Non‐invasive imaging of functional pancreatic islet beta‐cell mass in people with type 1 diabetes mellitus

Abstract

AbstractAimsTo investigate whether manganese‐enhanced magnetic resonance imaging can assess functional pancreatic beta‐cell mass in people with type 1 diabetes mellitus.MethodsIn a prospective case–control study, 20 people with type 1 diabetes mellitus (10 with low (≥50 pmol/L) and 10 with very low (<50 pmol/L) C‐peptide concentrations) and 15 healthy volunteers underwent manganese‐enhanced magnetic resonance imaging of the pancreas following an oral glucose load. Scan‐rescan reproducibility was performed in 10 participants.ResultsMean pancreatic manganese uptake was 31 ± 6 mL/100 g of tissue/min in healthy volunteers (median 32 [interquartile range 23–36] years, 6 women), falling to 23 ± 4 and 13 ± 5 mL/100 g of tissue/min (p ≤ 0.002 for both) in people with type1 diabetes mellitus (52 [44–61] years, 6 women) and low or very low plasma C‐peptide concentrations respectively. Pancreatic manganese uptake correlated strongly with plasma C‐peptide concentrations in people with type1 diabetes mellitus (r = 0.73, p < 0.001) but not in healthy volunteers (r = −0.054, p = 0.880). There were no statistically significant correlations between manganese uptake and age, body‐mass index, or glycated haemoglobin. There was strong intra‐observer (mean difference: 0.31 (limits of agreement −1.42 to 2.05) mL/100 g of tissue/min; intra‐class correlation, ICC = 0.99), inter‐observer (−1.23 (−5.74 to 3.27) mL/100 g of tissue/min; ICC = 0.85) and scan‐rescan (−0.72 (−2.9 to 1.6) mL/100 g of tissue/min; ICC = 0.96) agreement for pancreatic manganese uptake.ConclusionsManganese‐enhanced magnetic resonance imaging provides a potential reproducible non‐invasive measure of functional beta‐cell mass in people with type 1 diabetes mellitus. This holds major promise for investigating type 1 diabetes, monitoring disease progression and assessing novel immunomodulatory interventions.