Development of a standardized MRI protocol for pancreas assessment in humans.

John Virostko,Thomas W H Kay,Richard C Craddock,Alvin C Powers,Hakmook Kang,Michaela Waibel,Siri Atma W Greeley,Taylor M Triolo,Liping Du,Melissa A Hilmes,Mara Kinney,Daniel J Moore,Milica Medved,Jonathan M Williams,Jordan J Wright,Andrea K Steck,Jeffrey H Maki,Helen E Thomas,Mingwu Jin

doi:10.1371/journal.pone.0256029

Abstract

Magnetic resonance imaging (MRI) has detected changes in pancreas volume and other characteristics in type 1 and type 2 diabetes. However, differences in MRI technology and approaches across locations currently limit the incorporation of pancreas imaging into multisite trials. The purpose of this study was to develop a standardized MRI protocol for pancreas imaging and to define the reproducibility of these measurements. Calibrated phantoms with known MRI properties were imaged at five sites with differing MRI hardware and software to develop a harmonized MRI imaging protocol. Subsequently, five healthy volunteers underwent MRI at four sites using the harmonized protocol to assess pancreas size, shape, apparent diffusion coefficient (ADC), longitudinal relaxation time (T1), magnetization transfer ratio (MTR), and pancreas and hepatic fat fraction. Following harmonization, pancreas size, surface area to volume ratio, diffusion, and longitudinal relaxation time were reproducible, with coefficients of variation less than 10%. In contrast, non-standardized image processing led to greater variation in MRI measurements. By using a standardized MRI image acquisition and processing protocol, quantitative MRI of the pancreas performed at multiple locations can be incorporated into clinical trials comparing pancreas imaging measures and metabolic state in individuals with type 1 or type 2 diabetes.

Highlights

Magnetic resonance imaging (MRI) plays an important role in the diagnosis and monitoring of a number of pancreatic disorders including chronic [1] and acute [2] pancreatitis, nonalcoholic fatty pancreas disease [3], and pancreatic cancer [4]
The apparent diffusion coefficient (ADC), magnetization transfer ratio (MTR), and fat fraction measurements were compared across sites, resulting in coefficients of variation of 4.3%, 8.9%, and 0.4%, respectively, across the five sites
This study is the first effort to generate a standardized pancreas MRI protocol for techniques that are being used for studying diabetes

Summary

Introduction

MRI plays an important role in the diagnosis and monitoring of a number of pancreatic disorders including chronic [1] and acute [2] pancreatitis, nonalcoholic fatty pancreas disease [3], and pancreatic cancer [4]. Longitudinal imaging in individuals with diabetes demonstrates dynamic changes in pancreas size, including declines over the natural history of type 1 diabetes [5] and increases in individuals with type 2 diabetes who respond to treatment [11] These results suggest that MRI may have important applications in diabetes research and clinical management of the disease. Radiomics offers a complementary approach, in which numerical features, some of which are directly related to physical or physiological properties of the imaged tissue, are extracted from the MRI data and evaluated mathematically The advantage of this quantitative approach is that it can be sensitive to nuanced differences in images that are hard or impossible to detect visually. Measures of pancreas fat may be associated with diabetes [19] and may correlate with therapeutic response [20]

Objectives

Methods

Results

Conclusion