Department of Medical Imaging, Buddhist Tzu Chi General Hospital, Taipei, and School of Medicine, Tzu Chi University, Hualien, Taiwan.
J Magn Reson Imaging. 2009 Nov;30(5):1078-84. doi: 10.1002/jmri.21960.
To investigate the feasibility of a vessel size imaging (VSI) technique with separate contrast agent injections for evaluation of the vessel caliber in normal tissues and in brain tumors.
Computer simulation was first performed to assess the potential errors in the estimation of vessel caliber that could result from time shifts between the dual contrast agent injections. Eight patients (four female, four male, 37-77 years old) with brain tumors (three high-grade gliomas, two low-grade gliomas, and three meningiomas) were recruited for clinical study. Dynamic susceptibility contrast magnetic resonance imaging (MRI) using gradient echo (GE) and spin echo (SE) echo-planar imaging sequences were performed separately with a 10-minute interval on a 3.0T scanner. Vessel caliber maps were calculated and analyzed in regions of interest at cortical gray matter (GM), thalamus, white matter (WM), and tumors.
From the computer simulation, the error of vessel caliber measurement was less than 8% when the difference between the time-to-peak of the GE and the SE studies was 1.5 seconds, and reduced to within 5% when the difference was 1 second. From the patient datasets of a 64 x 64 matrix, the estimated vessel calibers were 37.4 +/- 12.9 microm for cortical gray matter, 20.7 +/- 8.8 microm for thalamus, and 15.0 +/- 5.1 microm for white matter, comparable to results in the literature. Two patients had a VSI with 128 x 128 matrix and showed similar results in vessel calibers of normal tissues. All the tumors had larger mean vessel diameter than normal-appearing tissues. The difference in vascular size between normal tissue and tumor was demonstrated clearly in both the VSIs of regular and high spatial resolution.
This study suggests that VSI with a dual injection method is a feasible technique for estimating microvascular calibers of normal tissues and brain tumors in clinical scanners.
探讨分别注射对比剂的血管大小成像（VSI）技术评估正常组织和脑肿瘤血管口径的可行性。
首先通过计算机模拟评估双对比剂注射时间差异可能导致的血管口径估计中的潜在误差。招募 8 例脑肿瘤患者（4 例女性，4 例男性，37-77 岁）进行临床研究。在 3.0T 扫描仪上分别使用梯度回波（GE）和自旋回波（SE）EPI 序列进行动态磁敏感对比磁共振成像（MRI）。在皮质灰质（GM）、丘脑、白质（WM）和肿瘤的感兴趣区计算并分析血管口径图。
从计算机模拟结果来看，当 GE 和 SE 研究的时间至峰值差异为 1.5 秒时，血管口径测量误差小于 8%；当差异为 1 秒时，误差降低至 5%以内。从 64 x 64 矩阵的患者数据集来看，皮质灰质的估计血管口径为 37.4 +/- 12.9 微米，丘脑为 20.7 +/- 8.8 微米，白质为 15.0 +/- 5.1 微米，与文献结果相当。2 例患者进行了 128 x 128 矩阵的 VSI，显示正常组织血管口径相似。所有肿瘤的平均血管直径均大于正常组织。在常规和高空间分辨率的 VSI 中，均清晰显示了正常组织和肿瘤之间血管大小的差异。
本研究表明，双注射方法的 VSI 是一种在临床扫描仪中评估正常组织和脑肿瘤微血管口径的可行技术。
