Influence of Stroke Infarct Location on Functional Outcome Measured by the Modified Rankin Scale

Abstract

P rognosis of functional outcome after ischemic stroke is influenced by a variety of factors already assessable in the acute phase and within the first days after symptom onset. In clinical trials, stroke outcome is most commonly rated by the modified Rankin Scale (mRS) 1 because of the validity and rapid application of this rating scale and its ability to discriminate clinically relevant levels of disability and recovery.2-4 Brain imaging in the early phase after stroke onset provides valuable information related to individual functional recovery. 5,6 In particular, structural MRI identifies injured brain regions and allows for assessment of extent and location, both known to influence and predict functional outcome measured by the mRS.3 However, infarct volume from early MRI correlates only moderately with the mRS at later time points, 7,8 indicating that additional factors, such as lesion location, influence functional outcome. It is therefore of major interest to elucidate the relationship between early lesion patterns and functional impairment in the later course of stroke.Clinical impact of lesion locations can be inferred from voxel-based lesion symptom mapping (VLSM). This statistical method examines effects of brain lesions on behavioral scores on a voxel-by-voxel base. Therefore, a statistical test is conducted for each voxel to detect differences in a behavioral score based on the presence or absence of injury.9 VLSM produces statistical results that map structural lesions to a behavioral scale. In patients with chronic stroke, it has been Background and Purpose-In the early days after ischemic stroke, information on structural brain damage from MRI supports prognosis of functional outcome. It is rated widely by the modified Rankin Scale that correlates only moderately with lesion volume. We therefore aimed to elucidate the influence of lesion location from early MRI (days 2-3) on functional outcome after 1 month using voxel-based lesion symptom mapping. Methods-We analyzed clinical and MRI data of patients from a prospective European multicenter stroke imaging study (I-KNOW). Lesions were delineated on fluid-attenuated inversion recovery images on days 2 to 3 after stroke onset. We generated statistic maps of lesion contribution related to clinical outcome (modified Rankin Scale) after 1 month using voxel-based lesion symptom mapping. Results-Lesion maps of 101 patients with middle cerebral artery infarctions were included for analysis (right-sided stroke, 47%). Mean age was 67 years, median admission National Institutes of Health Stroke Scale was 11. Mean infarct volumes were comparable between both sides (left, 37.5 mL; right, 43.7 mL). Voxel-based lesion symptom mapping revealed areas with high influence on higher modified Rankin Scale in regions involving the corona radiata, internal capsule, and insula. In addition, asymmetrically distributed impact patterns were found involving the right inferior temporal gyrus and left superior temporal gyrus. Conclusions-In this group of patients with strok...

Ipsilateral Prominent Thalamostriate Vein on Susceptibility-Weighted Imaging Predicts Poor Outcome after Intravenous Thrombolysis in Acute Ischemic Stroke

“…The TSV mainly drains the basal ganglia and thalamus, which play important roles in motor control and motor learning, [14][15][16] and these functions have a strong influence on the mRS score. 17 Lesions within the territory draining to the SV, such as the septum pellucidum, rostral corpus callosum, and white matter of the frontal lobe, may have less impact on the mRS score. The ICV receives tributaries from subcortical, periventricular structures and the choroid plexus within the lateral ventricle, and this extensive venous drainage territory may dilute the relationship between critical functions and changes in venous signal.…”

Reperfusion Within 6 Hours Outperforms Recanalization in Predicting Penumbra Salvage, Lesion Growth, Final Infarct, and Clinical Outcome

“…Several previously published reports are based on this cohort. [12][13][14][15] Inclusion criteria for I-KNOW were (1) NIHSS ≥4; (2) diffusionweighted imaging (DWI) and perfusion-weighted imaging (PWI) consistent with an acute anterior circulation ischemic stroke; and (3) admission MRI completed within 6 hours for patients treated with intravenous tPA, or within 12 hours for those managed without tPA. Patients with lacunar or posterior circulation stroke, unknown time of onset or intracerebral hemorrhage were excluded.…”

Cerebral regions preserved by successful endovascular recanalization of acute M1 segment occlusions: a voxel based analysis

“…24,25 A voxelbased analysis of consecutive patients with stroke also showed that infarction of corona radiata, internal capsule and insula was associated with higher mRS scores at 1-month follow-up. 26 The selective vulnerability of central MCA territory, striatum and adjacent white matter is attributed to the sole blood supply from lateral lenticulostriate arterial branches of MCA without any other collateral supply. 27 It is likely that the vascular supply to the insula reflects the confluence of bulk flow through the MCA divisions, clot location and collateral flow.…”