The use of gas as a contrast medium has significant potential to avoid limitations of conventional contrast agents. Gases can transit smaller vascular conduits and can be injected through smaller and less traumatic access systems than liquids. Highly soluble gases (such as CO2) can be imaged as a bolus. Blood is displaced by the gas, with the result of negative image contrast.
Because gases are compressible, standard liquid injectors cannot be used. The design for a gasinjector should have the option for individual adaptation of blood flow rate, vessel diameter, pulse pressure, and heart rate.

From Siemens Medical Systems;
Received FDA clearance in 2012.
The MAGNETOM Spectra is a cost-optimized high field MRI system with Tim 4G and Dot technologies. The system consumes less energy compared to other 3 Tesla scanners. The magnet-cooling helium is contained in a closed loop, which prevents the gas from escaping and reduces the need for refills. TimTX includes innovative techniques in the radio frequency excitation hardware as well as new application and processing features enabling uniform RF distribution in all body regions.

Pharmacyclics is a pharmaceutical company developing novel agents to improve current therapeutic approaches to cancer, cardiovascular diseases, and inflammation. The company's proprietary products are derived from its core technology in biometallic chemistry. These products under development are based upon small molecules, which bind metals in a unique way and are capable of capturing and focusing forms of energy used in a variety of medical applications. The company has one product in registration with the FDA, Gadolite® Oral Suspension, a contrast agent for imaging the gastrointestinal tract; two products in clinical development, Gd-Tex (Motexafin gadolinium), a radiation sensitizer, Lu-Tex, a photosensitizer; and several compounds in preclinical development.

MRI Contrast Agents:

General MRI of the abdomen can consist of T1 or T2 weighted spin echo, fast spin echo (FSE, TSE) or gradient echo sequences with fat suppression and contrast enhanced MRI techniques. The examined organs include liver, pancreas, spleen, kidneys, adrenals as well as parts of the stomach and intestine (see also gastrointestinal imaging). Respiratory compensation and breath hold imaging is mandatory for a good image quality.
T1 weighted sequences are more sensitive for lesion detection than T2 weighted sequences at 0.5 T, while higher field strengths (greater than 1.0 T), T2 weighted and spoiled gradient echo sequences are used for focal lesion detection. Gradient echo in phase T1 breath hold can be performed as a dynamic series with the ability to visualize the blood distribution. Phases of contrast enhancement include the capillary or arterial dominant phase for demonstrating hypervascular lesions, in liver imaging the portal venous phase demonstrates the maximum difference between the liver and hypovascular lesions, while the equilibrium phase demonstrates interstitial disbursement for edematous and malignant tissues.
Out of phase gradient echo imaging for the abdomen is a lipid-type tissue sensitive sequence and is useful for the visualization of focal hepatic lesions, fatty liver (see also Dixon), hemochromatosis, adrenal lesions and renal masses. The standards for abdominal MRI vary according to clinical sites based on sequence availability and MRI equipment. Specific abdominal imaging coils and liver-specific contrast agents targeted to the healthy liver tissue improve the detection and localization of lesions.
See also Hepatobiliary Contrast Agents, Reticuloendothelial Contrast Agents, and Oral Contrast Agents.

For Ultrasound Imaging (USI) see Abdominal Ultrasound at Medical-Ultrasound-Imaging.com.