Direct relationship between cell density and FDG uptake in asymptomatic aortic aneurysm close to surgical threshold: An in vivo and in vitro study

Cecilia Marini, Silvia Morbelli, Riccardo Armonino, Giovanni Spinella, Mattia Riondato, Michela Massollo, Francesca Sarocchi, Bianca Pane, Carla Augeri, Luca Abete, Giorgio Ghigliotti, Daniela Palmieri, Francesco Fiz, Giuseppe Cittadini, Ezio Fulcheri, Domenico Palombo, Gianmario Sambuceti

Research output: Contribution to journalArticle

Abstract

Purpose: Conflicting results have been reported about the clinical value of fluorodeoxyglucose (FDG) imaging in predicting the risk of rupture of abdominal aortic aneurysm (AAA). The present study tests the hypothesis that FDG uptake is low in asymptomatic noninflammatory AAA due to the low cell density in aneurysmal walls. Methods: Positron emission tomography (PET)/CT imaging was performed in 12 consecutive candidates for AAA surgical repair and in 12 age- and sex-matched controls. At intervention, aneurysmal walls were cut into three sequential blocks. Block A was frozen to cut three 5-μm slices for incubation with 2-3 MBq of FDG for 5 min. Block C was first incubated with the same tracer solution for the same time and subsequently frozen to cut three 5-μm slices. Autoradiographic images were coregistered with immunohistochemical pictures of cell density, type and DNA synthesis as assessed on block B. Results: No visible uptake in abdominal aorta occurred in any patient or control subject. Immunohistochemistry documented a severe loss of wall structure, with low numbers of cells. Tracer retention directly correlated with overall cell density and with prevalence of cells synthesizing DNA. The metabolic nature of FDG uptake was confirmed by the selective effect of preliminary freezing that decreased tracer content by 90% in regions with high cell density and only by 34% in cold acellular areas. Conclusion: The loss of tissue structure and the marked decrease in cell density account for the low prevalence of positive findings at FDG PET imaging, at least in asymptomatic patients bearing AAAs whose diameter is close to surgical indication.

Original languageEnglish
Pages (from-to)91-101
Number of pages11
JournalEuropean Journal of Nuclear Medicine and Molecular Imaging
Volume39
Issue number1
DOIs
Publication statusPublished - Jan 2012

Keywords

  • Abdominal aortic aneurysm
  • Atherosclerosis
  • FDG uptake
  • Positron emission tomography/computed tomography

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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