Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
Clin Cancer Res. 2017 Jul 15;23(14):3667-3675. doi: 10.1158/1078-0432.CCR-16-2265. Epub 2017 Jan 17.
Stereotactic radiosurgery (SRS) is a common treatment used in patients with brain metastases and is associated with high rates of local control, however, at the risk of radiation necrosis. It is difficult to differentiate radiation necrosis from tumor progression using conventional MRI, making it a major diagnostic dilemma for practitioners. This prospective study investigated whether chemical exchange saturation transfer (CEST) was able to differentiate these two conditions. Sixteen patients with brain metastases who had been previously treated with SRS were included. Average time between SRS and evaluation was 12.6 months. Lesion type was determined by pathology in 9 patients and the other 7 were clinically followed. CEST imaging was performed on a 3T Philips scanner and the following CEST metrics were measured: amide proton transfer (APT), magnetization transfer (MT), magnetization transfer ratio (MTR), and area under the curve for CEST peaks corresponding to amide and nuclear Overhauser effect (NOE). Five lesions were classified as progressing tumor and 11 were classified as radiation necrosis (using histopathologic confirmation and radiographic follow-up). The best separation was obtained by NOE (NOE = 8.9 ± 0.9%, NOE = 12.6 ± 1.6%, < 0.0001) and Amide (Amide = 8.2 ± 1.0%, Amide = 12.0 ± 1.9%, < 0.0001). MT (MT = 4.7 ± 1.0%, MT = 6.7 ± 1.7%, = 0.009) and NOE (NOE = 4.3 ± 2.0% Hz, NOE = 7.2 ± 1.9% Hz, = 0.019) provided statistically significant separation but with higher values. CEST was capable of differentiating radiation necrosis from tumor progression in brain metastases. Both NOE and Amide provided statistically significant separation of the two cohorts. However, APT was unable to differentiate the two groups. .
立体定向放射外科（SRS）是一种常用于脑转移瘤患者的治疗方法，具有很高的局部控制率，但存在放射性坏死的风险。使用常规 MRI 很难区分放射性坏死和肿瘤进展，这对医生来说是一个主要的诊断难题。这项前瞻性研究旨在探讨化学交换饱和传递（CEST）是否能够区分这两种情况。16 例脑转移瘤患者曾接受 SRS 治疗，SRS 与评估之间的平均时间为 12.6 个月。9 例患者的病变类型由病理确定，其余 7 例患者进行临床随访。CEST 成像在 3T 飞利浦扫描仪上进行，测量以下 CEST 指标：酰胺质子转移（APT）、磁化转移（MT）、磁化转移比（MTR）和对应于酰胺和核 Overhauser 效应（NOE）的 CEST 峰的曲线下面积。5 个病灶被归类为进展性肿瘤，11 个病灶被归类为放射性坏死（使用组织病理学证实和影像学随访）。NOE（NOE = 8.9 ± 0.9%，NOE = 12.6 ± 1.6%，<0.0001）和酰胺（Amide = 8.2 ± 1.0%，Amide = 12.0 ± 1.9%，<0.0001）的分离效果最好。MT（MT = 4.7 ± 1.0%，MT = 6.7 ± 1.7%，= 0.009）和 NOE（NOE = 4.3 ± 2.0% Hz，NOE = 7.2 ± 1.9% Hz，= 0.019）提供了统计学上显著的分离，但值较高。CEST 能够区分脑转移瘤中的放射性坏死和肿瘤进展。NOE 和酰胺均能统计学上显著分离两组。然而，APT 无法区分两组。
