Intra- and interrater reliability of ischemic lesion volume measurements on diffusion-weighted, mean transit time and fluid-attenuated inversion recovery MRI.
OBJECTIVE
We investigated the intra- and interrater reliability of ischemic lesion volumes measurements assessed by different MRI sequences at various times from onset.


METHODS
Ischemic lesion volumes were measured for intrarater reliability using diffusion-weighted (DWI), mean transit time (MTT) perfusion and fluid-attenuated inversion recovery (FLAIR) MRI at chronic (>3 days from stroke onset) time points. A single intrarater reader, blind to clinical information and time point, repeated the volume measurements on two occasions separated by at least 1 week. Interrater reliability was also obtained in the second set of patients using acute DWI, MTT and chronic FLAIR MRI. Four blinded readers performed these volume measurements. Average deviations across repeat measurements per lesion and differences between sample means between the two measurements were calculated globally, ie, across all sequences and time points, and per reader type for each sequence at each time point.


RESULTS
There was good concordance of the mean sample volumes of the 2 intrarater readings (deviations were <4% and 2 mL globally, <2% and 2 mL for DWI, <6% and 7 mL for MTT, and <2% and 1 mL for FLAIR). There was also good concordance of the interrater readings (<5% and 2 mL globally).


CONCLUSIONS
Repeat measurements of stroke lesion volumes show excellent intra- and interrater concordance for DWI, MTT and FLAIR at acute through chronic time points.
Luby
Marie
M
Section on Stroke Diagnostics and Therapeutics, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Rm. B1D733, MSC 1063, Bethesda, MD 20892, USA. lubym@ninds.nih.gov
Bykowski
Julie L
JL
Schellinger
Peter D
PD
Merino
José G
JG
Warach
Steven
S
D002545:Brain Ischemia / Q000453:epidemiology / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards; D011446:Prospective Studies; D013997:Time Factors