Hitachi, Ltd.

Hitachi Medical Corporation

Tatsuo Nozokido

Etsuji Yamamoto

Hideki Kohno

Hiroyuki Takeuchi

Chikako Nakamura

A method for correcting phase errors in a nuclear magnetic resonance signal is disclosed, by which central frequencies of NMR signals are measured directly before and directly after or in addition in a course of a normal measurement for obtaining an NMR signal for imaging and an amount of phase error is obtained for each of the NMR signals for imaging by using a difference between the central frequencies and a measurement time for each of the NMR signals for imaging.

Method for correcting phase errors in a nuclear magnetic resonance

A multi-echo NMR imaging method of obtaining images separated from each other with respect to two kinds of chemical shifts, typically, a fat image and a water image, includes performing the measurement of an object to be examined through a multi-echo sequence in which phase differences of .theta..sub.1 .noteq.n.pi. and .theta..sub.2 =2n.pi. (n=.+-.1, .+-.2, ---) are respectively produced for first and second echoes between two kinds of spins to be separated from each other, deriving first and second complex images of the object from the first and second echoes, respectively, performing the measurement of a phantom exhibiting one of the chemical shifts through the multi-echo sequence and deriving third and fourth complex images of the phantom, eliminating phase errors due to a static magnetic field inhomogeneity from the first and second images using phase data of the third and fourth images respectively, and eliminating phase error due to a magnetic permeability distribution to the object.

Multi-echo NMR imaging method

A testing method and apparatus by use of nuclear magnetic resonance measure, at timings influenced and not influenced from chemical shift, nuclear magnetic resonance signals taken from a sample to be tested at least one of whose values of permeability and chemical shift is known and a reference sample both of whose values of permeability and chemical shift and their spatial distribution are uniform thereby to acquire four items of image vector information. Further, the testing method and apparatus take phase differences between the items of image vector information to separately extract the phase component influenced by the permeability distribution and the phase component influenced from the chemical shift.

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Kokubunji, Japan

Tatsuo Nozokido