title: Investigating the efficacy of subharmonic aided pressure estimation for portal vein pressures and portal hypertension monitoring.
abstract: The efficacy of using subharmonic emissions from Sonazoid microbubbles (GE Healthcare, Oslo, Norway) to track portal vein pressures and pressure changes was investigated in 14 canines using either slow- or high-flow models of portal hypertension (PH). A modified Logiq 9 scanner (GE Healthcare, Milwaukee, WI, USA) operating in subharmonic mode (f(transmit): 2.5 MHz, f(receive): 1.25 MHz) was used to collect radiofrequency data at 10-40% incident acoustic power levels with 2-4 transmit cycles (in triplicate) before and after inducing PH. A pressure catheter (Millar Instruments, Inc., Houston, TX, USA) provided reference portal vein pressures. At optimum insonification, subharmonic signal amplitude changes correlated with portal vein pressure changes; r ranged from -0.82 to -0.94 and from -0.70 to -0.73 for PH models considered separately or together, respectively. The subharmonic signal amplitudes correlated with absolute portal vein pressures (r: -0.71 to -0.79). Statistically significant differences between subharmonic amplitudes, before and after inducing PH, were noted (p ≤ 0.01). Portal vein pressures estimated using subharmonic aided pressure estimation did not reveal significant differences (p > 0.05) with respect to the pressures obtained using the Millar pressure catheter. Subharmonic-aided pressure estimation may be useful clinically for portal vein pressure monitoring.
authors.affiliation: Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Jaydev K
authors.initials: JK
authors.lastname: Dave
authors.forename: Valgerdur G
authors.initials: VG
authors.lastname: Halldorsdottir
authors.forename: John R
authors.initials: JR
authors.lastname: Eisenbrey
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Merton
authors.forename: Ji-Bin
authors.initials: JB
authors.lastname: Liu
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Zhou
authors.forename: Hsin-Kai
authors.initials: HK
authors.lastname: Wang
authors.forename: Suhyun
authors.initials: S
authors.lastname: Park
authors.forename: Scott
authors.initials: S
authors.lastname: Dianis
authors.forename: Carl L
authors.initials: CL
authors.lastname: Chalek
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.forename: Kai E
authors.initials: KE
authors.lastname: Thomenius
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Brown
authors.forename: Flemming
authors.initials: F
authors.lastname: Forsberg
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D003287:Contrast Media; D004285:Dogs; D005290:Ferric Compounds; D006975:Hypertension, Portal / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007501:Iron; D010087:Oxides; D011169:Portal Vein / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D010087:Oxides; C069727:Sonazoid; D007501:Iron