title: Reproducibility of Parenchymal Blood Volume Measurements Using an Angiographic C-arm CT System.
abstract: Intra-procedural measurement of hepatic perfusion following liver embolization continues to be a challenge. Blood volume imaging before and after interventional procedures would allow identifying the treatment end point or even allow predicting treatment outcome. Recent liver oncology studies showed the feasibility of parenchymal blood volume (PBV) imaging using an angiographic C-arm system. This study was done to evaluate the reproducibility of PBV measurements using cone beam computed tomography (CBCT) before and after embolization of the liver in a swine model.
  
  
  
  CBCT imaging was performed before and after partial bland embolization of the left lobe of the liver in five adult pigs. Intra-arterial injection of iodinated contrast with a 6-second x-ray delay was used with a two-sweep 8-second rotation imaging protocol. Three acquisitions, each separated by 10 minutes to allow for contrast clearance, were obtained before and after embolization in each animal. Post-processing was carried out using dedicated software to generate three-dimensional (3D) PBV maps. Two region-of-interest measurements were placed on two views within the right and left lobe on each CBCT 3D PBV map. Variation in PBV for scans acquired within each animal was determined by the coefficient of variation and intraclass correlation. A Wilcoxon signed-rank test was used to test post-procedure reduction in PBV.
  
  
  
  The CBCT PBV maps showed mean coefficients of variation of 7% (range: 2%-16%) and 25% (range:  13%-34%) for baseline and embolized PBV maps, respectively. The intraclass correlation for PBV measurements was 0.89, demonstrating high reproducibility, with measurable reduction in PBV displayed after embolization (P = 0.007).
  
  
  
  Intra-procedural acquisition of 3D PBV maps before and after liver embolization using CBCT is highly reproducible and shows promising application for obtaining intra-procedural PBV maps during locoregional therapy.
authors.affiliation: Department of Radiology, Stanford University, 1201 Welch Road, Stanford, CA 94305. Electronic address: kmuell@stanford.edu.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Mueller
authors.affiliation: Department of Radiology, Stanford University, 1201 Welch Road, Stanford, CA 94305.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Fahrig
authors.affiliation: Siemens Healthcare GmbH, Forchheim, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Manhart
authors.affiliation: Siemens Healthcare GmbH, Forchheim, Germany.
authors.forename: Yu
authors.initials: Y
authors.lastname: Deuerling-Zheng
authors.affiliation: Department of Radiology, Stanford University, 1201 Welch Road, Stanford, CA 94305.
authors.forename: Jarrett
authors.initials: J
authors.lastname: Rosenberg
authors.affiliation: Siemens Medical Solutions Inc., Malvern, Pennsylvania.
authors.forename: Teri
authors.initials: T
authors.lastname: Moore
authors.affiliation: Department of Radiology, Stanford University, 1201 Welch Road, Stanford, CA 94305.
authors.forename: Arundhuti
authors.initials: A
authors.lastname: Ganguly
authors.affiliation: Department of Radiology, Stanford University, 1201 Welch Road, Stanford, CA 94305; Department of Radiology, Stanford University Medical Center, Stanford, California.
authors.forename: Nishita
authors.initials: N
authors.lastname: Kothary
mesh_terms: D000818:Animals; D001811:Blood Volume Determination / Q000379:methods*; D000072226:Computed Tomography Angiography / Q000379:methods*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003287:Contrast Media; D004621:Embolization, Therapeutic; D005260:Female; D021621:Imaging, Three-Dimensional; D007269:Injections, Intra-Arterial; D008102:Liver Circulation; D023421:Models, Animal; D015203:Reproducibility of Results; D012984:Software; D013552:Swine
chemical_list: D003287:Contrast Media
keywords: CBCT; Parenchymal blood volume (PBV); chemoembolization; porcine study