Browse Prior Art Database

Method and System for Assessment of Motion Differences Between in Combined Images Disclosure Number: IPCOM000169934D
Publication Date: 2008-May-02
Document File: 6 page(s) / 77K

Publishing Venue

The Prior Art Database


A method for assessing motion in images obtained via use of two different imaging modalities is presented. The method for assessing motion differences in images taken by two different imaging modalities allows visualization of the gated PET image data at the highest statistical quality available while still being able to assess the ‘motion content’ that is present between data collected from the two modalities.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 31% of the total text.

Method and System for Assessment of Motion Differences Between in Combined Images


[0001]             The invention relates generally to imaging systems, and more particularly to assessment of motion differences in combined images.   

[0002]             Diagnostic imaging has emerged into an essential aspect of patient care.  Medical images that are obtained during a diagnostic imaging session have evolved as tools that allow a clinician non-invasive means to view anatomical cross-sections of internal organs, tissues, bones and other anatomical regions of a patient.  More particularly, the medical images serve the clinician in diagnosis of disease states, determination of suitable treatment options and/or monitoring the effects of treatment.  As will be appreciated, medical images may be obtained from a broad spectrum of imaging modalities, such as, but not limited to computed tomography (CT) imaging, ultrasound imaging, magnetic resonance (MR) imaging, digital mammography, X-ray imaging, nuclear medicine imaging, or positron emission tomography (PET) imaging. 

[0003]             As will be appreciated, when performing respiratory gating on both CT and PET portions of a combined PET-CT scan, several assumptions are made.  These assumptions generally include assumptions that the respiratory pattern is the same between the two modalities, the motion of the imaged region in both modalities may be modeled from the measured respiratory pattern, and the motion as measured by the CT and determined using a CT-CT registration algorithm may be used to correct the motion in the PET data, to name a few.  The ability to perform motion compensation based on the CT-CT registration relies on these assumptions, and the confidence in the results is increased in as much as one can rule out that the motion compensation algorithm corrected for motion that was actually present in each of the respective scans.   

[0004]             An added complication for PET-CT is the realization that the motion determined within the four-dimensional (4D) CT affects the PET data as part of the attenuation correction.  Image artifacts may occur if the attenuator distribution in the gates of the


does not correspond to the average source and/or attenuator distribution seen during the same 4D PET gates.  An obvious way to quality-check the results is to visualize the non-attenuation-corrected PET gate images along with the CT gate images in a similar animated orthogonal viewing tool.  However, to perform this thoroughly on every whole-body study will significantly impact clinical workflow.  Further, PET NAC images are not always intuitive regarding their interpretation. 

[0005]             It may therefore be desirable to develop a robust technique and system for enabling assessment of motion differences between CT and PET in a combined PET-CT image that advantageously facili...