Rollin N, Guyotat J, Streichenberger N, Honnorat J, Tran Minh V-A, Cotton F
Department of Radiology, Lyon University School of Medicine, France.
Neuroradiology. 2006 Mar;48(3):150-9. doi: 10.1007/s00234-005-0030-7. Epub 2006 Feb 10.
Advanced magnetic resonance (MR) imaging techniques provide physiologic information that complements the anatomic information available from conventional MR imaging. We evaluated the roles of diffusion and perfusion imaging for the assessment of grade and type of histologically proven intraaxial brain tumors. A total of 28 patients with intraaxial brain tumors underwent conventional MR imaging (T2- and T1-weighted sequences after gadobenate dimeglumine injection), diffusion imaging and T2*-weighted echo-planar perfusion imaging. Examinations were performed on 19 patients during initial diagnosis and on nine patients during follow-up therapy. Determinations of relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) were performed in the solid parts of each tumor, peritumoral region and contralateral white matter. For gliomas, rCBV values were greater in high-grade than in low-grade tumors (3.87+/-1.94 versus 1.30+/-0.42) at the time of initial diagnosis. rCBV values were increased in all recurrent tumors, except in one patient who presented with a combination of recurrent glioblastoma and massive radionecrosis on histology. Low-grade gliomas had low rCBV even in the presence of contrast medium enhancement. Differentiation between high- and low-grade gliomas was not possible using diffusion-weighted images and ADC values alone. In the peritumoral areas of untreated high-grade gliomas and metastases, the mean rCBV values were higher for high-grade gliomas (1.7+/-0.37) than for metastases (0.54+/-0.18) while the mean ADC values were higher for metastases. The rCBV values of four lymphomas were low and the signal intensity-time curves revealed a significant increase in signal intensity after the first pass of gadobenate dimeglumine. Diffusion and perfusion imaging, even with relatively short imaging and data processing times, provide important information for lesion characterization.
先进的磁共振（MR）成像技术可提供生理信息，对传统MR成像所提供的解剖信息起到补充作用。我们评估了弥散成像和灌注成像在评估经组织学证实的脑内肿瘤的分级和类型方面的作用。共有28例脑内肿瘤患者接受了传统MR成像（钆贝葡胺注射后的T2加权和T1加权序列）、弥散成像和T2*加权回波平面灌注成像。19例患者在初始诊断时进行了检查，9例患者在后续治疗期间进行了检查。在每个肿瘤的实性部分、瘤周区域和对侧白质中测定相对脑血容量（rCBV）和表观扩散系数（ADC）。对于胶质瘤，初始诊断时高级别肿瘤的rCBV值高于低级别肿瘤（3.87±1.94对1.30±0.42）。除1例组织学表现为复发性胶质母细胞瘤合并大量放射性坏死的患者外，所有复发性肿瘤的rCBV值均升高。低级别胶质瘤即使在有对比剂增强的情况下rCBV值也较低。仅使用弥散加权图像和ADC值无法区分高级别和低级别胶质瘤。在未经治疗的高级别胶质瘤和转移瘤的瘤周区域，高级别胶质瘤的平均rCBV值（1.7±0.37）高于转移瘤（0.54±0.18），而转移瘤的平均ADC值更高。4例淋巴瘤的rCBV值较低，信号强度-时间曲线显示钆贝葡胺首次通过后信号强度显著增加。弥散成像和灌注成像，即使成像和数据处理时间相对较短，也能为病变特征提供重要信息。
