Michael Nelles MD, Presenter: Nothing to Disclose

Roy König, Abstract Co-Author: Nothing to Disclose

Juergen Gieseke DSc, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Horst Urbach MD, Abstract Co-Author: Nothing to Disclose

Hans H. Schild MD, Abstract Co-Author: Nothing to Disclose

Winfried Albert Willinek MD, Abstract Co-Author: Speakers Bureau, Bayer AG Speakers Bureau, Bracco Group Speakers Bureau, General Electric Company Speakers Bureau, Koninklijke Philips Electronics NV Speakers Bureau, Lantheus Medical Imaging, Inc

Prospective intra-individual comparison of single and dual source parallel RF excitation in 3.0T MR imaging (MRI) of the spine.

A 3.0T MR system (Achieva 3.0T TX, Philips Healthcare) equipped with fully flexible multi-source RF transmission (dual source) was used. The root mean square magnitude of RF fields was increased whereas the time of repetition was reduced according to the revised RF setup while maintaining specific energy absorption limitations. 30 patients underwent MRI of the spinal cord. A total of 77 sequences with and without parallel transmission were available for an intraindividual comparison. Diagnostic quality of examinations was scored as follows: Score of 4, excellent (sharp depiction of vertebrae, the thecal sac and traversing nerve roots). Score of 3, adequate for diagnosis (minor artifacts (e.g. CSF pulsation), or noise present not interfering with image interpretation). Score of 2, questionable for diagnosis (impaired by artifacts, noise and / or changes in contrast). Score of 1, nondiagnostic. Contrast ratios (CRs) were calculated between reference tissues and vertebrae for single and parallel transmission.

A mean speed-up of 36% was achieved with dual source RF excitation. The total scan duration of a three-station whole spine examination including axial imaging stacks in all three stations could be reduced by 31 % (30:16 min. vs. 44:00 min.) using parallel RF transmission, as compared to single transmit mode. Spinal 3T MRI with parallel transmission yielded a median assessment of at least adequate image quality in all of the compared sequences. There was no case with a nondiagnostic image quality. The observed contrast changes were predominantly small (< 0.10 in 15 out of 24 CRs), though of statistical significance.

While shortening examination times by approximately one-third, dual-source RF transmission in 3T MRI of the spinal cord exhibits a diagnostic image quality readily comparable to that of standard single transmission sequences.

Parallel RF transmission yields an effective gain of time in 3T spine examinations.

Nelles, M, König, R, Gieseke, J, Urbach, H, Schild, H, Willinek, W, Dual Source RF Transmission for Clinical MR Imaging of the Spinal Cord at 3.0 Tesla.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9004098.html