Alexopoulou Efthymia, Stripeli Fotini, Baras Panagiotis, Seimenis Ioannis, Kattamis Antonis, Ladis Vasilis, Efstathopoulos Efstathios, Brountzos Elias N, Kelekis Alexis D, Kelekis Nikolaos L
Second Department of Radiology, National and Kapodistrian University of Athens, Athens, Greece.
J Magn Reson Imaging. 2006 Feb;23(2):163-70. doi: 10.1002/jmri.20489.
To evaluate the usefulness of a time-efficient MRI method for the quantitative determination of tissue iron in the liver and heart of beta-thalassemic patients using spin-spin relaxation rate, R2, measurements.
Images were obtained at 1.5 T from aqueous Gd-DTPA solutions (0.106-8 mM) and from the liver and heart of 46 beta-thalassemic patients and 10 controls. The imaging sequence used was a respiratory-triggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spin-echo (SE) pulse sequence (TR = 2000 msec, TE(min) = 5 msec, echo spacing (ES) = 5 msec, matrix = 192 x 256, slice thickness = 10 mm). Liver iron concentration (LIC) measurements were obtained for 22 patients through biopsy specimens excised from the relevant liver segment. Biopsy specimens were also evaluated regarding iron grade and fibrosis. Serum ferritin (SF) measurements were obtained in all patients.
A statistically significant difference was found between patients and healthy controls in mean liver (P < 0.004) and myocardium (P < 0.004) R2 values. The R2 values correlated well with Gd DTPA concentration (r = 0.996, P < 0.0001) and LIC (r = 0.874, P < 0.0001). A less significant relationship (r = 0.791, P < 0.0001) was found between LIC measurements and SF levels. R2 measurements appear to be significantly affected (P = 0.04) by different degrees of hepatic fibrosis. The patients' liver R2 values did not correlate with myocardial R2 values (r = 0.038, P < 0.21).
Tissue iron deposition in beta-thalassemic patients may be adequately quantified using R2 measurements obtained with a 16-echo MRI sequence with short ES (5 msec), even in patients with a relatively increased iron burden.
使用自旋-自旋弛豫率（R2）测量，评估一种省时的MRI方法在定量测定β地中海贫血患者肝脏和心脏组织铁含量方面的实用性。
在1.5T磁场下，从钆喷酸葡胺水溶液（0.106 - 8 mM）以及46例β地中海贫血患者和10例对照者的肝脏和心脏获取图像。所使用的成像序列是呼吸触发的16回波Carr-Purcell-Meiboom-Gill（CPMG）自旋回波（SE）脉冲序列（TR = 2000毫秒，TE（最小值）= 5毫秒，回波间隔（ES）= 5毫秒，矩阵 = 192×256，层厚 = 10毫米）。通过从相关肝段切除的活检标本，对22例患者进行肝脏铁浓度（LIC）测量。还对活检标本的铁分级和纤维化情况进行评估。对所有患者进行血清铁蛋白（SF）测量。
患者与健康对照者的肝脏（P < 0.004）和心肌（P < 0.004）平均R2值存在统计学显著差异。R2值与钆喷酸葡胺浓度（r = 0.996，P < 0.0001）和LIC（r = 0.874，P < 0.0001）相关性良好。LIC测量值与SF水平之间的关系较弱（r = 0.791，P < 0.0001）。不同程度的肝纤维化似乎对R2测量有显著影响（P = 0.04）。患者的肝脏R2值与心肌R2值不相关（r = 0.038，P < 0.21）。
即使在铁负荷相对增加的患者中，使用具有短ES（5毫秒）的16回波MRI序列获得的R2测量值，也可充分定量β地中海贫血患者的组织铁沉积。
