title: Tumor Vascularity in Renal Masses: Correlation of Arterial Spin-Labeled and Dynamic Contrast-Enhanced Magnetic Resonance Imaging Assessments.
abstract: Arterial spin-labeled (ASL) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) have been proposed to quantitatively assess vascularity in renal cell carcinoma (RCC). However, there are intrinsic differences between these 2 imaging methods, such as the relative contribution of vascular permeability and blood flow to signal intensity for DCE MRI. We found a correlation between ASL perfusion and the DCE-derived volume transfer constant and rate constant parameters in renal masses > 2 cm in size and these measures correlated with microvessel density in clear cell RCC.
  
  
  BACKGROUND
  The objective of this study was to investigate potential correlations between perfusion using arterial spin-labeled (ASL) magnetic resonance imaging (MRI) and dynamic contrast-enhanced (DCE) MRI-derived quantitative measures of vascularity in renal masses > 2 cm and to correlate these with microvessel density (MVD) in clear cell renal cell carcinoma (ccRCC).
  
  
  METHODS
  Informed written consent was obtained from all patients before imaging in this Health Insurance Portability and Accountability Act-compliant, institutional review board-approved, prospective study. Thirty-six consecutive patients scheduled for surgery of a known renal mass > 2 cm underwent 3T ASL and DCE MRI. ASL perfusion measures (PASL) of mean, peak, and low perfusion areas within the mass were correlated to DCE-derived volume transfer constant (K(trans)), rate constant (Kep), and fractional volume of the extravascular extracellular space (Ve) in the same locations using a region of interest analysis. MRI data were correlated to MVD measures in the same tumor regions in ccRCC. Spearman correlation was used to evaluate the correlation between PASL and DCE-derived measurements, and MVD. P < .05 was considered statistically significant.
  
  
  RESULTS
  Histopathologic diagnosis was obtained in 36 patients (25 men; mean age 58 ± 12 years). PASL correlated with K(trans) (ρ = 0.48 and P = .0091 for the entire tumor and ρ = 0.43 and P = .03 for the high flow area, respectively) and Kep (ρ = 0.46 and P = .01 for the entire tumor and ρ = 0.52 and P = .008 for the high flow area, respectively). PASL (ρ = 0.66; P = .0002), K(trans) (ρ = 0.61; P = .001), and Kep (ρ = 0.64; P = .0006) also correlated with MVD in high and low perfusion areas in ccRCC.
  
  
  CONCLUSIONS
  PASL correlated with the DCE-derived measures of vascular permeability and flow, K(trans) and Kep, in renal masses > 2 cm in size. Both measures correlated to MVD in clear cell histology.
authors.affiliation: Department of Radiology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Urology, UT Southwestern Medical Center, Dallas, TX; Department of Pathology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Payal
authors.initials: P
authors.lastname: Kapur
authors.affiliation: Department of Radiology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yuan
authors.affiliation: Department of Radiology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Yin
authors.initials: Y
authors.lastname: Xi
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Carvo
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Sabina
authors.initials: S
authors.lastname: Signoretti
authors.affiliation: Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX; Philips Medical Systems, Cleveland, OH.
authors.forename: Ivan
authors.initials: I
authors.lastname: Dimitrov
authors.affiliation: Department of Radiology, UT Southwestern Medical Center, Dallas, TX; Department of Urology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Cadeddu
authors.affiliation: Department of Urology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Margulis
authors.affiliation: iCAD, Nashua, NH.
authors.forename: Naira
authors.initials: N
authors.lastname: Muradyan
authors.affiliation: Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX; Developmental Biology, UT Southwestern Medical Center, Dallas, TX.
authors.forename: James
authors.initials: J
authors.lastname: Brugarolas
authors.affiliation: Department of Radiology, UT Southwestern Medical Center, Dallas, TX; Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX.
authors.forename: Ananth J
authors.initials: AJ
authors.lastname: Madhuranthakam
authors.affiliation: Department of Radiology, UT Southwestern Medical Center, Dallas, TX; Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX. Electronic address: ivan.pedrosa@UTSouthwestern.edu.
authors.forename: Ivan
authors.initials: I
authors.lastname: Pedrosa
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000098:blood supply* / Q000175:diagnosis; D003287:Contrast Media; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology; D007680:Kidney Neoplasms / Q000098:blood supply* / Q000175:diagnosis; D018810:Magnetic Resonance Angiography; D008297:Male; D055806:Microvessels / Q000473:pathology; D008875:Middle Aged; D011446:Prospective Studies; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels
keywords: Angiogenesis; Arterial spin labeling; Dynamic contrast-enhanced MRI; Kidney cancers; Microvessel density