MR Urography Research Articles

MR urography evaluation of obstructive uropathy

MR urography evaluation of obstructive uropathy

Diffusion-weighted magnetic resonance imaging of urinary epithelial cancer with upper urinary tract obstruction: preliminary results

Various malignant tumors of the body show high signal intensity on diffusion-weighted magnetic resonance imaging (DWI). In the genitourinary region, DWI is expected to have a role in detecting urinary epithelial cancer noninvasively. To demonstrate the feasibility of DWI for the diagnosis of urinary epithelial cancer with upper urinary tract obstruction. Twenty upper urinary tract cancers in 16 patients were evaluated by high-b-value DWI (b=800 s/mm(2)). The signal intensity was visually evaluated, and the apparent diffusion coefficients (ADCs) were measured. All urinary epithelial cancers showed high signal intensity on DWI. The ADC in cancerous lesions was 1.31+/-0.27 x 10(-3) mm(2)/s, which was significantly lower than that of the lumens of the ureter or renal pelvis (3.32+/-0.44 x 10(-3) mm(2)/s; P<0.001). Maximum intensity projection images of DWI in combination with static-fluid MR urography provided three-dimensional entire urinary tract imaging with the extension of tumors. DWI is useful in the tumor detection and in evaluating the tumor extension of urinary epithelial cancer in patients with upper urinary tract obstruction.

MR urography for suspected upper tract urothelial carcinoma

The key components of the MR urography protocol for suspected upper tract urothelial carcinoma are coronal T2-weighted hydrographic sequences without contrast agent and coronal gadolinium-enhanced T1-weighted 3D-spoiled gradient-recalled echo in nephrographic and pyelographic phases. Upper tract urothelial carcinomas can be categorized into papillary tumor, flat tumor, and infiltrative tumor based on the growth pattern and extent. Papillary lesions appear as small filling defects of soft tissue signal on T2-weighted hydrographic and T1-weighted pyelographic phase images. On nephrographic phase images, the lesions show homogeneous enhancement. A flat tumor appears as a segmental area of diffuse thickening and enhancement of the urinary tract wall on nephrographic phase images. Infiltrative tumor often appears as a large heterogeneously enhancing mass. MR urography is a promising alternative for CT urography in the evaluation of upper tract urothelial carcinoma, especially when the patient has a contraindication to iodinated contrast material.

Appearance of Deflux® implants with magnetic resonance imaging after endoscopic treatment of vesicoureteral reflux in children

With the increasing popularity of endoscopic treatment for vesicoureteral reflux (VUR) in children, dextranomer/hyaluronic acid copolymer (Deflux) implants are more frequently detected by magnetic resonance imaging (MRI). Such findings on MRI may be misinterpreted and lead to unnecessary intervention. The objective of this study was to characterize the appearance of Deflux implants on MRI. Between July 2001 and November 2007, hospital charts of patients with a history of Deflux injection for VUR were evaluated to identify those who had subsequent MRI studies. The indications were determined, and the appearance of Deflux implants analyzed and compared to findings on ultrasound, voiding cystourethrography and kidney ureter bladder radiography. Of 893 patients who underwent endoscopic treatment for VUR, subsequently 16 patients (1.8%) had MRI scans. Twenty-seven Deflux implants were identified on MRI as bright structures on T2-weighted sequences only. Neither T1-weighted images nor excretory MR urography visualized the Deflux implants, which did not enhance with gadolinium. Deflux was not detected by kidney ureter bladder radiography; however, voiding cystourethrography and more reliably ultrasound could identify implants. Deflux implants appear on MRI as bright structures on T2-weighted sequences. History of VUR/VUR treatment and the presence of a single urinary system should provide reassurance and prevent inappropriate intervention for misdiagnosed ureteroceles.

Time‐resolved dynamic contrast‐enhanced MR urography for the evaluation of ureteral peristalsis: Initial experience

To determine the feasibility of time-resolved dynamic contrast-enhanced magnetic resonance urography (MRU) for the evaluation of ureteral peristalsis using a data-sharing 3D gradient echo sequence with spiral k-space filling. Eight patients (M=3, F=5, mean 48.1 years) were referred for MRU for the evaluation for renal mass (n=3), hematuria (n=2), urinary tract tuberculosis (n=1), postoperative bladder cancer (n=1), and postoperative ureteric reimplantation (n=1). Dynamic MRU was performed for 120 seconds at 1.5T after intravenous furosemide and gadolinium administration using an oblique sagittal, time-resolved T1 3D gradient echo sequence with 1 second effective temporal resolution. Study quality was assessed based on artifacts and extent of ureteric visualization. Frequency of peristalsis from the renal pelvis to urinary bladder was evaluated for each subject. A total of 16 ureters were examined. Image quality was good in four ureters, satisfactory in 11 ureters, and poor in one ureter. Mean peristaltic frequency was 3.5 waves per minute (range, 2.5-6.5 waves/minute) in normal ureters (n=11). Five ureters were considered abnormal (one urinary tract tuberculosis and four postsurgical ureters), and all had decreased or no peristalsis (0-1.5 waves per minute). MRU using a time-resolved, data-sharing 3D contrast-enhanced technique is able to demonstrate ureteral peristalsis and permits quantification of ureteral peristaltic frequency.

Potential of MR-imaging in the paediatric abdomen

Objective To describe the potential and relevant applications of MR-imaging (MRI) in typical paediatric abdominal conditions and diseases. Method The commonly used indications, applications, and sequences as well as typical imaging findings of paediatric abdominal MRI are presented and discussed, with emphasis on specific paediatric needs and queries. Only applications as used in routine clinical work are listed, other more sophisticated and advanced techniques will only briefly be mentioned. Furthermore, some aspects of paediatric MR Urography are presented and discussed. Conclusion Though conventional imaging methods (ultrasound and plain film) are valuable and – particularly in the paediatric abdomen – form the mainstay of routine imaging in paediatric abdominal radiology, some conditions require sectional imaging. MRI is increasingly applied to these queries in neonates, infants and children as an alternative method to CT without any radiation burden, and – when performed adequately and skilfully – can answer most treatment relevant questions. MR will increasingly be applied with new applications and broader availability also with functional information deriving from new equipment and research offering an ideal one stop imaging approach to many conditions also in children.

Intraindividual Comparison of Image Quality in MR Urography at 1.5 and 3 Tesla in an Animal Model

Experimental evaluation of image quality of the upper urinary tract in MR urography (MRU) at 1.5 and 3 Tesla in a porcine model. In this study four healthy domestic pigs, weighing between 71 and 80 kg (mean 73.6 kg), were examined with a standard T1w 3D-GRE and a high-resolution (HR) T1w 3D-GRE sequence at 1.5 and 3 Tesla. Additionally, at 3 Tesla both sequences were performed with parallel imaging (SENSE factor 2). The MR urographic scans were performed after intravenous injection of gadolinium-DTPA (0.1 mmol/kg body weight (bw)) and low-dose furosemide (0.1 mg/kg bw). Image evaluation was performed by two independent radiologists blinded to sequence parameters and field strength. Image analysis included grading of image quality of the segmented collecting system based on a five-point grading scale regarding anatomical depiction and artifacts observed (1: the majority of the segment (>50%) was not depicted or was obscured by major artifacts; 5: the segment was visualized without artifacts and had sharply defined borders). Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were determined. Statistical analysis included kappa-statistics, Wilcoxon and paired student t-test. The mean scores for MR urographies at 1.5 Tesla were 2.83 for the 3D-GRE and 3.48 for the HR3D-GRE sequence. Significantly higher values were determined using the corresponding sequences at 3 Tesla, averaging 3.19 for the 3D-GRE (p = 0.047) and 3.92 for the HR3D-GRE (p = 0,023) sequence. Delineation of the pelvicaliceal system was rated significantly higher at 3 Tesla compared to 1.5 Tesla (3D-GRE: p = 0.015; HR3D-GRE: p = 0.006). At 3 Tesla the mean SNR and CNR were significantly higher (p < 0.05). A kappa of 0.67 indicated good interobserver agreement. In an experimental setup, MR urography at 3 Tesla allowed for significantly higher image quality and SNR compared to 1.5 Tesla, particularly for the visualization of the pelvicaliceal system.

In Vitro Assessment of a 3D Segmentation Algorithm Based on the Belief Functions Theory in Calculating Renal Volumes by MRI

Renal volumetry is an essential part of split renal function assessment in MR urography. The aim of this study was to assess the accuracy and repeatability of a 3D segmentation algorithm based on the belief functions theory for calculating renal volumes from MR images. The true volumes of 20 animal kidneys of various sizes were obtained by fluid displacement. Each kidney was examined using two different MR units. Three-dimensional proton density-weighted acquisitions with an incremental slice thickness were performed. The MR volume was then measured with a segmentation algorithm based on the belief functions theory. Two independent observers performed all segmentations twice. Accuracy, intraobserver variability, and interobserver variability were evaluated by the Bland-Altman method. The number and type of manual corrections were recorded as well as the entire processing time. The mean renal volume estimated by fluid displacement was 114 mL (range, 38-224 mL). With regard to the renal volumes obtained from assessments of adjacent axial MR images, the maximal SDs of the difference were 2.2 mL (accuracy), 0.6 mL (intraobserver variability), and 1.8 mL (interobserver variability). Segmentation of axial slices provided better accuracy and reproducibility than coronal slices. Overlapped coronal slices yielded poor results because of the partial volume effect. The mean processing time including optional manual modifications was less than 75 seconds. The belief functions theory can be considered an accurate and reproducible mathematic method to assess renal volume from MR adjacent images.

MR urography: anatomy and physiology

MR urography: anatomy and physiology

Partial Unilateral Ureteral Obstruction in Newborn Mice: Magnetic Resonance Imaging and Pathology Studies

The mechanism underlying the evolution of congenital obstructive hydronephrosis in humans is still unclear. Although partial unilateral ureteral obstruction has been extensively explored in rats, studies in neonatal mice may lead to new insights into underlying cellular mechanisms, especially with the availability of mutant mice. We developed a model of partial unilateral ureteral obstruction in newborn mice. Mice were operated on by the fifth day of life. We created 3 groups, namely partial unilateral ureteral obstruction (embedding the ureter in the psoas muscle), complete unilateral ureteral obstruction (ligating the ureter) and sham (exposing the ureter). We studied pelvis diameter and kidney length on magnetic resonance imaging, and kidney weight, inflammation, apoptosis and fibrosis on histological assessment during the second (early) and fourth weeks (late) postoperatively. Magnetic resonance imaging showed enlarged pelvis diameter in late partial unilateral ureteral obstruction, and in early and late complete unilateral ureteral obstruction. Pathological studies revealed parenchyma atrophy in early and late partial unilateral ureteral obstruction. Apoptosis occurred early in partial unilateral ureteral obstruction and decreased later. Macrophage infiltration was enhanced in early and late partial unilateral ureteral obstruction. Fibrosis increased in late partial unilateral ureteral obstruction. All of these results were significantly intermediate between mice with complete unilateral ureteral obstruction and sham operated mice. It is possible to create renal lesions in newborn mice specific to partial ureteral obstruction. Magnetic resonance imaging of morphological changes demonstrated specific features of partial unilateral ureteral obstruction. Being noninvasive, this approach opens the way for further studies to investigate prognostic parameters after partial ureteral obstruction. In the future this model could be used in knockout mice to study the pathogenesis of renal lesions secondary to obstruction.

Static T2w MRU in Noncalcular Urinary Obstruction: Comparison of Its Two Techniques

The purpose of this study was to compare the diagnostic accuracy of T2-weighted (T2w) MR urography (MRU) techniques — the standard MRU using fast spin echo (FSE) and postprocessing maximum intensity projection (MIP) and the single-shot MRU — in the diagnosis of ureteric obstruction in patients with noncalcular urinary obstruction. The study included 150 patients admitted to our center between January 2005 and December 2006. There were 203 renal units with noncalcular obstruction; 53 patients had bilateral obstruction. Patients with calcular obstruction were excluded. There were 85 males and 65 females with a mean age of 50 (range: 5–83) years. All patients were examined with static MRU using both single-shot (thick slab) and multisection MRU. Using single-shot MRU, we obtained images at the direct coronal and oblique coronal, as well as sagittal, planes for each renal unit. Postprocessing MIP for the standard coronal heavy T2 source images to obtain coronal and oblique images was done. Among the obstructed 203 units, the intrinsic causes were present in 157 units (151 were stricture and six were ureteric tumors), while the extrinsic causes were present in 46 units (35 bladder tumor, four ureterocele, five retroperitoneal fibrosis, one prostatic tumor, and one local pelvic recurrence after radical cystectomy for bladder cancer). The overall accuracy of single-shot MRU was 89% and was 93% for the multisection MRU in cases of intrinsic ureteric obstruction, while in cases of extrinsic obstruction, it was 20% for single-shot MRU and 96% for multisection MRU. T2w static MRU is a very useful technique in diagnosing noncalcular ureteric obstruction. Multisection MRU has a high diagnostic accuracy and reliability over that of the single-shot technique. The single-section technique is very rapid and useful in diagnosing ureteric stricture so it could be used as a localizer, while multisection images with postprocessing MIP is mandatory, especially in cases of suspected ureteric tumors or extraureteric causes.

MR Urography: Improved Visualization of the Urinary Collecting System Using a Negative Oral Contrast Agent

MR Urography: Improved Visualization of the Urinary Collecting System Using a Negative Oral Contrast Agent

MR urography evaluation of obstructive uropathy

Hydronephrosis and the evaluation of obstructive uropathy are the most common indications for MR urography in our practice. Typically our patients fall into one of two groups: infants with antenatal hydronephrosis and older children who present with abdominal pain, hematuria or urinary tract infection. Obstruction in children is usually chronic and partial. Intermittent episodes of increased pressure occur when the urine production exceeds the capacity for drainage. MR urography uses a fluid and diuretic challenge to assess the hydronephrotic kidney. High-quality anatomic images provide a morphologic assessment of the hydronephrotic system. Although it is relatively straightforward to determine if a system is not obstructed on the basis of the renal transit time (RTT), no single parameter is adequate to fully characterize obstruction. By evaluating the changes in signal intensity in the renal parenchyma following contrast administration, the hydronephrotic systems are classified as compensated or decompensated. Delayed RTT and the presence of urine-contrast levels indicate stasis. Calyceal transit time and the difference between the volumetric and the Patlak differential renal function (vDRF-pDRF) are measures of the physiologic changes within the kidney. Additionally, MR urography provides prognostic information by assessing the quality of the renal parenchyma and identifying uropathy preoperatively. MR urography combines both anatomic and functional information in a single test and is capable of providing a comprehensive evaluation of obstructive uropathy that could ultimately help select those patients most likely to benefit from surgical intervention.

Evaluation of UPJ obstruction before and after pyeloplasty using MR urography

This article builds on the previous article in this symposium and shows how MR urography contributes to the postoperative evaluation of children with UPJ obstruction. By analyzing the postoperative results, we derived new insights into their preoperative evaluation. With MR urography we combine simultaneous physiological and anatomic evaluation that enables us to identify changes in renal pathophysiology that occur in association with impaired drainage and obstruction. We studied 35 children before and after pyeloplasty. The pyeloplasty was considered successful in 30 and unsuccessful in 5. Both anatomic and functional criteria were used. The anatomic parameters included the degree of hydronephrosis, the appearance of the renal parenchyma, the quality of the nephrogram and the presence of crossing vessels. The functional criteria included the renal transit time, the calyceal transit time, the volumetric differential function, the Patlak differential function, the difference between the volumetric and Patlak differential function and the Patlak number per milliliter of renal tissue. No single parameter was sufficient to fully characterize UPJ obstruction, but by synthesizing all the information we were able to subdivide UPJ obstruction into compensated, decompensated and uropathic kidneys. Decompensated systems had the most significant improvement following successful pyeloplasty. Compensated systems showed little improvement in renal function, and uropathic kidneys were associated with a poor prognosis. It is clear that not all UPJ obstructions are the same, and it seems logical that treatment should be individually tailored rather than using a standard approach for all cases. Because MR urography can identify pathophysiological differences in children with UPJ obstruction that are occult to renal scintigraphy, it has an important potential role in identifying those who will benefit most from pyeloplasty and those who are probably best observed.

Evaluation of reflux nephropathy, pyelonephritis and renal dysplasia

MR urography has the potential to significantly improve our understanding of the relationship between reflux nephropathy, pyelonephritis, vesicoureteric reflux and renal dysplasia. MR urography utilizes multiple parameters to assess both renal anatomy and function and provides a more complete characterization of acquired and congenital disease. Pyelonephritis and renal scarring can be distinguished by assessing the parenchymal contours and signal intensity. Characteristic imaging features of renal dysplasia include small size, subcortical cysts, disorganized architecture, decreased and patchy contrast enhancement as well as a dysmorphic pelvicalyceal system. Because of its ability to subdivide and categorize this heterogeneous group of disorders, it seems inevitable that MR urography will replace DMSA renal scintigraphy as the gold standard for assessment of pyelonephritis and renal scarring. MR urography will contribute to our understanding of renal dysplasia and its relationship to reflux nephropathy.

MR urography in children: how we do it

In this article we introduce the topic of MR urography in children, focusing on the details required to obtain consistently high-quality scans. Much of the information presented is based on our experience during the last 7 years. We have performed almost 1,000 MR urograms in children, and the technique has evolved considerably during this time. We have learned through trial and error and have improved our protocols to the point that our approach is now standardized and reliably generates high-quality studies. From this standardized protocol, further refinements in technique can be readily implemented. It is important to remember that this clinical application is in its infancy and will improve significantly with further technical development. This paper provides an overview of the practical issues associated with obtaining high-quality scans as well as an introduction into the interpretation of MR urograms.

Dystopic dysplastic kidney with ectopic ureter: improved localization by fusion of MR urography and 99mTc-DMSA SPECT datasets

We report a 12-year-old girl with a long history of constant urinary dribbling and apparently only a left kidney. Using a multimodality approach involving the fusion of MR urography and (99m)Tc-dimercaptosuccinic acid (DMSA) SPECT datasets, it was finally possible to exactly localize the very small dystopic, dysplastic right kidney and its ectopic ureter draining into the vagina.

Formen der operativen Harnableitung: Methoden und bildgebende Diagnostik

After cystectomy two principal types of urinary diversion are used for the surgical reconstruction of the urinary tract: incontinent and continent. In the continent type of urinary diversion, a differentiation must be made between those with and without catheterization for voiding. Besides urothelial cancer other reasons for urinary diversion include neurogenic bladder palsy (connatal or acquired) due to meningomyelocele or connatal diseases like bladder exstrophy. The main objective of the clinical urologist when selecting urinary diversion are to achieve continence and to preserve upper urinary tract function. Knowledge of the different forms of urinary diversion is critical for the exact interpretation of the images. This review presents the typical imaging techniques after a description of the basic surgical features of urinary diversion. CT urography and MR urography are becoming increasingly important as further imaging tools for controlling urinary diversions.

Are Patients with Moderate Renal Failure at Risk for Developing Nephrogenic Systemic Fibrosis?

HomeRadiologyVol. 244, No. 3 PreviousNext CommunicationsLetters to the EditorAre Patients with Moderate Renal Failure at Risk for Developing Nephrogenic Systemic Fibrosis?Georges Saab*, Ali Abu-Alfa†Georges Saab*, Ali Abu-Alfa†Author Affiliations*Department of Internal Medicine, Division of Nephrology, University of Missouri-Columbia School of Medicine, One Hospital Drive, Columbia, MO 65211†Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Conn e-mail: [email protected]Georges Saab*Ali Abu-Alfa†Published Online:Sep 1 2007https://doi.org/10.1148/radiol.2443070351MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References1 Public health advisory: update on magnetic resonance imaging (MRI) contrast agents containing gadolinium and nephrogenic fibrosing dermopathy. U.S. Food and Drug Administration Web site. http://www.fda.gov/cder/drug/InfoSheets/HCP/gcca_200612HCP.htm. Accessed February 20, 2007. Google Scholar2 Sadowski EA, Bennett LK, Chan MR, et al. Nephrogenic systemic fibrosis: risk factors and incidence estimation. Radiology 2007;243(1):148–157. Link, Google Scholar3 Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 1999;130(6):461–470. Crossref, Medline, Google Scholar4 Skluzacek PA, Szewc RG, Nolan CR 3rd, Riley DJ, Lee S, Pergola PE. Prediction of GFR in liver transplant candidates. Am J Kidney Dis 2003;42(6):1169–1176. Crossref, Medline, Google Scholar5 Poggio ED, Nef PC, Wang X, et al. Performance of the Cockcroft-Gault and modification of diet in renal disease equations in estimating GFR in ill hospitalized patients. Am J Kidney Dis 2005;46(2):242–252. Crossref, Medline, Google Scholar6 Information for healthcare professionals: gadolinium-based contrast agents for magnetic resonance imaging (marketed as Magnevist, MultiHance, Omniscan, OptiMARK, ProHance). U.S. Food and Drug Administration Web site. http://www.fda.gov/cder/drug/InfoSheets/HCP/gcca_200705.htm. Google ScholarArticle HistoryPublished in print: 2007 FiguresReferencesRelatedDetailsCited ByAmerican Journal of Kidney Diseases, Vol. 76, No. 3Advances in Chronic Kidney Disease, Vol. 18, No. 3Clinical Journal of the American Society of Nephrology, Vol. 5, No. 3What Is the Current Role of CT Urography and MR Urography in the Evaluation of the Urinary Tract?1Stuart G. Silverman, , John R. Leyendecker, , and E. Stephen Amis, Jr, 1 February 2009 | Radiology, Vol. 250, No. 2Journal of Magnetic Resonance Imaging, Vol. 29, No. 4Journal of Magnetic Resonance Imaging, Vol. 30, No. 6Journal of Magnetic Resonance Imaging, Vol. 30, No. 6Clinical Radiology, Vol. 64, No. 7Magnetic Resonance Imaging Clinics of North America, Vol. 17, No. 1Which Study When? Is Gadolinium-enhanced MR Imaging Safer than Iodine-enhanced CT?1Jeffrey C. Weinreb, 1 October 2008 | Radiology, Vol. 249, No. 1European Radiology, Vol. 18, No. 10Pediatric Nephrology, Vol. 23, No. 12Journal of the American College of Radiology, Vol. 5, No. 1Investigative Radiology, Vol. 43, No. 1Journal of Medical Imaging and Radiation Oncology, Vol. 52, No. 4Recommended Articles A Systematic Review of 639 Patients with Biopsy-confirmed Nephrogenic Systemic FibrosisRadiology2019Volume: 292Issue: 2pp. 376-386Use of Intravenous Gadolinium-based Contrast Media in Patients with Kidney Disease and the Risk of Nephrogenic Systemic Fibrosis: Radiology In TrainingRadiology2021Volume: 300Issue: 2pp. 279-284Effect of Intravenous Administration of Contrast Media on Serum Creatinine Levels in NeonatesRadiology2017Volume: 284Issue: 2pp. 530-540Notice of Withdrawal: MR Imaging and Gadolinium: Reassessing the Risk of Nephrogenic Systemic Fibrosis in Patients with Severe Renal DiseaseRadiology2018Volume: 286Issue: 1Renal Allograft Dysfunction: Evaluation with Shear-wave SonoelastographyRadiology2018Volume: 288Issue: 1pp. 146-152See More RSNA Education Exhibits Gadolinium Deposition and NSF: Should I Be Worried?Digital Posters2018State of the Art: Imaging of Vascular Pathology Using Ferumoxytol, A Novel MR Contrast AgentDigital Posters2020Non-Gadolinium Contrast Enhanced MRA: Pictorial Review of Vascular Applications of Ferumoxytol in MR ImagingDigital Posters2020 RSNA Case Collection Acute Aortoiliac Occlusion RSNA Case Collection2021Renal Transplant ATNRSNA Case Collection2020Renal Medullary NephrocalcinosisRSNA Case Collection2021 Vol. 244, No. 3 Metrics Altmetric Score PDF download

MRI of the kidney—state of the art

Ultrasound and computed tomography (CT) are modalities of first choice in renal imaging. Until now, magnetic resonance imaging (MRI) has mainly been used as a problem-solving technique. MRI has the advantage of superior soft-tissue contrast, which provides a powerful tool in the detection and characterization of renal lesions. The MRI features of common and less common renal lesions are discussed as well as the evaluation of the spread of malignant lesions and preoperative assessment. MR urography technique and applications are discussed as well as the role of MRI in the evaluation of potential kidney donors. Furthermore the advances in functional MRI of the kidney are highlighted.