The brain: integrated three-dimensional display of MR and PET images
Patients being evaluated for neurologic symptoms may have both magnetic resonance (MR) and positron emission tomography (PET) imaging procedures in the development of a diagnosis as well as the planning and initiation of treatment. The information provided by the two imaging procedures is complementary; MR images offer excellent anatomical pictures of the brain, and PET images supply data on local brain function, such as metabolism or blood flow. By applying a new three-dimensional (3D) technique researchers were able to integrate MR and PET images into a computerized 3D image of the brain. This integration of MR and PET provided a noninvasive method for detecting metabolic abnormalities with respect to anatomy in three patients with intractable epilepsy (two with brain tumors and one with encephalitis). The accuracy of the 3D images was confirmed intraoperatively by means of inspection of the brain surface and electroencephalographic (recording the electrical impulses of the brain) mapping. The integration of MR and PET in a 3D model provided a more informative picture of the brain than a single-modality image. This technique may become valuable in interpreting PET studies of epileptic patients, symptomatic patients who have normal MR anatomy and may also become a valuable tool for neurosurgical planning and treatment.
Publication Name: Radiology
Mediastinal histoplasmosis granuloma: evaluation with CT
Histoplasma capsulatum, a parasitic fungus found predominantly in soil in the central US, is a well-known cause of disease of the mediastinum (the mass of organs and tissues separating the lungs) and hilus (root of the lungs). Histoplasmosis, the infection caused by this fungus, may result in fatigue, weight loss, fever, frontal headaches, chest wall and abdominal pain, and blood-streaked sputum. Histoplasmosis is believed to be the most common cause of fibrosing (fiber forming) inflammation of the mediastinum and may indicate an abnormality of the immune (disease fighting) system. Researchers discuss three cases in which computed tomography (CT) scans revealed mediastinal granulomas (growths or tumors of lymphoid cells) due to histoplasmosis. Alternative diagnoses of illnesses which cause granulomas that may have a similar appearance on CT are described. These include: tuberculosis, lymphoma, sarcoidosis and metastatic lung cancer. None of the three cases in this study demonstrated calcification around the site of the granuloma, but the presence of calcification should be carefully evaluated since it supports the diagnosis of granulomatous infection.
Publication Name: Radiology
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