The Clinical Study Of Functional Magnetic Resonance Imaging In Chronic Kidney Disease

Partâ… The clinical application of diffusion-weighted imaging with navigator-triggered prospective acquisition correction in kidney:initial experienceObjective:To evaluate the Reproducibility of renal apparent diffusion coefficient (ADC) measured by diffusion-weighted imaging with navigator-triggered prospective acquisition correction(PACE-DWI),and to compare the signal to noise ratio(SNR) and contrast to noise ratio(CNR) of DWI images with conventional DWI with breathholding.Materials and methods:Fifteen healthy volunteers accepted a repetitive DWI examination within a interval of 5 to 42 days.Two DWI sequences were performed on every subject at b values of 100,300,500,800 and 1000 s/mm²,including a single-shot spin-echo echo-planar sequence within a single breath-hold and a spin-echo echo-planar sequence with PACE.The repetitive measured ADCs by PACE-DWI were compared using the matched-pairs T test,the Bland-Altman plot and Concordance correlation coefficient.The differences of SNR and CNR between DWI with breathholding and PACE-DWI was analyzed using the Mann-Whitney U test.The Kruskal-Wallis H test was used to compare the difference of SNR and CNR among DWI with different b values.The influence of different DWI sequences on ADC measurement was analyzed by the Wilcoxon matched-pairs signed-ranks test. The Friedman test was used to analyze the influence of b value on ADC measurement.Results:There was no significant statistical difference between the ADCs of renal parenchyma repetitive measured by PACE-DWI(P＞0.05).The absolute differences of repetitive measured ADCs of renal parenchyma and the limits of agreement by PACE-DWI were -4.4×10^-5 mm²/s to -6.3×10^-5 mm²/s and±28.1×10^-5 to±36.4×10^-5 mm²/s except when b=100 s/mm².In addition,there was a high concordance between repetitive measured ADCs of renal parenchyma by PACE-DWI(ρ_c=0.892,P=0.000). Higher SNR and CNR were obtained by PACE-DWI than those by conventional DWI group at the same b Value,and the differences were statistically significant(P＜0.05). The SNR and CNR of DWI images decreased as the b Value increased in both conventional DWI and PACE-DWI,and there was significant statistical difference among the same group with five b Values(P＜0.01).However,higher ADCs were obtained by PACE-DWI than those by conventional DWI at the same b Value,and the differences were statistically significant except the ADCs of right renal parenchyma with b value of 100 s/mm²(P＜0.05).The measured ADCs of renal parenchyma decreased as the b Value increased in both conventional DWI and PACE-DWI,and there was significant statistical differences among the same group with five b Values (P＜0.01).Conclusion:PACE-DWI has a good reproducibility in the measurement of ADCs of renal parenchyma and will benefit clinical researchs due to its higher SNR and CNR than conventional DWI with breathholding.However,there is still some differences between ADCs measured by PACE-DWI and conventional DWI.Partâ…¡Clinical study of diffusion-weighted imaging in renal function assessment of chronic kidney diseaseObjective:To investigate the value of DWI in the evaluation of clinical staging and split renal function of(chronic kidney disease) CKD,and to discuss whether or not DWI with navigator-triggered prospective acquisition correction(PACE-DWI) is superior to conventional DWI with breathholding.In addition,the influence of renal volume on renal function is discussed.Materials and Methods:Eighty-three CKD patients and 12 healthy volunteers underwent DWI examination using both a single-shot spin-echo echo-planar sequence within a single breath-hold and a spin-echo echo-planar sequence with PACE at b values of 300 and 800 s/mm².Among them,54 patients received radionuclide renography examination,and the glomerular filtration rate(GFR) is calculated based on the Gates Method.One-way analysis of variance(ANOVA) was used to compare the average apparent diffusion coefficient(ADC) of both kidney among different clinical stages,the ADCs of split kidney,the volume of split kidney and the split volume-corrected renal ADCs among the three groups with different split renal function.The partial correlation test with the control of age and receiver operationg characteristics analysis(ROC) were used to assess the performance of split renal ADCs,split renal volume and split volume-corrected renal ADCs in the evaluation of split renal function and predicting the reduction or mild reduction of split renal function.Results:The average ADCs of both kidneys decreased as the clinical stage of CKD progressed.There was a statistically significant difference among the five clinical stages(P＜0.01),and between stage one to two and stage three to five at b value of 800 s/mm²(P＜0.05).There was a weak positive correlation between the split ADCs and split GFR.The best correlation was observed for PACE-DWI with b value 800 s/mm²(r=0.471,P=0.000).The split renal ADCs measured by PACE-DWI were significant different among these three groups with different GFR(P＜0.01) and was also a significant predictor of mild split renal function reduction for PACE-DWI with b value 800s/mm²,with an area under the curve of 0.780(P=0.000).There was a weak positive correlation between split renal volume and renal GFR(r=0.470, P=0.000).However,there was a moderate positive correlation between the split volume-corrected renal ADC and renal GFR(r=0.521 to 0.550,P=0.000).The split volume-corrected renal ADCs were significant different among these three groups with different GFR(P＜0.01) and the diagnosis potency predicting mild split renal function reduction was improved too(AUC=0.824 to 0.841,P=0.000).Conclusion:Renal ADC measured by DWI can be used in the assessment of clinical stage and split renal function of CKD.PACE-DWI with b value 800s/mm² is the best in assessing split renal function,and has potential value in predicting mild reduction of split renal function.In addition,renal volume can not be ignored in the evaluation of renal function,and the ADC measurement combined with renal volume measurement would be a clinical feasible modality in the evalution of renal function.Partâ…¢Comparative study of diffusion-weighted imaging in assessing pathological lesion of chronic kidney disease with pathologyObjective:To investigate the value of apparent diffusion coefficient(ADC) measured by DWI in assessing the pathological injures of chronic renal disease(CKD),and to discuss whether or not DWI with navigator-triggered prospective acquisition correction(PACE-DWI) is superior to conventional DWI with breathholding.Materials and methods:Eighty-three patients with CKD intended for renal biopsy and 12 healthy volunteers underwent the DWI examination using both a single-shot spin-echo-planar sequence within a single breath-hold and a spin-echo echo-planar sequence with PACE at b values of 300 and 800 s/mm².Renal biopsy results were reviewed together by two experienced renal pathologists to score the pathological injures of CKD.Finally,71 patients and 12 healthy volunteers were enrolled into further analysis of this study.The bivariate correlation test of Pearson,One-way analysis of variance(ANOVA) and receiver operationg characteristics analysis were used to discuss the value of ADCs in assessing the degree of renal pathological lesions,as well as predicting the moderate and severe degree of renal pathological lesions.Besides,two independent-samples T test and ANOVA were used to compare the ACDs among different pathological types of CKD and different Lee's grades of IgA nephropathy.In addition,multiple linear regression analysis was used to find out the independent influential factors of ADC.Results:The ADCs of right renal parenchyma decreased as the aggravation of renal pathological lesions.There was a significant negative correlation between the ADCs of right renal parenchyma and its pathological scores.The largest negative correlation coefficient was obtained for PACE-DWI with b value 800 s/mm²(r=-0.632,P=0.000). The renal ADC was also a significant predictor of moderate and severe renal pathological lesions for PACE-DWI with b value 800 s/mm²,with an area under the curve of 0.806(P=0.000).The ADCs of right renal parenchyma among four different primary glomerulonephritis types were significant different for PACE-DWI with b value 800 s/mm²(F=4.164,P=0.016).The ADCs of sclerotic glomerulonephritis was significant lower than those of membranous nephropathy and focal segment nephritis (P＜0.05).There was a statistically significant difference among the ADCs of different Lee's grades(P＜0.01).The ADC of fourth grade was significant lower than those of second grade and third grade(P＜0.01).The multiple linear regression analysis showed that the significant linear regression was only observed between pathological scores and ADCs(P＜0.05),not for age and GFR.Conclusion:DWI can be used to assess the degree of pathological injures in CKD. Moreover,PACE-DWI with high b value is superior to conventional DWI in the evaluation of pathological lesions of CKD.It provides a non-invasive modality for the evaluation of pathological lesions,guiding therapy and follow up of CKD.However, the value of DWI in differentiating pathological types of CKD is limited and need further researches. Partâ…£Clinical study of 3.0T blood oxygenation level-dependent MRI in chronic kidney disease:preliminary experienceObjective:To investigate the advisable maximum TE for 3.0T blood oxygenation level-dependent MRI(BOLD-MRI) in renal R₂^* mearsurement and to further discuss its value in assessing renal oxygenation of chronic renal disease(CKD).Materials and methods:Sixty-one patients with CKD intended for renal biopsy and 13 healthy volunteers accepted the BOLD MRI examination on a GE 3.0T Signa HDx scanner.Multi gradient recalled echo with the echo train length of 6 and 12 was used for BOLD-MRI.The maximum TE were 22.4 and 45.9 ms respectively.Finally, thirteen healthy volunteers and 44 patients were enrolled into further analysis.Among them,the biopsy samples of thirty-nine patients were reviewed together by two experienced renal pathologists to score the pathological injures of CKD.In addition, twenty patients received radionuclide renography examination,and the glomerular filtration rate(GFR) is calculated based on the Gates Method.All images were reviewed by two experienced residents together.The R₂^* values of renal cortex and medulla with the different maximum TE were measured on the R₂^* images using the analysis of histogram.The Wilcoxon matched-pairs signed-ranks test was used to compare the difference of R₂^* between renal cortex and medulla in normal kidneys. The repetitive measured R₂^* by 3.0T BOLD-DWI with different maximum TE were compared using the matched-pairs T test,the Bland-Altman plot and Concordance correlation coefficient.R₂^* was measured only with the echo train length of 6 in patients with CKD.The Mann-Whitney U test was used to compare the R₂^* difference between normal group and CKD group.One-way analysis of variance(ANOVA) was used to compare the difference of R₂^* among different stages of renal function.The bivariate correlation test of Spearman was used to analyze the correlation of R₂^* and scores of pathological lesions of right kidney as well as the split R₂^* and GFR.Results:On the R₂^* images,renal cortex could be clearly differentiated from medulla with a color change from blue to green,yellow till red.The R₂^* of renal medulla was remarkably higher than that of renal cortex.There was a significant difference between the R₂^* of renal cortex and medulla(P＜0.01)while there was no significant difference between the R₂^* of renal cortex with two maximum TE(P＞0.05).Besides, the absolute differences and the limits of agreement of repetitive measured R₂^* by 3.0T BOLD-MRI with two maximum TE were -0.3 sec^-1 and -1.9～1.4 sec^-1,and there was a high concordance between repetitive measured R₂^*(ρ_c=0.983,P=0.000).The average R₂^* of renal cortex of both sides in the normal was significantly higher than that in CKD,as well as for the average R₂^* of renal medulla(P＜0.01).Moreover,the average R₂^* of renal medulla increased with the clinical stage of CKD,and there was a statistical difference among different stages of CKD.The average R₂^* of renal medulla of stage 1 is significant higher than that of stage 2 to 4(P＜0.05).A significant negative correlation between R₂^* of renal medulla and GFR(r=-0.415, P=0.008) and a significant positive correlation between R₂^* of renal medulla and scores of pathological lesions were found(r=0.450,P=0.004).Conclusion:3.0T BOLD-MRI with the echo train length of 6(the maximum TE of 22.4 ms) is adequate for the renal R₂^* measurementand can detect hypoxia of CKD, which have potential advantages in the evaluation of renal oxygenation as a noninvasive modality.