Koral Korgün, Alford Raphael, Choudhury Nabila, Mossa-Basha Mahmud, Gargan Lynn, Gimi Barjor, Gao Ang, Zhang Song, Bowers Daniel C, Koral Kadriye M, Izbudak Izlem
Department of Radiology, University of Texas Southwestern Medical Center and Children's Medical Center, 1935 Medical District Drive, Dallas, TX, 75235, USA,
Neuroradiology. 2014 Sep;56(9):781-8. doi: 10.1007/s00234-014-1398-z. Epub 2014 Jun 29.
The purpose of our study was to test the accuracy and applicability of decision rules utilizing apparent diffusion coefficient (ADC) ratios on accurate preoperative diagnosis of common pediatric cerebellar tumors across two institutions.
In this HIPAA-compliant, IRB-approved study, performed at two institutions, 140 pediatric cerebellar tumors were included. Two separate reviewers placed regions of interest on the solid components of 140 tumors (98 at site A and 42 at site B) and normal brain on the ADC maps. The third reviewer who was blinded to the histopathological diagnoses made the same measurements on 140 patients to validate the data. Tumor to normal brain ADC ratios were calculated. Receiver operator curve (ROC) analysis was performed to generate thresholds to discriminate tumors. Utility of decision rules based on these thresholds was tested.
While ADC values of medulloblastomas were different between the sites, there was no difference among the ADC ratios of medulloblastomas, pilocytic astrocytomas, ependymomas, and atypical teratoid rhabdoid tumors between the sites. ADC ratio of ≥1.8 correctly discriminated pilocytic astrocytomas from ependymomas with a sensitivity of 0.83 and a specificity of 0.78. ADC ratio of <1.2 correctly discriminated ependymomas from embryonal tumors with a sensitivity of 0.87 and a specificity of 0.83. The proposed decision rules correctly discriminated 120 of the 140 tumors (85.71%). Age ≥2 years criterion correctly sorted medulloblastomas in 84.48% of patients and age <2 years correctly distinguished atypical teratoid rhabdoid tumors in 90.00% of patients with embryonal tumors.
Decision rules based on ADC ratios are applicable across two institutions in the accurate preoperative diagnosis of common pediatric cerebellar tumors.
我们研究的目的是检验利用表观扩散系数（ADC）比值的决策规则在两个机构对常见小儿小脑肿瘤进行准确术前诊断的准确性和适用性。
在这项符合健康保险流通与责任法案（HIPAA）且经机构审查委员会（IRB）批准的研究中，于两个机构纳入了140例小儿小脑肿瘤。两名独立的审阅者在140个肿瘤（机构A有98个，机构B有42个）的实性成分以及ADC图上的正常脑组织上放置感兴趣区。对组织病理学诊断不知情的第三位审阅者对140例患者进行相同测量以验证数据。计算肿瘤与正常脑组织的ADC比值。进行受试者操作特征曲线（ROC）分析以生成区分肿瘤的阈值。测试基于这些阈值的决策规则的效用。
虽然两个机构间髓母细胞瘤的ADC值不同，但两个机构间髓母细胞瘤、毛细胞型星形细胞瘤、室管膜瘤和非典型畸胎样横纹肌样瘤的ADC比值并无差异。ADC比值≥1.8可正确区分毛细胞型星形细胞瘤与室管膜瘤，敏感性为0.83，特异性为0.78。ADC比值<1.2可正确区分室管膜瘤与胚胎性肿瘤，敏感性为0.87，特异性为0.83。所提出的决策规则正确区分了140个肿瘤中的120个（85.71%）。年龄≥2岁这一标准在84.48%的患者中正确区分了髓母细胞瘤，年龄<2岁在90.00%的胚胎性肿瘤患者中正确区分了非典型畸胎样横纹肌样瘤。
基于ADC比值的决策规则在两个机构对常见小儿小脑肿瘤进行准确术前诊断时是适用的。
