APT Weighted MRI as an Effective Imaging Protocol to Predict Clinical Outcome After Acute Ischemic Stroke

Abstract

To explore the capability of the amide-proton-transfer weighted (APTW) magnetic resonance imaging (MRI) in the evaluation of clinical neurological deficit at the time of hospitalization and assessment of long-term daily functional outcome for patients with acute ischemic stroke (AIS). We recruited 55 AIS patients with brain MRI acquired within 24–48 h of symptom onset and followed up with their 90-day modified Rankin Scale (mRS) score. APT weighted MRI was performed for all the study subjects to measure APTW signal quantitatively in the acute ischemic area (APTWipsi) and the contralateral side (APTWcont). Change of the APT signal between the acute ischemic region and the contralateral side (ΔAPTW) was calculated. Maximum APTW signal (APTWmax) and minimal APTW signal (APTWmin) were also acquired to demonstrate APTW signals heterogeneity (APTWmax−min). In addition, all the patients were divided into 2 groups according to their 90-day mRS score (good prognosis group with mRS score <2 and poor prognosis group with mRS score ≥2). In the meantime, ΔAPTW of these groups was compared. We found that ΔAPTW was in good correlation with National Institutes of Health Stroke Scale (NIHSS) score (R2 = 0.578, p < 0.001) and 90-day mRS score (R2 = 0.55, p < 0.001). There was significant difference of ΔAPTW between patients with good prognosis and patients with poor prognosis. Plus, APTWmax−min was significantly different between two groups. These results suggested that APT weighted MRI could be used as an effective tool to assess the stroke severity and prognosis for patients with AIS, with APTW signal heterogeneity as a possible biomarker.

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

“…The APTW signal within the infarction ROI was significantly lower in the poor prognosis group than in the good prognosis group, which was similar to the findings of Lin et al [29]. .…”

“…The APTW signal within the infarction was significantly inversely correlated with both the NIHSS score on admission and the mRS score at the chronic phase. Lin et al [29] have previously shown that the difference of the APTW signal between the acute ischemic region and the contralateral side is linearly correlated with both the NHISS score and mRS score. Thus, these results indicate that the APTW signal may be a useful tool to assess stroke severity and predict outcome.…”

Amide Proton Transfer Weighted Imaging Shows Differences in Multiple Sclerosis Lesions and White Matter Hyperintensities of Presumed Vascular Origin

“…The recently introduced molecular imaging technique amide proton transfer weighted (APTw) imaging characterized by its high degree of rescan reproducibility, repeatability and reliability (13)(14)(15)(16) has been successfully utilized in imaging of brain tumors and neurodegenerative diseases (14,15,(17)(18)(19). While APTw imaging based on 3D fast spin echo sequences and magnetization transfer asymmetry (MTR asym ) analysis may be confounded by relayed NOE effects, it offers an efficient way of characterizing tissue related changes in APT CEST effects with a 3D coverage of the brain.…”

Noninvasive Detection of Extracellular pH in Human Benign and Malignant Liver Tumors Using CEST MRI

“…Amide proton transfer (APT) has been developed from CEST imaging and has been described by many researchers. APT-CEST-MRI is highly sensitive to pH changes and can clinically evaluate ischemic stroke; hence, APT is associated with a lower pHe because CEST MRI soon after an ischemic events does not alter the mobile protein concentration in the lesion relative to the surrounding tissue (38,39). It is also used to monitor tumor pH (40).…”