JP2001112735A5

JP2001112735A5 -

Info

Publication number: JP2001112735A5
Application number: JP1999296572A
Authority: JP
Filing date: 1999-10-19
Publication date: 2006-12-07
Anticipated expiration: 2019-10-19

Description

【特許請求の範囲】
【請求項１】
被検体に高周波パルスを照射する手段と、読み出し傾斜磁場パルスを印加する手段と、位相エンコード傾斜磁場パルスを印加する手段と、少なくとも１回の繰り返し時間内で発生するエコー信号を時系列的に検出する手段と、エコー信号から画像を作成し、表示する手段と、所定のパルスシーケンスに従い前記各手段を制御する制御手段とを有する磁気共鳴イメージング装置において、
前記制御手段は、位相エンコード傾斜磁場パルスを印加せずに少なくとも１回の繰り返し時間内で計測した前計測エコー信号から得られる該前計測エコーの位相情報を用いて本計測エコー信号を取得するためのパルスシーケンスのエコー計測時間を調整する手段を備えたことを特徴とする磁気共鳴イメージング装置。
【請求項２】
被検体に高周波パルスを照射する手段と、読み出し傾斜磁場パルスを印加する手段と、位相エンコード傾斜磁場パルスを印加する手段と、少なくとも１回の繰り返し時間内で発生するエコー信号を時系列的に検出する手段と、エコー信号から画像を作成し、表示する手段と、所定のパルスシーケンスに従い前記各手段を制御する制御手段とを有する磁気共鳴イメージング装置において、
前記制御手段は、位相エンコード傾斜磁場パルスを印加せずに少なくとも１回の繰り返し時間内で連続的に計測した前計測エコー信号から、各前計測エコー信号間の位相変化をそれぞれ算出し、少なくとも１回の繰り返し時間内で連続的に計測した本計測エコー信号を、対応する前記位相変化の情報を用いて補正する手段を有する磁気共鳴イメージング装置。
【請求項３】
請求項２に記載の磁気共鳴イメージング装置において、
前記制御手段は、位相エンコードを印加しない前計測シーケンスの後に位相エンコードを付加した本計測シーケンスを実行するよう制御し、
前記補正する手段は、計測空間上に時系列に配置される本計測エコー信号を対応する前記位相変化の情報に基づいて、偶数番目取得の本計測エコー信号の位相を奇数番目取得の本計測エコー信号の位相に揃える、奇数番目取得の本計測エコー信号の位相を偶数番目取得の本計測エコー信号の位相に揃える、もしくは計測中心の位相に揃える、のいずれかの処理を実行することを特徴とする磁気共鳴イメージング装置。 [Claims]
[Claim 1]
A means for irradiating a subject with a high-frequency pulse, a means for applying a read gradient magnetic field pulse, a means for applying a phase-encoded gradient magnetic field pulse, and an echo signal generated within at least one repetition time are detected in time series. In a magnetic resonance imaging apparatus having means for performing the method, means for creating and displaying an image from an echo signal, and control means for controlling each of the means according to a predetermined pulse sequence.
The control means acquires the present measurement echo signal by using the phase information of the pre-measurement echo obtained from the pre-measurement echo signal measured within at least one repetition time without applying the phase-encoded gradient magnetic field pulse. A magnetic resonance imaging apparatus provided with a means for adjusting the echo measurement time of the pulse sequence of the above.
2.
A means for irradiating a subject with a high-frequency pulse, a means for applying a read gradient magnetic field pulse, a means for applying a phase-encoded gradient magnetic field pulse, and an echo signal generated within at least one repetition time are detected in time series. In a magnetic resonance imaging apparatus having means for performing the method, means for creating and displaying an image from an echo signal, and control means for controlling each of the means according to a predetermined pulse sequence.
The control means calculates the phase change between each pre-measurement echo signal from the pre-measurement echo signals continuously measured within at least one repetition time without applying a phase-encoded gradient magnetic field pulse, and at least 1 A magnetic resonance imaging apparatus having means for correcting the measurement echo signal continuously measured within a repetition time of times by using the corresponding phase change information.
3.
In the magnetic resonance imaging apparatus according to claim 2.
The control means controls to execute the present measurement sequence in which the phase encoding is added after the pre-measurement sequence in which the phase encoding is not applied.
The correction means is based on the phase change information corresponding to the measurement echo signals arranged in time series on the measurement space, and the phase of the measurement echo signal acquired in the even order is acquired in the odd order. It is characterized by executing either processing of aligning with the phase of the signal, aligning the phase of the measured echo signal with the odd-th acquisition with the phase of the main measurement echo signal with the even-th acquisition, or aligning with the phase of the measurement center. Magnetic resonance imaging device.