E2286. Quantitative Flow Parameters Differentiating Oncocytoma and Papillary Renal Cancer from Clear Cell Renal Cancer on Perfusion MDCT
  1. Alex Chung; University of California - Los Angeles
  2. Michael McNitt-Gray; University of California - Los Angeles
  3. Allan Pantuck; University of California - Los Angeles
  4. Brian Shuch; University of California - Los Angeles
  5. Emma Stackpole; University of California - Los Angeles
  6. Steve Raman; University of California - Los Angeles
To evaluate quantitative differences in perfusion CT (pCT) parameters for differentiation of clear cell renal cell carcinoma (ccRCC) from papillary RCC (pRCC) and oncocytoma (Onc).

Materials and Methods:
With IRB approval & HIPAA compliance, we derived a study cohort of 40 consecutive patients who underwent pCT (Force, Siemens Healthineers (SH), Erlangen, Germany) for a known or suspected indeterminate solid renal mass. Virtual reconstructions of the noncontrast, corticomedullary, & nephrographic phases were generated using Syngo Via (SH, Malvern, PA). Volumes of interest were drawn on the most enhancing portion of the mass as well as normal ipsilateral & contralateral renal cortex during the corticomedullary phase. Perfusion parameters of blood flow (BF), blood volume (BV), mean transit time (MTT), flow extraction (FE), time to peak (TTP), absolute peak Hounsfield Units (pHU) values were generated from the perfusion curves & normalized to the ipsilateral cortex (IpCx) except for pHU. Perfusion parameters were compared by ANOVA between tumors grouped by their pathology results & by two-tailed paired sample t test between tumors & ipsilateral cortex.

Of 44 patients who underwent pCT, 32, 6 & 6 were ccRCC, pRCC & Onc, respectively. Significant quantitative differences were as follows: Between ccRCC & pRCC in BF, BV, FE, pHU & TTP (all p<0.01), between ccRCC & Onc in BV (p<0.01) & TTP (p<0.03) and pHU (p=0.09), & between pRCC & Onc in BV (p<0.02) & pHU (p<0.05). MTT was similar among groups (p>0.05). Compared to IpCx, ccRCC had less TTP (p<0.01), pRCC had less BF (p=0.01), BV (p=0.02), FE (p<0.01) & pHU (p=0.04) & more TTP (p=0.02), & Onc had less BV (p<0.01).

Significant differences were demonstrated in all normalized perfusion parameters except for MTT between ccRCC & pRCC, in BV & TTP with pHU leaning towards significance between ccRCC & Onc, & in BV, FE & pFU between pRCC & Onc. Relative enhancement parameters of ccRCC, pRCC & Onco compared to IpCx demonstrated significant differences in certain parameters.Relative CT perfusion parameters differ by renal mass histological subtype & may help characterize common solid renal lesions if validated.