Imaging patterns and prognosis of proximal and distal small subcortical infarcts

Introduction: Small subcortical infarcts (SSI) are one of the hallmarks of cerebral small vessel disease and have been classified in two different imaging patterns: proximal-SSI (p-SSI) and distal-SSI (d-SSI), according to the shape, size and location to the parent artery. We aimed to investigate imaging and prognosis differences between p-SSI and d-SSI. Methods: We retrospectively reviewed records of consecutive patients with SSI admitted at two Stroke Units. We assessed location, shape and axial diameter of p-SSI and d-SSI with computed tomography (CT) and/or magnetic resonance (MR) imaging blinded to clinical data. Outcomes were: Early Neurological Deterioration (END), length of hospital stay, rehabilitation after discharge and functional status at 3 months assessed with modified Rankin Scale (mRS). We assessed independent associations between type of subcortical stroke and outcomes with logistic and ordinal regression analysis. Results: We included 292 patients, mean (+ -SD) age 67.42 (+ -12.41) years, 205 (70%) males, median (IQR) NIHSS = 4 (2–5); END occurred in 57 (20%) patients. Compared with d-SSI, p-SSI was associated with non-rounded shape (82%vs 65%,p = 0.005), lesion diameter > 15 mm (34% vs 10%,p < 0.001), infratentorial location (39% vs 23%,p = 0.005), absence of white matter changes (22% vs 12%,p = 0.035). END occurred more frequently in p-SSI (44% vs 10%,p < 0.001; OR = 7.23;95%CI = 3.73–14.03). In p-SSI, length of hospital stay was more frequently longer than six days (58% vs 40%,p = 0.005; OR = 1.78;95%CI = 1.04–3.07) and a shift towards worse mRS (cOR = 2.47;95%CI = 1.46–4.18) was observed. Conclusions: d-SSI and p-SSI have different imaging and prognostic characteristics that may suggest a distinct etiological origin and possibly different therapeutic approach.