Jeffrey Bamber - Profile on Academia.edu (original) (raw)

Papers by Jeffrey Bamber

Comparing Volumetric Speckle Tracking Performance of Common Parallel-Acquisition Sequences using a Matrix Probe for Respiratory-Induced Liver Motion

2023 IEEE International Ultrasonics Symposium (IUS)

Journal of the Acoustical Society of America, May 1, 1981

Simulation of a tissue backscatter coefficient measurement experiment using the finite element method

The Journal of the Acoustical Society of America

Ultrasound has been shown to be an effective imaging modality for investigating tissue health. Fo... more Ultrasound has been shown to be an effective imaging modality for investigating tissue health. For example, the backscatter coefficient (BSC) has been shown to be a biomarker of tumour response to therapy but is limited in its application clinically due to the difficulty of accurately acquiring attenuation and diffraction corrections. To assess the variability in BSC assessment, we present a finite element tool simulating a singleelement planar reflector substitution method estimate of the BSC of a set of simulated phantoms. BSC estimates were computed with errors <5% of the theoretical value for a range of source apertures and over a set of phantoms with varying scatterer number densities to within 10%. In addition, the firstorder amplitude envelope statistics of backscattered waves were shown to be commensurate with Rayleigh scattering models. These results indicate that the tool is accurate in its replication of soft tissue-like scattering, suggesting that it could be an oppor...

Investigation of the planar reflector substitution method using the finite element method

The Journal of the Acoustical Society of America

The backscatter coefficient (BSC) has been shown to be an indicator of tissue state in assessing ... more The backscatter coefficient (BSC) has been shown to be an indicator of tissue state in assessing tumour response to therapy, but it is limited in its clinical applicability by the difficulty in acquiring the appropriate reference spectrum. The accuracy of a BSC estimate made by the substitution method is influenced by the quality of the reference spectrum, which normalises the measurement to the source’s diffraction field and spectral characteristics. Among the reference objects employed for normalisation, a planar reflector has been popular. With the sample region at the focus of a focused source or the last axial maximum of an unfocused source, the reflector has been placed either at this depth or half this depth by different authors. This work explores the effect of planar reflector positioning on BSC estimation. FE models were constructed to simulate BSC measurements of virtual phantoms with various sources, and the estimates compared to scattering theory. The results indicate t...

Phase I trial of acoustic cluster therapy (ACT) with chemotherapy in patients with liver metastases of gastrointestinal origin (ACTIVATE study)

Journal of Clinical Oncology

TPS3145 Background: Response to existing chemotherapeutics (chemo) can be limited by exposure, it... more TPS3145 Background: Response to existing chemotherapeutics (chemo) can be limited by exposure, itself limited by systemic toxicity. Interstitial fluid pressure can impede transport of drugs with, in some cases, <5% of systemic chemo penetrating the target tumour. ACT is an innovative platform technology using sonopermeation to induce ultrasound (US) mediated targeting of therapeutic agent of choice by co-administration of an emulsion of microbubble-microdroplet clusters (PS101) for intravenous injection. Dual-frequency US is applied to tumor tissue to concentrate the drug through expansion and oscillation of the clusters, increasing tumoral penetration. Early pre-clinical models of ACT indicate significant increase in uptake of co-administered product at the US targeted site and have demonstrated enhanced efficacy outcomes with co-administered ACT across a range of cancer models. All studies showed significant benefit in disease response and tumour regression/inhibition versus dr...

Sensors, 2020

Most modern energy resolving, photon counting detectors employ small (sub 1 mm) pixels for high s... more Most modern energy resolving, photon counting detectors employ small (sub 1 mm) pixels for high spatial resolution and low per pixel count rate requirements. These small pixels can suffer from a range of charge sharing effects (CSEs) that degrade both spectral analysis and imaging metrics. A range of charge sharing correction algorithms (CSCAs) have been proposed and validated by different groups to reduce CSEs, however their performance is often compared solely to the same system when no such corrections are made. In this paper, a combination of Monte Carlo and finite element methods are used to compare six different CSCAs with the case where no CSCA is employed, with respect to four different metrics: absolute detection efficiency, photopeak detection efficiency, relative coincidence counts, and binned spectral efficiency. The performance of the various CSCAs is explored when running on systems with pixel pitches ranging from 100 µm to 600µm, in 50 µm increments, and fluxes from 1...

IEEE Transactions on Radiation and Plasma Medical Sciences, 2021

An assessment of photoacoustic and photon counting multispectral x-ray imaging techniques for imaging gold nanorods in vivo as part of predicting dose enhancing effects

2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD), 2016

Radiotherapy, whilst useful in the treatment of many cancers, suffers from the drawback of unavoi... more Radiotherapy, whilst useful in the treatment of many cancers, suffers from the drawback of unavoidably delivering radiation doses to healthy tissue. Gold nanoparticles (GNPs) have been the subject of much interest as they are able to generate a local dose enhancing effect (DEE), allowing lower intensity beams to achieve a given effect, sparing healthy tissue. It is important that GNP distributions can be ascertained before radiotherapy begins so that accurate treatment plans can be made. Two imaging modalities that show great promise in being able to identify these GNPs in vivo without delivering excessive DEEs are photoacoustic imaging (PAI) and photon counting multi-spectral x-ray imaging (x-CSI). This work forms part of a larger project to assess the feasibility of using x-CSI and PAI to predict DEEs during radiotherapy planning. This work assessed the degradation of gold nanorods (GNRs) in a photoacoustic system sold by iThera, specifically comparing the protective effects against degradation afforded by a silica coating as opposed to GNR PEGylation. This coating is also hoped to prevent spectral broadening when the GNRs are endocytosed, allowing PAI to confirm uptake of GNRs by cells. With regards x-CSI, this work uses a combination of Monte Carlo and Finite Element modelling techniques to realistically model cylindrical phantoms of high-Z materials in order to demonstrate the potential improvements in imaging contrast that x-CSI can produce over traditional energy integrated x-ray imaging techniques. Results on the assessment of both techniques are discussed.

This study investigates the use a 2D normalized cross-correlation (NCC)-based algorithm to estima... more This study investigates the use a 2D normalized cross-correlation (NCC)-based algorithm to estimate in vivo motion of liver features in 2D Bmode ultrasound (US) images. Datasets included 23 volunteer imaging sequences, each containing first frame annotated points of interest (POI). Images had a range of spatial (0.28 – 0.71 mm) and temporal (11 – 25 Hz) resolution. Image quality was also highly variable. A 2D block-matching algorithm was developed to track POI motion throughout the imaging sequence. A correlation and displacement thresholding tracking approach, which used knowledge of previous displacement and (1) linear extrapolation, (2) a regularizing sinusoidal breathing model or (3) hybrid fixed-reference / incremental tracking was use to account for potential tracking errors. The overall mean error in vessel tracking was 2.15 ± 2.7 mm. This approach to motion estimation shows promise for applications such as radiation therapy tumor tracking.

Progress Towards Piezocomposite Transducers and Arrays for Real-time High Frequency Biomedical Ultrasound Imaging

In vivo ultrasound attenuation coefficient measurements are of interest as they can provide 1 ins... more In vivo ultrasound attenuation coefficient measurements are of interest as they can provide 1 insight into tissue pathology. They are also needed so that measurements of the tissue’s frequency 2 dependent ultrasound backscattering coefficient may be corrected for attenuation. In vivo 3 measurements of the attenuation coefficient are challenging because it has to be estimated from the 4 depth dependent decay of backscatter signals that display a large degree of magnitude variation. In this 5 study we describe and evaluate an improved backscatter method to estimate ultrasound attenuation 6 which is tolerant to the presence of some backscatter inhomogeneity. This employs an automated 7 algorithm to segment and remove atypically strong echoes to lessen the potential bias these may 8 introduce on the attenuation coefficient estimates. The benefit of the algorithm was evaluated by 9 measuring the frequency dependent attenuation coefficient of a gelatine phantom containing randomly 10 dist...

A Mask Based Ultrasound Array Design and Fabrication Process

No abstract available

LNCaP prostate cancer imaging with biologically functionalized gold nanoparticles in 2D and 3D cell culture

Anticancer Research, 2008

One of the main objectives of this project is to realize and validate a versatile lab system comp... more One of the main objectives of this project is to realize and validate a versatile lab system composed of functionalized nanoparticles for diagnosis of different superficial and accessible cancers, e.g. prostate cancer. Gold nanorods have been synthesized and functionalized with antibodies targeting specific antigens on cancer cell lines

Multi-band finite element simulation of ultrasound attenuation by soft tissue

2021 IEEE International Ultrasonics Symposium (IUS), 2021

The methods and results presented here test the ability of the multi-band finite element method t... more The methods and results presented here test the ability of the multi-band finite element method to simulate the frequency dependence of attenuation of ultrasound within soft tissue like materials, and the potential translation of the approach from its previous applications in non-destructive testing into medical ultrasound. Using a variety of materials, the approach was tested by comparing the theoretical attenuation (based on the input attenuation constants and path length through the materials) to the attenuation of the signal energy within the simulation. In two models, hypothetical materials were devised, with arbitrary attenuation properties and acoustic impedance matched to a background with the density and sound speed of water. In the third model, acoustic impedance mismatches were introduced to simulate the signal energy loss due to reflection and attenuation as an ultrasound beam passes from water into parallel layers of human skin, fat and muscle. In all cases, the calculated signal loss (from the reflection coefficients and attenuation constants) agreed with the signal loss measured within the simulation to a high degree, reproducing the input parameters to four significant figures in all cases.

Applied Sciences, 2021

Quantitative measures of radiation-induced breast stiffness are required to support clinical stud... more Quantitative measures of radiation-induced breast stiffness are required to support clinical studies of novel breast radiotherapy regimens and exploration of personalised therapy, however, variation between shear-wave elastography (SWE) machines may limit the usefulness of shear-wave speed (cs) for this purpose. Mean cs measured in four healthy volunteers’ breasts and a phantom using 2D-SWE machines Acuson S2000 (Siemens Medical Solutions) and Aixplorer (Supersonic Imagine) were compared. Shear-wave speed was measured in the skin region, subcutaneous adipose tissue and parenchyma. cs estimates were on average 2.3% greater when using the Aixplorer compared to S2000 in vitro. In vivo, cs estimates were on average 43.7%, 36.3% and 49.9% significantly greater (p << 0.01) when using the Aixplorer compared to S2000, for skin region, subcutaneous adipose tissue and parenchyma, respectively. In conclusion, despite relatively small differences between machines observed in vitro, large ...

Cancers, 2021

Background: ultrasound-based shear wave elastography (SWE) can non-invasively assess prostate tis... more Background: ultrasound-based shear wave elastography (SWE) can non-invasively assess prostate tissue stiffness. This systematic review aims to evaluate SWE for the detection of prostate cancer (PCa) and compare diagnostic estimates between studies reporting the detection of all PCa and clinically significant PCa (csPCa). Methods: a literature search was performed using the MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov, and CINAHL databases. Studies evaluating SWE for the detection of PCa using histopathology as reference standard were included. Results: 16 studies including 2277 patients were included for review. Nine studies evaluated SWE for the detection of PCa using systematic biopsy as a reference standard at the per-sample level, with a pooled sensitivity and specificity of 0.85 (95% CI = 0.74–0.92) and 0.85 (95% CI = 0.75–0.91), respectively. Five studies evaluated SWE for the detection of PCa using histopathology of radical prostatectomy (RP) specimens as the referen...

Ultrasonics, 2021

In vivo ultrasound attenuation coefficient measurements are of interest as they can provide insig... more In vivo ultrasound attenuation coefficient measurements are of interest as they can provide insight into tissue pathology. They are also needed so that measurements of the tissue's frequency dependent ultrasound backscattering coefficient may be corrected for attenuation. In vivo measurements of the attenuation coefficient are challenging because it has to be estimated from the depth dependent decay of backscatter signals that display a large degree of magnitude variation. In this study we describe and evaluate an improved backscatter method to estimate ultrasound attenuation which is tolerant to the presence of some backscatter inhomogeneity. This employs an automated algorithm to segment and remove atypically strong echoes to lessen the potential bias these may introduce on the attenuation coefficient estimates. The benefit of the algorithm was evaluated by measuring the frequency dependent attenuation coefficient of a gelatine phantom containing randomly distributed cellulose scatterers as a homogeneous backscattering component and planar pieces of cooked leek to provide backscattering inhomogeneities. In the phantom the segmentation algorithm was found to improve the accuracy and precision of attenuation coefficient estimates by up to 80% and 90%, respectively. The effect of the algorithm was then measured in vivo using 32 radiofrequency B-mode datasets from the breasts of two healthy female volunteers, producing a 5 to 25% reduction in mean attenuation coefficient estimates and a 30 to 50% reduction in standard deviation of attenuation coefficient across different positions within each breast. The results suggest that the segmentation algorithm may improve the accuracy and precision of attenuation coefficient estimates in vivo.

Photoacoustics, 2018

Epi-style optoacoustic (OA) imaging provides flexibility by integrating the irradiation optics an... more Epi-style optoacoustic (OA) imaging provides flexibility by integrating the irradiation optics and ultrasound receiver, yet clutter generated by optical absorption near the probe obscures deep OA sources. Localised vibration tagging (LOVIT) retrieves OA signal from images that are acquired with and without a preceding ultrasonic pushing beam: Radiation force leads to a phase shift of signals coming from the focal area resulting in their visibility in a difference image, whereas clutter from outside the pushing beam is eliminated. Disadvantages of a single-focus approach are residual clutter from inside the pushing beam above the focus, and time-intensive scanning of the focus to retrieve a large field-of-view. To speed up acquisition, we propose to create multiple foci in parallel, forming comb-shaped ARF patterns. By subtracting OA images obtained with interleaved combs, this technique moreover results in greatly improved clutter reduction in phantoms mimicking optical, acoustic an...

David Cosgrove

BMJ (Clinical research ed.), Aug 11, 2017

Comparing Volumetric Speckle Tracking Performance of Common Parallel-Acquisition Sequences using a Matrix Probe for Respiratory-Induced Liver Motion

2023 IEEE International Ultrasonics Symposium (IUS)

Journal of the Acoustical Society of America, May 1, 1981

Simulation of a tissue backscatter coefficient measurement experiment using the finite element method

The Journal of the Acoustical Society of America

Ultrasound has been shown to be an effective imaging modality for investigating tissue health. Fo... more Ultrasound has been shown to be an effective imaging modality for investigating tissue health. For example, the backscatter coefficient (BSC) has been shown to be a biomarker of tumour response to therapy but is limited in its application clinically due to the difficulty of accurately acquiring attenuation and diffraction corrections. To assess the variability in BSC assessment, we present a finite element tool simulating a singleelement planar reflector substitution method estimate of the BSC of a set of simulated phantoms. BSC estimates were computed with errors <5% of the theoretical value for a range of source apertures and over a set of phantoms with varying scatterer number densities to within 10%. In addition, the firstorder amplitude envelope statistics of backscattered waves were shown to be commensurate with Rayleigh scattering models. These results indicate that the tool is accurate in its replication of soft tissue-like scattering, suggesting that it could be an oppor...

Investigation of the planar reflector substitution method using the finite element method

The Journal of the Acoustical Society of America

The backscatter coefficient (BSC) has been shown to be an indicator of tissue state in assessing ... more The backscatter coefficient (BSC) has been shown to be an indicator of tissue state in assessing tumour response to therapy, but it is limited in its clinical applicability by the difficulty in acquiring the appropriate reference spectrum. The accuracy of a BSC estimate made by the substitution method is influenced by the quality of the reference spectrum, which normalises the measurement to the source’s diffraction field and spectral characteristics. Among the reference objects employed for normalisation, a planar reflector has been popular. With the sample region at the focus of a focused source or the last axial maximum of an unfocused source, the reflector has been placed either at this depth or half this depth by different authors. This work explores the effect of planar reflector positioning on BSC estimation. FE models were constructed to simulate BSC measurements of virtual phantoms with various sources, and the estimates compared to scattering theory. The results indicate t...

Phase I trial of acoustic cluster therapy (ACT) with chemotherapy in patients with liver metastases of gastrointestinal origin (ACTIVATE study)

Journal of Clinical Oncology

TPS3145 Background: Response to existing chemotherapeutics (chemo) can be limited by exposure, it... more TPS3145 Background: Response to existing chemotherapeutics (chemo) can be limited by exposure, itself limited by systemic toxicity. Interstitial fluid pressure can impede transport of drugs with, in some cases, <5% of systemic chemo penetrating the target tumour. ACT is an innovative platform technology using sonopermeation to induce ultrasound (US) mediated targeting of therapeutic agent of choice by co-administration of an emulsion of microbubble-microdroplet clusters (PS101) for intravenous injection. Dual-frequency US is applied to tumor tissue to concentrate the drug through expansion and oscillation of the clusters, increasing tumoral penetration. Early pre-clinical models of ACT indicate significant increase in uptake of co-administered product at the US targeted site and have demonstrated enhanced efficacy outcomes with co-administered ACT across a range of cancer models. All studies showed significant benefit in disease response and tumour regression/inhibition versus dr...

Sensors, 2020

Most modern energy resolving, photon counting detectors employ small (sub 1 mm) pixels for high s... more Most modern energy resolving, photon counting detectors employ small (sub 1 mm) pixels for high spatial resolution and low per pixel count rate requirements. These small pixels can suffer from a range of charge sharing effects (CSEs) that degrade both spectral analysis and imaging metrics. A range of charge sharing correction algorithms (CSCAs) have been proposed and validated by different groups to reduce CSEs, however their performance is often compared solely to the same system when no such corrections are made. In this paper, a combination of Monte Carlo and finite element methods are used to compare six different CSCAs with the case where no CSCA is employed, with respect to four different metrics: absolute detection efficiency, photopeak detection efficiency, relative coincidence counts, and binned spectral efficiency. The performance of the various CSCAs is explored when running on systems with pixel pitches ranging from 100 µm to 600µm, in 50 µm increments, and fluxes from 1...

IEEE Transactions on Radiation and Plasma Medical Sciences, 2021

An assessment of photoacoustic and photon counting multispectral x-ray imaging techniques for imaging gold nanorods in vivo as part of predicting dose enhancing effects

2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD), 2016

Radiotherapy, whilst useful in the treatment of many cancers, suffers from the drawback of unavoi... more Radiotherapy, whilst useful in the treatment of many cancers, suffers from the drawback of unavoidably delivering radiation doses to healthy tissue. Gold nanoparticles (GNPs) have been the subject of much interest as they are able to generate a local dose enhancing effect (DEE), allowing lower intensity beams to achieve a given effect, sparing healthy tissue. It is important that GNP distributions can be ascertained before radiotherapy begins so that accurate treatment plans can be made. Two imaging modalities that show great promise in being able to identify these GNPs in vivo without delivering excessive DEEs are photoacoustic imaging (PAI) and photon counting multi-spectral x-ray imaging (x-CSI). This work forms part of a larger project to assess the feasibility of using x-CSI and PAI to predict DEEs during radiotherapy planning. This work assessed the degradation of gold nanorods (GNRs) in a photoacoustic system sold by iThera, specifically comparing the protective effects against degradation afforded by a silica coating as opposed to GNR PEGylation. This coating is also hoped to prevent spectral broadening when the GNRs are endocytosed, allowing PAI to confirm uptake of GNRs by cells. With regards x-CSI, this work uses a combination of Monte Carlo and Finite Element modelling techniques to realistically model cylindrical phantoms of high-Z materials in order to demonstrate the potential improvements in imaging contrast that x-CSI can produce over traditional energy integrated x-ray imaging techniques. Results on the assessment of both techniques are discussed.

This study investigates the use a 2D normalized cross-correlation (NCC)-based algorithm to estima... more This study investigates the use a 2D normalized cross-correlation (NCC)-based algorithm to estimate in vivo motion of liver features in 2D Bmode ultrasound (US) images. Datasets included 23 volunteer imaging sequences, each containing first frame annotated points of interest (POI). Images had a range of spatial (0.28 – 0.71 mm) and temporal (11 – 25 Hz) resolution. Image quality was also highly variable. A 2D block-matching algorithm was developed to track POI motion throughout the imaging sequence. A correlation and displacement thresholding tracking approach, which used knowledge of previous displacement and (1) linear extrapolation, (2) a regularizing sinusoidal breathing model or (3) hybrid fixed-reference / incremental tracking was use to account for potential tracking errors. The overall mean error in vessel tracking was 2.15 ± 2.7 mm. This approach to motion estimation shows promise for applications such as radiation therapy tumor tracking.

Progress Towards Piezocomposite Transducers and Arrays for Real-time High Frequency Biomedical Ultrasound Imaging

In vivo ultrasound attenuation coefficient measurements are of interest as they can provide 1 ins... more In vivo ultrasound attenuation coefficient measurements are of interest as they can provide 1 insight into tissue pathology. They are also needed so that measurements of the tissue’s frequency 2 dependent ultrasound backscattering coefficient may be corrected for attenuation. In vivo 3 measurements of the attenuation coefficient are challenging because it has to be estimated from the 4 depth dependent decay of backscatter signals that display a large degree of magnitude variation. In this 5 study we describe and evaluate an improved backscatter method to estimate ultrasound attenuation 6 which is tolerant to the presence of some backscatter inhomogeneity. This employs an automated 7 algorithm to segment and remove atypically strong echoes to lessen the potential bias these may 8 introduce on the attenuation coefficient estimates. The benefit of the algorithm was evaluated by 9 measuring the frequency dependent attenuation coefficient of a gelatine phantom containing randomly 10 dist...

A Mask Based Ultrasound Array Design and Fabrication Process

No abstract available

LNCaP prostate cancer imaging with biologically functionalized gold nanoparticles in 2D and 3D cell culture

Anticancer Research, 2008

One of the main objectives of this project is to realize and validate a versatile lab system comp... more One of the main objectives of this project is to realize and validate a versatile lab system composed of functionalized nanoparticles for diagnosis of different superficial and accessible cancers, e.g. prostate cancer. Gold nanorods have been synthesized and functionalized with antibodies targeting specific antigens on cancer cell lines

Multi-band finite element simulation of ultrasound attenuation by soft tissue

2021 IEEE International Ultrasonics Symposium (IUS), 2021

The methods and results presented here test the ability of the multi-band finite element method t... more The methods and results presented here test the ability of the multi-band finite element method to simulate the frequency dependence of attenuation of ultrasound within soft tissue like materials, and the potential translation of the approach from its previous applications in non-destructive testing into medical ultrasound. Using a variety of materials, the approach was tested by comparing the theoretical attenuation (based on the input attenuation constants and path length through the materials) to the attenuation of the signal energy within the simulation. In two models, hypothetical materials were devised, with arbitrary attenuation properties and acoustic impedance matched to a background with the density and sound speed of water. In the third model, acoustic impedance mismatches were introduced to simulate the signal energy loss due to reflection and attenuation as an ultrasound beam passes from water into parallel layers of human skin, fat and muscle. In all cases, the calculated signal loss (from the reflection coefficients and attenuation constants) agreed with the signal loss measured within the simulation to a high degree, reproducing the input parameters to four significant figures in all cases.

Applied Sciences, 2021

Quantitative measures of radiation-induced breast stiffness are required to support clinical stud... more Quantitative measures of radiation-induced breast stiffness are required to support clinical studies of novel breast radiotherapy regimens and exploration of personalised therapy, however, variation between shear-wave elastography (SWE) machines may limit the usefulness of shear-wave speed (cs) for this purpose. Mean cs measured in four healthy volunteers’ breasts and a phantom using 2D-SWE machines Acuson S2000 (Siemens Medical Solutions) and Aixplorer (Supersonic Imagine) were compared. Shear-wave speed was measured in the skin region, subcutaneous adipose tissue and parenchyma. cs estimates were on average 2.3% greater when using the Aixplorer compared to S2000 in vitro. In vivo, cs estimates were on average 43.7%, 36.3% and 49.9% significantly greater (p << 0.01) when using the Aixplorer compared to S2000, for skin region, subcutaneous adipose tissue and parenchyma, respectively. In conclusion, despite relatively small differences between machines observed in vitro, large ...

Cancers, 2021

Background: ultrasound-based shear wave elastography (SWE) can non-invasively assess prostate tis... more Background: ultrasound-based shear wave elastography (SWE) can non-invasively assess prostate tissue stiffness. This systematic review aims to evaluate SWE for the detection of prostate cancer (PCa) and compare diagnostic estimates between studies reporting the detection of all PCa and clinically significant PCa (csPCa). Methods: a literature search was performed using the MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov, and CINAHL databases. Studies evaluating SWE for the detection of PCa using histopathology as reference standard were included. Results: 16 studies including 2277 patients were included for review. Nine studies evaluated SWE for the detection of PCa using systematic biopsy as a reference standard at the per-sample level, with a pooled sensitivity and specificity of 0.85 (95% CI = 0.74–0.92) and 0.85 (95% CI = 0.75–0.91), respectively. Five studies evaluated SWE for the detection of PCa using histopathology of radical prostatectomy (RP) specimens as the referen...

Ultrasonics, 2021

In vivo ultrasound attenuation coefficient measurements are of interest as they can provide insig... more In vivo ultrasound attenuation coefficient measurements are of interest as they can provide insight into tissue pathology. They are also needed so that measurements of the tissue's frequency dependent ultrasound backscattering coefficient may be corrected for attenuation. In vivo measurements of the attenuation coefficient are challenging because it has to be estimated from the depth dependent decay of backscatter signals that display a large degree of magnitude variation. In this study we describe and evaluate an improved backscatter method to estimate ultrasound attenuation which is tolerant to the presence of some backscatter inhomogeneity. This employs an automated algorithm to segment and remove atypically strong echoes to lessen the potential bias these may introduce on the attenuation coefficient estimates. The benefit of the algorithm was evaluated by measuring the frequency dependent attenuation coefficient of a gelatine phantom containing randomly distributed cellulose scatterers as a homogeneous backscattering component and planar pieces of cooked leek to provide backscattering inhomogeneities. In the phantom the segmentation algorithm was found to improve the accuracy and precision of attenuation coefficient estimates by up to 80% and 90%, respectively. The effect of the algorithm was then measured in vivo using 32 radiofrequency B-mode datasets from the breasts of two healthy female volunteers, producing a 5 to 25% reduction in mean attenuation coefficient estimates and a 30 to 50% reduction in standard deviation of attenuation coefficient across different positions within each breast. The results suggest that the segmentation algorithm may improve the accuracy and precision of attenuation coefficient estimates in vivo.

Photoacoustics, 2018

Epi-style optoacoustic (OA) imaging provides flexibility by integrating the irradiation optics an... more Epi-style optoacoustic (OA) imaging provides flexibility by integrating the irradiation optics and ultrasound receiver, yet clutter generated by optical absorption near the probe obscures deep OA sources. Localised vibration tagging (LOVIT) retrieves OA signal from images that are acquired with and without a preceding ultrasonic pushing beam: Radiation force leads to a phase shift of signals coming from the focal area resulting in their visibility in a difference image, whereas clutter from outside the pushing beam is eliminated. Disadvantages of a single-focus approach are residual clutter from inside the pushing beam above the focus, and time-intensive scanning of the focus to retrieve a large field-of-view. To speed up acquisition, we propose to create multiple foci in parallel, forming comb-shaped ARF patterns. By subtracting OA images obtained with interleaved combs, this technique moreover results in greatly improved clutter reduction in phantoms mimicking optical, acoustic an...

David Cosgrove

BMJ (Clinical research ed.), Aug 11, 2017