MRI T1信号强度比与复发性急性及慢性胰腺炎纤维化的相关性

PURPOSE: T1 signal intensity ratio (SIR) on MRI has not been rigorously evaluated as a noninvasive method to detect pancreatic fibrosis in patients undergoing surgery for recurrent acute (RAP) and chronic pancreatitis (CP). The aim of our study was to evaluate the association between histologic fibrosis score (FS) and T1 SIR and contrast enhancement of the pancreas on MRI among patients with RAP and CP undergoing total pancreatectomy with islet autotransplantation (TPIAT).

METHODS: Patients who underwent MRI < 6 months before TPIAT between 2011 and 2023 were classified into 3 groups: definite CP (n = 23) and indeterminate CP (n = 11) by M-ANNHEIM criteria; and RAP defined as ≥ 2 episodes of imaging-documented acute pancreatitis (n = 22). The perilobular and intralobular fibrosis of each surgical biopsy was scored from 0 to 6. The FS was the sum of perilobular and intralobular fibrosis (0-12). We measured the T1 signal intensity of the pancreas and reference organs using pre-contrast T1-weighted fat-saturated (T1WFS) sequences to obtain the T1 SIR. We also measured the T1 signal intensity of the pancreas in the pre-contrast, arterial, venous, and delayed phases.

RESULTS: A total of 56 patients were included. The median FS was 6.25 (range 0-12). Pancreas-to-spleen T1 SIR (p = 0.004) and pancreas-to-paraspinal T1 SIR (p = 0.03) were significantly associated with pancreatic fibrosis after adjusting for age, BMI, exocrine insufficiency, fat fraction, diabetes mellitus, and clinical diagnosis. Analysis of the enhancement curves showed that the venous phase of T1 signal intensity can differentiate between indeterminate CP, RAP and definite CP (p < 0.004 for all).

CONCLUSION: Both the T1 SIR of the pancreas-to-spleen and pancreas-to-paraspinal muscle show an independent association with fibrosis. T1 SIR demonstrates a significant association with histologically quantified pancreatic fibrosis and may serve as a promising noninvasive imaging biomarker pending further validation.