3特斯拉磁共振成像中脑肿瘤强化：使用快速自旋回波（TSE）和梯度回波（GRE）技术的信噪比（SNR）和对比噪声比（CNR）增益比较

Brain tumor enhancement in MR imaging at 3 Tesla: comparison of SNR and CNR gain using TSE and GRE techniques.

作者信息

Wintersperger Bernd J, Runge Val M, Biswas Jonmenjoy, Reiser Maximilian F, Schoenberg Stefan O

机构信息

Department of Clinical Radiology, University Hospitals Grosshadern, Ludwig-Maximilians-University, Munich, Germany.

出版信息

Invest Radiol. 2007 Aug;42(8):558-63. doi: 10.1097/RLI.0b013e31803e8b3f.

DOI:10.1097/RLI.0b013e31803e8b3f

PMID:17620938

Abstract

PURPOSE

The purpose of this study was to compare brain and tumor signal characteristics of T1-weighted turbo spin-echo (TSE) and gradient recalled echo (GRE) sequence techniques at 3 T compared to TSE at 1.5 T, focusing on the detection of contrast enhancement, in a standardized animal model of a brain glioma.

MATERIALS AND METHODS

Twelve rats with implanted brain gliomas were evaluated at 1.5 and 3 T using matched hardware configurations. At 1.5 T, scanning was performed using a TSE sequence optimized for field strength (480/15 milliseconds; 125 Hz/Px) with postcontrast scans acquired at multiple time points after gadoteridol injection (0.1 mmol/kg). At 3 T, scanning was performed using the 1.5 T equivalent TSE as well as with TSE and GRE techniques optimized for 3 T. Signal-to-noise ratio (SNR) of brain and tumor and tumor contrast-to-noise ratio (CNR) were evaluated for all techniques at both field strengths.

RESULTS

Postcontrast tumor SNR (63.7 +/- 10.8 vs. 29.5 +/- 4.3; P < 0.0001) and brain SNR (35.8 +/- 1.5 vs. 19.1 +/- 0.7; P < 0.0001) showed significant increase at 3 T using matched TSE. Comparing TSE optimized to each field strength (for optimized gray-white contrast), tumor and brain SNR still showed a significant increase at 3 T of 73% and 56%, respectively (both P < 0.0001). Comparing TSE at 1.5 T and GRE at 3 T, tumor SNR increased by 105%, whereas brain SNR increased by 141% (both P < 0.0001). Tumor CNR with matched TSE increased by 168% (P < 0.0001), with optimized TSE by 111% (P < 0.0001), and with GRE at 3 T versus TSE at 1.5 T by 36% (P < 0.001). With additional adjustments for echo time the gain in tumor CNR for 2D GRE may again reach 60%.

CONCLUSIONS

With TSE at 3 T, the SNR gain comes close to the theoretically expected doubling with an even higher tumor CNR increase. In a clinical like setting at 3 T, where a T1w GRE sequence is used, tumor CNR gain is limited. Contrast dose should therefore not be decreased at 3 T.

摘要

目的

本研究旨在比较在3T场强下，T1加权快速自旋回波（TSE）和梯度回波（GRE）序列技术与1.5T场强下TSE的脑和肿瘤信号特征，重点关注在标准化脑胶质瘤动物模型中对比增强的检测。

材料与方法

使用匹配的硬件配置，对12只植入脑胶质瘤的大鼠在1.5T和3T场强下进行评估。在1.5T场强下，使用针对场强优化的TSE序列（480/15毫秒；125Hz/像素）进行扫描，并在注射钆特醇（0.1mmol/kg）后的多个时间点进行增强扫描。在3T场强下，使用与1.5T等效的TSE以及针对3T场强优化的TSE和GRE技术进行扫描。评估两种场强下所有技术的脑和肿瘤信噪比（SNR）以及肿瘤对比噪声比（CNR）。

结果

使用匹配的TSE序列时，增强后肿瘤SNR（63.7±10.8对29.5±4.3；P<0.0001）和脑SNR（35.8±1.5对19.1±0.7；P<0.0001）在3T场强下显著增加。比较针对每个场强优化的TSE（为优化灰白对比度），肿瘤和脑SNR在3T场强下仍分别显著增加73%和56%（均P<0.0001）。比较1.5T场强下的TSE和3T场强下的GRE，肿瘤SNR增加了105%，而脑SNR增加了141%（均P<0.0001）。匹配的TSE序列下肿瘤CNR增加了168%（P<0.0001），优化的TSE序列下增加了111%（P<0.0001），3T场强下的GRE与1.5T场强下的TSE相比增加了36%（P<0.001）。对回波时间进行额外调整后，二维GRE的肿瘤CNR增益可能再次达到60%。