Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke research. Export

@article{citeulike:5429389, abstract = {BACKGROUND AND PURPOSE: The measurement of ischemic lesion volume on diffusion- (DWI) and perfusion-weighted MRI (PWI) is examiner dependent. We sought to quantify the variance imposed by measurement error in DWI and PWI lesion volume measurements in ischemic stroke. METHODS: Fifty-eight consecutive patients with DWI and PWI within 12 hours of symptom onset and follow-up MRI on >or= day-5 were studied. Two radiologists blinded to each other measured lesion volumes by manual outlining on each image. Interexaminer reliability was evaluated by intraclass correlation coefficients (ICC) and relative paired difference or RPD (ratio of difference between 2 measurements to their mean). The ratio of between-examiner variability to between-subject variability (variance ratio) was calculated for each imaging parameter. RESULTS: The correlation (ICC) between examiners ranged from 0.93 to 0.99. The median RPD was 10.0\% for DWI, 14.1\% for mean transit time, 18.9\% for cerebral blood flow, 21.0\% for cerebral blood volume, 16.8\% for DWI/MTT mismatch, and 6.3\% for chronic T2-weighted images. There was negative correlation between RPD and lesion volume in all but chronic T2-weighted images. The variance ratio ranged between 0.02 and 0.10. CONCLUSIONS: Despite high correlation between volume measurements of abnormal regions on DWI and PWI by different examiners, substantial differences in individual measurements can still occur. The magnitude of variance from measurement error is primarily determined by the type of imaging and lesion volume. Minimizing this source of variance will better enable imaging to deliver on its promise of smaller sample size.}, author = {Ay, Hakan and Arsava, E. Murat and Vangel, Mark and Oner, Banu and Zhu, Mingwang and Wu, Ona and Singhal, Aneesh and Koroshetz, Walter J. and Sorensen, A. Gregory}, citeulike-article-id = {5429389}, citeulike-linkout-0 = {http://dx.doi.org/10.1161/STROKEAHA.107.502104}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18292377}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18292377}, doi = {10.1161/STROKEAHA.107.502104}, issn = {1524-4628}, journal = {Stroke; a journal of cerebral circulation}, keywords = {brain, dwi, human, imaging, lesion, mri, pwi, reliability, stroke, volumetry}, month = {April}, number = {4}, pages = {1171--1176}, posted-at = {2009-08-12 20:55:38}, priority = {2}, title = {Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke research.}, url = {http://dx.doi.org/10.1161/STROKEAHA.107.502104}, volume = {39}, year = {2008} }

TY - JOUR ID - citeulike:5429389 L3 - citeulike-article-id:5429389 N2 - BACKGROUND AND PURPOSE: The measurement of ischemic lesion volume on diffusion- (DWI) and perfusion-weighted MRI (PWI) is examiner dependent. We sought to quantify the variance imposed by measurement error in DWI and PWI lesion volume measurements in ischemic stroke. METHODS: Fifty-eight consecutive patients with DWI and PWI within 12 hours of symptom onset and follow-up MRI on >or= day-5 were studied. Two radiologists blinded to each other measured lesion volumes by manual outlining on each image. Interexaminer reliability was evaluated by intraclass correlation coefficients (ICC) and relative paired difference or RPD (ratio of difference between 2 measurements to their mean). The ratio of between-examiner variability to between-subject variability (variance ratio) was calculated for each imaging parameter. RESULTS: The correlation (ICC) between examiners ranged from 0.93 to 0.99. The median RPD was 10.0% for DWI, 14.1% for mean transit time, 18.9% for cerebral blood flow, 21.0% for cerebral blood volume, 16.8% for DWI/MTT mismatch, and 6.3% for chronic T2-weighted images. There was negative correlation between RPD and lesion volume in all but chronic T2-weighted images. The variance ratio ranged between 0.02 and 0.10. CONCLUSIONS: Despite high correlation between volume measurements of abnormal regions on DWI and PWI by different examiners, substantial differences in individual measurements can still occur. The magnitude of variance from measurement error is primarily determined by the type of imaging and lesion volume. Minimizing this source of variance will better enable imaging to deliver on its promise of smaller sample size. IS - 4 JF - Stroke; a journal of cerebral circulation SN - 1524-4628 EP - 1176 TI - Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke research. VL - 39 SP - 1171 KW - brain KW - dwi KW - human KW - imaging KW - lesion KW - mri KW - pwi KW - reliability KW - stroke KW - volumetry AU - Ay, Hakan AU - Arsava, Murat AU - Vangel, Mark AU - Oner, Banu AU - Zhu, Mingwang AU - Wu, Ona AU - Singhal, Aneesh AU - Koroshetz, Walter AU - Sorensen, Gregory PY - 2008/04// UR - http://dx.doi.org/10.1161/STROKEAHA.107.502104 ER -