Absence of T1 Hyperintensity in the Brain of High-risk Patients After Multiple Administrations of High-dose Gadobutrol for Cardiac Magnetic Resonance

Phenotypic Clustering of Beta-Thalassemia Intermedia Patients Using Cardiovascular Magnetic Resonance

We employed an unsupervised clustering method that integrated demographic, clinical, and cardiac magnetic resonance (CMR) data to identify distinct phenogroups (PGs) of patients with beta-thalassemia intermedia (β-TI). We considered 138 β-TI patients consecutively enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) Network who underwent MR for the quantification of hepatic and cardiac iron overload (T2* technique), the assessment of biventricular size and function and atrial dimensions (cine images), and the detection of replacement myocardial fibrosis (late gadolinium enhancement technique). Three mutually exclusive phenogroups were identified based on unsupervised hierarchical clustering of principal components: PG1, women; PG2, patients with replacement myocardial fibrosis, increased biventricular volumes and masses, and lower left ventricular ejection fraction; and PG3, men without replacement myocardial fibrosis, but with increased biventricular volumes and masses and lower left ventricular ejection fraction. The hematochemical parameters and the hepatic and cardiac iron levels did not contribute to the PG definition. PG2 exhibited a significantly higher risk of future cardiovascular events (heart failure, arrhythmias, and pulmonary hypertension) than PG1 (hazard ratio-HR = 10.5; p = 0.027) and PG3 (HR = 9.0; p = 0.038). Clustering emerged as a useful tool for risk stratification in TI, enabling the identification of three phenogroups with distinct clinical and prognostic characteristics.

Gadolinium deposition in the brain is related to various contrast agents: a matched case-control study

AIM

To assess the relationship between gadolinium deposition in the brain and various gadolinium-based contrast agents (GBCAs) and to explore confounding variables.

METHODS

The study group included 87 patients with multiple enhanced brain magnetic resonance imaging (MRI) examinations of which 48 patients were in the linear GBCA group (33 patients in gadopentetate dimeglumine group and 15 patients in gadobenate dimeglumine group) and 39 patients in the macrocyclic GBCA group (22 patients in gadobutrol group and 17 patients in gadoterate meglumine group). The control group included 87 normal participants who were matched regarding age, sex, MRI machine and imaging sequences to the study cohort. T1 signal intensity (SI) ratios of the dentate nucleus to the pons (DN/pons) and of the globus pallidus to the frontal white matter (GP/FWM) in both groups were calculated and compared. The relationships between SI ratios and confounding variables were analysed.

RESULTS

Significant differences were detected between two linear GBCA groups and control groups in T1 SI ratios of the DN/pons and GP/FWM (all p<0.001). There were no differences for two the macrocyclic GBCA groups compared with matching control groups (all p>0.05). T1 SI ratios of the linear GBCA group were significantly higher than those of the macrocyclic GBCA group (p<0.001). In the linear GBCA group, the T1 SI ratios of the DN/pons correlated moderately positively with the number of GBCA administrations (r=0.643, p<0.001), and MRI machine and sequence used.

CONCLUSIONS

Increased T1 SI could be observed after repeated administrations of linear GBCA. T1 SI of the DN correlated with the number of linear GBCA administrations, and detection might be affected by MRI machine and sequence.

National networking in rare diseases and reduction of cardiac burden in thalassemia major

AIMS

A tailored chelation therapy guided by magnetic resonance imaging (MRI) is a strategy to improve the prognosis in iron-loaded patients, in many cases still hampered by limited MRI availability. In order to address this issue, the Myocardial Iron Overload in Thalassemia (MIOT) network was established in Italy and we aimed to describe the impact of 10-year activity of this network on cardiac burden in thalassemia major (TM).

METHODS AND RESULTS

Within the MIOT network, 1746 TM patients (911 females; mean age 31.2 ± 9.1 years) were consecutively enrolled and prospectively followed by 70 thalassemia and 10 MRI centres. Patients were scanned using a multiparametric approach for assessing myocardial iron overload (MIO), biventricular function, and myocardial fibrosis. At the last MRI scan, a significant increase in global heart T2* values and a significantly higher frequency of patients with no MIO (all segmental T2* ≥20 ms) were detected, with a concordant improvement in biventricular function, particularly in patients with baseline global heart T2* <20 ms. Forty-seven percentage of patients changed the chelation regimen based on MRI. The frequency of heart failure (HF) significantly decreased after baseline MRI from 3.5 to 0.8% (P < 0.0001). Forty-six patients died during the study, and HF accounted for 34.8% of deaths.

CONCLUSION

Over 10 years, continuous monitoring of cardiac iron and a tailored chelation therapy allowed MIO reduction, with consequent improvement of cardiac function and reduction of cardiac complications and mortality from MIO-related HF. A national networking for rare diseases therefore proved effective in improving the care and reducing cardiac outcomes of TM patients.

KEY QUESTION

Which was the impact on cardiac outcomes in thalassemia major by a national network among thalassemia and magnetic resonance imaging centres ensuring the continuous and standardized monitoring of the cardiac iron levels?

KEY FINDING

There was a reduction of myocardial iron overload (MIO) in almost 70% of patients, with consequent improvement of cardiac function and reduction of cardiac complications and mortality from MIO-related heart failure.

TAKE HOME MESSAGE

A national clinical and imaging networking in rare diseases was effective in improving the care and in reducing the cardiac burden in thalassemia major patients.