Radioembolization with Y-90 Glass Microspheres: Do We Really Need SPECT-CT to Identify Extrahepatic Shunts?

Area of Science:

• Interventional Radiology
• Nuclear Medicine
• Hepatobiliary Malignancies

Background:

• Selective Internal Radiation Therapy (SIRT) with 90yttrium (Y-90) is a key treatment for unresectable liver cancers.
• Complications can arise from nontarget embolization of extrahepatic tissues due to vascular shunting.
• Accurate diagnosis of these shunts is crucial for safe and effective SIRT.

Purpose of the Study:

• To evaluate the diagnostic reliability of hepatic digital subtraction angiography (DSA) for extrahepatic shunts.
• To determine if SPECT/CT imaging provides additional diagnostic information beyond DSA for these shunts.
• To assess the impact of shunt detection on SIRT treatment decisions.

Main Methods:

• Retrospective analysis of 825 patients undergoing SIRT for liver malignancies.
• Hepatic DSA was performed, with coilembolization of identified shunt vessels.
• Technetium-99m-labeled human serum albumin (HSA) SPECT/CT was used to identify extrahepatic shunts.

Main Results:

• SPECT/CT detected unexpected extrahepatic HSA uptake in 6.5% of patients (54/825).
• Additional shunts were identified and treated in 22 patients after repeat DSA.
• 20 patients with persistent extrahepatic uptake on repeat SPECT/CT did not receive SIRT.

Conclusions:

• Hepatic DSA is effective in identifying most extrahepatic shunts before Y-90 therapy.
• SPECT/CT imaging is valuable for detecting additional shunts not visualized on DSA.
• Integrating SPECT/CT improves the safety and accuracy of pre-SIRT shunt assessment.