脑结核瘤的磁共振成像

目的 分析颅内结核的磁共振表现。材料与方法 对12例脑结核瘤MRI表现及Gd-DTPA强化的特点进行回顾性分析。T1WI和T2WI信号强度与正常脑灰质进行比较。结果 3例粟粒样脑结核瘤呈脑内散在的多发等或略长T1、长T2信号，结节样均匀强化或伴有少量小环状强化。9例31个成熟结核瘤由环壁和坏死的核心两部分组成，环壁呈等T1、短T2信号（5个病灶）和等或略长T1、等或略长T2信号（26个病灶），单环或花簇状环状强化；14个未成熟结核瘤呈结节样等或略长T1、长T2信号，均匀强化。成熟结核瘤的核心部分因组织病理学的差异可有多种信号。颅内结核瘤以1个主灶伴多个小灶为其主要表现形式（77.8%，7/9）。结论 T1WI呈等或略高信号，T2WI呈轻度不均匀等或略低信号，不均匀单环或花簇环状强化是结核的主要MRI表现。而病灶的多发性符合脑结核系血行播散所致的发病机理，对确立诊断有非常重要的价值。

MRI of Intracranial Tuberculoma

Objective To study MRI features of intracranial tuberculoma.Materials and Methods MRI findings, including signal intensity and Gd DTPA enhancement pattern, of intracranial tuberculoma in 12 patients were retrospectively analyzed. Signal intensities on T 1WI and T 2WI were compared with normal gray matter.Results In 3 disseminated tuberculoma cases, the lesions showed multiple iso or slightly hypo intensity signal on T 1WI and hyper intensity signal on T 2WI, with homogenous nodular, and somewhat annular, enhancement. In 9 patients, 31 matured tuberculomas were composed of a necrotic core and a surrounding capsule. The capsule showed iso intensity or slight hyper intensity signal on T 1WI, while iso intensity or slight hyper intensity (n=26) and hyper intensity (n=5) signal on T 2WI. On post contrast T 1WI, single or multiple lesions with clustered or ring like enhancement were seen. Fourteen immature tuberculomas showed iso intensity on T 1WI and slight hyper intensity on T 2WI, while homogenous enhancement on post contrast T 1WI. The commonest finding of intracranial tuberculoma was a large main lesion surrounded by multiple daughter lesions (77.8%).Conclusion On MRI, the intracranial tuberculomas are characterized by iso or slightly hyper intensity on T 1WI, slight heterogenous iso-intensity or hypo intensity on T 2WI, and conglomerate ring like enhancement of the lesion. The multiplicity of the lesion is consistent with the hematogeneous spread of tuberculous infection, which plays an important role in establishing the diagnosis.