Fast MR imaging of abdomen: application of the QD body coil and low refocusing flip angle.
The fast spin-echo (FSE) method as applied to abdominal imaging has undergone considerable technical and clinical study over the past several years. However, except in a limited number of institutions, this time-saving sequence has not replaced the conventional spin-echo (CSE) method. In particular, FSE is less frequently employed for examination of the liver because FSE and CSE images of hepatic tumors and normal hepatic tissues differ significantly in terms of contrast. The signal reduction effect of magnetization transfer contrast (MTC) is affected by the number of slice sections and by the specific absorption rate (SAR). We have employed a newly developed quadrature detection (QD) body coil to enhance the signal-to-noise ratio (S/N) and a low refocusing flip angle to suppress SAR and MTC effects. We have also evaluated the effectiveness of this new method by carrying out visual assessment of clinical images and quantitative measurements of signal intensity in these images. Several problems must be overcome before the FSE method is able to replace the CSE method in the clinical examination of the abdomen. The selection of sequences with a low refocusing flip angle combined with the use of the QD body coil promises to be one possible solution to these problems.
Nitatori
T
T
Department of Radiology, Kyorin University, School of Medicine, Tokyo, Japan.
Seki
T
T
Hachiya
J
J
Kassai
Y
Y
D000005:Abdomen / Q000473:pathology*; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis; D004867:Equipment Design; D006392:Hemangioma, Cavernous / Q000175:diagnosis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*