Added value in stroke imaging: accuracy and utility of additional coronal diffusion-weighted imaging

M Baggett,D Helmy,J Chang,M Bobinski,R Assadsangabi

doi:10.1016/j.crad.2021.07.006

M Baggett, D Helmy + Show 3 more

Open Access

https://doi.org/10.1016/j.crad.2021.07.006

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Abstract

To evaluate the value of adding additional coronal diffusion-weighted imaging with the same section thickness as standard axial images to improve detection of small infarcts. Axial and coronal diffusion-weighted images (4 or 5 mm section thickness, 1 mm gap) were studied retrospectively in two rounds of data collection. During the first round, two radiologists identified sub-centimetre infarcts on only axial images during one sitting, and only coronal images during a second sitting. During the second round, the two radiologists were asked to identify infarcts on only axial images during one sitting, and on both axial and coronal images simultaneously during the second sitting. An expert reviewer determined true infarcts and artefacts. Relative contrast-to-noise ratios (rCNR) and relative mean region of interest (rROI) within each lesion were calculated. During the first round, sensitivity for infarct detection for the two radiologists was 92.7% and 100% on axial and 95.1% and 92.7% on coronal, respectively. During the second round, sensitivity improved from 88.9% to 98.1% for both radiologists (p=0.03). Specificity improved but did not reach statistical significance (p=0.06 and 0.12). False-negative and false-positive lesions had lower rCNR and rROI values. Including both axial and coronal DWI images with the same section thickness in the stroke protocol improves detection of small infarcts, which can be misdiagnosed on a single imaging plane. A second imaging plane is particularly useful for subtle infarcts, even without acquiring thin-section images.

Highlights

Several studies have addressed these issues by adding thin-section axial, sagittal, or coronal Diffusion-weighted imaging (DWI) sequences to the standard stroke protocol, with some promising results7e10; adding an additional thin-section sequence increases the overall scan time, which for critically ill patients, may further delay appropriate intervention and treatment.[9]
To the authors’ knowledge, no study has evaluated the value of adding coronal DWI to axial DWI with the same section thickness
It was hypothesised that adding a coronal DWI sequence with the same section thickness to the standard stroke MRI protocol would result in improved detection of sub-centimetre infarcts, in the posterior circulation, and that artefacts would be recognised more accurately rather than being mislabelled as acute infarct

Summary

Introduction

It was hypothesised that adding a coronal DWI sequence with the same section thickness to the standard stroke MRI protocol would result in improved detection of sub-centimetre infarcts, in the posterior circulation, and that artefacts would be recognised more accurately rather than being mislabelled as acute infarct. It was hypothesised that (1) performance on each imaging plane would be similar when given only one imaging plane, (2) performance would improve when given both imaging planes simultaneously, even without thin-section imaging, and (3) diagnostic errors would more likely occur for subtle DWI abnormalities

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