The aim of this study was to compare the performance of double-contrast magnetic resonance imaging (DC-MRI) with the sequential use of superparamagnetic
iron oxide (
SPIO) and
gadolinium-diethylenetriaminepentaacetic
acid (
Gd-DTPA)
contrast agents compared with unenhanced MRI and
SPIO-enhanced MRI (
SPIO-MRI) in the study of the cirrhotic liver. Special attention was paid to cases in which alterations of liver uptake and distribution of the
SPIO contrast medium [
SPIO-liver uptake and distribution alterations (
SPIO-LUDA)] could lead to diagnostic errors at
SPIO-MRI.
MATERIALS AND METHODS: We used DC-MRI to study 67 patients suffering from
hepatic cirrhosis and on a waiting list for
liver transplant. The study was performed with a 1.5-Tesla device and characterised by three phases: the first phase without
contrast material (unenhanced MRI), the second after the administration of
ferumoxides (
SPIO-MRI), and the third, a double-contrast study following the injection of a bolus of paramagnetic
contrast material (DC-MRI). The sensitivity of unenhanced MRI,
SPIO-MRI and DC-MRI in identifying and characterising hepatic focal lesions was assessed, together with the diagnostic increment of one technique with respect to the others. The gold standard was histological confirmation in 38 cases and clinical-radiological follow-up in all cases. Liver function, kidney function, blood tests and urinalysis were performed in all patients 24-48 h before and after the MRI examination.
RESULTS: In 14/67 cases (20.8%),
SPIO-LUDA were present, which posed a limitation to the
SPIO-MRI examination. Focal lesions were absent in 44 patients, and the action of the
ferumoxides was reduced by the presence of
SPIO-LUDA in nine cases. There were five cases of confluent
fibrosis, two of decompensated
cirrhosis, one of vascular
thrombosis, and one of
scarring in a patient who had undergone hepatic resection for
hepatocellular carcinoma (HCC). In all these cases, completion of the MR examination with the DC technique clarified the MR picture, confirming the absence of focal lesions. Twenty-three patients had a total of 68 lesions, which consisted of 37 dysplastic nodules (DN), 19 HCC nodules, two relapses of HCC following chemoembolisation, two HCC associated with portal
thrombosis, one
cancer-
cirrhosis, two angiomas and five small
cysts.
SPIO-LUDA were present in five patients, thus limiting the identification, characterisation or assessment of the real size of the lesions.
SPIO-LUDA were the result of vascular
thrombosis in one case and
fibrosis in four cases. In all of these cases, DC-MRI proved useful for diagnosis. The sensitivity of unenhanced MRI,
SPIO-MRI and DC-MRI for lesion detection was 57.3%, 67.6% and 75%, respectively. The results obtained in the characterisation of the lesions were 20.5%, 63.2% and 73.5% for unenhanced MRI,
SPIO-MRI and DC-MRI, respectively. The diagnostic increment of
SPIO-MRI over unenhanced MRI for lesion identification and characterisation was 9% and 42.7%, respectively, whereas the diagnostic increment of DC-MRI over
SPIO-MRI was 7.4% and 10.3%, respectively.
CONCLUSIONS: In our study, the combined use of two
contrast agents, negative and positive, provided greater diagnostic confidence and caused no side effects in the patients.