Encapsulated gas or partial vacuum CT contrast material
Inventors
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-12178626-B2
Publication Date
2024-12-31
Expiration Date
2036-04-20
Abstract
The present invention provides an encapsulated gas or partial vacuum particle contrast media for use in CT imaging. In an exemplary embodiment, the invention provides an enteric contrast medium formulation. An exemplary formulation comprises, (a) an enteric contrast medium comprising a encapsulated gas or partial vacuum particle suspended in water. Exemplary encapsulated gas or partial vacuum particle has a specific gravity between 0.2 and 1.5. In various embodiments, the encapsulated gas or partial vacuum particle is suspended in aqueous media by an agent compatible with enteric administration of the formulation to a subject in need of such administration. In an exemplary embodiment, the contrast material is incorporated into a pharmaceutically acceptable carrier in which the material is suspended homogeneously. In an exemplary embodiment, the encapsulated gas or partial vacuum particle comprises 5% or more of the weight of the contrast material formulation. The invention also provides methods for imaging of the abdomen by dual energy CT or spectral CT contemporaneously with the delivery of the encapsulated gas or partial vacuum particle contrast material into the bowel lumen with or without the deliver of a second complementary contrast material into the blood vessels or other body compartments. The invention also provides methods for the digital separation of CT signal produced by the contrast media of the invention from the CT signal produced by other contrast media or bodily tissues to generate multiple resultant CT images with the contrast medium of the invention subtracted or highlighted.
Core Innovation
The invention provides an encapsulated gas or partial vacuum particle contrast medium formulation for use in CT imaging, particularly enteric CT imaging. The formulation comprises encapsulated gas or partial vacuum particles suspended in an aqueous or oil-based vehicle, typically water, with a suspending agent compatible with enteric administration, such as xanthan gum. The particles have a shell composed primarily of materials like silicon dioxide, silicon-containing rubber, ceramic, or other inert insoluble material and possess specific gravities between approximately 0.2 and 1.5. The formulation can include radiodense materials such as iodine, barium, tungsten, tantalum, bismuth, or ytterbium, either incorporated in the particle shell or in the suspending medium. These agents enable differentiation at CT, dual energy CT (DECT), spectral CT, or photon counting CT from other contrast media or bodily tissues based on distinctive CT numbers and 80:140 kVp CT number ratios.
The invention addresses the problem that current enteric CT contrast materials—positive (iodine or barium-based), neutral, or negative—each have limitations, including inability to differentiate from intravenous contrast agents or natural tissues under CT or even dual energy CT. Positive agents obscure some vital imaging findings in disease states such as trauma, bowel ischemia, and inflammation. Neutral or negative agents lack conspicuity or cause image artifact, and current negative agents are not well tolerated for small bowel use. Dual energy CT technologies currently cannot effectively distinguish iodine and barium-based agents owing to their similar 80:140 kVp CT number ratios. Repeated scans due to diagnostic ambiguities result in additional radiation dose and delays. Furthermore, the available agents cannot simultaneously serve as positive, neutral, and negative contrast material under interpretive control, limiting diagnostic flexibility.
The invention solves these problems by providing encapsulated gas or partial vacuum particles with shell materials that substantially contribute to the CT number of the formulation and modulate the low-to-high voltage CT number ratio. This yields contrast agents exhibiting negative, neutral, or positive CT appearance at conventional CT and allows image post-processing at dual energy or spectral CT to convert the appearance among these contrasts, enhancing material differentiation. These agents improve differentiation from soft tissues and current contrast media, reduce artifacts associated with gas, and enable simultaneous use with other contrast media to generate perfectly co-registered CT images with reduced radiation by obviating the need for multiple scans.
Claims Coverage
The patent contains several inventive features primarily articulated through independent claims concerning methods of CT imaging using the encapsulated gas or partial vacuum particle contrast medium formulation.
Method of CT imaging using specific enteric contrast medium formulation
Oral administration of a diagnostically effective amount of an enteric contrast medium comprising a stable aqueous suspension of 10% to 50% by weight hollow borosilicate microspheres encapsulating gas or partial vacuum suspended in water containing 0.2% to 0.5% xanthan gum as a suspending agent with viscosity 50 to 2400 g/cm-sec, followed by acquiring projection data for CT imaging.
Imaging including multi-material decomposition and reconstruction
Acquiring CT projection data reconstructed into abdominal images where the enteric contrast medium is distinguished from other abdominal materials, enabling 2-, 3-, or multi-material decomposition in image reconstruction.
Simultaneous administration of additional contrast media with distinguishability
Administering a second contrast medium different from the enteric contrast medium by various routes including oral, intrathecal, intravesicular, and others, such that both contrast media are distinguishable in CT images based on X-ray attenuation (CT number) at single energy or dual energy spectra.
Use of contrast media with specific CT number and 80:140 kVp CT ratio properties
The enteric contrast medium has CT numbers less than about −50 HU or greater than about 100 HU, and 80:140 kVp CT number ratios greater than about 2.1 or less than about 0.8 or less than zero, allowing enhanced differentiation in images.
Method for dual energy, spectral, or photon counting CT acquisition of abdomen
Specific use of the above formulation for acquiring contrast enhanced dual energy, spectral, or photon counting CT projection data of the abdomen with the enteric contrast agent distributing in the gastrointestinal tract without decreasing the density of contents, and with small bowel transit time less than 12 hours.
The claims collectively cover methods of CT imaging using orally administered enteric contrast formulations containing encapsulated gas or partial vacuum hollow borosilicate microspheres suspended in water with a suspending agent. They cover image acquisition and processing methods to distinguish these agents from other materials and include simultaneous administration of additional contrast agents distinguishable by CT signal characteristics.
Stated Advantages
Enables differentiation of enteric contrast material from intravenous contrast agents and bodily tissues at single energy and dual energy or spectral CT imaging, reducing diagnostic ambiguity.
Allows digital manipulation of contrast signal to appear as negative, neutral, or positive contrast material under interpreting physician control, providing powerful diagnostic flexibility.
Reduces CT radiation dose by decreasing the need for repeat imaging and enabling lower tube current settings due to adjustable contrast properties.
Provides contrast media that cause less motion and imaging artifact than unencapsulated gas, improving image quality.
Allows simultaneous administration and imaging of multiple contrast agents in different body compartments with near perfect co-registration, enhancing diagnosis of multi-organ injury and complex diseases.
Documented Applications
Use as enteric contrast media for abdominal and pelvic CT imaging to improve visualization of bowel lumen, wall, and pathologies such as bowel ischemia, inflammation, perforation, abscesses, and tumors.
Imaging using dual energy CT, spectral CT, or photon counting CT techniques to differentiate contrast media and bodily tissues based on CT number ratios and X-ray attenuation properties.
Simultaneous administration and imaging of multiple contrast media in different body compartments including oral, intravascular, and surgically created or artificial devices to provide co-registered CT images for diagnosis of trauma, tumors, surgical complications, and inflammatory diseases.
Formulations designed for use in diagnostic CT scans of the abdomen and pelvis, including use in animal models such as rabbits, rats, and mice for preclinical study.
Interested in licensing this patent?