Magnetic Resonance Imaging in Acute and Chronic Kidney Diseases: Present Status

Abstract

Magnetic resonance imaging (MRI) of normal and diseased kidneys shows great promise because of the combined value of anatomical and functional information provided, as well as of specific contrast patterns that can be observed non-invasively. Multicontrast MRI is able to show infiltrative kidney disorders. Diffusion-weighted imaging can assess alterations in renal function and can suggest obstruction or inflammation when present. Due to the low nephrotoxicity, contrast-enhanced MR studies using serial dynamic enhancement with non-specific gadolinium chelates are able to provide information on glomerular filtration. Furthermore, contrast agents such as ultrasmall particles of iron oxide, specific of inflammation, should be used in the near future to detect active from quiescent involvement, both in native kidneys and renal allografts. Early results should indicate that these compounds might differentiate acute tubular necrosis from other acute nephropathies, as well as active proliferative nephropathies from chronic ones. Ongoing studies will obviously demonstrate the value of the combination of these various MRI sequences in the diagnosis of acute renal failure and chronic kidney disease.

Blood oxygen level-dependent and perfusion magnetic resonance imaging: detecting differences in oxygen bioavailability and blood flow in transplanted kidneys

“…The oxyhemoglobin saturation dissociation curve suggests that at PaO2 values above 40 mmHg, as in the renal cortex, the curve is relatively flat and changes in the PaO2 result in small changes in oxyhemoglobin saturation. However between PaO2 of 10 and 40 mmHg, as in the renal medulla, changes in PaO2 result in large changes in oxyhemoglobin saturation [38]. Therefore small alterations in PaO2 in the medulla cause changes in oxyhemoglobin concentrations detectable by BOLD MR imaging.…”

“…Lastly, while our perfusion MR measurements in the cortex and medulla of transplanted kidneys are consistent with accepted values published in the literature [10], the model used to estimate perfusion (Appendix A) assumes contrast agent does not leave the vascular space during the first pass. However, filtration of gadolinium is known to occur instantaneously, and during the first pass up to 20 percent is filtered in a normally functioning kidney [38]. This is a constant that can potentially be related to the subject’s serum creatinine.…”

Role of imaging in the evaluation of renal dysfunction in heart failure patients

“…Magnetic resonance imaging (MRI) offers the optimal combination between spatial resolution and functional evaluation, in other words between a structural and a functional study[50,51]. Furthermore, it avoids the use of iodinated contrast media and radioisotopes, which is obviously of great advantage in patients suffering from CKD.…”

Magnetic resonance imaging of urea transporter knockout mice shows renal pelvic abnormalities

“…While computed tomography is the main modality used for clinical imaging of the kidney, magnetic resonance imaging (MRI) is comparable in identification of renal lesions [8], and can provide a wide range of morphologic and functional information through techniques such as diffusion weighted imaging, dynamic contrast enhanced imaging, size selective contrast agents, and angiography [9;10]. Indeed, MRI has widespread application in the assessment of kidney disease, including visualization of cysts, tumors, obstructive uropathy, and vasculature [9;10].…”

“…Indeed, MRI has widespread application in the assessment of kidney disease, including visualization of cysts, tumors, obstructive uropathy, and vasculature [9;10]. …”