A free-breathing non-contrast-enhanced pulmonary magnetic resonance angiography at 3 Tesla  

作　　者：YANG Jian WANG Wei WANG Ya-rong NIU Gang JIN Chen-wang WU Ed Xuekui 

机构地区：[1]Medical Imaging Center, First Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China [2]Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China [3]Department of Diagnostic Radiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China [4]School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China

出　　处：《Chinese Medical Journal》2009年第18期2111-2116,共6页中华医学杂志（英文版）

基　　金：This work was supported in part by grants from the National Natural Science Foundation of China （No.30200066）, Ph.D. Programs Foundation of the Ministry of Education of China （No. 2004069805） and Hong Kong Research Grant Council （No. GRF7794/07M）.

摘　　要：Background The breathhold contrast-enhanced three-dimensional magnetic resonance angiography （MRA） using Tl-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla. Methods The time-of-flight protocol was based on a two-dimensional Tl-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects. Results Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of -300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20°-30°. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel. Conclusions The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.Background The breathhold contrast-enhanced three-dimensional magnetic resonance angiography （MRA） using Tl-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla. Methods The time-of-flight protocol was based on a two-dimensional Tl-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects. Results Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of -300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20°-30°. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel. Conclusions The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.

关 键 词：magnetic resonance angiography PULMONARY blood vessels 

分 类 号：R686[医药卫生—骨科学]