Magnetic resonance imaging in acute and chronic kidney diseases: present status.

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.