Hitachi, Ltd.

Takashi Onodera

Hideki Kohno

Shigeru Matsui

Etsuji Yamamoto

Hidemi Shiono

Kensuke Sekihara

Hideaki Nakane

Masao Yabusaki

Yukiko Ogura

A nuclear magnetic resonance multi-echo imaging method and an apparatus therefor in which gradient field pulses having predetermined products of intensity and time are applied on both sides of an inversion pulse in at least two of three directions which are orthogonal to each other to dephase components of a magnetization vector which leads to an artifact signal and an error signal, whereby only a normal echo signal can be sampled to form a correct image.

Nuclear magnetic resonance multi-echo imaging method and apparatus

In an NMR imaging method of distinguishing two chemical shifts of unclear spins and obtaining respective spin distribution images, 180.degree. RF. pulses are applied twice to generate two spin echoes after spins of an object for inspection have been exicted. In the second echo among them, a pulse time-interval is so set that the time difference between the Hahn echo and the gradient echo may provide two chemical shifts with a phase difference of 2n.pi.. On the basis of information representing the distribution of a static magnetic field included in an image obtained from the second pulse, an image obtained from the first echo is compensated. By using the compensated image, spin distribution images with two chemical shifts distinguished are obtained.

NMR chemical shift imaging method with influence of intensity

An NMR spectroscopic imaging method of obtaining separate spin distribution images for respective spectral components of the spectrum of an NMR signal caused by the chemical shift of nuclides of interest in an object includes providing for a transversal magnetization signal of the object placed in a static magnetic field. A position of the signal in a phase domain is translated in a K-space from the origin thereof. Further, the signal is sampled while rotating a position of the signal in the K-space plural times on a certain circle in the K-space by applying a rotating field gradient, thereby to obtain a group of signal data. Signal data trains each of which is composed of signal data present at the same position on the K-space in the signal data group obtained by the sampling during the plural signal rotations, is subjected to Fourier transformations, respectively, thereby effecting a spectral analysis of the NMR signal.

High speed NMR spectroscopic imaging method

Disclosed in a nuclear magnetic resonance (NMR) based inspection apparatus using an SQUID flux meter for detecting a small NMR signal, in which a receiving coil for receiving the NMR signal from an object is connected to a mixer, which mixes a reference high-frequency signal with the NMR signal so that the NMR signal is reduced to a low-frequency signal having a differential component of frequencies of both signals, and the low-frequency signal is applied to the input coil of the SQUID flux meter so that it is converted into a voltage signal. The mixer circuit includes Schottky diodes operative at a liquid helium temperature or Josephson junctions, and the portions of apparatus from the reception coil up to the SQUID flux meter are operated in a superconductive state at a liquid helium temperature.

Inspection apparatus based on nuclear magnetic resonance

Method for measuring the time dependence of an oscillating field gradient and representatively its integral function with respect to time for imaging method using the field gradient such as rapid chemical shift imaging method echo planar method, etc. A uniform specimen is placed within a coil of an NMR device, in which nuclear spins are excited; a phase encoding field gradient is applied thereto; and signals are sampled under application of the field gradient to be measured. These steps are repeated and an integral function of the field gradient with respect to time is obtained by using the peak position in the series of data obtained by this repetition.

Method for measuring the time dependence of the field gradient in an NMR

An Alderman high-frequency coil used for generating or detecting a high-frequency magnetic field in an NMR apparatus comprises two ring-shaped inner conductors aligned coaxially with a spacing being made therebetween and two outer conductors disposed to surround the inner conductors. The outer conductors are each split along the current path to form a 4-piece outer conductor.

High-frequency coil for nuclear magnetic resonator

An NMR imaging method which provides a three-dimensional image representative of the two-dimensional distribution of nuclear spin species resolved by chemical shift or the local spectra resolved by two-dimensional location. After the excitation of nuclear spins and the phase-encoding by application of a field gradient G.sub.y, a periodically inverting field gradient G.sub.x is generated to yield a continuous echo train. The echo train is sampled and separated into data of odd-numbered echoes and data of even-numbered echoes which data are in turn reconstructed into two-dimensional data arrays, respectively. The data thus reconstructed are three-dimensional Fourier-transformed.

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Koganei, Japan

Takashi Onodera