Ho Chang Y, Cardinal Jeremy S, Kamer Aaron P, Kralik Stephen F
Department of Radiology, MRI Department, Indiana University School of Medicine, 705 Riley Hospital Drive, Indianapolis, IN, 46202, USA,
Neuroradiology. 2015 Mar;57(3):299-306. doi: 10.1007/s00234-014-1478-0. Epub 2014 Dec 13.
The aim of this study is to evaluate the utility of relative cerebral blood volume (rCBV) data from dynamic susceptibility contrast (DSC) perfusion in grading pediatric primary brain tumors.
A retrospective blinded review of 63 pediatric brain tumors with DSC perfusion was performed independently by two neuroradiologists. A diagnosis of low- versus high-grade tumor was obtained from conventional imaging alone. Maximum rCBV (rCBVmax) was measured from manual ROI placement for each reviewer and averaged. Whole-tumor CBV data was obtained from a semi-automated approach. Results from all three analyses were compared to WHO grade.
Based on conventional MRI, the two reviewers had a concordance rate of 81% (k = 0.62). Compared to WHO grade, the concordant cases accurately diagnosed high versus low grade in 82%. A positive correlation was demonstrated between manual rCBVmax and tumor grade (r = 0.30, P = 0.015). ROC analysis of rCBVmax (area under curve 0.65, 0.52-0.77, P = 0.03) gave a low-high threshold of 1.38 with sensitivity of 92% (74-99%), specificity of 40% (24-57%), NPV of 88% (62-98%), and PPV of 50% (35-65%) Using this threshold on 12 discordant tumors between evaluators from conventional imaging yielded correct diagnoses in nine patients. Semi-automated analysis demonstrated statistically significant differences between low- and high-grade tumors for multiple metrics including average rCBV (P = 0.027).
Despite significant positive correlation with tumor grade, rCBV from pediatric brain tumors demonstrates limited specificity, but high NPV in excluding high-grade neoplasms. In selective patients whose conventional imaging is nonspecific, an rCBV threshold may have further diagnostic value.
本研究的目的是评估动态磁敏感对比（DSC）灌注获得的相对脑血容量（rCBV）数据在小儿原发性脑肿瘤分级中的应用价值。
由两名神经放射科医生独立对63例有DSC灌注的小儿脑肿瘤进行回顾性盲法分析。仅通过传统影像获得肿瘤低级别与高级别的诊断。每位观察者通过手动放置感兴趣区（ROI）测量最大rCBV（rCBVmax）并求平均值。通过半自动方法获得全肿瘤CBV数据。将这三种分析的结果与世界卫生组织（WHO）分级进行比较。
基于传统MRI，两位观察者的一致率为81%（κ = 0.62）。与WHO分级相比，一致的病例中82%准确诊断出高级别与低级别肿瘤。手动测量的rCBVmax与肿瘤分级呈正相关（r = 0.30，P = 0.015）。rCBVmax的ROC分析（曲线下面积0.65，0.52 - 0.77，P = 0.03）得出低 - 高阈值为1.38，敏感性为92%（74 - 99%），特异性为40%（24 - 57%），阴性预测值为88%（62 - 98%），阳性预测值为50%（35 - 65%）。使用该阈值对传统影像评估者之间的12例不一致肿瘤进行分析，9例患者得到正确诊断。半自动分析显示，包括平均rCBV在内多个指标在低级别和高级别肿瘤之间存在统计学显著差异（P = 0.027）。
尽管与肿瘤分级有显著正相关，但小儿脑肿瘤的rCBV特异性有限，但在排除高级别肿瘤方面有较高的阴性预测值。在传统影像不具特异性的选择性患者中，rCBV阈值可能具有进一步的诊断价值。
