利用自旋回波平面成像T_2加权序列提高肝脏实性病变的检出率

Improved detection of hepatic solid lesions with spin echo echo planar imaging(SE EPI)T_2 weighted sequences

目的 评价自旋回波平面成像 (SE EPI)T2 W序列对肝脏实性病变的检出能力。方法74例病人 (2 0 2个病灶 )接受肝脏 3种SE EPIT2 W序列磁共振扫描 ,评价其图像信噪比 (SNR)、肝脾对比噪声比 (L SCNR)、病灶对比噪声比 (CNR)及病变检出率 ,并与真实稳态进动快速成像 (true FISP)、快速自旋回波 (TSE)及半傅立叶采集单次激发快速自旋回波 (HASTE)等屏气T2 W序列相比较。结果SE EPI的SNR高于TSE (P <0 0 5 ) ,与true FISP相近 (P >0 0 5 ) ,但低于HASTE(P <0 0 1)。SE EPI序列的L SCNR及实性病变的CNR均显著高于true FISP、HASTE及TSE(P <0 0 1)。对于囊性病变 ,各序列间的检出率无明显差异 (P >0 0 5 )。各序列均检出所有直径大于 5cm的实性病变。直径 2～ 5cm的实性病变 ,SE EPI序列的检出率略高于true FISP、HASTE及TSE ,但无显著性差异 (P >0 0 5 )。直径小于 2cm的实性病灶 ,SE EPI序列的检出率 (93 9% )明显高于true FISP(5 7 6 % )、HASTE(71 2 % )及TSE(6 8 2 % ) (P <0 0 1)。结论 与其他屏气T2 W序列相比 ,SE EPIT2 WI有较高的病灶对比 。

Objective To evaluate the role of SE EPI T 2W in the detection of hepatic solid lesions. Methods Three SE EPI T 2W sequences were performed in 74 patients with 202 lesions. The signal to noise ratio(SNR), liver to spleen contrast to noise ratio (L S CNR), lesion CNR, and detection ratio of lesions were measured. The results were compared with those from true FISP, TSE and HASTE T 2WI. Results SNR of SE EPI T 2W sequences was higher than that of TSE( P <0.05), approaching that of true FISP( P >0.05), but lower than that of HASTE( P <0.01). The L S CNR and CNR of solid lesions in SE EPI sequences were significantly higher than those in other T 2W sequences ( P <0.01). No differences existed between these sequences in detecting cystic lesions ( P >0.05). Every sequence detected all solid lesions larger than 5 cm. SE EPI just detected little more solid lesions between 2 and 5 cm than other sequences. For solid lesions smaller than 2 cm, SE EPI showed higher detection rate (93.9%) than true FISP (57.6%), HASTE (71.2%) or TSE (68 2%) ( P <0.01). Conclusion Compared with other breath hold T 2W sequences, SE EPI T 2W has better lesion contrast, and can improve the detection of hepatic solid lesions.