[用于颅内肿瘤放疗靶区定义的T1加权序列形态学磁共振成像。与快速扰相梯度回波序列和自旋回波序列的比较]
[Morphologic MR imaging with T1-weighted sequences for radiotherapy goal volume definition of intracranial tumors. Comparison with FLASH-Turbo-FLASH and SE sequences].
作者信息
Hawighorst H, Knopp M V, Debus J, Brix G, Engenhart-Cabillic R, Schad L R, Grandy M, Essig M, van Kaick G
机构信息
Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum, Heidelberg.
出版信息
Radiologe. 1997 Mar;37(3):243-50. doi: 10.1007/s001170050206.
INTRODUCTION
The goal of this study was to compare contrast-enhanced T1-weighted Flash and Turbo-Flash sequences with conventional spin-echo sequences as a basis for planning high-precision radiotherapy.
METHODS
A total of 25 consecutive patients with different intracranial tumors and a disrupted blood-brain barrier were studied. T1-weighted Flash, Turbo-Flash and conventional spin-echo images were evaluated after controlled 30-s infusion of 0.1 mmol/kg body weight of Gd-DTPA. The evaluation of the three sequences included the measurement of the spinal- and contrast-to-noise ratios, the visual inspection of the tumors and artifacts, and the measurement of tumor size.
RESULTS
The signal- and contrast-to-noise ratios were significantly (P < 0.05-0.01) lower for Flash and Turbo-Flash than for conventional spin-echo sequences. However, visual inspection of the contrast-enhancing tumors revealed in 23 and 24 of 25 lesions on Flash and Turbo-Flash images, respectively, good or very good tumor visibility when compared with conventional spin-echo images with a reduction of imaging time by a factor of 7-8. Flash and Turbo-Flash sequences were more prone to susceptibility artifacts, conventional spin-echo sequences more to pulsation artifacts in the posterior fossa. Tumor sizes were comparable in all three techniques.
CONCLUSION
At present, conventional spin-echo images are superior to fast Flash and ultrafast Turbo-Flash sequences as a basis for accurate target volume definition in high-precision radiotherapy. However, fast Flash and Turbo-Flash images may be a practicable alternative to conventional spin-echo images for tumors in the posterior fossa or in patients unable to tolerate a stereotactic fixation device. Despite some limitations, Turbo-Flash sequences enable fast dynamic MR imaging combined with an acceptable morphology, which may be sufficient to target volume planning in high-precision radiotherapy.
引言
本研究的目的是比较对比增强T1加权快速小角度激发序列（Flash）和快速自旋回波序列（Turbo-Flash）与传统自旋回波序列，为高精度放射治疗计划提供依据。
方法
共研究了25例连续的不同颅内肿瘤且血脑屏障破坏的患者。在以0.1 mmol/kg体重的钆喷酸葡胺（Gd-DTPA）进行30秒的控制输注后，对T1加权Flash、Turbo-Flash和传统自旋回波图像进行评估。对这三种序列的评估包括测量脊髓和对比噪声比、对肿瘤和伪影进行视觉检查以及测量肿瘤大小。
结果
Flash和Turbo-Flash序列的信号噪声比和对比噪声比显著低于传统自旋回波序列（P < 0.05 - 0.01）。然而，对增强肿瘤的视觉检查显示，与传统自旋回波图像相比，Flash和Turbo-Flash图像上25个病变中的23个和24个分别具有良好或非常好的肿瘤可见性，且成像时间减少了7 - 8倍。Flash和Turbo-Flash序列更容易出现磁敏感伪影，传统自旋回波序列在后颅窝更容易出现搏动伪影。在所有三种技术中肿瘤大小相当。
结论
目前，在高精度放射治疗中，作为精确靶区体积定义的基础，传统自旋回波图像优于快速Flash和超快Turbo-Flash序列。然而，对于后颅窝肿瘤或无法耐受立体定向固定装置的患者，快速Flash和Turbo-Flash图像可能是传统自旋回波图像的可行替代方案。尽管存在一些局限性，但Turbo-Flash序列能够实现快速动态磁共振成像并结合可接受的形态，这对于高精度放射治疗中的靶区体积规划可能就足够了。
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