Journal of neuroimaging : official journal of the American Society of Neuroimaging
-
Several studies in the literature have attempted to subjectively assess the degree of visualization of different neurovascular structures using different contrast agents and concentrations. Given the recent contrast shortages, we aim to objectively compare the radiopacity achieved with four angiographic contrast agents used in clinical practice. ⋯ Isovue 370 provides the highest HU radiopacity and the most accurate aneurysm measurements. Angiographic measurements obtained with Isovue 300 may underestimate the actual aneurysmal dimensions. Visipaque 320 and Omnipaque 300 at 100% concentration have similar mean HUs and are beneficial for patients with chronic kidney or cardiac disease.
-
Multicenter Study
Intersite brain MRI volumetric biases persist even in a harmonized multisubject study of multiple sclerosis.
Multicenter study designs involving a variety of MRI scanners have become increasingly common. However, these present the issue of biases in image-based measures due to scanner or site differences. To assess these biases, we imaged 11 volunteers with multiple sclerosis (MS) with scan and rescan data at four sites. ⋯ Differences in brain volumetry persisted across MR scanners despite protocol harmonization. These differences were not well explained by variance component modeling; however, statistical innovations for mitigating intersite differences show promise in reducing biases in multicenter studies of MS.
-
Wernicke's encephalopathy (WE) is a severe acute disorder related to thiamine deficiency. This study was aimed at revealing the relationship between clinical and imaging findings and WE recovery. ⋯ The early recovered group showed a lower incidence of T2WI/FLAIR abnormality in atypical sites and diffusion signal abnormality in total or typical sites with a lower incidence of cerebellar ataxia.
-
Ultrasonographic optic nerve sheath (ONS) diameter is a noninvasive intracranial pressure (ICP) surrogate. ICP is monitored invasively in specialized intensive care units. Noninvasive ICP monitoring is important in less specialized settings. However, noninvasive ICP monitoring using ONS diameter (ONSD) is limited by the need for experts to obtain and perform measurements. We aim to automate ONSD measurements using a deep convolutional neural network (CNN) with a novel masking technique. ⋯ A CNN can learn ONSD measurement using masking without image segmentation or landmark detection.
-
Quantitative CT perfusion (CTP) thresholds for assessing the extent of ischemia in patients with acute ischemic stroke (AIS) have been established; relative cerebral blood flow (rCBF) <30% is typically used for estimating estimated ischemic core volume and Tmax (time to maximum) >6 seconds for critical hypoperfused volume in AIS patients with large vessel occlusion (LVO). In this study, we aimed to identify the optimal threshold values for patients presenting with AIS secondary to distal medium vessel occlusions (DMVOs). ⋯ In AIS patients with DMVOs, longer Tmax delays than Tmax > 6 seconds, most notably, Tmax > 10 seconds, best predict FIV in unsuccessfully recanalized patients. No CTP threshold reliably predicts FIV in the successfully recanalized group nor significantly outperformed rCBF < 30%.