الفهرس 
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Abstract
RCC is the most common type of kidney neoplasm, responsible for approximately 80% of cases originates in the lining of the proximal renal tubule.
There are several subtypes of RCC: Clear cell renal cell carcinoma, Papillary renal cell carcinoma, Chromo-phobe renal cell carcinoma, Collecting duct renal cell carcinoma, Unclassified renal cell carcinoma.
Prognosis for RCC varies considerably depending on the disease stage at diagnosis. Staging systems formalize the way in which the extent of RCC is being described and classified. Primary staging of RCC aims at evaluating surgical options. The tumor, nodes, and metastasis (TNM) classification is the preferred system for RCC staging, it separated tumors with venous involvement from those with lymphatic invasion, quantified each, and defined the anatomic extent of disease more explicitly .Another advantage of the TNM system is that it has facilitated comparison of clinical and pathologic data from various centers across the globe.
Modern cross-sectional imaging methods, such as multidetector-row computed tomography (MDCT) perform highly in T-staging of local tumor extent, N-staging of lymph nodes and M-staging of distant metastasis.
Multi-detector computed tomography has become the imaging modality of choice for evaluation of the kidneys and urinary tract neoplasm.
The most commonly used MDCT protocol comprises three phases that preceded by a non contrast-enhanced (precontrast) series of images through the kidney. Non-contrast Ct scans are obtained to locate the kidneys, evaluate urolithiasis, calcified renal masses or urinary bladder masses and obtain baseline density measurements of renal masses.
Followed by the contrast-enhanced three phases : Arterial-phase imaging: performed to evaluate the arterial anatomy, it is a short phase that occurs after a delay time of approximately 15 to 25 seconds. The nephrographic (corticomedullary or venous) phase: performed to evaluate the venous anatomy, begins approximately 30 to 40 seconds and continues for approximately 60 seconds is optimal for the detection of focal masses arising in the cortex or medulla and for evaluation of the renal parenchyma. The delayed phase (the excretory or urographic phase): used to evaluate renal collecting system and ureters, begins 3-5 minutes after the start of contrast medium injection.
Unlike the renal parenchyma, renal masses do not contain functioning renal nephrons. Vascular tumors display maximum enhancement in the arterial phase (AP); however, in the delayed phases like venous phase (VP) and excretory phase (EP), almost all renal masses have lower attenuation than the homogeneously enhancing surrounding normal renal tissue.
Many MDCT protocols include multiplanar reformatted images or three-dimensional (3D) reconstructions. Due to improvements in software, image reformatting is now easily performed, requiring minimal effort and time. Four main 3-D visualization techniques currently are used on clinical 3-D workstations: Multiplanar reformation (MPR), Maximum intensity projections (MIP), Shaded surface displays (SSD), and a Volume-rendering technique (VRT).
These techniques have a major role in staging of RCC by detection of tumor location and its extent to the perinephric fat or the nearby structures with high performance and accuracy.