title: Parametric mapping of the hepatic perfusion index with gadolinium-enhanced volumetric MRI.
abstract: The purpose of this study was to adapt the hepatic perfusion index (HPI) methodology previously developed for MRI to derive 3D parametric maps of HPI, and to investigate apparent differences in HPI maps between a group of colorectal cancer patients and controls. To achieve this, a new and simpler approach to HPI calculation which does not require measurements from the aorta or portal vein is introduced, and assessed with large liver regions of interest (ROIs) in patients and controls. Several example HPI maps showing localized variation are then presented. The subject group consisted of 12 patients with known colorectal metastases, and 13 control subjects referred for routine contrast-enhanced spine imaging with no history of neoplastic disease. HPI was evaluated from serial T1 volume acquisitions acquired over the course of a Gd-DTPA bolus injection. Regions of abnormal perfusion were visible on the HPI maps derived for the patient group, manifested as areas of locally increased HPI extending around the visible margins of known metastases evident on the conventional contrast-enhanced images. This method for MR voxel-based parametric mapping of HPI has the potential to demonstrate regional variations in perfusion at the segmental and subsegmental level.
authors.affiliation: Cancer Research UK Clinical Magnetic Resonance Research Group, Royal Marsden NHS Trust & Institute of Cancer Research, Downs Road, Sutton, Surrey SM2 5PT, UK. mark.white@ucl.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: White
authors.forename: R L
authors.initials: RL
authors.lastname: O'Gorman
authors.forename: E M
authors.initials: EM
authors.lastname: Charles-Edwards
authors.forename: P A
authors.initials: PA
authors.lastname: Kane
authors.forename: J B
authors.initials: JB
authors.lastname: Karani
authors.forename: M O
authors.initials: MO
authors.lastname: Leach
authors.forename: J J
authors.initials: JJ
authors.lastname: Totman
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015179:Colorectal Neoplasms; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D008102:Liver Circulation; D008113:Liver Neoplasms / Q000098:blood supply / Q000175:diagnosis / Q000556:secondary*; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media; D005682:Gadolinium