Detection of malignant hepatic tumors with ferumoxides-enhanced MRI: comparison of five gradient-recalled echo sequences with different TEs.
OBJECTIVE
The purpose of our study was to compare the detectability of malignant hepatic tumors on ferumoxides-enhanced MRI using five gradient-recalled echo sequences at different TEs.


METHODS
Ferumoxides-enhanced MRIs obtained in 31 patients with 50 malignant hepatic tumors (33 hepatocellular carcinomas, 17 metastases) were reviewed retrospectively by three independent offsite radiologists. T1-weighted gradient-recalled echo images with TEs of 1.4 and 4.2 msec; T2*-weighted gradient-recalled echo images with TEs of 6, 8, and 10 msec; and T2-weighted fast spin-echo images of livers were randomly reviewed on a segment-by-segment basis. Observer performance was tested using the McNemar test and receiver operating characteristic analysis for the clustered data. Lesion-to-liver contrast-to-noise ratio was also assessed.


RESULTS
Mean lesion-to-liver contrast-to-noise ratios were negative and lower with gradient-recalled echo at 1.4 msec than with the other sequences. Sensitivity was higher (p < 0.05) with gradient-recalled echo at 6, 8, and 10 msec and fast spin-echo sequences (75-83%) than with gradient-recalled echo sequences at 1.4 and 4.2 msec (46-48%), and was higher (p < 0.05) with gradient-recalled echo sequence at 8 msec (83%) than with gradient-recalled echo at 6 msec and fast spin-echo sequences (75-78%). Specificity was comparably high with all sequences (95-98%). The area under the receiver operating characteristic curve (A(z)) was greater (p < 0.05) with gradient-recalled echo at 6, 8, and 10 msec and fast spin-echo sequences (A(z) = 0.91-0.93) than with gradient-recalled echo sequences at 1.4 and 4.2 msec (A(z) = 0.82-0.85).


CONCLUSIONS
In the detection of malignant hepatic tumors, gradient-recalled echo sequences at 8 msec showed the highest sensitivity and had an A(z) value and lesion-to-liver contrast-to-noise ratio comparable with values from gradient-recalled echo sequences at 6 and 10 msec and fast spin-echo sequences.
Matsuo
Masayuki
M
Department of Radiology, Gifu University School of Medicine, 40 Tsukasamachi, Gifu 500-8705, Japan.
Kanematsu
Masayuki
M
Itoh
Kyo
K
Murakami
Takamichi
T
Maetani
Yoji
Y
Kondo
Hiroshi
H
Goshima
Satoshi
S
Kako
Nobuo
N
Hoshi
Hiroaki
H
Konishi
Junji
J
Moriyama
Noriyuki
N
Nakamura
Hironobu
H
D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D003287:Contrast Media; D003911:Dextrans; D004067:Digestive System Neoplasms / Q000473:pathology*; D017352:Echo-Planar Imaging; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide