Evaluation of renal function by ^99mTc-DTPA renal dynamic imaging in different stages of polycystic kidney disease

Objectives: To investigate the application value of ^99mTc-DTPA renal dynamic imaging (gGFR) for GFR detection and renogram in different stages of polycystic kidney diseases.

Methods: We chose 59 confirmed non-dialysis cases of polycystic renal patients who have undergone renal dynamic imaging and double plasma method to measure GFR in my section.According to the guideline of NKF-K/DOQI^[1], stages of chronic kidney disease(CKD), they were divided into 3 groups by the gold standard method^[2] of double plasma (dGFR): Group A: GFR≥60ml/(min·1.73m²) (including CKD1~2 stage,19 cases); Group B: 60ml/(min·1.73m²)>GFR≥30ml/(min·1.73m²) (including CKD3 stage, 23 cases); Group C: GFR<30ml/(min·1.73m²) (including CKD4~5 stage, 17 cases). The Gate’s method was matched with the gold standard method for t-test and Pearson correlation analysis and ROI technique was used to display 20 minutes renogram of the double kidney.

Results: 1. There was no significant difference between Gate’s method and gold standard method in group A and group B (t = 1.255, -0.061 respectively, all P> 0.05) and there was a significant correlation between Gate’s method and gold standard method in these groups (r = 0.55,0.62 respectively, all P <0.05); On the renogram of the double kidneys, the concentration peak, transfer and excretion of radiation in the double kidney were shown effectively. 2. In group C, there was a significant difference (t = -2.132,P<0.05)and no significant correlation (r = 0.36,P> 0.05) between the two methods. The renogram of group C can’t be analyzed effectively.

Conclusions: The renal dynamic imaging and Gate’s method can evaluate the renal function in the early stage of polycystic renal disease (CKD1~3 stage) effectively, and suitable renogram of double kidneys could be also obtained. But it is not appropriate in the late stage (CKD4~5 stage). These results may be due to the following reasons: 1. With the increase of the volume and amount of unfunctional vesicles, more and more normal kidneys are squeezed and atrophied. When outlining the ROI of the kidney, the actual boundaries of the kidneys are not clear, so the ROI of the kidney was easy to be oversize and overestimate GFR in stage CKD4~5 stage [GFR<30ml/(min·1.73m²)]. 2. Most of the patients combined with polycystic liver and polycystic spleen, some kidney tissues overlap with the liver and spleen on the front-back positions. When outlining the ROI of the kidney, it is inevitable that a part of the liver or spleen region will be included, which in turn overestimates GFR. 3. With the progress of the disease, polycystic kidney depth has changed, which will have an impact on the accuracy of GFR. Key words: Polycystic Kidney Diseases; Glomerular filtration rate; Renal dynamic imaging; Gate’s method;