Method and System for Detection of Contrast Injection Fluoroscopic Image Sequences

Abstract

A method and system for detecting a spatial and temporal location of a contrast injection in a fluoroscopic image sequence is disclosed. Training volumes generated by stacking a sequence of 2D fluoroscopic images in time order are annotated with ground truth contrast injection points. A heart rate is globally estimated for each training volume, and local frequency and phase is estimated in a neighborhood of the ground truth contrast injection point for each training volume. Frequency and phase invariant features are extracted from each training volume based on the heart rate, local frequency and phase, and a detector is trained based on the training volumes and the features extracted for each training volume. The detector can be used to detect the spatial and temporal location of a contrast injection in a fluoroscopic image sequence.

1 . A method for detecting a spatial and temporal location of a contrast injection in a fluoroscopic image sequence, comprising:
 receiving a fluoroscopic image sequence;   generating a 3D volume by stacking the fluoroscopic image sequence; and   detecting a spatial and temporal location of the contrast injection in the fluoroscopic image sequence by processing the 3D volume using a trained contrast injection detector.   
     
     
         2 . The method of  claim 1 , wherein said step of generating a 3D volume comprises:
 stacking a plurality of 2D fluoroscopic images in the fluoroscopic image sequence in time order; and   interpolating the stacked 2D fluoroscopic images to generate a continuous 3D volume having two spatial dimensions and one time dimension.   
     
     
         3 . The method of  claim 1 , wherein the trained contrast injection detector is trained using a probabilistic boosting tree (PBT) based on training examples and frequency and phase invariant features extracted from the training examples. 
     
     
         4 . The method of  claim 1 , wherein the 3D volume has two spatial dimensions and one temporal dimension and said step of detecting a spatial and temporal location of the contrast injection in the fluoroscopic image sequence comprises:
 detecting a contrast injection point in the 3D volume using the contrast injection detector, wherein coordinates of the detected contrast injection point give the spatial and temporal location of the contrast injection.   
     
     
         5 . An apparatus for detecting a spatial and temporal location of a contrast injection in a fluoroscopic image sequence, comprising:
 means for receiving a fluoroscopic image sequence;   means for generating a 3D volume by stacking the fluoroscopic image sequence; and   means for detecting a spatial and temporal location of the contrast injection in the fluoroscopic image sequence by processing the 3D volume using a trained contrast injection detector.   
     
     
         6 . The apparatus of  claim 5 , wherein said means for generating a 3D volume comprises:
 means for stacking a plurality of 2D fluoroscopic images in the fluoroscopic image sequence in time order; and   means for interpolating the stacked 2D fluoroscopic images to generate a continuous 3D volume having two spatial dimensions and one time dimension.   
     
     
         7 . The apparatus of  claim 5 , wherein the trained contrast injection detector is trained using a probabilistic boosting tree (PBT) based on training examples and frequency and phase invariant features extracted from the training examples. 
     
     
         8 . A computer readable medium encoded with computer executable instructions for detecting a spatial and temporal location of a contrast injection in a fluoroscopic image sequence, the computer executable instructions defining steps comprising:
 receiving a fluoroscopic image sequence;   generating a 3D volume by stacking the fluoroscopic image sequence; and   detecting a spatial and temporal location of the contrast injection in the fluoroscopic image sequence by processing the 3D volume using a trained contrast injection detector.   
     
     
         9 . The computer readable medium of  claim 8 , wherein the computer executable instructions defining the step of generating a 3D volume comprise computer executable instructions defining the steps of:
 stacking a plurality of 2D fluoroscopic images in the fluoroscopic image sequence in time order; and   interpolating the stacked 2D fluoroscopic images to generate a continuous 3D volume having two spatial dimensions and one time dimension.   
     
     
         10 . The computer readable medium of  claim 8 , wherein the trained contrast injection detector is trained using a probabilistic boosting tree (PBT) based on training examples and frequency and phase invariant features extracted from the training examples. 
     
     
         11 . The computer readable medium of  claim 8 , wherein the 3D volume has two spatial dimensions and one temporal dimension and the computer executable instructions defining the step of detecting a spatial and temporal location of the contrast injection in the fluoroscopic image sequence comprise computer executable instructions defining the step of:
 detecting a contrast injection point in the 3D volume using the contrast injection detector, wherein coordinates of the detected contrast injection point give the spatial and temporal location of the contrast injection.