Small vessel disease contributions to acute delirium: a pilot feasibility MRI study

Abstract

Background and aims Delirium carries an eight-fold risk of future dementia. Small vessel disease (SVD), best seen on magnetic resonance imaging (MRI), increases delirium risk, yet delirium is understudied in MRI research. We aimed to determine MRI feasibility, tolerability, image usability and prevalence of SVD lesions in delirium. Methods This case–control feasibility study performed MRI (3D T1/T2-weighted), fluid-attenuated inversion recovery, susceptibility-weighted and diffusion-weighted imaging (DWI) on 20 medical inpatients >65 years: 10 with delirium ≥3 weeks and 10 without delirium, matched for vascular risk, Clinical Frailty Scale (CFS) and cognition. We excluded acute stroke, agitation necessitating sedation, mobility assistance of >2 and MRI contraindications. We measured scan duration, tolerability, image usability, acute infarcts and SVD features. Six months later, we recorded CFS and cognitive diagnoses. Results Mean age was 83.5 years (delirium 78.7 vs non-delirium 88.4); 13/20 were female; 17/20 had premorbid cognitive decline/impairment or dementia. Acquisition took mean 26.8 min. MRI was well tolerated in 16/20 (7/10 in delirium arm; 9/10 in non-delirium arm). Also, 4/20 had early scan termination, but 20/20 had clinically interpretable images. We detected DWI-hyperintense lesions in 3/10 (30%) with delirium (2/10 small subcortical and 1/10 cortical) and in 3/10 (30%) without delirium (2/10 small subcortical; 1/10 cortical). Mean white matter hyperintensity Fazekas score was 6 in delirium versus 4.5 without. Conclusions MRI is feasible, usable and tolerable in delirium, and we detected DWI-hyperintense lesions in one-third of all study participants, regardless of delirium status. This study indicates acute vascular contributions, including SVD, to both delirium- and non-delirium–related presentations, supporting the need for larger studies.