Nabavizadeh S A, Assadsangabi R, Hajmomenian M, Santi M, Vossough A
Department of Radiology, Children's Hospital of Philadelphia, Perelman School of Medicine of the University of Pennsylvania, 324S 34th Street - Wood 2115, Philadelphia, PA, 19104, USA,
Neuroradiology. 2015 May;57(5):527-33. doi: 10.1007/s00234-015-1497-5. Epub 2015 Feb 10.
Pilomyxoid astrocytoma (PMA) is a relatively new tumor entity which has been added to the 2007 WHO Classification of tumors of the central nervous system. The goal of this study is to utilize arterial spin labeling (ASL) perfusion imaging to differentiate PMA from pilocytic astrocytoma (PA).
Pulsed ASL and conventional MRI sequences of patients with PMA and PA in the past 5 years were retrospectively evaluated. Patients with history of radiation or treatment with anti-angiogenic drugs were excluded.
A total of 24 patients (9 PMA, 15 PA) were included. There were statistically significant differences between PMA and PA in mean tumor/gray matter (GM) cerebral blood flow (CBF) ratios (1.3 vs 0.4, p < 0.001) and maximum tumor/GM CBF ratio (2.3 vs 1, p < 0.001). Area under the receiver operating characteristic (ROC) curves for differentiation of PMA from PA was 0.91 using mean tumor CBF, 0.95 using mean tumor/GM CBF ratios, and 0.89 using maximum tumor/GM CBF. Using a threshold value of 0.91, the mean tumor/GM CBF ratio was able to diagnose PMA with 77 % sensitivity, 100 % specificity, and a threshold value of 0.7, provided 88 % sensitivity and 86 % specificity. There was no statistically significant difference between the two tumors in enhancement pattern (p = 0.33), internal architecture (p = 0.15), or apparent diffusion coefficient (ADC) values (p = 0.07).
ASL imaging has high accuracy in differentiating PMA from PA. The result of this study may have important applications in prognostication and treatment planning especially in patients with less accessible tumors such as hypothalamic-chiasmatic gliomas.
毛黏液样星形细胞瘤（PMA）是一种相对较新的肿瘤类型，已被纳入2007年世界卫生组织中枢神经系统肿瘤分类中。本研究的目的是利用动脉自旋标记（ASL）灌注成像来鉴别PMA与毛细胞型星形细胞瘤（PA）。
回顾性评估过去5年中PMA和PA患者的脉冲ASL及传统MRI序列。排除有放疗史或接受过抗血管生成药物治疗的患者。
共纳入24例患者（9例PMA，15例PA）。PMA和PA在平均肿瘤/灰质（GM）脑血流量（CBF）比值（1.3对0.4，p<0.001）和最大肿瘤/GM CBF比值（2.3对1，p<0.001）方面存在统计学显著差异。用于区分PMA与PA的受试者操作特征（ROC）曲线下面积，使用平均肿瘤CBF为0.91，使用平均肿瘤/GM CBF比值为0.95，使用最大肿瘤/GM CBF为0.89。使用0.91的阈值，平均肿瘤/GM CBF比值诊断PMA的灵敏度为77%，特异性为100%；使用0.7的阈值，灵敏度为88%，特异性为86%。两种肿瘤在强化模式（p=0.33）、内部结构（p=0.15）或表观扩散系数（ADC）值（p=0.07）方面无统计学显著差异。
ASL成像在鉴别PMA与PA方面具有较高准确性。本研究结果在预后评估和治疗规划中可能具有重要应用，尤其是对于下丘脑-视交叉神经胶质瘤等难以触及的肿瘤患者。
