Increases in kidney volume in autosomal dominant polycystic kidney disease can be detected within 6 months

Abstract

Kidney volume growth is considered the best surrogate marker predicting the decline of renal function in autosomal dominant polycystic kidney disease. To assess the therapeutic benefit of new drugs more rapidly, changes in kidney volume need to be determined over a short time interval. Here we measured renal volume changes by manual segmentation volumetry applied to magnetic resonance imaging scans obtained with an optimized T1-weighted acquisition protocol without gadolinium-based contrast agents. One hundred young patients with autosomal dominant polycystic kidney disease and preserved renal function had a significant increase in total kidney volume by 2.71+/-4.82% in 6 months. Volume measurements were highly reproducible and accurate, as indicated by correlation coefficients of 1.000 for intra-observer and 0.996 for inter-observer agreement, with acceptable within-subject standard deviations. The change in renal volume correlated with baseline total kidney volume in all age subgroups. Total kidney volume positively correlated with male gender, hypertension, albuminuria and a history of macrohematuria but negatively with creatinine clearance. Albuminuria was associated with accelerated volume progression. Our study shows that increases in kidney volume can be reliably measured over a 6 month period in early autosomal dominant polycystic kidney disease using unenhanced magnetic resonance imaging sequences.

Soluble Klotho and Autosomal Dominant Polycystic Kidney Disease

“…As expected, patients with CKD1-2 had higher urinary albumin excretion, and patients with XLH were predominantly female and had lower height than the other groups. The kidneys of the healthy volunteers were normal per ultrasonography, with a mean total kidney volume of 360 cm 3 . None of the ADPKD1-2 patients, CKD1-2 patients, or volunteers received nutritional or activated vitamin D metabolites, calcium supplementation, phosphate binders, or bisphosphonates, but most of the patients with XLH were receiving treatment with calcitriol and phosphate supplements (for details, see the Methods section).…”

“…Total kidney volumes were estimated from magnetic resonance imaging sequences, as reported elsewhere (3). The healthy volunteers underwent renal ultrasonography, and their kidney volumes were estimated by applying the ellipsoid formula (25).…”

“…Patients with ADPKD1-2 had a mean 6 SD total kidney volume of 9706533 cm 3 and a mean total cyst volume of 5616426 cm 3 . The annual mean absolute and percentage kidney growth rates were 78698 cm 3 and 6.3%66.9% per year, respectively.…”

“…Between age 20 and 40 years, the cysts replace approximately 50% of the normal parenchyma (3). In most patients, GFR remains preserved up to age 40 because glomerular hyperfiltration of remaining nephrons compensates for the ongoing loss of functional renal tissue (4,5).…”

Kidney Volume and Functional Outcomes in Autosomal Dominant Polycystic Kidney Disease

“…Imaging methods that reliably and accurately measure TKV in ADPKD patients have been developed utilizing magnetic resonance imaging (MRI) and computerized tomography (4,5,(16)(17)(18)(19)(20)(21)(22). The Consortium for Radiologic Imaging Studies of PKD (CRISP) (ClinicalTrials.gov identifier NCT 01039987) has developed reliable and accurate MRI-based protocols to measure TKV in ADPKD patients that detect relatively small changes in TKV over a short period of time (19,20).…”