Search results for "Positive contrast"
showing 2 items of 2 documents
Gradient-echo and CRAZED imaging for minute detection of Alzheimer plaques in an APPV717I x ADAM10-dn mouse model.
2007
Different strategies to visualize amyloid plaques with MRI at 17.6 Tesla were investigated in a novel mouse model of Alzheimer's disease (AD). Large iron-containing plaques were observed in the thalamus, but cortical plaques did not show iron deposits. Plaques in the thalamus were visualized in vivo with the use of low-resolution, 3D gradient-echo (GRE) imaging in 82 s, and with 94-microm resolution in 34 min. The feasibility of obtaining bright contrast from plaques using the COSY revamped with asymmetric z-GRE detection (CRAZED) technique was investigated in experiments on fixed brains. The original CRAZED approach provided reduced signal near the plaques (similarly to GRE imaging) and ad…
Zur Frage der Darmkontrastierung in der abdominellen Computertomographie
1992
In 56 patients undergoing abdominal CT the gastrointestinal tract was defined by negative contrast instead of the conventional positive contrast from an iodine containing contrast medium. The contrast material was a 2 1/2% mannitol solution and was used for filling the rectum. Filling of the gastrointestinal tract was of similar quality to that obtained with positive contrast media. The number of artifacts due to high contrast boundaries was slightly greater with the negative contrast than it would have been with positive contrast. Differentiation of the gastrointestinal tract from other abdominal organs was equally good for both methods. The negative contrast method was poor in diagnosing …