Appearance of aseptic vascular grafts after endovascular aortic repair on [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography

• Published in: World journal of radiology 2023-08, Vol.15 (8), p.241-249
• Main Authors: Bennett, Paige, Tomas, Maria Bernadette, Koch, Christopher F, Nichols, Kenneth J, Palestro, Christopher J
• Format: Article
• Language: English
• Subjects: Retrospective Study
• ISSN: 1949-8470; 1949-8470
• DOI: 10.4329/wjr.v15.i8.241

BACKGROUNDDiagnosis of prosthetic vascular graft infection with [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) allows for early detection of functional changes associated with infection, based on increased glucose utilization by activated macrophages and granulocytes. Aseptic vascular grafts, like all foreign bodies, can stimulate an inflammatory response, which can present as increased activity on 18F-FDG PET/CT. Consequently, distinguishing aseptic inflammation from graft infection, though important, can be difficult. In the case of endovascular aneurysm repair (EVAR), a minimally invasive procedure involving the transfemoral insertion of an endoprosthetic stent graft, the normal postoperative appearance of these grafts on 18F-FDG PET/CT can vary over time, potentially confounding study interpretation. AIMTo investigate the visual, semiquantitative, and temporal characteristics of aseptic vascular grafts in patients status post EVAR. METHODSIn this observational retrospective cohort study, patients with history of EVAR who underwent 18F-FDG PET/CT for indications other than infection were identified retrospectively. All patients were asymptomatic for graft infection - no abdominal pain, fever of unknown origin, sepsis, or leukocytosis - at the time of imaging and for ≥ 2 mo after each PET/CT. Imaging studies such as CT for each patient were also reviewed, and any patients with suspected or confirmed vascular graft infection were excluded. One hundred two scans performed on 43 patients (34 males; 9 females; age = 77 ± 8 years at the time of the final PET/CT) were retrospectively reviewed. All 43 patients had an abdominal aortic (AA) vascular graft, 40 patients had a right iliac (RI) limb graft, and 41 patients had a left iliac (LI) limb graft. Twenty-two patients had 1 PET/CT and 21 patients had from 2 to 9 PET/CTs. Grafts were imaged between 2 mo to 168 mo (about 14 years) post placement. Eight grafts were imaged within 6 mo of placement, including three that were imaged within three months of placement. The mean interval between graft placement and PET/CT for all 102 scans was 51 ± 39 mo. PET/CT data was reconstructed with region-of-interest analysis of proximal, mid and distal portions of the grafts and background ascending aorta. Maximum standardized uptake value (SUVmax) was recorded for each region. SUVmax-to-background uptake ratios (URs) were calculated. Visual assessment was performed using a 2-pattern