From the Guidelines
To evaluate hematuria, I recommend starting with a computed tomography (CT) urogram as the preferred imaging study, as it provides detailed images of the entire urinary tract and is effective at identifying urinary tract malignancies, stones, and other structural abnormalities 1. This approach is supported by the most recent guidelines, which emphasize the importance of a thorough evaluation to identify the underlying cause of hematuria, including stones, tumors, infections, or glomerular disease 1.
Key Considerations
- The choice of imaging should be tailored to the patient's clinical presentation, with gross hematuria, older age, smoking history, or occupational exposures warranting more comprehensive evaluation due to higher risk of malignancy 1.
- For patients with contraindications to CT, such as pregnancy or contrast allergy, ultrasound of the kidneys and bladder combined with plain radiography (KUB) offers a reasonable alternative 1.
- Magnetic resonance urography (MRU) can be considered for patients with renal insufficiency or contrast allergies who need detailed imaging 1.
- In cases where bladder pathology is suspected, cystoscopy should complement imaging studies, as it is the gold standard for evaluating bladder cancer 1.
Special Considerations
- For children or young adults with microscopic hematuria and low risk of malignancy, renal ultrasound may be sufficient as an initial study to minimize radiation exposure 1.
- The use of urine cytology or urine-based tumor markers (UBTMs) can assist in cases where the test results may inform the decision regarding the utility of cystoscopy, but renal and bladder ultrasound should still be performed in these cases 1.
Imaging Modalities
- CT urography provides excellent delineation of the excretory urinary tract and is sensitive for urinary stones, but involves ionizing radiation and iodine-based IV contrast 1.
- Renal ultrasonography is relatively less expensive, does not involve ionizing radiation, and has reasonable discrimination for cortical lesions, but image quality is dependent on operator experience and the patient’s body habitus 1.
From the Research
Imaging Studies for Hematuria Evaluation
The following imaging studies can be ordered to evaluate hematuria:
- CT urography: This is a rapidly evolving technique that has high diagnostic accuracy for urothelial cell carcinoma (UCC) and is recommended as the initial imaging test for hematuria in patients at high-risk for UCC 2, 3, 4, 5
- CT scan urography: This includes an unenhanced scan, the nephrographic phase, and the excretory phase, and is useful for evaluating gross hematuria in adults 3
- Unenhanced scans: These are routinely performed to evaluate the basic parameters such as the size, shape, position, and outline of the kidneys and calculus disease 3
- Nephrographic phase: This is useful for detecting renal parenchymal diseases, including masses, and other abdominal organs 3
- Excretory phase: This is useful for detecting urothelial diseases, including upper urothelial cell carcinomas (UCC) 3, 5
Specific Imaging Protocols
- Three-phase CT urography (CTU) is considered the gold standard for evaluating the upper urinary tract in patients with hematuria 5
- However, studies suggest that the CTU protocol can be simplified, as all upper urothelial cell carcinomas were visible on the nephrographic phase 5
Comparison with Other Imaging Techniques
- CT urography has a favorable comparison with other imaging techniques, such as ultrasonography, intravenous urography, and retrograde ureteropyelography 2, 4
- Low-dose CT offers much greater sensitivities for the detection of urinary tract calculi than radiography 4
- Ultrasound alone is insufficient for imaging of hematuria, as it is often difficult to differentiate renal transitional cell carcinoma from other causes of filling defects of the renal collecting system 4