This paper presents an evaluation of a prototype diffuse optical tomography (DOT) system. Seventeen women with 18 breast lesions (10 invasive carcinomas, 2 fibroadenomas, and 6 benign cysts; diameters 13-54 mm) were evaluated with DOT and magnetic resonance imaging (MRI). A substantial fraction of the original 36 recruited patients could not be examined using this prototype due to technical problems. A region of interest (ROI) was drawn at the lesion position as derived from MRI and at the mirror image site in the contralateral healthy breast. ROIs were assessed quantitatively and qualitatively by two observers independently in two separate readings. Intra- and interobserver agreements were calculated using kappa statistics (k) and intraclass correlation coefficients (ICCs). Discriminatory values for presence of malignancy were determined by receiver operating characteristic (ROC) analyses. Intraobserver agreements were excellent (k 0.88 and 0.88; ICC 0.978 and 0.987), interobserver agreements were good to excellent (k 0.77-0.95; ICC 0.96-0.98). Discriminatory values for presence of malignancy were 0.92-0.93 and 0.97-0.99 for quantitative and qualitative ROC analysis, respectively. This DOT system has the potential to discriminate malignant from benign breast tissue in a reproducible qualitative and quantitative manner. Important technical improvements are required before this technique is ready for clinical application.
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http://dx.doi.org/10.1007/s00330-008-1268-3 | DOI Listing |
Photochem Photobiol
December 2024
Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil.
Given that non-equilibrium molecular motion in thermal gradients is influenced by both solute and solvent, the application of spectroscopic methods that probe each component in a binary mixture can provide insights into the molecular mechanisms of thermal diffusion for a large class of systems. In the present work, we use an all-optical setup whereby near-infrared excitation of the solvent leads to a steady-state thermal gradient in solution, followed by characterization of the non-equilibrium system with electronic spectroscopy, imaging, and intensity. Using rhodamine B in water as a case study, we perform measurements as a function of solute concentration, temperature, wavelength, time, near-infrared laser power, visible excitation wavelength, and isotope effect.
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November 2024
Anesthesiology and Pain Medicine, Harborview Medical Center, Seattle, USA.
Prompt emergence from general anesthesia is crucial after neurosurgical procedures, such as craniotomies, to facilitate timely neurological evaluation for identification of intraoperative complications. Delayed emergence can be caused by residual anesthetics, metabolic imbalances, and intracranial pathology, for which an eye examination can provide early diagnostic clues. The sunset sign (or setting sun sign), characterized by a downward deviation of the eyes, can be an early indicator of raised intracranial pressure (ICP) or midbrain compression, as is commonly observed in states of hydrocephalus or periaqueductal or tectal plate dysfunction.
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November 2024
Dermatology, Maharishi Markandeshwar Institute of Medical Sciences and Research, Ambala, IND.
Background Topical steroid-dependent or damaged face (TSDF) is a common condition where the widespread availability of over-the-counter topical corticosteroid (TCS)-containing products leads to their misuse and addiction. Prolonged use of these steroids on the face can result in significant side effects. Early diagnosis and cessation of steroid use are important.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA.
We propose an overview of the Rytov approximation in diffuse optics of biological tissues, for the inverse and forward problems. First, we show a physical interpretation of the Rytov approximation as a type of partial pathlength (named fluence rate partial pathlength) which is distinct from the usual partial pathlength for reflectance measurements. Second, we study the accuracy of the Rytov approximation for the calculation of Jacobians considering absorption perturbations and reflectance measurements.
View Article and Find Full Text PDFNeuroimage
December 2024
Institute of Population Health, University of Liverpool, United Kingdom; Hanse Wissenschaftskolleg, Delmenhorst, Germany. Electronic address:
Recent work has shown rapid microstructural brain changes in response to learning new tasks. These cognitive tasks tend to draw on multiple brain regions connected by white matter (WM) tracts. Therefore, behavioural performance change is likely to be the result of microstructural, functional activation, and connectivity changes in extended neural networks.
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