 into the retroperitoneum CT evaluation of renal tumors. Instruction, reduction of malignant renal masses and their differentiation from their benign counterparts is extremely important, especially when these masses are small. Despite recent advances, most in adenocarcinomas are relatively unresponsive to chemotherapy and radiation therapy. Surgery of low stage lesions remains the only hope for long-term survival and cure. CT is the most sensitive imaging modality for detection of renal masses. Objectives of the study, detection and characterization of renal masses which are considered indeterminate or malignant or ultrasound therapy. Materials and methods study was done on patients with suspicion of renal tumors who were referred to the department of radio diagnosis. Patients were evaluated through the computer tomography using the G-revolution, the retuselase scanner. It was obtained with a single breath hold time from the level of diaphragm to the level of iliac crest. Results. In our study, total of 50 cases were taken. 32 were males, 18 were females, 43 were malignant cases and 7 were benign cases. Out of which, renal cell carcinoma was the majority which included 21 cases, accounted for 62% of all renal masses and 72% of malignant renal masses. Transitional carcinoma or 2 in number, ILIMS tumor 7, endostasis 3, cysts 3, abscess 2, multilocular cystic nephroma 1, oncocytoma 1. Coming to discussion. This is the normal, different phases of normal renal contrast enhancement on MDCT. This is a non-contrast enhancement. This is the contracortico-modulary phase enhancement. This is the nephrogenic phase enhancement and this is the excretory phase enhancement. Coming to renal cysts, it is the most common renal mass in the adult and simple renal cysts arise from the cortex. Simple cysts may become complicated as a result of hemorrhage, infection or other processes that thicken some or the entire wall and may increase the alternation of the contents. According to Bosnia, it has been classified into four types. Bosnia type 1, 2, 3, 4. Type 1 is uniform lower attenuation and non-enhancing wall. Type 2 is cyst with uniform high attenuation and no enhancement. Type 3 is cyst with thin enhancing separations. Type 4 is cyst with definite solid enhancing component. Coming to renal cell carcinoma. Pathologically, adenocarcinoma, it is the most common primary renal malignancy in adults occur most commonly in males. It is sporadic but can be associated with one-people lindar syndrome. The risk factors include topical smoking, exposure to petroleum products or asbestos. RCC is the most common, most commonly and incidentally detected renal mass. But it may present with symptoms such as pain, hematuria, weight loss or abdominal distension. Histologically, it is divided into six types. Clear cell type, which is the most common type. Multirocular type, papillary type, chromophobic type, collecting duct and renal medullary type. Props and staging of renal carcinoma include stage 1, which is confined to kidney. Stage 2, involvement of perinephric pattern limited to zero-dose fascia. Stage 3A, renal vein environment. 3B, nodal environment. Stage 4 is further divided into 4A with direct intervention of structures. 4B is distant metastasis. This is renal cell carcinoma. NECT shows the soft tissue exophytic mass in the left kidney. Lesion shows enhancement on contrast administration. This is another case which shows areas of calcification in a renal cell carcinoma case. This is a case of stage 3 renal cell carcinoma. NECT shows soft tissue mass in the right kidney. With pockets of air in the posterior perineal space. The lesion shows enhancement and infiltration into the second part of the odenoma and the right source muscle. This is stage 4 renal cell carcinoma with hypervascular metastasis in the right lobe of liver and renal cell carcinoma with canon bond primary metastasis. Pulmonary metastasis. Transitional carcinoma. The second most common renal renal neoplasm. It is seen in urinary bladder followed by ureter and renal pelvis. This factors include NSAID abuse, tobacco use and occupational exposure. Patients presents with hematuria, pain and weight loss. Most common 3D appearances. It is a small hypodense lesion. The amount of enhancement is less than that of surrounding renal parankaima. Therefore it appears hypodense compared to the kidney. This is a enhancing soft tissue mass filling the entire right follicle is a system causing proximal hydronephrosis. It is the most common primary malignant tumor of the childhood. Renal tumor of the childhood. It is seen in children age 3 to 4 years. In some cases it is associated with W-A-G-R syndrome, Drash syndrome or Beckwith-Weidman syndrome. They present most frequently with palpable abdominal mass less often with abdominal pain or gross hematuria. Approximately 10% of metastatic disease are the presentation. Metastasis are characteristic to the lungs less frequently to the liver. This is a case of Wilhelm's tumor unenhanced CT scan. It shows a hydrogenous soft tissue mass almost replacing the right kidney with the discrete areas of calcification noted within. This is another case of Wilhelm's tumor stage 3 which shows involvement of IVC as a non-enhancing defect and invasion of renal vein. Metastasis, renal metastasis are present in approximately 10 to 20% of patients. It is the most common primary are lung, colon, breast carcinoma, melanoma and reproductive organ malignancies such as testicular or ovarian carcinoma. This is a case of bilateral renal metastasis. CT shows bilateral renal metastasis from colonic carcinoma which did not show any enhancement. This is a case of lung carcinoma metastasis to the left kidney which shows a unifocal soft tissue dilution which shows a heterogeneous enhancement. Renal oncocytoma is a benign tumor. It appears as a solid enhancing mass with characteristics like those of RCC. In fact, the appearance of typical renal oncocytoma cannot be differentiated from RCC. It is more common in men whether asymptomatic but it is a pain or a mass. This is a case of renal oncocytoma. NECT shows a soft tissue exophantic mass with high-potency areas. CCT shows enhancing mass with non-enhancing high-potency area representing central scar. Angiomyolipoma are commonly isolated sporadic tumors or associated with tumor tuberous sclerosis. Sporadic KMLs without tuberous sclerosis are commonly distributed in females associated with neurofibrotosis 1, VHL or ADPKD. CCT is generally a most accurate method because the presence of gross fat is characteristic of this lesion. The ROI of the lesion is typically less than 10 H. This is a case of angiomyolipoma high-potency lesion less minus 20 HU involving the context of red kidney showing minimally enhancement. Renal abscess is a collection of infective fluid in the kidney. It can affect any age, any gender, risk factors being diabetes milliliters in the galliculate. Most common signs are fever, plank pain, abdominal pain, gist, dysuria. CCT is the most accurate method and abscess appears as a well-defined mass of low attenuation with thick irregular wall or pseudo-capsule. It can be better visualized on contrasting and scans. If there is gas within the low attenuation mass then it strongly suggests abscess formation. CCT of renal abscess, in a CCT shows isodensilation in the mid pole of red kidney with thickening of collecting system. Lesion shows peripheral enhancement with thickened enhancing collecting system. The adjacent cortex shows decreased enhancement attenuation due to edema. Coming to last one, multi-locular cystic infromar. It is a distinct renal tumor of uncertain origin. It is a bulky, well-encapsulated, non-infected with multiple non-communicating fluid filled loctoles. It is predominantly evaluated in child because of a painless mass of the upper abdomen. It presents as an abdominal pain and hematuria. Hematuria is often also with herniation of tumor into the renal pelvis. Ceptide is usually thin with no enhancement. Usually the lesion is a thick capsule. Ceptile calcification is seen in about 10% of the cases. CT appearance, any CT shows a large multi-subdater cystic lesion with thick calcified wall in the right kidney with no enhancement on contrast study. Coronal reformatory demand shows clearly well-maintained head plane around the lesion. This is a case of multi-locular cystic infromar. Summary, the study was done to show that the majority of renal masses were better detected, characterised and staged on multi-basic helical CT than other imaging modalities like intravenous pyrography, ultrasound or MRI. Thank you.