title: Correlation between quantitative and semiquantitative parameters in DCE-MRI with a blood pool agent in rectal cancer: can semiquantitative parameters be used as a surrogate for quantitative parameters?
abstract: The aim of this study was to assess correlation between quantitative and semiquantitative parameters in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rectal cancer patients, both in a primary staging and restaging setting.
  
  
  
  Nineteen patients were included with DCE-MRI before and/or after neoadjuvant therapy. DCE-MRI was performed with gadofosveset trisodium (Ablavar®, Lantheus Medical Imaging, North Billerica, Massachusetts, USA). Regions of interest were placed in the tumor and quantitative parameters were extracted with Olea Sphere 2.2 software permeability module using the extended Tofts model. Semiquantitative parameters were calculated on a pixel-by-pixel basis. Spearman rank correlation tests were used for assessment of correlation between parameters. A p value ≤0.05 was considered statistically significant.
  
  
  
  Strong positive correlations were found between mean peak enhancement and mean Ktrans: 0.79 (all patients, p<0.0001), 0.83 (primary staging, p = 0.003), and 0.81 (restaging, p = 0.054). Mean wash-in correlated significantly with mean Vpand Kep(0.79 and 0.58, respectively, p<0.0001 and p = 0.009) in all patients. Mean wash-in showed a significant correlation with mean Kep(0.67, p = 0.033) in the primary staging group. On the restaging MRI, mean wash-in only strongly correlated with mean Vp(0.81, p = 0.054).
  
  
  
  This study shows a strong correlation between quantitative and semiquantitative parameters in DCE-MRI for rectal cancer. Peak enhancement correlates strongly with Ktransand wash-in showed strong correlation with Vpand Kep. These parameters have been reported to predict tumor aggressiveness and response in rectal cancer. Therefore, semiquantitative analyses might be a surrogate for quantitative analyses.
authors.affiliation: Department of Radiology, Maastricht University Medical Centre, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Rebecca A P
authors.initials: RAP
authors.lastname: Dijkhoff
authors.affiliation: Department of Radiology, The Netherlands Cancer Institute, P.O. Box 90203, 1066 CX, Amsterdam, The Netherlands. moniquemaas@live.nl.
authors.forename: Monique
authors.initials: M
authors.lastname: Maas
authors.affiliation: Department of Surgery, Zuyderland Medical Centre, P.O. Box 5500, 6130 MB, Sittard, The Netherlands.
authors.forename: Milou H
authors.initials: MH
authors.lastname: Martens
authors.affiliation: Division for Medical Imaging and Technology, Institute for Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, 171 77, Stockholm, Sweden.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Papanikolaou
authors.affiliation: Department of Radiology, The Netherlands Cancer Institute, P.O. Box 90203, 1066 CX, Amsterdam, The Netherlands.
authors.forename: Doenja M J
authors.initials: DMJ
authors.lastname: Lambregts
authors.affiliation: Department of Surgery, The Netherlands Cancer Institute, P.O. Box 90203, 1066 CX, Amsterdam, The Netherlands.
authors.forename: Geerard L
authors.initials: GL
authors.lastname: Beets
authors.affiliation: Department of Radiology, The Netherlands Cancer Institute, P.O. Box 90203, 1066 CX, Amsterdam, The Netherlands.
authors.forename: Regina G H
authors.initials: RGH
authors.lastname: Beets-Tan
mesh_terms: D000368:Aged; D001706:Biopsy; D059248:Chemoradiotherapy; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D009942:Organometallic Compounds / Q000008:administration & dosage*; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D005682:Gadolinium; C109932:gadofosveset trisodium
keywords: Correlation; Dynamic contrast-enhanced MRI; Quantitative; Rectal cancer; Semiquantitative