Finelli D A, Hurst G C, Gullapalli R P
Department of Radiology, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44109, USA.
AJNR Am J Neuroradiol. 1998 Jan;19(1):59-64.
We developed and evaluated clinically T1-weighted three-dimensional gradient-echo magnetization transfer (MT) sequences for contrast-enhanced MR imaging of the brain.
A short-repetition-time, radio frequency-spoiled, 3-D sequence was developed with a 10-millisecond MT pulse at high MT power and narrow MT pulse-frequency offset, and the enhancing lesion-to-normal white matter background (L/B) and the contrast-to-noise (C/N) ratios on these images were compared with those on T1-weighted spin-echo images and on non-MT 3-D gradient-echo images in a prospective study of 45 patients with 62 enhancing lesions. In the 24 patients who had intracranial metastatic disease, the number of lesions was counted and compared on the three types of images.
The MT ratio of normal callosal white matter was 55% on the MT 3-D gradient-echo sequences. The L/B and C/N on the MT 3-D gradient-echo images were more than double those on the 3-D gradient-echo images, and were significantly greater than those on the T1-weighted spin-echo images. In patients with metastatic disease, the MT 3-D gradient-echo images showed significantly more lesions than did the T1-weighted spin-echo or 3-D gradient-echo images.
MT 3-D gradient-echo MR imaging improves the contrast between enhancing lesion and background white matter over that obtained with conventional T1-weighted 3-D gradient-echo and spin-echo imaging. MT 3-D gradient-echo imaging provides practical sampling, image coverage, and spatial resolution, attributes that may be advantageous over MT T1-weighted spin-echo techniques.
我们研发并临床评估了用于脑部对比增强磁共振成像的T1加权三维梯度回波磁化传递（MT）序列。
研发了一种短重复时间、射频扰相的三维序列，其具有高MT功率和窄MT脉冲频率偏移的10毫秒MT脉冲，并在一项对45例患者的62个强化病灶进行的前瞻性研究中，将这些图像上的强化病灶与正常白质背景（L/B）及对比噪声比（C/N）与T1加权自旋回波图像和非MT三维梯度回波图像上的进行比较。在24例患有颅内转移疾病的患者中，对三种类型图像上的病灶数量进行计数和比较。
在MT三维梯度回波序列上，正常胼胝体白质的MT比率为55%。MT三维梯度回波图像上的L/B和C/N比三维梯度回波图像上的高出一倍多，且显著高于T1加权自旋回波图像上的。在患有转移疾病的患者中，MT三维梯度回波图像显示的病灶明显多于T1加权自旋回波图像或三维梯度回波图像。
与传统T1加权三维梯度回波和自旋回波成像相比，MT三维梯度回波磁共振成像提高了强化病灶与背景白质之间的对比度。MT三维梯度回波成像提供了实用的采样、图像覆盖范围和空间分辨率，这些特性可能比MT T1加权自旋回波技术更具优势。
