Int J Colorectal Dis
October 2023
Purpose: Recently, recommendations on perioperative care have been published to optimize postoperative outcomes in preoperative patients with inflammatory bowel disease. This study evaluated the current use of preoperative screening and prehabilitation strategies (PS) prior to elective ileocolic resection (ICR) in patients with Crohn's disease (CD).
Methods: Patients with CD who underwent an elective ICR were identified from a Dutch prospective cohort study.
Aim: Colorectal surgery is associated with a high risk of adhesion formation and subsequent complications. Laparoscopic colorectal surgery reduces adhesion formation by 50%; however, the effect on adhesion-related complications is still unknown. This study aims to compare differences in incidence rates of adhesion-related readmissions after laparoscopic and open colorectal surgery.
View Article and Find Full Text PDFUltrasound imaging is used for detecting and characterizing breast lesions. A state of the art imaging method is the contrast source inversion (CSI), which solves the full wave nonlinear inverse problem. However, when the measurements are acquired in noisy environments, CSI can diverge from the correct solution after several iterations.
View Article and Find Full Text PDFIntravascular photoacoustic (IVPA) imaging can visualize the coronary atherosclerotic plaque composition on the basis of the optical absorption contrast. Most of the photoacoustic (PA) energy of human coronary plaque lipids was found to lie in the frequency band between 2 and 15 MHz requiring a very broadband transducer, especially if a combination with intravascular ultrasound is desired. We have developed a broadband polyvinylidene difluoride (PVDF) transducer (0.
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
April 2015
Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could be improved by taking advantage of advanced imaging algorithms, which become feasible for low frequencies if accurate knowledge about the phase and amplitude of the wave field illuminating the volume of interest is available. In this study, we compare five imaging and inversion methods: time-of-flight tomography, synthetic aperture focusing technique, backpropagation, Born inversion, and contrast source inversion.
View Article and Find Full Text PDF(Osteo)chondral defects (OCDs) in the ankle are currently diagnosed with modalities that are not convenient to use in long-term follow-ups. Ultrasound (US) imaging, which is a cost-effective and non-invasive alternative, has limited ability to discriminate OCDs. We aim to develop a new diagnostic technique based on US wave propagation through the ankle joint.
View Article and Find Full Text PDFNonlinear ultrasound is important in medical diagnostics because imaging of the higher harmonics improves resolution and reduces scattering artifacts. Second harmonic imaging is currently standard, and higher harmonic imaging is under investigation. The efficient development of novel imaging modalities and equipment requires accurate simulations of nonlinear wave fields in large volumes of realistic (lossy, inhomogeneous) media.
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
November 2012
Real-time 2-D or 3-D ultrasound imaging systems are currently used for medical diagnosis. To achieve the required data acquisition rate, these systems rely on parallel beamforming, i.e.
View Article and Find Full Text PDFRecently there has been growing interest in sensing by means of optical microring resonators in photonic integrated circuits that are fabricated in silicon-on-insulator (SOI) technology. Taillaert et al. [Proc.
View Article and Find Full Text PDFInt J Hyperthermia
December 2011
Purpose: High intensity focused ultrasound (HIFU) is used during hyperthermia cancer treatment to increase the tumour temperature. For an adequate and safe application it is important to measure the temperature in the heated region, preferably in a non-invasive manner and by the same modality as used for heating. The goal of this feasibility study is two-fold; first, it is investigated whether the acoustic non-linearity parameter B/A is most suitable for measuring temperature changes, second, a non-invasive thermometry method based on B/A is proposed and demonstrated.
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
May 2011
Simulations of acoustic wavefields in inhomogeneous media are always performed on finite numerical domains. If contrasts actually extend over the domain boundaries of the numerical volume, unwanted, non-physical reflections from the boundaries will occur. One technique to suppress these reflections is to attenuate them in a locally reflectionless absorbing boundary layer enclosing the spatial computational domain, a perfectly matched layer (PML).
View Article and Find Full Text PDFBackground: A frequently heard comment is that the current "Playstation generation" will have superior baseline psychomotor skills. However, research has provided inconsistent results on this matter. The purpose of this study was to investigate whether the "Playstation generation" shows superior baseline psychomotor skills for endoscopic surgery on a virtual reality simulator.
View Article and Find Full Text PDFBackground: Virtual reality (VR) simulators have been demonstrated to improve basic psychomotor skills in endoscopic surgery. The exercise configuration settings used for validation in studies published so far are default settings or are based on the personal choice of the tutors. The purpose of this study was to establish consensus on exercise configurations and on a validated training program for a virtual reality simulator, based on the experience of international experts to set criterion levels to construct a proficiency-based training program.
View Article and Find Full Text PDFObjective: The objective of the study was to validate virtual reality simulation in assessing laparoscopic skills in gynecology by establishing the extent of realism of the simulation to the actual task (face validity) and the degree to which the results of the test one uses reflects the subject tested (construct validity).
Study Design: Subjects (n = 56) were divided into 3 groups: novices (n = 15), intermediates (n = 20), and experts (n = 21). Participants completed 3 repetitions of a training program consisting of 4 basic skills and 3 gynecologic procedural simulations.
Imaging the two acoustic medium parameters density and compressibility requires the use of both the acoustic pressure and velocity wave fields, described via integral equations. Imaging is based on solving for the unknown medium parameters using known measured scattered wave fields, and it is difficult to solve this ill-posed inverse problem directly using a conjugate gradient inversion scheme. Here, a contrast source inversion method is used in which the contrast sources, defined via the product of changes in compressibility and density with the pressure and velocity wave fields, respectively, are computed iteratively.
View Article and Find Full Text PDFEmerging methods of hyperthermia cancer treatment require noninvasive temperature monitoring, and ultrasonic techniques show promise in this regard. Various tomographic algorithms are available that reconstruct sound speed or contrast profiles, which can be related to temperature distribution. The requirement of a high enough frequency for adequate spatial resolution and a low enough frequency for adequate tissue penetration is a difficult compromise.
View Article and Find Full Text PDF