The “island sign” on diffusion-weighted imaging predicts early neurological deterioration in penetrating artery territory infarctions: a retrospective study

Background Early neurological deterioration (END) sometimes occurs in patients with penetrating artery territory infarction (PATI) and leads to poor prognosis. In this study, we analyzed clinical and neuroimaging characteristics of PATI, and focused on the infarct patterns on diffusion-weighted imaging (DWI). We tried to investigate whether the “island sign” pattern is associated with END. Methods We enrolled consecutive patients admitted with acute PATI within 48 h after onset from May 2020 to July 2022. They were divided into with and without the “island sign” pattern on DWI. According to infarct location, all the patients were classified into two groups: the territories of the lenticulostriate arteries (LSA) and paramedian pontine arteries (PPA). The patients in each group were further divided into two groups according to whether they developed END or not. Through analyzing the clinical and neuroimaging characteristics of the patients, we tried to identify the factors that might associated with the “island sign” pattern and the potential predictors of END within the LSA and PPA groups. Results Out of the 113 patients enrolled in this study, END was found in 17 patients (27.9%) in the LSA group and 20 patients (38.5%) in the PPA group. The “island sign” was found in 26 (23%) patients. In the multivariate analysis, the independent predictors of END in the LSA group were the “island sign” (OR 4.88 95% CI 1.03–23.2 P = 0.045) and high initial National Institute of Health Stroke Scale (NIHSS) (OR 1.79 95% CI 1.08–2.98 P = 0.024) and in the PPA group was the presence of lesions extending to the ventral pontine surface (OR 7.53 95% CI 1.75–32.37 P = 0.007). Conclusions The predictive factors for END were different in the LSA and PPA groups. The “island sign” was particularly associated with END in the LSA group.