Department of Abdominal Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX.
Department of Abdominal Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX.
Brachytherapy. 2020 Jul-Aug;19(4):484-490. doi: 10.1016/j.brachy.2020.04.001. Epub 2020 May 10.
The purpose of this study was to compare an isotropic three-dimensional (3D) T2-weighted sequence sampling perfection with application-optimized contrasts by using flip angle evolution (SPACE) with an axial two-dimensional T2-weighted turbo spin echo (TSE) sequence with regard to overall image quality and the delineation of normal prostate and periprostatic anatomy for low-dose-rate prostate cancer brachytherapy planning evaluation.
Patients (n = 69) with prostate cancer who had pelvic magnetic resonance imaging (MRI) for low-dose-rate brachytherapy treatment planning were included. Three radiologists independently assessed the visibility of nine anatomic structures on each sequence by using a 5-point scale and overall image quality by using a 4-point scale. The significance of the differences in diagnostic performance was tested with a Wilcoxon signed rank test.
No significant intersequence differences were found for most (7/9) anatomical structures and overall image quality. The mean scores for visibility of anatomical structures on the 3D SPACE and 2D TSE sequences, respectively, were as follows: the zonal anatomy (3.7; 3.9, p = 0.05), prostate capsule (3.9; 4.0, p = 0.08), neurovascular bundle (2.9; 2.9, p = 0.9), rectoprostatic angle (3.8; 3.8, p = 0.35), rectum (4.2; 4.3, p = 0.26), urethra (3.8; 3.9, p = 0.12), urinary bladder (4.6; 4.6, p = 0.61), and overall image quality (2.9; 2.9, p = 0.33). 3D SPACE was superior for delineation of the genitourinary diaphragm (3.8; 3.6, p = 0.003), whereas 2D TSE was superior for delineation of the seminal vesicles (3.5; 4.0, p < 0.0001).
Anatomic delineation of the prostatic and periprostatic anatomy provided by the 3D SPACE sequence is as robust in quality as that provided by a conventional 2D TSE sequence with superior delineation of the genitourinary diaphragm. For MRI-based brachytherapy treatment planning, the 3D SPACE sequence with subcentimeter isotropic resolution can replace the 2D TSE sequence and be incorporated into standard MRI protocols.
本研究旨在比较各向同性三维（3D）T2 加权序列采样完美与应用优化对比翻转角演化（SPACE）与轴向二维 T2 加权涡轮自旋回波（TSE）序列在低剂量率前列腺癌近距离放射治疗计划评估中整体图像质量和正常前列腺及前列腺周围解剖结构的描绘方面的性能。
纳入了 69 例因低剂量率近距离放射治疗计划而进行盆腔磁共振成像（MRI）的前列腺癌患者。三位放射科医生分别使用 5 分制评估了两种序列中每个序列的 9 个解剖结构的可见性，并使用 4 分制评估了整体图像质量。采用 Wilcoxon 符号秩检验检验诊断性能差异的显著性。
大多数（7/9）解剖结构和整体图像质量在两种序列之间均无显著差异。3D SPACE 和 2D TSE 序列的解剖结构可见性平均得分分别为：分区解剖（3.7；3.9，p=0.05）、前列腺包膜（3.9；4.0，p=0.08）、神经血管束（2.9；2.9，p=0.9）、直肠前列腺角（3.8；3.8，p=0.35）、直肠（4.2；4.3，p=0.26）、尿道（3.8；3.9，p=0.12）、膀胱（4.6；4.6，p=0.61）和整体图像质量（2.9；2.9，p=0.33）。3D SPACE 对生殖膈的勾画优于 2D TSE（3.8；3.6，p=0.003），而 2D TSE 对精囊的勾画优于 3D SPACE（3.5；4.0，p＜0.0001）。
3D SPACE 序列提供的前列腺及前列腺周围解剖结构的解剖描绘质量与常规 2D TSE 序列一样可靠，且对生殖膈的描绘更优。对于基于 MRI 的近距离放射治疗计划，亚厘米各向同性分辨率的 3D SPACE 序列可以替代 2D TSE 序列并纳入标准 MRI 协议。
