Imaging discordance between hepatic angiography versus Tc-99m-MAA SPECT/CT: a case series, technical discussion and clinical implications.

Abstract

During pre-therapy evaluation for yttrium-90 (Y-90) radioembolization, it is uncommon to find severe imaging discordance between hepatic angiography versus technetium-99m-macroaggregated albumin (Tc-99m-MAA) single photon emission computed tomography with integrated low-dose CT (SPECT/CT). The reasons for severe imaging discordance are unclear, and literature is scarce. We describe 3 patients with severe imaging discordance, whereby tumor angiographic contrast hypervascularity was markedly mismatched to the corresponding Tc-99m-MAA SPECT/CT, and its clinical impact. The incidence of severe imaging discordance at our institution was 4% (3 of 74 cases). We postulate that imaging discordance could be due to a combination of 3 factors: (1) different injection rates between soluble contrast molecules versus Tc-99m-MAA; (2) different arterial flow hemodynamics between soluble contrast molecules versus Tc-99m-MAA; (3) eccentric release position of Tc-99m-MAA due to microcatheter tip location, inadvertently selecting non-target microparticle trajectories. Tc-99m-MAA SPECT/CT more accurately represents hepatic microparticle biodistribution than soluble contrast hepatic angiography and should be a key criterion in patient selection for Y-90 radioembolization. Tc-99m-MAA SPECT/CT provides more information than planar scintigraphy to guide radiation planning and clinical decision making. Severe imaging discordance at pre-therapy evaluation is ominous and should be followed up by changes to the final vascular approach during Y-90 radioembolization.

• Authors: Yung Hsiang Kao, Eik Hock Tan, Terence Kiat Beng Teo, Chee Eng Ng, Soon Whatt Goh
• Journal: Annals of nuclear medicine (Ann Nucl Med) Vol. 25 Issue 9 Pg. 669-76 (Nov 2011) ISSN: 1864-6433 [Electronic] Japan
• PMID: 21766243 (Publication Type: Case Reports, Comparative Study, Journal Article)

Chemical References

• Technetium Tc 99m Aggregated Albumin

Topics

• Aged, 80 and over
• Angiography (methods)
• Carcinoma, Hepatocellular (diagnostic imaging, pathology, physiopathology)
• Humans
• Liver (diagnostic imaging)
• Liver Neoplasms (diagnostic imaging, pathology, physiopathology)
• Male
• Middle Aged
• Multimodal Imaging (methods)
• Positron-Emission Tomography
• Technetium Tc 99m Aggregated Albumin
• Tomography, X-Ray Computed