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1 DOI: /jkma pissn: eissn: Focused Issue of This Month High field strength magnetic resonance imaging of abdominal diseases Sung Eun Rha, MD* Department of Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea * Corresponding author: Sung Eun Rha, serha@catholic.ac.kr Received November 1, 2010 Accepted November 14, 2010 Abstract Due to the development of dedicated receiver coils for 3 tesla (T) magnetic resonance (MR) imaging and increased gradient performance, 3T MR imaging of the abdomen is rapidly becoming a part of routine clinical practice. The most important advantage of 3T MR imaging is a higher signal-to-noise ratio and contrast-to-noise ratio compared with 1.5T systems, which can be used to improve spatial resolution and shorten image acquisition time. In the abdomen, the improved image quality of non-enhanced and enhanced solid organ imaging, MR angiography, MR cholangiopancreatography, and MR spectroscopy can be obtained at 3T due to the increased signal-to-noise ratio and contrast-to-noise ratio. However, 3T abdominal MR imaging also presents several technical challenges, such as increased energy deposition within the patient's body, standing wave artifacts, and increased susceptibility artifacts. Therefore, abdominal MR imaging at 3T requires adjustments in the sequence parameters of pulse sequences designed for 1.5T to optimize image quality. At present, 3T abdominal MR imaging is feasible with high image quality in an acceptable scan time, but 3T imaging is not significantly superior to 1.5T imaging in terms of cost-effectiveness. Future improvements in coil technology and new sequences suitable for 3T may enable wider clinical use of 3T for abdominal MR imaging. Keywords: Magnetic resonance imaging; High field strength; Abdominal diseases; 3 tesla c Korean Medical Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 1065

5T were 5,500/88 (repetition time msec/echo time msec), 6-mm section thickness, 320x224 matrix, and 36- cm field of view.

2 Rha SE A B Figure 1. Comparison of T2-weighted fast spin echo images obtained with 1.5 tesla (T) (A) and 3T (B) systems in the same patient. The image obtained at 3T shows an increased signal-to-noise ratio with increased conspicuity of a small hepatic cyst (arrow). Parameters at 1.5T were 5,500/88 (repetition time msec/echo time msec), 6-mm section thickness, 320x224 matrix, and 36- cm field of view. Parameters at 3T were 2,500/99, 6-mm section thickness, 512x255 matrix, and 36-cm field of view. Figure 2. High-resolution isotropic 3D T2-weighted images of the female pelvis at 3 tesla (T). (A) 3D turbo spin echo T2-weighted image in a 58-year-old woman with cervical cancer shows slightly hyperintense endocervical mass (arrow). Sequence parameters were sampling perfection with application of optimized contrasts using different flip angle evolution (SPACE), 2,000/127, 1-mm section thickness, echo train of 89, 256x256 matrix, and 18-cm field of view. (B) Sagittal reconstructed image from 3D data set again shows hyperintense endocervical mass (arrow) and two nabothian cysts (arrowheads). B, bladder; R, rectum. A B 1066

3 High field strength magnetic resonance imaging of abdominal diseases A B C Figure 3. Increased conspicuity of hepatic metastasis at 3 tesla (T) magnetic resonance imaging using liver-specific contrast agent in a pa-tient with rectal cancer. (A) Contrast-enhanced computed tomography shows a subtle low density lesion (arrow) at the periphery of the right hepatic lobe. (B) Axial dynamic contrast-enhanced 3D gradient echo T1-weighted image with fat saturation after injection of gadoxetic acid shows a small low signal intensity lesion with peripheral rim enhancement on hepatic arterial phase. (C) On hepatobiliary phase obtained 20 minutes after contrast injection, the mass shows distinct low signal intensity (arrow) compared with background liver enhancement. Another unexpected small metastatic lesion (arrowhead) is also easily detected the segment 7 of the liver. 1067

transplantation demonstrates excellent contrast-to-noise ratio and detailed vascular anatomy. Figure 5.

4 Rha SE Figure 4. Maximum-intensity projection image from 3 tesla abdominal magnetic resonance angiographic data obtained from a 52-year-old woman with kidney transplantation demonstrates excellent contrast-to-noise ratio and detailed vascular anatomy. Figure 5. Coronal maximum-intensity projection image from 3D magnetic resonance cholangiopancreatography at 3 tesla shows increased fluid conspicuity due to a high signal-to-noise ratio in a 42-year-old man with pancreas head adenocarcinoma. Abrupt cut-off of the distal common bile duct and pancreatic duct at the head portion (arrow) is well demonstrated. 1068

High field strength magnetic resonance imaging of abdominal diseases A B Figure 6. Increased susceptibility artifacts at 3 tesla in a 64-year-old man with proximal rectal cancer.

5 High field strength magnetic resonance imaging of abdominal diseases A B Figure 6. Increased susceptibility artifacts at 3 tesla in a 64-year-old man with proximal rectal cancer. Pelvic magnetic resonance images were obtained after endoscopic biopsy and metallic clipping. Sagittal T2-weighted image (A) and diffusion-weighted image (B) (b=500 sec/mm2) show prominent susceptibility artifacts around the metallic clip (arrows). It is difficult to know the exact extent of the rectal cancer due to the severe artifacts. 1069

6 Rha SE Figure 7. Standing wave artifact at 3 tesla in a 35-year-old woman with a huge pelvic mass. Sagittal T2-weighted fast spin echo magnetic resonance image of the pelvis shows a band-like loss of signal intensity (arrows) due to magnetic inhomogeneity. 1070

7 High field strength magnetic resonance imaging of abdominal diseases REFERENCES 11. Merkle EM, Dale BM, Paulson EK. Abdominal MR imaging at 3T. Magn Reson Imaging Clin N Am 2006; 14: Barth MM, Smith MP, Pedrosa I, Lenkinski RE, Rofsky NM. Body MR imaging at 3.0 T: understanding the opportunities and challenges. Radiographics 2007; 27: Chang KJ, Kamel IR, Macura KJ, Bluemke DA. 3.0-T MR imaging of the abdomen: comparison with 1.5 T. Radiographics 2008; 28: Merkle EM, Dale BM. Abdominal MRI at 3.0 T: the basics revisited. AJR Am J Roentgenol 2006; 186: Katz-Brull R, Rofsky NM, Lenkinski RE. Breathhold abdominal and thoracic proton MR spectroscopy at 3T. Magn Reson Med 2003; 50: Soher BJ, Dale BM, Merkle EM. A review of MR physics: 3T versus 1.5T. Magn Reson Imaging Clin N Am 2007; 15: Akisik FM, Sandrasegaran K, Aisen AM, Lin C, Lall C. Abdominal MR imaging at 3.0 T. Radiographics 2007; 27: Erturk SM, Alberich-Bayarri A, Herrmann KA, Marti-Bonmati L, Ros PR. Use of 3.0-T MR imaging for evaluation of the abdomen. Radiographics 2009; 29: Hussain SM, Wielopolski PA, Martin DR. Abdominal magnetic resonance imaging at 3.0 T: problem or a promise for the future? Top Magn Reson Imaging 2005; 16: Martin DR, Friel HT, Danrad R, De Becker J, Hussain SM. Approach to abdominal imaging at 1.5 Tesla and optimization at 3 Tesla. Magn Reson Imaging Clin N Am 2005; 13: Krautmacher C, Willinek WA, Tschampa HJ, Born M, Träber F, Gieseke J, Textor HJ, Schild HH, Kuhl CK. Brain tumors: fulland half-dose contrast-enhanced MR imaging at 3.0 T compared with 1.5 T. Initial Experience. Radiology 2005; 237: Tsurusaki M, Semelka RC, Zapparoli M, Elias J Jr, Altun E, Pamuklar E, Sugimura K. Quantitative and qualitative comparison of 3.0T and 1.5T MR imaging of the liver in patients with diffuse parenchymal liver disease. Eur J Radiol 2009; 72: Ramalho M, Altun E, Heredia V, Zapparoli M, Semelka R. Liver MR imaging: 1.5T versus 3T. Magn Reson Imaging Clin N Am 2007; 15: Campeau NG, Huston J 3rd, Bernstein MA, Lin C, Gibbs GF. Magnetic resonance angiography at 3.0 Tesla: initial clinical experience. Top Magn Reson Imaging 2001; 12: Rohrer M, Bauer H, Mintorovitch J, Requardt M, Weinmann HJ. Comparison of magnetic properties of MRI contrast media solutions at different magnetic field strengths. Invest Radiol 2005; 40: Michaely HJ, Nael K, Schoenberg SO, Finn JP, Laub G, Reiser 1071

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9 High field strength magnetic resonance imaging of abdominal diseases Peer Reviewers Commentary 1073

1093_특집- 구현우

1093_특집- 구현우 J Korean Med ssoc 2010 December; 53(12): 1093-1102 DOI: 10.5124/jkma.2010.53.12.1093 pissn: 1975-8456 eissn: 2093-5951 http://jkma.org Focused Issue of This Month High field strength magnetic resonance