Diffusion-weighted MR Imaging Of Normal Kidneys And Focal Renal Lesions

Part Ⅰ Comparison of breathhold, respiratory-triggered, and free-breathingdiffusion-weighted MR Imaging of normal kidneys and focal renal lesions.Purpose: To compare apparent diffusion coefficient (ADC) and image quality onnormal kidneys and focal renal lesions among respiratory-triggered DWI(RT-DWI),free-breathing-DWI(FB-DWI) and breathhold-DWI(BH-DWI). Materials andMethods: Thirty healthy volunteers and forty-two patients with focal renal lesionsunderwent three series of DWI including BH-DWI, RT-DWI and FB-DWI scans withb values of0and800sec/mm2.Signal-to-ratio(SNR) of the kidney, and contrast tonoise ratio(CNR) of the lesions were measured in each DWI sequence and statisticallycompared using analysis of variance (AVOVA). So did ADCs of normal kidneys andrenal lesions. ADC values of kidneys between repeated measurement were comparedby using t-test. Consistency of the ADC measurement among three sequences and thereliability of ADC measurement between repeated measurement were determined byusing ICCs. Results: The SNR and CNR were significantly higher on non-breathholdDWI than breathold DWI (P<0.05). ADC values of the normal renal parenchyma andfocal lesions also showed no significant differences among the three sequences(P>0.05).Good consistency of ADC measurement was deserved on three sequences involunteers’ kidneys and renal focal lesions (ICCvolunteer=0.866, ICCCCRCC=0.913,ICCAML=0.870, ICCcyst=0.876) except for UC (ICCUC=0.561). There was nostatistical difference of ADC values in each sequence between repeated measurements,and good reproducibility of ADC measurement between repeated measurements(ICCRT=0.766, ICCFB=0.876, ICCBH=0.810) Conclusion: Imaging patterns of DWIexerted no influence on ADC measurement. Non-breathhold DWI might be moreappropriate for kidneys due to better imaging quality and without compromised ADC values. Part Ⅱ Comparison of1.5T and3.0T diffusion-weighted MR imaging in normalkidneys and focal renal lesions.Purpose: To compare diffusion-weighted MR imaging of kidneys between1.5T and3.0T in healthy volunteers and focal renal lesions in terms of SNR, CNR and ADCvalues and to evaluate consistency of ADC measurement on two field strengthMaterials and Methods: Thirty healthy volunteers and twenty-five patients withfocal renal lesions underwent consecutive scans on1.5T and3.0T, at b-values of0and800sec/mm2. SNR, CNR of the lesions, ADCs of renal parenchyma and renal lesionswere measured in each field strength and statistically compared using the paired-t-test.Consistency of ADC measurement on two field strength was assessed by using ICC.Results: The SNR, CNR of the renal parenchyma on3.0T was significantly higherthan1.5T (P<0.01). ADC values of the normal renal parenchyma and focal lesionsshowed no significant differences between1.5T and3.0T(P>0.05). There were goodto moderate consistency of ADC measurement on the two field strength(ICCvolunteer=0.826, ICCCCRCC=0.972, ICCAML=0.818, ICCUC=0.754, ICCcyst=0.696).Conclusion: Field strength had no effect on ADC measurement between1.5T and...