Proton magnetic resonance spectroscopy and cognitive impairment in patients with ischemic white matter lesions

The purpose of this study is to investigate the relationship between the cognitive impairment and NAA/Cr and Cho/Cr ratios in the proton magnetic resonance spectroscopy (1HMRS), and to assess the importance of 1HMRS in the early diagnosis of cognitive impairment in patients with ischemic white matter lesions (WMLs). A total of 45 patients (23males and 22 females) with the ischemic WML were divided into mild WML group (n = 15), moderate WML group (n = 15), and severe WML group (n = 15). A total of 15 healthy controls (8 males and 7 females) with no WML on magnetic resonance imaging were included. 1HMRS focusing on the frontal lobe white matter around the anterior horn of the lateral ventricle and Montreal Cognitive Assessment (MoCA) were conducted. Patients with more severe WML had lower MoCA scores. The NAA/Cr ratio in 1HMRS was reduced in all the patients and was strongly correlated with the total MoCA scores (r = 0.845, P < 0.001). The Cho/Cr ratio in 1HMRS was increased in mild and moderate patients, was negatively correlated with the total MoCA scores (r = 0.907, P < 0.001). The Cho/Cr ratio was reduced in the severe patients and was positively correlated with the total MoCA scores(r = 0.937, P < 0.001). In addition, NAA/Cr and Cho/Cr ratios in 1HMRS were changed in patients with the mild WML whose total MoCA scores were similar to the controls. Our results suggest that NAA/Cr and Cho/Cr ratios in 1HMRS are useful indicators for early diagnosis of ischemic WML and cognitive impairment in patients with ischemic WML.