What is a CT Urogram and What Can It Identify?
A CT urogram is a specialized imaging test that provides detailed pictures of your entire urinary system, including your kidneys, ureters, and bladder using X-rays and intravenous contrast to detect various urinary tract conditions and abnormalities. 1
How a CT Urogram Works
A CT urogram involves several phases of imaging:
- Unenhanced phase: Initial images without contrast
- Nephrographic phase: Images after contrast has enhanced the kidneys
- Excretory phase: Images taken about 5 minutes after contrast injection when the contrast has filled the collecting system 1, 2
The excretory phase is particularly important as it allows visualization of the contrast as it flows through and fills your urinary system, highlighting any abnormalities that might otherwise be missed 2.
What a CT Urogram Can Identify
Urinary Tract Cancers
Urinary Stones and Obstructions
- Kidney stones (including CT-radiolucent stones that might be missed on regular CT)
- Ureteral stones
- Urinary tract obstructions 2, 5
Anatomical Abnormalities
- Congenital anomalies of the kidneys and ureters
- Urethral or bladder diverticula
- Abnormal connections between organs 3, 2
Inflammatory Conditions
- Signs of infection
- Chronic inflammatory changes
- Papillary necrosis 2
Trauma-Related Injuries
- Kidney injuries
- Ureteral injuries
- Bladder ruptures or tears 3
Other Conditions
- Perinephric collections or fluid
- Filling defects in the urinary tract
- Focal wall thickening of the urinary tract 3, 2
Advantages Over Other Imaging Tests
CT urography has largely replaced older tests like intravenous urography (IVU) because:
- It provides more comprehensive information in one examination 6
- It can detect small lesions that might be missed by ultrasound or IVU 1, 4
- It allows visualization of the entire urinary tract from kidneys to bladder 3
- It can identify problems both inside and outside the urinary tract 5
What to Expect During the Test
- You will lie on a table that moves through a donut-shaped scanner
- You will receive intravenous contrast (dye) through an IV
- Multiple sets of images will be taken at different times
- The entire procedure typically takes 30-45 minutes
- You may be asked to hold your breath briefly during scanning
Important Considerations
- The test involves exposure to radiation
- You will need to have normal kidney function to safely receive the contrast
- You should inform your doctor if you have allergies to contrast materials
- You may need to drink extra water after the test to help flush the contrast from your system 1
CT urography is particularly recommended for patients with high-risk factors such as hematuria (blood in urine), recurrent urinary tract infections, or suspected urinary tract cancers 1, 4.