title: Renal cell carcinoma: applicability of the apparent coefficient of the diffusion-weighted estimated by MRI for improving their differential diagnosis, histologic subtyping, and differentiation grade.
abstract: BACKGROUND
  Renal cell carcinoma (RCC) represents the most common malignant epithelial neoplasm of the kidney. Accurate assessment of the renal masses, defining the histologic subtype and the grade of differentiation of the tumor, is vital to ensure an adequate case management as well as for staging and prognosis. Recently, diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) tends to be increasingly appealing for the clinicians as an imaging procedure of choice for the diagnosis and staging of the RCC, which is predetermined by several advantages over CT. The goal of the survey was to assess the applicability of the apparent diffusion coefficient (ADC) of the DWI MRI for the differential diagnostics, histologic subtyping, and defining the grade of differentiation of the RCC.
  
  
  METHODS
  The study enrolled 288 adult patients with renal lesions: 188 patients with solid RCC-126 patients with clear cell subtype (ccRCC), 32 patients with papillary RCC (pRCC), 30 patients with chromophobe RCC (chRCC); 27 patient with cystic form or RCC (Bosniak cyst, category IV); 32 patients with renal angiomyolipoma (AML); 25 patients with renal oncocytoma (OC); and 16 patients with the renal abscess (AB). In total, 245 lesions were pathologically verified. As a reference, 19 healthy volunteers were included into the study. All patients underwent MRI of the kidneys, involving DWI with subsequent evaluation of the ADC.
  
  
  RESULTS
  There was a reliable difference (p < 0.05) in mean ADC values between the normal renal parenchyma (NRP), solid RCC of different histologic subtypes and grades, cystic RCC, and benign renal lesions. The mean ADC values obtained in the result of the study were (×10-3mm2/s): 2.47 ± 0.12 in NRP, 1.63 ± 0.29 in all solid RCCs, 1.82 ± 0.22 in solid ccRCC (1.92 ± 0.11-Fuhrman grade I, 1.84 ± 0.14-Fuhrman grade II, 1.79 ± 0.10-Fuhrman grade III, 1.72 ± 0.06-Fuhrman grade IV), 1.61 ± 0.07 in pRCC, 1.46 ± 0.09 in chRCC, 2.68 ± 0.11 in cystic RCC, 2.13 ± 0.08 in AML, 2.26 ± 0.06 in OC, and 3.30 ± 0.07 in AB.
  
  
  CONCLUSIONS
  The data received in our study demonstrate a substantial restriction of diffusion of hydrogen molecules in tissues of ccRCC in comparison with the healthy renal parenchyma preconditioned by the greater density of tumor. A statistically significant difference in mean ADC values of ccRCC with different grades of nuclear pleomorphism by Fuhrman was observed: Low-grade tumors showed higher mean ADC values compared to high-grade tumors. The modality of the MRI DWI along with ADC measurement allows to reliably differentiate between the solid RCC of main histologic subtypes and grades, cystic RCC, and the benign renal lesions.
authors.affiliation: Department of Urology, Lviv National Medical University, Pekarska str. 69, Lviv, Ukraine. mytsyk.yulian@i.ua.
authors.forename: Yulian
authors.initials: Y
authors.lastname: Mytsyk
authors.affiliation: Euroclinic Medical Center, Lviv, Ukraine.
authors.forename: Ihor
authors.initials: I
authors.lastname: Dutka
authors.affiliation: Department of Urology, Lviv National Medical University, Pekarska str. 69, Lviv, Ukraine.
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Borys
authors.affiliation: Euroclinic Medical Center, Lviv, Ukraine.
authors.forename: Iryna
authors.initials: I
authors.lastname: Komnatska
authors.affiliation: Department of Radiology, Lviv National Medical University, Lviv, Ukraine.
authors.forename: Iryna
authors.initials: I
authors.lastname: Shatynska-Mytsyk
authors.affiliation: Laboratory of Translational Oncology and Personalized Medicine, Rashid Latif Medical College, Lahore, Pakistan.
authors.forename: Ammad Ahmad
authors.initials: AA
authors.lastname: Farooqi
authors.affiliation: Department of Nutrition, Faculty of Nursing and Professional Health Studies, Slovak Medical University, Limbova 12, 833 03, Bratislava, Slovak Republic. katarina.gazdikova@szu.sk.|Department of General Medicine, Faculty of Medicine, Slovak Medical University, Bratislava, Slovak Republic. katarina.gazdikova@szu.sk.
authors.forename: Katarina
authors.initials: K
authors.lastname: Gazdikova
authors.affiliation: University of Oviedo, Central University Hospital of Asturias (HUCA), Oviedo, Spain.
authors.forename: Martin
authors.initials: M
authors.lastname: Caprnda
authors.affiliation: University of Oviedo, Central University Hospital of Asturias (HUCA), Oviedo, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Rodrigo
authors.affiliation: Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Palackeho tr 1946/1, 612 42, Brno, Czech Republic. kruzliakpeter@gmail.com.|2nd Department of Surgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic. kruzliakpeter@gmail.com.
authors.forename: Peter
authors.initials: P
authors.lastname: Kruzliak
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000473:pathology; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D061827:Dimensional Measurement Accuracy; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D018579:Patient Selection; D011379:Prognosis; D058996:Quality Improvement; D015203:Reproducibility of Results
keywords: Apparent diffusion coefficient; Diffusion-weighted imaging; Magnetic resonance imaging; Renal cell carcinoma