Usefulness and pitfalls of MAA SPECT/CT in identifying digestive extrahepatic uptake when planning liver radioembolization

International audiencePURPOSE: Identifying gastroduodenal uptake of (99m)Tc-macroaggregated albumin (MAA), which is associated with an increased risk of ulcer disease, is a crucial part of the therapeutic management of patients undergoing radioembolization for liver tumours. Given this context, the use of MAA single photon emission computed tomography (SPECT)/CT may be essential, but the procedure has still not been thoroughly evaluated. The aim of this retrospective study was to determine the effectiveness of MAA SPECT/CT in identifying digestive extrahepatic uptake, while determining potential diagnostic pitfalls. METHODS: Overall, 139 MAA SPECT/CT scans were performed on 103 patients with different hepatic tumour types. Patients were followed up for at least 6 months according to standard requirements. RESULTS: Digestive, or digestive-like, uptake other than free pertechnetate was identified in 5.7% of cases using planar imaging and in 36.6% of cases using SPECT/CT. Uptake sites identified by SPECT/CT included the gastroduodenal region (3.6%), gall bladder (12.2%), portal vein thrombosis (6.5%), hepatic artery (6.5%), coil embolization site (2.1%) as well as falciform artery (5.0%). For 2.1% of explorations, a coregistration error between SPECT and CT imaging could have led to a false diagnosis by erroneously attributing an uptake site to the stomach or gall bladder, when the uptake actually occurred in the liver. CONCLUSION: SPECT/CT is more efficacious than planar imaging in identifying digestive extrahepatic uptake sites, with extrahepatic uptake observed in one third of scans using the former procedure. However, more than half of the uptake sites in our study were vascular in nature, without therapeutic implications. The risk of coregistration errors must also be kept in mind

Transarterial 90Yttrium Radioembolisation

none2noThe term transarteria radioembolisation includes those procedures in which intra-arterially injected radioactive microspheres are used for internal radiation purposes. This procedure aims to selectively target radiation to liver tumours and to limit the dose involving the normal liver parenchyma. The yttrium-90 microspheres delivered throught the hepatic artery are implanted into liver tumours in a ratio ranging from 3:1 to 20:1 as compared to a normal liver. A work-up, involving computed tomography scanning, contrast-enhanced magnetic resonance imaging and hepatic angiography, is essencial for assessing the appropriateness of yttrium-90 treatment for each patient. A simulation of the procedure, carried out with technetium-99 m-labelled macroaggregated albumin particles, which approximate the size of microsphere, is used to identify the shunting of microparticles to the lungs or the gastrointestinal tract, thus helping in patient selection. Excellent periprocedural care, discharge planning and follow-up are essential for assessing treatment response and ensuring thatthe short-term side effects of radioembolisation are adequately managed. The purpose of this chapter is to summarise the relevant recent results regarding technical aspect, dosimetric advanced, adverse events, safety and efficacy of radioembolisation in the treatment of hepatocellular carcinoma, intrahepatic cholangiocarcinoma and liver metastasis.noneCristina Mosconi; Rita GolfieriCristina Mosconi; Rita Golfier