Diffusion-weighted Imaging at b1000 for Identifying Intracerebral Hemorrhage: Preliminary Sensitivity, Specificity, and Inter-rater Variability Galina Keigler, MD,* Ilan Goldberg, MD,* Roni Eichel, MD,* John M. Gomori, MD,† Jose E. Cohen, MD,‡ and Ronen R. Leker, MD, FAHA* Background: Noncontrast computed tomography (NCCT) is the gold standard to detect intracerebral hemorrhage (ICH) and ischemic stroke (IS) in patients present- ing with acute focal syndromes. Diffusion-weighted magnetic resonance imaging (DW-MRI) obtained at b1000 is highly sensitive to identify acute IS but its sensitivity and specificity to detect ICH has not been systematically studied. Methods: Patients with a diagnosis of ICH on NCCT were prospectively enrolled and underwent DW-MRI at b1000. Patients with suspected ischemia and a negative NCCT served as controls. All diffusion-weighted imaging (DWI) scans were evaluated blindly by 4 experienced raters. Sensitivity, specificity, and inter-rater variability of the DWI b1000 scans for detection of ICH were determined. Results: In this preliminary pilot study, 15 patients with ICH and 17 patients with IS were included. All ICH lesions seen on NCCT showed a typical pattern on DW-MRI at b1000 with a hypo- intense core surrounded by a hyperintense rim. ICH volumes and size were similar on NCCT and MRI. All cases of IS were identified on the DWI scans but none were apparent on NCCT. The mean sensitivity and specificity of DW-MRI at b1000 for ICH were 94% and 93.5%, respectively, and the inter-rater variability for ICH detec- tion on DWI was excellent (k 5 .84). Conclusions: DW-MRI at b1000 has a diagnostic yield similar to NCCT for detecting ICH and superior to NCCT for detecting IS. Therefore, DW-MRI may be considered as the initial screening tool for imaging patients presenting with focal neurologic symptoms suggestive of stroke. Key Words: Stroke—diffusion-weighted MRI—cerebrovascular disease— intracerebral hemorrhage. Ó 2014 by National Stroke Association Noncontrast computed tomography (NCCT) is usually used as the initial imaging modality in patients presenting to the Emergency Department (ED) with acute focal neuro- logic symptoms and signs suggestive of stroke. 1 It is pri- marily useful in identifying patients with intracerebral hemorrhage (ICH) with sensitivity and specificity rates that approach 100% and may also be useful for identifying signs of early ischemic stroke (IS), although with much lower sensitivity and specificity rates. 1-4 Magnetic resonance imaging (MRI) and especially diffusion- weighted imaging (DWI) is much more sensitive and spe- cific than NCCT for the detection of early ischemia, 1-4 and it is currently recommended as a screening tool for patients with IS. Over the past decade, several studies evaluated different MRI protocols to estimate their ability to detect From the *Department of Neurology, Hadassah-Hebrew University Medical Center, Jerusalem; †Department of Radiology, Hadassah- Hebrew University Medical Center, Jerusalem; and ‡Department of Neurosurgery, Hadassah-Hebrew University Medical Center, Jerusa- lem, Israel. Received November 28, 2013; revision received January 6, 2014; accepted February 1, 2014. This study was supported by the Peritz and Chantal Scheinberg Ce- rebrovascular Research Fund and the Sol Irwin Juni Trust Fund. All authors have nothing to disclose. Address correspondence to Ronen R. Leker, MD, FAHA, Depart- ment of Neurology, Hebrew University-Hadassah Medical Center, PO Box 12000, Jerusalem 91120, Israel. E-mail: leker@hadassah.org.il. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2014.02.005 Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2014: pp 1-5 1