Clinical risk factors and ultrahigh field magnetic resonance imaging features of cerebral microinfarcts

Objective To analyze the risk factors of cortical micro-infarcts (CMIs) in patients with acute ischemic stroke and to evaluate the diagnostic value of 3.0 Tesla (T) magnetic resonance imaging (MRI) using double inversion recovery (DIR) sequence and 3-dimensional fluid attenuated inversion recovery (3D-FLAIR) sequence in CMIs in vivo. Methods One hundred and ten consecutive patients with acute ischemic stroke within 7 d of onset were chosen from August 2014 to July 2015; these patients were classified into CMIs group and non-CMIs group by results of 3.0 conventional T MRI, DIR-MRI and 3D-FLAIR-MRI. Baseline characteristics and risk factors were analyzed to investigate the independent risk factors of CMIs. The presence of CMIs was evaluated based on conventional T MRI, DIR-MRI and 3D-FLAIR-MRI. Results Of the 110 enrolled patients with acute ischemic stroke, CMIs were presented in 23.6% patients(26/110). The age of patients from the CMIs group was significantly older as compared with that of patients from the non-CMIs group (67.65±10.37 vs. 58.52±11.24 years old, P=0.009). Patients from the CMIs group had significantly higher percentages of age>65 years, age of 76-80 years, hypertension, history of cerebral ischemia and intracranial atherosclerosis than patients from non-CMIs group (P 65 years (OR=1.982; 95%CI: 1.362-2.889, P=0.010) and hypertension (OR=1.326; 95%CI: 1.022-1.682, P=0.026) were the independent risk factors of CMIs. The prevalence of CMIs detected by conventional sequence (10.9%) was significantly lower than that detected by DIR sequence (23.6%) or 3D-FLAIR sequence (20.9%, P=0.013 and P=0.043). Conclusions Age>65 years and hypertension are independent risk factors of CMIs. DIR and 3D-FLAIR sequences at 3.0 T MRI substantially improve the sensitivity of detection of CMIs as compared with conventional MRI sequence. Key words: Cortical micro-infarct; Double inversion recovery; 3-dimensional fluid attenuated inversion recovery; Ischemic stroke