JP2014069038A5

JP2014069038A5 -

Info

Publication number: JP2014069038A5
Application number: JP2012220205A
Authority: JP
Filing date: 2012-10-02
Publication date: 2015-11-19
Anticipated expiration: 2032-10-02

Description

磁気共鳴イメージング(Magnetic Resonance Imaging;以下MRIと略記する)装置は、被検体、特に人体の組織を構成する原子核スピンが発生するNMR信号を計測し、その頭部、腹部、四肢等の形態や機能を2次元的に或いは3次元的に画像化する装置である。撮影において、NMR信号には、傾斜磁場によって異なる位相エンコード、周波数エンコードが付与される。計測されたNMR信号は、2次元又は3次元フーリエ変換されることにより画像に再構成される。
Magnetic Resonance Imaging (hereinafter abbreviated as MRI) equipment measures the NMR signals generated by the nuclear spins that make up the tissue of a subject, especially the human body, and forms and functions of the head, abdomen, limbs, etc. Is a device for imaging in two dimensions or three dimensions. Shooting smell Te, the NMR signal, different phase encoding by the gradient magnetic field, frequency encoding is applied. The measured NMR signal is reconstructed into an image by two-dimensional or three-dimensional Fourier transform.

(実施例1の機能)
最初に、本実施例1の0次位相補正を介した多チャンネル画像合成方法を実現するための演算処理部114の各機能を、図2に示す機能ブロック図に基づいて説明する。本実施例1に係る演算処理部114は、エコーデータ取得部201と、フーリエ変換部202と、ピーク位置検出部203と、0次位相算出部204と、0次位相減算部205と、画像合成部206と、強度補正部207と、を有して成る。なお、ピーク位置検出部203と、0次位相算出部204と、0次位相減算部205とを纏めて位相補正部211ともいう。
(Function of Example 1)
First, each function of the arithmetic processing unit 114 for realizing the multi-channel image composition method through the 0th-order phase correction of the first embodiment will be described based on the functional block diagram shown in FIG. The arithmetic processing unit 114 according to the first embodiment includes an echo data acquisition unit 201, a Fourier transform unit 202, a peak position detection unit 203, a 0th order phase calculation unit 204, a 0th order phase subtraction unit 205, and an image synthesis A unit 206 and an intensity correction unit 207 are provided. The peak position detection unit 203, the 0th-order phase calculation unit 204, and the 0th-order phase subtraction unit 205 are collectively referred to as a phase correction unit 211.

ステップ307で、画像合成部205は、ステップ305で作成された各チャンネルの0次位相減算後画像データを全て複素加算する。複素加算の詳細は前述したとおりである。
ステップ308で、強度補正部207は、ステップ307で作成された複素加算画像データに対して、必要に応じて前述の強度補正処理を行う。強度補正処理の詳細は前述したとおりである。
以上までが本実施例1の多チャンネル画像合成方法の処理フローの概要である。
In step 307, the image composition unit 205 performs complex addition on all the 0th-order phase-subtracted image data of each channel created in step 305 . Details of the complex addition are as described above.
In step 308, the intensity correction unit 207 performs the above-described intensity correction process on the complex addition image data created in step 307 as necessary. The details of the intensity correction processing are as described above.
The above is the outline of the processing flow of the multi-channel image composition method of the first embodiment.

ステップ801で、レベル補正部711は、各チャンネルの0次位相と、ピークレベル係数と、ノイズレベル係数と、を算出、算出したこれらの値803をメモリー113に保存する。本ステップの処理の詳細は後述する。
In step 801, the level correction unit 711 calculates the zero-order phase, peak level coefficient, and noise level coefficient of each channel, and stores the calculated values 803 in the memory 113. Details of the processing in this step will be described later.

Claims

A Fourier transform unit for acquiring complex image data for each channel from k-space data measured by the RF receiver coil of each channel constituting the multi-channel RF receiver coil;
A phase correction unit for correcting the phase of the complex image data for each channel;
An image synthesizing unit that synthesizes complex image data for each phase-corrected channel;
A magnetic resonance imaging apparatus comprising:
The phase correction unit subtracts the zero-order phase of the complex image data for each channel from the complex image data for each channel,
The magnetic resonance imaging apparatus, wherein the image synthesis unit synthesizes complex image data for each channel from which the zeroth-order phase is subtracted.

The magnetic resonance imaging apparatus according to claim 1, wherein the phase correction unit includes:
A peak position detector for detecting a peak position where the signal intensity of the k-space data for each channel is maximum;
A zero-order phase calculation unit that calculates the phase of the peak position as the zero-order phase;
A zero-order phase subtracting unit for subtracting the zero-order phase for each channel from the complex image data for each channel;
A magnetic resonance imaging apparatus comprising:

The magnetic resonance imaging apparatus according to claim 1 or 2,
A magnetic resonance imaging apparatus comprising: a level correction unit that corrects a signal intensity level and a noise level of complex image data for each channel.

The magnetic resonance imaging apparatus according to claim 3, wherein the level correction unit includes:
A peak position intensity calculation unit for calculating the signal intensity at the peak position where the signal intensity of the k-space data of each channel is maximum;
A noise position intensity calculation unit for calculating the signal intensity of the noise position of the k-space data of each channel;
A noise level coefficient calculation unit that calculates a noise level coefficient for each channel using the signal intensity at the noise position of each channel;
A peak level coefficient calculating unit that calculates a peak level coefficient using the signal intensity of the peak position and the signal intensity of the noise position;
A level coefficient multiplier for multiplying the noise level coefficient and the peak level coefficient by complex image data for each channel from which the zeroth-order phase has been subtracted;
A magnetic resonance imaging apparatus comprising:

In the magnetic resonance imaging apparatus according to any one of claims 1 to 4, in multi-slice multi-echo measurement,
The phase correction unit calculates a 0th-order phase for all slices for multi-slices and only for the first echo for multi-echoes, and calculates the 0th-order phase calculated for each slice from complex image data of all echoes of the slices. A magnetic resonance imaging apparatus characterized by subtracting each.

A Fourier transform step of acquiring complex image data for each channel from k-space data measured by the RF receiver coil of each channel constituting the multi-channel RF receiver coil;
A phase correction step for correcting the phase of each complex image data for each channel;
An image synthesizing step for synthesizing complex image data for each phase-corrected channel;
A multi-channel image synthesis method in a magnetic resonance imaging apparatus comprising:
The phase correction step subtracts the zero-order phase of the complex image data for each channel from the complex image data for each channel,
The multi-channel image synthesizing method, wherein the image synthesizing step synthesizes complex image data for each channel from which the zero-order phase is subtracted.