Method and system for motion compensation in magnetic resonance (MR) imaging
View Patent ↗A method and system are provided for imaging by predicting, from multiple real time MR imaging data, motion of an object and subsequently obtaining high-resolution imaging data of the object using the predicted motion of the object. Thus, the process uses real time images to derive a history of the motion of the object and thereby generate a predicted trajectory of the object and then uses this trajectory to determine the projected position of the object during a subsequent, separate, high-resolution data acquisition phase.
1. A method for MR imaging, comprising:
acquiring first low-resolution MR image data using an MR scanner during a first heart beat cycle in a pre-scan mode;
measuring real-time motion of a coronary artery based on the acquired first low-resolution MR image data using an image processing device;
building a model of coronary artery motion based on the measured real-time motion of the coronary artery from the acquired first low-resolution MR image data;
tracking a position and predicting a trajectory of the coronary artery within the first particular heart beat cycle that the first low-resolution MR image data was acquired within based on the model of coronary artery motion using a computer system;
predicting a first acquisition window based on the tracked position and predicted trajectory of the coronary artery;
obtaining first high-resolution MR image data of the coronary artery at the predicted first acquisition window within the first particular heart beat cycle;
acquiring second low-resolution MR image data using the MR scanner during a second heart beat cycle;
measuring real-time motion of the coronary artery based on the acquired second low-resolution MR image data using the image processing device;
updating the model of coronary artery motion based on the measured real-time motion of the coronary artery from the acquired second low-resolution MR image data;
tracking a position and predicting a trajectory of the coronary artery within the second particular heart beat cycle based on the updated model of coronary artery motion using a computer system;
predicting a second acquisition window based on the tracked position and predicted trajectory of the coronary artery; and
obtaining second high-resolution MR image data of the coronary artery at the predicted second acquisition window within the second particular heart beat cycle.
2. The method of claim 1 , wherein building the model of coronary artery motion comprises:
separating effects of heart motion from respiratory motion;
assessing beat-to-beat variations in coronary artery motion; and
eliminating outliers.
3. The method of claim 1 , wherein the low-resolution MR image data comprises images of low spatial resolution and moderate temporal resolution, each image acquired in a single short period of between 30 to 50 ms.
4. The method of claim 1 , wherein the method is repeated for a sequence of 8 to 10 heartbeats.
5. The method of claim 1 , wherein the predicted motion of the coronary artery covers a next 100-200 ms from currently detected motion.
6. The method of claim 1 , wherein the coronary artery comprises one of the left anterior descending (LAD), the left circumflex artery (LCX), and the right coronary artery (RCA).
7. The method of claim 1 , wherein real-time motion correction is performed using a tracking algorithm.
8. The method of claim 1 , wherein prior to acquiring the first and second high-resolution MR image data, a determination is made that high resolution data should be acquired based on the predicting a trajectory of the coronary artery and ECG.
9. The method of claim 1 , wherein after acquiring the first and second high-resolution MR image data, a determination is made as to whether to keep the acquired high-resolution MR image data or to reacquire the high-resolution MR image data.