No abstract

SUMMARY:Our aim was to review the etiologic background of isolated acute nontraumatic cSAH. While SAH located in the basal cisterns originates from a ruptured aneurysm in approximately 85% of cases, a broad spectrum of vascular and even nonvascular pathologies can cause acute nontraumatic SAH along the convexity. Arteriovenous malformations or fistulas, cortical venous and/or dural sinus thrombosis, and distal and proximal arteriopathies (RCVS, vasculitides, mycotic aneurysms, Moyamoya, or severe atherosclerotic carotid disease) should be sought by noninvasive imaging methods or/and conventional angiography. Additionally, PRES may also be a source of acute cSAH. In elderly patients, cSAH might be attributed to CAA if numerous hemorrhages are demonstrated by GRE T2 images. Finally, cSAH is rarely observed in nonvascular disorders, such as abscess and primitive or secondary brain tumors.ABBREVIATIONS: CAA ϭ cerebral amyloid angiopathy; cSAH ϭ cortical subarachnoid hemorrhage; CTA ϭ CT angiography; CTV ϭ CT venography; CVT ϭ cerebral venous thrombosis; DSA ϭ digital subtraction angiography; DWI ϭ diffusion-weighted imaging; FLAIR ϭ fluid-attenuated inversion recovery; Gd ϭ gadolinium; GRE T2 ϭ gradient echo T2-weighted imaging; MRA ϭ MR angiography; MRV ϭ MR venography; PRES ϭ posterior reversible encephalopathy syndrome; RCVS ϭ reversible cerebral vasoconstriction syndrome; SAH ϭ subarachnoid hemorrhage; SWI ϭ susceptibility-weighted imaging; TIA ϭ transient ischemic attack; TOF ϭ time of flight N ontraumatic (spontaneous) SAH arises in approximately 85% of cases from rupture of a saccular aneurysm at the base of the brain. Nonaneurysmal perimesencephalic hemorrhages account for another 10%.

Background: The pathogenesis of moyamoya disease (MMD) is still unknown. The detection of inflammatory molecules such as cytokines, chemokines and growth factors in MMD patients' biological fluids supports the hypothesis that an abnormal angiogenesis is implicated in MMD pathogenesis. However, it is unclear whether these anomalies are the consequences of the disease or rather causal factors as well as these mechanisms remain insufficient to explain the pathophysiology of MMD. The presence of a family history in about 9-15% of Asian patients, the highly variable incidence rate between different ethnic and sex groups and the age of onset support the role of genetic factors in MMD pathogenesis. However, although some genetic loci have been associated with MMD, few of them have been replicated in independent series. Recently, RNF213 gene was shown to be strongly associated with MMD occurrence with a founder effect in East Asian patients. However, the mechanisms leading from RNF213 mutations to MMD clinical features are still unknown. Summary: The research on pathogenic mechanism of MMD is in its infancy. MMD is probably a complex and heterogeneous disorder, including different phenotypes and genotypes, in which more than a single factor is implicated. Key Message: Since the diagnosis of MMD is rapidly increasing worldwide, the development of more efficient stratifying risk systems, including both clinical but also biological drivers became imperative to improve our ability of predict prognosis and to develop mechanism-tailored interventions.

Background and Purpose: Mechanical thrombectomy (MT) is the recommended treatment for acute ischemic stroke caused by anterior circulation large vessel occlusion. However, despite a high rate of reperfusion, the clinical response to successful MT remains highly variable in the early time window where optimal imaging selection criteria have not been established. We hypothesize that the baseline perfusion imaging profile may help forecast the clinical response to MT in this setting. Methods: We conducted a prospective multicenter cohort study of patients with large vessel occlusion–related acute ischemic stroke treated by MT within 6 hours. Treatment decisions and the modified Rankin Scale evaluation at 3 months were performed blinded to the results of baseline perfusion imaging. Study groups were defined a posteriori based on predefined imaging profiles: target mismatch (TMM; core volume <70 mL/mismatch ratio >1.2 and mismatch volume >10 mL) versus no TMM or mismatch (MM; mismatch ratio >1.2 and volume >10 mL) versus no MM. Functional recovery (modified Rankin Scale, 0–2) at 3 months was compared based on imaging profile at baseline and whether reperfusion (modified Thrombolysis in Cerebral Infarction 2bc3) was achieved. Results: Two hundred eighteen patients (mean age, 71±15 years; median National Institutes of Health Stroke Scale score, 17 [interquartile range, 12–21]) were enrolled. Perfusion imaging profiles were 71% TMM and 82% MM. The rate of functional recovery was 54% overall. Both TMM and MM profiles were independently associated with a higher rate on functional recovery at 3 months Adjusted odds ratios were 3.3 (95% CI, 1.4–7.9) for TMM and 5.9 (95% CI, 1.8–19.6) for MM. Reperfusion (modified Thrombolysis in Cerebral Infarction 2bc3) was achieved in 86% and was more frequent in TMM and MM patients. Reperfusion was associated with a higher rate of functional recovery in MM and TMM patients but not among those with no MM. Conclusions: In this cohort study, about 80% of the patients with a large vessel occlusion–related acute ischemic stroke had evidence of penumbra, regardless of infarction volume. Perfusion imaging profiles predict the clinical response to MT.

Our findings suggest that CAA could be a common cause of cSAH in the elderly with a fairly uniform clinical presentation. In addition to prior cortical bleeding (ICH, MBs), most patients from the present series had evidence of focal cortical hemosiderosis likely corresponding with prior unrecognized cSAH and suggesting that cSAH was a recurrent event.