Renal imaging

The renal tract is mainly investigated for abnormal renal function and to identify causes of renal colic and haematuria. Increasing use of ultrasound and computed tomography have limited the role of plain radiographs. However, they are still used in the initial assessment of abdominal colic to evaluate potential renal or bowel abnormalities. Intravenous urograms are radiological examinations of the urinary tract performed following the intravenous injection of iodinated contrast. They are the classical means by which to assess the kidneys and ureters. Ultrasound is often the first imaging modality used to interrogate and follow up renal abnormalities. Renal calculi and other focal renal lesions are readily visualized. Computerized tomography (CT) can be useful to evaluate renal masses and determine the site of ureteric obstruction by calculi. Magnetic resonance scans (MRI) are primarily used to assess the renal arteries in patients with suspected renal artery stenosis. CT and MRI can provide images of exceptional detail and resolution, beyond the means of other modalities. In addition, images can be obtained in multiple planes. Radionuclide scans can be helpful in the evaluation of renal tract obstruction. They provide a functional assessment of the renal tract.