Correlations of amide proton transfer-weighted MRI of cerebral infarction with clinico-radiological findings

OBJECTIVE: To clarify the relationship between amide proton transfer-weighted (APTW) signal, which reflects intracellular pH, and clinico-radiological findings in patients with hyperacute to subacute cerebral infarction. MATERIALS AND METHODS: Twenty-nine patients (median age, 70 years [IQR, 54 to 74]; 15 men) were retrospectively examined. The 10th, 25th, 50th, 75th, and 90th percentiles of APTW signal (APT(10), APT(25), APT(50), APT(75) and APT(90), respectively) were measured within the infarction region-of-interest (ROI), and compared between poor prognosis and good prognosis groups (modified Rankin Scale [mRS] score ≥2 and mRS score <2, respectively). Correlations between APTW signal and time after onset, lesion size, National Institutes of Health Stroke Scale (NIHSS) score, mRS score, and mean apparent diffusion coefficient (ADC) were evaluated. RESULTS: The poor prognosis group had lower APT(50), APT(75), and APT(90) than the good prognosis group (–0.66 [–1.19 to –0.27] vs. –0.09 [–0.62 to –0.21]; –0.27 [–0.63 to –0.01] vs. 0.31 [–0.15 to 1.06]; 0.06 [–0.21 to 0.34] vs. 0.93 [0.36 to 1.50] %; p <0.05, respectively). APT(50) was positively correlated with time after onset (r = 0.37, p = 0.0471) and negatively with lesion size (r = –0.39, p = 0.0388). APT(75) and APT(90) were negatively correlated with NIHSS (r = –0.41 and –0.43; p <0.05, respectively). APT(50), APT(75) and APT(90) were negatively correlated with mRS (r = –0.37, –0.52 and –0.57; p <0.05, respectively). APT(10) and APT(25) were positively correlated with mean ADC (r = 0.37 and 0.38; p <0.05, respectively). CONCLUSION: We demonstrated correlations between APTW signals of infarctions and clinico-radiological findings in patients with hyperacute to subacute infarctions. The poor prognosis group had a lower APTW signal than the good prognosis group. APTW signal was reduced in large infarctions, infarctions with low ADC, and in patients with high NIHSS and mRS scores.