IDEAL序列与频率选择预饱和脂肪抑制在乳腺MR中的对比研究

Comparative study between IDEAL and frequency-selective fat saturation in breast MRI

目的 :对比研究IDEAL序列和频率选择预饱和脂肪抑制方法的信噪比(signal to noise ratio,SNR)、对比噪声比(contrast to noise ratio,CNR)和脂肪抑制的均匀性,以明确IDEAL序列在乳腺MR成像中的优缺点。方法:选取19名行乳腺MR检查的患者,选择病变相同的层面测量SNR和CNR;对2种脂肪抑制方法所得图像选择相同层面的20个相同感兴趣区,测量皮下脂肪的信号值,并绘图进行比较。结果:IDEAL序列的SNR=7.159±0.279,频率选择预饱和脂肪抑制的SNR=5.012±0.243(P=0.000);IDEAL序列的CNR=24.643±1.598,频率选择预饱和脂肪抑制的CNR=21.832±2.096(P=0.031)。IDEAL序列的信号空间分布曲线形态平缓,频率选择预饱和脂肪抑制的信号空间分布曲线形态陡峭。结论:IDEAL序列具有良好的信噪比、对比噪声比和脂肪抑制均匀性,可作为乳腺MRI检查的首选序列。

Objective To investigate the advantages and disadvantages of IDEAL in breast MR imaging by comparing values of Signal to Noise Ratio（SNR）, Contrast to Noise Ratio（CNR） and uniformity between fat saturation of IDEAL and frequency-selective fat saturation. Methods Nineteen female patients were examined using a GE 1.5T MR. SNR and CNR were calculated on the same slice of lesions in breast. The region of interest（ROI） of subcutaneous fat in 20 equal installments were measured in two methods of fat saturation. Signal-spatial location curves were drawn according to the SI in different locations. Comparative analysis of SNR, CNR and Uniformity of fat saturation was processed by SPSS 13.0software package. Results The SNR of sequence IDEAL and frequency-selective fat saturation were 7.159 ±0.279 and5.012±0.243（P=0.000）. The CNR of sequence IDEAL and frequency-selective fat saturation were 24.643 ±1.598 and21.832±2.096（P=0.031）. The curve pattern of IDEAL was mild while frequency-selective fat saturation was steep. Conclusion Sequence IDEAL has the advantages of high SNR, CNR and uniformity of fat saturation in breast MRI. IDEAL can be the first choice of breast MR imaging.