环状强化内的扩散受限对脑脓肿而言并非具有特征性。
Restricted diffusion within ring enhancement is not pathognomonic for brain abscess.
作者信息
Hartmann M, Jansen O, Heiland S, Sommer C, Münkel K, Sartor K
机构信息
Department of Neuroradiology, University of Heidelberg Medical School, Heidelberg, Germany.
出版信息
AJNR Am J Neuroradiol. 2001 Oct;22(9):1738-42.
BACKGROUND AND PURPOSE
Recent experience suggests that diffusion-weighted MR imaging may be decisive in the differential diagnosis of ring-enhancing cerebral lesions. Whether restricted diffusion within a ring-enhancing cerebral mass lesion is pathognomonic for abscess was studied.
METHODS
Seventeen patients with ring-enhancing cerebral lesions (three abscesses, six glioblastomas, eight 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. Lesions with signs of intralesional hemorrhage on unenhanced T1-weighted images were excluded.
RESULTS
The central portion of all six glioblastomas and seven of eight metastases showed unrestricted diffusion, whereas two of three abscesses showed restricted diffusion (low ADC values) in their cavity. However, restricted diffusion also was found in one metastasis, and one abscess within a postoperative cavity showed unrestricted diffusion within a larger nondependent portion.
CONCLUSION
In patients with ring-enhancing cerebral mass lesions, restricted diffusion might be characteristic but is not pathognomonic for abscess, as low ADC values also may be found in brain metastases.
背景与目的
近期经验表明，磁共振扩散加权成像在环形强化脑病变的鉴别诊断中可能起决定性作用。本研究旨在探讨环形强化脑实质病变内的扩散受限是否为脓肿的特征性表现。
方法
对17例在常规对比增强T1加权像上表现为环形强化脑病变（3例脓肿、6例胶质母细胞瘤、8例转移瘤）的患者进行了回波平面扩散加权磁共振成像检查。计算所有病变的表观扩散系数（ADC）图及ADC值。排除在未增强T1加权像上有瘤内出血征象的病变。
结果
所有6例胶质母细胞瘤及8例转移瘤中的7例，其中心部分表现为扩散不受限，而3例脓肿中的2例在其腔内表现为扩散受限（ADC值低）。然而，1例转移瘤也发现有扩散受限，1例术后腔内脓肿在较大的非下垂部分表现为扩散不受限。
结论
在环形强化脑实质病变患者中，扩散受限可能是脓肿的特征，但并非脓肿所特有，因为在脑转移瘤中也可能出现低ADC值。
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