Impact of Field Strength and Respiratory Motion Control on Diffusion-Weighted MR Imaging of the Liver

作     者：Johanna Berg Sven Mansson Jonas Svensson Olle Ekberg Markus F.Müller 

作者机构：Skane University HospitalDepartment of Clinical SciencesLund UniversityMalmoSweden Medical RadiologyLund UniversityMalmoSweden Medical Radiation PhysicsLund UniversityMalmoSweden 

出 版 物：《Open Journal of Medical Imaging》 (医学影像期刊（英文）)

年 卷 期：2013年第3卷第1期

页      面：31-39页

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

主　　题：Magnetic Resonance Imaging Diffusion Echo-Planar Imaging 3 T Liver Respiratory Motion 

摘      要：Purpose: To evaluate the impact of field strength and respiratory motion control on diffusion-weighted MR imaging (DWI) of the liver at 1.5 and 3 T. Material and Methods: Three DWI sequences using seven b-values from 20 - 400 s/mm2 were designed with identical parameters but with different handling of respiratory motion [respiratory triggered (RT), free breathing (FB), breath hold (BH)] on 3 T and 1.5 T. Thirteen volunteers were examined at a 3 T and six of them also at a 1.5 T magnet. DW images were analyzed quantitatively and qualitatively. Regions of interest were placed in cranial, middle and caudal parts of the right liver lobe (RLL) and ADC and SNR were calculated. Results: ADC in RLL tended to be lower at 3 T MRI. Least inter-subject ADC variability was found with RT in the middle RLL at 3 T. Highest ADCs were found caudally in the RLL. Significant differences in ADC between middle and caudal RLL were calculated in FB and RT at 3 T and FB and BH at 1.5 T, respectively. No significant difference in SNR was found between 3 T and 1.5 T. There were significantly more artifacts in the left liver lobe (LLL) compared to the RLL in all sequences and in the LLL at 3 T compared to 1.5 T. Conclusion: Our study suggests that longitudinal hepatic ADC measurements should be performed using equivalent field strength, b-values, and acquisition technique, given influence of these factors on ADC measurements.