From the Guidelines
The best ED imaging for hematuria is CTU (CT Urography), as it has been shown to be the most sensitive and specific method for detecting urothelial malignancy and evaluating both nephrogenic and urogenic causes of hematuria. This recommendation is based on the most recent and highest quality study, which found that CTU has a pooled sensitivity of 96% and pooled specificity of 99% for detecting urothelial malignancy 1. The study also showed that CTU is superior to IVU (Intravenous Urography) in terms of sensitivity and specificity, with an accuracy of 99.6% compared to 84.9% for IVU.
Some of the key benefits of CTU include:
- High sensitivity and specificity for detecting urothelial malignancy
- Ability to evaluate both nephrogenic and urogenic causes of hematuria
- Superior accuracy compared to IVU
- Useful for detecting lower tract lesions (bladder) with a specificity and accuracy of 98.8% and 97.2%, respectively
It's worth noting that other imaging modalities, such as ultrasound, may be used in certain situations, such as in pregnant patients or those who cannot undergo CT scanning. However, CTU is generally the preferred imaging modality for hematuria due to its high sensitivity and specificity. The American College of Radiology has also given CTU its highest rating for appropriateness in the work-up of hematuria patients, and notes that the scan must include use of high-resolution imaging during the excretory phase 1.
From the Research
Best ED Imaging for Hematuria
The best imaging modality for evaluating hematuria in the emergency department (ED) is a topic of discussion among radiologists and urologists.
- CT urography is considered the gold standard for evaluating the upper urinary tract in patients with hematuria 2, 3, 4.
- It offers high diagnostic accuracy for urothelial cell carcinoma (UCC) and is preferred over other imaging modalities such as excretory urography and ultrasonography 5, 2.
- However, CT urography may not be suitable for all patients, particularly those with renal impairment or radiation sensitivity, in which case magnetic resonance urography (MRU) may be a better option 3.
- Ultrasound is vital in the initial assessment of hematuria, particularly in low-risk patients and young men <40 years 3.
- Cystoscopy remains the gold standard in the detection of lower urinary tract (bladder) urothelial tumours 3.
CT Urography Protocols
- Most institutions use 3-6 phase CT urography protocols, which are associated with higher radiation doses compared to 2-phase protocols 6.
- The median DLP for CT urography protocols ranges from 1793-3618 mGy.cm, which is significantly higher than the median DLP for urinary stones CT (516 mGy.cm) 6.
- Simplifying the CT urography protocol to a single phase, such as the nephrographic phase, may be possible without compromising diagnostic accuracy 4.
Radiation Dose Considerations
- There are substantial variations in CT urography and routine abdomen-pelvis CT protocols, resulting in massive radiation doses (up to 2945-3618 mGy.cm) 6.
- Few institutions use low-dose CT for urinary stones, and efforts should be made to reduce radiation doses while maintaining diagnostic accuracy 6.