Xiaojie Luo MD, Presenter: Nothing to Disclose

Jinyuan Zhou PhD, Abstract Co-Author: Nothing to Disclose

min chen, Abstract Co-Author: Nothing to Disclose

APT imaging is a new MRI methodology that can non-invasively detect tissue pH. Here, we evaluated ischemic penumbra due to tissue acidosis and prognosis in patients with acute stroke using APT imaging.

Ten patients (M = 5, average years = 70.1 ± 10.7) with the onset of acute stroke symptoms (uncertain onset <24h, n = 2; 24h~36h, n = 8) from the anterior or posterior circulation were included in this study. They were underwent MRI 4 times, which would be first MR scanning after hospitalization, and then one day, one week and one month after treatments. Amide Proton Transfer (APT) images (saturation time 0.8 s, saturation power 2 µT) and Diffusion Weighted Images (DWI) were included in the scanning protocols under 3.0 Tesla MR scanner. APT images were calculated using magnetization transfer ratio asymmetry at 3.5ppm with respect to water. APT intensity values in normal-appearing white matter (NAWM) were compared with those of ischemic regions. Comparison of ischemic regions between DWI and APT images was reported. NIHSS (National Institute of Health stroke scale) score of each patient was assessed before and after courses of treatments.

On average, ischemic regions (APT value, -0.40% ± 0.14%) in patients showed significantly reduced (p < 0.0001) APT effects compared with NAWM (APT value, 0.23% ± 0.12%). Ischemic regions were about 10%~50% larger in APT images than in DWI (final infarct region), or just alike in size between two modalities in first MR scanning after hospitalization. In some cases, regions with reduced APT were not only observed at the ischemic spots, but also extended to some adjacent brain areas which might indicate potential infarction. After treatment, the findings varied between patients; generally, a trend for a reduced APT signal in the final infarct region and a restored APT signal in at-risk tissue was observed. NIHSS scores showed improved as patients’ ischemic regions in APT images became smaller. However, patients with similar size in two modalities did not show better prognosis.

APT images could be more accurate in defining the ischemic penumbra, thus help to determine therapy and improve prognosis.

Patients with acute stroke after onset of 36 hours might still have neurons that can be resuscitated, and APT images would help to detect the tissues.

Luo, X, Zhou, J, chen, m, Whether there Exist Neurons That Could Be Resuscitated in Patients with Acute Stroke after Onset of 36 Hours: Evaluation with Amide Proton Transfer (APT) MRI.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015416.html