Winkler M L, Thoeni R F, Luh N, Kaufman L, Margulis A R
Radiologic Imaging Laboratory, University of California, San Francisco 94143.
Radiology. 1989 Mar;170(3 Pt 1):801-6. doi: 10.1148/radiology.170.3.2916032.
Twenty-seven patients with hepatic neoplasms were prospectively examined at 0.35 T with multisection magnetic resonance (MR) imaging during a single breath hold. The procedures included a spin-echo (SE) sequence with a repetition time (TR) of 250 or 125 msec and an echo time (TE) of 15 msec (TR/TE = 250 or 125/15) and gradient-echo (GRE) partial-flip sequences at 250 or 125/20 in phase and 250 or 125/12 out of phase (flip angle of 70 degrees). These procedures were compared with conventional multiacquisition sequences at SE 250/15 (n = 8) in the same patients. GRE partial-flip sequences with a large flip angle provided the optimum combination of contrast and signal-to-noise ratio for imaging hepatic neoplasms, with a signal-difference-to-noise ratio that for in-phase images was 93% greater and for out-of-phase images was 53% greater than that of the SE images. The use of in-phase TEs was preferable to maintain tissue contrast, and presaturation pulses were employed to eliminate vascular pulsation artifacts. All breath-hold procedures provided suppression of motion artifacts superior to that of the short TR, short TE multiacquisition SE imaging. Such sequences should become indispensable for MR imaging of the upper abdomen.
对27例肝脏肿瘤患者采用0.35T设备在单次屏气期间进行多层面磁共振（MR）成像的前瞻性检查。检查程序包括：自旋回波（SE）序列，重复时间（TR）为250或125毫秒，回波时间（TE）为15毫秒（TR/TE = 250或125/15），以及梯度回波（GRE）部分翻转序列，分别为同相位时250或125/20以及反相位时250或125/12（翻转角70度）。将这些检查程序与同一批患者的常规多采集序列（SE 250/15，n = 8）进行比较。大翻转角的GRE部分翻转序列为肝脏肿瘤成像提供了对比度和信噪比的最佳组合，同相位图像的信号差与噪声比比SE图像高93%，反相位图像高53%。采用同相位TE更有利于保持组织对比度，并采用预饱和脉冲消除血管搏动伪影。所有屏气检查程序对运动伪影的抑制均优于短TR、短TE多采集SE成像。这类序列应成为上腹部MR成像必不可少的方法。
