T2 relaxation time study of iron overload in b-thalassemia

Abstract

Myocardial iron deposition occurs as a result of blood transfusion therapy in b-thalassemia major patients. Since this deposition causes various cardiac complications, it is of interest to assess the iron content of the myocardium in relation to the clinical picture of the patients. Two different MRI indices were used to achieve this purpose: the T2 relaxation time and the heart/skeletal muscle signal intensity ratio. ECG gated spin echo images were obtained from 54 adult thalassemic patients, with a mean age of 26 (18-44) years, at TE = 22 ms and 60 ms, using a 1.5 T system. Patients were divided into 2 groups (A and B), according to their serum ferritin levels (> or < 2000 ng ml(-1)). Results were compared with nine controls, with a mean age of 25 (18-43) years. Heart T2 relaxation time in controls (44.3 +/- 3.5 ms) was higher than in group A (29.9 +/- 5.7 ms, P < 0.001) and group B (33.4 +/- 6.8 ms, P < 0.01). T2 was measurable in 66% of group A and 83% of group B patients. The heart/muscle signal intensity ratio in group A (0.45 +/- 0.27) was lower than in group B (0.82 +/- 0.33, P < 0.001) and the controls (1.15 +/- 0.20, P < 0.001). The heart/muscle signal intensity ratio was measurable in 94% of the patients and demonstrated an inverse relationship with the serum ferritin levels (r = -0.52, P < 0.01). This study indicates that the heart/muscle ratio is a sensitive index of iron overload and it can be measured in the majority of patients, irrespective of tissue iron concentration, thereby offering an advantage over the use of T2 relaxation time.

Transient elastography in the assessment of liver fibrosis in adult thalassemia patients

“…A possible limitation of this paper is related to the lack of liver biopsy in most patients. According to current clinical practice, however, this procedure is limited to only HCV viremic patients mainly in order to define the degree of both necroinflammation and fibrosis, as the recent introduction of valid non invasive technique (such as T2* MRI) allows us to precisely define the amount of iron overload [28][29][30].…”

“…De Gasperis'' at Niguarda Ca' Granda Hospital in Milan. Cardiac T2*, cardiac function, and liver T2* were assessed using validated techniques [28,29]. Patients were scanned with 1.5-T Magnetom Avanto Siemens; each scan lasted 20 min and included heart and liver T2* assessment with gradient-echo sequences and biventricular function evaluation with steady-state free procession (true-FISP) sequences.…”

Influence of myocardial fibrosis and blood oxygenation on heart T2* values in thalassemia patients

“…In particular, iron overload in MRI is associated with an effect termed susceptibility-induced relaxation (31). The iron, when present in an intracellular location in the form of ferritin and hemosiderin, causes magnetic inhomogeneities that result in a considerable quickening of protons transverse relaxation time (6), which can be assessed by spin-echo (T2) techniques (32,33) or gradient-echo (T2*) techniques (7,10). The gradient-echo T2* technique is generally used in the clinical arena.…”

Transition of Thalassaemia and Friedreich ataxia from fatal to chronic diseases

“…Iron chelation therapy is widely available for both the use of DF and L1 and also in many cases for DFRA in different countries including Cyprus [51] . The T2 and T2* relaxation time magnetic resonance imaging techniques have been used over the past decade for the routine diagnosis of excess iron load in the liver, the heart and also other organs [52][53][54][55][56] . Monitoring of serum ferritin levels is also routinely used for estimating body iron overload.…”