MR imaging of the wrist in rheumatoid arthritis: comparison between 3T and 7T Poster No.:

C-2135

Congress:

ECR 2013

Type:

Scientific Exhibit

Authors:

A. Komorowski, F. Kainberger, S. Trattnig; Vienna/AT

Keywords:

Musculoskeletal joint, Musculoskeletal bone, MR, Comparative studies

DOI:

10.1594/ecr2013/C-2135

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. www.myESR.org

Page 1 of 11

Purpose Rheumatoid arthritis (RA) is characterized by synovial thickening, bone marrow edema and destruction of bones, cartilage and ligaments [1]. MR assessment of RA in the hand and wrist includes the detection and quantification of synovitis, bone erosions and bone marrow edema [2-4]. Further, changes in ligaments and cartilage may be visible if they are affected by the inflammatory process [5]. MR units with higher magnetic field strengths can increase signal-to-noise ratio (SNR), which may translate into shorter examination times or a higher spatial resolution of tiny anatomical structures [6-8]. However, technical difficulties have to be managed, including changes in relaxation times, magnetic field inhomogeneities and increased chemical shift or motion artifacts [9, 10]. A high SNR, contrast-to-noise ratio (CNR) and a distinct delineation of cortical and cancellous bone, peripheral nerves or articular cartilage is productive for an exact evaluation of the hand and wrist. The purpose of this study was to compare image parameters of the wrist relevant for RA with ultra-high-field and high-field MRI, including an analysis of SNR, CNR and quality of the imaged anatomical structures with optimized MR sequences.

Methods and Materials This study focused on 10 healthy volunteers (mean age: 24.2) and 2 patients (age: 32, 70) with RA according to the 2010 ACR/EULAR criteria, diagnosed by experienced rheumatologists. No healthy volunteers reported about pain or trauma of their hands and wrists or had previously undergone treatment for RA. In the volunteers, the measured wrists were assigned randomly; in the patients, the clinically dominant wrist was chosen (left/right hands: 6/6). The study was approved by the local ethics committee and informed consent was obtained from all participants. MR images were acquired with dedicated extremity coils and the individuals in the prone position, both at 7T and at 3T. The field-of-view included the wrist and the 1st to 5th metacarpophalangeal joints. Five different sequences with approximately the same acquisition time at 7T and 3T and noise distribution images with a zero-voltage pulse were obtained for both field strengths. The sequences were as follows: • • •

coronal T1 spin echo (T1 SE) coronal T1 fast imaging with steady precession (T1 FISP) coronal PD turbo-spin echo with fat saturation (PD TSE)

Page 2 of 11

• •

3D FLASH with water excitation (3D FLASH) 3D dual-echo steady state (3D DESS)

The quantitative evaluation focused on the healthy volunteers. The standard deviation of noise was determined by measuring a total number of 16 ROIs within each noise distribution image (an exception was the T1 FLASH sequence, where it was calculated by measuring the ROIs in the free area next to the wrist). SNR measurements were performed in four different regions on coronal images by calculating the ratio of mean signal intensity and standard deviation of noise within a defined region-of-interest (ROI): muscle, cartilage, bone marrow and cortical bone. CNR was calculated as the difference of the following SNR values: 1. 2. 3.

cortical bone/bone marrow cortical bone/cartilage cartilage/muscle.

The qualitative evaluation was performed on a 5-point scale (0: not definable; 4: excellent) of the images from the healthy volunteers and the patients. Delineation of the following anatomical structures was rated: Triangular fibrocartilage complex (TFCC), scapholunate (SL) ligament, intercarpal cartilage, median nerve, ulnar nerve, as well as cortical and cancellous bone.

Results All images showed an increase in spatial resolution with ultra-high-field MRI: • •

The T1 FISP sequence showed the highest in-plane resolution (0.26 x 0.26 mm²; slice thickness: 1.5 mm; 7T). The T1 FLASH sequence showed the highest isotropic resolution (0.40 x 0.40 x 0.40 mm³; 7T).

SNR increased significantly for three sequences at 7T, compared to 3T: • • •

T1 FISP (3T: Fig. 1 on page 4, 7T: Fig. 2 on page 5) PD TSE (3T: Fig. 3 on page 6, 7T: Fig. 4 on page 7) 3D DESS (3T: Fig. 5 on page 8, 7T: Fig. 6 on page 9).

Page 3 of 11

A maximum increase was achieved with the T1 FISP sequence for cartilage imaging (3.8fold increase; 3T: 163.2±24.2, 7T: 618.6±125.6). Two sequences showed various changes: with the T1 FLASH sequence SNR significantly increased for cartilage (1.3-fold) and simultaneously decreased for cortical bone (0.7time decrease) and bone marrow (0.5-time decrease). The T1 SE sequence showed a decrease of SNR at 7T, except for bone marrow (1.6-fold increase).

CNR changes varied for each anatomical structure and MR-sequence. The sequences, which showed a significant increase in SNR at 7T also increased CNRs significantly: T1 FISP, PD TSE & 3D DESS. The T1 FISP sequence showed, as well as for SNR, the maximal increase: 4.6-fold increase in CNR (1. cortical bone/cartilage; 3T: 124.4±26.1, 7T: 569.3±127.6).

The qualitative evaluation showed an increase in image quality for three sequences at 7T: T1 FISP, PD TSE & 3D DESS. Regarding the visibility of anatomical structures of the hand and wrist, a significant improvement on the 5-point scale was observed with ultra-high-field MRI for the delineation of: • • •

TFCC & SL-ligament (PD TSE; 3T: 2.08±0.9, 7T: 3.23±0.6) cartilage (PD TSE; 3T: 2.23±0.7, 7T: 3.38±0.7) cortical and cancellous bone (T1 FISP; 3T: 2.75±0.5, 7T: 3.25±0.9).

Images for this section:

Page 4 of 11

Fig. 1: MRI of the wrist: cor. T1 FISP sequence, 3T

Page 5 of 11

Fig. 2: MRI of the wrist: cor. T1 FISP sequence, 7T

Page 6 of 11

Fig. 3: MRI of the wrist: cor. PD TSE sequence, 3T

Page 7 of 11

Fig. 4: MRI of the wrist: cor. PD TSE sequence, 7T

Page 8 of 11

Fig. 5: MRI of the wrist: ax. 3D DESS sequence, 3T

Fig. 6: MRI of the wrist: ax. 3D DESS sequence, 7T

Page 9 of 11

Conclusion A higher SNR and CNR, increased spatial resolution, as well as an improved image quality may be useful for the evaluation of the hand and wrist, especially for pathologies commonly found in RA. Further optimization of sequence parameters, MRI protocols and particularly dedicated wrist-coils are necessary to reach the full potential of ultra-highfield MRI. This study exemplifies the possibilities to improve image quality with higher field strengths.

References 1. E. Jimenez-Boj, I. Nobauer-Huhmann, B. Hanslik-Schnabel, R. Dorotka, A.H. Wanivenhaus, F. Kainberger, et al., Bone erosions and bone marrow edema as defined by magnetic resonance imaging reflect true bone marrow inflammation in rheumatoid arthritis, Arthritis Rheum 56(2007), pp. 1118-1124. 2. Weber U, Østergaard M, Lambert RG, Maksymowych WP. The impact of MRI on the clinical management of inflammatory arthritides. Skeletal Radiol. 2011 Sep;40(9):1153-73. Epub 2011 Aug 17 3. P. Conaghan, M. Lassere, M. Ostergaard, C. Peterfy, F. McQueen, P. O'Connor, et al., OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 4: an international multicenter longitudinal study using the RA-MRI Score, J Rheumatol 30(2003), pp. 1376-1379. 4. F. McQueen, M. Lassere, J. Edmonds, P. Conaghan, C. Peterfy, P. Bird, et al., OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Summary of OMERACT 6 MR Imaging Module, J Rheumatol 30(2003), pp. 1387-1392. 5. Haavardsholm EA, Østergaard M, Ejbjerg BJ, Kvan NP, Kvien TK, et al. Introduction of a novel magnetic resonance imaging tenosynovitis score for rheumatoid arthritis: reliability in a multireader longitudinal study. Annals of the Rheumatic Diseases 2007;66(9):1216-20. 6. C.G. Peterfy, MRI of the wrist in early rheumatoid arthritis, Ann Rheum Dis 63(2004), pp. 473-477.

Page 10 of 11

7. F.M. McQueen, The use of MRI in early RA, Rheumatology (Oxford) 47(2008), pp. 1597-1599. 8. C.J. Ashman, S. Farooki, A.M. Abduljalil and D.W. Chakeres, In vivo high resolution coronal MRI of the wrist at 8.0 tesla, J Comput Assist Tomogr 26(2002), pp. 387-391. 9. R.R. Regatte and M.E. Schweitzer, Ultra-high-field MRI of the musculoskeletal system at 7.0T, J Magn Reson Imaging 25(2007), pp. 262-269. 10. Chang G, Friedrich KM, Wang L, Vieira RL, Schweitzer ME, Recht MP, Wiggins GC, Regatte RR. MRI of the wrist at 7 tesla using an eight-channel array coil combined with parallel imaging: preliminary results. J Magn Reson Imaging. 2010 Mar;31(3):740-6.

Personal Information Arkadiusz Komorowski Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University of Vienna, Vienna, Austria E-mail: [email protected] Franz Kainberger Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University of Vienna, Vienna, Austria Siegfried Trattnig Department of Radiology, MR Centre of Excellence, Medical University of Vienna, Vienna, Austria

Page 11 of 11