Diagnostic accuracy of contrast-enhanced computed tomography and contrast-enhanced magnetic resonance imaging of small renal masses in real practice: sensitivity and specificity according to subjective radiologic interpretation

Abstract

BackgroundThe aim of this study was to investigate the diagnostic accuracy of contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) of small renal masses in real practice.MethodsContrast-enhanced CT and MRI were performed between February 2008 and February 2013 on 68 patients who had suspected small (≤4 cm) renal cell carcinoma (RCC) based on ultrasonographic measurements. CT and MRI radiographs were reviewed, and the findings of small renal masses were re-categorized into five dichotomized scales by the same two radiologists who had interpreted the original images. Receiver operating characteristics curve analysis was performed, and sensitivity and specificity were determined.ResultsAmong the 68 patients, 60 (88.2 %) had RCC and eight had benign disease. The diagnostic accuracy rates of contrast-enhanced CT and MRI were 79.41 and 88.23 %, respectively. Diagnostic accuracy was greater when using contrast-enhanced MRI because too many masses (67.6 %) were characterized as “4 (probably solid cancer) or 5 (definitely solid cancer).” The sensitivity of contrast-enhanced CT and MRI for predicting RCC were 79.7 and 88.1 %, respectively. The specificities of contrast-enhanced CT and MRI for predicting RCC were 44.4 and 33.3 %, respectively. Fourteen diagnoses (20.5 %) were missed or inconsistent compared with the final pathological diagnoses. One appropriate nephroureterectomy and five unnecessary percutaneous biopsies were performed for RCC. Seven unnecessary partial nephrectomies were performed for benign disease.ConclusionsAlthough contrast-enhanced CT and MRI showed high sensitivity for detecting small renal masses, specificity remained low.

Von Hippel-Lindau syndrome and renal tumours: radiological diagnostic and treatment options. A case report and literature review

“…CT scan sensitivity reaches more than 90% in the diagnosis of renal tumours smaller than 2 cm and almost 99.9% when the tumour is larger than 2 cm, but diagnosis of RCCs sensitivity ranges from 60% to 79% and specificity ranges from 44% to 99.9%. That is why radiological diagnosis of renal tumours must be confirmed by a histological examination (19,20). The main advantage of CT examination over MRI or UG is the absorption of X-rays, which are expressed in Hounsfield units (different types of kidney cancer -light cells, papillary cells, and chromophobe cells -have different densities) (21).…”

Benign Lesions Detected in Patients Undergoing Nephrectomy for Renal Mass: Single Center Experiences

“…26 They also stated that the diagnostic accuracy of CT and MRI was weak in subjective radiological interpretation in clinical practice. 27 Since needle biopsy on which there is conflicting information on its use for the diagnosis of RCC doesn't conform to oncological principles and the risk of the tumor seeding during biopsy, it is not recommended for the diagnosis of suspected renal lesions. 28 Other indicators which may predict the histopathology of renal masses other than the imaging methods were also covered in literature.…”

Diagnostic Imaging for Solid Renal Tumors: A Pictorial Review

“…Findings in a study concerning the accuracy of CT for detecting renal tumors were based on a scoring system varying from "definitely not cancer" to "definitely solid cancer". That study reported an accuracy of 79% for detection of benign and malignant renal masses [35]. The detection of smaller tumors can especially pose a challenge [36,37].…”

“…The sensitivity and specificity for prediction of RCC in case of a renal tumor from CT findings has been described as 60% to 79% and 44% to 100%, respectively [35,42]. Although these findings may be influenced by tumor size, because a 1 cm increase in tumor size is associated with a 16% increase in the odd of malignancy [46].…”