Chronic Urinary Obstruction: Evaluation of Dynamic Contrast-enhanced MR Urography for Measurement of Split Renal Function

Abstract

).q RSNA, 2014 Purpose:To evaluate if measurement of split renal function (SRF) with dynamic contrast material-enhanced (DCE) magnetic resonance (MR) urography is equivalent to that with renal scintigraphy (RS) in patients suspected of having chronic urinary obstruction. Materials and Methods:The study protocol was approved by the institutional ethics committee of the coordinating center on behalf of all participating centers. Informed consent was obtained from all adult patients or both parents of children. This prospective, comparative study included 369 pediatric and adult patients from 14 university hospitals who were suspected of having chronic or intermittent urinary obstruction, and data from 295 patients with complete data were used for analysis. SRF was measured by using the area under the curve and the Patlak-Rutland methods, including successive review by a senior and an expert reviewer and measurement of intra-and interobserver agreement for each technique. An equivalence test for mean SRF was conducted with an a of 5%. Results:Reproducibility was substantial to almost perfect for both methods. Equivalence of DCE MR urography and RS for measurement of SRF was shown in patients with moderately dilated kidneys (P , .001 with the Patlak-Rutland method). However, in severely dilated kidneys, the mean SRF measurement was underestimated by 4% when DCE MR urography was used compared with that when RS was used. Age and type of MR imaging device had no significant effect. Conclusion:For moderately dilated kidneys, equivalence of DCE MR urography to RS was shown, with a standard deviation of approximately 12% between the techniques, making substitution of DCE MR urography for RS acceptable. For severely dilated kidneys, a mean underestimation of SRF of 4% should be expected with DCE MR urography, making substitution questionable.q RSNA, 2014

Renal Functional MRI and Its Application

“…Chronic urinary obstruction can show split renal function (SRF), which is defined as a quantity associated with the function of a single kidney. In patients with moderately hydronephrotic kidneys, the accuracy of DCE‐MRI urography for SRF measurements can be equivalent to that of renal scintigraphy (RS) . Inflammatory renal conditions (such as pyelonephritis and abscess) also decrease ADC values because of edema, increased cellularity, and fibrosis.…”

Estimation of Split Renal Function With 99mTc-DMSA SPECT: Comparison Between 3D Volumetric Assessment and 2D Coronal Projection Imaging

“…SRF can be estimated with renal scintigraphy performed with various radionuclides, including 99m Tc-labeled dimercaptosuccinic acid ( 99m Tc-DMSA), 99m Tc-labeled mercaptoacetyltriglycine ( 99m Tc-MAG3), and 99m Tc-labeled diethylenetriaminepentaacetate ( 99m Tc-DTPA) [1–4]. Other noninvasive modalities and procedures for calculating SRF include CT angiography [3, 5], dynamic contrast-enhanced MR urography [6], and DWI [7]. Among these, 99m Tc-DMSA renal scintigraphy has been considered the most sensitive method for proving the existence of parenchymal damage due to acute or chronic pyelonephritis and acquiring data on differential kidney function [4, 8, 9].…”

Dynamic MRI and isotope renogram in the functional evaluation of pelviureteric junction obstruction: A comparative study

“…However, even when isotope renogram results are compromised by reduced radiotracer uptake in the affected kidney, dMRI has proved to be a very good modality to differentiate between an obstructed dilated and a non-obstructed upper urinary tract. [19] However, a large multi-center study published in 2014 by Claudon et al [20] showed that dMRI was equivalent to renal scintigraphy in moderately dilated kidneys; but dMRI underestimated split renal function by 4% in severely dilated kidneys, making substitution of renal scintigraphy questionable. The advantages of MRI over other radiological techniques are exquisite soft tissue characterization, capability of direct multiplanar and three dimensional reformatting images, and lack of ionizing radiation.…”