Essentials of Computed Tomography Imaging of Hematuria.

Hematuria is defined usually as the presence of blood in the urine, either on voiding or in a catheterized specimen. Hematuria is broadly divided into microscopic and gross hematuria and may be symptomatic or asymptomatic. The causes of hematuria include a very wide spectrum of conditions. However, here, we have filtered the causes causing gross hematuria, including calculus, trauma, tumors, vascular, and miscellaneous causes. Plain X-rays of the kidney, ureter, and bladder; ultrasound; intravenous urography; computed tomography (CT); magnetic resonance imaging; retrograde ureterography and pyelography (RGP); cystoscopy; and ureteroscopy are techniques that are useful for diagnosis. In the past, one or a combination of several techniques was used to evaluate hematuria but recently, advances in CT urography mean that it can be used alone for this task. This article briefly reviews the common causes of gross hematuria in adults and their evaluation by CT-based urography. Gross hematuria is evaluated well with CT scan urography which includes an unenhanced scan, the nephrographic phase, and the excretory phase. Unenhanced scans are routinely performed to evaluate the basic parameters such as the size, shape, position, and outline of the kidneys and calculus disease, which is the most common cause of hematuria. Renal parenchymal diseases including masses are best visualized in the nephrographic phase along with other abdominal organs. Delayed excretory phases including the kidneys, ureters, and bladder are useful for detecting urothelial diseases. CT urography's protocol permits evaluations of hematuria through a single examination.