35-OR: Multicenter MRI Assessment of the Pancreas in Type 1 Diabetes (MAP-T1D) Predicts Progression of Type 1 Diabetes

Pancreas size, as measured by MRI, is smaller at the onset of T1D and in individuals at risk for T1D. To determine whether pancreas MRI predicts T1D progression, we measured pancreas size and shape longitudinally in Type 1 Diabetes TrialNet Pathway to Prevention study participants. To increase enrollment and expand this study across multiple TrialNet sites, we established the Multicenter Assessment of the Pancreas in T1D (MAP-T1D) group to develop harmonized MRI acquisition and image processing protocols and ensure the consistency of imaging results across sites. Using this standardized protocol (PMID: 34428220) , we performed longitudinal pancreas MRI in 41 multiple autoantibody-positive individuals (mean age y.o., range 8 - 45 y.o., 49% female) at three TrialNet Clinical Centers. Average time between study entry and diabetes diagnosis for individuals who progressed to Stage 3 was 54 months while non-progressors were followed for a median time of 63 months. Five study participants who developed Stage 3 T1D during follow up had a smaller pancreas (29.5 ± 9.0 ml vs. 54.8 ± 22.5 ml, p = 0.02) and smaller pancreas volume normalized by body weight (0.61 ± 0.18 ml/kg vs. 0.85 ± 0.23 ml, p = 0.03) at study entry compared with those who did not progress to Stage 3. We found that pancreas volume was stable over time, with no significant increase or decrease up to four years after the initial MRI (total of 123 MRIs) . There was no significant change in pancreas size in the five individuals who progressed to Stage 3 T1D. The shape of the pancreas at study onset was also different in the five individuals who progressed to Stage 3 T1D compared with non-progressors, with larger surface area to volume ratio (p = 0.02) , and shorter principal axes (p = 0.05, shortest axis; p = 0.02, second shortest axis) . These data suggest that small pancreas size and altered shape predicts progression from Stage 2 to Stage 3 T1D.