Jiaying (Jayne) Zhang, MD

Yoon Y, Lee DH, Kang DW, Kwon SU, and Kim JS. Single Subcortical Infarction and Atherosclerotic Plaques in the Middle Cerebral Artery: High-Resolution Magnetic Resonance Imaging Findings. Stroke. 2013

Subcortical stroke is often erroneously equated to lacunar stroke with similar pathophysiology. It is perhaps more accurate to use subcortical stroke as an entity that encompass two disease mechanisms – small perforating artery infarcts caused by native vessel lipohyalinosis/atherosclerosis, and infarction associated with parental artery disease. Given the distinction, it is important to study their differences to aid the understanding of potential distinguishable clinical characteristics that could impact treatment strategies. 

In this interesting study by Yoon et. al, the authors classified single subcortical infarctions (SSI) in the MCA territory into proximal SSI (pSSI) or distal SSI (dSSI) by their radiological appearance on MRI. pSSI extends to the surface of the MCA whereas dSSI does not. They enrolled 39 patients in total, half with pSSI and the other half with dSSI. Patients with pSSI had more number of large infarcts with higher NIHSS but less microbleeds compared to patients with dSSI. Using high resolution MRI (3T), main trunk MCA plaques were detected in 20 patients. In terms of plaque location, superiorly located plaques were more frequently seen in pSSI patients, which the authors speculate could be important in determining the type of SSI.

It must be noted that this study is too small to make any general conclusions about the clinical characteristics of subcortical strokes. Moreover, the high resolution MRI protocol only assessed the main trunk of MCA, so M2 branches and distal MCA vessels are not accounted for. This speaks to the need for more sensitive and accurate radiological methods in the future in studying the cerebrovasculature.