Method and apparatus for examination by nuclear magnetic resonance

An examination method utilizing a nuclear magnetic resonance technique in which the body of a subject to be examined is placed in an uniform static magnetic field and subjected to an electromagnetic wave having a frequency which induces nuclear magnetic resonance, a magnetic field is also applied to the subject body to specify an area of the body from which nuclear magnetic resonance (NMR) signals are radiated, and such nuclear magnetic resonance signals from the specified body area are received, the method comprising the steps of:

• applying a 180.degree. pulse as the electromagnetic wave to the body;
• applying a 90.degree. pulse to the body to excite the same a predetermined time interval after the 180.degree. pulse has been applied;
• then applying a 180.degree. pulse to the body to produce an echo signal;
• applying a 90.degree. signal again to the body when said echo signal is maximum to thereby allow a magnetization to return to a state of thermal equilibrium;
• thereafter repeating the foregoing sequence of the steps at prescribed intervals;
• and
• effecting prescribed arithmetic operations on NMR signals obtained in the respective sequences for thereby producing a T.sub.1 image.

An examination apparatus utilizing a nuclear magnetic resonance technique, comprising:

• means for applying a uniform static magnetic field to the body of a subject;
• means for producing magnetic fields to specify an area of the body from which a nuclear magnetic resonance (NMR) signal is to be radiated;
• excitation means for applying electromagnetic pulses to the body;
• control means for controlling signals to be fed to said excitation means;
• means for detecting the NMR signal from the body;
• arithmetic means for processing signals from said detecting means and effecting arithmetic operations on the signals to obtain a body-section image;
• and
• said control means being operable by applying a first 90.degree. pulse as the electromagnetic wave to the body to excite the same, then applying a 180.degree. pulse to the body to produce an echo signal, applying a second 90.degree. pulse to the body when said echo signal is maximum to thereby allow a magnetization to return to a state of thermal equilibrium, and thereafter repeating the foregoing sequence of the steps at prescribed intervals.