Contrast- and non-contrast-enhanced ultrasonography (US) findings of hepatic metastasis from malignant pheochromocytoma/paraganglioma

Abstract

To evaluate the findings of hepatic metastases from malignant pheochromocytoma/paraganglioma on non-contrast-enhanced and contrast-enhanced ultrasonography (US) and compare them with other imaging modalities. US was performed on eight patients with 65 hepatic metastases. Non-contrast computed tomography (CT), meta-iodo-benzyl-guanidine scintigraphy ((123)I-MIBG), and fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) were also performed. Magnetic resonance imaging, including diffusion-weighted imaging (DWI), was performed on six patients. Forty of the 65 lesions (61.5%) were detected on non-contrast-enhanced US: 27 were hyperechoic (67.5%), 10 were hypoechoic (25.0%), and 3 (7.5%) were isoechoic. Sixteen of 17 lesions appeared hypervascular in the arterial phase of dynamic contrast-enhanced US. On delayed images, contrast-enhanced US demonstrated 64 of 65 metastatic tumors (98.5%), and 51 of them were delineated as enhancement defects. Non-contrast-enhanced CT revealed 61 (93.8%) of 65, FDG-PET revealed 44 (67.7%) of 65, and DWI revealed 30 (90.9%) of 33. On (123)I-MIBG scintigraphy, seven patients had abnormal uptakes in the liver, suggesting metastases. There were no significant differences between the detectability of US and other modalities. On contrast-enhanced US, nearly all hepatic metastases were delineated. Most lesions showed hypervascularity on dynamic contrast-enhanced US, suggesting the usefulness of this technique.