Black-blood diffusion-weighted EPI acquisition of the liver with parallel imaging: comparison with a standard T2-weighted sequence for detection of focal liver lesions.
OBJECTIVE
To evaluate the performance of black-blood diffusion-weighted (DW)-EPI sequences with parallel imaging for the detection of focal liver lesions in comparison with a standard T2-weighted (T2-w) sequence.


METHODS
Twenty patients with known or suspected focal liver lesions underwent liver MRI using a DW-EPI sequence with a b-value of 50 S/mm2 (TR/TE 2200/50 ms) and a standard fat-saturated T2-w sequence (TR/TE 2800/107 ms) with 6-mm slice thickness on a 1.5-T MRI system. Both sequences used parallel imaging with an acceleration factor of 2. Overall image quality and degree of artifacts were compared on a 5-point scale with 5 being the most desirable score. The detection rate and the level of confidence with regard to lesion detection were evaluated for both sequences in comparison to a contrast-enhanced (Gadolinium and SPIO) MR examination, which was used as the standard of reference.


RESULTS
The DW-EPI sequence showed significantly (P < 0.05) improved overall image quality (average score 4.15 vs. 3.63) and fewer artifacts (average score 4.2 vs. 3.5) in comparison with the T2-w sequence. The sensitivity for lesion detection was superior in the DW-EPI sequence (83% vs. 61%). The level of confidence in the detection of focal liver lesions was also superior for the DW-EPI sequence in comparison with the T2-w sequence (average score 3.9 vs. 3.2).


CONCLUSIONS
DW-EPI sequences for liver-imaging are feasible with parallel imaging and show excellent image quality. They may contribute to more easy and confident lesion detection in comparison with T2-w sequences.
Zech
Christoph J
CJ
Institute of Clinical Radiology, University Hospital Munich-Grosshadern, Ludwigs-Maximilians University, Munich, Germany. christoph.zech@med.uni-muenchen.de
Herrmann
Karin A
KA
Dietrich
Olaf
O
Horger
Wilhelm
W
Reiser
Maximilian F
MF
Schoenberg
Stefan O
SO
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003911:Dextrans; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D052203:Ferrosoferric Oxide; D019786:Gadolinium DTPA; D006801:Humans; D007501:Iron; D008107:Liver Diseases / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D019786:Gadolinium DTPA; D052203:Ferrosoferric Oxide