Assessment of Pancreas Volume and Shape Dynamics Longitudinally after T1D Diagnosis

The pancreas is smaller in individuals with T1D, but the correlation between pancreas volume and disease progression is not well established. Longitudinal pancreas volume measurements indicate that pancreas volume declines over the first year after diagnosis with T1D. To further assess pancreas volume and shape, we performed MRI imaging in 55 participants imaged at the onset of T1D and at multiple timepoints up to 5 years after diagnosis. In this cohort, 106 MRIs were performed in the first year after diagnosis, 52 MRIs in the second year, 26 in the third year, 4 MRIs in the fourth year, and 4 MRIs in the fifth year. In a primarily adolescent population, controls without T1D had increasing pancreas volume measured over a year of follow up (p = 0.01), but individuals with T1D followed up to 5 years after diagnosis showed no increase (p = 0.598). When normalizing pancreas volume by body weight (referred to as pancreas volume index) to control for adolescent weight gain, pancreas volume index declined in the 5 years after T1D diagnosis (p < 0.0005), compared with a stable pancreas volume index over time in controls (p < 0.05, difference in slopes over time). A separate cohort of individuals with longstanding T1D (n = 22, mean duration = 23 years, range 13 - 57 years) were imaged a single time. Pancreas volume index in individuals with T1D duration greater than 10 years was significantly smaller than in individuals with duration shorter than 10 years (p < 0.001). In addition to alterations in pancreas volume, we found changes in pancreas shape in T1D. The surface area to volume ratio of the pancreas is higher in T1D than in controls, indicating a thinner pancreas in T1D (p < 0.001). Furthermore, the surface area to volume ratio was stable over time in T1D, but decreased over follow up in controls (p < 0.05). These data indicate altered longitudinal pancreas dynamics in the 5 years after T1D onset compared with controls, indicating impaired pancreas growth in adolescents with T1D. Disclosure J. Virostko: None. J.M. Williams: None. M.A. Hilmes: None. J.J. Wright: None. L. Du: None. H. Kang: None. W.E. Russell: None. D.J. Moore: None. A.C. Powers: None. Funding JDRF (3-SRA-2019-759-M-B, 3-SRA-2015-102-M-B)