Multi-frequency magnetic resonance elastography of the pancreas: measurement reproducibility and variance among healthy volunteers

Abstract

Background Patients with chronic pancreatitis often have irreversible pancreatic insufficiency before a clinical diagnosis. Pancreatic cancer is a fatal malignant tumor in the advanced stages. Patients having high risk of pancreatic diseases must be screened early to obtain better outcomes using new imaging modalities. Therefore, this study aimed to investigate the reproducibility of tomoelastography measurements for assessing pancreatic stiffness and fluidity and the variance among healthy volunteers. Methods Forty-seven healthy volunteers were prospectively enrolled and underwent two tomoelastography examinations at a mean interval of 7 days. Two radiologists blindly and independently measured the pancreatic stiffness and fluidity at the first examination to determine the reproducibility between readers. One radiologist measured the adjacent pancreatic slice at the first examination to determine the reproducibility among slices and measured the pancreas at the second examination to determine short-term repeatability. The stiffness and fluidity of the pancreatic head, body, and tail were compared to determine anatomical differences. The pancreatic stiffness and fluidity were compared based on sex, age, and body mass index (BMI). Results Bland–Altman analyses (all P > 0.05) and intraclass correlation coefficients (all >0.9) indicated near perfect reproducibility among readers, slices, and examinations at short intervals. Neither stiffness (P = 0.477) nor fluidity (P = 0.368) differed among the pancreatic anatomical regions. The mean pancreatic stiffness was 1.45 ± 0.09 m/s; the mean pancreatic fluidity was 0.83 ± 0.06 rad. Stiffness and fluidity did not differ by sex, age, or BMI. Conclusion Tomoelastography is a promising and reproducible tool for assessing pancreatic stiffness and fluidity in healthy volunteers.

Single Breath‐Hold MR Elastography for Fast Biomechanical Probing of Pancreatic Stiffness

“…These improved results support the hypothesis of superior repeatability that would result from the stable positioning of the pancreas within a single breath‐hold compared to deviations in positioning between multiple breath‐holds for the other acquisitions. Nonetheless, in a more recent study by Shi et al, the 95% LoA reported were [−0.072, 0.088] m/second at an approximately 7‐day interval using a multi‐frequency approach 40 …”

“…The results obtained for both the within-subject CoV and LoA showed improved results compared to previously published work. 10,14,39,40 Shi et al reported a lower withinsubject CoV of 13.4% at 40 Hz compared to 60 Hz. 10 An et al reported 95% LoA of [À0.51, 0.60] kPa between two scans obtained a day apart.…”

“…Nonetheless, in a more recent study by Shi et al, the 95% LoA reported were [À0.072, 0.088] m/second at an approximately 7-day interval using a multi-frequency approach. 40…”

Quantitative Magnetic Resonance Imaging for the Pancreas

“…2). 13,16,130 Olesen et al 16 reported that MRE possessed superior properties for the identification of patients with early chronic pancreatitis compared with T1 relaxation time, PDFF, and IVIM parameters.…”

“…131,132 Chronic pancreatitis is characterized by perilobular fibrosis; however, it exhibits a significantly lower mean collagen composition versus PDAC. 131 Several studies have reported that stiffness is significantly higher in PDACs versus the health pancreas or chronic pancreatitis, 124,128,130,[133][134][135][136] reflecting the characteristic histological features of PDAC and chronic pancreatitis. 131,132 The utility of MRE for differentiating PDAC from autoimmune pancreatitis has also been reported by 2 studies.…”