扩散加权成像对颅内环形强化病灶的鉴别诊断价值

Role of DWI in the differential diagnosis of ring-enhanced intracranial cystic lesions

目的探讨磁共振扩散加权成像(DW I)对颅内环形强化病灶的鉴别诊断价值。方法对46例环形强化病灶(脑脓肿7例、胶质瘤23例、转移瘤16例)行常规MR I、DW I及增强扫描。自动获得表观弥散系数(ADC)图并进行ADC值测量。结果所有23例胶质瘤中的20例、16例转移瘤中的13例瘤腔显示弥散不受限(高ADC值),7例脑脓肿中的5例脓腔显示弥散受限(低ADC值)。胶质瘤中有3例显示部分弥散受限;转移瘤中有1例弥散受限,两例多发转移瘤,部分弥散受限,部分弥散不受限。脑脓肿中有2例部分弥散不受限。结论在颅内环形强化病灶中,DW I上绝大多数脓肿弥散受限,表现为高信号,但部分胶质瘤和转移瘤也可为高信号。

Objective： To evaluate the role of DWI in the differential diagnosis of ring-enhanced intracranial cysticlesions. Methods： Forty- six patients with ring-enhancing cerebral lesions （7 abscesses, 23 glioblastomas, 16 metastases） on conventional contrast-enhanced T1-weighted images were examined with echo-planar diffusion-weighted MR imaging. Apparent diffusion coefficient （ADC） maps and the ADCs were calculated for all lesions. Results： The central portion of all 20 of 23 glioblastomas and 13 of 16 metastases showed unrestricted diffusion, whereas 5 of 7 abscesses showed restricted diffusion in their cavity. However, restricted diffusion was also found in one metastasis and 3 glioblastomas. Unrestricted diffusion was found in 2 abscesses. Conclusion： In patients with ring-enhancing cerebral mass lesions, restricted diffusion might be characteristic but not pathognomonic for abscess, as low ADC values may also be found in brain metastases and glioblastomas.