Association of hepatic/pancreatic iron overload evaluated by quantitative T2* MRI with bone mineral density and trabecular bone score

Abstract

Background Iron-overloaded patients are recognized as presenting an increased risk of osteoporosis. However, studies on the correlation between osteoporosis and organ iron overload are controversial or scarce. The aim of this study is to assess bone mineral density (BMD) and trabecular bone score (TBS) in correlation with hepatic and pancreatic iron overload. Methods Forty-one patients diagnosed with hemoglobinopathies, were studied. BMDs of the lumbar spine (LS), femoral neck (FN), and total hip (TH) were analyzed by Dual-energy X-ray absorptiometry (DXA) scan. LS bone quality was derived from each spine DXA examination using the TBS analysis. Hepatic and pancreatic iron overload were obtained with a multi-echo gradient echo T2* technique. Results Abnormal microarchitecture and abnormal bone mass were observed in 19/41 (46.3%) and 9/41 (22.0%) patients, respectively. For 26 males, BMD, T-score and Z-score of LS were significantly lower among subjects with moderate-severe hepatic iron-overload than their counterparts, as it is between no- and pancreatic iron-overload groups. For 15 females, patients with moderate-severe hepatic iron-overload had significantly lower BMD and T-score of FN and TH, and patients with pancreatic iron-overload had significantly lower BMD, T-score of FN, and lower BMD, T-score and Z-score of TH than their counterparts. Moreover, pancreatic T2*-value was positively correlated with BMD and T-score at all analyzed sites and Z-score at TH. Conclusion These data showed lower bone mass in patients with organ iron overload, particularly for LS in males, FN and TH in females. TBS may well represent a complementary tool for the evaluation of bone quality and the risk of fracture in iron-overloaded patients.

Narrative review of magnetic resonance imaging in quantifying liver iron load

“…At present, many studies have shown that T 2 * /R 2 * relaxation quantitative methods have good linear correlation when measuring LIC at 1.5 T and 3 T. T 2 * is negatively correlated with LIC. R 2 * is positively correlated with LIC and has shown excellent agreement and reproducibility ( 1 , 4 , 5 , 22 , 23 , 27 , 29 ), and this measurement has become a reliable quantitative assessment of liver iron overload. Figure 1 from Xu et al ( 4 ) shows liver T 2 * measured by different software.…”

“…With SE and GRE sequences, based on the influence of iron, the transverse relaxation of proton magnetization in water becomes faster, resulting in attenuation of magnetic resonance signal intensity, and T 2 and T 2 * weighted imaging are obtained, respectively. Then the corresponding signal decay time constants T 2 and T 2 * and the corresponding relaxation rates R 2 (1,000/T 2 ) and R 2 * (1,000/T 2 * ) were obtained ( 1 , 3 , 22 ). Relaxometry is a quantitative assessment of MRI signal loss caused by the shortening of T 2 /T 2 * relaxation times ( 21 , 22 ).…”

“…Then the corresponding signal decay time constants T 2 and T 2 * and the corresponding relaxation rates R 2 (1,000/T 2 ) and R 2 * (1,000/T 2 * ) were obtained ( 1 , 3 , 22 ). Relaxometry is a quantitative assessment of MRI signal loss caused by the shortening of T 2 /T 2 * relaxation times ( 21 , 22 ). Excess iron stored in the body in the form of trivalent iron can shorten T1 and T 2 —as T1 shortens, the corresponding SI increases; The corresponding SI decreases with the shortening of T 2 ( 1 , 3 ).…”

“…SWI has become a widely used imaging diagnostic technique in clinical practice, which is often used for the differential diagnosis of cerebral hemorrhage, intracerebral microvascular hemorrhage and intracranial calcification. This technique is based on quantitative measurement of tissue signal values and semi-quantitative measurement of corresponding iron content, which can improve its sensitivity to iron ( 3 , 22 , 45 ). With the continuous application of MRI technology in the detection of iron overload, the application of SWI in the study of liver iron overload is also increasing.…”

Gastrointestinal health and serum proteins are associated with BMD in postmenopausal women: A cross-sectional study

“…Patients who had less than one year of menopause, secondary osteoporosis, or recent use of medications that may affect bone metabolism (such as thiazolidinediones, immunosuppressants, systemic glucocorticoids, or hormone replacement therapy) were excluded. According to the standards of the World Health Organization (WHO) [15], the subjects were divided into three groups according to their BMD status: the normal group (T≥-1), the osteopenia group (-2.5 < T < -1) and the osteoporosis group (T≤-2.5) (Fig. 1).…”