Slew of new MRI systems boost speed, slash scan times

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Faster scan times, faster image processing and more automated scan options on new and upgraded MRI scanners were on display around the exhibit floor at RSNA 2003. The focus continues on 1.5T scanners, while greater functionality is migrating up to 3.0T units and down to open systems as well.


GE Medical Systems used RSNA as the springboard to launch three new imaging techniques for its EXCITE technology for Signa MR systems for optimizing neuroradiology, angiography and breast imaging. Propeller imaging for brain studies, TRICKS contrast-enhanced angiography and VIBRANT bilateral breast imaging provide boosts in image quality, tissue differentiation and scan times, GE said. EXCITE, which debuted last year at RSNA, allows GE MRI scanners to transfer, receive and process imaging data far more quickly than previous systems.

 Propeller technology creates T2-weighted and diffusion-weighted brain images, improving contrast-to-noise ratio by 20 to 30 percent, reducing tissue-to-air image distortions in diffusion-weighted imaging and reduces the problem of patient motion by allowing good images despite patient twitches, jerks or "sightseeing," when a patient looks around the gantry. Propeller accounts for these movements, creating crisp, usable images.

 TRICKS (Time Resolved Imaging of Contrast Kinetics) data acquisition for MR angiography requires about 10 times the data volume and 12 times the data processing power of conventional methods, GE said. The method works by collecting one image of the static background, then adds a rapid series of only the dynamic components of the image (which is key to high temporal resolution). The final result is an integration of the background and dynamic information, in a clinically practice timeframe. In contrast-enhanced magnetic resonance angiography (MRA) of the legs, TRICKS eliminates timing and triggering, allowing a point-and-shoot application. Physicians say TRICKS speeds exam time by relieving the need for stepping table runoffs. They use TRICKS to do the third station and second station. Also, no time-of-flight exam is necessary to determine arteries from veins.

 VIBRANT (Volume Imaged Breast Assessment) imaging provides simultaneous, high resolution bilateral breast imaging with a single injection in the sagittal plane (which is preferred by mammographers). The field of view is also smaller. GE said it provides similar resolution to a single-breast MR exam with no scan time penalty. VIBRANT also includes bilateral shimming for each patient, breast-specific spectral inversion and automated image subtraction for fast suppression. The technology can be a time-saver, opening up one exam time slot to another patient, since it allows the imaging of both breasts simultaneously, rather than the previous method of scanning one breast in the morning, waiting four hours for the gadolinium to wash out and then imaging the other breast. The feature has been shipping since September.

 GE debuted EXCITE technology in 2002 to improve signal-to-noise ratio (SNR), resolution and speed. At RSNA, the company also announced the migration of EXCITE to the 0.7 T Signa OpenSpeed system. EXCITE is upgradeable to the installed base of OpenSpeed systems. Gurney Radiology in Illnois is the first working site.

 GE also highlighted the Signa Excite 3.0T 3-tesla MRI scanner at the show, which was introduced in 2003. The scanner's Perform feature enables users to monitor power deposition in the patient over time, helping users avoid sequences that might exceed guidelines on specific absorption rates (SAR) -- which is common in 3-tesla scanning. The company has installed five Signa Excite 3.0Ts and expected to shipped 15 by the end of 2003.


Siemens Medical Solutions at RSNA announced the first installation of the MAGNETOM Avanto 1.5 Tesla MR system, which is the first product to incorporate Siemens Total imaging matrix (Tim) technology, at New York University (NYU) Medical Center. Tim uses a whole body surface coil concept to combine up to 76 coil elements and 32 RF channels [76x32]. Tim allows the user to select exams, not coils, and provides the highest acquisition speed without image artifacts or restrictions in coverage, giving radiologists the opportunity to conduct advanced applications, such as metastasis evaluation. The Tim Application Suite includes a comprehensive set of clinical applications, including Neuro, Angio, Cardiac, Body, Oncology, Orthopedic, and Pediatric. Siemens MAGNETOM