Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
Magn Reson Med Sci. 2011;10(4):229-37. doi: 10.2463/mrms.10.229.
Multiple small-animal magnetic resonance (MR) imaging to measure tumor volume may increase the throughput of preclinical cancer research assessing tumor response to novel therapies. We used a clinical scanner and multi-channel coil to evaluate the usefulness of this imaging to assess experimental tumor volume in mice.
We performed a phantom study to assess 2-dimensional (2D) geometric distortion using 9-cm spherical and 32-cell (8×4 one-cm(2) grids) phantoms using a 3-tesla clinical MR scanner and dedicated multi-channel coil composed of 16 5-cm circular coils. Employing the multi-channel coil, we simultaneously scanned 6 or 8 mice bearing sarcoma 180 tumors. We estimated tumor volume from the sum of the product of tumor area and slice thickness on 2D spin-echo images (repetition time/echo time, 3500/16 ms; in-plane resolution, 0.195×0.195×1 mm(3)). After MR acquisition, we excised and weighed tumors, calculated reference tumor volumes from actual tumor weight assuming a density of 1.05 g/cm(3), and assessed the correlation between the estimated and reference volumes using Pearson's test.
Two-dimensional geometric distortion was acceptable below 5% in the 9-cm spherical phantom and in every cell in the 32-cell phantom. We scanned up to 8 mice simultaneously using the multi-channel coil and found 11 tumors larger than 0.1 g in 12 mice. Tumor volumes were 1.04±0.73 estimated by MR imaging and 1.04±0.80 cm(3) by reference volume (average±standard deviation) and highly correlated (correlation coefficient, 0.995; P<0.01, Pearson's test).
Use of multiple small-animal MR imaging employing a clinical scanner and multi-channel coil enabled accurate assessment of experimental tumor volume in a large number of mice and may facilitate high throughput monitoring of tumor response to therapy in preclinical research.
采用多台小动物磁共振（MR）成像仪来测量肿瘤体积，可能会增加评估新型疗法对肿瘤疗效的临床前癌症研究的通量。我们使用临床型磁共振扫描仪和多通道线圈来评估这种成像方法对评估小鼠实验性肿瘤体积的实用性。
我们使用 3T 临床型磁共振扫描仪和由 16 个 5cm 圆形线圈组成的专用多通道线圈，在 9cm 球形和 32 细胞（8×4 个 1cm2 网格）体模中进行了二维（2D）几何变形的体模研究。使用多通道线圈，我们同时扫描了 6 或 8 只患有肉瘤 180 肿瘤的小鼠。我们根据 2D 自旋回波图像上肿瘤面积与层面厚度的乘积（重复时间/回波时间，3500/16ms；平面分辨率，0.195×0.195×1mm3）来估计肿瘤体积。在 MR 采集后，我们切除并称重肿瘤，根据假设的密度为 1.05g/cm3 计算参考肿瘤体积，并通过 Pearson 检验评估估计体积与参考体积之间的相关性。
在 9cm 球形体模中，2D 几何变形小于 5%，在 32 细胞体模中的每个细胞中都可接受。我们使用多通道线圈同时扫描了 8 只小鼠，在 12 只小鼠中发现了 11 个大于 0.1g 的肿瘤。通过 MR 成像估计肿瘤体积为 1.04±0.73cm3，通过参考体积（平均值±标准差）估计为 1.04±0.80cm3，两者高度相关（相关系数为 0.995；P<0.01，Pearson 检验）。
使用临床型磁共振扫描仪和多通道线圈进行多台小动物 MR 成像，可实现对大量小鼠实验性肿瘤体积的准确评估，可能有助于在临床前研究中实现高通量监测肿瘤对治疗的反应。
