三维颅脑容积磁共振成像技术在颅脑磁共振增强检查的价值

目的 评价1.5 T HDx磁共振成像(MRI)系统新技术颅脑容积磁共振成像(BRAVO)在颅脑磁共振增强检查中的价值.方法 对31例颅脑肿瘤患者或町疑颅脑转移的患者行常规磁共振增强检查和BRAVO序列检查.分别计算自旋回波(SE)序列及BRAVO序列的病灶显示数量,采用χ2检验方法对结果进行比较;对比图像质量,分别测量两序列灰质、白质及背景噪声信号值,运用公式计算信噪比(SNR)、对比噪声比(CNR)以及灰白质对比度.结果 在31例颅脑MRI检查中,SE序列共显示病灶121个,BRAVO序列共显示病灶124个,两者比较其差异无统计学意义(P＞0.05);BRAVO与SE序列的白质信噪比(17.828 7±2.753 1和27.226 1±5.571 2),灰质信噪比(12.964 2±1.796 3和23.174 1±4.513 3)差异均有统计学意义(P＜0.05),sE序列的灰质、白质信噪比均高于BRAVO序列.BRAVO与SE序列的灰白质对比噪声比(CNRWM/GM)(4.865 2±1.1370和4.051 6±1.3900),灰白质对比度(635.211 3±136.385 0和93.494 2±25.1724),差异均有统计学意义(P＜0.05),BRAVO序列均高于SE序列.结论 BRAVO序列实现了磁共振颅脑增强容积快速扫描的可能,扫描一个序列能重建出多平面图像,同时以高空间分辨率、较少的血管搏动伪影以及较高的灰白纸对比度为颅脑磁共振扫描提供更广阔的前景,在颅脑磁共振增强检查中起到重要的补充作用.

Application of three-dimensional BRAVO techniques in enhanced MRI of the brain

Objective To evaluate the brain volume imaging (BRAVO) sequence built in 1.5T HDx magnetic resonance imaging (MRI) system for enhanced scanning of the brain.Methods Thirty-one patients with primary tumor or suspected metastatic lesions of the brain underwent both MRI with routine contrast-enhanced spin echo(SE) sequence and BRAVO sequence.Number of lesions revealed under both SE sequence and BRAVO sequence was calculated and compared by Chi-square test.Then the values of grey and white matters, and value of noise on the background signal under both sequences were measured.According to these values, signal to noise ratio (SNR) about gray matter and white matter, contrast to noise ratio between white matter and gray matter (CNRwmkm) were computed.In addition, white/gray matter contrast was measured and calculated, and the results were compared and statistically analyzed with J-test.Results There were 121 lesions revealed by SE sequence vs 124 by BRAVO sequence in the 31 patients, with no statistically significant difference in number of lesions noted by the two sequences (P>0.05).Significant differences were noted in both white matter SNR BRAVO:(17.828 7±2.753 1); SE: (27.226 1 ±5.571 2)] and gray matter SNR BRAVO: (12.964 2±1.796 3); SE:(23.174 1 ±4.513 3); P＜0.05 ].SNRwm/cm of SE sequence was higher than that of BR A VO sequence.CNRwm/cm on SE sequence was lower than that on BRAVO sequence BRAVO: (4.865 2±1.137 0); SE: (4.051 6±1.390 0),P＜0.05], as was gray/white matter contrast on SE sequence than that on BRAVO sequence BRAVO.(635.211 3±○136.385 0); SE: (93.494 2±25.172 4); P＜0.05].Conclusions BRAVO sequence may enable quicker brain volumetric scan in enhanced MRI.With BRAVO, multi-plane images can be reconstructed by scanning one sequence.In addition, the higher spatial resolution, less vascular motion artifacts and higher gray/white matter contrast with BRAVO technique mean a wider prospect for brain MRI, where it can be an important supplementary in enhanced MR imaging of the brain.