Perfusion Defects and Collateral Flow Patterns in Acute Small Subcortical Infarction: a 4D Dynamic MRI Study

Abstract

The hemodynamic changes of acute small subcortical infarction (SSI) are not well understood. We evaluate the hemodynamic changes and collaterals in acute SSI using perfusion magnetic resonance imaging (MRI). A total of 103 patients with acute SSI in penetrating artery territories were recruited and underwent MRI within 24 h of stroke onset. Using 4D dynamic perfusion MRI, they were divided into three patterns: 25 (24%) with normal perfusion, 31 (30%) with compensated perfusion, and 47 (46%) with hypoperfusion. The development of anterograde or retrograde collaterals was also evaluated. Patients with hypoperfusion pattern had the highest rate of early neurological deterioration (32%, p = 0.007), the largest initial and final infarction volumes (p < 0.001 and p = 0.029), the lowest relative cerebral blood flow (0.63, p < 0.001), and the lowest rate of anterograde and retrograde collaterals (19%, p < 0.001; 66%, p = 0.002). The anterograde collaterals were associated with higher relative cerebral blood volume (0.91 vs. 0.77; p = 0.024) and a higher rate of deep cerebral microbleeds (48 vs. 21%; p = 0.028), whereas retrograde collaterals were associated with higher systolic and diastolic blood pressure (p = 0.031 and 0.020), smaller initial infarction volume (0.81 vs. 1.34 ml, p = 0.031), and a higher rate of lobar cerebral microbleeds (30 vs. 0%; p = 0.013). Both anterograde and retrograde collaterals may play a critical role in maintaining cerebral perfusion and can have an impact on patient clinical outcomes. Further studies are warranted to verify these findings and to investigate effective treatments.

Association of compromised cerebral perfusion with lenticulostriate artery impairments in the subacute phase of branch atheromatous disease

“…A recent perfusion MRI study showed that BAD patients were associated with fewer normal perfusion patterns, but BAD in that study was diagnosed based only on infarct sites on conventional brain MRI. 4 BAD involving persistent perfusion defects has been attributed to atherothrombotic blockage of penetrating arteries with less autoregulation, or to insufficient collateral blood flow from adjacent vascular territories, which is often concomitant with larger lesion size. 2 , 28 , 29 We also showed that patients with BAD were more prone to END and had a worse 3-month functional outcome, consistent with previous studies.…”

The Potential Impact of Neuroimaging and Translational Research on the Clinical Management of Lacunar Stroke

“…However, the fluctuating insufficiency of a residual blood flow compensation through collateral vessels from nearby perforating arteries would also be consistent with the clinical stuttering presentation. Although perforating artery branches are not directly visible in vivo using conventional imaging, three perfusion studies, one based on CT perfusion [28] and two on MRI perfusion [45,46], provided similar results of indirect evidence of hemodynamical compensation, through retrograde blood flow filling centripetally the ischemic regions that evolved into a RSSI, suggesting the presence of microscopic collateral supply by a capillary network. In few cases, the ischemic area showed an early and anterograde filling, corresponding to normal or increased perfusion, indicating the patency of the perforating artery during image acquisition, consistent with recanalization, suggesting an embolic origin of the occlusion in a minority of patients [28].…”

PCSK9 inhibition in patients with acute stroke and symptomatic intracranial atherosclerosis: protocol for a prospective, randomised, open-label, blinded end-point trial with vessel-wall MR imaging

“…The MR angiography used 3-D time of flight (TR/TE=20/3.6 ms and 0.8 mm thickness) covering the extracranial carotid artery and the circle of Willis. 26 …”

“…The imaging sequences and parameters are as follows:, T2-weighted TSE imaging (repetition time (TR)/echo time (TE)=2800/90 ms, 245×320 acquisition matrix, 4.0 mm slice thickness and 28 slices), FLAIR imaging (TR/TE=8000/93 ms, inversion time=2400 ms, 320×256 acquisition matrix, 4.0 mm slice thickness, 28 slices and 230×320 mm field of view (FOV)) and DWI (TR/TE=8400/90, 160×160 acquisition matrix, 4.0 mm slice thickness, 28 slices, b-factor=1300 and 230×230 mm field of view (FOV)). The MR angiography used 3-D time of flight (TR/TE=20/3.6 ms and 0.8 mm thickness) covering the extracranial carotid artery and the circle of Willis 26…”