Purpose: A well-known complication of endovascular aortic aneurysm repair (EVAR) is endoleak,
which can lead to sac expansion thus at risk of rupture. Subtraction CT iodine mapping
is a new application of computed tomography (CT) technology that can be used as an
adjunctive diagnostic tool for endoleak. This study explores the utility of iodine
mapping as a tool for the diagnosis of endoleak.
Materials and Methods: A single-center prospective pilot study of 27 consecutive EVAR patients was conducted.
Iodine mapping of subtraction CT technology was compared with traditional triple-phase
CT angiography, for the detection of endoleak. Two blinded radiologists interpreted
triple-phase CT angiograms compared with subtraction CT iodine mapping overlay in
axial imaging. Self-scored (1 to 5) confidence was analyzed in the diagnosis of endoleak.
Results: Majority of identified endoleaks were Type II. Reader 1 had very good agreeability
between triple-phase and iodine mapping (κ = 0.92) and identified 1 additional endoleak
with iodine mapping. Self-scored confidence in detecting if endoleak present or not
was 4.6/5 for triple phase and 4.9/5 for iodine mapping (p = 0.18). Reader 2 had good agreeability between triple-phase and iodine mapping (κ = 0.71)
and identified 2 additional endoleaks with iodine mapping. Self-scored confidence
in detecting if endoleak present or not was 4.5/5 for triple phase and 4.6/5 for iodine
mapping (p = 0.51).
Conclusion: Our pilot study demonstrates subtraction CT iodine mapping is a useful imaging modality
adjunct in the diagnosis of endoleak following EVAR; particularly in re-intervention
cases which have complex sac artifact. Further validation studies with larger cohorts
would be beneficial.
