Application of high-resolution magnetic resonance imaging (MRI) in the evaluation of acupuncture effects in traditional Chinese medicine

Abstract

In the evaluation of acupuncture effects in traditional Chinese medicine (TCM), the unclear interpretation of microscopic mechanisms and the difficulty in verifying acupoint specificity due to insufficient resolution of MRI (Magnetic Resonance Imaging) are the main reasons for the difficulty. This paper adopts 7T ultra-high field MRI combined with dynamic ASL (arterial spin labeling) technology, taking advantage of its high spatial resolution and quantitative blood perfusion imaging, to achieve dynamic visualization of microcirculation at acupuncture points in patients with ulcerative colitis. Ulcerative colitis is an ideal site to verify the feasibility of this method because its lesion site is clear and easy to correspond with the body surface acupoint. This paper establishes a high-resolution imaging protocol based on 7T magnetic resonance imaging, adopts 0.5mm spatial resolution, and optimizes scanning parameters to adapt to the microstructural imaging requirements of the acupoint area. This paper introduces pCASL (pseudo-continuous arterial spin labeling) technology, sets the labeling duration and perfusion delay time, captures the changes in perfusion volume before and after acupuncture over time, and obtains a dynamic perfusion sequence. This paper adopts umbilical moxibustion therapy, selects specific meridian acupoints, sets a standard acupuncture stimulation scheme (needle insertion depth, frequency, and needle retention time), and simultaneously performs MRI scanning to achieve real-time acupuncture imaging acquisition. The acquired multi-time point images can be rigidly registered and mapped with standard templates, the blood flow intensity change curve of the acupuncture-related area can be extracted, and the time-perfusion function can be constructed to analyze the local response pattern. The experimental results show that the ΔCBF (Delta Cerebral Blood Flow) of 7T-ASL at Shenque, Tianshu and Zhongwan are 0.15, 0.12 and 0.18 respectively, and it has high sensitivity in capturing tiny blood flow changes under sub-millimeter resolution. The SNR (Signal-to-Noise Ratio) at Shenque, Tianshu and Zhongwan are 22, 25 and 24 respectively, and the CNR (Contrast-to-Noise Ratio) is 6.2, 6.5 and 6.7 respectively, which has significant advantages in the spatial identification of sensitive areas of neural regulation and the identification of perfusion response. The average rising rate, peak time and recovery time in all acupoints were 2.44%/s, 7.2s and 11.5s respectively, and the acupuncture effect took effect faster in local areas.