title: In vivo validation of a transit-time ultrasonic volume flow meter.
abstract: The objective of this investigation was to validate a transit-time ultrasound blood flow metering system in vivo. Implanted chronically and acutely on the ascending aorta of the dog, the transit-time flow probe determined varying flow rates simultaneously with measurements made by the electromagnetic flow metering method. The transit-time technique was also compared to two methods in which blood was collected volumetrically by either graduated cylinder (ascending aorta/dog) or pump withdrawal (abdominal aorta/cat). Statistical analysis of the results provided evidence that the transit-time ultrasound method measured in vivo blood flow rate no differently than the electromagnetic or pump withdrawal techniques, however, transit-time determinations of blood volume were 10% below that indicated by graduated cylinder collection. With transit time represented on the y-axis, three linear regressions of all paired blood flow measurements were calculated yielding the following slopes (delta y/delta x) and regression coefficients (r), respectively: electromagnetic (1.00, 0.98), graduated cylinder (0.85, 0.93), and pump withdrawal (0.93, 1.00). The results validate the transit-time ultrasound system used in the present investigation as an accurate method capable of measuring blood flow in both acutely and chronically instrumented animal preparations.
authors.affiliation: Upjohn Laboratories, Kalamazoo, Michigan.
authors.forename: J C
authors.initials: JC
authors.lastname: Hartman
authors.forename: D A
authors.initials: DA
authors.lastname: Olszanski
authors.forename: T G
authors.initials: TG
authors.lastname: Hullinger
authors.forename: M N
authors.initials: MN
authors.lastname: Brunden
mesh_terms: D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging / Q000502:physiology; D001783:Blood Flow Velocity; D002415:Cats; D004285:Dogs; D055590:Electromagnetic Phenomena; D005260:Female; D018056:Hemorheology / Q000295:instrumentation*; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D013997:Time Factors; D014463:Ultrasonography