The pancreas in β-thalassemia major: MR imaging features and correlation with iron stores and glucose disturbunces

Abstract

The study aims at describing the MR features of pancreas in beta-thalassemia major, investigating the relations between MR findings and glucose disturbances and between hepatic and pancreatic siderosis. Signal intensity ratios of the pancreas and liver to right paraspinous muscle (P/M, L/M) were retrospectively assessed on abdominal MR imaging studies of 31 transfusion-dependent patients with beta-thalassemia major undergoing quantification of hepatic siderosis and 10 healthy controls, using T1- (120/4/90), intermediate in and out of phase - (120/2.7, 4/20), and T2*-(120/15/20) weighted GRE sequences. Using the signal drop of the liver and pancreas on opposed phase images, we recorded serum ferritin and results of oral glucose tolerance test (OGTT). Decreased L/M and P/M on at least the T2* sequence were noticed in 31/31 and 30/31 patients, respectively, but no correlation between P/M and L/M was found. Patients with pathologic OGTT displayed a higher degree of hepatic siderosis (p < 0.04) and signal drop of pancreas on opposed phase imaging (p < 0.025), implying fatty replacement of pancreas. P/M was neither correlated with glucose disturbances nor serum ferritin. Iron deposition in the pancreas cannot be predicted by the degree of hepatic siderosis in beta-thalassemia major. Fatty replacement of the pancreas is common and may be associated with glucose disturbances.

A T2* magnetic resonance imaging study of pancreatic iron overload in thalassemia major

“…It is known that pancreatic hemosiderosis results in abnormal MRI signal intensity, and there is iron overload in the pancreas in up to 75-100% of thalassemia major cases. [7][8][9] The signal intensity ratio results showed correlation with ferritin levels 9 and also related to iron load in other organs. 7 They also correlated with exocrine pancreatic secretion function 9 and endocrine function as assessed by oral glucose tolerance test (OGTT).…”

“…Our study showed that pancreatic atrophy (volume) was a better predictor of diabetic status than pancreatic hemosiderosis (T2*). In other studies, MRI documented pancreatic fatty replacement has also been shown to predict diabetes 8 Pancreatic damage represents an irreversible, cumulative destruction of ␤ cells 15 and pancreatic atrophy is a common finding in all diabetes patients irrespective of etiology. 16 Unlike the heart or liver, the pancreas may not regenerate or remodel even with reduction in hemosiderosis.…”

“…13 We also confirmed that pancreatic hemosiderosis did not correlate with liver hemosiderosis. 8 However, there was strong correlation between hemosiderosis of the pancreas and heart. This may be due to the same L-type calcium iron channels in the two organs.…”

“…7 They also correlated with exocrine pancreatic secretion function 9 and endocrine function as assessed by oral glucose tolerance test (OGTT). 8 Pancreatic abnormalities in thalassemia major patients can also be defined by other imaging modalities such as ultrasound echogenicity. 10 However, MRI has become an integral part of iron assessment in thalassemia, so new pancreatic MRI studies using other signal algorithms are urgently needed.…”

Impact of magnetic resonance imaging on cardiac mortality in thalassemia major

“…Recently, with the use of magnetic resonance imaging (MRI) not only can the total body iron be evaluated, but organ-specific iron assessments, particularly the heart, can be acquired (3)(4)(5)(6)(7). This allows the tailoring of chelation therapy.…”