title: Aorta-Lesion-Attenuation-Difference (ALAD) on contrast-enhanced CT: a potential imaging biomarker for differentiating malignant from benign oncocytic neoplasms.
abstract: To evaluate whether the Aorta-Lesion-Attenuation-Difference on contrast-enhanced CT can aid in the differentiation of malignant and benign oncocytic renal neoplasms.
  
  
  
  Two independent cohorts-an initial (biopsy) dataset and a validation (surgical) dataset-with oncocytomas and chromophobe renal cell carcinomas (chRCC) were included in this IRB-approved retrospective study. A region of interest was placed on the renal mass and abdominal aorta on the same CT image slice to calculate an Aorta-Lesion-Attenuation-Difference (ALAD). ROC curves were plotted for different enhancement phases, and diagnostic performance of ALAD for differentiating chRCC from oncocytomas was calculated.
  
  
  
  Seventy-nine renal masses (56 oncocytomas, 23 chRCC) were analyzed in the initial (biopsy) dataset. Thirty-six renal masses (16 oncocytomas, 20 chRCC) were reviewed in the validation (surgical) cohort. ALAD showed a statistically significant difference between oncocytomas and chromophobes during the nephrographic phase (p < 0.001), early excretory phase (p < 0.001), and excretory phase (p = 0.029). The area under the ROC curve for the nephrographic phase was 1.00 (95% CI: 1.00-1.00) for the biopsy dataset and showed the narrowest confidence interval. At a threshold value of 25.5 HU, sensitivity was 100 (82.2%-100%) and specificity was 81.5 (61.9%-93.7%). When tested on the validation dataset on measurements made by an independent reader, the AUROC was 0.93 (95% CI: 0.84-1.00) with a sensitivity of 100 (80.0%-100%) and a specificity of 87.5 (60.4%-97.8%).
  
  
  
  Nephrographic phase ALAD has potential to differentiate benign and malignant oncocytic renal neoplasms on contrast-enhanced CT if histologic evaluation on biopsy is indeterminate.
authors.affiliation: Department of Radiology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA. Dhyani.manish@mgh.harvard.edu.
authors.forename: Manish
authors.identifier: 0000-0002-2651-1859
authors.initials: M
authors.lastname: Dhyani
authors.affiliation: Department of Radiology, University of Florida College of Medicine, Gainesville, FL, 32610, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Grajo
authors.affiliation: Department of Urology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Dayron
authors.initials: D
authors.lastname: Rodriguez
authors.affiliation: Department of Radiology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Zhikui
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Urology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Feldman
authors.affiliation: Department of Pathology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Rosemary
authors.initials: R
authors.lastname: Tambouret
authors.affiliation: Department of Radiology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Debra A
authors.initials: DA
authors.lastname: Gervais
authors.affiliation: Department of Radiology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Arellano
authors.affiliation: Department of Radiology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Hahn
authors.affiliation: Department of Radiology, Massachusetts General Hospital [MGH], Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Samir
mesh_terms: D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000000981:diagnostic imaging; D001706:Biopsy; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Biomarker; Chromophobe; Computed tomography (CT); Oncocytic neoplasm; Oncocytoma; Renal cell Caecinoma