National Research Council of Canada

Other

Coretech Medical Technologies Corporation

Henry H Mantsch

Michael G Sowa

Miroslaw F Stranc

Luis Oppenheimer

Mark Hewko

Kan-Zhi Liu

Michael Jackson

Lorenzo Leonardi

Anthony Shaw

Jan M Canvin

Michael G R Sowa

Hans H Eysel

Jing Wang

Jerl Payette

James R Mansfield

Bernhard J Schattka

Hani El-Gabalawy

Prolonged and severe tissue hypoxia results in tissue necrosis in pedicled flaps. We demonstrate the potential of near-infrared spectroscopy for predicting viability of compromised tissue portions. This approach clearly identifies tissue regions with low oxygen supply, and also the severity of this challenge, in a rapid and non-invasive manner, with a high degree of reproducibility. Early, nonsubjective detection of poor tissue oxygenation following surgery increases the likelihood that intervention aimed at saving the tissue will be successful.

Method for imaging variations in tissue viability

A non-invasive method of characterizing burn injuries using near infrared spectroscopy is described. In the method, a beam of light is emitted into the burnt tissue portion at two or more different tissue depths. The spectra are then compared using multivariate analysis to determine diagnostic regions of the spectra. This information is used to categorize the burn. In some cases, the diagnostic regions correspond to wavelengths related to the hemodynamics of the tissue portion. The spectra can also be repeated over time, thereby allowing trends and changes in the spectra to be measured. This data is in turn used to categorize the burn as either a superficial burn, partial thickness burn, deep partial burn or a full thickness burn. Once the burn has been categorized, the clinician can intervene as needed to treat the burn.

Visible-near infrared spectroscopy in burn injury assessment

Method of assessing tissue viability using near-infrared spectroscopy

A method of simultaneously determining the concentrations of cardiovascular risk markers selected from the group consisting of High Density Lipoprotein cholesterol (HDL-C), Low Density Lipoprotein cholesterol (LDL-C), total cholesterol, triglycerides and oxidized LDL using infra-red and/or near infrared light is described.

Method for the simultaneous and direct determination of serum cholesterol in high and low density lipoproteins using infrared spectroscopy

Prolonged and severe tissue hypoxia results in tissue necrosis in pedicled flaps. We demonstrate the potential of near-infrared spectroscopy for predicting viability of compromised tissue portions. This approach clearly identifies tissue regions with low oxygen supply, and also the severity of this challenge, in a rapid and non-invasive manner, with a high degree of reproducibility. Tissues remaining below a certain hemoglobin oxygen saturation threshold (oxygen saturation index<1) for prolonged periods (>6 h) became increasingly dehydrated, eventually becoming visibly necrotic. Tissues above this threshold (oxygen saturation index>1), despite being significantly hypoxic relative to the pre-elevation saturation values, remained viable over the 72 h post-elevation monitoring period. The magnitude of the drop in tissue oxygen saturation, as observed immediately following surgery, correlated with the final clinical outcome of the flap tissue. These results indicate the potential of near infrared spectroscopy and imaging to monitor tissue oxygenation status and assess tissue viability following reconstructive surgery. Early, nonsubjective detection of poor tissue oxygenation following surgery increases the likelihood that intervention aimed at saving the tissue will be successful.

A novel near infrared spectroscopic technique was used to characterize the joints in arthritis with comparison against normal joints. A beam of near infrared light was passed to joints through a fibre optic cable. Scattered light was collected by the same fibre bundle and a spectrum of the joint computed. Multivariate pattern recognition techniques identified regions of the spectrum which allowed discrimination between healthy and affected joints. Linear discriminant analysis resulted in correct classification of 74% of the joints. The high degree of similarity between mean spectra representing the early, late and control groups along with the significant between&mdash;subject variability in the data make diagnosis based on visual assessment of the spectra impossible. Linear discriminant analysis was therefore applied to spectra to determine if spectra could be classified by statistical methods as arising from early or late RA. Application of LDA resulted in correct classification of 74% of the joints. Interestingly, the spectral regions in which diagnostic differences were found by the multivariate analysis contain absorption bands related to tissue oxygenation status (oxy and deoxyhaemoglobin) and oxygen utilisation (cytochrome aa ), suggesting that ischaemic changes within the joint are being detected.

Diagnosis of rheumatoid arthritis in vivo using a novel spectroscopic approach

A spectrophotometric analytical method for lung permeability is described. An exogenous polydispersed macromolecule is administered, and fluid of the patient is evaluated using infrared spectroscopy.

Lung permeability analysis

Differences in the physical and chemical properties of synovial fluid from healthy and arthritic joints are detected by infrared spectroscopy. A beam of infrared light is directed at a sample of synovial fluid (either in its native form or prepared as a film) and changes in the physical and chemical properties of the fluid being analyzed are detected at one or more wavelengths to determine whether changes in the position, width, absolute intensity, relative intensity or shape of the infrared absorption have occurred which are characteristic of the arthritic condition.

Growing community of inventors

Berlin, Germany

Henry H Mantsch