Amide Proton Transfer-Weighted Magnetic Resonance Imaging for Application in Renal Fibrosis: A Radiological-Pathological-Based Analysis

Abstract

Plain Language SummaryAmide proton transfer (APT) MRI, a novel molecular MRI technique, could indirectly measure the peptide or protein concentration within tissues based on frequent exchange between amide proton and the surrounding water protons. This new technology has been used in tumor diagnosis. Given pathological conditions linked to tissue fibrogenesis are similar to carcinogenesis, we proposed the hypothesis that APT MRI can be applied to assess collagen deposition in RF. To test this, we constructed animal models for RF and enrolled CKD patients, respectively. The results suggested APT values were more sensitive to the early stage of fibrosis than ADC values, and the cortical APT was highly positively correlated with the degree of fibrosis. We further identified that the combination of two MRI protocols, cortical apparent diffusion coefficient and cortical APT, was an excellent indicator for the diagnosis of fibrosis, with much higher accuracy than a single method. To the best of our knowledge, this is the first study to explore the value of APT imaging for assessing renal interstitial fibrosis. Our findings identify APT as a novel and precise imaging diagnostic tool for future noninvasive assessment of RF. It complements with the existing imaging biomarkers and adds value to conventional MRI.