Cerebral Blood Flow–Derived Myogenic Dynamics Reveal Impaired Postischemic Cerebrovascular Recovery in Experimental Stroke

Background Restoration of cerebral blood flow (CBF) after ischemic stroke does not necessarily indicate recovery of cerebrovascular regulation. We tested whether myogenic‐band dynamics derived directly from CBF signals provide information beyond mean perfusion during cerebral ischemia and after acute stroke. Methods Transient focal cerebral ischemia was induced in 29 Sprague–Dawley rats using middle cerebral artery occlusion/reperfusion. Bilateral laser‐Doppler flowmetry (LDF)‐derived CBF signals were decomposed using empirical mode decomposition and Hilbert transform, and myogenic‐band activity (0.15–0.4 Hz) was quantified by absolute and relative power. Cross‐validated logistic regression models were used to evaluate whether myogenic‐band power provided discriminative information beyond mean CBF alone. Results Ipsilateral mean CBF fell from 73.5±51.8 p.u. at baseline to 52.2±38.0 p.u. during late ischemia (P=0.0088), then increased to 126.6±91.5 p.u. after 3 hours of reperfusion (P=0.0050 versus baseline). Relative myogenic‐band power decreased from 37.43±14.65% to 13.35±7.51% during ischemia (P<0.0001) and remained below baseline after reperfusion (20.74±12.02%, P=0.00033 versus baseline); contralateral relative power was comparatively preserved. Combining mean CBF and myogenic‐band power improved discrimination of baseline from late ischemia (AUC, 0.99 versus 0.70 for mean CBF alone) and late reperfusion (AUC, 0.88 versus 0.70). Conclusions Frequency‐specific analysis of LDF‐derived CBF reveals persistent, lateralized abnormalities in myogenic‐band dynamics that are not captured by mean perfusion alone. The persistence of depressed myogenic activity despite restored or elevated mean CBF demonstrates incomplete recovery of frequency‐specific oscillatory dynamics after reperfusion. These findings support myogenic‐band power as a potential functional measure of persistent postischemic cerebrovascular dysfunction.