Depiction of Acute Stroke Using 3-Tesla Clinical Amide Proton Transfer Imaging: Saturation Time Optimization Using an in vivo Rat Stroke Model, and a Preliminary Study in Human.
10.13104/imri.2017.21.2.65
- Author:
Ji Eun PARK
1
;
Ho Sung KIM
;
Seung Chai JUNG
;
Jochen KEUPP
;
Ha Kyu JEONG
;
Sang Joon KIM
Author Information
1. Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. dynamics79@gmail.com
- Publication Type:Original Article
- Keywords:
Amide proton transfer;
Stroke;
pH-difference;
Saturation time
- MeSH:
Animals;
Brain;
Head;
Humans*;
Infarction, Middle Cerebral Artery;
Magnetic Resonance Imaging;
Male;
Models, Animal;
Protons*;
Rats*;
Rats, Wistar;
Stroke*;
Water
- From:Investigative Magnetic Resonance Imaging
2017;21(2):65-70
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: To optimize the saturation time and maximizing the pH-weighted difference between the normal and ischemic brain regions, on 3-tesla amide proton transfer (APT) imaging using an in vivo rat model. MATERIALS AND METHODS: Three male Wistar rats underwent middle cerebral artery occlusion, and were examined in a 3-tesla magnetic resonance imaging (MRI) scanner. APT imaging acquisition was performed with 3-dimensional turbo spin-echo imaging, using a 32-channel head coil and 2-channel parallel radiofrequency transmission. An off-resonance radiofrequency pulse was applied with a Sinc-Gauss pulse at a B(1,rms) amplitude of 1.2 µT using a 2-channel parallel transmission. Saturation times of 3, 4, or 5 s were tested. The APT effect was quantified using the magnetization-transfer-ratio asymmetry at 3.5 ppm with respect to the water resonance (APT-weighted signal), and compared with the normal and ischemic regions. The result was then applied to an acute stroke patient to evaluate feasibility. RESULTS: Visual detection of ischemic regions was achieved with the 3-, 4-, and 5-s protocols. Among the different saturation times at 1.2 µT power, 4 s showed the maximum difference between the ischemic and normal regions (-0.95%, P = 0.029). The APTw signal difference for 3 and 5 s was -0.9% and -0.7%, respectively. The 4-s saturation time protocol also successfully depicted the pH-weighted differences in an acute stroke patient. CONCLUSION: For 3-tesla turbo spin-echo APT imaging, the maximal pH-weighted difference achieved when using the 1.2 µT power, was with the 4 s saturation time. This protocol will be helpful to depict pH-weighted difference in stroke patients in clinical settings.
