OBJECTIVE
.
The aim of this study was to compare the sensitivity of pulse inversion harmonic
digital sonography, unenhanced transabdominal sonography, and ferumoxides-enhanced
MR imaging in the depiction of liver metastases. In addition, pulse inversion
harmonic digital sonography was performed at different scanning times after Levovist injection
to define the best phase for depiction.
SUBJECTS AND METHODS.
Twenty-six consecutive patients with findings of extrahepatic
primary malignancies and liver metastases suspected on transabdominal sonography
were examined with both pulse inversion harmonic imaging and ferumoxides-enhanced MR
imaging within a 7-day period. Pulse inversion harmonic imaging was performed before and
at 20, 100, and 180 sec after a bolus injection of Levovist. MR imaging was performed before
and after ferumoxides administration, using breath-hold gradient-recalled echo T1-weighted
and turbo spin-echo short tau inversion recovery T2-weighted sequences. Two radiologists independently
evaluated image quality, and the number, location, and diameter of lesions
scanned using both techniques. Intraoperative sonography or at least 8-month follow-up confirmed
the lesions depicted. Analyses included Wilcoxon’s signed rank test and Interclass correlation
test.
RESULTS.
Levovist-enhanced pulse inversion harmonic imaging revealed 104 metastases
on the first scan after contrast injection, 126 on the second scan, and 118 on the third, compared
with 66 on the unenhanced scan. Pulse inversion harmonic digital sonography depicted
90% of lesions shown on ferumoxides-enhanced MR imaging (140 metastases) (
p
= 0.001).
CONCLUSION.
Levovist-enhanced pulse inversion harmonic digital sonography is a
sensitive technique for depiction of liver metastases. Pulse inversion harmonic digital sonography
may have a potential role in imaging patients with possible metastatic involvement of
the liver. Further studies are needed to define its place in the workup of these patients. At
present, ferumoxides-enhanced MR imaging, being more sensitive, must be performed in all
patients in whom pulse inversion harmonic digital sonography is not conclusive or when after
pulse inversion harmonic digital sonography, patients remain eligible for surgery.
