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Updated: Mar 6, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Evolution of Cerebral Ischemia Assessed by Amide Proton Transfer-Weighted MRI
Guodong Song1, Chunmei Li2, Xiaojie Luo2
1Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China; Graduate School of Peking Union Medical College, Beijing, China.
Abstract:
Amide proton transfer-weighted (APTW) magnetic resonance imaging (MRI) has recently become a potentially important tool for evaluating acidosis in ischemic stroke. The purpose of this study was to evaluate the dynamic pH-related changes in the lesions in patients with ischemia. Thirty-nine patients with ischemic stroke (symptom onset to imaging time ranging 2 h-7 days) were examined with a 3.0-T MRI system. Patients were divided into four groups: at the hyperacute stage (onset time ≤ 6 h), at the acute stage (6 h < onset time ≤ 48 h), at the early subacute stage (48 h < onset time ≤ 96 h), and at the late subacute stage (96 h < onset time ≤ 168 h). The APTW signal intensities were quantitatively measured in multiple ischemic regions for each patient. Compared with the contralateral normal white matter, APTW signals were significantly lower in ischemic tissue for all four stages (P < 0.05). The APTW signal intensities (APTWave and APTWmin) increased consistently with onset time (R2 = 0.11, P = 0.040; R2 = 0.13, P = 0.022, respectively). APTWmax-min showed a continued reduction with onset time (R2 = 0.44, P < 0.001). Our results suggest that persistent tissue acidification could occur after ischemia, and as the time from stroke onset increases, the acidotic environment would alleviate. APTW signal intensities could reflect pH-weighted properties in ischemic tissue at different stages and time points.
Insights
Amide proton transfer-weighted (APTW) MRI reveals lower signals in ischemic stroke lesions, indicating acidosis. These APTW signals gradually normalize over time, suggesting a resolving acidic environment post-stroke.
Area of Science:
- Neurology
- Radiology
- Biochemistry
Background:
- Amide proton transfer-weighted (APTW) magnetic resonance imaging (MRI) is emerging as a valuable tool for assessing acidosis in ischemic stroke.
- Understanding the dynamic pH-related changes within ischemic lesions is crucial for stroke management.
Purpose of the Study:
- To evaluate the dynamic pH-related changes in ischemic stroke lesions using APTW MRI.
- To assess how APTW signal intensities correlate with the time elapsed since stroke onset.
Main Methods:
- Thirty-nine ischemic stroke patients were imaged using a 3.0-T MRI system.
- Patients were categorized into four groups based on symptom onset time (hyperacute, acute, early subacute, late subacute).
- Quantitative APTW signal intensities were measured in ischemic regions and compared to contralateral normal white matter.
Main Results:
- APTW signals were significantly lower in ischemic tissue across all four stages compared to normal white matter (P < 0.05).
- APTW signal intensities (APTWave and APTWmin) showed a consistent increase with time since stroke onset (R² = 0.11, P = 0.040; R² = 0.13, P = 0.022).
- APTWmax-min demonstrated a significant reduction with increasing time since onset (R² = 0.44, P < 0.001).
Conclusions:
- Persistent tissue acidification is suggested in ischemic stroke.
- APTW MRI can reflect pH-weighted properties in ischemic tissue, showing an alleviation of the acidic environment over time.
- The findings indicate that APTW signal intensity changes correlate with the temporal evolution of acidosis following ischemic stroke.
