Measurement of absolute vascular flow

Claim 1

A catheter for measuring total volumetric vascular flow at a location in a vessel of interest comprising: (a) a flow-measurement catheter including a relatively long, hollow tubular member having distal and proximal ends and describing a continuous lumen having a distal measurement lumen segment of known geometric cross section, the distal end of the distal segment of the lumen having one or more end access ports and one or more sidewall access ports at a point close to but spaced from the distal end thereof and providing side access to the interior of the measurement lumen, the measurement lumen thereby being capable of carrying the full flow of the vessel of interest between the one or more end ports and the one or more side access ports when the catheter is situated at the location of interest, the flow-measurement catheter further extending into and being sealably connected to a handle means at the proximal end thereof; (b) an obturator catheter comprising a relatively long, hollow tubular member having a distal and a proximal end and describing a continuous lumen therein and further being designed to be coaxially combined with the flow-measurement catheter and be longitudinally movable with respect to the flow-measurement catheter, the obturator catheter having the ability to occlude the one or more sidewall access ports in the flow-measurement catheter sidewall when the distal end of the obturator catheter is advanced so as to cover the one or more sidewall ports in the flow-measurement catheter; (c) transducer means associated with the distal measurement segment of the flow-measurement catheter means for generating and receiving a beam of ultrasonic energy in the lumen of the outer catheter, the transducer means being disposed in fixed relation to the longitudinal axis of the distal measurement segment of the lumen of the flow-measurement catheter such that the total volumetric blood flow between the one or more side access ports and the one or more distal end access ports in the flow-measurement catheter lumen can be accurately sensed; (d) means for energizing and communicating with the transducer means.

Claim 23

A method of measuring total volumetric flow at a particular location in a vessel of interest comprising the steps of: (a) introducing within the vessel of interest a flow-measurement catheter system having a distal end and having a flow-measurement lumen of known cross sectional geometry, the flow-measurement lumen being provided with one or more inlet and outlet ports configured to carry the entire flow of the vessel of interest, the flow-measurement catheter system carrying an ultrasonic transducer means mounted therein and disposed to measure the flow velocity therethrough, the flow-measurement catheter system further having obturation means axially adjustable with respect to the flow-measurement lumen to occlude one or more of said one or more inlet ports; (b) positioning the flow-measurement catheter system within the vessel of interest as desired for flow measurement; (c) axially adjusting the obturation means, as necessary, to allow the full flow of the vessel of interest to enter the flow-measurement lumen; (d) using the ultrasonic transducer means and the known geometry of the catheter lumen to measure the volumetric flow rate through the vessel of interest.

Claim 24

A method of measuring total volumetric flow at a particular location in a vessel of interest comprising the steps of: (a) introducing within the vessel of interest a flow-measurement catheter system having a distal end and having a flow-measurement lumen of known cross sectional geometry, the flow-measurement lumen being provided with one or more inlet and outlet ports configured to carry the entire flow of the vessel of interest, the flow-measurement catheter system carrying an ultrasonic transducer means mounted therein and disposed to measure the flow velocity therethrough, the flow-measurement catheter system further having obturation means axially adjustable with respect to the flow-measurement lumen to occlude one or more of said one or more inlet ports; (b) positioning the flow-measurement catheter system within the vessel of interest as desired for flow measurement; (c) axially adjusting the obturation means, as necessary, to allow the full flow of the vessel of interest to enter the flow-measurement lumen; (d) using the ultrasonic transducer means and the known geometry of the catheter lumen to measure the volumetric flow rate through the vessel of interest.