Gradient- and spin-echo T2-weighted imaging for SPIO-enhanced detection and characterization of focal liver lesions.
OBJECTIVE
To evaluate superparamagnetic iron oxide (SPIO)-enhanced breathhold T2-weighted GRASE imaging in detection and characterization of focal liver lesions.


METHODS
In 30 patients (including 20 with cirrhosis) with 39 malignant and 25 benign lesions, gradient- and spin-echo (GRASE) images with two echo times (75 and 90 msec; GRASE75 and GRASE90) were obtained prior to and following administration of SPIO, and compared with respiratory-triggered and breathhold fast spin-echo (RT-FSE and BH-FSE) images. Two readers evaluated image quality and reviewed 240 liver segments for sensitivity and specificity. Signal-to-noise ratio (SNR), and its reduction in liver and spleen after administration of SPIO, and lesion-to-liver contrast-to-noise ratio (CNR) were measured.


RESULTS
Compared with RT-FSE and BH-FSE, GRASE reduced scan time by 77% to 82% and 21% to 27%, respectively. The image qualities with BH-FSE and GRASE75 were higher than with BH-FSE and GRASE90. BH-FSE showed higher specificity than RT-FSE and GRASE90, but otherwise there were no significant differences between pulse sequences for sensitivity or specificity. The mean SNR and CNR of the lesions with RT-FSE were significantly higher than with the other methods. SPIO-induced signal reduction of liver SNR was smallest with BH-FSE.


CONCLUSIONS
GRASE is faster and more sensitive to SPIO than FSE, but its sensitivity and specificity were slightly inferior to those of BH-FSE. Image quality is a current limitation.
Department of Radiology, Division of Magnetic Resonance Imaging, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. yoshikawa0816@aol.com
Takeshi
T
Yoshikawa
Donald G
DG
Mitchell
Shozo
S
Hirota
Yoshiharu
Y
Ohno
Kazushige
K
Oda
Takaki
T
Maeda
Masahiko
M
Fujii
Kazuro
K
Sugimura
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis*; D015179:Colorectal Neoplasms / Q000473:pathology*; D003911:Dextrans; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D052203:Ferrosoferric Oxide; D006525:Hepatitis, Viral, Human / Q000150:complications; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007501:Iron; D008103:Liver Cirrhosis / Q000175:diagnosis; D008104:Liver Cirrhosis, Alcoholic / Q000175:diagnosis; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010087:Oxides; D012680:Sensitivity and Specificity; D013997:Time Factors
D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide