Safety Assessment of Advanced Imaging Sequences I: Measurements

Jensen, Jørgen Arendt; Rasmussen, Morten Fischer; Pihl, Michael Johannes; Holbek, Simon; Hoyos, Carlos Armando Villagómez; Bradway, David; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev

doi:10.1109/tuffc.2015.2502987

Cited by 24 publications

(18 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…21 These limits concern the mechanical index, M I ≤ 1.9, the derated spatial-peak-temporal-average intensity, I spta ≤ 720 mW/cm 2 . The measured values using the scheme described by Jensen,22 are M I = 0.62 and a I spta = 106.8 mW/cm 2 , which are both below the FDA limits. The transducer surface temperature was also tested, where the transducer surface did not exceeded an increase of 30…”

Section: In-vivomentioning

confidence: 72%

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

et al. 2016

View full text Add to dashboard Cite

This work presents the first in vivo results of 2-D high frame rate vector velocity imaging for transthoracic cardiac imaging. Measurements are made on a healthy volunteer using the SARUS experimental ultrasound scanner connected to an intercostal phased-array probe. Two parasternal long-axis view (PLAX) are obtained, one centred at the aortic valve and another centred at the left ventricle. The acquisition sequence was composed of 3 diverging waves for high frame rate synthetic aperture flow imaging. For verification a phantom measurement is performed on a transverse straight 5 mm diameter vessel at a depth of 100 mm in a tissue-mimicking phantom.A flow pump produced a 2 ml/s constant flow with a peak velocity of 0.2 m/s. The average estimated flow angle in the ROI was 86.22• ± 6.66• with a true flow angle of 90 • . A relative velocity bias of −39% with a standard deviation of 13% was found. In-vivo acquisitions show complex flow patterns in the heart. In the aortic valve view, blood is seen exiting the left ventricle cavity through the aortic valve into the aorta during the systolic phase of the cardiac cycle. In the left ventricle view, blood flow is seen entering the left ventricle cavity through the mitral valve and splitting in two ways when approximating the left ventricle wall. The work presents 2-D velocity estimates on the heart from a non-invasive transthoracic scan. The ability of the method detecting flow regardless of the beam angle could potentially reveal a more complete view of the flow patterns presented on the heart.

show abstract

Section: In-vivomentioning

confidence: 72%

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The transmit pressure measurements of the lens was carried out using an AIMS III intensity measurement system (Onda Corporation, Sunnyvale, California, USA) connected to the experimental research scanner SARUS [13], [14]. The OptiSon ultrasound beam analyzer (Onda Corporation, Sunnyvale, California, USA) was used to validate the diverging properties of the lens in a water tank.…”

Section: Methodsmentioning

confidence: 99%

3-D imaging using row-column-addressed 2-D arrays with a diverging lens: Phantom study

Bouzari

Engholm

Beers

et al. 2017

2017 IEEE International Ultrasonics Symposium (IUS)

Self Cite

View full text Add to dashboard Cite

Abstract-A double-curved diverging lens over a flat rowcolumn-addressed (RCA) 2-D array can extend its inherent rectilinear 3-D imaging field-of-view (FOV) to a curvilinear volume region, which is necessary for applications such as abdominal and cardiac imaging. A concave lens with radius of 12.7 mm was manufactured using RTV664 silicone. The diverging properties of the lens were evaluated based on measurements on several phantoms. The measured 6 dB FOV in contact with a material similar to human soft tissue was less than 15% different from the theoretical predictions, i.e., a curvilinear FOV of 32°×32°. A synthetic aperture imaging sequence with single element transmissions was designed for imaging down to 14 cm at a volume rate of 88 Hz. The performance was evaluated in terms of signal-to-noise ratio (SNR), FOV, and full-widthat-half-maximum (FWHM). The penetration depth in a tissue mimicking phantom with 0.5 dB/(cm MHz) attenuation was 13 cm. The results of this study confirm that the proposed lens approach is an effective method for increasing the FOV, when imaging with RCA 2-D arrays.

show abstract

“…Content may change prior to final publication. Before starting the clinical trials, measures are conducted to adjust the transmit levels such that intensities and temperature constraints are obeyed [43]- [46]. Once parameters of the two competing methods are fixed, a few in-vivo measurements are obtained to study the preliminary efficacy.…”

Section: A Phase I: Demonstration Of Prototypementioning

confidence: 99%

A Methodology for Anatomic Ultrasound Image Diagnostic Quality Assessment

Hemmsen

Lange

Brandt

et al. 2017

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

Self Cite

View full text Add to dashboard Cite

Abstract-This paper discusses methods for assessment of ultrasound image quality based on our experiences with evaluating new methods for anatomic imaging. It presents a methodology to ensure a fair assessment between competing imaging methods using clinically relevant evaluations. The methodology is valuable in the continuing process of method optimization and guided development of new imaging methods. It includes a three phased study plan covering from initial prototype development to clinical assessment. Recommendations to the clinical assessment protocol, software, and statistical analysis are presented. Earlier uses of the methodology has shown that it ensures validity of the assessment, as it separates the influences between developer, investigator, and assessor once a research protocol has been established. This separation reduces confounding influences on the result from the developer to properly reveal the clinical value. The paper exemplifies the methodology using recent studies of Synthetic Aperture Sequential Beamforming tissue harmonic imaging.

show abstract

Safety Assessment of Advanced Imaging Sequences I: Measurements

Cited by 24 publications

References 19 publications

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

3-D imaging using row-column-addressed 2-D arrays with a diverging lens: Phantom study

A Methodology for Anatomic Ultrasound Image Diagnostic Quality Assessment

Contact Info

Product

Resources

About