSD decreased significantly until 3 months after surgery and increased again at 12 months. Further prospective data collection is warranted. Measurement of optical nerve sheath diameter (ONSD) is a noninvasive technique for assessment of intracranial pressure. Identifying patients at risk with the need of immediate intervention is of importance in neuro‐oncological care. This study retrospectively investigates pre‐ and postoperative ONSD in patients with glioblastoma.
Journal Article
Not taught in medical school but needed for the clinical job – leadership, communication and career management skills for final year medical students
by
Behling, Felix
,
Adib, Sasan Darius
,
Nasi-Kordhishti, Isabella
in
Adult
,
Career Choice
,
Career development
2024
Background
Starting the first job as a young physician is a demanding challenge. Certain skills are important to master this transformation that go beyond the theoretical knowledge and practical skills taught in medical school. Competencies such as communication, leadership and career management skills are important to develop as a young physician but are usually not sufficiently taught in medical school in a structured and comprehensive way.
Methods
We performed an online survey among final year medical students regarding how they perceive their current competency level in communication, leadership and career management skills. We also assessed how they rate the importance to acquire these competencies and the current emphasis during their medical school education regarding these topics.
Results
Of 450 final year medical students 80 took part in the voluntary survey and 75 complete datasets were returned (16.7%). The majority of respondents rated different communication skills, leadership skills and career management skills as important or very important for their later clinical work. However, most students felt to be poorly or very poorly prepared by the current medical school curriculum, especially for certain leadership and career management skills. Overall, 90.7% of participants expressed interest in an additional educational course that covers subjects of communication, leadership and career management skills during the later stage of medical school, preferably as a hybrid in-person session that also offers synchronous online participation.
Conclusions
The results of the survey express the need to address communication, leadership and career management skills in the medical curriculum to be better prepare students for the demands of residency and their further course as physicians. An educational format during the final year of medical school may be suitable to address mentioned topics in the framework of clinical practical exposure.
Journal Article