title: Measuring portal venous perfusion with contrast-enhanced CT: comparison of direct and indirect methods.
abstract: OBJECTIVE
  Two algorithms can be used to measure portal venous perfusion (PVP) with contrast material-enhanced single-level liver computed tomography. The "direct" and "indirect" algorithms use data from the portal vein and aorta, respectively. This study compared PVP values obtained with direct and with indirect algorithms in a series of patients.
  
  
  METHODS
  Both techniques were applied in 27 patients with cirrhosis (14 men and 13 women; mean age, 56.1 years +/- 9.4) and 18 control patients (seven men and 11 women; 52.8 years +/- 12.3). A single section through the liver was scanned after intravenous injection of ioversol (40-mL bolus; 320 mg of iodine per milliliter).
  
  
  RESULTS
  Both techniques showed reduced PVP in patients with cirrhosis (0.63 for direct and 0.17 for indirect method) compared with control patients (1.06 and 0.26, respectively), but only the direct method agreed with physiologic expectations based on animal and human studies. In separating cirrhotic and control patients, the area under the receiver operating characteristic curve was significantly greater for the direct method (0.91 vs 0.78; P = .03).
  
  
  CONCLUSIONS
  Both direct and indirect methods are feasible and distinguish well between cirrhotic and control patients, but the direct method is more physiologic and is preferable if portal venous data are available.
authors.affiliation: Department of Radiology, National Defense Medical College, Saitama, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tsushima
authors.forename: Martin J K
authors.initials: MJ
authors.lastname: Blomley
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kusano
authors.forename: Keigo
authors.initials: K
authors.lastname: Endo
mesh_terms: D000465:Algorithms; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017082:Portal Pressure; D011168:Portal System; D011169:Portal Vein / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed