ARRS 2022 Abstracts

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E1349. Peeing Red: Imaging of Hematuria
Authors
  1. Courtney Cave; Henry Ford Hospital
  2. Julie Ruma; Henry Ford Hospital
  3. Amnah Aglan; Henry Ford Hospital
Background
Hematuria is a commonly encountered indication for abdominal imaging and can be an indicator of underlying pathology such as urothelial or renal neoplasm, urolithiasis, or infection. Radiologists must be knowledgeable in the utility of different imaging modalities to facilitate an appropriate workup and diagnosis based on patient demographics and clinical history. This case-based review will explore common and uncommon causes of hematuria, highlighting imaging techniques and key findings to promote accurate diagnosis and guidance of clinical management.

Educational Goals / Teaching Points
The goals of this exhibit are to become familiar with the most common urologic pathologies leading to hematuria including urothelial carcinoma, infection, and urolithiasis; identify classic imaging findings related to hematuria; and understand the utility of different imaging modalities in the setting of hematuria including US, CT, and CT and MR urography.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Hematuria is classified clinically as gross hematuria, visible to the patient or clinician, or microhematuria, detected on urinalysis. Microhematuria is associated with a relatively low risk of malignancy (2.6–4.0%). In the absence of risk factors for malignancy, imaging is not always required for these patients and has a relatively low diagnostic yield. Per ACR appropriateness criteria, a single phase noncontrast CT “may be appropriate,” with all other imaging modalities being “usually not appropriate.” In contrast, gross hematuria is associated with a 30–40% risk of malignancy, and evaluation with CT or MR urogram is usually warranted. Multi-phasic CT urograms include noncontrast, nephrographic, and excretory phases, tailored to detect abnormalities in the kidneys and upper and lower urinary tracts. Urothelial carcinoma is the most common malignancy of the urinary tract and can occur along the renal collecting systems, ureters, or bladder. Urothelial lesions can be difficult to detect on single phase studies, but sensitivity improves on multi-phasic urogram examinations, where lesions can be seen as enhancing soft tissue or filling defects on excretory phase images. Infection: Pyelonephritis and ureteritis are common causes of hematuria in the acute setting. Although these diagnoses are often made by clinical and lab analysis, CT imaging can be used to confirm the diagnosis, identify complications, and rule out alternate etiologies. Noncontrast CT is often normal in pyelonephritis, though contrast-enhanced CT can demonstrate focal areas of hypoenhancement, delayed nephrograms, and altered urothelial enhancement. Up to 80% of patients with renal stones have hematuria. More than 98% of renal stones can be detected on a noncontrast CT and can sometimes be obscured on nephrographic or excretory phase images due to dense surrounding contrast.

Conclusion
Hematuria is a common presenting symptom and may be an indication of an underlying malignancy or other pathology. Understanding the imaging modalities available as well as the common etiologies and their imaging findings is essential for making accurate diagnoses.