US4779619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
23 NA magnetic resonance functional brain imaging
Assignee: Wisconsin Alumni Research Foundation
•
Filing: 1986-08-15
•
Granted: 1988-10-25
•
Expires: 2006-08-15
Abstract
Abstract Magnetic resonance imaging of sodium levels in the brain is used as a method for determining regional brain function. Direct measurement of sodium levels can be directly used to determine characteristics of blood volume in the cerebrum for research, diagnostic or clinical applications. Determination of the ratio between changes in sodium level changes and changes in arterial dissolved carbon dioxide levels can be used as a measure of regional vascular reserve when compared with norms, as an early indicator of possible cerebral ischemia. Grey scale images can be made by tomographic methods of the information generated by these scans.
Inventors
- 👤 Stefan S. Winkler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:43
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/5601; A; A61; A61B; A61B5/00; A61B5/05; A61B5/055; G01R33/46; G01R33/465; G01R33/4806
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
45 words
A method of monitoring changes in regional cerebral blood volume in a patient comprising the steps of measuring 23 Na changes in the patient's cerebrum by a magnetic resonance scanning and using the measured changes as an indication of changes in regional cerebral blood volume.
Claim 2
Independent Claim
45 words
A method of monitoring changes in regional cerebral blood volume in a patient comprising the steps of measuring 23 Na changes in the patient's cerebrum by a magnetic resonance scanning and using the measured changes as an indication of changes in regional cerebral blood volume.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 1 wherein the 23 Na level is monitored as CO 2 is introduced into the patient's respiratory gases.
Claim 4
Dependent Claim
23 words
A method as claimed in claim 2 further including the step of simultaneously testing the dissolved CO 2 level in the patient's blood.
Claim 5
Dependent Claim
32 words
A method as claimed in claim 1 further including creating a grey-scale image wherein each voxel is shaded by a grey scale value proportional to the difference between measured 23 Na levels.
Claim 6
Dependent Claim
36 words
A method as claimed in claim 1 further including comparing the measured 23 Na levels to norms developed for the patient's age, sex, blood pressure, hematocrit and serum sodium values to determine relative regional brain function.
Claim 7
Independent Claim
108 words
A method of testing for regional vascular reserve in a patient's cerebrum comprising the steps of conducting a first magnetic resonance scan of 23 Na in the patient's cerebrum to obtain baseline 23 Na information; introducing a physiologically significant level of carbon dioxide into the patient's respiratory gases; conducting a second magnetic resonance scan of 23 Na in the patient's cerebrum; simultaneously monitoring the level of dissolved carbon dioxide in the patient's blood; and calculating the ratio of change in scanned 23 Na level to the change in blood carbon dioxide level caused by the carbon dioxide in the respiratory gases as an index of regional vascular reserve.
Claim 8
Independent Claim
108 words
A method of testing for regional vascular reserve in a patient's cerebrum comprising the steps of conducting a first magnetic resonance scan of 23 Na in the patient's cerebrum to obtain baseline 23 Na information; introducing a physiologically significant level of carbon dioxide into the patient's respiratory gases; conducting a second magnetic resonance scan of 23 Na in the patient's cerebrum; simultaneously monitoring the level of dissolved carbon dioxide in the patient's blood; and calculating the ratio of change in scanned 23 Na level to the change in blood carbon dioxide level caused by the carbon dioxide in the respiratory gases as an index of regional vascular reserve.
Claim 9
Dependent Claim
33 words
A method as claimed in claim 6 further including displaying the ratios derived on a grey scale for each voxel of brain scan area to create a pictorial image of regional vascular reserve.
Claim 10
Dependent Claim
23 words
A method as claimed in claim 6 wherein the level of carbon dioxide is between about 5% and 10% of inspired respiratory gases.
Claim 11
Dependent Claim
34 words
A method as claimed in claim 6 further including comparing the calculated ratio to norms developed for the patient's age, sex, blood pressure, hematocrit, and serum sodium values to determine relative regional vascular reserve.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |