الفهرس 
Anatomy of the Urinary SystemOnly 14 pages are availabe for public view
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Abstract
Haematuria is defined as the presence of blood in urine. It has a wide range of causes, including calculi, neoplasms, infections, trauma, drug toxicity, coagulopathy, and varices. Assessment of urologic malignancy is the most important cause for evaluation of patients with haematuria.
Evaluation of patients with haematuria frequently requires several imaging modalities including intravenous urography ( IVU ), ultrasonography(US), computed tomography ( CT), magnetic resonance imaging (MRI), retrograde uretrography and pyelography, cystoscopy and uretroscopy.
Multi-slice CT urography performed with a combination of unenhanced, nephrographic-phase, and excretory-phase imaging can demonstrate a wide spectrum of disease in these patients with a single study. Unenhanced imaging provides optimal detection of calculi which is a common cause of haematuria. In addition, the combination of unenhanced and nephrographic-phase imaging provides outstanding evaluation of renal masses. Findings at excretory ¬phase imaging mimic IVU findings and allow excellent evaluation of the collecting systems and ureters. Bladder disease, a common cause of haematuria, is often well seen on unenhanced or excretory-phase images, although cystoscopy may still be necessary.
Multi-slice CT urography (MSCTU) offers several advantages for imaging of the urinary system: single breath-hold coverage of the entire urinary tract with absence of respiratory mis-registration, rapid imaging with optimum contrast medium opacification and reduced partial- volume effect as appropriate slices can be selected from the volumetric data. In addition, acquisition of multiple thin overlapping slices provides excellent two-dimensional (2D) and three-dimensional (3D) reformations, and facilitates virtual cystoscopy. These advantages have established MSCTU as a compelling alternative to excretory urography (EU) and ultrasonography (US) in the evaluation of the patient with haematuria.
One of the main advantages of MSCTU in the evaluation of the urinary system for causes of haematuria is its ability to display the entire urinary tract, including renal parenchyma, pelvicalyceal systems, ureters and the bladder using a single imaging test. The alternative imaging studies including ultrasonography, excretory urography, and nuclear medicine alone do not offer equivalent coverage.
Although magnetic resonance urography (MRU) is the only other alternative study, which can image all the anatomic components of the urinary tract in a single test, its main disadvantages which have hindered its widespread usage in the evaluation of the urinary tract, is its inability to detect urinary tract calcifications, calculi and air; limited availability in comparison to MSCTU; and limited experience in interpretation of images.