Thomson Chris B, Haynes Kevin H, Pluhar G Elizabeth
Am J Vet Res. 2016 May;77(5):471-7. doi: 10.2460/ajvr.77.5.471.
OBJECTIVE To compare the orthogonal diameter (visual metric) method against a manual perimeter tracing (planimetry) method to measure volume of brain tumors in dogs by use of MRI scans. SAMPLE 22 sets of MRI brain scans pertaining to 22 client-owned dogs with histologically confirmed glioma. PROCEDURES MRI scans were reviewed by 2 operators, and scans revealing tumors with a degree of gadolinium enhancement that allowed discrimination between tumor tissue and healthy parenchyma were used. Each operator calculated tumor volume for each set of scans twice by use of visual metric and planimetry methods. Inter- and intraoperator variability were assessed by calculation of an agreement index (AI). RESULTS Mean ± SD intraoperator AIs were 0.79 ± 0.24 for the visual metric method and 0.89 ± 0.17 for the planimetry method. Intraoperator variability for both operators was significantly less when the planimetry method was used than when the visual metric method was used. No significant differences were identified in mean interoperator AI between visual metric (0.68 ± 0.28) and planimetry (0.67 ± 0.31) methods. CONCLUSIONS AND CLINICAL RELEVANCE The lower intraoperator variability achieved with the planimetry versus visual metric method should result in more precise volume assessments when the same operator performs multiple volume measurements of brain tumors in dogs. Equivocal results for interoperator variability may have been due to method variance or inadequate preliminary training. Additional studies are needed to evaluate the suitability of planimetry for assessing response to treatment.
目的 比较正交直径(视觉测量)法与手动周长追踪(面积测量)法,通过磁共振成像(MRI)扫描测量犬脑肿瘤的体积。样本 22 组 MRI 脑部扫描图像,来自 22 只经组织学确诊为神经胶质瘤的客户拥有的犬。程序 2 名操作人员对 MRI 扫描图像进行评估,使用显示肿瘤有一定钆增强程度、能够区分肿瘤组织和健康实质的扫描图像。每位操作人员使用视觉测量法和面积测量法对每组扫描图像计算肿瘤体积两次。通过计算一致性指数(AI)评估操作人员间和操作人员内的变异性。结果 视觉测量法的操作人员内平均±标准差 AI 为 0.79±0.24,面积测量法为 0.89±0.17。使用面积测量法时,两名操作人员的操作人员内变异性均显著低于使用视觉测量法时。视觉测量法(0.68±0.28)和面积测量法(0.67±0.31)之间的操作人员间平均 AI 未发现显著差异。结论及临床意义 与视觉测量法相比,面积测量法实现的较低操作人员内变异性应能在同一操作人员对犬脑肿瘤进行多次体积测量时带来更精确的体积评估。操作人员间变异性的不确定结果可能是由于方法差异或初步培训不足。需要进一步研究来评估面积测量法评估治疗反应的适用性。