Interobserver Reliability on Intravoxel Incoherent Motion Imaging in Patients with Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Noninvasive perfusion-weighted imaging with short scanning time could be advantageous in order to determine presumed penumbral regions and subsequent treatment strategy for acute ischemic stroke (AIS). Our aim was to evaluate interobserver agreement and the clinical utility of intravoxel incoherent motion MR imaging in patients with acute ischemic stroke. MATERIALS AND METHODS: We retrospectively studied 29 patients with AIS (17 men, 12 women; mean age, 75.2 [SD, 12.0 ] years; median, 77 years). Each patient underwent intravoxel incoherent motion MR imaging using a 1.5T MR imaging scanner. Diffusion-sensitizing gradients were applied sequentially in the x, y, and z directions with 6 different b-values (0, 50, 100, 150, 200, and 1000 seconds/mm2). From the intravoxel incoherent motion MR imaging data, diffusion coefficient, perfusion fraction, and pseudodiffusion coefficient maps were obtained using a 2-step fitting algorithm based on the Levenberg-Marquardt method. The presence of decreases in the intravoxel incoherent motion perfusion fraction and pseudodiffusion coefficient values compared with the contralateral normal-appearing brain was graded on a 2-point scale by 2 independent neuroradiologists. Interobserver agreement on the rating scale was evaluated using the κ statistic. Clinical characteristics of patients with a nondecreased intravoxel incoherent motion perfusion fraction and/or pseudodiffusion coefficient rated by the 2 observers were also assessed. RESULTS: Interobserver agreement was shown for the intravoxel incoherent motion perfusion fraction (κ = 0.854) and pseudodiffusion coefficient (κ = 0.789) maps, which indicated almost perfect and substantial agreement, respectively. Patients with a nondecreased intravoxel incoherent motion perfusion fraction tended to show recanalization of the occluded intracranial arteries more frequently than patients with a decreased intravoxel incoherent motion perfusion fraction. CONCLUSIONS: Intravoxel incoherent motion MR imaging could be performed in < 1 minute in addition to routine DWI. Intravoxel incoherent motion parameters noninvasively provide feasible, qualitative perfusion-related information for assessing patients with acute ischemic stroke.

The impact of predisposing factors on long-term outcome after stroke in diabetic patients: the Fukuoka Stroke Registry.

BACKGROUND AND PURPOSE: Although stroke patients with diabetes mellitus have a poor prognosis, the prognostic factors of patients with diabetes mellitus have not been adequately studied. The aim of this study was to determine the predisposing factors for outcome 1 year after stroke in diabetic patients. METHODS: Patients' characteristics, findings on admission and outcome 1 year after first ischaemic stroke were prospectively investigated in 452 consecutive patients with diabetes mellitus (305 males, 147 females; 69 ±â€…10 years old). A poor outcome was defined as a modified Rankin Scale (mRS) score ≥ 2, 1 year after stroke onset. RESULTS: There were 286 patients with a good outcome (mRS score ≤ 1) and 166 with a poor outcome (mRS score ≥ 2). On multivariate logistic regression analysis, age [odds ratio (OR) 1.06, 95% confidence interval (CI) 1.03-1.10, P < 0.001, per 1-year increase], National Institutes of Health Stroke Scale (NIHSS) score on admission (OR 1.21, 95% CI 1.11-1.32, P < 0.001, per 1-point increase), diabetic nephropathy (OR 1.93, 95% CI 1.02-3.65, P = 0.044) and hemoglobin A1c (HbA1c; OR 1.27, 95% CI 1.07-1.51, P = 0.007, per 1% increase) were independently related to poor outcome (mRS score ≥ 2) 1 year after the onset of the first stroke in diabetic patients. CONCLUSIONS: In stroke patients with diabetes mellitus, age, NIHSS score on admission, diabetic nephropathy and HbA1c were independently associated with a poor outcome 1 year after the first ischaemic stroke.