Abstract
This paper describes the development and optimization of an innovative technique using an external surface coil to obtain high resolution, thin section MR images of the oesophagus using volunteers. T2 weighted fast spin echo sequences were performed with and without cardiac gating. The field of view (FOV), matrix size, slice thickness, number of signal averages (NSA), and repetition time (TR)/echo time (TE) were altered to optimize signal to noise ratio (SNR) whilst maintaining spatial resolution. The effect of cardiac gating was also investigated. Workstation images were evaluated on the ability to visualize: individual oesophageal wall layers; perioesophageal fat; the azygos vein and wall of the descending aorta, giving qualitative assessment of image clarity. The optimum sequence enabled the layers of the oesophageal wall and perioesophageal tissues to be demonstrated in an acceptable scan time of 7.07 min. A FOV of less than 250 mm degraded image quality so that individual oesophageal wall layers could not be depicted and noise within the image impaired visualization of posterior mediastinal structures. The results indicate that high resolution imaging of the oesophagus using an external surface coil can depict anatomic structures clearly and that the use of cardiac gating improves image clarity. The technique offers an alternative, non-invasive method of detailed imaging of the oesophagus.
References
1 Wakelin SJ, Deans C, Crofts TJ, Allan PL, Plevris JN, Paterson-Brown S. A comparison of computerised tomography, laparoscopic ultrasound and endoscopic ultrasound in the preoperative staging of oesophago-gastric carcinoma. Eur J Radiol 2002;41:161–7.
2 Preston SR, Clark GW, Martin IG, Ling HM, Harris KM. Effect of endoscopic ultrasonography on the management of 100 consecutive patients with oesophageal and junctional carcinoma. Br J Surg 2003;90:1220–4.
3 Schlick T, Heintz A, Junginger T. The examiner's learning effect and its influence on the quality of endoscopic ultrasonography in carcinoma of the esophagus and gastric cardia. Surg Endosc 1999;13:894–8.
4 Quint LE, Glazer GM, Orringer MB. Esophageal imaging by MR and CT: study of normal anatomy and neoplasms. Radiology 1985;156:727–31.
5 Lehr L, Rupp N, Siewert JR. Assessment of resectability of esophageal cancer by computed tomography and magnetic resonance imaging. Surgery 1988;103:344–50.
6 Inui K, Nakazawa S, Yoshino J, Yamao K, Yamachika H, Wakabayashi T, et al. Endoscopic MRI: preliminary results of a new technique for visualization and staging of gastrointestinal tumors. Endoscopy 1995;27:480–5.
7 Kulling D, Feldman DR, Kay CL, Hoffman BJ, Reed CE, Young JW, et al. Local staging of esophageal cancer using endoscopic magnetic resonance imaging: prospective comparison with endoscopic ultrasound. Endoscopy 1998;30:745–9.
8 Dave UR, Williams AD, Wilson JA, Amin Z, Gilderdale DJ, Larkman DJ, et al. Esophageal cancer staging with endoscopic MR imaging: pilot study. Radiology 2004;230:281–6.
9 Yamada I, Izumi Y, Kawano T, Yoshino N, Tetsumura A, Ohashi K, et al. Superficial esophageal carcinoma: an in vitro study of high-resolution MR imaging at 1.5T. J Magn Reson Imaging 2001;13:225–31.
10 Yamada I, Murata Y, Izumi Y, Kawano T, Endo M, Kuroiwa T, et al. Staging of esophageal carcinoma in vitro with 4.7-T MR imaging. Radiology 1997;204:521–6.
11 Brown G, Daniels IR, Richardson C, Revell P, Peppercorn D, Bourne M. Techniques and trouble-shooting in high spatial resolution thin slice MRI for rectal cancer. Br J Radiol 2005;78:245–51.
12 Markland CG, Manhire A, Davies P, Beggs D, Morgan WE, Salama FD. The role of computed tomography in assessing the operability of oesophageal carcinoma. Eur J Cardiothorac Surg 1989;3:33–6.
13 Sariego J, Mosher S, Byrd M, Matsumoto T, Kerstein M. Prediction of outcome in “respectable” esophageal carcinoma. J Surg Oncol 1993;54:223–5.
14 Feldman DR, Kulling DP, Hawes RH, Kay CL, Muckenfuss VR, Cotton PB, et al. MR endoscopy: preliminary experience in human trials. Radiology 1997;202:868–70.
