Abstract: A method is disclosed for generating a time resolved series of time and energy subtracted 3D volume reconstructions, e.g., using a switched dual energy C-Arm type X-ray imaging system or a bi-plane type X-ray imaging system.

Abstract: A system and method for generating time-resolved 3D medical images of a subject includes acquiring a time series of two-dimensional (2D) data sets from a portion of the subject using a magnetic resonance imaging (MRI) system and reconstructing the time series of 2D data sets into a 2D time series of images of the subject having a given frame rate. The process also includes acquiring a time-independent, 3D volume of the portion of the subject and combining the 2D time series of images of the subject with the time-independent 3D volume of the subject to generate a set of time-dependent 3D volume images of the portion of the subject at the given frame rate.

Abstract: A method is disclosed of providing time dependent three dimensional imaging of a region of a patient comprising blood vessels in a perfusion bed.

Abstract: An image reconstruction method includes reconstructing a composite image of a subject using a conventional reconstruction method. The composite image employs the best information available regarding the subject of the scan and this information is used to constrain the reconstruction of a highly undersampled image frames or improve the SNR of image frames. A blurred and normalized weighting image is produced from image frame data, and this normalized weighting image is multiplied by the composite image.

Abstract: A highly constrained image processing method is used to improve the quality, including spatial resolution and signal-to-noise ratio (SNR), of ultrasound image frames. Ultrasound image frames are accumulated to form a composite image that contains a priori information about the subject being imaged. This composite image is used in a HYPR processing method to improve the quality of the ultrasound image frame. For example, the SNR of the composite image is increased as a function of the number of ultrasound image frames used to produce it, and this increased SNR is passed on to each highly constrained image frame. Additionally, high spatial resolution ultrasound images are produced using an undersampled sampling density, and the quality of these images is restored to substantially the same level as a fully sampled image.

Abstract: A method is disclosed for producing a computed tomographic image of a subject, the method including: using a radiation source and detector, obtaining radiation transmission information relating to a region of interest in the subject; using the source and detector; obtaining a series of projection images of the region of interest. Each projection image is obtained by: directing an imaging beam of radiation from the source through the region of interest onto the detector along a respective direction; the detector having a detection area.

Abstract: Mask projection views are obtained prior to the arrival of a contrast agent during a dynamic contrast enhanced MRA study. After the arrival of the contrast agent, a set of undersampled contrast enhanced projection views are obtained for each of a plurality of time frames. Corresponding mask projection views are subtracted from the contrast enhanced projection views to provide sparse contrast enhanced projection view sets. A phase contrast scan of a region of interest is performed prior to or after the arrival of the contrast agent. The phase contrast image is used as a composite image in a HYPR reconstruction of the sparse projection view sets to produce first pass contrast enhanced images. Iterative HYPR reconstructions can also be performed to remove venous information from the reconstructed images.

Abstract: Two-dimensional or three-dimensional, time-resolved MR frame images are acquired during a dynamic study of a subject. A composite MR image is produced and this is used to reconstruct each image frame by weighting the backprojection of each projection view acquired for that image frame. The composite image may be reconstructed from views acquired separately, or it may be produced by combining views acquired during the course of the dynamic study. A number of different clinical applications of the method are described.

Abstract: Acquisition of MR data during a fMRI study employs a hybrid PR pulse sequence to acquire projection views from which multi-slice image frames may be reconstructed that depict the BOLD response to an applied stimulus or performed task. Composite images are reconstructed at each slice using the combined interleaved projection views from all the acquired image frames. The composite images are used to reconstruct the highly undersampled image frames.

Abstract: A night vision device and method for filtering a series of image frames that depict a moving subject, which thereby improves the signal-to-noise ratio of each image frame, is provided. A composite image is formed for each image frame by combining pixel values in a current image frame with pixel values in composite images corresponding to image frames acquired before the current image frame. Additionally, pixels values in image frames acquired subsequent to the acquisition of the current image frame are included when forming the composite image. A bi-directional recursive filter is used to weight the contributions from the previous composite images and subsequent image frames with a decay constant. Motion of the imaging system is optionally compensated for by establishing a moving reference frame and shifting the image frames to account for this motion; thus, registering the image frames before filtering the current image frame.

Abstract: A method for generating time-resolved 3D medical images of a subject by imparting temporal information from a time-series of 2D medical images into 3D images of the subject. Generally speaking, this is achieved by acquired image data using a medical imaging system, generating a time-series of 2D images of a ROI from at least a portion of the acquired image data, reconstructing a 3D image substantially without temporal resolution from the acquired image data, and selectively combining the time series of 2D images with the 3D image. Selective combination typically involves registering frames of the time-series of 2D images with the 3D image, projecting pixel values from the 2D image frames “into” the 3D image, and weighting the 3D image with the projected pixel values for each frame of the time-series of 2D images.

Abstract: A method for generating time-resolved 3D medical images of a subject by imparting temporal information from a time-series of 2D medical images into 3D images of the subject. Generally speaking, this is achieved by acquiring image data using a medical imaging system, generating a time-series of 2D images of a ROI from at least a portion of the acquired image data, reconstructing a 3D image substantially without temporal resolution from the acquired image data, and selectively combining the time series of 2D images with the 3D image. Selective combination typically involves registering frames of the time-series of 2D images with the 3D image, projecting pixel values from the 2D image frames “into” the 3D image, and weighting the 3D image with the projected pixel values for each frame of the time-series of 2D images.

Abstract: A cardiac gated acquisition of MR data during a breath-hold employs a hybrid PR pulse sequence to acquire projection views from which image frames may be reconstructed at a plurality of cardiac phases during each heartbeat. Composite images are reconstructed at each cardiac phase using interleaved projection views acquired during all the heartbeats. The composite images are used to reconstruct the highly undersampled image frames at the same cardiac phase using a highly constrained backprojection method.

Abstract: Mask projection views are obtained prior to the arrival of a contrast agent during a dynamic contrast enhanced MRA study. After the arrival of the contrast agent, a set of undersampled contrast enhanced projection views are obtained for each of a plurality of time frames. Corresponding mask projection views are subtracted from the contrast enhanced projection views to provide sparse contrast enhanced projection view sets. A phase contrast scan of a region of interest is performed prior to or after the arrival of the contrast agent. The phase contrast image is used as a composite image in a HYPR reconstruction of the sparse projection view sets to produce first pass contrast enhanced images. Iterative HYPR reconstructions can also be performed to remove venous information from the reconstructed images.

Abstract: A series of velocity encoded MR image frames are acquired. To increase the temporal resolution of the acquired image frames radial projections are acquired and each image frame is highly undersampled. The radial projections for each velocity encoding direction are interleaved throughout the scan and a composite phase image is reconstructed from these and used to reconstruct a velocity image for each image frame in a highly constrained backprojection method.

Abstract: Projection views of the moving heart and stationary background tissues are acquired and processed to provide corresponding moving tissue projection views. An average image is reconstructed in a conventional manner and a moving tissue image is reconstructed using a highly constrained backprojection method and a composite image formed from selected moving tissue projection views. The average image is then combined with the moving tissue image. The method is disclosed in a cardiac gated MRI scan.

Abstract: A magnetic resonance angiogram (MRA) is acquired using a contrast enhancement method in which a series of NMR images are rapidly acquired during a time resolved phase of the examination in which the contrast bolus makes a first pass through the arteries and veins. Arterial and venous voxels are automatically identified in the images using either of two disclosed methods. The signals from identified arterial voxels are used to produce an arterial contrast enhancement reference curve that is used to segment arterial voxels by a correlation process. Venous voxels are segmented in the same manner using a calculated venous contrast enhancement reference curve.

Abstract: Two-dimensional or three-dimensional, time-resolved CT frame images are acquired during a dynamic study of a subject. A composite image is produced and this is used to reconstruct each CT frame image by weighting the backprojection of each projection view acquired for that image frame by the corresponding value in the composite image. This weighted backprojection enables artifact-free image frames to be produced with far fewer projection views of the subject. The composite image may be reconstructed from views acquired separately, or it may be produced by combining views acquired during the course of the dynamic study.

Abstract: A highly constrained image processing method is used to improve the quality, including spatial resolution and signal-to-noise ratio (SNR), of ultrasound image frames. Ultrasound image frames are accumulated to form a composite image that contains a priori information about the subject being imaged. This composite image is used in a HYPR processing method to improve the quality of the ultrasound image frame. For example, the SNR of the composite image is increased as a function of the number of ultrasound image frames used to produce it, and this increased SNR is passed on to each highly constrained image frame. Additionally, high spatial resolution ultrasound images are produced using an undersampled sampling density, and the quality of these images is restored to substantially the same level as a fully sampled image.

Abstract: An image reconstruction method includes reconstructing a composite image of a subject using a conventional reconstruction method. The composite image employs the best information available regarding the subject of the scan and this information is used to constrain the reconstruction of highly undersampled image frames. An image frame is reconstructed using limited acquired data and image quality is improved using a priori information of the subject by weighting pixel values therein by values of corresponding pixels in the composite image.