System and method of image reconstruction using a temporal subset of sparsified image data

Abstract

A tomographic system includes a gantry having an opening for receiving an object to be scanned, a radiation source, a detector positioned to receive radiation from the source that passes through the object, and a computer. The computer is programmed to acquire a scan dataset of the object, define a temporal subset of the acquired scan dataset for image reconstruction, reconstruct a prior image using the acquired scan imaging dataset, and reconstruct a refined image using the defined subset of scan data and the prior image.

1 . A tomographic system comprising:
 a gantry having an opening for receiving an object to be scanned;   a radiation source;   a detector positioned to receive radiation from the source that passes through the object; and   a computer programmed to:
 acquire a short scan dataset of the object; 
 define a temporal subset of the acquired short scan dataset for image reconstruction; 
 reconstruct a short scan image using the acquired short scan dataset; and 
 iteratively reconstruct a refined image using a sparsified set of data that is based on at least the defined temporal subset of the short scan dataset. 
   
     
     
         2 . The tomographic system of  claim 1  wherein the defined temporal subset of the acquired short scan dataset comprises approximately half of an angular range of the short scan dataset. 
     
     
         3 . The tomographic system of  claim 1  comprising a motion monitor configured to monitor motion of the object, wherein the computer is programmed to define the temporal subset of the acquired scan dataset based on data obtained from the motion monitor. 
     
     
         4 . The tomographic system of  claim 1  wherein the computer is programmed to acquire the short scan dataset during a single cardiac cycle. 
     
     
         5 . The tomographic system of  claim 1  wherein the tomographic system comprises more than one radiation source. 
     
     
         6 . The tomographic system of  claim 1  wherein the tomographic system is a computed tomography (CT) system. 
     
     
         7 . The tomographic system of  claim 1  wherein the object is a heart of a patient. 
     
     
         8 . The tomographic system of  claim 1  wherein the computer is programmed to acquire the short scan dataset over 180° of a CT gantry rotation plus a fan angle of the detector. 
     
     
         9 . The tomographic system of  claim 8  wherein the fan angle of the detector is approximately 60°. 
     
     
         10 . The tomographic system of  claim 1  wherein the defined temporal subset of the acquired short scan dataset is a subset of the short scan dataset that is obtained over a CT gantry circumferential range between 90° and 130°. 
     
     
         11 . A method of tomographic imaging comprising:
 positioning a detector to receive radiation passing through a heart of a patient;   acquiring projection datasets of the heart using the detector;   reconstructing a first image of the heart using the acquired projection datasets;   defining a temporally reduced number of projection datasets from the acquired projection datasets; and   iteratively reconstructing a final image of the heart using a sparsified set of data that is based on at least the temporally reduced number of projection datasets.   
     
     
         12 . The method of  claim 11  wherein the step of iteratively reconstructing the final image of the heart comprises using the sparsified set of data that is based on the first image. 
     
     
         13 . The method of  claim 11  wherein defining the temporally reduced number of projection datasets comprises defining a reduced number of sequentially acquired projection datasets of the heart. 
     
     
         14 . The method of  claim 11  wherein acquiring projection datasets of the heart comprises acquiring the projection datasets during a single cardiac cycle. 
     
     
         15 . The method of  claim 11  wherein acquiring the projection datasets comprises acquiring the projection datasets over a CT gantry angular range of approximately 180° plus a fan angle of the detector. 
     
     
         16 . The method of  claim 15  wherein the fan angle is approximately 60°. 
     
     
         17 . The method of  claim 11  wherein defining the temporally reduced number of projection datasets comprises temporally defining datasets acquired over a CT gantry angular range between 90° and 130°. 
     
     
         18 . The method of  claim 11  wherein reconstructing the prior image of the heart comprises reconstructing the prior image using a filtered backprojection algorithm. 
     
     
         19 . A non-transitory computer readable storage medium having stored thereon a computer program comprising instructions which when executed by a computer cause the computer to:
 acquire a set of projections from a cardiac region of a patient;   reconstruct a prior image of the cardiac region using the acquired set of projections; and   iteratively reconstruct a refined image of the cardiac region using a temporally defined and sparsified subset of the acquired set of projections.   
     
     
         20 . The computer readable storage medium of  claim 19  wherein the computer is programmed to iteratively reconstruct the refined image of the cardiac region using the prior image. 
     
     
         21 . The computer readable storage medium of  claim 19  wherein the computer is caused to iteratively reconstruct the refined image of the cardiac region using sequentially obtained projections. 
     
     
         22 . The computer readable storage medium of  claim 19  wherein the acquired set of projections is obtained of the cardiac region during a single cardiac cycle. 
     
     
         23 . The computer readable storage medium of  claim 19  wherein the computer is caused to:
 acquire the set of projections over an angular range spanning approximately 180° of circumferential coverage plus a fan angle of a CT detector used to acquire the set of half-scan projections. 
 
     
     
         24 . The computer readable storage medium of  claim 23  wherein the fan angle is approximately 60°. 
     
     
         25 . The computer readable storage medium of  claim 19  wherein the computer is caused to reconstruct the prior image using a filtered backprojection algorithm. 
     
     
         26 . The computer readable storage medium of  claim 19  wherein the subset of the set of projections comprises half-scan projections obtained over a circumferential range of a CT detector spanning between 90° and 130.