As the corticospinal tracts cross the lenticulostriate artery (LSA) territory at the posterior segment, we hypothesized that posteriorly located infarctions of the LSA may be associated with progressive motor deficits. We prospectively studied 519 consecutive patients with LSA infarctions who entered our hospital within 24 h after onset. We categorized patients into two groups in terms of progress: no progress and progress. Progress was defined as worsening by 1 point or more in the National Institutes of Health Stroke Scale (NIHSS), some of which recovered afterward or thoroughly progressed. LSA infarctions on the first DWI were divided into proximal type and distal (group 1) type. The proximal type was further divided into anterior (group 2), intermediate (group 3) and posterior (group 4) type according to the middle point of antero-posterior diameter of the lateral ventricle. There were 109 patients who showed progress that accounted for 21.0% of all patients. The number of patients who progressed is as follows: distal type 65 (23.8%), anterior type 31 (36.0%), intermediate type 26 (56.5%) and posterior type 97 (85.0%). The Cochran-Armitage test showed a significant increase through group 1 to group 4 (p < 0.0001). Independent predictive factors for progress were male (OR 0.57, p = 0.0107), higher NIHSS on admission (≥4) (OR 3.02, p < 0.0001), intermediate proximal type (OR 3.3, p = 0.0007) and posterior proximal type (OR 16.4, p < 0.0001). The more posterior the infarct location, the more frequent was the progress that occurred, probably due to the anatomical fact that corticospinal tracts crossed the LSA territory at the posterosuperior quadrant.
Keywords: Branch atheromatous disease; Corticospinal tract; Lenticulostriate artery; Posterior corona radiata; Progressive motor deficits.