Mori K, Yoshioka H, Itai Y, Okamoto Y, Mori H, Takahashi N, Saida Y.Arterioportal shunts in cirrhotic patients: evaluation of the difference between tumorous and nontumorous arterioportal shunts on MR imaging with superparamagnetic iron oxide. AJR Am J Roentgenol 2000 Dec;175(6):1659-64
OBJECTIVE: The study objective
was to distinguish between the features of tumorous and nontumorous
arterioportal shunts on superparamagnetic iron oxide-enhanced
MR imaging in patients with cirrhosis. SUBJECTS AND METHODS: Ten
arterioportal shunts in eight patients, including four tumorous
and six nontumorous arterioportal shunts, were evaluated on T2-weighted
turbo spin-echo and T2(*)-weighted gradient-echo sequences before
and after administration of superparamagnetic iron oxide. Qualitatively,
the relative signal intensity of the arterioportal shunt compared
with that of the surrounding liver parenchyma was categorized
into three grades: high, slightly high, and not detected. Quantitatively,
signal-to-noise ratio, contrast-to-noise ratio, lesion-to-liver
contrast, and percentage enhancement were calculated and compared
between tumorous and nontumorous arterioportal shunts by a nonparametric
statistical test (Mann-Whitney test). RESULTS: Qualitatively,
all four tumorous arterioportal shunts appeared as areas of slightly
high or high intensity without and with superparamagnetic iron
oxide on T2-weighted turbo spin-echo images and changed from isointensity
to high intensity after the administration of superparamagnetic
iron oxide on T2(*)-weighted gradient-echo images. All nontumorous
arterioportal shunts except one could not be recognized without
or with superparamagnetic iron oxide on either sequence. Quantitatively,
with superparamagnetic iron oxide the contrast-to-noise ratio
and the lesion-to-liver contrast of the tumorous arterioportal
shunts were significantly higher than those of the nontumorous
arterioportal shunts. CONCLUSION: Tumorous arterioportal shunts
are seen as areas of reduced signal loss, whereas most nontumorous
arterioportal shunts are seen as areas of normal signal loss,
like the normal liver parenchyma. The difference is more marked
on T2(*)-weighted gradient-echo images than on T2-weighted turbo
spin-echo images.
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