目的 探讨颅内毛细胞型星形细胞瘤(PA)的影像学特征及与临床病理的关系.资料与方法 对本院经病理证实的70例PA的CT和MRI表现进行回顾性分析,并与临床病理对照研究.结果 70例PA分别位于小脑28例、中线结构23例、大脑半球19例.11例在CT上可见钙化,12.8%在CT/MRI上可见出血性改变;而病理上14例可见钙化,31.4%可见陈旧性出血.在影像上37.1%的PA呈囊实性伴有壁结节强化而无囊壁强化,22.9%有囊壁及壁结节强化,12.9%为实性伴坏死并不规则不均匀强化,27.1%为实性伴有微囊或无囊性结构并明显均匀强化.扩散加权成像(DWI)上PA的实性成分呈等或低信号,ADC值平均1.63×10~(-3)mm~2/s.在MR灌注上肿瘤实性部分呈高灌注,肿瘤的肌酸(Cr)和N.乙酰天门冬氨酸(NAA)降低,并可见乳酸峰.结论 PA的影像学表现具有一定特征,小脑和大脑半球的PA以囊实性为主、中线结构PA以实性为主,PA内钙化和出血并不少见.MRI灌注、DWI和磁共振波谱(MRS)在PA的诊断和鉴别中具有一定的价值.“,”Objective To evaluate imaging features of brain pilocytic astrocytomas (PA) and correlation with clinical pathological findings. Materials and Methods The imaging features of 70 PAs include CT,conventional MRI, MR peffusion, DWI and ADC value were analyzed retrospectively,and the correlation of imaging features with clinical pathological findings were evaluated. Results Seventy PAs located at cerebellum 28, midline structure 23 and 19 eases in cerebral hemispheres. Calcifications were seen in 11 cases on CT and 14 eases on clinical-pathology, 12.8% eases with bleedings were detected on CT/MRI and 31.4% in clinical-pathology. On CT/MRI imaging,37.1% eases showed as cystlike mass with an intensely enhancing mural nodule but nonenhancing cyst wall, 22.9% with intensely enhancing mural nodule and cyst wall, 12.9% showed as necrotic mass with a central nonenhancing zone,and 27.1% were predominantly solid mass with minimal to no cystlike component and enhance intensely. On DWI, the solid component of tumor is isointense or hypointense, the average ADC value was 1.63 × 10~(-3) mm~2/s. On MRI perfnsion,the solid part of tumors were showed high rCBV compared with norreal parenchyma. Conclusion PA has some characteristic imaging features,Most of PA occurred in cerebellum and cerebralhemispheres were cystlike mass with an enhancing mural nodule,and with or with not cyst wall enhancement. Most of the lesions occurred in or near the midline were solid mass. MRI perfusion, DWI and MRS were useful technique in the PA diagnosis and differentiate with other tumors.