Published in:
01-07-2015 | Technical Note
Evaluation of blood volume by use of blood oxygen level-dependent magnetic resonance imaging in a cuff-compression model: usefulness of calculated echo time image
Authors:
Tatsuya Nishii, Atsushi K. Kono, Mizuho Nishio, Katsusuke Kyotani, Kouya Nishiyama, Kazuro Sugimura
Published in:
Japanese Journal of Radiology
|
Issue 7/2015
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Abstract
Purpose
Separate assessment of changes in blood oxygenation and blood volume is required in blood oxygen level-dependent (BOLD) imaging. We developed a calculated echo time (TE) imaging technique designed to minimize effects of blood oxygenation and to evaluate blood volume specifically.
Materials and methods
Dynamic 3T multi-echo BOLD images of calf muscle were acquired from six healthy volunteers by use of a cuff-compression model. Calculated TE images at TE = 0 ms (cTE0) and \(T_{2}^{ * }\) map (\(T_{2}^{ * }\)) were calculated from acquired multi-echo images. The time courses of the mean value for the entire calf muscles in cTE0, in acquired BOLD images at TE = 45.2 ms (aTE45), and in \(T_{2}^{ * }\) were obtained. The Euclidean distances between the two pairs of time courses were calculated: distance between aTE45 and \(T_{2}^{ * }\) (D
at), and that between cTE0 and \(T_{2}^{ * }\) (D
ct). The difference between D
at and D
ct was tested by use of the Wilcoxon signed rank test.
Results
D
at was significantly different from D
ct (P = 0.031), indicating that the time course of cTE0 was significantly different from that of blood oxygenation-weighted images (\(T_{2}^{ * }\) and aTE45).
Conclusion
The effect of blood oxygenation could be minimized using cTE0. Thus, signal intensity changes of cTE0 reflected changes in blood volume more specifically.