Perfusion MR imaging with a superparamagnetic iron oxide using T2-weighted and susceptibility-sensitive echoplanar sequences: evaluation of tumor vascularity in hepatocellular carcinoma.
OBJECTIVE
The study purpose was to examine the usefulness of perfusion echoplanar MR imaging with a superparamagnetic iron oxide (SHU-555A) for evaluating the vascularity of hepatocellular carcinomas.


METHODS
Twenty-two patients with 32 hepatocellular carcinomas underwent perfusion imaging with bolus injection (0.7-1.1 ml) of SHU-555A. Echoplanar sequences included multishot spin-echo (17 patients) and single-shot gradient-echo (five patients) imaging. Image acquisition was repeated every 30 sec for 3 min with the multishot spin-echo sequence and every 2 sec for 100 sec with the single-shot gradient-echo sequence. Lesion signal intensity versus time curves were created for quantitative analysis.


RESULTS
Transient decreases in tumor signal intensity (28.8% with multishot spin-echo and 63.3% with the single-shot gradient-echo) were seen in the perfusion phase. These decreases in signal intensity were statistically significantly (p < .01) different for each histologic type of hepatocellular carcinoma (poorly differentiated, 43.3%; well differentiated, 18.4%; and moderately differentiated, 24.8%). After the perfusion phase, the tumor signal intensities rapidly recovered. The multishot spin-echo sequence could detect some signal changes even in lesions smaller than 1 cm.


CONCLUSIONS
Hepatocellular carcinoma vascularity can be evaluated with perfusion echoplanar imaging with SHU-555A. Because of its excellent temporal resolution, the single-shot gradient-echo echoplanar sequence detects the transient signal decrease in most lesions. The high image quality of the multishot spin-echo echoplanar sequence allows evaluation of the vascularity of even very small lesions.
Ichikawa
T
T
Department of Radiology, Yamanashi Medical University, Tamaho, Nakakoma, Japan.
Arbab
A S
AS
Araki
T
T
Touyama
K
K
Haradome
H
H
Hachiya
J
J
Yamaguchi
M
M
Kumagai
H
H
Aoki
S
S
D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000098:blood supply* / Q000175:diagnosis; D003287:Contrast Media; D003911:Dextrans; D017352:Echo-Planar Imaging; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron; D008113:Liver Neoplasms / Q000098:blood supply* / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide