Background: Identifying whether acute stroke patients are at risk of cognitive decline could improve prognostic discussions and management. Structural computed tomography (CT) neuroimaging is routine in acute stroke, and may, identify those at risk of post-stroke dementia (PSD) or post-stroke cognitive impairment (PSCI). Aim: To systematically review the literature to identify which stroke or pre-stroke features on brain CT scans, performed at the time of stroke, are associated with PSD or PSCI. Summary of review: We searched electronic databases to December 2020. We included studies reporting acute stroke brain CT, and later diagnosis of a cognitive syndrome. We created summary estimates of size of unadjusted association between CT features and cognition. Of 9536 citations, twenty-eight studies (41 papers) were eligible (N=7078, mean age 59.8-78.6 years). Cognitive outcomes were PSD (10 studies), PSCI (17 studies), and one study analysed both. Fifteen studies (N=2952) reported data suitable for meta-analyses. White matter lesions (WML) (6 studies, N=1054, OR=2.46, 95% CI=1.25-4.84), cerebral atrophy (4 studies, N=558, OR=2.80, 95% CI=1.21-6.51), and pre-existing stroke lesions (3 studies, N=352, OR=2.38, 95% CI=1.06-5.32) were associated with PSD. WML (4 studies, N=473, OR=3.46, 95% CI=2.17-5.52) were associated with PSCI. Other CT features were either not associated with cognitive outcome, or there were insufficient data. Conclusions: Cognitive impairment following stroke is of great concern to patients and carers. Features seen on visual assessment of acute stroke CT brain scans are strongly associated with cognitive outcomes. Clinicians should consider when and how this information should be discussed with stroke survivors.

Background: Stroke survivors are at an increased risk of developing post-stroke cognitive impairment and post-stroke dementia; those at risk could be identified by brain imaging routinely performed at stroke onset. Aim: This systematic review aimed to identify features which are associated with post-stroke cognitive impairment (including dementia), on magnetic resonance imaging (MRI) performed at stroke diagnosis. Summary of review: We searched the literature from inception to January 2022 and identified 10,284 records. We included studies that performed MRI at the time of stroke (0-30 days after a stroke) and assessed cognitive outcome at least three months after stroke. We synthesised findings from 26 papers, comprising 27 stroke-populations (N=13,114, average age range=40-80 years, 19-62% female). When data were available, we pooled unadjusted (ORu) and adjusted (ORa) odds ratios. We found associations between cognitive outcomes and presence of cerebral atrophy (3 studies, N=453, ORu=2.48, 95%CI=1.15-4.62), presence of microbleeds (2 studies, N=9151, ORa=1.36, 95%CI=1.08-1.70), and increasing severity of white matter hyperintensities (3 studies, N=704, ORa=1.26, 95%CI=1.06-1.49). Increasing cerebral small vessel disease score was associated with cognitive outcome following unadjusted analysis only (2 studies, N=499, ORu=1.34, 95%CI=1.12-1.61; 3 studies, N=950, ORa=1.23, 95%CI=0.96-1.57). Associations remained after controlling for pre-stroke cognitive impairment. We did not find associations between other stroke features and cognitive outcome, or there were insufficient data. Conclusions: Acute stroke MRI features may enable healthcare professionals to identify patients at risk of post-stroke cognitive problems. However, there is still substantial uncertainty about the prognostic utility of acute MRI for this.