Source: http://www.google.com/patents/US6556697?dq=3984803
Timestamp: 2014-07-11 03:33:42
Document Index: 4693144

Matched Legal Cases: ['art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9', 'art 9']

Patent US6556697 - Image reconstruction method - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsIn an image reconstruction method for imaging a periodically moving object with a computed tomography apparatus employing a multi-line detector unit, suitable selection of the rotational speed of the carrier of the computed tomography apparatus and employment of a three-dimensional back-projection algorithm,...http://www.google.com/patents/US6556697?utm_source=gb-gplus-sharePatent US6556697 - Image reconstruction methodAdvanced Patent SearchPublication numberUS6556697 B1Publication typeGrantApplication numberUS 09/396,337Publication dateApr 29, 2003Filing dateSep 15, 1999Priority dateSep 15, 1998Fee statusPaidPublication number09396337, 396337, US 6556697 B1, US 6556697B1, US-B1-6556697, US6556697 B1, US6556697B1InventorsHerbert Bruder, Thomas Flohr, Bernd Ohnesorge, Stefan Schaller, Bernhard ScholzOriginal AssigneeSiemens AktiengesellschaftExport CitationBiBTeX, EndNote, RefManPatent Citations (15), Referenced by (15), Classifications (16), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetImage reconstruction methodUS 6556697 B1Abstract In an image reconstruction method for imaging a periodically moving object with a computed tomography apparatus employing a multi-line detector unit, suitable selection of the rotational speed of the carrier of the computed tomography apparatus and employment of a three-dimensional back-projection algorithm, allow qualitatively high-great images of the object to be produced in every motion phase.
SUMMARY OF THE INVENTION An object of the present invention is to provide an image reconstruction method with which qualitatively high-grade images of periodically moving objects can be registered and reconstructed with high time resolution, even with a conventional computed tomography apparatus.
DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a computed tomography apparatus for implementing the inventive method.
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 schematically show a computer tomograph for implementation of the inventive method.
In order to be able to reconstruct meaningful images of the examined object, measured datasets for successive rotational angles α are required, these extending over a reconstruction angular range β. The reconstruction angular range β lies on the order of magnitude of at least 180�.
The rotational speed n of the carrier 7 usually lies at 45 through 120 revolutions per minute. By comparing the rotational speed n to the duration of the relaxation phase of the heart 9, one can easily determine that the carrier 7 rotates through a rotational angle γ in the relaxation phase of the heart 9 that lies between 135� (500 ms given 45 revolutions per minute) and 576� (800 ms given 120 revolutions per minute).
The above-described method embodiment cannot be employed when the human heart 9 is to be registered during a phase range 16 that lies in the beating phase 12, since the phase range 16 has a time duration that is substantially shorter then the reconstruction time T. The phase range 16 can, for example, have a duration of 50 ms. During this time, the carrier 7 only rotates by 36� given a rotational speed n of 120 revolutions per minute, one-fifth of the minimum reconstruction angular range β. Nonetheless, the heart 9 also can be imaged in this phase range 19 with the same computed tomography apparatus. This occurs as follows.
As previously, measured datasets allocated to the respective rotational angle α are simultaneously registered by the detector lines 3 through 5 at a number of rotational angles α. The measured datasets are registered at least during the phase range 16 of the periodic motion of the heart 9. The heart 9 experiences a number of periods. The number of periods is derived from the condition that the product of the number of periods and a phase angle range δ must at least correspond to the reconstruction angle range β. The phase angle range δ is thereby the angle swept by the carrier 7 during the duration of the phase range 16. As a safety margin, the number of periods should be 1� through 2 times as large as the minimum plurality of periods. The carrier 7, for example, executes a number of rotations that typically lies between 10 and 20. During these rotations, the human heart 9 beats approximately 5 through 20 times. It thus experiences 5 through 20 periods.
It is assumed as an example in FIG. 4 that the phase range 16 has a duration of 50 ms and that the carrier 7 rotates with a rotational speed n of 120 revolutions per minute. Given these assumptions, the carrier 7 sweeps a phase angle range δ=36� during a phase range 16. Given the further assumption that the reconstruction angle range β amounts to 180�, at least 5 and preferably through 10 beating phases 12 of the heart 9 must occur. Given the assumption that the human heart 9 beats with a pulse of 80 beats per minute, the carrier 7 thus must execute a complete revolution at least 7� times, preferably 12 through 15 times.
It is thus possible to find a value�for example, by linear interpolation�for arbitrary slice or displaced positions z from the measured data registered by neighboring detector line 3 through 5 that corresponds very well to the values that would have been registered with what is referred to as an axial scan at this displaced position z. An image of the object 9 then can be reconstructed with the totality of measured data required for the imaging using back-projection algorithms (for example, a convolution back-projection algorithm) that are well-known and employed in computed tomography.
The above-described method cannot be applied when the human heart 9 is to be registered during a phase range 16 that lies in the beating phase 12. The phase range 16 has a time duration that is substantially shorter then the reconstruction time T. The phase range 16 can, for example, have a duration of 50 ms. During this time, the carrier 7 rotates only by 36�, even given a rotational speed n of 120 revolutions per minute, i.e. one-fifth of the minimum reconstruction angle range β. Nonetheless, the heart 9 also can be imaged in this phase range with the same computer tomograph. This occurs as follows.
As before, measured datasets allocated to each rotational angle α are respectively simultaneously registered by the detector lines 3 through 5 at a number of rotational angles α. The measured datasets are thereby registered at least during the phase range 16 of the periodic motion of the heart 9. The feed rate v, however, is now selected such that the object 9 experiences a number of periods during the feed by the detector width D. The number of periods is derived from the condition that the product of the number of periods and a phase angle range δ must at least correspond to the reconstruction angle range β. The phase angle range δ is thereby the angle swept by the carrier 7 during the duration of the phase range 16. As a safety margin, the plurality of periods should be 1� through 2 times as great as the minimum number of periods.
Let is be assumed as an example that the phase range 16 has a duration of 50 ms and that the carrier 7 rotates with a rotational speed n of 120 revolutions per minute. Given these assumptions, the carrier 7 sweeps a phase angle range δ=36� during a phase range 16. Given the further assumption that the reconstruction angle range β amounts to 180�, at least 5, preferably 8 through 10, beating phases 12 of the heart 9 would have to be covered. Given the assumption that the human heart 9 beats with a pulse of 80 beats per minute, the carrier 7 must thus implement a complete revolution at least 7� times, preferably 12 through 15 times. During this number of revolutions, the patient 8 can be displaced no more than the detector width D.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4149079 *Jul 14, 1976Apr 10, 1979Elscint, Ltd.Method of and means for scanning a body to enable a cross-section thereof to be reconstructedUS4868747 *Aug 12, 1987Sep 19, 1989Kabushiki Kaisha ToshibaMethod and system for dynamic computed tomography scanning at cyclic displacement pointsUS5170439 *Jun 11, 1991Dec 8, 1992Picker International, Inc.Cone beam reconstruction using combined circle and line orbitsUS5265013 *Nov 19, 1990Nov 23, 1993General Electric CompanyCompensation of computed tomography data for X-ray detector afterglow artifactsUS5751782 *Apr 22, 1996May 12, 1998Ge Yokogawa Medical Systems, LimitedX-ray computerized tomography apparatus and method for controlling the sameUS5832051 *May 1, 1997Nov 3, 1998Siemens AktiengesellschaftMethod and apparatus for radiological examination of cardiac phases of a patientUS5848114 *Mar 21, 1997Dec 8, 1998Hitachi Medical CorporationComputerized tomography systemUS5889525 *Jun 24, 1996Mar 30, 1999Commissariat A L'energie AtomiqueProcess for the reconstruction of three-dimensional images on a mobile or deformable objectUS6002738 *Jul 7, 1995Dec 14, 1999Silicon Graphics, Inc.System and method of performing tomographic reconstruction and volume rendering using texture mappingUS6047080 *Jun 19, 1996Apr 4, 2000Arch Development CorporationMethod and apparatus for three-dimensional reconstruction of coronary vessels from angiographic imagesUS6149592 *Nov 26, 1997Nov 21, 2000Picker International, Inc.Integrated fluoroscopic projection image data, volumetric image data, and surgical device position dataUS6154516 *Sep 18, 1998Nov 28, 2000Picker International, Inc.Cardiac CT systemUS6236705 *Jun 17, 1999May 22, 2001Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National DefenceMethod for tracing organ motion and removing artifacts for computed tomography imaging systemsEP0370341A2Nov 11, 1989May 30, 1990General Electric CompanyMethod for reducing motion induced image artifacts in projection imagingWO1999007283A1Jun 23, 1998Feb 18, 1999Elscint LtdCardiac imaging* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6925141Sep 23, 2003Aug 2, 2005Siemens AktiengesellschaftMethod for imaging in the computer tomography of a periodically moved object to be examined and CT device for carrying out the methodUS6937690Nov 5, 2003Aug 30, 2005Siemens AktiengesellschaftMethod for computed tomography of a periodically moving object to be examined, and a CT unit for carrying out this methodUS7127025Nov 24, 2004Oct 24, 2006Siemens AktiengesellschaftMethod for production of tomographic section images of a periodically moving object with a number of focus detector combinationsUS7486762Apr 23, 2004Feb 3, 2009Siemens AktiengesellschaftProduction of CT images by spiral reconstruction of an object for examination moving in a partially cyclical mannerUS7599466 *Apr 7, 2006Oct 6, 2009Siemens AktiengesellschaftOperating method for X-ray equipmentUS7653231 *May 2, 2006Jan 26, 2010Ziosoft, Inc.Image processing method and computer readable mediumUS7715603Jan 30, 2004May 11, 2010Siemens AktiengesellschaftMethod for processing available time/phase-dependent primary data sets of a computer tomograph of a displaced object to form a three-dimensional image sequenceUS7822467Nov 10, 2004Oct 26, 2010Siemens AktiengesellschaftMethod for producing CT images of a cyclically moving object to be examinedUS7953267 *Jul 26, 2007May 31, 2011Siemens AktiengesellschaftMethod for the three-dimensional representation of a structure influenced by a periodic process, and medical imaging systemUS8055045 *Mar 11, 2005Nov 8, 2011Hitachi Medical CorporationMethod and system for collecting image data from image data collection range including periodically moving partUS8279997 *May 9, 2007Oct 2, 2012Koninklijke Philips Electronics N.V.Dynamic computed tomography imagingUS20140016847 *Jul 13, 2012Jan 16, 2014General Electric CompanyMulti-phase computed tomography image reconstructionCN101138504BSep 7, 2007Jan 11, 2012东芝医疗系统株式会社X-ray image diagnosis apparatus and a method for generating image dataCN101454804BMay 9, 2007May 1, 2013皇家飞利浦电子股份有限公司Dynamic computed tomography imagingEP1769743A1 *Jun 15, 2005Apr 4, 2007Hitachi Medical CorporationRadiotomograph* Cited by examinerClassifications U.S. Classification382/131, 382/132, 378/8, 378/95International ClassificationA61B5/0402, A61B6/03, A61B6/00, A61B5/0456Cooperative ClassificationA61B6/541, A61B6/027, A61B6/032, A61B6/4085, A61B5/0456European ClassificationA61B6/54B, A61B6/03B, A61B6/40L6Legal EventsDateCodeEventDescriptionSep 16, 2010FPAY Year of fee payment: 8Sep 11, 2006FPAY Year of fee payment: 4Jan 30, 2003ASAssignmentOwner name: SIEMENS AKTIENGESELLSCHAFT, GERMANYFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BRUDER, HERBERT;FLOHR, THOMAS;OHNESORGE, BERND;AND OTHERS;REEL/FRAME:013704/0057;SIGNING DATES FROM 20000405 TO 20000501Owner name: SIEMENS AKTIENGESELLSCHAFT WITTELSBACHERPLATZ 2MUNRotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google