BACKGROUND:A revised classification of cerebellar infarctions (CI) may uncover unrecognized associations with etiologic stroke subtypes. We hypothesized that obliquely oriented small cortical cerebellar infarction (SCCI) representing end zone infarctions on MRI would be associated with cardiac embolism.METHODS:We retrospectively analyzed consecutive stroke patients recruited between January-December 2016 in our center. Analyzed baseline characteristics: sex, age, cardiovascular risk factors, history of stroke or atrial fibrillation (AF). TOAST classification was used for determining stroke subtype. Acute infarction location (anterior/posterior/mixed anterior-posterior circulation), acute uni- or multiterritorial infarction, and acute or chronic CI/SCCI/non-SCCI were assessed by MRI, and vertebrobasilar stenosis/occlusion by vessel imaging. Pre-specified analysis was also performed in patients without known high cardioembolic risk (known AF history or acute multiterritorial infarction).RESULTS:We included 452 patients (CI in 154, isolated SCCI in 55, isolated non-SCCI in 50, and mixed SCCI/non-SCCI in 49). Both SCCI and non-SCCI were associated with AF history (SCCI, p = 0.021; non-SCCI, p = 0.004), additional acute posterior circulation infarction (p < 0.001 both CI-subtypes), multiterritorial infarctions (SCCI, p = 0.003; non-SCCI, p < 0.001) and cardioembolic more frequent than large-artery atherosclerosis origin (p < 0.001 for both CI-subtypes). SCCI was associated with older age (p < 0.001), whereas non-SCCI was associated with stroke history (p = 0.036) and vertebrobasilar stenosis/occlusion (p = 0.002). SCCI were older (p = 0.046) than non-SCCI patients, had less frequently prior stroke (p < 0.001), and more frequent cardioembolic infarction (p = 0.025). In patients without known high cardioembolic risk (n = 348), SCCI was strongly associated with subsequent cardioembolism diagnosis (OR 3.00 [CI 1.58-5.73, p < 0.001]). No such association was present in non-SCCI.CONCLUSIONS:Acute or chronic SCCI are strongly associated with a cardioembolic origin.