====== Diffusion-weighted imaging in stimulated echo acquisition mode ======

[[Diffusion-weighted imaging]] in stimulated echo acquisition mode ([[STEAM-DWI]]) is an interesting alternative with less [[susceptibility artifact]]s compared to the most commonly used [[diffusion-weighted echo-planar imaging]] ([[EPI-DWI]]). [[Sensitivity]] and [[specificity]] of a novel [[STEAM-DWI]], described by Merrem et al. [[2017]], were assessed in patients with [[ischemic stroke]].

EPI- and STEAM-DWIs were performed in patients with suspected subacute stroke between 01 July 2019 and 30 June 2020 using 3-T MRI. Three neuroradiologists independently and separately rated STEAM-DWI images with respect to (i) signs of an acute/subacute stroke, (ii) the number, size and localization of infarctions and, (iii) the presence of artifacts.

In 55 (23 right, 23 left, 9 both hemispheres) of 85 patients a subacute stroke was confirmed using EPI-DWI. The cerebral vascular territories were affected as follows: anterior cerebral artery 8 %, middle cerebral artery 48 %, posterior cerebral artery 27 %, brainstem 7 %, cerebellum 10 %. In 53 of 55 (96 %) cases the stroke was detected by usage of STEAM-DWI, in 35 of 37 patients microembolic events were noticed (95 %). Results showed a sensitivity and specificity of 100 % (70/70) for major infarcts (>9 mm² in-plane) and a sensitivity of up to 94 % (121/129) for detecting subacute microembolic lesions. No susceptibility artifacts were noticed in STEAM-DWI.

Compared to standard [[EPI-DWI]], [[STEAM-DWI]] offers a more robust alternative for diagnosing [[subacute]] [[stroke]]s in areas affected by [[susceptibility artifact]]s
((Müller SJ, Khadhraoui E, Kube JMV, Langer P, Riedel CH, Voit D, Ernst M, Frahm J. Diagnostic value of diffusion-weighted [[STEAM]]-[[MRI]] in [[ischemic stroke]]. Eur J Radiol. 2021 Mar 26;139:109677. doi: 10.1016/j.ejrad.2021.109677. Epub ahead of print. PMID: 33813283.))