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- Khodaverdi, Azin, et al.
(författare)
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The feasibility of using center frequency spectra in photoacoustic imaging for tissue characterization
- 2023
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Ingår i: IUS 2023 - IEEE International Ultrasonics Symposium, Proceedings. - 1948-5719 .- 1948-5727. - 9798350346459
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Konferensbidrag (refereegranskat)abstract
- In photoacoustic imaging, the amplitude of the photoacoustic signal is used for mapping the spatial distribution of a chromophore in the body and few studies have focused on the potential of using frequency content of the photoacoustic data. This study investigates the feasibility of using the photoacoustic center frequency spectrum in differentiating microspheres of various sizes and colors in phantoms. The microspheres with colors of green and blue, and the same size showed different center frequency spectrum shapes while keeping the offset (mean frequency) approximately the same. In addition, smaller microspheres showed higher center frequency offset, while larger microspheres showed smaller offset, suggesting the potential to use the center frequency spectrum for differentiating chromophores of various optical properties in the body.
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| 2. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Myocardial topical negative pressure increases blood flow in hypothermic, ischemic myocardium.
- 2008
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 42, s. 345-353
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Hypothermia protects the myocardium from oxidative injury during ischemic stress and reperfusion. We have previously shown that topical negative pressure (TNP) of -50 mmHg significantly increases microvascular blood flow in the underlying myocardium in normal, ischemic, and reperfused porcine myocardium. The present study was designed to elucidate the effect of TNP between -50 mmHg and -150 mmHg on microvascular blood flow in ischemic myocardium during hypothermia. Design. The microvascular blood flow in the myocardium was recorded, in seven pigs, using laser Doppler velocimetry. Analyses were performed in the epicardium and in the myocardium, after 40 minutes of occlusion of the LAD followed by cooling to 31 degrees C. Results. A TNP of -50 mmHg applied to the epicardium, from 23.3+/-3.8 PU to 104.2+/-31.3 PU (*p <0.05), and in the myocardium, from 35.0+/-7.2 PU to 74.2+/-21.8 PU (*p <0.05). Conclusions. Only a TNP level of -50 mmHg significantly increased the microvascular blood flow in both the epicardium and in the myocardium during hypothermia.
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| 7. |
- Alm, Rikard, et al.
(författare)
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Organ culture: a new model for vascular endothelium dysfunction.
- 2002
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Ingår i: BMC Cardiovascular Disorders. - 1471-2261. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Endothelium dysfunction is believed to play a role in the development of cardiovascular disease. The aim of the present study was to evaluate the suitability of organ culture as a model for endothelium dysfunction. METHODS: The isometric tension was recorded in isolated segments of the rat mesenteric artery branch, before and after organ culture for 20 h. Vasodilatation was expressed as % of preconstriction with U46619. The acetylcholine (ACh) induced nitric oxide (NO) mediated dilatation was studied in the presence of 10 &mgr;M indomethacin, 50 nM charybdotoxin and 1 &mgr;M apamin. Endothelium-derived hyperpolarising factor (EDHF) was studied in the presence of 0.1 mM L-NOARG and indomethacin. Prostaglandins were studied in the presence of L-NOARG, charybdotoxin and apamin. RESULTS: The ACh-induced NO and prostaglandin-mediated dilatations decreased significantly during organ culture (NO: 84% in control and 36% in cultured; prostaglandins: 48% in control and 16% in cultured). Notably, the total ACh-dilatation was not changed. This might be explained by the finding that EDHF alone stimulated a full dilatation even after organ culture (83% in control and 80% in cultured). EDHF may thereby compensate for the loss in NO and prostaglandin-mediated dilatation. Dilatations induced by forskolin or sodium nitroprusside did not change after organ culture, indicating intact smooth muscle cell function. CONCLUSIONS: Organ culture induces a loss in NO and prostaglandin-mediated dilatation, which is compensated for by EDHF. This shift in mediator profile resembles that in endothelium dysfunction. Organ culture provides an easily accessible model where the molecular changes that take place, when endothelium dysfunction is developed, can be examined over time.
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| 8. |
- Andersson, Emil, et al.
(författare)
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Facilitating clinically relevant skin tumor diagnostics with spectroscopy-driven machine learning
- 2024
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Ingår i: iScience. - 2589-0042. ; 27:5
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Tidskriftsartikel (refereegranskat)abstract
- In the dawning era of artificial intelligence (AI), health care stands to undergo a significant transformation with the increasing digitalization of patient data. Digital imaging, in particular, will serve as an important platform for AI to aid decision making and diagnostics. A growing number of studies demonstrate the potential of automatic pre-surgical skin tumor delineation, which could have tremendous impact on clinical practice. However, current methods rely on having ground truth images in which tumor borders are already identified, which is not clinically possible. We report a novel approach where hyperspectral images provide spectra from small regions representing healthy tissue and tumor, which are used to generate prediction maps using artificial neural networks (ANNs), after which a segmentation algorithm automatically identifies the tumor borders. This circumvents the need for ground truth images, since an ANN model is trained with data from each individual patient, representing a more clinically relevant approach.
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| 9. |
- Andreasson, Jesper, et al.
(författare)
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Exhaled phospholipid transfer protein and hepatocyte growth factor receptor in lung adenocarcinoma
- 2022
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Ingår i: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-9921 .- 1465-993X. ; 23:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Screening decreases mortality among lung cancer patients but is not widely implemented, thus there is an unmet need for an easily accessible non-invasive method to enable early diagnosis. Particles in exhaled air offer a promising such diagnostic tool. We investigated the validity of a particles in exhaled air device (PExA) to measure the particle flow rate (PFR) and collect exhaled breath particles (EBP) to diagnose primary lung adenocarcinoma (LUAD).METHODS: Seventeen patients listed for resection of LUAD stages IA-IIIA and 18 non-cancer surgical control patients were enrolled. EBP were collected before and after surgery for LUAD, and once for controls. Proteomic analysis was carried out using a proximity extension assay technology. Results were validated in both plasma from the same cohort and with microarray data from healthy lung tissue and LUAD tissue in the GSE10072 dataset.RESULTS: Of the 92 proteins analyzed, levels of five proteins in EBP were significantly higher in the LUAD patients compared to controls. Levels of phospholipid transfer protein (PLTP) and hepatocyte growth factor receptor (MET) decreased in LUAD patients after surgery compared to control patients. PFR was significantly higher in the LUAD cohort at all timepoints compared to the control group. MET in plasma correlated significantly with MET in EBP.CONCLUSION: Collection of EBP and measuring of PFR has never been performed in patients with LUAD. In the present study PFR alone could distinguish between LUAD and patients without LUAD. PLTP and MET were identified as potential biomarkers to evaluate successful tumor excision.
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| 10. |
- Anesater, Erik, et al.
(författare)
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A Rigid Disc for Protection of Exposed Blood Vessels During Negative Pressure Wound Therapy
- 2013
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Ingår i: Surgical Innovation. - : SAGE Publications. - 1553-3506 .- 1553-3514. ; 20:1, s. 74-80
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Tidskriftsartikel (refereegranskat)abstract
- Background. There are increasing reports of serious complications and deaths associated with negative pressure wound therapy (NPWT). Bleeding may occur when NPWT is applied to a wound with exposed blood vessels. Inserting a rigid disc in the wound may protect these structures. The authors examined the effects of rigid discs on wound bed tissue pressure and blood flow through a large blood vessel in the wound bed during NPWT. Methods. Wounds were created over the femoral artery in the groin of 8 pigs. Rigid discs were inserted. Wound bed pressures and arterial blood flow were measured during NPWT. Results. Pressure transduction to the wound bed was similar for control wounds and wounds with discs. Blood flow through the femoral artery decreased in control wounds. When a disc was inserted, the blood flow was restored. Conclusions. NPWT causes hypoperfusion in the wound bed tissue, presumably as a result of mechanical deformation. The insertion of a rigid barrier alleviates this effect and restores blood flow.
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