Fig 1.
Study population flowchart.
Table 1.
Percentiles of APTW signal of infarction and CNAWM (n = 29).
Table 2.
Demographic and baseline clinical characteristics and percentiles of APTW signal of cardioembolic (n = 10) and non-cardioembolic (n = 19) infarctions.
Table 3.
Demographic and baseline clinical characteristics and percentiles of APTW signal of the poor prognosis group with mRS score ≥2 (n = 21) and good prognosis group with mRS score <2 (n = 8).
Table 4.
Correlations between percentiles of APTW images and clinico-radiological findings in infarctions (n = 29).
Fig 2.
A 60-year-old male with a hyperacute cardioembolic infarction fifteen hours after the onset.
The pre-stroke mRS score was one. The NIHSS score at the time of admission was 17. The mRS score at 90 days after the onset was one. No signal abnormality is seen on A: T1-weighted image, B: T2-weighted image, and C: FLAIR image. D: DWI shows the hyperintense infarct area in the left frontal lobe. The ROI of the infarct area (red line) and the CNAWM (green line) is indicated. E: The infarct area shows restricted diffusivity (mean ADC = 0.41 × 10−3 mm2/sec). F: MR angiography shows the occlusion of the frontal branch of the left middle cerebral artery (arrow). G: The infarct area was hypointense on the APTW image (APT10 = –3.52%, APT25 = –2.90%, APT50 = –2.13%, APT75 = –0.22%, APT90 = 1.50%) (arrowheads). On the visual grading scale, this case was graded as clear by both raters. H: Z-spectra show a lower CEST effect in the entire offset range (–6 to +6 ppm) in the infarct area compared to the CNAWM. G: MTRasym spectra show decreased MTRasym (3.5ppm) or APTW signal (%) in the infarct area compared to the CNAWM. mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; FLAIR, fluid attenuated inversion recovery; DWI, diffusion-weighted imaging; ROI, region-of-interest; ADC, apparent diffusion coefficient; APTW, amide proton transfer-weighted; CEST, chemical exchange saturation transfer; CNAWM, contralateral normal-appearing white matter; Ssat(ppm) and S0, the signal intensities obtained with and without selective radiofrequency saturation pulse irradiation, respectively; APT10, APT25, APT50, APT75, and APT90 correspond to the 10th, 25th, 50th, 75th, and 90th percentiles of the APTW signal value within the ROI, respectively.
Fig 3.
A 27-year-old female with an acute cardioembolic infarction fifteen hours after the onset.
The pre-stroke mRS score was zero. The NIHSS score at the time of admission was 15. The mRS score at 90 days after the onset was four. The infarct area in the left cerebral hemisphere is hypointense on A: T1-weighted image; and hyperintense on B: T2-weighted image, C: FLAIR, and D: DWI. The ROI of the infarct area (red line) and the CNAWM (green line) is indicated. E: The infarct area shows restricted diffusivity (mean ADC = 0.36 × 10−3 mm2/sec). F: MR angiography shows the occlusion of the left middle cerebral artery (arrow). G: The infarct area was hypointense on the APTW image (APT10 = –2.29%, APT25 = –1.93%, APT50 = –1.51%, APT75 = –1.10%, APT90 = –0.69%) (arrowheads). This case was graded as clear by both raters according to the visual grading scale. H: Z-spectra show a lower CEST effect in entire offset range (–6 to +6 ppm) in the infarct area compared to the CNAWM. G: MTRasym spectra show decreased MTRasym(3.5ppm) or APTW signal (%) in the infarct area compared to the CNAWM. mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; FLAIR, fluid attenuated inversion recovery; DWI, diffusion-weighted imaging; ROI, region-of-interest; ADC, apparent diffusion coefficient; APTW, amide proton transfer-weighted; CEST, chemical exchange saturation transfer; CNAWM, contralateral normal-appearing white matter; Ssat(ppm) and S0, the signal intensities obtained with and without selective radiofrequency saturation pulse irradiation, respectively; APT10, APT25, APT50, APT75, and APT90, correspond to the 10th, 25th, 50th, 75th, and 90th percentiles of APTW signal value, respectively.
Fig 4.
A 59-year-old male with a subacute atherosclerotic infarction nine days after the onset.
The pre-stroke mRS score was zero. The NIHSS score at the time of admission was 10. The mRS score at 90 days after the onset was four. The infarct area in the right cerebellar hemisphere is hypointense on A: T1-weighted image; and hyperintense on B: T2-weighted image, C: FLAIR, and D: DWI. The ROI of the infarct area (red line) and the CNAWM (green line) are indicated. E: The infarct area shows restricted diffusivity (mean ADC = 0.51 × 10−3 mm2/sec). F: MR angiography shows the terminus stenosis of the right internal carotid artery (arrow). G: The infarct area was relatively hypointense on the APTW image (APT10 = –0.68%, APT25 = –0.41%, APT50 = –0.07%, APT75 = 0.30%, APT90 = 0.64%) (arrowheads). This case was graded as moderate by both raters on the visual grading scale. H: Z-spectra show a lower CEST effect in the entire offset range (–6 to +6 ppm) in the infarct area compared to the CNAWM. G: MTRasym spectra show decreased MTRasym(3.5ppm) or APTW signal (%) in the infarct area compared to the CNAWM. mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; FLAIR, fluid attenuated inversion recovery; DWI, diffusion-weighted imaging; ROI, region-of-interest; ADC, apparent diffusion coefficient; APTW, amide proton transfer-weighted; CEST, chemical exchange saturation transfer; CNAWM, contralateral normal-appearing white matter; Ssat (ppm) and S0, the signal intensities obtained with and without selective radiofrequency saturation pulse irradiation, respectively; APT10, APT25, APT50, APT75, and APT90, correspond to the 10th, 25th, 50th, 75th, and 90th percentiles of APTW signal value, respectively.