US3741198A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiological diagnostic method
Assignee: Temple University
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Filing: 1971-10-12
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Granted: 1973-06-26
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Expires: 1991-10-12
Abstract
Abstract A radiological diagnostic method is provided in which a radiopaque ferrofluid is injected into a body system which is to be studied, such as the subarachnoid space surrounding the spinal cord. The ferrofluid is then transferred through the body system by applying a magnetic force to the ferrofluid. The portions of the body system of particular interest are radiographicly or fluoroscopicly examined while the ferrofluid is present in these areas. The ferrofluid is thereafter removed by drawing it back to the point of introduction and removing it from the body system. The diagnostic method of this invention is especially useful in myelographic studies.
Inventors
- 👤 C Burton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:54
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/48; A61B6/481; A61B5/00; A61B5/06; A61B6/50; A61B6/506
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
135 words
The method for radiologically examining a body system having an internal area which contains a fluid which is relatively static or which has a mucous lining, said method comprising inserting into said area a given amount of a radiopaque ferrofluid comprised of ferromagnetic domain particles having a diameter of from about 10-300 A which are enveloped with a physiologically inert liquid carrier which is insoluble and immiscible with said fluid and mucous, said given amount being an amount sufficient to provide an effective contrast in radiopaqueness for a radiological examination; radiological examining said body system, and thereaFter removing said ferrofluid from said body system by applying a magnetic force to an extraction means inserted into said area sufficient to magnetically attract said ferrofluid to said extraction means and withdrawing said ferrofluid with said extraction means.
Claim 2
Independent Claim
135 words
The method for radiologically examining a body system having an internal area which contains a fluid which is relatively static or which has a mucous lining, said method comprising inserting into said area a given amount of a radiopaque ferrofluid comprised of ferromagnetic domain particles having a diameter of from about 10-300 A which are enveloped with a physiologically inert liquid carrier which is insoluble and immiscible with said fluid and mucous, said given amount being an amount sufficient to provide an effective contrast in radiopaqueness for a radiological examination; radiological examining said body system, and thereaFter removing said ferrofluid from said body system by applying a magnetic force to an extraction means inserted into said area sufficient to magnetically attract said ferrofluid to said extraction means and withdrawing said ferrofluid with said extraction means.
Claim 3
Dependent Claim
45 words
The method according to claim 1 wherein the amount of ferrofluid inserted is less than the volume of the area and wherein the ferrofluid is moved from the point of introduction to a portion of said area by applying a magnetic force to said ferrofluid.
Claim 4
Dependent Claim
21 words
The method according to claim 1 wherein the amount of magnetic force delivered to said ferrofluid is from about 5,000-10,000 Gauss.
Claim 5
Dependent Claim
38 words
The method according to claim 1 wherein said magnetic force is provided by a permanent magnet comprised of a member selected from the group consisting of a rare earth metal, nickel, cobalt, alloys thereof and alloys with aluminum.
Claim 6
Dependent Claim
13 words
The method according to claim 4 wherein said magnet is a samarium-cobalt magnet.
Claim 7
Dependent Claim
16 words
The method according to claim 1 wherein said liquid carrier is a fluorinated lower aliphatic hydrocarbon.
Claim 8
Dependent Claim
102 words
The method according to claim 1 for radiological examining of the spinal column comprising the steps of inserting a lumbar puncture needle into the subarachnoid space; injecting said given amount of said ferrofluid through said lumbar puncture needle into the subarachnoid space; moving said ferrofluid from the point of insertion through the subarachnoid space by applying a magnetic force of about 5,000-10,000 Gauss to said ferrofluid to transfer said ferrofluid to a section of said area to be radiologically studied; radiologically examining said section; thereafter moving said ferrofluid back to the point of insertion and withdrawing it through said lumbar puncture needle.
Claim 9
Dependent Claim
19 words
The method according to claim 7 wherein the ferrofluid is injected into the subarachnoid space surrounding the cauda equina.
Claim 10
Dependent Claim
38 words
The method according to claim 7 wherein the magnetic force is provided by a permanent magnet made of a member selected from the group consisting of a rare earth metal, nickel, cobalt, alloys thereof and alloys with aluminum.
Claim 11
Dependent Claim
13 words
The method according to claim 9 wherein the magnet is a samarium-cobalt magnet.
Claim 12
Dependent Claim
116 words
The method according to claim 7 wherein the lumbar puncture needle has a given ID, a given length and a sharpened bevel at a terminal end thereof, within which an insert needle made of a magnetizable metal having an OD less than said given ID, a length greater than said given length, and a smooth, round, perforated tip is inserted after insertion of the lumbar puncture needle, into the subarachnoid space with tip of the insert needle extending past the bevel of the lumbar puncture needle and thereafter the insert needle is magnetized to attract the ferrofluid to the tip of the insert needle through which the ferrofluid is removed after completion of the radiological examination.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |