protocol and positioning
Integrated Panoramic CP Array Coils Streamline Patient Imaging
Protocol supplied by Andrew W. Litt, MD, NYU Medical Center, New York
When imaging a number of patients throughout the day at large radiology facilities, radiologists and technologists must constantly readjust the settings for each patient when the magnetic resonance (MR) unit is used. Should a patient require a series of different images, the head, neck, and spine, for example, the system has to be reconfigured for each position.
By combining CP array coils into a sophisticated integrated panoramic coil design, productivity (patient throughput) is increased, anatomical coverage is expanded, and examination times are streamlined–all of which contribute to increased clinical efficiency.
The MR imaging division at NYU Medical Center has been using Siemens’ MAGNETOM Symphony Integrated Panoramic Array™ Coils for about one year. The system allows radiologists to image patients panoramically, from head to thigh, using multiple CP array coils that can be used simultaneously without repositioning the patient.
Andrew W. Litt, M.D., vice chairman, department of radiology and director, Neuro MRI, noted that the unit has been used to image some 2000 patients to date. “The coils,” he said, “are extremely useful in doing multiple MRI exams on patients, and save imaging time since the patient generally stays in the same position. Usually, only the table is moved or a new coil is selected via software control.”
According to Dr. Litt, some approximate time savings seen at his facility were: brain/neck MRI/A exams, 5 mins. to 7 mins.; neck MRA/Aortic arch exams, 30 mins.; ABD/Pelvis with and without GADO, 10 mins.; spinal cord study or CT spine, 10 mins; complete spine/brain (especially on drop METS study to same time and contrast (GADO), 10 mins. to 15 mins.; leg/spine/hips, 7 mins. to 10 mins.
Up to four coils can be positioned on the table simultaneously, and the technologist can select either an individual coil or choose a combination of coils to be used simultaneously. Previously, only coils in use were placed on the table and were changed for every patient or examination. By not having to change coils for each patient or between patients, significant time savings can be achieved, particularly in busy MRI facilities.
To increase patient throughput and reduce set up, the lower section of the CP head array coil and the whole CP spine array coil are integrated into the patient table. The coils remain on the table for almost all examinations except breast imaging. Up to four coils can be placed on the patient or table, largely eliminating patient and coil repositioning. For example, when switching from spine to body examinations, the technologist simply selects the body array in combination with the spine array via the computer and does not have to physically change the actual coils on the table.
The increased flexibility for large field of view imaging helps facilitate head/neck imaging, whole spine examinations, body screening and peripheral MR angiography.
Currently, there are four different solutions on the market for the technical implementation of phased-array coils. These emphasize different aspects in clinical application as well as in technical realization. Siemens’ approach involves four high-speed CP channels; up to four CP elements of one or multiple phased array coils can be activated.
Each element has its own channel to the image reconstruction. All channels are identical and provide high-speed data transfer for EPI (Echo Planar Imaging) applications.
Siemens supports all clinical examinations with no restrictions in terms of speed or SNR (signal-to-noise ratio). An ad-vanced array option further increases one’s ability to freely combine coils by allowing the combination of up to eight coil elements to be used simultaneously.