Contrast-enhanced MR myelography in spontaneous intracranial hypotension: description of an artefact imitating CSF leakage

In contrast-enhanced (CE) MR myelography, hyperintense signal outside the intrathecal space in T1-weighted sequences with spectral presaturation inversion recovery (SPIR) is usually considered to be due to CSF leakage. We retrospectively investigated a hyperintense signal at the apex of the lung appearing in this sequence in patients with SIH (n = 5), CSF rhinorrhoea (n = 2), lumbar spine surgery (n = 1) and in control subjects (n = 6). Intrathecal application of contrast agent was performed in all patients before MR examination, but not in the control group. The reproducible signal increase was investigated with other fat suppression techniques and MR spectroscopy. All patients and controls showed strongly hyperintense signal at the apex of the lungs imitating CSF leakage into paraspinal tissue. This signal increase was identified as an artefact, caused by spectroscopically proven shift and broadening of water and lipid resonances (1-2 ppm) in this anatomical region. Only patients with SIH showed additional focal enhancement along the spinal nerve roots and/or in the spinal epidural space. In conclusion CE MR myelography with spectral selective fat suppression shows a reproducible cervicothoracic artefact, imitating CSF leakage. Selective water excitation technique as well as periradicular and epidural contrast collections may be helpful to discriminate between real pathological findings and artefacts

Predictors of clinical outcomes in space-occupying cerebellar infarction undergoing suboccipital decompressive craniectomy

IntroductionDespite current clinical guidelines recommending suboccipital decompressive craniectomy (SDC) in cerebellar infarction when patients present with neurological deterioration, the precise definition of neurological deterioration remains unclear and accurate timing of SDC can be challenging. The current study aimed at characterizing whether clinical outcomes can be predicted by the GCS score immediately prior to SDC and whether higher GCS scores are associated with better clinical outcomes.MethodsIn a single-center, retrospective analysis of 51 patients treated with SDC for space-occupying cerebellar infarction, clinical and imaging data were evaluated at the time points of symptom onset, hospital admission, and preoperatively. Clinical outcomes were measured by the mRS. Preoperative GCS scores were stratified into three groups (GCS, 3–8, 9–11, and 12–15). Univariate and multivariate Cox regression analyses were performed using clinical and radiological parameters as predictors of clinical outcomes.ResultsIn cox regression analysis GCS scores of 12–15 at surgery were significant predictors of positive clinical outcomes (mRS, 1–2). For GCS scores of 3–8 and 9–11, no significant increase in proportional hazard ratios was observed. Negative clinical outcomes (mRS, 3–6) were associated with infarct volume above 6.0 cm3, tonsillar herniation, brainstem compression, and a preoperative GCS score of 3–8 [HR, 2.386 (CI, 1.160–4.906); p = 0.018].ConclusionOur preliminary findings suggest that SDC should be considered in patients with infarct volumes above 6.0 cm3 and with GCS between 12 and 15, as these patients may show better long-term outcomes than those in whom surgery is delayed until a GCS score below 11

White matter alterations of the corticospinal tract in adults born very preterm and/or with very low birth weight

White matter (WM) injury, either visible on conventional magnetic resonance images (MRI) or measurable by diffusion tensor imaging (DTI), is frequent in preterm born individuals and often affects the corticospinal tract (CST). The relation between visible and invisible white mater alterations in the reconstructed CST of preterm subjects has so far been studied in infants, children and up to adolescence. Therefore, we probabilistically tracked the CST in 53 term-born and 56 very preterm and/or low birth weight (VP/VLBW, < 32 weeks of gestation and/or birth weight < 1,500 g) adults (mean age 26 years) and compared their DTI parameters (axial, radial, mean diffusivity—AD, RD, MD, fractional anisotropy—FA) in the whole CST and slice-wise along the CST. Additionally, we used the automatic, tract-based-spatial-statistics (TBSS) as an alternative to tractography. We compared control and VP/VLBW and subgroups with and without CST WM lesions visible on conventional MRI. Compared to controls, VP/VLBW subjects had significantly higher diffusivity (AD, RD, MD) in the whole CST, slice-wise along the CST, and in multiple regions along the TBSS skeleton. VP/VLBW subjects also had significantly lower (TBSS) and higher (tractography) FA in regions along the CST, but no different mean FA in the tracked CST as a whole. Diffusion changes were weaker, but remained significant for both, tractography and TBSS, when excluding subjects with visible CST lesions. Chronic CST injury persists in VP/VLBW adults even in the absence of visible WM lesions, indicating long-term structural WM changes induced by premature birth

Invasive Mold Infection of the Central Nervous System in Immunocompromised Children

Background: Due to the difficulties in the definite diagnosis, data on brain imaging in pediatric patients with central nervous system (CNS)-invasive mold infection (IMD) are scarce. Our aim was to describe brain imaging abnormalities seen in immunocompromised children with CNS-IMD, and to analyze retrospectively whether specific imaging findings and sequences have a prognostic value. Methods: In a retrospective study of 19 pediatric patients with proven or probable CNS-IMD, magnetic resonance imaging (MRI)-findings were described and analyzed. The results were correlated with outcome, namely death, severe sequelae, or no neurological sequelae. Results: 11 children and 8 adolescents (11/8 with proven/probable CNS-IMD) were included. Seven of the patients died and 12/19 children survived (63%): seven without major neurological sequelae and five with major neurological sequelae. Multifocal ring enhancement and diffusion restriction were the most common brain MRI changes. Diffusion restriction was mostly seen at the core of the lesion. No patient with disease limited to one lobe died. Perivascular microbleeding seen on susceptibility weighted imaging (SWI) and/or gradient-echo/T2* images, as well as infarction, were associated with poor prognosis. Conclusions: The presence of infarction was related to poor outcome. As early microbleeding seems to be associated with poor prognosis, we suggest including SWI in routine diagnostic evaluation of immunocompromised children with suspected CNS-IMD

Machine-learning-aided prediction of brain metastases development in non-small-cell lung cancers

Purpose Non–small-cell lung cancer (NSCLC) shows a high incidence of brain metastases (BM). Early detection is crucial to improve clinical prospects. We trained and validated classifier models to identify patients with a high risk of developing BM, as they could potentially benefit from surveillance brain MRI. Methods Consecutive patients with an initial diagnosis of NSCLC from January 2011 to April 2019 and an in-house chest-CT scan (staging) were retrospectively recruited at a German lung cancer center. Brain imaging was performed at initial diagnosis and in case of neurological symptoms (follow-up). Subjects lost to follow-up or still alive without BM at the data cut-off point (12/2020) were excluded. Covariates included clinical and/or 3D-radiomics-features of the primary tumor from staging chest-CT. Four machine learning models for prediction (80/20 training) were compared. Gini Importance and SHAP were used as measures of importance; sensitivity, specificity, area under the precision-recall curve, and Matthew's Correlation Coefficient as evaluation metrics. Results Three hundred and ninety-five patients compromised the clinical cohort. Predictive models based on clinical features offered the best performance (tuned to maximize recall: sensitivity∼70%, specificity∼60%). Radiomics features failed to provide sufficient information, likely due to the heterogeneity of imaging data. Adenocarcinoma histology, lymph node invasion, and histological tumor grade were positively correlated with the prediction of BM, age, and squamous cell carcinoma histology were negatively correlated. A subgroup discovery analysis identified 2 candidate patient subpopulations appearing to present a higher risk of BM (female patients + adenocarcinoma histology, adenocarcinoma patients + no other distant metastases). Conclusion Analysis of the importance of input features suggests that the models are learning the relevant relationships between clinical features/development of BM. A higher number of samples is to be prioritized to improve performance. Employed prospectively at initial diagnosis, such models can help select high-risk subgroups for surveillance brain MRI

Automated quantitative evaluation of brain MRI may be more accurate for discriminating preterm born adults

Objective To investigate the structural brain abnormalities and their diagnostic accuracy through qualitative and quantitative analysis in term born and very preterm birth or with very low birth weight (VP/VLBW) adults. Methods We analyzed 3-T MRIs acquired in 2011–2013 from 67 adults (27 term born controls, mean age 26.4 years, 8 females; 40 VP/VLBWs, mean age 26.6 years, 16 females). We compared automatic segmentations of the white matter, deep gray matter and cortical gray matter, manual corpus callosum measurements and visual ratings of the ventricles and white matter with t tests, logistic regression, and receiver operator characteristic (ROC) curves. Results Automatic segmentation correctly classified 84% of cases; visual ratings correctly classified 63%. Quantitative volumetry based on automatic segmentation revealed higher ventricular volume, lower posterior corpus callosum, and deep gray matter volumes in VP/VLBW subjects compared to controls (p < 0.01). Visual rating and manual measurement revealed a thinner corpus callosum in VP/VLBW adults (p = 0.04) and deformed lateral ventricles (p = 0.03) and tendency towards more “dirty” white matter (p = 0.06). Automatic/manual measures combined with visual ratings correctly classified 87% of cases. Stepwise logistic regression identified three independent features that correctly classify 81% of cases: ventricular volume, deep gray matter volume, and white matter aspect. Conclusion Enlarged and deformed lateral ventricles, thinner corpus callosum, and “dirty” white matter are prevalent in preterm born adults. Their visual evaluation has low diagnostic accuracy. Automatic volume quantification is more accurate but time consuming. It may be useful to ask for prematurity before initiating further diagnostics in subjects with these alterations

Artificial Intelligence for the Detection of Focal Cortical Dysplasia: Challenges in Translating Algorithms into Clinical Practice

Focal cortical dysplasias (FCDs) are malformations of cortical development and one of the most common pathologies causing pharmacoresistant focal epilepsy. Resective neurosurgery yields high success rates, especially if the full extent of the lesion is correctly identified and completely removed. The visual assessment of magnetic resonance imaging does not pinpoint the FCD in 30%–50% of cases, and half of all patients with FCD are not amenable to epilepsy surgery, partly because the FCD could not be sufficiently localized. Computational approaches to FCD detection are an active area of research, benefitting from advancements in computer vision. Automatic FCD detection is a significant challenge and one of the first clinical grounds where the application of artificial intelligence may translate into an advance for patients' health. The emergence of new methods from the combination of health and computer sciences creates novel challenges. Imaging data need to be organized into structured, well-annotated datasets and combined with other clinical information, such as histopathological subtypes or neuroimaging characteristics. Algorithmic output, that is, model prediction, requires a technically correct evaluation with adequate metrics that are understandable and usable for clinicians. Publication of code and data is necessary to make research accessible and reproducible. This critical review introduces the field of automatic FCD detection, explaining underlying medical and technical concepts, highlighting its challenges and current limitations, and providing a perspective for a novel research environment

White matter macro- and microstructure alterations in preterm born adults

Introduction: White matter (WM) injury, both macroscopic (visible on conventional MRI) and microscopic (detectable by diffusion tensor imaging, DTI) is frequent among preterm born infants investigated in later life (Volpe, 2009). Degree and localization vary, but the corticospinal tract (CST) is often affected (Eikenes et al., 2011). The relation between the micro- and macroscopic CST alterations has only been studied to our knowledge up to adolescence (Bassi et al., 2011, Estep et al., 2014 and Groeschel et al., 2014) but not in adults. We aimed to assess group differences in micro- and macroscopic WM integrity of the CST between preterm and full-term born adults and to evaluate the impact of macroscopic lesions onto the DTI parameters in and along the CST. Methods: As part of a prospective study of preterm birth (Bavarian Longitudinal Study), we investigated adults at 26 years of age by means of MRI. Artifact-free DTI data were available from 51 full-term and 55 preterm born subjects (<32 weeks gestation or birth weight < 1500 g). In these subjects we probabilistically reconstructed the CST (Giorgio et al., 2010) and extracted DTI parameters (mean, axial, radial diffusivity - MD, AD, RD, and fractional anisotropy, FA) in the CST and slice-wise along the CST. On FLAIR-MRI images we identified macroscopic WM lesions as hyperintensities, noted their relation to the CST and correlated their presence with the DTI. Results and discussion: WM hyperintensities, periventricular or in the corona radiata, were present in 9 of 51 (18%) full-term and 26 of 55 (47%) preterm born subjects. In 3 of 51 (6%) full-term and 17 of 55 (30%) preterm born subjects these ”lesions” affected the CST. Compared to full-term individuals, the preterm born subjects had significantly higher diffusivity (MD, AD, RD) in and along the CST but no difference in FA. These changes were weaker, but nevertheless remained significant when excluding subjects with macroscopic lesions. This suggests chronic CST injury with increased tissue water content (Aung et al., 2013) even in the absence of visible WM lesions and points towards a high susceptibility of the CST after preterm birth