Multicenter validation of the magnetic resonance T2* technique for quantification of pancreatic iron.

OBJECTIVES: To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2* technique for pancreatic iron overload assessment. METHODS: Multiecho T2* sequences were installed on ten 1.5-T MRI scanners of the three main vendors. Five healthy subjects (n = 50) were scanned at each site. Five patients with thalassemia (n = 45) were scanned locally at each site and were rescanned at the reference site within 1 month. T2* images were analyzed using a previously validated software and the global pancreatic T2* value was calculated as the mean of T2* values over the head, body, and tail. RESULTS: T2* values of healthy subjects were above 26 ms and showed inter-site homogeneity. The T2* values measured in the MRI sites were comparable to the correspondent values observed in the reference site (12.02 ± 10.20 ms vs 11.98 ± 10.47 ms; p = 0.808), and the correlation coefficient was 0.978 (p < 0.0001). Coefficients of variation (CoVs) ranged from 4.22 to 9.77%, and the CoV for all the T2* values independently from the sites was 8.55%. The intraclass correlation coefficient (ICC) for each MRI site was always excellent and the global ICC was 0.995, independently from the sites. The mean absolute difference in patients with pancreatic iron (n = 39) was -0.15 ± 1.38 ms. CONCLUSION: The gradient-echo T2* MRI technique is an accurate and reproducible means for the quantification of pancreatic iron and may be transferred among MRI scanners by different vendors in several centers. KEY POINTS: • The gradient-echo T2* MRI technique is an accurate and reproducible means for the quantification of pancreatic iron. • The gradient-echo T2* MRI technique for the quantification of pancreatic iron may be transferred among MRI scanners by different vendors in several centers. • Pancreatic iron might serve as an early predictor of cardiac siderosis and is the strongest overall predictor of glucose dysregulation.

Magnetic Resonance Evaluation of Tissue Iron Deposition and Cardiac Function in Adult Regularly Transfused Thalassemia Intermedia Compared with Thalassemia Major Patients.

Objectives: This multicenter, retrospective, population-based, matched-cohort study compared clinical characteristics and magnetic resonance imaging (MRI) findings, including hepatic, pancreatic, and cardiac iron levels and cardiac function, between 135 adult regularly transfused thalassemia intermedia (TI) patients (44.73 ± 12.16 years, 77 females) and 135 age- and sex-matched thalassemia major (TM) patients (43.35 ± 9.83 years, 77 females), enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. Methods: The MRI protocol included the quantification of hepatic, pancreatic, and cardiac iron levels (R2* technique), the assessment of biventricular function parameters (cine images), and the detection of replacement myocardial fibrosis (late gadolinium enhancement technique). Results: Age, sex, frequency of splenectomy and chelation, and serum ferritin levels were not significantly different (p > 0.05) between the two groups, but TI patients started regular transfusions significantly later (p < 0.0001) and showed significantly lower pre-transfusion hemoglobin levels (p = 0.005). No difference was found in hepatic iron levels (p = 0.853). TI patients exhibited significantly lower pancreatic R2* values (p < 0.0001), also correcting for the duration of regular transfusions, and significantly lower cardiac R2* values (p < 0.0001). In the receiver operating characteristic analysis, pancreatic iron was the strongest discriminator between the two diseases. Left and right ventricular end-diastolic volume indexes were significantly higher in TI than in TM patients (p = 0.003 and p = 0.046, respectively), but the correction for the duration of regular transfusions removed the disease-specific differences (p > 0.05). Left ventricular (LV) mass index was significantly higher in TI (p = 0.049), while no difference (p > 0.05) was found in biventricular ejection fractions and replacement myocardial fibrosis. Conclusions: TI patients showed lower pancreatic and cardiac iron burden and more pronounced LV hypertrophy. These differences could not be explained by the different duration of the transfusional regimen.

Impact of the COVID-19 Pandemic on Iron Overload Assessment by MRI in Patients with Hemoglobinopathies: The E-MIOT Network Experience.

BACKGROUND: The E-MIOT (Extension-Myocardial Iron Overload in Thalassemia) project is an Italian Network assuring high-quality quantification of tissue iron overload by magnetic resonance imaging (MRI). We evaluated the impact of the COVID-19 pandemic on E-MIOT services. METHODS: The activity of the E-MIOT Network MRI centers in the year 2020 was compared with that of 2019. A survey evaluated whether the availability of MRI slots for patients with hemoglobinopathies was reduced and why. RESULTS: The total number of MRI scans was 656 in 2019 and 350 in 2020, with an overall decline of 46.4% (first MRI: 71.7%, follow-up MRI: 36.9%), a marked decline (86.9%) in the period March-June 2020, and a reduction in the gap between the two years in the period July-September. A new drop (41.4%) was recorded in the period October-December for two centers, due to the general reduction in the total amount of MRIs/day for sanitization procedures. In some centers, patients refused MRI scans for fear of getting COVID. Drops in the MRI services >80% were found for patients coming from a region without an active MRI site. CONCLUSIONS: The COVID-19 pandemic had a strong negative impact on MRI multi-organ iron quantification, with a worsening in the management of patients with hemoglobinopathies.

The Link of Pancreatic Iron with Glucose Metabolism and Cardiac Iron in Thalassemia Intermedia: A Large, Multicenter Observational Study.

In thalassemia major, pancreatic iron was demonstrated as a powerful predictor not only for the alterations of glucose metabolism but also for cardiac iron, fibrosis, and complications, supporting a profound link between pancreatic iron and heart disease. We determined for the first time the prevalence of pancreatic iron overload (IO) in thalassemia intermedia (TI) and systematically explored the link between pancreas T2* values and glucose metabolism and cardiac outcomes. We considered 221 beta-TI patients (53.2% females, 42.95 ± 13.74 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia project. Magnetic Resonance Imaging was used to quantify IO (T2* technique) and biventricular function and to detect replacement myocardial fibrosis. The glucose metabolism was assessed by the oral glucose tolerance test (OGTT). Pancreatic IO was more frequent in regularly transfused (N = 145) than in nontransfused patients (67.6% vs. 31.6%; p < 0.0001). In the regular transfused group, splenectomy and hepatitis C virus infection were both associated with high pancreatic siderosis. Patients with normal glucose metabolism showed significantly higher global pancreas T2* values than patients with altered OGTT. A pancreas T2* < 17.9 ms predicted an abnormal OGTT. A normal pancreas T2* value showed a 100% negative predictive value for cardiac iron. Pancreas T2* values were not associated to biventricular function, replacement myocardial fibrosis, or cardiac complications. Our findings suggest that in the presence of pancreatic IO, it would be prudent to initiate or intensify iron chelation therapy to prospectively prevent both disturbances of glucose metabolism and cardiac iron accumulation.