Imaging patterns and prognosis of proximal and distal small subcortical infarcts

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.

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.

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.

d-SSI and p-SSI have different imaging and prognostic characteristics that may suggest a distinct etiological origin and possibly different therapeutic approach.