EP0130479A2
Expired / Lapsed
EP
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Method of projection reconstruction imaging with reduced sensitivity to motion-related artifacts
Assignee: General Electric Co
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Filing: 1984-06-20
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Granted: —
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Expires: 2004-06-20
Abstract
Abstract A method is provided for imaging a transverse slice of an object with reduced sensitivity to image artifacts due to object motion during the scan. The method utilizes projection measurements corresponding to at least a 180°C scan of the slice. The measurements are taken sequentially for views that are adjacent in angle such that measurements which are at the extremes of the scan angle are nevertheless measured at points close in time, reducing inconsistencies therebetween. The method is applicable to a number of modalities utilizing parallel-ray and fan-beam geometries, such as NMR and ultrasound, respectively.
Inventors
- 👤 Norbert Joseph Pelc
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 10:49
CPC Classifications
A; A61; A61B; A61B8/00; A61B8/13; A61B8/15; G; G01; G01N; G01N24/00; G01N24/08; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/44; G01R33/48; G01R33/54; G01S; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01R33/56; G01R33/565; G01R33/56509
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
81 words
In a method of imaging a slice in an object undergoing examination, which method utilizes a plurality of projection measurements corresponding to at least a 180° scan of said slice, the improvement wherein the pair of projection measurements at opposite angular extremes of said scan are taken successively close in time so as to reduce inconsistencies therebetween, remaining ones of said plurality of projection measurements being taken in an oscillatory manner in time for projection angles between said opposite scan extremes.
Claim 2
Dependent Claim
81 words
In a method of imaging a slice in an object undergoing examination, which method utilizes a plurality of projection measurements corresponding to at least a 180° scan of said slice, the improvement wherein the pair of projection measurements at opposite angular extremes of said scan are taken successively close in time so as to reduce inconsistencies therebetween, remaining ones of said plurality of projection measurements being taken in an oscillatory manner in time for projection angles between said opposite scan extremes.
Claim 3
Dependent Claim
48 words
The method of Claim 1 wherein said pair of projection measurements at the angular extremes of said scan comprise the temporal beginning of said scan, and wherein the remaining of said plurality of measurements are taken in an oscillatory measuring sequence toward the angular center of the scan.
Claim 4
Independent Claim
50 words
The method of Claim I wherein said pair of projection measurements comprise the temporal end of said scan, and wherein the remaining of said plurality of measurements are taken in an oscillatory measuring sequence beginning with measurements in an angularly central region of said scan toward the two angular extremes.
Claim 5
Dependent Claim
12 words
The method of Claim 1 wherein said method comprises measuring parallel-ray projections.
Claim 6
Dependent Claim
25 words
The method of Claim 4 wherein the direction of each projection measurement within said imaging slice is determined by the direction of a magnetic-field gradient.
Claim 7
Dependent Claim
72 words
The method of Claim 5 wherein said imaging slice is positioned in a static homogeneous magnetic field and includes the steps of: selectively exciting a plurality of nuclear spins situated in said imaging slice such that said nuclear spins produce an NMR signal; and observing said NMR signal in the presence of said magnetic-field gradient wherein isochromats perpendicular to the gradient direction represent projections of points along the isochromats onto said gradient.
Claim 8
Dependent Claim
12 words
The method of Claim 1 wherein said method comprises measuring fan-beam projections.
Claim 9
Dependent Claim
15 words
The method of Claim 7 wherein said fan beam comprises a beam of ultrasonic energy.
Claim 10
Dependent Claim
35 words
The method of Claim 8 wherein said projection measurements comprise measuring the intensity of the ultrasonic energy not absorbed or scattered within said imaging slice along a plurality of ray paths within said fan beam.
Claim 11
Dependent Claim
28 words
The method of Claim 8 wherein said projection measurements comprise measuring the propagation velocity of said ultrasonic beam along a plurality of ray paths within said fan beam.
Claim 12
Dependent Claim
22 words
The method of Claim 8 wherein projection measurements are made to corespond to at least a 360 0 scan of the object.
Claim 13
Dependent Claim
78 words
The method of Claim 8 wherein said step of measuring a projection comprises the steps of: positioning said object in an annular array of ultrasonic transducers each capable of transmitting and receiving ultrasonic energy; irradiating said imaging slice with a substantially coplanar beam of ultrasonic energy produced by one of said transducers; and detecting the ultrasonic energy not attenuated or scattered within said slice at a plurality of transducers situated within an angle subtended by said fan beam.
References Cited (Backward Citations)
No citation records indexed.
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