Iodine quantification to distinguish clear cell from papillary renal cell carcinoma at dual-energy multidetector CT: a multireader diagnostic performance study.

PURPOSE To investigate whether dual-energy multidetector row computed tomographic (CT) imaging with iodine quantification is able to distinguish between clear cell and papillary renal cell carcinoma ( RCC renal cell carcinoma ) subtypes. MATERIALS AND METHODS In this retrospective, HIPAA-compliant, institutional review board-approved study, 88 patients (57 men, 31 women) with diagnosis of either clear cell or papillary RCC renal cell carcinoma at pathologic analysis, who underwent contrast material-enhanced dual-energy nephrographic phase study between December 2007 and June 2013, were included. Five readers, blinded to pathologic diagnosis, independently evaluated all cases by determining the lesion iodine concentration on color-coded iodine maps. The receiving operating characteristic curve analysis was adopted to estimate the optimal threshold for discriminating between clear cell and papillary RCC renal cell carcinoma , and results were validated by using a leave-one-out cross-validation. Interobserver agreement was assessed by using an intraclass correlation coefficient. The correlation between tumor iodine concentration and tumor grade was investigated. RESULTS A tumor iodine concentration of 0.9 mg/mL represented the optimal threshold to discriminate between clear cell and papillary RCC renal cell carcinoma , and it yielded the following: sensitivity, 98.2% (987 of 1005 [95% confidence interval: 97.7%, 98.7%]); specificity, 86.3% (272 of 315 [95% confidence interval: 85.0%, 87.7%]); positive predictive value, 95.8% (987 of 1030 [95% confidence interval: 95.0%, 96.6%]); negative predictive value, 93.7% (272 of 290 [95% confidence interval: 92.8%, 94.7%]); overall accuracy of 95.3% (1259 of 1320 [95% confidence interval: 94.6%, 96.2%]), with an area under the curve of 0.923 (95% confidence interval: 0.913, 0.933). An excellent agreement was found among the five readers in measured tumor iodine concentration (intraclass correlation coefficient, 0.9990 [95% confidence interval: 0. 9987, 0.9993). A significant correlation was found between tumor iodine concentration and tumor grade for both clear cell (τ = 0.85; P < .001) and papillary RCC renal cell carcinoma (τ = 0.53; P < .001). CONCLUSION Dual-energy multidetector CT with iodine quantification can be used to distinguish between clear cell and papillary RCC renal cell carcinoma , and it provides insights regarding the tumor grade.

[1]  S. Mazziotti,et al.  Single-phase dual-energy CT urography in the evaluation of haematuria. , 2013, Clinical radiology.

[2]  V. Goh,et al.  Assessment of response to tyrosine kinase inhibitors in metastatic renal cell cancer: CT texture as a predictive biomarker. , 2011, Radiology.

[3]  P. Russo,et al.  Role of Immunohistochemistry in the Evaluation of Needle Core Biopsies in Adult Renal Cortical Tumors: An Ex Vivo Study , 2011, The American journal of surgical pathology.

[4]  Holger Moch,et al.  The Heidelberg classification of renal cell tumours , 1997, The Journal of pathology.

[5]  Daniel Margolis,et al.  Clear cell renal cell carcinoma: discrimination from other renal cell carcinoma subtypes and oncocytoma at multiphasic multidetector CT. , 2013, Radiology.

[6]  D. Rennie,et al.  Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative , 2003, BMJ : British Medical Journal.

[7]  V. Goh,et al.  Novel oncologic drugs: what they do and how they affect images. , 2011, Radiographics : a review publication of the Radiological Society of North America, Inc.

[8]  Bernhard Krauss,et al.  Distinguishing enhancing from nonenhancing renal masses with dual-source dual-energy CT: iodine quantification versus standard enhancement measurements , 2013, European Radiology.

[9]  F. McGovern,et al.  Renal-cell carcinoma. , 2005, The New England journal of medicine.

[10]  S. Caloggero,et al.  Dual-energy CT for detection of endoleaks after endovascular abdominal aneurysm repair: usefulness of colored iodine overlay. , 2011, AJR. American journal of roentgenology.

[11]  Berthold Kiefer,et al.  Histogram analysis of whole-lesion enhancement in differentiating clear cell from papillary subtype of renal cell cancer. , 2012, Radiology.

[12]  Chaya S Moskowitz,et al.  Solid renal cortical tumors: differentiation with CT. , 2007, Radiology.

[13]  J. Larkin,et al.  Challenges and opportunities for converting renal cell carcinoma into a chronic disease with targeted therapies , 2011, British Journal of Cancer.

[14]  Ivan Pedrosa,et al.  Renal cell carcinoma: dynamic contrast-enhanced MR imaging for differentiation of tumor subtypes--correlation with pathologic findings. , 2009, Radiology.

[15]  M. Gaeta,et al.  Dual-source dual-energy CT evaluation of complex cystic renal masses. , 2012, AJR. American journal of roentgenology.

[16]  N. Obuchowski,et al.  Enhancement characteristics of papillary renal neoplasms revealed on triphasic helical CT of the kidneys. , 2002, AJR. American journal of roentgenology.

[17]  E. Basch,et al.  Targeted drugs for metastatic renal cell carcinoma , 2007, The Lancet.

[18]  M. Macari,et al.  Iodine quantification with dual-energy CT: phantom study and preliminary experience with renal masses. , 2011, AJR. American journal of roentgenology.

[19]  Christianne Leidecker,et al.  Dual-energy CT in patients suspected of having renal masses: can virtual nonenhanced images replace true nonenhanced images? , 2009, Radiology.

[20]  R. Nelson,et al.  Dual energy MDCT assessment of renal lesions: an overview , 2014, European Radiology.

[21]  Johannes B Reitsma,et al.  Overinterpretation and misreporting of diagnostic accuracy studies: evidence of "spin". , 2013, Radiology.

[22]  M. Baker,et al.  The current role of percutaneous biopsy in the evaluation of renal masses. , 1995, Seminars in urologic oncology.

[23]  H. Kressel.  Beyond the impact factor: enhancing the impact of imaging research published in Radiology. , 2014, Radiology.

[24]  T. Powles,et al.  Sunitinib and other targeted therapies for renal cell carcinoma , 2011, British Journal of Cancer.

[25]  M. Harisinghani,et al.  Renal mass biopsy to guide treatment decisions for small incidental renal tumors: a cost-effectiveness analysis. , 2010, Radiology.

[26]  Apurva A Desai,et al.  Sorafenib in advanced clear-cell renal-cell carcinoma. , 2007, The New England journal of medicine.

[27]  A. Evans,et al.  Outcomes of small renal mass needle core biopsy, nondiagnostic percutaneous biopsy, and the role of repeat biopsy. , 2011, European urology.

[28]  A. Ruppert-Kohlmayr,et al.  Differentiation of renal clear cell carcinoma and renal papillary carcinoma using quantitative CT enhancement parameters. , 2004, AJR. American journal of roentgenology.

[29]  Richard H Cohan,et al.  Distinguishing enhancing from nonenhancing renal lesions with fast kilovoltage-switching dual-energy CT. , 2011, AJR. American journal of roentgenology.

[30]  Kyoung-Sik Cho,et al.  Differentiation of subtypes of renal cell carcinoma on helical CT scans. , 2002, AJR. American journal of roentgenology.

[31]  T. Choueiri,et al.  Recent advances in the systemic treatment of metastatic papillary renal cancer , 2009, Expert review of anticancer therapy.

[32]  S. Fuhrman,et al.  Prognostic significance of morphologic parameters in renal cell carcinoma , 1982, The American journal of surgical pathology.

[33]  H. Hricak,et al.  CT findings of chemotherapy-induced toxicity: what radiologists need to know about the clinical and radiologic manifestations of chemotherapy toxicity. , 2011, Radiology.