D* from diffusion MRI reveals a correspondence between ventricular cerebrospinal fluid volume and flow in the ischemic rodent model.

Quantitative measurement of cerebrospinal fluid (CSF) flow and volume and longitudinal monitoring of CSF dynamics provide insights into the compensatory characteristics of post-stroke CSF. In this study, we compared the MRI pseudo-diffusion index (D*) of live and sacrificed rat brains to confirm the effect of ventricular CSF flow on diffusion signals. We observed the relationship between the CSF peak velocities and D* through Monte Carlo (MC) simulations to further understand the source of D* contrast. We also determined the dominant CSF flow using D* in three directions. Finally, we investigated the dynamic evolutions of ventricular CSF flow and volume in a stroke rat model (n = 8) from preoperative to up to 45 days after surgery and determined the correlation between ventricular CSF volume and flow. MC simulations showed a strong positive correlation between the CSF peak velocity and D* (r = 0.99). The dominant CSF flow variations in the 3D ventricle could be measured using the maximum D* map. A longitudinal positive correlation between ventricular CSF volume and D* was observed in the lateral (r = 0.74) and ventral-third (r = 0.81) ventricles, respectively. The directional D* measurements provide quantitative CSF volume and flow information, which would provide useful insights into ischemic stroke with diffusion MRI.

[Susceptibility vessel sign in subacute stroke patients with large vessel occlusion].

OBJECTIVE: To investigate the presentation of susceptibility vessel sign (SVS) in subacute stroke patients with large vessel occlusion. METHODS: We collected consecutive stroke patients who were admitted to Peking University First Hospital from December 2017 to August 2019 retrospectively. Those who had intracranial large vessel occlusion and received sensitivity weighted imaging (SWI) within 3 to 14 days after stroke onset were included in our analysis. The diagnosis of large vessel occlusion was based on magnetic resonance angiography (MRA), CT angiography (CTA) or digital subtraction angiography (DSA). The demographic information, clinical characteristics and imaging results were obtained from medical record. The occurrence rates of SVS sign were compared between stroke patients with cardioembolism (CE) and large artery atherosclerosis (LAA). In the sensitivity analysis, we performed a subgroup analysis in those patients who received SWI within 7 to 14 days after stroke onset. We also compared the occurrence rate of SVS sign between the patients with and without atrial fibrillation. RESULTS: A total of 51 patients, 19 females and 32 males, with an average age of (63.04±11.23) years were analyzed in this study. Compared with LAA group, the patients in CE group were older and more likely to have an atrial fibrillation (P < 0.05). There were no significant differences between the CE group and LAA group in gender, hypertension, diabetes, coronary heart disease, hyperlipidemia, smoking, or National Institute of Health stroke scale(NIHSS) score at admission. SVS sign was found in 30 patients. Of whom, 3 were in CE group and 27 in LAA group. The occurrence rate of SVS sign was higher in the LAA group than in the CE group significantly (65.9% vs. 30.0%, P=0.039). The subgroup analysis showed that, in the patients who received SWI examination within 7 to 14 days after stroke onset, the differences between the two groups were still statistically significant (0 vs. 72.7%, P=0.006). Another sensitivity analysis showed that, the rate of SVS in the patients with atrial fibrillation was significantly lower than those patients without atrial fibrillation (25% vs. 65.1%, P=0.043). CONCLUSION: In subacute stroke patients, the occurrence rate of SVS sign in CE group was lower than that of LAA group. The significance of SVS sign in the differentiation of stroke subtype needs further validation.

Efficacy of Early Superficial Temporal Artery-Middle Cerebral Artery Double Anastomoses for Atherosclerotic Occlusion in Patients with Progressing Stroke.

BACKGROUND: We investigated the efficacy of early superficial temporal artery-middle cerebral artery (STA-MCA) double anastomoses for patients with progressing stroke due to atherosclerotic occlusion. MATERIALS AND METHODS: Nine consecutive patients who underwent early STA-MCA double anastomoses were enrolled. All patients presented with progressing stroke despite maximal medical treatment. Cerebral blood flow in 7 patients was analyzed by single-photon emission tomography. Clinical outcomes were investigated postoperatively, and we evaluated the utility of early STA-MCA double anastomoses. RESULTS: Nine patients in the present study included those with middle cerebral artery occlusion (n = 6) and internal carotid artery occlusion (n = 3). The mean age was 58.4 years. Subjects comprised 1 female (11.1%) and 8 males (88.9%). The cause was low perfusion ischemia due to atherosclerotic occlusion with a small infarct. The mean regional cerebral blood flow (rCBF) ratio in the middle cerebral artery territory compared to the normal side was 69.6 ± 5.3%. The duration from onset to surgery was 1-8 days (median, 3.11 days). All patients underwent early STA-MCA double anastomoses, and no reperfusion-induced hemorrhage occurred. All of them slowly achieved obvious remission compared to symptoms on admission and achieved a good functional outcome. CONCLUSIONS: Early STA-MCA double anastomoses were safe and effective, and early revascularization resulted in rapid neurological improvement. We recommend this procedure for patients with progressive ischemia due to main trunk artery occlusion, when the rCBF flow ratio with the normal side was 70 ± 10%, even at the subacute stage.