Truly Hybrid X-Ray/MR Imaging: Toward a Streamlined Clinical System1

Ganguly, Arundhuti; Wen, Zhifei; Daniel, Bruce L.; Butts, Kim; Kee, Stephen T.; Rieke, Viola; Do, Huy M.; Pelc, Norbert J.; Fahrig, Rebecca

doi:10.1016/j.acra.2005.03.076

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Volume 12, Issue 9 , Pages 1167-1177, September 2005

Truly Hybrid X-Ray/MR Imaging: Toward a Streamlined Clinical System¹

Arundhuti Ganguly, PhD
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
- Address correspondence to: A.G.
Zhifei Wen, BS
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
- Department of Physics, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Bruce L. Daniel, MD, PhD
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Kim Butts, PhD
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Stephen T. Kee, MD
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Viola Rieke, MS
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
- Department of Physics, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Huy M. Do, MD
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
- Department of Physics, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Norbert J. Pelc, DSc
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.
Rebecca Fahrig, PhD
- Department of Radiology, Stanford University, Lucas MRS Center, 1201 Pasteur Dr., Stanford, CA 94305.

Received 27 February 2005; received in revised form 30 March 2005; accepted 31 March 2005.

Rationale and Objective

We have installed an improved x-ray/MR (XMR) truly hybrid system with higher imaging signal-to-noise ratio (SNR) and versatility than our first prototype. In our XMR design, a fixed anode x-ray fluoroscopy system is positioned between the two donut-shaped magnetic poles of a 0.5T GE Signa-SP magnet (SP-XMR). This paper describes the methods for increased compatibility between the upgraded x-ray and MR systems that have helped improve patient management.

Materials and Methods

A GE OEC 9800 system (GE OEC Salt Lake City, UT) was specially reconfigured for permitting x-ray fluoroscopy inside the interventional magnet. A higher power x-ray tube, a new permanent tube mounting system, automatic exposure control (AEC), remote controlled collimators, choice of multiple frame rates, DICOM image compatibility, magnetically shimmed x-ray detector, x-ray compatible MR coil, and better RF shielding are the highlights of the new system. A total of 23 clinical procedures have been conducted with SP-XMR guidance of which five were performed using the new system.

Results

The 70% increased power for fluoroscopy, and a new 6 times higher power single frame imaging mode, has improved imaging capability. The choice of multiple imaging frame rates, AEC, and collimator control allow reduction in x-ray exposure to the patient. The DICOM formatting has permitted easy transfer of clinical images over the hospital PACS network. The increased MR compatibility of the detector and the x-ray transparent MR coil has enabled faster switching between x-ray and MR imaging modes.

Conclusion

The improvements introduced in our SP-XMR system have further streamlined x-ray/MR hybrid imaging. Additional clinical procedures could benefit from the new SP-XMR imaging.

Key Words: X-ray fluoroscopy , interventional MRI , truly hybrid imaging , signal to noise ratio , system compatibility