Interactive scan control for kinematic study in open MRI.
OBJECTIVE
A tool to support the subject is generally used for kinematic joint imaging with an open MRI apparatus because of difficulty setting the image plane correctly. However, use of a support tool requires a complicated procedure to position the subject, and setting the image plane when the joint angle changes is time consuming. Allowing the subject to move freely enables better diagnoses when kinematic joint imaging is performed. We therefore developed an interactive scan control (ISC) to facilitate the easy, quick, and accurate setting of the image plane even when a support tool is not used.


METHODS
We used a 0.4T magnetic resonance (MR) imaging system open in the horizontal direction. The ISC determines the image plane interactively on the basis of fluoroscopy images displayed on a user interface. The imaging pulse is a balanced steady-state acquisition with rewound gradient echo (SARGE) sequence with update time less than 2 s. Without using a tool to support the knee, we positioned the knee of a healthy volunteer at 4 different joint angles and set the image plane through the patella and femur at each of the angles. Lumbar imaging is also demonstrated with ISC.


RESULTS
Setting the image plane was easy and quick at all knee angles, and images obtained clearly showed the patella and femur. Total imaging time was less than 10 min, a fourth of the time needed when a support tool is used. We also used our ISC in kinematic imaging of the lumbar.


CONCLUSIONS
The ISC shortens total time for kinematic joint imaging, and because a support tool is not needed, imaging can be done more freely in an open MR imaging apparatus.
Goto
Tomohiro
T
Application Development Department MRI System Division, Hitachi Medical Corporation, Kashiwa, Chiba, Japan. goto-tomohiro@rd.hitachi-medical.co.jp
Hamada
Kiyomi
K
Ito
Taeko
T
Nagao
Hisako
H
Takahashi
Tetsuhiko
T
Hayashida
Yoshiko
Y
Hiai
Yasuhiro
Y
Yamashita
Yasuyuki
Y
D001696:Biomechanical Phenomena; D005471:Fluoroscopy; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011187:Posture