Acute Ischemic Injury on Diffusion-Weighted Magnetic Resonance Imaging after Poor Grade Subarachnoid Hemorrhage

Abstract

Admission DWI demonstrates multifocal areas of acute ischemic injury in poor grade SAH patients. These ischemic lesions may be related to transient intracranial circulatory arrest, acute vasoconstriction, microcirculatory disturbances, or decreased cerebral perfusion from neurogenic cardiac dysfunction. Ischemic brain injury in poor grade SAH may be a feasible target for acute resuscitation strategies.

Ischemic Brain Injury After Intracerebral Hemorrhage

“…23 The occurrence of DWI lesions, remote from the primary site of injury and delayed from the ictus, has been described in other types of brain injury including ischemic stroke, 24 transient ischemic attack, 25 and subarachnoid hemorrhage. 26 Its recent application in ICH suggests that remote ischemic lesions are found in approximately 25% of patients. 10,[27][28][29][30][31] The lesions are typically subcortical, often multiple or bilateral, and very small ( Figure 1).…”

Evolution of diffusion tensor imaging parameters after acute subarachnoid haemorrhage: a prospective cohort study

“…Involvement of the cerebellum in ischemic lesions secondary to DCI has been described in a few studies [29][30][31], affecting up to 20% of patients [32]. However, DTI changes observed the cerebellum of patients with SAH do not appear to be related the location of the ruptured aneurysm and more probably reflect a global parenchymal insult.…”

Early Prediction of Delayed Ischemia and Functional Outcome in Acute Subarachnoid Hemorrhage

“…The cerebellum is particularly vulnerable to several types of insults. Involvement of the cerebellum in ischemic lesions secondary to DCI has been described in a few studies, [34][35][36] affecting ≤20% of patients. 37 Because DTI parameters have increased sensitivity to microstructural changes 29 they might be able to demonstrate injury, not visible in conventional MRI sequences.…”

“…33 Therefore, in patients with SAH, we would expect to observe a reduction in ADC secondary to vasospasm and ischemia. Accordingly, acute ischemia after SAH is detectable in MRI studies using DWI and is proportional to neurological impairment on admission 12,34 and functional outcome in the long term. 35 Besides, increased ADC values were described at a subacute stage of SAH, thought to be caused by vasogenic edema.…”