Differentiation of Renal Oncocytoma and Renal Clear Cell Carcinoma Using Relative CT Enhancement Ratio

Abstract

Background:The difference between renal oncocytomas (RO) and renal clear cell carcinomas (RCCs) presents the greatest diagnostic challenge. The aim of this study was to retrospectively determine if RO and RCCs could be differentiated on computed tomography (CT) images on the basis of their enhancement patterns with a new enhancement correcting method.Methods:Forty-six patients with a solitary renal mass who underwent total or partial nephrectomy were included in this study. Fourteen of those were RO and 32 were RCCs. All patients were examined with contrast-enhanced CT. The pattern and degree of enhancement were evaluated. We selected the area that demonstrated the greatest degree of enhancement of the renal lesion in the corticomedullary nephrographic and excretory phase images. Regions of interest (ROI) were also placed in adjacent normal renal cortex for normalization. We used the values of the normal renal cortex that were measured at the same time as divisors. The ratios of lesion-to-renal cortex enhancement were calculated for all three phases. The Student's t-test and Pearson's Chi-square test were used for statistical analyses.Results:All RCCs masses showed contrast that appeared to be better enhanced than RO on all contrast-enhanced phases of CT imaging, but there was no significant difference in absolute attenuation values between these two diseases (P > 0.05). The ratio of lesion-to-cortex attenuation in the corticomedullary phase showed significantly different values between RO and RCCs. The degree of contrast enhancement in RCCs was equal to or greater than that of the normal renal cortex, but it was less than that of the normal cortex in RO in the corticomedullary phase. The ratio of lesion-to-cortex attenuation in the corticomedullary phase was higher than the cut off value of 1.0 in most RCCs (84%, 27/32) and lower than 1.0 in most RO (93%, 13/14) (P < 0.05). In the nephrographic phase, the ratio of lesion-to-cortex attenuation was higher than that in the corticomedullary phase in most RO (71%, 10/14), showing a prolonged enhancement pattern; and was lower than that in most RCCs (97%, 31/32), showing an early washout pattern (P < 0.05). In the differentiation of RO from RCCs, the sensitivity was 93%, specificity 84%, positive predictive value 72%, negative predictive value 84%, and accuracy for RO was 87, if the ratio of lesion-to-cortex attenuation in a cortex phase was lower than the cutoff value of 1.0. The sensitivity was 71%, specificity was 97%, positive predictive value was 91%, negative predictive value was 91%, and accuracy for RO was 89%, if the ratio of lesion-to-cortex attenuation in nephrographic phase was higher than that in the corticomedullary phase.Conclusions:The ratios of renal lesion-to-cortex attenuation ratios may be helpful in differentiating RO from RCCs.

Multimodality Imaging Characteristics of the Common Renal Cell Carcinoma Subtypes: An Analysis of 544 Pathologically Proven Tumors

“…[1315161832] Among RCCs, a central stellate scar appeared to be an exclusive feature of the chromophobe subtype although it may also be found in oncocytoma. [192021] All cases involving a central stellate scar on imaging were confirmed histologically.…”

“…[18] Spoke-wheel enhancement and a central stellate scar – imaging findings initially observed in oncocytomas have recently been recognized in chromophobe RCCs as well. [192021] Several studies evaluated the degree of RCC enhancement subjectively and quantitatively[13222324252627] while others correlated magnetic resonance imaging (MRI) findings such as diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values, with the RCC subtype. [28293031] Thus, the objectives of this present study were: (1) to define the characteristic imaging appearances of the various RCC subtypes including quantifying the degree of tumor enhancement, (2) to integrate the imaging findings with relevant demographic and clinical parameters, and (3) to frame the results of this study in the context of the existing literature.…”

Giant cell tumour of the bone treated with denosumab: How has the blood supply and oncological prognosis of the tumour changed?

“…If the blood supply of tumour and blood loss can be reduced, the operation will be more calm and safe. The CT enhancement rate can reflect on blood supply of tumour and even suggest the characteristic and prognosis of some tumours [21], [22]. The CT value of the same lesion areas were measured before and after treatment in the same CT machine.…”

Value of Triphasic MDCT in the Differentiation of Small Renal Cell Carcinoma and Oncocytoma

“…Conversely, McGahan et al found the presence of segmental enhancement inversion pattern in only one of 16 small ROs (24). In the study by Ren et al, no tumors showed distinct segmental enhancement inversion (25).…”