Kirk L. Moon

Enhanced MRI of tumors utilizing a new nitroxyl spin label contrast agent

Nitroxyl spin labels have been shown to be effective in vivo contrast agents for magnetic resonance imaging (MRI) of the central nervous system, myocardium, and urinary tract. A new pyrrolidine nitroxyl contrast agent (PCA) with better resistance to in vivo metabolic inactivation than previously tested agents was studied for its potential to enhance subcutaneous neoplasms in an animal model. Twenty-two contrast enhancement trials were performed on a total of 15 animals 4-6 weeks after implantation with human renal adenocarcinoma. Spin echo imaging was performed using a .35 T animal imager before and after intravenous administration of PCA in doses ranging from 0.5 to 3mM/kg. The intensity of tumor tissue in the images increased an average of 35% in animals receiving a dose of 3 mM/kg. The average enhancement with smaller doses was proportionately less. Tumor intensity reached a maximum within 15 min of injection. The average intensity difference between tumor and adjacent skeletal muscle more than doubled following administration of 3 mM/kg of PCA. Well-perfused tumor tissue was more intensely enhanced than adjacent poorly perfused and necrotic tissue.

Nuclear Magnetic Resonance Imaging of the Temporomandibular Joint: Preliminary Observations

AbstractMagnetic resonance imaging (MRI) is a new technique used by radiologists to give images of the body in a manner similar to that of computed tomography (CT). This is done without ionizing radiation, and the technique has no known biological aftereffects. MRI promises to replace CT scanning in the diagnosis of many disorders throughout the body. We feel that it has the potential to replace arthrography and CT in diagnosing internal derangements of the temporomandibular joint. This report briefly explains the principles of MRI and describes our initial experience in obtaining images of the disk of the temporomandibular joint.

Magnetic Resonance Imaging: Skeletal Applications

It has been assumed that magnetic resonance imaging (MRI) would have limited utility in visualizing bones, due to the lack of hydrogen atoms in cortical bone. Nonetheless, that same lack makes it possible to clearly distinguish cortical bone from soft tissue and from marrow. Thus, roles are described for magnetic resonance imaging in depicting bone and soft tissue tumors, the spine (including the spinal cord and vertebral discs), and appendicular soft tissue, as well as the detection of avascular necrosis in the hip.