Comparison of Image quality in temporal bone MRI at 3T using 2D selective RF excitation versus a routine SPACE sequence

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1 Comparison of Image quality in temporal bone MRI at 3T using 2D selective RF excitation versus a routine SPACE sequence Poster No.: C-1065 Congress: ECR 2015 Type: Authors: Keywords: DOI: Scientific Exhibit M. Schulze, A. Seeger, K. Reimann, U. Ernemann, T.-K. Hauser; Tübingen/DE Imaging sequences, MR, Head and neck, Cancer /ecr2015/C-1065 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 6

2 Aims and objectives Normal 0 false false false EN-US X-NONE X-NONE 2D selective radiofrequency excitation (2DRF) (ZOOMit, SIEMENS, Erlangen, Germany) offers the possibility to optimize fast spin echo imaging like SPACE. Using this technique it is possible to reduce the field of view along the phase encoding dimension (i.e. zooming in), leading to shorter acquisition times. The aim of our study was to compare the clinical benefit of 2D RF excitation in the case of either reducing image acquisition time (ZOOMit-time) or increasing of spatial resolution (ZOOMit-resolution) without increasing acquisition time at a 3.0 T MRI. Methods and materials 32 patients (mean age: 48 years, (19-78 years)) were examined at 3 T system with (1) routine-space (time: 4min 20s), (2) ZOOMit-time (time: 2min 33s) und (3) ZOOMit-resolution (time: 4min 22s). sequence protocol: TR: 1000ms / TE: 136ms, FOV: 200mm (1 and 2) resp. 180 (3) and isotropic voxel size: 0,52 (1 and 2) resp. 0,2x0,2x0,4 (3). Quantative and qualitative image quality was assessed. Results Page 2 of 6

3 Normal 0 false false false EN-US X-NONE X-NONE Evaluating the cochlear structures: ZOOMit-time showed no significant difference in image quality depicting basal and second turn of the cochlea and lamina spiralis compared to the routine-space sequence. Apical turn of the cochlea and the Modiolus were significantly (p<0.05) better delineated in ZOOMit-time compared to routine-space. ZOOMit-resolution yielded significantly better delineation of all cochlear structures (Fig.1). The vestibular structures (vestibulum, anterior, posterior and lateral semicircular duct) could be delineated in equal quality in ZOOMit-time and routine-space respectively with exception of the anterior semicircular duct which showed a significant better delineation (p<0.05) on routine-space. However all vestibular structures showed better delineation on ZOOMit-resolution than the other two sequences. Evaluating the cranial nerves within the inner auditory canal (IAC): The entry of the cochlear nerve into the Modiolus as well as the course within the IAC could best be depicted in ZOOMit-resolution (p<0.05) (Fig.2). The same results were detected for the facial nerve and the vestibular nerve before its division into a superior and inferior part. The superior and inferior part of the vestibular nerve could be best depicted using ZOOMit-resolution (Fig.3). Images for this section: Page 3 of 6

4 Fig. 1: Axial ZOOMit-resolution. Note the sharp edge definition of the spiral lamina and modiolus. Fig. 2: Parasaggital reformation of IAC, routine-space sequence. Page 4 of 6

5 Fig. 3: Parasaggital reformation of IAC, ZOOMit-resolution sequence. Note sharp edge definition and clear differentiaion of the nerves within the IAC. Page 5 of 6

6 Conclusion Normal 0 false false false EN-US X-NONE X-NONE Resolution optimized ZOOMit-resolution sequence offers best delimitation of anatomic structures in temporal bone compared to all tested sequences. Image quality of time optimized ZOOMit-time is equivalent to routine -SPACE. Personal information References Normal 0 false false false EN-US X-NONE X-NONE Finsterbusch J. Fast-spin-echo imaging of inner fields-of-view with 2D-selective RF excitations. J Magn Reson Imaging Jun;31(6): Rieseberg S et al. Two-dimensional spatially-selective RF excitation pulses in echoplanar imaging. Magn Reson Med Jun;47(6): Page 6 of 6