High-frequency ultrasonographic imaging of the gastrointestinal wall

Ødegaard, Svein; Nesje, L. B.; Lærum, Ole Didrik; Kimmey, Michael B.

doi:10.1586/erd.12.6

Cited by 32 publications

(40 citation statements)

References 56 publications

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“…The ability of µUS to characterize GI tissue with a high degree of agreement with histological analysis has been established (26,27). Part of the strong correlation between µUS images and histology stems from the ability of µUS to provide high resolution images, as noted in the previous section.…”

Section: Qualitative Aspectsmentioning

confidence: 95%

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Ultrasound capsule endoscopy: sounding out the future

Cox¹,

Stewart²,

Lay³

et al. 2017

Ann. Transl. Med.

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Video capsule endoscopy (VCE) has been of immense benefit in the diagnosis and management of gastrointestinal (GI) disorders since its introduction in 2001. However, it suffers from a number of well recognized deficiencies. Amongst these is the limited capability of white light imaging, which is restricted to analysis of the mucosal surface. Current capsule endoscopes are dependent on visual manifestation of disease and limited in regards to transmural imaging and detection of deeper pathology. Ultrasound capsule endoscopy (USCE) has the potential to overcome surface only imaging and provide transmural scans of the GI tract. The integration of high frequency microultrasound (µUS) into capsule endoscopy would allow high resolution transmural images and provide a means of both qualitative and quantitative assessment of the bowel wall. Quantitative ultrasound (QUS) can provide data in an objective and measurable manner, potentially reducing lengthy interpretation times by incorporation into an automated diagnostic process.The research described here is focused on the development of USCE and other complementary diagnostic and therapeutic modalities. Presently investigations have entered a preclinical phase with laboratory investigations running concurrently.

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Section: Qualitative Aspectsmentioning

confidence: 95%

“…Higher frequency sonography can depict bowel wall structure with additional details and layers (26,27,31). This additional detail makes µUS well suited for imaging the gut wall for subsurface and transmural defects.…”

Section: Qualitative Aspectsmentioning

confidence: 99%

Ultrasound capsule endoscopy: sounding out the future

Cox¹,

Stewart²,

Lay³

et al. 2017

Ann. Transl. Med.

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“…The layers of the human GIT are relatively thin (1 -2 mm) with respect to normal ultrasound (US) imaging wavelengths and frequencies [4], making US / µUS in the 15 -50 MHz range best suited for USCE applications. Previous work has shown that it can allow differentiation of the layers of the GIT [4] as well as quantitative analysis of diseased tissue [5].…”

Section: Microultrasound Transducersmentioning

confidence: 99%

“…Previous work has shown that it can allow differentiation of the layers of the GIT [4] as well as quantitative analysis of diseased tissue [5].…”

Section: Microultrasound Transducersmentioning

confidence: 99%

Progress towards a multi-modal capsule endoscopy device featuring microultrasound imaging

Lay

Qiu

Al-Rawhani

et al. 2016

2016 IEEE International Ultrasonics Symposium (IUS)

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Abstract-Current clinical standards for endoscopy in the gastrointestinal (GI) tract combine high definition optics and ultrasound imaging to view the lumen superficially and through its thickness. However, these instruments are limited to the length of an endoscope and the only clinically available, autonomous devices able to travel the full length of the GI tract easily offer only video capsule endoscopy (VCE). Our work seeks to overcome this limitation with a device ("Sonopill") for multimodal capsule endoscopy, providing optical and microultrasound (µUS) imaging and supporting sensors 1 . µUS transducers have been developed with multiple piezoelectric materials operating across a range of centre frequencies to study viability in the GI tract. Because of the combined constraints of µUS imaging and the low power / heat tolerance of autonomous devices, a hybrid approach has been taken to the transducer design, with separate transmit and receive arrays allowing multiple manufacturing approaches to maximise system efficiency. To explore these approaches fully, prototype devices have been developed with PVDF, highfrequency PZT and PMN-PT composites, and piezoelectric micromachined ultrasonic transducer arrays. Test capsules have been developed using 3D printing to investigate issues including power consumption, heat generation / dissipation, acoustic coupling, signal strength and capsule integrity. Because of the high functional density of the electronics in our proposed system, application specific integrated circuits (ASICs) have been developed to realise the ultrasound transmit and receive circuitry along with white-light and autofluorescence imaging with singlephoton avalanche detectors (SPADs).The ultrasound ASIC has been developed and the SPAD electronics and optical subsystem have been validated experimentally. The functionality of various transducer materials

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“…When imaging the wall of the GIT, it is clinically important to be able to distinguish the various layers and their characteristics for diagnostic purposes [2]. As the gut wall is relatively thin, minimizing depth-based signal attenuation, this makes capsule endoscopic ultrasound an ideal application for high-resolution ultrasonic imaging.…”

Section: Introductionmentioning

confidence: 99%

Design and simulation of a high-frequency ring-shaped linear array for capsule ultrasound endoscopy

Lay

Seetohul

Cox

et al. 2014

2014 IEEE International Ultrasonics Symposium

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Abstract-Current research into endoscopy and colonoscopy has significantly advanced visualization of the gastrointestinal tract (GIT). The Sonopill project seeks to combine the imaging capabilities of endoscopic ultrasound with the full GIT transit of capsule endoscopy through the development of a capsule capable of ultrasonic imaging of the GIT, focusing on the small intestine. However, due to the small volume of the proposed capsule and the need to transmit received data wirelessly, the Sonopill system is limited both in data bandwidth and power. This paper presents a MATLAB-based simulation to allow testing of transducer topologies and imaging methodologies to achieve optimum results within the physical limitations of the system. To allow rapid evaluation of possible transducer configurations and circuit elements, a hybrid MATLAB simulation was created, incorporating both KLM circuit elements for analog analysis and digitizing and beamforming elements to render a final grey-scale image for imaging quality analysis. This was used in conjunction with a theoretical acoustic propagation model to image ideal point scatterers.The proposed transducers consist of a single, unfocused transmit ring of radius 5 mm separated into eight segments for impedance control, and a 512-element receive linear array curved into a matching ring. Because of the high element count and pad limitations on the intended electronics, the design requires the use of 32 integrated 16:1 multiplexers which will be bonded directly to the connecting flex circuit before the ASIC. Simulating the loading effects of these multiplexers as well as the proposed transducer configuration was critical to the analysis of the design. The MATLAB model was used to simulate a standard pulser transmitting over a 2.5 m cable to a 0.25 mm x 8 mm x 85 µm PMN-PT piezocrystal transmit transducer with a centre frequency of 25 MHz. B-scan images were then modelled for three imaging phantoms, one containing three point target resolution phantoms, a resolution phantom containing two virtual walls, and a tissue mimicking phantom containing particles with two levels of reflectivity to represent a three layer gut phantom with a highreflectivity front surface.

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High-frequency ultrasonographic imaging of the gastrointestinal wall

Cited by 32 publications

References 56 publications

Ultrasound capsule endoscopy: sounding out the future

Ultrasound capsule endoscopy: sounding out the future

Progress towards a multi-modal capsule endoscopy device featuring microultrasound imaging

Design and simulation of a high-frequency ring-shaped linear array for capsule ultrasound endoscopy

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