The purpose was to evaluate the potential of FDG–PET–CT and whole-body MRI (WB-MRI) as diagnostic triage methods for patients planned for radioembolisation of metastatic liver disease.

Materials and methods

135 patients with multifocal liver metastases were evaluated for potential palliative therapy with radioembolisation using 90-Yttrium microspheres. All patients were examined consecutively with FDG–PET–CT and WB-MRI for exclusion of relevant extra-hepatic tumor manifestations. All patients underwent 99mTc-albumine angiography followed by scintigraphy to exclude significant hepato-pulmonary shunting.

Results

Out of the 135 patients included into the pre-therapeutic diagnostic algorithm, 56% were eligible and received radioembolisation, while 44% could not be treated. In 91% the exclusion criteria was diagnosis of significant extra-hepatic metastatic disease. In 85% exclusion diagnosis was made concordantly by both FDG–PET–CT and WB-MRI, in 9% diagnosis was provided by PET–CT, in 6% by WB-MRI alone. Patient-based sensitivity for detection of extra-hepatic disease was 94% for PET–CT and 91% for WB-MRI. False-positive diagnosis of extrahepatic disease leading to exclusion for radioembolisation therapy was made in 2% of patients, in one patient by PET–CT and in one patient by WB-MRI alone. Overall, specificity for inclusion of radioembolisation therapy by combining both modalities was 99%. In 9% of patients angiographic diagnosis made radioembolisation impossible, in 7% solely the angiographic findings were decisive.

Conclusion

Both FDG–PET–CT and WB-MRI are efficient diagnostic triage methods for patients planned for radioembolisation of liver metastases. Overall, FDG–PET–CT shows a trend to higher diagnostic accuracy compared to WB-MRI and may be used as imaging method of choice as a standalone examination. In combination, both modalities exhibited high sensitivity for the diagnosis of extra-hepatic tumor manifestations and result in high specificity.

source: European Journal of Radiology