Perfusion Imaging to select patients with large ischemic core for mechanical thrombectomy

International audienceBackground and purpose: Patients with acute ischemic stroke, proximal vessel occlusion and a large ischemic core at presentation are commonly not considered for mechanical thrombectomy (MT). We tested the hypothesis that in patients with baseline large infarct cores, identification of remaining penumbral tissue using perfusion imaging would translate to better outcomes after MT.Methods: This was a multicenter, retrospective, core lab adjudicated, cohort study of adult patients with proximal vessel occlusion, a large ischemic core volume (diffusion weighted imaging volume ≥70 mL), with pre-treatment magnetic resonance imaging perfusion, treated with MT (2015 to 2018) or medical care alone (controls; before 2015). Primary outcome measure was 3-month favorable outcome (defined as a modified Rankin Scale of 0-3). Core perfusion mismatch ratio (CPMR) was defined as the volume of critically hypo-perfused tissue (Tmax >6 seconds) divided by the core volume. Multivariable logistic regression models were used to determine factors that were independently associated with clinical outcomes. Outputs are displayed as adjusted odds ratio (aOR) and 95% confidence interval (CI).Results: A total of 172 patients were included (MT n=130; Control n=42; mean age 69.0±15.4 years; 36% females). Mean core-volume and CPMR were 102.3±36.7 and 1.8±0.7 mL, respectively. As hypothesized, receiving MT was associated with increased probability of favorable outcome and functional independence, as CPMR increased, a difference becoming statistically significant above a mismatch-ratio of 1.72. Similarly, receiving MT was also associated with favorable outcome in the subgroup of 74 patients with CPMR >1.7 (aOR, 8.12; 95% CI, 1.24 to 53.11; P=0.028). Overall (prior to stratification by CPMR) 73 (42.4%) patients had a favorable outcome at 3 months, with no difference amongst groups.Conclusion: s In patients currently deemed ineligible for MT due to large infarct ischemic cores at baseline, CPMR identifies a subgroup strongly benefiting from MT. Prospective studies are warranted

Teaching Video NeuroImage: Dural Angioleiomyoma: Insights From Dynamic Imaging

International audienceNo abstract availabl

Cerebral amyloid angiopathy-related acute lobar intra-cerebral hemorrhage: diagnostic value of plain CT

International audienceBackground Diagnosing probable cerebral amyloid angiopathy (CAA) after lobar intra-cerebral hemorrhage (l-ICH) currently relies on the MR-based modified Boston criteria (mBC). However, MRI has limited availability and the mBC have moderate sensitivity, with isolated l-ICH being classified as "possible CAA". A recent autopsy-based study reported potential value of finger-like projections (FLP) and subarachnoid hemorrhage (SAH) on acute CT. Here we assessed these markers' performance in a cohort most of whom survived the index episode. Methods We included all patients from a prospective pathology database with non-traumatic l-ICH, admission CT and available tissue sample showing no alternative cause. CT was assessed by two blinded independent neuroradiologists. Interobserver reproducibility was almost perfect for SAH and substantial for FLP. Results Sixteen patients were eligible [age 65.8 ± 7.2 yrs; hematoma volume: 39(26, 71)mls; hematoma evacuation sample 15 patients; autopsy one patient]. MRI was available in 11 patients. ICH-related death affected six patients. Aβ 40-42 immunohistochemistry revealed CAA in seven patients (44%). SAH and FLP were present in 12/16 (75%) and 10/16 (62%) patients, respectively. SAH had 100% sensitivity for CAA but low specificity; FLP had lower performance. Using either pathology or MRI as reference standard yielded essentially similar results. All patients with possible CAA on MRI but CAA on pathology had SAH. Conclusions In patients with moderate-size l-ICH who mostly survived the index event, SAH had perfect sensitivity and better performance than FLP. In addition, SAH appeared to add onto MRI in possible CAA, the clinically most relevant scenario. Studies in larger samples are however warranted

Computer-aided diagnosis (CAD) of subsolid nodules: Evaluation of a commercial CAD system

International audienc

Anatomical and functional MR imaging to define tumoral boundaries and characterize lesions in neuro-oncology

International audienceNeuroimaging and especially MRI has emerged as a necessary imaging modality to detect, measure, characterize and monitor brain tumors. Advanced MRI sequences such as perfusion MRI, diffusion MRI and spectroscopy as well as new post-processing techniques such as automatic segmentation of tumors and radiomics play a crucial role in characterization and follow up of brain tumors. The purpose of this review is to provide an overview on anatomical and functional MR imaging use for brain tumors boundaries determination and tumor characterization in the specific context of radiotherapy. The usefulness of anatomical and functional MR imaging on particular challenges posed by radiotherapy such as pseudoprogression and pseudoresponse and new treatment strategies such as dose painting is also described.Les avancées en neuro-imagerie, principalement liées au développement de l’IRM, ont rendu cette modalité centrale dans la prise en charge des patients porteurs de tumeur cérébrale. L’IRM, par son approche anatomique, permet de détecter, localiser et caractériser les lésions. L’application de séquences avancées d’IRM de type imagerie de perfusion, de spectroscopie ou de diffusion, ainsi que les nouveaux post-traitements permettant une segmentation ou une caractérisation automatique des lésions, apportent de nouvelles possibilités pour affiner la caractérisation des tumeurs tant au moment du diagnostic initial que lors du traitement par radiothérapie et du suivi. Le but de cette revue de littérature est de donner un aperçu de l’utilisation des imageries IRM anatomique et fonctionnelle utilisées pour la détermination des contours des différentes tumeurs cérébrales dans le contexte particulier de la radiothérapie. L'utilité de l'IRM anatomique et fonctionnelle est également examinée, en portant une attention particulière aux défis posés par la radiothérapie, tels que la pseudoprogression et la pseudoréponse, ainsi que par de nouvelles stratégies de traitement personnalisées, comme la dose painting

Can novel CT-and MR-based neuroimaging biomarkers further improve the etiological diagnosis of lobar intra-cerebral hemorrhage?

International audienceLobar hematomas represent around half of all supratentorial hemorrhages and have high mortality and morbidity. Their management depends on the underlying cause. Apart from local causes such as vascular malformation, which are rare and can usually be easily excluded thanks to imaging, the vast majority of lobar hematomas equally frequently result from either hypertensive arteriolopathy (HA) or cerebral amyloid angiopathy (CAA). Distinguishing between CAA and HA is important for prognostication (risk of recurrence nearly sevenfold higher in the former), for decision-making regarding, e.g., antithrombotic therapies (for other indications) and for clinical trials of new therapies. Currently, a non-invasive diagnosis of probable CAA can be made using the MR-based modified Boston criteria, which have excellent specificity but moderate sensitivity against histopathological reference, leading to the clinically largely irrelevant diagnosis of "possible CAA". Furthermore, the Boston criteria cannot be applied when both lobar and deep MRI hemorrhagic markers are present, a not uncommon situation. Here we propose to test whether new CT and MR-based imaging biomarkers, namely finger-like projections of the hematoma and adjacent subarachnoid hemorrhage on acute-stage CT or MRI, and remote punctate diffusion-weighted imaging ischemic lesions on acute or subacute-stage MRI, have the potential to improve the performance of the Boston criteria. Furthermore, we also propose to test whether clinical-radiological biomarkers may also allow a positive diagnosis of HA to be made in lobar hematomas, which, if feasible, would not only further reduce the prevalence of "possible CAA" but also permit a diagnosis of HA and/or CAA to be made in the presence of mixed deep and lobar MRI hemorrhagic markers

Meningioma in patients exposed to progestin drugs: results from a real-life screening program

International audiencePurpose: To report the results of systematic meningioma screening program implemented by French authorities in patients exposed to progestin therapies (cyproterone (CPA), nomegestrol (NA), and chlormadinone (CMA) acetate). Methods: We conducted a prospective monocentric study on patients who, between September 2018 and April 2021, underwent standardized MRI (injection of gadolinium, then a T2 axial FLAIR and a 3D-T1 gradient-echo sequence) for meningioma screening. Results: Of the 210 included patients, 15 (7.1%) had at least one meningioma; seven (7/15, 47%) had multiple meningiomas. Meningiomas were more frequent in older patients and after exposure to CPA (13/103, 13%) compared to NA (1/22, 4%) or CMA (1/85, 1%; P=0.005). After CPA exposure, meningiomas were associated with longer treatment duration (median=20 vs 7 years, P=0.001) and higher cumulative dose (median=91 g vs. 62 g, P=0.014). Similarly, their multiplicity was associated with higher dose of CPA (median=244 g vs 61 g, P=0.027). Most meningiomas were ≤1 cm 3 (44/58, 76%) and were convexity meningiomas (36/58, 62%). At diagnosis, patients were non-symptomatic, and all were managed conservatively. Among 14 patients with meningioma who stopped progestin exposure, meningioma burden decreased in 11 (79%) cases with no case of progression during MR follow-up. Conclusion: Systematic MR screening in progestin-exposed patients uncovers small and multiple meningiomas, which can be managed conservatively, decreasing in size after progestin discontinuation. The high rate of meningiomas after CPA exposure reinforces the need for systematic screening. For NA and CMA, further studies are needed to identify patients most likely to benefit from screening

Experience with postmortem computed tomography in the forensic analysis of the November 2015 Paris attacks

International audienceno abstract availabl

Deep learning-based noise reduction preserves quantitative MRI biomarkers in patients with brain tumors

International audienceThe use of relaxometry and Diffusion-Tensor Imaging sequences for brain tumor assessment is limited by their long acquisition time. We aim to test the effect of a denoising algorithm based on a Deep Learning Reconstruction (DLR) technique on quantitative MRI parameters while reducing scan time. In 22 consecutive patients with brain tumors, DLR applied to fast and noisy MR sequences preserves the mean values of quantitative parameters (fractional anisotropy, mean diffusivity, T1 and T2-relaxation time) and produces maps with higher structural similarity compared to long duration sequences. This could promote wider use of these biomarkers in clinical setting