She Dejun, Liu Jianyi, Zeng Z, Xing Z, Cao Dairong
Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, 350005, Fuzhou, Fujian, People's Republic of China.
Department of Medical Imaging Technology, College of Medical Technology and Engineering, Fujian Medical University, 350108, Fuzhou, Fujian, People's Republic of China.
Neuroradiology. 2018 Jul;60(7):725-733. doi: 10.1007/s00234-018-2036-y. Epub 2018 May 24.
Supratentorial pilocytic astrocytoma (PA) may mimic pleomorphic xanthoastrocytoma (PXA) on conventional MR imaging, and a differentiation is clinically important because of distinct recurrence rate and anaplastic transformation rate. The purpose of this study was to investigate the diagnostic potential of diffusion-weighted imaging (DWI) in differentiating supratentorial PA from PXA.
We retrospectively reviewed DWI and conventional MR imaging of 16 patients with supratentorial PA and 8 patients with PXA. Variables of mean ADC values (ADC) and minimum ADC values (ADC) were calculated from the ROIs containing the contrast-enhancing lesion on DWI. ADC values and ADC values were compared among all supratentorial PA and PXA as well as between the subgroup of lobar PA and PXA by using an unpaired Student's t test. The optimum threshold, sensitivity, specificity, accuracy, and the area under the receiver operating characteristic curve (AUC) were determined.
Both ADC values (1542 ± 186 vs 1084 ± 201 × 10 mm/s; P < 0.001) and ADC values (1355 ± 183 vs 988 ± 180 × 10 mm/s; P < 0.001) were significantly higher in supratentorial PA compared with PXA. The ADC values and ADC values were also significantly higher in lobar PA than those in PXA. The ADC values were useful for differentiating supratentorial PA from PXA, with a threshold value of > 1189.8 × 10 mm/s (sensitivity, 93.8%; specificity, 100%). The optimal threshold values of > 1189.8 × 10 mm/s for ADC values provide sensitivity and specificity of 85.7 and 100%, respectively, for discriminating lobar PA from PXA. The optimum threshold value for ADC was > 1063.5 × 10 mm/s.
DWI is helpful in characterization and differentiation of supratentorial PA from PXA.
幕上毛细胞型星形细胞瘤（PA）在传统磁共振成像上可能类似多形性黄色星形细胞瘤（PXA），由于复发率和间变转化率不同，两者的鉴别在临床上具有重要意义。本研究的目的是探讨扩散加权成像（DWI）在鉴别幕上PA与PXA方面的诊断潜力。
我们回顾性分析了16例幕上PA患者和8例PXA患者的DWI及传统磁共振成像。从DWI上包含强化病变的感兴趣区（ROI）计算平均表观扩散系数（ADC）值和最小ADC值。采用独立样本t检验比较所有幕上PA和PXA以及叶性PA和PXA亚组之间的ADC值和最小ADC值。确定最佳阈值、敏感性、特异性、准确性和受试者操作特征曲线下面积（AUC）。
幕上PA的ADC值（1542±186 vs 1084±201×10⁻⁶mm²/s；P<0.001）和最小ADC值（1355±183 vs 988±180×10⁻⁶mm²/s；P<0.001）均显著高于PXA。叶性PA的ADC值和最小ADC值也显著高于PXA。ADC值有助于鉴别幕上PA与PXA，阈值>1189.8×10⁻⁶mm²/s（敏感性93.8%；特异性100%）。ADC值>1189.8×10⁻⁶mm²/s的最佳阈值鉴别叶性PA与PXA的敏感性和特异性分别为85.7%和100%。ADC的最佳阈值>1063.5×10⁻⁶mm²/s。
DWI有助于幕上PA与PXA的特征性表现及鉴别诊断。
