No abstract

Ultrasound measured renal length and CT measured renal volume are potential surrogate markers for single kidney glomerular filtration rate (SKGFR). The aims of this study are to determine: (1) the repeatability of ultrasound measured length and low radiation dose spiral CT measured volume; (2) the relationship between renal length and volume; and (3) whether length and/or volume is a predictor of SKGFR. 69 patients with suspected renal artery stenosis underwent ultrasound renal length measurement, CT evaluation of renal volume and assessment of SKGFR. 40 patients had ultrasound measurement of length and CT evaluation of volume performed twice on two separate visits. 25 patients also had ultrasound measured renal parenchymal thickness and area. The region of interest was drawn around the kidneys and a threshold set to subtract renal peripelvic fat and renal pelvis. The volume from each slice was summed to obtain the total volume for each kidney. The limits of agreement for ultrasound measured renal length were -1.6 cm to 1.52 cm and that for CT renal volume were -33 ml to 32 ml. There was significant correlation between ultrasound measured length and CT volume (r=0.74, p<0.01). Volume was a better predictor of SKGFR (r(2)=0.57) than length (r(2)=0.48). The combined parameters of ultrasound measured length, area and parenchymal thickness were a better predictor of volume (r(2)=0.81) and SKGFR (r(2)=0.58) than ultrasound measured length on its own. The low dose CT technique was reasonably reproducible and renal volume measurements correlate better with SKGFR than length. Ultrasound predictions of renal volume and SKGFR can be improved by incorporating cross-sectional area and parenchymal thickness. Further investigation is required to refine our low dose CT technique.

No abstract

No abstract

The renin-angiotensin system is likely to be important in the progression of renal diseases because of its effect on tissue hemodynamics and glomerular cell function. Recent evidence from small studies has suggested a possible role for the genetic determinants of angiotensin converting enzyme activity in the rate of progression of renal failure. We studied the effect of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme gene on the rate of renal function deterioration in 822 patients with a variety of renal diseases. We found that the slope of the reciprocal serum creatinine-versus-time plot was steeper in patients homozygous for the deletion allele (DD) compared with those homozygous for the insertion allele (II) (P = .015). When patients with similar renal function at presentation (creatinine < 200 mumol/L) were compared, II homozygotes had significantly improved renal survival (P = .039). Separate analyses of patients with glomerular diseases and tubulointerstitial diseases demonstrated an effect of this genotype in glomerular diseases only. These data provide further evidence of the possible role of the angiotensin-converting enzyme gene in the rate of progression of renal failure, although further studies are required to evaluate the role of this and other proposed candidate genes in renal diseases.