James Jago

Bio: James Jago is an academic researcher from Philips. The author has contributed to research in topics: Ultrasonic sensor & Harmonic. The author has an hindex of 26, co-authored 86 publications receiving 1901 citations. Previous affiliations of James Jago include Freeman Hospital.

Spatially compounded three dimensional ultrasonic images

Abstract: An ultrasonic probe is moved to scan a volumetric region of the body. As it is moved, targets within the region are interrogated from multiple look directions. The echo data from the multiple look directions are compounded to form spatially compounded image data, which is processed for display in a three dimensional display format.

Ultrasonic harmonic imaging with adaptive image formation

Abstract: An ultrasonic diagnostic imaging system receives fundamental frequency, harmonic contrast, and tissue harmonic echo information for image processing. The fundamental and harmonic signal content of the echo information is analyzed and the relative content of an output signal is adjusted as necessary to take advantage of the different characteristics of the different types of echo information present in the echo signal. The ultrasound system can produce images which are an adaptive blend of fundamental, tissue harmonic and harmonic contrast echo information.

A survey of the acoustic outputs of diagnostic ultrasound equipment in current clinical use

Abstract: Surveys published up to 1991 have highlighted a steady increase in the acoustic outputs from diagnostic ultrasound equipment. Since 1991 we have made measurements of the maximum peak negative pressure (p−) and spatial peak temporal average intensity (ISPTA) produced by 223 probes from 82 scanning systems in current clinical use in the Northern Region in the UK. Measurements have also been made of the maximum total acoustic power generated by 45 probes from 17 scanners. The results from these measurements are presented in this article and compared to the results of a similar survey of equipment from both the Northern and Wessex Regions in the UK and published in 1991. The comparison shows that measured ISPTA values have increased approximately sixfold in B mode and approximately threefold in colour Doppler mode. Also, measured total acoustic power values have doubled in pulsed Doppler mode. The present survey also draws attention to some particularly high ISPTA values obtained from a number of probes and scanning systems. This survey has shown that measurements of acoustic outputs from diagnostic ultrasound scanners in current clinical use are substantially higher than reported in earlier surveys and, for certain scanners, the acoustic outputs from scanned beam modes of operation can reach levels hitherto only found in pulsed Doppler mode.

Repeatability of peripheral pulse measurements on ears, fingers and toes using photoelectric plethysmography.

Abstract: Peripheral pulses have been analysed to determine the accuracy with which pulse transit times (PTTs) can be measured. Measurements of PTT between the ECG Q-wave and various peripheral sites were made in 10 normal subjects on 10 separate days. Mean values were determined for the ears (174 ms), fingers (245 ms), and toes (361 ms). The technique was sufficiently accurate to detect small changes in PTT due to changes in posture; sitting to lying, 5.2 ms. When comparing simultaneous measurements on bilateral sites only small differences in PTT were discovered, and these were not significant in the study group as a whole. However, these differences were significant in some individuals. When the subjects raised a single arm or leg, significant differences (38 ms and 49 ms respectively) were recorded between sides. The day-to-day repeatability sigma (expressed as the square root of the within-subject mean square variance) of individual PTT measurements on a subject (supine) was for ears, fingers and toes respectively 9.4, 9.2 and 12 ms. For right-left differences the repeatability was 7.2, 5.9 and 14 ms. Hence changes in PTTs, or differences between right and left sides, can be detected from single measurements with 95% confidence if they exceed approximately 20 ms in ears or fingers and 30 ms in toes.

Method for correcting blurring of spatially compounded ultrasonic diagnostic images

Abstract: An ultrasonic imaging method is described in which component ultrasonic images which are to be spatially compounded are corrected for misregistration prior to compounding. The component images may be registered to a reference image or registered to form intermediate compound images which are then registered and compounded. The misregistration may be sensed by calculating a similarity or difference metric for a region of interest of the image frames being registered, or on the basis of reference lines acquired for the purpose of registering images.

Photoplethysmography and its application in clinical physiological measurement.

Abstract: Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.

Statistical optics

Abstract: Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

Measurement and Interpretation of the Ankle-Brachial Index A Scientific Statement From the American Heart Association

Abstract: Measurement and interpretation of the ankle-brachial index : a scientific statement from the Ammerican Heart Association

Transducer array imaging system

Abstract: The embodiments contemplate methods and devices for communicating an acoustic emission via an array of transducers and wirelessly communicating data via a transceiver, where the transceiver may be in communication with the array of transducers. Embodiments also contemplate providing power for the acoustic emission via a power source and providing information regarding a temperature sensor to the transceiver. The wirelessly communicated data may include the information regarding the temperature sensor. Embodiments also contemplate processing the wirelessly communicated data at a relatively remote location with respect to both the power source and the temperature sensor.