From the Guidelines
For hematuria without bacteria, CT urography is the best imaging modality. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of thorough imaging in patients with hematuria to rule out malignancy and other potential causes of bleeding 1. CT urography is a specialized CT scan that uses contrast material to provide detailed images of the entire urinary tract, allowing visualization of the kidneys, ureters, bladder, and urethra. The procedure typically involves three phases: non-contrast, nephrographic (showing kidney tissue), and excretory (showing contrast in the collecting system).
Some key points to consider when evaluating hematuria include:
- The patient's age, with those over 40 years old being at greater risk for malignancy 1
- Risk factors for malignancy, such as smoking, occupational exposure to chemicals, and history of urologic disease 1
- Radiation exposure concerns, with CT urography being a valuable tool despite these concerns due to its high sensitivity and specificity 1
- The potential for cystoscopy to be used alongside imaging to directly visualize the bladder lining, particularly in patients with a high risk of bladder cancer 1
Alternative imaging modalities, such as ultrasound and MR urography, may be used in certain situations, such as in pregnant patients or those who cannot receive contrast. However, CT urography remains the gold standard for evaluating hematuria due to its high diagnostic accuracy and ability to detect a wide range of potential causes of bleeding 1.
From the Research
Imaging Options for Hematuria
- CT urography is a recommended initial imaging test for hematuria in patients at high-risk for urothelial cell carcinoma (UCC) 2
- Multiphasic computed tomography urography is best for evaluating the upper urinary tract, identifying hydronephrosis, urinary calculi, and renal and ureteral lesions 3
- Cystoscopy is used to evaluate the cause of hematuria in the bladder, while ultrasonography may be used as an initial screening tool, especially for patients with lower risk of malignancy 4
Diagnostic Approach
- A comprehensive history, focused physical examination, laboratory studies, image-based assessment of the upper urinary tract, and cystoscopic evaluation of the lower urinary system are necessary for investigating the cause of hematuria 5
- The American Urological Association has published guidelines for the management of asymptomatic microscopic hematuria, which include the use of CT urography and cystoscopy for evaluation 3
Specific Considerations
- In patients with asymptomatic microscopic hematuria, the risk of urologic malignancy is increased in men, persons older than 35 years, and persons with a history of smoking 3
- Dysmorphic red blood cells, cellular casts, proteinuria, elevated creatinine levels, or hypertension in the presence of microscopic hematuria should prompt concurrent nephrologic and urologic referral 3