Sep 13, 2012
Innovation: patent applications review
A round-up of the latest international patent applications in medical imaging.
Photoacoustic system detects deep vein thrombosis
InCube Labs (San Jose, CA) has developed an apparatus for detecting deep vein thrombosis via photoacoustic measurement of haemoglobin in different oxygenation states within tissue (WO/2012/109394). The detection system includes at least two sources that emit light at different wavelengths, as well as an acoustic transducer, a data converter and a processor. The light sources are directed onto the patient's skin, producing a photoacoustic signal that's correlated with the absorbance of the two wavelengths by a target tissue region beneath the skin. The transducer detects the photoacoustic signal and transduces it into a correlated electrical signal. The data converter then converts this into a digital signal, which is analysed by the processor to detect the presence of deep vein thrombosis within the target region.
Retrospective method eases MRI distortion correction
Brainlab of Germany has published details of a method for correcting MR image distortion, in which the correction procedure is carried out retrospectively using graphical data processing (WO/2012/103949). After acquisition of the MR image data set, its distortion is determined by registering the acquired data set to a previously available, less distorted or undistorted image data set of roughly the same body region. A transformation is determined from this image registration process and applied to the MR image data set to correct its distortion.
Fluorescence offers intraoperative cancer delineation
Most cancers are currently excised without any intraoperative margin control, and post-operative methods that inspect 1–2% of the surgical margin are prone to sampling errors. To address this shortfall, a team at the University of Massachusetts Lowell has invented an optical imaging system that enables evaluation of the surgical margin in vivo and in real-time (WO/2012/112911). The system enables simultaneous fluorescence and fluorescence polarization imaging, with the image contrast enhanced using fluorescent agents that are already approved for diagnostic use in patients.
PET data resolve ambiguity in MR attenuation map
Philips Electronics of the Netherlands has described a means to resolve ambiguity in an MR attenuation map used in a PET/MR system (WO/2012/120422). When generating a MR attenuation map, an MR image is segmented to identify the patient's body outline, soft tissue structures, and ambiguous structures comprising bone and/or air. To distinguish between bone and air, a nuclear emission image (for example, PET) of the same patient or region-of-interest is segmented. The segmented functional image data are then correlated to the segmented MR image data to distinguish bone and air. Appropriate radiation attenuation values are assigned to identify air and bone voxels in the segmented MR image, and the MR attenuation map is generated from the enhanced segmented MR image (in which ambiguity has been resolved). The attenuation map is used to generate an attenuation-corrected nuclear image, which is displayed to the user.
Digital mammography can deliver high dynamic range
UK-based X-ray imaging specialist Dexela has developed a breast imaging method that can create a high dynamic range mammography image using a restricted dynamic range full-field digital mammogram (WO/2012/104336). The method involves acquiring a sequence of breast images with different exposure parameters, using a digital flat-panel X-ray detector. These image data sets are then combined to create a single full-field digital mammogram with a greater dynamic range than that of any single component image. The filing also discloses mammography apparatus and systems required to obtain images according to the described method.
High accuracy measurements of elastic modulus
Hitachi Medical Corporation of Japan has created a diagnostic ultrasound apparatus that measures elastic modulus with high accuracy over a wide area using shear wave generation (WO/2012/105152). The system includes an ultrasound probe that sends and receives echo signals from inside a living body, and a strain-computing unit that receives the echo signal by radiating a displacement-detecting beam, and computes the strain information in a specified region. Using this strain information, a second region contained within the first is selected as the elastic modulus-measurement position. A focused beam is radiated into the body to displace the tissue, and an elastic modulus-computing unit receives an echo signal from the body by radiating a second displacement-detecting beam. This unit detects the shear wave displacement due to the focused beam and computes the elastic modulus in the second region. A strain image is displayed based on strain information in the first region and the elastic modulus.
About the author
Tami Freeman is editor of medicalphysicsweb.