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Method and apparatus for identifying at least one material comprised in a voxel

Verfahren und Vorrichtung zur Identifizierung von mindestens einem Material in einem Voxel
 
: Blaimer, Martin; Jakob, Peter

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Frontpage ()

EP 3385742 A1: 20170405
English
Patent, Electronic Publication
Fraunhofer IIS ()

Abstract
The present invention discloses a method (500) for identifying at least one material (115) comprised in a voxel (120). The disclosed MR data acquisition method uses the transient phase of balanced steady-state free precession (bSSFP), which allows to simultaneously acquire quantitative information about longitudinal and transversal relaxation times T1 and T2 and relative proton density in multi-component systems. In one embodiment , these values are derived by combining signals from multiple acquisitions each of whom being realized by radio-frequency excitation pulses with different flip angles.The method is thus suitable for quantitative MRI T1 and T2 mapping. The method comprises a step of Reading in (510) at least a first (S 1 ) and a second (S 2 ) signal train, the first (S 1 ) and second (S 2 ) signal train each representing magnetization values being determined after the material (115) in the voxel (120) was exposed to predefined radio-frequency pulses (P 1 , P 2 ), wherein the predefined radio-frequency pulses (P 1 ) exposed to the material (115) in the voxel (120) before or during measuring the first signal train (S 1 ) differs in at least one parameter (±) from the radio-frequency pulses (P 2 ) exposed to the material (115) in the voxel (120) before or during measuring the second signal train (S 2 ). Furthermore, the method comprises a step of Performing (520) at least a time-domain-frequency-domain transformation, such as e.g. inverse Laplace transformation, in order to obtain a first (F 1 ) and a second (F 0 ) transformation value, the first transformation value (F 1 ) representing a frequency domain signal resulting from the time-domain-frequency-domain transformation on the basis of at least the first signal train (S 1 ) and the second transformation value (F 0 ) representing a frequency domain signal resulting from the time-domain-frequency-domain transformation on the basis of at least the second signal train (S 2 ). Finally the method comprises a step of Specifying (530) the material (115) using the first (F 1 ) and second (F 0 ) transformation values or values derived from the first (F 1 ) and/or second (F 0 ) transformation value, in order to identify the material (115).

: http://publica.fraunhofer.de/documents/N-530955.html