Diffusion Weighted Imaging in Musculoskeletal MRI: Analysis on Optimal Number of Excitations Providing better Differentiation of Maglignant Tumor

악성종양의 감별진단을 위한 근골격의 확산강조영상 검사 시 최적의 여기횟수

  • Received : 2018.07.23
  • Accepted : 2018.08.09
  • Published : 2018.08.28


The purpose of this study was to determine the optimal number of excitations(NEX) of diffusion weighted imaging(DWI) which is clinically useful in patients with musculoskeletal diseases while the scan time is relatively long. In this study, 30 patients underwent knee MRI using diffusion weighted image sequence using b values targeted on the bone and muscle. The NEX were varied from 1 to 5 and the ADC values were measured and analyzed. As a result of the study, 4 NEX and 2 NEX showed an statistically identical effect with the existing NEX on the bone and muscle diffusion weighted images, respectively. Also, it proved that the scan time could be significantly reduced by 21.2 % and 59.6 % compared to the established NEX which meant the optimal NEX could replace the existing NEX. In conclusion, applying the optimal NEX on the musculoskeletal bone and soft tissue DWI could improve the problems caused by the long scan time.


ADC Value;Number of Excitations;Diffusion-Weighted Imaging;Scan Time;Musculoskeletal


  1. N. Bharwani and D. M. Koh, "Diffusionweighted imaging of the liver: an update," Cancer imaging, Vol.13, No.2, p.171, 2013.
  2. N. H. Koo, H. B. Lee, K. W. Choi, S. Y. Son, and B. G. Yoo, "The Study on Signal to Noise Ratio of Single-Shot Turbo Spin Echo to Reduce Image Distortion in Brain Stem Diffusion MRI," Journal of the Korean Society of Radiology, Vol.10, No.4, pp.241-246, 2016.
  3. J. H. Koo, Y. C. Yoon, and J. H. Kim, "Diffusion-weighted and Dynamic Contrastenhanced MRI of Metastatic Bone Tumors: Correlation of the Apparent Diffusion Coefficient, Ktrans and ve values," Journal of the Korean Society of Magnetic Resonance in Medicine, Vol.18, No.1, pp.25-33, 2014.
  4. D. W. Park, "Advances in magnetic resonance technique for tumor imaging," Journal of the Korean Medical Association, Vol.58, No.6, pp.516-522, 2015.
  5. T. W. Redpath, "Signal-to-noise ratio in MRI," The British Journal of Radiology, Vol.71, No.847, pp.704-707, 1998.
  6. K. W. Choi and S. Y. Son, "An effectiveness of multitransmit parallel technique on scan time reduction in hip joint MRI," Journal of the Korea Academia-Industrial cooperation Society, Vol.17, No.3, pp.103-108, 2016.
  7. S. Y. Son, K. W. Choi, K. J. Park, J. S. Lee, and B. G. Yoo, "A effectiveness of multi-transmit parallel technique on magnetic resonance imaging of FOV less than 26 cm," Journal of Radiological Science and Technology, Vol.38, No.4, pp.429-435, 2015.
  8. S. R. Na, K. W. Choi, N. H. Koo, B. G. Yoo, and S. Y. Son, "A Change of Apparent Diffusion Coefficient in Diffusion Weighted Imaging Applied with Rectangular FOV Technique," Journal of the Korean Society of Radiology, Vol.10, No.7, pp.545-550, 2016.
  9. E. M. Escobedo, J. C. Hunter, G. C. Zink-Brody, A. J. Wilson, S. D. Harrison, and D. J. Fisher, "Usefulness of turbo spin-echo MR imaging in the evaluation of meniscal tears: comparison with a conventional spin-echo sequence," American journal of roentgenology, Vol.167, No.5, pp.1223-1227, 1996.
  10. H. K. Song, A. C. Wright, R. L. Wolf, and F. W. Wehrli, "Multislice double inversion pulse sequence for efficient black‐blood MRI," Magnetic Resonance in Medicine, Vol.47, No.3, pp.616-620, 2002.
  11. X. Golay, J. Gillen, P. C. Van Zijl, and P. B. Barker, "Scan time reduction in proton magnetic resonance spectroscopic imaging of the human brainm" Magnetic Resonance in Medicine, Vol.47, No.2, pp.384-387, 2002.
  12. J. S. Bauer, S. Banerjee, T. D. Henning, R. Krug, S. Majumdar, and T. M. Link, "Fast high-spatial-resolution MRI of the ankle with parallel imaging using GRAPPA at 3 T," American Journal of Roentgenology, Vol.189, No.1, pp.240-245, 2007.
  13. K. P. Pruessmann, M. Weiger, M. B. Scheidegger, and P. Boesiger, "SENSE: sensitivity encoding for fast MRI," Magnetic resonance in medicine, Vol.42, No.5, pp.952-962, 1999.<952::AID-MRM16>3.0.CO;2-S
  14. H. Rahbar, S. C. Partridge, W. B. DeMartini, R. L. Gutierrez, S. Parsian, and C. D. Lehman, "Improved B1 homogeneity of 3 tesla breast MRI using dual‐source parallel radiofrequency excitation," Journal of Magnetic Resonance Imaging, Vol.35, No.5, pp.1222-1226, 2012.
  15. K. W. Choi, H. B. Lee, S. R. Na, B. G. Yoo, and S. Y. Son, "The Study on Reduction of Image Distortion by using Single-Shot Turbo Spin Echo in Brain Stem Diffusion MRI," Journal of the Korean Society of Radiology, Vol.10, pp.279-284, 2016.