Jerome Segal

Bio: Jerome Segal is an academic researcher from University of California, San Francisco. The author has contributed to research in topics: Ultrasonic sensor & Transducer. The author has an hindex of 9, co-authored 13 publications receiving 1671 citations. Previous affiliations of Jerome Segal include Sequoia Hospital.

Validation of a Doppler guide wire for intravascular measurement of coronary artery flow velocity.

Abstract: BACKGROUNDAn improved intravascular ultrasonic Doppler device could aid the clinical assessment of coronary hemodynamics. We evaluated a new device consisting of a 12-MHz piezoelectric transducer integrated onto the tip of a 0.018-in. flexible, steerable angioplasty guide wire.METHODS AND RESULTSDoppler spectra were recorded in model tubes with pulsatile blood flow and in-line electromagnetic flowmeter. In four straight tubes (i.d., 0.79-4.76 mm), the time average of spectral peak velocity (APV) was linearly related to blood flow (QEMF) (r2 greater than or equal to 0.98 for each tube). A Doppler-derived quantitative flow estimate (QD) was calculated as the product of vessel cross-sectional area and mean velocity, with mean velocity estimated as 0.5 x APV. The slope of QD versus QEMF for the four tubes was near unity. APV was less accurate in a 7.94-mm straight tube and in tortuous segments. In four dogs, the left circumflex coronary artery (LCx) was perfused from the femoral artery via a cannula with in-l...

Apparatus, system and method for measuring spatial average velocity and/or volumetric flow of blood in a vessel and screw joint for use therewith

Abstract: System for measuring a characteristic of flow of liquid in a vessel of a patient comprising a transducer positioned in a vessel in a patient for supplying ultrasonic energy. The transducer produces a substantially uniform beam which encompasses the vessel. The transducer receives ultrasonic energy back scattered from the red blood cells and provides an electrical output signal. A first moment detector is provided which receives the electrical output from the transducer and provides a first moment signal. Normalization is provided to the output of the first moment detector to provide an electrical output representing a characteristic of the flow of the liquid in the vessel.

Apparatus and method for continuously measuring volumetric blood flow using multiple transducers and catheter for use therewith

Abstract: Apparatus for measuring volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is adapted to be disposed in the vessel. First and second ultrasonic transducers are carried by the catheter on one side of the catheter and face the wall of the vessel so that the beams from the transducers each cross substantially the longitudinal axis of the vessel. The first transducer beam is inclined at an angle with respect to the longitudinal axis of the vessel. The second transducer beam is inclined in a direction which is generally perpendicular to the longitudinal axis of the vessel.

Apparatus, system and method for measuring spatial average velocity and/or volumetric flow of blood in a vessel

Abstract: System for measuring a characteristic of flow of liquid in a vessel of a patient comprising a transducer positioned in a vessel in a patient for supplying ultrasonic energy. The transducer produces a substantially uniform beam which encompasses the vessel. The transducer receives ultrasonic energy back scattered from the red blood cells and provides an electrical output signal. A first moment detector is provided which receives the electrical output from the transducer and provides a first moment signal. Normalization is provided to the output of the first moment detector to provide an electrical output representing a characteristic of the flow of the liquid in the vessel.

Joint construction for use with apparatus, system and method for measuring spatial average velocity and/or volumetric flow of blood in a vessel

Abstract: System for measuring a characteristic of flow of liquid in a vessel of a patient comprising a transducer positioned in a vessel in a patient for supplying ultrasonic energy. The transducer produces a substantially uniform beam which encompasses the vessel. The transducer receives ultrasonic energy back scattered from the red blood cells and provides an electrical output signal. A first moment detector is provided which receives the electrical output from the transducer and provides a first moment signal. Normalization is provided to the output of the first moment detector to provide an electrical output representing a characteristic of the flow of the liquid in the vessel.

Long-Term Follow-Up of Patients With Mild Coronary Artery Disease and Endothelial Dysfunction

Abstract: Background—Coronary endothelial dysfunction is characterized by vasoconstrictive response to the endothelium-dependent vasodilator acetylcholine. Although endothelial dysfunction is considered an early phase of coronary atherosclerosis, there is a paucity of information regarding the outcome of these patients. Thus, this study was designed to evaluate the outcome of patients with mild coronary artery disease on the basis of their endothelial function. Methods and Results—Follow-up was obtained in 157 patients with mildly diseased coronary arteries who had undergone coronary vascular reactivity evaluation by graded administration of intracoronary acetylcholine, adenosine, and nitroglycerin and intracoronary ultrasound at the time of diagnostic study. Patients were divided on the basis of their response to acetylcholine into 3 groups: group 1 (n=83), patients with normal endothelial function; group 2 (n=32), patients with mild endothelial dysfunction; and group 3 (n=42), patients with severe endothelial dys...

Prognostic Value of Coronary Vascular Endothelial Dysfunction

Abstract: Background— Whether patients at increased risk can be identified from a relatively low-risk population by coronary vascular function testing remains unknown. We investigated the relationship between coronary endothelial function and the occurrence of acute unpredictable cardiovascular events (cardiovascular death, myocardial infarction, stroke, and unstable angina) in patients with and without coronary atherosclerosis (CAD). Methods and Results— We measured the change in coronary vascular resistance (ΔCVR) and epicardial diameter with intracoronary acetylcholine (ACh, 15 μg/min) to test endothelium-dependent function and sodium nitroprusside (20 μg/min) and adenosine (2.2 mg/min) to test endothelium-independent vascular function in 308 patients undergoing cardiac catheterization (132 with and 176 without CAD). Patients underwent clinical follow-up for a mean of 46±3 months. Acute vascular events occurred in 35 patients. After multivariate analysis that included CAD and conventional risk factors for athero...

Intravascular imaging apparatus and methods for use and manufacture

Abstract: A device for ultrasonic imaging, and methods for the use an manufacture thereof, particularly of small coronary vessels. The device comprises an elongate member with a distal end that can be positioned within a small vessel of a patient's body while a proximal end is located outside the body, a transducer located at a distal end of the elongate member and operable to scan the distal coronary vessels with ultrasonic pulses, and a signal processor connected to a proximal end of the elongate member and to the transducer for generating and receiving pulses to and from the transducer. A motor may be also connected to the proximal end of the elongate member for rotating the transducer.

Ethinyl estradiol acutely attenuates abnormal coronary vasomotor responses to acetylcholine in postmenopausal women.

Abstract: BACKGROUNDEstrogen administration in postmenopausal women is associated with a 50% reduction in the clinical manifestations of coronary artery disease. The mechanisms are not known, although one potential explanation is estrogen-induced modulation of coronary vasoreactivity. Acetylcholine is an endothelium-dependent vasodilator that may be used to assess coronary vasoreactivity and elicits coronary responses that parallel those found with common daily vasomotor stimuli. Therefore, we tested whether estrogen attenuates abnormal coronary vasomotor responses to acetylcholine in postmenopausal women.METHODS AND RESULTSAcetylcholine-induced changes in coronary flow, resistance, and cross-sectional area were determined before and 15 minutes after intravenous administration of ethinyl estradiol (EE, 35 micrograms) in 15 postmenopausal women. The influence of estrogen on basal coronary flow, resistance, and epicardial cross-sectional area was also assessed by measuring these parameters before and after EE or plac...