Évaluation de la fidélité intra- et interobservateur pour l’évaluation du vasospasme post-hémorragie sous-arachnoïdienne en angiotomodensitométrie

Objectif: Revoir systématiquement la littérature et évaluer la fidélité intra- et inter-observateur de l’ angiotomodensitométrie (angioTDM) dans le dépistage ou le diagnostic du vasospasme cérébral (VC) après une hémorragie sous-arachnoïdienne (HSA). Méthodes: Les articles rapportant la fidélité de l’angioTDM jusqu'en mai 2018 ont été systématiquement recherchés et évalués. Onze évaluateurs ont évalué indépendamment 17 segments artériels chez 50 patients atteints de HSA pour la présence de vasospasme en utilisant une échelle de 4 catégories, subséquemment dichotomisée. Les lecteurs devaient juger de la présence ou non de vasospasme modéré à sévère (rétrécissement ≥ 50%) chez chaque patient; si les trouvailles justifiaient une augmentation du traitement médical; et / ou angiographie +/- angioplastie. Quatre évaluateurs ont réévalué les mêmes patients dans un ordre différent au moins 4 semaines plus tard. Résultats: La revue systématique a révélé que la fidélité de l’angioTDM n'avait pas été rigoureusement évaluée auparavant. La fidélité intra-évaluateur a atteint un niveau substantiel (k> 0.600) chez 3/4 lecteurs pour la détection de vasospasme modéré-sévère, mais la fidélité inter-évaluateur est restée inférieure à ce seuil même lorsque les résultats ont été stratifiés selon la spécialité et l'expérience. La fidélité était également inférieure à ce seuil pour les recommandations de traitement médical et l’indication d’angiographie. La fidélité dans l’analyse par segment était substantielle seulement lorsque 1. la gradation était dichotomisée (présence ou absence d'un rétrécissement supérieur à 50%) 2. chez les lecteurs seniors et 3. pour les segments M1 bilatéralement. L'exclusion des cas où les segments artériels étaient masqués par des artéfacts métalliques n’a pu permettre à des segments supplémentaires de franchir le seuil de 0.600. Conclusion: l’angioTDM n'était pas suffisamment fidèle entre les observateurs pour soutenir son utilisation dans le diagnostic du vasospasme et dans la prise de décision clinique chez des patients atteints d'HSA.Objective: To review the literature on and assess the intra- and inter-observer reliability of computed tomography angiography (CTA) in the screening or diagnosis of cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH). Methods: Articles reporting the reliability of CTA up to May 2018 were systematically searched and evaluated. Eleven raters independently graded 17 arterial segments in each of 50 SAH patients for the presence of vasospasm using a 4-category scale. Furthermore, readers were asked: to judge the presence or absence of any moderate/severe vasospasm (≥ 50 % narrowing); whether findings would justify augmentation of medical treatment; and/or DSA with/without angioplasty. Four raters reassessed the same patients in different order at least 4 weeks later. Results: The systematic review revealed that the reliability of CTA had not previously been rigorously assessed. The intra-rater reliability reached a substantial level (k > 0.600) in 3/4 readers for the detection of moderate-severe vasospasm, but inter-rater reliability remained below substantial even when results were stratified according to specialty and experience. There was less than substantial agreement for imaging-based recommendations (medical management or indications to proceed with DSA/angioplasty). Dichotomized per segment results (presence or absence of >50% narrowing) allowed reaching substantial agreement only among senior readers evaluating M1 segments. Excluding cases in which segments were obscured by metal artifacts did not allow additional arterial segments to reach the threshold for substantial agreement. Conclusion: CTA was not sufficiently repeatable among observers diagnosing CV to support a general use in guiding decisions in the clinical management of SAH patients

Non-contrast CT markers of intracerebral hematoma expansion : a reliability study

Objectives: We evaluated whether clinicians agree in the detection of non-contrast CT markers of intracerebral hemorrhage (ICH) expansion. Methods: From our local dataset, we randomly sampled 60 patients diagnosed with spontaneous ICH. Fifteen physicians and trainees (Stroke Neurology, Interventional and Diagnostic Neuroradiology) were trained to identify six density (Barras density, black hole, blend, hypodensity, fluid level, swirl) and three shape (Barras shape, island, satellite) expansion markers, using standardized definitions. Thirteen raters performed a second assessment. Inter and intra-rater agreement were measured using Gwet’s AC1, with a coefficient > 0.60 indicating substantial to almost perfect agreement. Results: Almost perfect inter-rater agreement was observed for the swirl (0.85, 95% CI: 0.78-0.90) and fluid level (0.84, 95% CI: 0.76-0.90) markers, while the hypodensity (0.67, 95% CI: 0.56-0.76) and blend (0.62, 95% CI: 0.51-0.71) markers showed substantial agreement. Inter-rater agreement was otherwise moderate, and comparable between density and shape markers. Inter-rater agreement was lower for the three markers that require the rater to identify one specific axial slice (Barras density, Barras shape, island: 0.46, 95% CI: 0.40-0.52 versus others: 0.60, 95% CI: 0.56-0.63). Inter-observer agreement did not differ when stratified for raters’ experience, hematoma location, volume or anticoagulation status. Intrarater agreement was substantial to almost perfect for all but the black hole marker. Conclusion: In a large sample of raters with different backgrounds and expertise levels, only four of nine non-contrast CT markers of ICH expansion showed substantial to almost perfect inter-rater agreement

Perimacular Ganglion Cell Complex Thinning Detected By Spectral-Domain OCT Useful In Detecting Optic Tract Syndrome

"Unilateral lesions to the optic tract lead to optic nerve atrophy (bow-tie atrophy) and concurrent macular ganglion cell complex (GCC) thickness reduction in a reproducible pattern in both eyes. This is called optic tract syndrome and it is reflected clinically as an incongruous homonymous hemianopia and a contralateral relative afferent pupillary defect (RAPD).

Should Magnetic Resonance Angiography Be Used for Screening of Intracranial Aneurysm in Adults with Sickle Cell Disease?

Magnetic resonance imaging (MRI) is used in patients with sickle cell disease (SCD) to detect silent cerebral infarcts. MR angiography (MRA) can identify arterial stenoses and intracranial aneurysms (ICANs) associated with SCD. In this study, we aimed to estimate the prevalence of ICANs in asymptomatic adult patients with SCD referred from the SCD clinic for routine screening by MRI/MRA using a 3T-MRI scanner. Findings were independently reviewed by two neuroradiologists. Between 2016 and 2020, 245 asymptomatic adults with SCD were stratified according to genotype (SS/S-β0thalassemia and SC/Sβ+). ICANs were found in 27 patients (11%; 0.95 CI: 8–16%). ICANs were more frequent in SS/S-β0thalassemia patients (20/118 or 17%; 0.95 CI: 11–25%) than in SC/βb+ patients (7/127 or 6%; 0.95 CI: 2–11%; p = 0.007). Individuals with SCD (particularly SS/S-β0thalassemia) have a higher prevalence of ICANs than the general population. We believe that MRA should be considered in the current American Society of Hematology guidelines, which already contain a recommendation for MRI at least once in adult SCD patients. However, the clinical significance of preventive treatment of unruptured aneurysms remains controversial

Magnetic Resonance-Guided Radiation Therapy for Head and Neck Cancers

Despite the significant evolution of radiation therapy (RT) techniques in recent years, many patients with head and neck cancer still experience significant toxicities during and after treatments. The increased soft tissue contrast and functional sequences of magnetic resonance imaging (MRI) are particularly attractive in head and neck cancer and have led to the increasing development of magnetic resonance-guided RT (MRgRT). This approach refers to the inclusion of the additional information acquired from a diagnostic or planning MRI in radiation treatment planning, and now extends to online high-quality daily imaging generated by the recently developed MR-Linac. MRgRT holds numerous potentials, including enhanced baseline and planning evaluations, anatomical and functional treatment adaptation, potential for hypofractionation, and multiparametric assessment of response. This article offers a structured review of the current literature on these established and upcoming roles of MRI for patients with head and neck cancer undergoing RT