From the Guidelines
A CT urogram is a critical diagnostic tool used to examine the urinary tract, including the kidneys, ureters, and bladder, with its primary purpose being to detect abnormalities such as kidney stones, tumors, urinary tract obstructions, congenital anomalies, and infections, as supported by the most recent study 1. The procedure involves the use of contrast material injected intravenously, which helps highlight the urinary structures as it filters through the kidneys and collects in the bladder.
- The test takes multiple X-ray images from different angles, which a computer then processes to create detailed cross-sectional views of the urinary system.
- CT urograms are particularly valuable because they provide more detailed information than conventional X-rays and can detect smaller abnormalities that might be missed by other imaging techniques.
- According to a recent review by Mirmomen et al 1, CTU demonstrated a 91% diagnostic accuracy in detecting UCs, making it a highly effective tool for diagnosis and staging.
- Patients should inform their doctor about any allergies to contrast materials, as reactions can occur, and they should also expect to drink plenty of water before the test and possibly take a diuretic to help fill the bladder.
- The entire procedure typically takes 30-60 minutes, and while radiation exposure is involved, the benefits of accurate diagnosis generally outweigh the risks when the test is medically necessary, as noted in the study by Barker et al 1.
- The use of CTU has largely replaced IV urography for evaluating the renal collecting systems and ureters, offering several advantages such as the ability to visualize small masses and distinguish enhancing tumors from nonenhancing calculi or blood clots, as discussed in the study by Jinzaki et al 1.
From the FDA Drug Label
Iodixanol injection is indicated in for: ... (270 mg Iodine/mL and 320 mg Iodine/mL) CT imaging of the head and body. ... (270 mg Iodine/mL and 320 mg Iodine/mL) excretory urography.
A CT urogram is a type of imaging test that uses Computed Tomography (CT) and a contrast agent, such as iodixanol, to visualize the urinary system, including the kidneys, ureters, and bladder. The purpose of a CT urogram is to:
- Evaluate the urinary system for abnormalities, such as kidney stones, tumors, or blockages
- Assist in the diagnosis of conditions affecting the urinary system, such as kidney disease or urinary tract infections
- Provide detailed images of the urinary system to help guide treatment or surgical planning 2 2.
From the Research
Purpose of a CT Urogram
A Computed Tomography (CT) urogram is a medical imaging procedure that serves several purposes, including:
- Imaging of the kidneys, ureters, and bladder to detect and characterize various conditions, such as kidney stones, tumors, and infections 3, 4
- Evaluation of the urinary tract for obstructions, stones, and other abnormalities 4, 5
- Detection and characterization of renal masses and tumors, with the possibility of predicting tumor grading and patient outcomes using radiomics and artificial intelligence applications 3
- Assessment of renal function and detection of complications, such as pyonephrosis, in patients with urinary tract infections 5
Imaging Techniques and Protocols
Different protocols are available for contrast administration and image acquisition in CT urography, with varying strengths and limitations, including:
- Multiphase CT examination with post-contrast excretory phase imaging to evaluate kidney function and urinary tract obstruction 3
- Dual-Energy Computed Tomography for renal stone characterization, synthetic unenhanced phases to reduce radiation dose, and iodine maps for better interpretation of renal masses 3
- Low-dose and ultra-low-dose CT protocols to reduce radiation exposure while maintaining diagnostic accuracy for detection of urinary tract stones 6
Clinical Applications
CT urography has various clinical applications, including: