Evaluation of solid renal masses by qualitative and quantitative parameters in four phase MDCT with histopathological correlation
Keywords:Four phase MDCT, solid Renal masses, Quantitative measurement
Introduction: Quantitative measurement of the degree of enhancement has not been widely reported for RCC subtypes and fat-poor angiomyolipoma. Previously enhancement in either one of the corticomedullary or nephrographic phases is used for evaluation of renal masses. From the past decade renal mass enhancement is viewed in terms of differences in contrast enhancement and deenhancement patterns over multiple phases on multiphasic MDCT as well as contrast-enhanced MRI to distinguish among RCC subtypes. Most recent studies by Jinzaki et al, sun et al and Vargas et al, Stephanie A. Lee-Felkar et al advanced the concept of multiphasic renal mass attenuation profiles for individual histological subtypes. In our study we follow the current novel approach to the imaging evaluation of renal masses using qualitative and quantitative MDCT feature. Aim/purpose: To characterize the incidentally detected solid renal masses as benign or malignant and differentiating the clear cell RCC from its benign and malignant mimics based on qualitative parameters like lesion contour, calcifications, neovascularity, enhancement and quantitative parameters like mean absolute attenuation, mean relative attenuation, absolute enhancement & absolute de-enhancement in a four-phase MDCT renal mass protocol. Materials and methods: This was an Observational prospective study conducted in 42 patients in the department of Radiodiagnosis at Apollo hospitals, Jubilee hills, Hyderabad referred from the Departments of urology, surgical oncology with a clinical suspicion renal tumors or renal masses which are incidentally detected on ultrasound and referred to CT for further characterizationfor 9 months, from October 2019 to June 2020.Patients of all age groups, both sexes, who were given consent for the study taken and subsequently histopathological findings were followed.Patients with angiomyolipoma with macroscopic fat detectable, predominantly cystic renal masses on CT, Pregnant women and allergic to contrast media are excluded. 128 SLICE PHILIPS INGENUITY CT machine was used for evaluation with parameters of 3mm slice thickness, FOV of 300.00mm, voltage of 120KV, tube current of 300-350mA. Results: This was an observational prospective study was conducted among all the patients who were referred to department of radiodiagnosis for further characterisation and correlate with histopathology as gold standard.The mean age of the study population was 49.2 ± 2.9 yrs. with majority of the patients belongs to 41 – 60 yrs.78.5% of patients in the present study were male and 21.5% were female.85.7% were symptomatic at the time of presentation and the most common symptom was haematuria followed by pain in abdomen.Most common solid renal mass was renal cell carcinoma (54%). Among renal cell carcinomas clear cell RCC is most common histological variant (53%). Among the benign oncocytoma is most common (19%). Among qualitative parameters, neovascularity showed statistically significant P value with high sensitivity, specificity, PPV, NPV & accuracy. All lesions showed maximal attenuation in corticomedullary phase and decreased in subsequent phases except papillary variant of RCC. High mean absolute attenuation in CM phase + Mean relative attenuation of >0% in CM phase + absolute de enhancement >50HU has good sensitivity, specificity in differentiating clear cell RCC from others.Progressive enhancement from corticomedullary to nephrographic phase with highest mean absolute attenuation during nephrographic phase had high sensitivity, specificity & accuracy in differentiating papillary RCC from others.Delayed de enhancement more than 30HU differentiated oncocytoma from chromophobe with high sensitivity and specificity. Conclusion: Qualitative & Quantitative MDCT features enables diagnosis of malignant masses with 100% sensitivity also discriminating CcRCC from its benign and malignant mimics with high sensitivity and specificity.
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Copyright (c) 2022 Esparanto Sudanagunta, Chandra Rakesh Chowdary, Mohd Abdul Rawoof, Karanam Poorna Sasank, Peethamber Lokanandi
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