| 1. |
- Bengtsson, Alexander, et al.
(författare)
-
Characterization and modeling of acousto-optic signal strengths in highly scattering media
- 2019
-
Ingår i: Biomedical Optics Express. - 2156-7085. ; 10:11, s. 5565-5584
-
Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is an imaging technique based on the acousto-optic effect that can perform optical imaging with ultrasound resolution inside turbid media, and is thus interesting for biomedical applications, e.g. for assessing tissue blood oxygenation. In this paper, we present near background free measurements of UOT signal strengths using slow light filter signal detection. We carefully analyze each part of our experimental setup and match measured signal strengths with calculations based on diffusion theory. This agreement between experiment and theory allows us to assert the deep tissue imaging potential of similar to 5 cm for UOT of real human tissues predicted by previous theoretical studies [Biomed. Opt. Express 8, 4523 (2017)] with greater confidence, and indicate that future theoretical analysis of optimized UOT systems can be expected to be reliable. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
|
|
| 2. |
- Chaudhry, Nadia, et al.
(författare)
-
Breast Cancer Diagnosis Using Extended-Wavelength–Diffuse Reflectance Spectroscopy (EW-DRS) : Proof of Concept in Ex Vivo Breast Specimens Using Machine Learning
- 2023
-
Ingår i: Diagnostics. - 2075-4418. ; 13:19, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- This study aims to investigate the feasibility of using diffuse reflectance spectroscopy (DRS) to distinguish malignant breast tissue from adjacent healthy tissue, and to evaluate if an extended-wavelength range (450–1550 nm) has an advantage over the standard wavelength range (450–900 nm). Multivariate statistics and machine learning algorithms, either linear discriminant analysis (LDA) or support vector machine (SVM) are used to distinguish the two tissue types in breast specimens (total or partial mastectomy) from 23 female patients with primary breast cancer. EW-DRS has a sensitivity of 94% and specificity of 91% as compared to a sensitivity of 40% and specificity of 71% using the standard wavelength range. The results suggest that DRS can discriminate between malignant and healthy breast tissue, with improved outcomes using an extended wavelength. It is also possible to construct a simple analytical model to improve the diagnostic performance of the DRS technique.
|
|
| 3. |
- Cinthio, Magnus, et al.
(författare)
-
Estimation of arterial pulse wave velocity with a new improved tissue Doppler method
- 2001
-
Ingår i: 2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society. - 0780372115 ; , s. 188-191
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The mechanical properties of the large arteries are important determinants in the circulation physiology. Quantities associated with vessel wall elasticity are of particular interest since they offer a possibility to separate diseased arteries from healthy. Pulse wave velocity (PWV) is a local measure of the arterial wall elasticity. This paper describes a new improved method for non-invasive local PWV estimation. The PWV estimation is based on arterial wall movements, which is detected by Tissue Doppler Imaging (TDI), a color Doppler optimized for low velocities. The TDI facility allows the artery to be measured at several positions simultaneously, which improves the PWV estimation considerably. The method is validated with respect to operator repeatability and operator reproducibility in a limited clinical study.
|
|
| 4. |
- Cinthio, Magnus, et al.
(författare)
-
Intra-Observer Variability of Longitudinal Movement and Intramural Shear Strain Measurements of the Arterial Wall using Ultrasound Non-Invasively in vivo
- 2010
-
Ingår i: Ultrasound in Medicine and Biology. - : Elsevier BV. - 0301-5629. ; 36:5, s. 697-704
-
Tidskriftsartikel (refereegranskat)abstract
- Using a recently developed high-resolution noninvasive ultrasonic method, we recently demonstrated that the intima-media complex of the common carotid artery show a bidirectional multiphasic longitudinal displacement of the same magnitude as the diameter change during the cardiac cycle. The longitudinal movement of the adventitial region was smaller, thus, we identified shear strain and, thus, shear stress, within the arterial wall. The aim of this study was to evaluate the intra-observer variability of measurement of the longitudinal displacement of the intima-media complex and the intramural shear strain of the common carotid artery in vivo using the new ultrasonic method. The evaluation was carried out by comparing two consecutive measurements on the common carotid artery of 20 healthy human subjects. According to the method of Bland Altman, we show that the systematic and random differences for the different phases of movement are acceptable in comparison to the measured displacement and no significant differences between the two measurements could be detected (p > 0.05 for all measured parameters). The coefficient of variation (CV) for measurement of the different phases of movement was ≤16%, including short-term physiologic variations. The higher variability in the measurement of the intramural shear strain (CV = 24%) has several explanations, which are discussed. In conclusion, this study shows that the present first ultrasonic method for high-resolution measurement of the longitudinal movement of the arterial wall is reliable and satisfactory for the further research of the longitudinal movement of the arterial wall in vivo. Further studies on the longitudinal movement of the arterial wall are important for developing an improved understanding of the physiology and the pathophysiology of the cardiovascular system.
|
|
| 5. |
|
|
| 6. |
- Cinthio, Magnus, et al.
(författare)
-
New Approaches in Arterial Characterisation
- 2008
-
Ingår i: Proceedings of 11th International Symposium on Advanced Biomedical Ultrasound (Invited). ; , s. 3-8
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- —The aim of this paper is to briefly present the historyand the status of the arterial characterization of today as wellas summarize our work on two new approaches in arterialcharacterization – measurements of the longitudinal movementand the minute roughness of the arterial wall.
|
|
| 7. |
- Cinthio, Magnus, et al.
(författare)
-
New improved and modified method for measurements of arterial wall movements in longitudinal and radial directions
- 2005
-
Ingår i: Medical physics : proceedings of the jointly held congresses ICMP 2005, 14th International Conference of the Medical Physics of the International Organization for Medical Physics (IOMP), the European Federation of Organisations in Medical Physics (EFOMP) and the German Society of Medical Physics (DGMP) [and] BMT 2005, 39th annual congress of the German Society for Biomedical Engineering (DGBMT) ; 14th - 17th September 2005, Nuremberg, Germany. ; 50, s. 869-870
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 8. |
|
|
| 9. |
- Hill, David, et al.
(författare)
-
Acousto-optic interaction strengths in optically scattering media using high pressure acoustic pulses
- 2021
-
Ingår i: Biomedical Optics Express. - 2156-7085. ; 12:6, s. 3196-3213
-
Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is a developing medical imaging technique with the potential to noninvasively image tissue oxygenation at depths of several centimeters in human tissue. To accurately model the UOT imaging, it is necessary the calculate the signal produced by the interaction between ultrasound and light in the scattering medium. In this paper we present a rigorous description for modeling this process for ultrasound pulses in the non-linear regime with peak pressures ranging up to the medical safety limit. Simulation results based on the presented model agree well with measurements performed with fully characterized ultrasound pulses. Our results also indicate that the UOT modeling process can be accurately simplified by disregarding the acoustically induced movement of scatterers. Our results suggest that the explored model and its software implementation can be used as a virtual lab to aid future development of pulses and UOT imaging algorithms.
|
|
| 10. |
- Hult, Jenny, et al.
(författare)
-
Unique spectral signature of human cutaneous squamous cell carcinoma by photoacoustic imaging
- 2020
-
Ingår i: Journal of Biophotonics. - : Wiley. - 1864-063X .- 1864-0648. ; 13:5
-
Tidskriftsartikel (refereegranskat)abstract
- Cutaneous squamous cell carcinoma (cSCC) is a common skin cancer with metastatic potential. To reduce reoperations due to nonradical excision, there is a need to develop a technique for identification of tumor margins preoperatively. Photoacoustic (PA) imaging is a novel imaging technology that combines the strengths of laser optics and ultrasound. Our aim was to determine the spectral signature of cSCC using PA imaging and to use this signature to visualize tumor architecture and borders. Two-dimensional PA images of 33 cSCCs and surrounding healthy skin were acquired ex vivo, using 59 excitation wavelengths from 680 to 970 nm. The spectral response of the cSCCs was compared to healthy tissue, and the difference was found to be greatest at wavelengths in the range 765 to 960 nm (P <.05). Three-dimensional PA images were constructed from spectra obtained in the y-z plane using a linear stepper motor moving along the x-plane. Spectral unmixing was then performed which provided a clear three-dimensional view of the distribution of tumor masses and their borders.
|
|
