MR imaging of the liver: comparison between single-shot echo-planar and half-Fourier rapid acquisition with relaxation enhancement sequences.
OBJECTIVE
To evaluate single-shot T2-weighted magnetic resonance sequences and their role in clinical practice in patients with hepatic lesions.


METHODS
Prospective comparison of echo-planar and half-Fourier rapid acquisition with relaxation enhancement (RARE) imaging was performed in 80 patients with focal hepatic lesions. Spin-echo (SE) single-shot echo-planar (echo times, 47 and 80 msec) and half-Fourier RARE (echo time, 59 msec) images were compared with turbo SE (repetition time msec/echo time msec = 3,200-7,600/90) images. Quantitative, qualitative, and receiver operating characteristic (ROC) analyses were performed.


RESULTS
For liver, signal-to-noise ratios on half-Fourier RARE images were significantly higher than those on echo-planar images (P < .01). For cystic lesions, contrast on half-Fourier RARE and echo-planar images was slightly higher than that on turbo SE images. For solid lesions, contrast on echo-planar images was better than that on half-Fourier RARE or turbo SE images. Artifacts including ghosting, bowel motion, susceptibility difference, and chemical shift were negligible on half-Fourier RARE images in all patients, whereas susceptibility difference and chemical shift of various degrees were seen on all echo-planar images. On the basis of ROC analyses, tumor detection rates were significantly higher with half-Fourier RARE and turbo SE images than with echo-planar images (P < .01).


CONCLUSIONS
Echo-planar images provide sufficient contrast to allow detection of both solid and cystic masses, but severe artifacts preclude routine use. Half-Fourier RARE images are free from artifacts (chemical shift and susceptibility) and diagnostic performance with them is similar to that with turbo SE images.
Yamashita
Y
Y
Department of Radiology, Kumamoto University School of Medicine, Japan.
Tang
Y
Y
Namimoto
T
T
Mitsuzaki
K
K
Takahashi
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis; D018281:Cholangiocarcinoma / Q000175:diagnosis; D003560:Cysts / Q000175:diagnosis; D017352:Echo-Planar Imaging / Q000379:methods*; D005069:Evaluation Studies as Topic; D005260:Female; D005583:Fourier Analysis; D006391:Hemangioma / Q000175:diagnosis; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007422:Intestines / Q000473:pathology; D008099:Liver / Q000473:pathology; D008107:Liver Diseases / Q000175:diagnosis; D008113:Liver Neoplasms / Q000175:diagnosis*; D008223:Lymphoma / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity