Neural networks shed light on MR contrast
Contrast agents are employed within MRI to estimate vascular properties such as blood flow, blood volume and transfer constant of tissue microvessels. However, the relationship between contrast in the MR image and contrast-agent concentration is not linear. Instead, it is dependent upon factors such as the nature of the sequence, the nature of the tissue and the tissue concentration of contrast agent - thus limiting the reliability of estimating vascular properties using MRI. To address this issue, researchers from the Henry Ford Health System (Detroit, MI) have developed systems, methods and apparatus to correlate changes in MRI data with contrast agent concentration, using an adaptive neural network (WO/2009/020687).
PET and MR imaging come together
Philips Electronics of the Netherlands has published details of a hybrid MR/PET imaging system (WO/2009/013650). The system includes: PET detectors encircling an examination region and surrounded by galvanic isolation and coincidence detection electronics; an MR scanner, comprising a main magnet and a magnetic field gradient assembly, that acquires data from an area overlapping the region enclosed by the PET detectors; and a radiofrequency coil with a series of conductors surrounded by a radiofrequency screen. The PET detectors are sited outside of the screen and thus shielded at the MR frequency. According to Philips, the system's key benefits include: MR-compatible shielding (using a non-conductive, non-ferromagnetic heavy-atom oxide material) for the PET detectors; PET detectors that are suitably shaped for the restricted space in a typical MR scanner bore; and well-defined regions in the scanner from which the radiofrequency signals are excluded, and in which the PET detectors can be situated.
Multimodal nanoparticles target non-invasive bioimaging
Scientists at the University of Florida Research Foundation (Gainesville, FL) have developed multimodal nanoparticles for use in non-invasive bioimaging (WO/2009/032752). The nanoparticles contain contrast agents for photoacoustic tomography, as well as one or more other imaging modality, such as luminescence, X-ray and MR imaging. The nanoparticles can have a dielectric core comprising at least one oxide (for example, silicon dioxide) and coated with a metal (for example, gold). The particles can also be metal speckled. In addition to use as contrast agents, the nanoparticles can be employed for therapeutic purposes, such as thermal ablation of tumours or cell destruction via neutron capture methods.
Dual-modality sensor reveals internal injuries
Spectral Energetics of Beavercreek, OH, has unveiled a device that can non-invasively detect internal pathologic injury resulting from conditions including pneumothorax, haemothorax, compartment syndrome, epidural haematoma and subdural haematomas (WO/2009/025766). The sensor system is based around a dual-modality wand-detector that integrates an electromagnetic transceiver and an ultrasound transducer to simultaneously obtain interrogation signatures from the tissue. The system is capable of impedance matching to minimize reflected signals and provide improved images of the trauma site. The interrogation signals are processed by a signal-processing system that utilizes dual-modality and impedance software to obtain trauma condition data.
Breast CT system offers high-resolution imaging
A prone breast X-ray imaging system that can create high-resolution (25 µm or better) images of a whole breast is the subject of international patent application WO/2009/026587. According to Fischer Medical Technologies (Broomfield, CO), the system can image the entire breast in three dimensions, based on multiple projection views from a 1D or 2D detector. Data can be acquired and reconstructed with a limited number of views from limited angles, or with conventional cone-beam CT algorithms. The resulting 3D image reveals fine micro-calcifications and small masses throughout the breast, improving the diagnosis of malignancy compared with 2D digital mammography. Injecting intravenous contrast can provide morphologic information on the existing tumour burden in the breast, a capability that may remove the need for an independent contrast MRI exam of the breast. An integrated biopsy capability permits convenient and rapid biopsy of any area suspect for malignancy.
Demagnetization enables MRI despite magnetic implants
Implantable medical devices that contain magnets - such as cochlear implants, for example - can preclude patients from undergoing MRI examinations. In international patent application WO/2009/012130, Med-El Elektromedizinische Geraete of Austria details a means of demagnetizing and remagnetizing magnetic elements in such a device to enable MR imaging. The method comprises: demagnetizing the magnetic element in an implanted device by exposing it to an external demagnetizing magnetic field; performing the MR exam on the patient; and then remagnetizing the element (without removing it from the implanted device) by exposing it to an external remagnetizing magnetic field.
CT scheme enhances quality of fluoroscopic imaging
Israeli medical device company superDimension has published details of a CT-enhanced fluoroscopy technique for guiding instruments inside the body during medical procedures (WO/2009/024852). The method involves performing a pre-operative CT scan, the data from which are transformed into a 3D CT volume for use in treatment planning. Suspicious lesions are identified and the recommended path of the instrument (such as a bronchoscope) to the target area is determined. The bronchoscope (or catheter, guidewire, needle, etc) is made from a traceable material or includes radio-opaque markers that can be viewed on a fluoroscope. This enables tracking of its path inside the body via fluoroscopic images, which can be registered to and fused with the initial CT images. As the fluoroscopic imaging occurs in real-time, a tracing element - such as temporary or permanently implanted markers around the target - can be utilized to track the movement of the internal soft tissue near the area of interest as the patient breathes.