Medical Imaging

Most Recent Inventions

Monomeric Fluorescent Protein-Ligand Complexes with Strong Fluorescence in the Far-Red Region

Research from the University of Wisconsin-Washington County in collaboration with the Institute for Stem Cell Biology and Regenerative Medicine in India, has resulted in the development of monomeric variants of the naturally occurring Sandercyanin Fluorescent Protein (SFP) using site-directed mutagenesis. This work has stemmed from earlier research focused on development of the tetrameric form of SFP, a biliverdin-binding lipocalin protein originally isolated from the mucus of the blue walleye fish, Sander vitreus. Monomeric variants of SFP (mSFPs) have been found to possess the same non-covalent, bili-binding characteristics of the tetramer but are one-quarter the size (~18.6kDa) and do not oligomerize. They are therefore anticipated to be more useful in a host of biotechnology applications. Like the tetrameric form, the mSFPs have a large stokes shift (375nm/675nm) and fluoresce in the far-red or near infrared region, which is advantageous for a wide range of applications including investigation of protein-protein interactions, spatial and temporal gene expression, assessing cell biology distribution and mobility, studying protein activity and protein interactions in vivo, as well as cancer research, immunology, and stem cell research and sub-cellular localization. In addition, the newly developed mSFP’s far-red fluorescence is particularly advantageous for in vivo, deep-tissue imaging.

Long-Lived Gadolinium-Based Agents for Tumor Imaging and Therapy

UW–Madison researchers have synthesized the first long-lived tumor-specific contrast agents for general broad spectrum tumor imaging and characterization. The new, gadolinium (Gd)-labeled analogs utilize an alkylphosphocholine carrier backbone. Their formulation properties render them suitable for injection while retaining tumor selectivity.

High Accuracy Angle Measuring Device for Industrial, Medical, Scientific or Recreational Use

A UW-Stout researcher has developed a high-accuracy angle measurement system that addresses the problems inherent to commercially available systems. In this novel device, a high accuracy rotary optical encoder is controlled by a microprocessor. The encoder consists of rotating optical disks and sensors that are precisely formed and placed to read angles with 0.001 arc second sensitivity (average) and better than ±0.1 arc second accuracy (single readings), which is comparable to the accuracy of the high-end commercial encoders currently on the market. This accuracy is maintained with strategies that combat the mechanical sources of error that are known disadvantages of other devices. The system can also be adjusted to compensate for any asymmetrical shifts that may occur. Mechanical sources of error and noise are further minimized by precision placement of disks and sensors, as well as low-friction reference points that keep components centered and level during rotation. In addition, multiple sensor heads eliminate major readout errors and remove the need for recalibration. All of these features and benefits are contained within a design that is both compact and portable. Beyond high accuracy and portability, the cost of this new angle measurement system is substantially lower than a high-end commercial system because it is easily constructed from readily available industrial grade components, bringing the production cost to roughly $2,000. Strikingly, this cost is comparable to the advertised price of other rotary position encoders that are less than one tenth as accurate. Its high accuracy, low cost, and portability make this new angle measurement system a strong option for use in virtually any of the current applications for absolute rotary encoders.

New Technology for Measuring Stress in Tendons, Ligaments and Muscles

UW–Madison researchers have developed a new device and technique for dynamically, noninvasively and accurately measuring longitudinal stress in tendons, muscles and ligaments in vivo.

The inventors use skin-mounted accelerometers to measure transverse wave speeds in superficial tissues under time-varying loading scenarios. Such wave speed propagation metrics are then used to determine tissue stress based on a wave propagation model.

Digital Otoscope for Optimal Access, Visualization

UW–Madison researchers have designed an otoscope featuring a small camera that is mounted on a narrow tip and able to ‘look around’ obstructions such as earwax. The narrow tip also permits other medical instruments to be inserted into the ear while the otoscope is being used (e.g., a curette for removing earwax or foreign objects). A remarkable view of the tympanic membrane is achieved, facilitating proper diagnosis.

Notable features include a disposable, light-conducting speculum sleeve with distal tip smaller than 2 mm. In addition, images may be captured directly from the device and stored in the patient record in compliance with Federal law.

Most Recent Patents

Faster, Higher Quality Medical Imaging

UW–Madison researchers have developed a reconstruction technique that uses a non-patient-specific signal model (e.g., a physical or physiological model) to improve image quality without compromising accuracy.

While other methods make use of such analytical models in the post-processing stage, the new technique utilizes the model earlier in the process, yielding clinically useful images from highly undersampled data. The reconstruction process is designed to accommodate deviations from the model when appropriate.

Method for Error-Compensated Chemical Species Signal Separation with Magnetic Resonance Imaging

A UW–Madison researcher has developed a method for separating the relative signal contributions of multiple chemical species in which echo signal information containing errors is discarded during signal separation. The method enables production of an image with an MRI system in which relative signal contributions from the chemical species are separated while accounting for errors. It requires using multiple echo signals acquired at different times to form signal models that account for relative signal components for each chemical species. Then, each echo signal that contains errors is identified and discarded from the relative signal components for each chemical species. Finally, an image is produced using the reliable data from the relative signal components of the chemical species.

Robust Magnetic Field Map Estimation Improves MRI Fat-Water Separation

UW–Madison researchers have developed a method to improve the robustness of chemical species separation in MRI. Their approach uses an object-based initial estimate of the B0 field map.

More specifically, an MRI system scans a subject to acquire k-space data at different echo times and subsequently reconstructs images. The pixel values of these images are used to estimate a distribution of magnetic susceptibility values found in the subject. A magnetic field inhomogeneity map is estimated from the magnetic susceptibility distribution, and chemical species separation (e.g., fat-water separation) then can be performed.

The new approach is intended to improve the robustness of existing techniques for chemical shift encoded chemical species separations.