Thomsen C, Wiggers P, Ring-Larsen H, Christiansen E, Dalhøj J, Henriksen O, Christoffersen P
Danish Research Center of Magnetic Resonance, Hvidovre Hospital, Copenhagen.
Magn Reson Imaging. 1992;10(6):867-79. doi: 10.1016/0730-725x(92)90440-b.
A total of 4302 healthy blood donors were screened for elevated serum ferritin and transferrin saturation. Fifteen had increased serum ferritin at a follow-up examination. Five relatives of these donors also entered the study. Eleven patients had elevated liver iron concentrations, while five had normal liver iron concentrations. The R2 relaxation rate in the liver was first measured with a conventional multi-spin-echo imaging sequence, and then by a volume-selective spectroscopic multi-spin-echo sequence, in order to achieve a minimum echo time of 4 msec. No correlation was found between the relaxation rate R2 and the liver iron concentration, when R2 was calculated from the imaging data. Multi-exponential transverse relaxation could be resolved when the spectroscopic sequence was used. A strong correlation between the initial slope of the relaxation curve and the liver iron concentration was found (r = 0.90, p < 0.001). Signal intensity ratios between liver and muscle were calculated from the first three echoes in the multi-echo imaging sequence, and from a gradient echo sequence. A strong correlation between the logarithm of the signal intensity ratios and the liver iron concentration was found. Although both spectroscopic T2 relaxation time measurements and signal intensity ratios could be used to quantify liver iron concentration, the gradient echo imaging seemed to be the best choice. Gradient echo imaging could be performed during a single breath hold, so motion artifacts could be avoided. The accuracy of liver iron concentration estimates from signal intensity ratios in the gradient echo images was about 35%.
对总共4302名健康献血者进行了血清铁蛋白升高和转铁蛋白饱和度筛查。15人在随访检查时血清铁蛋白升高。这些献血者的5名亲属也进入了研究。11名患者肝脏铁浓度升高，而5名患者肝脏铁浓度正常。首先用传统的多自旋回波成像序列测量肝脏中的R2弛豫率，然后用体积选择性光谱多自旋回波序列测量，以实现最小回波时间为4毫秒。当从成像数据计算R2时，未发现弛豫率R2与肝脏铁浓度之间存在相关性。使用光谱序列时可分辨多指数横向弛豫。发现弛豫曲线的初始斜率与肝脏铁浓度之间存在强相关性（r = 0.90，p < 0.001）。从多回波成像序列的前三个回波以及梯度回波序列计算肝脏与肌肉之间的信号强度比。发现信号强度比的对数与肝脏铁浓度之间存在强相关性。尽管光谱T2弛豫时间测量和信号强度比均可用于量化肝脏铁浓度，但梯度回波成像似乎是最佳选择。梯度回波成像可在单次屏气期间进行，因此可避免运动伪影。从梯度回波图像中的信号强度比估计肝脏铁浓度的准确性约为35%。
