Role of MDCT in Radiological evaluation of Renal Masses and its beneficial effects on patient management.

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1 International Journal of advances in health sciences (IJHS) ISSN Vol2, Issue1, 2015, pp Research Article Role of MDCT in Radiological evaluation of Renal Masses and its beneficial effects on patient management. Kapila Akshay, Dhok Avinash and Mitra Kajal Department of Radiodiagnosis NKP Salve Institute of Medical Sciences, Nagpur. [Received-14/01/2015, Accepted-02/02/2015] ABSTRACT OBJECTIVE: To evaluate the efficiency of imaging modalities, viz, x ray, sonography, and MDCT scan in the detection and classification of various cases of renal masses. To list causes of renal masses according to the gender and age groups & to correlate the radiological findings with the operative results/ final outcome. MATERIALS & METHODS: The patients with renal masses is evaluated by X Ray, Ultrasonography (USG) and MDCT scan for a period of 2 years and the findings are correlated with operative findings and FNAC or BIOPSY. This cross sectional study is comprised of 56 patients who were clinically suspected of renal masses & were studied over a period of two years and the findings are correlated with the operative findings and FNAC/BIOPSY. RESULTS: The age group of the patients ranged from 1-80 years. Majority of the lesions were found in age group of years (18 patients). There were 27 male and 29 female patients. RCC (37%) was most common lesion. CONCLUSION: MDCT is one of the most optimal and effective imaging modality for characterization of renal lesions, diagnosis, staging and management of renal neoplasms. Its multiplanar imaging property and high resolution have significant advantage in detection of the renal masses. It can accurately differentiate between solid and cystic lesions, thereby used in characterization of the lesions. Key words: Renal Masses, MDCT, RCC, FNAC, Intravenous Urography, Wilms Tumour. INTRODUCTION Renal lesions are collective term used to describe renal cystic lesion, inflammatory lesion, vascular masses, benign and malignant neoplastic renal masses. Commonest cystic lesion of the kidney is a cortical cyst which includes both simple and complicated cysts; other renal cystic lesions include polycystic renal disease, multicystic dysplastic kidney, multilocular cystic nephroma, renal cysts in hydatid disease, renal cysts associated with some systemic diseases such as

2 Tuberous sclerosis complex(tsc) and von Hippel Lindau Disease(VHL). The most common infection of the kidney is pyelonephritis. It is most often an ascending infection from the bladder. In most instances, the diagnosis of pyelonephritis is established clinically on the basis of flank pain, pyuria (significant numbers of pus cells in the urine), fever and chills. Renal cell carcinoma is the most common tumor of the kidney and represent over 90% of solid renal masses. The remaining masses include adenoma, angiomyolipoma, lymphoma, metastatic tumors, sarcomas and other rare lesions like oncocytoma. Though renal cell carcinoma can actually develop at almost any age, the peak incidence is between the ages of 50 and 60 years. It is more common in men with a ratio of 2:1 compared to women. Environmental factors that have been implicated as potential risk factors include cigarette smoking and exposure to cadmium. Renal tumors occurring in children comprise a spectrum of morphologic subtypes. Wilms tumor (also called nephroblastoma or renal embryoma) is by far the most common form of renal cancer in children. Wilms tumor usually arises in only one of the affected child s kidneys, although approximately 12% of affected children may be diagnosed with Wilms tumor that is multicentric in origin. Approximately 7% of children with Wilms tumor have involvement of both kidneys. Other rarer forms of childhood renal cancers are: clear cell sarcoma of the kidneys, rhabdoid tumor of the kidney, congenital mesoblastic nephroma, multilocular cystic renal tumor and renal cell carcinoma. The wide range of radiological investigations in evaluation of the renal lesions varies from the plain abdominal radiograph, excretory urography, ultrasonography, radionucliede imaging, angiography, CT and MRI. Historically excretory urography has been used as optimal screening test for evaluation of suspected renal mass. Before CT was introduced, ultrasonography, angiography and cystic aspiration were extensively used in diagnosis. Overall diagnostic accuracy of properly performed CT scanning from separating renal cysts from neoplasm is extremely high (95%). Because of unique cross sectional anatomical ability of CT, areas previously difficult if not possible to evaluate by other imaging modalities can now be evaluated. With advent of multi detector CT mass can be studied in very thin sections ( mm) in all the planes (axial, coronal and sagittal) simultaneously and accurate location of the mass can be precisely identified. Evaluation of renal mass by CT involves consideration of several features including mass size, shape, location, number, density (attenuation value), degree of homogenicity, contrast enhancement and relationship with other organs and extension of the mass to the perinephric structures, infiltration into the adjacent structures and tumoral thrombosis of the renal vein and inferior vena cava (IVC) are well delineated. CT scanning is also appropriate modality for detecting blood borne metastases to the liver, lung and bone. The lungs, liver, lumbar spine and pelvis can be studied at the same time as the renal examination. In general, multi detector CT serves as a single step investigation for suspected renal masses. It also provides most valuable amount of information with regard to the size, and location of the lesion, perinephric spread, venous involvement, degree of lymphadenopathy, adjacent organ infiltration and distant blood borne metastases to liver, lung and bones. MATERIALS & METHODS: The present study Importance of Radiological Evaluation in Renal masses and Its Beneficial Effects on Patient Management is carried out on: X-Ray (GE Tejas, 630 ma) USG - MyLab 50 (Esaote), My Lab 40, (with convex and linear probe) MDCT - 16 Slice Toshiba, Activion The Ultrasonography, X Ray and CT scans of around 56 consecutive patients presenting to the out patients or emergency department with renal Dhok Avinash, et al. 57

3 masses was examined. After clinical evaluation of the patient, Helical CT of both the abdomen and pelvis was performed after oral and intravenous contrast material administration. Results were correlated with surgical findings and FNAC or BIOPSY. The patients with renal masses were evaluated by X Ray, Ultrasonography (USG) and C.T scan for a period of 2 years and the findings were correlated to the operative findings and FNAC or BIOPSY. Following Patients were included: 1. Patients with pain in lumbar region and renal angle. 2. Patients who are diagnosed as having any lesion during USG examination. 3. The signs and symptoms suggestive of renal masses like: The palpable abnormalities like lump, tenderness. a) Hematuria b) Fever c) Weight loss d) Hypertension e) Hypercalcemia, night sweats, malaise, and a varicocele, usually left sided, due to obstruction of the testicular vein (2% of males). After clinical evaluation & patient selection, X ray, Sonography and CT scan of the patient was performed and the patient is followed up until the outcome is achieved in terms of: 1. Patient getting normal with conservative management or having a chronic course which will also include correlating the radiological findings with the operative findings. 2. Patient required immediate surgery. 3. Patient required elective surgery. Following patients were excluded from the study: 1. Previously treated patient with conservative or operative management. 2. Patients who opt for getting further line of management (diagnostic/conservative/surgical) outside our institute. 3. Trauma patients. 4. Pregnant females. 5. Patients with contraindications to intravenous administration to contrast medium. OUTCOME MEASURES: A complete radiological examination usually provides information about the possible origin of the pain and hematuria and any other symptom. The outcome can be measured as follows: 1. By assessing the percentage to which x-ray, ultrasonography and CT scan can localize the site of lesion in lumbar region. 2. By correlating the frequency of various high risk groups as stated with the occurrence of cancers. 3. By correlating the radiological findings with the operative results. 4. By determining the sensitivity and specificity of ultrasound imaging and CT scan in distinguishing various flank pain, hematuria and related cases. STATISTICAL METHODS The data on demographic parameters, clinical symptoms and biochemical parameters was obtained on 56 patients enrolled in the study. The frequency distributions were obtained for each parameter along with percentages. Also, the data on X-ray, USG and CT findings were obtained for each patient. Association of X-ray calcification and CT findings was obtained in terms of contingency table. Further, intravenous urography findings were correlated with CT findings. Frequency distribution of patients from each diagnostic category was obtained according to gender and side. Association of USG findings with CT findings was studied through contingency table. The size of lesion, location and enhancement were also studied according to CT findings. The X-ray and USG findings were also correlated with pathological findings. The Dhok Avinash, et al. 58

4 sensitivity, specificity, Positive predictive value (PPV) and Negative predictive value (NPV) of USG for various diagnosis was obtained with reference to CT findings. RESULTS: A total of 56 patients, suspected clinically of renal masses who underwent X-ray, Intravenous Urography, Ultrasonography and CT scan abdomen study during period of two years. The mean age of the study sample was years with range of 1-80 years. The number female patients were marginally more (52%) as compared to male patients (48%). Pain in abdomen, hematuria and palpable mass were most frequent presenting complaints. Renal cell carcinoma was most common lesion. Contrast enhanced abdominal CT scan using MDCT, is useful in accurate diagnosis and staging of renal masses. The distribution of patients as per CT findings and Pathological findings are: All 21 RCC cases that were diagnosed on MDCT pathologically also showed RCC. All the 7 cases of Wilms tumor by Pathology showed the same findings on CT. Two Oncocytoma cases which were diagnosed as central non enhancing scar on MDCT also proved to be Oncocytoma on Pathology. Rest of the lesions like Angiomyolipoma, Abscess, Xanthogranulomatous pyelonephritis, ADPKD and Cysts were diagnosed on MDCT. DISCUSSION: With the explosion of technologies in diagnostic Radiology, more and more small, asymptomatic renal lesions are being detected thereby increasing cure rate and patient survival. Many asymptomatic renal cell carcinomas are now being discovered incidentally during abdominal sonography and CT done for reasons other than suspected renal tumor. Intravenous urography was and still remains the primary screening test for all patients who present with urinary tract symptoms such as haematuria. It is well known, however, that small renal tumors especially those which are exophytic and arise from anterior or posterior renal surfaces, may not be detected on intravenous urography.(kass et al 1983; DEMOS et al,1985) 1,2. If there is a strong clinical suspicion of a renal tumor, further evaluation is essential even with a normal intravenous urogram (WARSHAUER et al, 1988) 3. Also, since intravenous urogram is known to be very reliable in differentiating between benign and malignant renal masses, It is mandatory to follow the urographic finding of any renal mass with a more definite radiological study. This is necessary for both characterization of the mass and in determining the extent if the mass has features suggesting a malignancy. In the present study, 56 cases of renal masses were investigated Radiologically using modalities like X-ray, Ultrasonography and MDCT. Initially as a radiological investigation X-ray was done to rule out calcification. Out of 7 cases of Abscess, calcification was present in only 1 case. All the ADPKD cases showed absence of calcification. Also, all the Angiomyolipoma cases showed absence of calcification. Out of two cases of Cyst, one had calcification. All the Oncocytoma and Xanthogranulomatous Pyelonephritis cases showed absence of calcification. Only one out of 21 RCC cases showed calcification. Only one case of Wilms tumor showed calcification. Intravenous Urogragraphy to study the calyceal abnormalities were done. Out of 7 patients diagnosed with Abscess, 3 patients had Nonvisualization of involved kidney and 2 each had Distortion & displacement of calyces and Poor excretion. Amongst those diagnosed with ADPKD, 3 each had poor excretion and Stretching and splaying of calyces. Out of 5 patients of Angiomyolipoma, 3 patients had Stretching and splaying of calyces, while one each had delayed excretion and poor excretion. Out of two patients with Cyst, one each had Non-visualization of involved kidney and Poor excretion. There were 3 patients of Oncocytoma, 2 had Poor excretion, while one had Non-visualization of involved Dhok Avinash, et al. 59

5 kidney. Out of 5 Xanthogranulomatous Pyelonephritis patients, 2 each had Distortion & displacement of calyces and Poor excretion. Out of 21 RCC patients, 4 each had Non-visualization of involved kidney and Poor excretion, while 11 had Distortion & displacement of calyces and 2 had Delayed excretion. There were 7 cases of Wilms tumor out of which 3 each had Delayed excretion and Poor excretion. MDCT is an effective and excellent modality for detecting all renal lesions. Studies subsequent to intravenous contrast administration are helpful in characterizing renal neoplasms. In the present scenario it is an excellent modality for answering most important questions prior to the surgical intervention. It is considered as the imaging modality of choice for characterization and staging of disease. In this study of 56 patients, who were clinically suspected of renal masses were included. The age group of the subjects ranged from 1-80 years. Majority of the lesions were found in age group of comprising of 18 patients in the age group of 61-70, followed by years age group comprising of 10 patients. There were 27 males and 29 females patients. In the present study, all the patients had undergone X-ray, Intravenous urography and ultrasound examination prior to MDCT examination. Renal cell carcinoma was most common lesion and it was 37.5% of all renal lesions. RCC was most common in years age group (52.3%). Youngest patients were of 20 years and eldest was 72 years. With regard to sex distribution, there were 27 (48.2%) males and 29 (51.7%) females. These epidemiological features were not consistent with those observed by Peterson R O 4 which showed female predominance. Hematuria was present in 12 patients with RCC (57.1%) patients, flank pain in 10 patients (47.6 %). There were 14 (66.6 %) RCC cases noted in right kidney, while 7 (33.3 %) in the left kidney. There were 2 tumors with size more than 8.0 cms. All the tumors showed heterogeneous contrast enhancement. This attributed to necrosis and hemorrhage with enlarged tumors. Calcification was found in 1 case with RCC, that was non peripheral, central type with nodular or stippled pattern of calcification. Peripheral calcification was not observed in any of the cases. These findings were in agreement with 5 findings of Weyman et al who observed calcification in 8-18 % cases of RCC with 90% of them showing central calcification.3 patients had ipsilateral renal vein involvement, where as 2 had IVC involvement i.e. thrombosis of renal vein and IVC. Detection of the level of involvement significantly alters the surgical approach. Lymphadenopathy was noted in 14.2% of patients. Distant metastases to lungs and liver were seen in 19 % of patients. Tumor staging for RCC was done according to TNM staging. There were 10 (47.6%) cases with stage IV and 11 (52.3%) with stage I. Higher incidence of stage I disease in the present study is seen. All patients showed renal clear cell carcinoma on histopathology. All the patients had prior USG scans in which only 7 (33.3%) reported the probability of renal tumor. Although it may occur in childhood 6, it is 7. common in the fifth to seventh decade Yamashita et al 8 analyzed 27 cystic renal cell carcinomas in 23 patients radiologically and histologically. Next commonest lesion found in the present study was Wilms tumor. It accounted for 12.5% cases. Age of the patient ranged from 1-3 years, 2 years being the mean age. Male to female ratio was 2:5. Three patients (42.8%) presented with mass per abdomen. These clinical and epidemiological features corroborate with those stated by Peter S 9 In 71.4% of patients right kidney was involved, while 14.3% had left kidney involvement and bilateral kidney involvement was noted in 14.3%. All the tumors showed heterogeneous enhancement with necrotic areas in 28.5%. 14.3% of the cases showed calcification. 28.6% the cases had thrombosis of renal vein and IVC. However right atrial thrombus was noted in one patient.all Dhok Avinash, et al. 60

6 the patients had prior USG scans before under going MDCT examination.57 % of these cases were reported as probable Wilms tumor.all the cases were histopathologically proved as Wilms tumor. Tumor was in stage II in 3 (42.8%) patients, stage III in 3 (42.8%) patients, stage V in 1 (14.3%) patient. Tumors that arise from the peripheral cortex may grow in an exophytic manner with most of the tumor content outside the kidney 10. On contrast study, the tumors appear less dense than normal renal parenchyma and often exhibit extensive necrotic areas 11. Renal abscess was noted in 12.5 % of the patients. The male to female ratio was 3:4. In 57.15% of the cases involvement on left side and 42.85% patients had right renal involvement. Age of the patients ranged from years. 43% of the patients had pain in abdomen, hematuria was noted in 3 i.e. 43% of the cases. Abscesses in 3 (43%) patients showed heterogeneous enhancement. There was extension of the abscess to Gerota s fascia and perinephric region in 3 (43%) patients a finding proved by Soulen M C et al. 12 Prior USG examination was proved to be wrong in 3 (43%) of the cases. 10.7% of the patients had autosomal dominant polycystic kidney disease. 4 were male and 2 female patients. Age range of the patients was years. All the patients presented with pain abdomen. Multiple hepatic cysts were noted in 4 (66%) cases. None of the patients had cysts in pancreas and spleen. 8.9 % of the cases in the present study were comprised of Xanthogranulomatous pyelonephritis. Male to female ratio was 2:3. 40% of the patients had bilateral kidney involvement. 3 out of 5 the patients (60%) presented with fever and 4 patients with hematuria. All the 5 patients of Xanthogranulomatous pyelonephritis showed heterogenous enhancement, these findings consistent with Gold R P et al. 13 All patients had prior USG. All the patients on USG were reported as Xanthogranulomatous pyelonephritis Angiomyolipoma was noted in 8.9% of the cases. Male to female ratio was 3:2.60% of the patients had bilateral kidney involvement. Only 1 patient had clinical symptoms such as pain in abdomen. MDCT showed lesions with fat containing within them. On contrast there was heterogeneous enhancement. None of these cases were associated with systemic disorders. 3 (5.3%) patients were diagnosed of oncocytoma. All of the patients were female,only 1 patient presented with pain in abdomen. There was heterogeneous enhancement in two cases, third case showed no enhancement. However both the cases showed centrally located enhancing scar on delayed scans. One patient had prior USG which mentioned as probable RCC arising from left kidney. Cysts were noted in 2 patients. There were few simple cortical cysts inbilateral kidneys in one case.other case had complex cyst in the interpolar region of right kidney. The patients with Renal cell carcinoma (21 patients), wilms tumour (7 patients) and ADPKD (6 patients) had undergone elective surgery. Patients with Xanthogranulomatous pyelonephritis (5 patients) and abscess (7 patients) had undergone conservative management with antibiotics. Benign lesions like Onycocytoma (3 patients) and Angiomyolipoma (5 patients) were kept under conservative management. CONCLUSION: MDCT is one of the most optimal and effective imaging modality for characterization of renal masses, diagnosis, staging and management of renal neoplasms. Its multiplanar imaging property and high resolution have significant advantage in detection of the renal lesions. It can accurately differentiate between benign and malignant lesions, solid and cystic lesions, there by aiding in characterization of the lesions. Features of lesions such as location, size, calcification, cystic areas, hemorrhage, fat and extent to perinephric regions can be accurately assessed. Dhok Avinash, et al. 61

Renal cell carcinoma is the most common malignant tumour in old age where as wilms REFERENCES: 1. Kass DA, Hricak H, Davidson A J. Renal malignancies with normal excretory urograms.

7 Renal cell carcinoma is the most common malignant tumour in old age where as wilms REFERENCES: 1. Kass DA, Hricak H, Davidson A J. Renal malignancies with normal excretory urograms. Am J Roentgenol 1983; 141: Demos TC, Schiffer M, Love L et al. Normal excretory urograms in patients with primary kidney neoplasms. Urol Radiol 1985; 7: Warshauer D.M., McCarthy S.M, Street L et al. Detection of renal masses: sensitivities and specificities of Excretory urography / Linear Tomography, US and CT. Radiology 1988 ; 169 : 363: Peterson R 0., "Urologic pathology", Philadelphia., Lippincott, Weyman R J, McClennan B L, Lee J T et al., 1982, "CT of calcified renal masses", AJR, 138 : Levine C, Levine E., 1990, "Small pediatric renal neoplasms detected by CT", J. Comput. Assist. Tomogr, 14 : Levine E., Clinical urography : an atlas and textbook of Urological imaging - Malignant tumour is the most common malignant tumour in the early childhood. renal parenchymal tumors in adults, Philadelphia: WB Saunders, Yamashita Y, Miyazaki, Watanabe et al., 1994,"Cystic renal cell carcinoma: Imaging findings with pathological correlation", Acta Radiologica, 35: Peter Strouse, 1996, "Paediatric renal neoplasms: Advances in Uroradiology - II", RCNA, 34 (6) : Fishman E K et al., 1983, "The CT appearance of Wilm's tumor", J.comput. Assist. Tomoqr, 7: Reiman T A H, Siegel M J, Shackelford G D., 1986, "Wilm's tumor in children: abdominal CT and US evaluation", Radiology, 160 : Soulen M C et al., 1989, "Bacterial renal infection: role of CT", Radiology, 171 : Gold RP, McClennan BL, Kenney PJ, Breatnach ES, Stanley RJ, Lebowitz Ri. Acute infections of the renal parenchyma. In: Pollack HM. ed.clinicalurography. Philadelphia, Pa: Saunders, 1990; FIGURES AND TABLES: Figure 1: MDCT post contrast coronal image showing RCC in the mid and lower pole of Left kidney. Dhok Avinash, et al. 62

Figure 2: Contrast enhanced axial MDCT image showing Wilms tumor in Left Kidney causing mass effect on adjacent structures. TABLE: 1-Distribution of patients as per MDCT and pathology findings.

8 Figure 2: Contrast enhanced axial MDCT image showing Wilms tumor in Left Kidney causing mass effect on adjacent structures. TABLE: 1-Distribution of patients as per MDCT and pathology findings. TABLE: 2 CT vs USG diagnosis CT findings Oncocytoma (n=2) RCC (n=21) Parameters Wilms tumor (n=7) Abscess (n=7) ADPKD (n=6) Angiomyolipoma (n=5) Cyst (n=2) Oncocytoma (n=3) Xanthogranulomatous Pyelonephritis (n=5) RCC (n=21) Wilms tumor (n=7) TP FN FP TN Sensitivity (%) Specificity (%) PPV (%) NPV (%) Abscess ADPKD Angiomyolipoma Xanthogranulomatous. Pyelonephritis RCC Wilm s tumor TP: True Positive, TN: True Negative, FP: False Positive, FN: False Negative. Dhok Avinash, et al. 63

Pediatric Retroperitoneal Masses Radiologic-Pathologic Correlation

Acta Radiológica Portuguesa, Vol.XVIII, nº 70, pág. 61-70, Abr.-Jun., 2006 Pediatric Retroperitoneal Masses Radiologic-Pathologic Correlation Marilyn J. Siegel Mallinckrodt Institute of Radiology, Washington