Magnetic resonance imaging (MRI) in obstetrics. II. Fetal anatomy
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Dear Sir, The paper by Powell et al. [Br J Obstet Cynaecol (1988) 95,3&46] sets out well the potential and limitations of conventional magnetic resonance imaging (MRI) in obstetrics with respect to fetal anatomy. We agree with the authors’ conclusion that the future mode of choice is likely to be based on the echo planar technique. This does, however, require specialist equipment and is not easily implemented on the current generation of MR equipment. We find there is greater potential and fewer limitations in the use of the fast-scan (or gradient echo) technique. We use a General Electric 1.5 T Signa System within the guidelines laid down by the National Radiological Protection Board (1983). By using short TR (repetition time) a single image can be obtained in 3-Y s . This allows a series of images in one axis to be obtained in 3C90 s, and images in all three axes in approximately 1.5-4.5 min. Sukequent diagnostic images from a specific region can then be obtained in a further 5 min.
[1] Magnetic resonance imaging (MRI) in obstetrics. II. Fetal anatomy , 1988 .
[2] Revised guidance on acceptable limits of exposure during nuclear magnetic resonance clinical imaging. , 1983, The British journal of radiology.