Patent US4867165A successfully refreshed from Google Patents.
US4867165A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for determining the perfusion
Assignee: HAIR ART Inc
•
Filing: 1987-08-13
•
Granted: 1989-09-19
•
Expires: 2007-08-13
Abstract
Abstract A method is proposed for determining the perfusion by evaluation of the light emitted by at least one light source and influenced by the arterial blood, by use of optical measuring means which measure the intensity variation as a consequence of the variation in arterial blood volume. According to this method, the perfusion is either displayed as variation in thickness from the sum of the parallel tissue enlargements d or as normalized volume. The perfusion is derived by one or more measurements of light intensity. According to the invention, for the first time a method for determining perfusion as a quantitative value is provided.
Inventors
- 👤 Friedemann Noller
- 👤 Klaus Forstner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:59
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/68; A61B5/6801; A61B5/6813; A61B5/6825; A61B5/6826; A61B5/02; A61B5/026; A61B5/0261; A61B5/145; A61B5/1455; A61B5/14551; A61B5/683; A61B5/6838; A61B5/14552
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
65 words
A method for determining the perfusion of blood in a body member comprising: passing light having the isobestic wavelength through a member of the body, measuring the variation, in intensity, ΔI, of light emerging from said body member due to arterial blood volume variation, and deriving from ΔI one of the variations in thickness, Δd/d, of the body member or the variation in volume ΔV/V.
Claim 2
Independent Claim
65 words
A method for determining the perfusion of blood in a body member comprising: passing light having the isobestic wavelength through a member of the body, measuring the variation, in intensity, ΔI, of light emerging from said body member due to arterial blood volume variation, and deriving from ΔI one of the variations in thickness, Δd/d, of the body member or the variation in volume ΔV/V.
Claim 3
Dependent Claim
102 words
A method according to claim 1 wherein the light intensity variation (ΔI) is converted into a current variation by optoelectronic means and is determined as relative variation in current (ΔI/Imax), and that the perfusion thickness Δd or the normalized perfusion ΔV/V is determined by a substitution of the known determined quantities in: ##EQU5## ΔI/Imax being the relative variation in intensity at the isobestic wavelength λ i , c 1 to c n being the molecular concentrations of hemoglobin, oxihemoglobin or other substances, E 1i to E ni being the extinction coefficients for hemoglobin, oxihemoglobin or other substances at wavelength λ i .
Claim 4
Dependent Claim
48 words
A method according to claim 2 characterized in that measurements of the relative intensity variation (ΔI/Imax) are carried out at a number of different wavelengths and that these measurements are used to determine a corresponding number of unknown equation parameters such as hemoglobin concentration, oxygen saturation and perfusion.
Claim 5
Independent Claim
72 words
A method for determining the perfusion of blood in a body member comprising: passing light, of two different wavelengths which both differ from the isobestic wavelength, through a member of the body; measuring the variation in intensity, ΔI, of light emerging from said body member due to arterial blood volume variation; and deriving from ΔI one of the variations in thickness, Δd/d, of the body member or the variation in volume ΔV/V.
Claim 6
Independent Claim
72 words
A method for determining the perfusion of blood in a body member comprising: passing light, of two different wavelengths which both differ from the isobestic wavelength, through a member of the body; measuring the variation in intensity, ΔI, of light emerging from said body member due to arterial blood volume variation; and deriving from ΔI one of the variations in thickness, Δd/d, of the body member or the variation in volume ΔV/V.
References Cited (Backward Citations)
US3496373A
Cited
US3545430A
Cited
US3732016A
Cited
US4109643A
Cited
US4167331A
Cited
US4407290A
Cited
US4407290B1
Cited
WO1986005674A1
Cited
JPS628004A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |