Table 1.
Patient demographics at the time of the baseline PET/CT (total number of PET/CT examinations n = 101).
Fig 1.
Flow diagram displaying the numbers of patients screened, excluded, and included in the final study for suspected mycotic aortic aneurysms (MAA) in the first section. The second section shows the number of baseline and follow-up PET/CT (positron emission tomography/computed tomography) performed. Imaging diagnoses at baseline PET/CT are given in the third section, as well as the number of confirmed MAA at follow up (* notably, repetitive imaging in some patients with MAA accounts for the higher number as compared to baseline). Finally, the number of patients treated with antibiotics at the time of imaging is given in the bottom section.
Fig 2.
Number of baseline PET/CT with impact on patient management.
Bar graph of all baseline PET/CT examinations in 50 patients demonstrating the number of examinations with impact on patient management (confirmed: light gray bars; suspected: dark gray bars) and the number of misleading examinations (black bars) with regard to different referral questions for PET/CT (first bar: mycotic aortic aneurysm (MAA); second bar: MAA, other infection or lymphoma; third bar: vascular graft infection (VGI); fourth bar: various referral questions).
Fig 3.
PET/CT with confirmed impact on management.
A 71-year old woman was referred for PET/CT for staging of gastric cancer and with the question for an infectious aneurysm. The PET/CT examination (A: maximum intensity reconstruction, B: fused axial PET/CT image, and C: axial non-enhanced CT image) showed a FDG-avid mass adjacent to the abdominal aorta (white arrows in A and B). Both readers correctly rated the finding to be an infectious aneurysm; no gastric cancer was detected. The diagnosis was confirmed after biopsy (MAA caused by Coxiella burnetii) and the patient was treated with endovascular aortic repair and partial gastrectomy and lymphadenectomy. The patient was treated with antibiotics for 784 days and did not show any sign of recurrence at the last clinical visit 293 days after the end of antimicrobial therapy.
Fig 4.
PET/CT with confirmed impact on management of an incidental finding.
A 61-year old man was presented with recurrent episodes of fever and an elevated C-reactive protein level (154 mg/L). A PET/CT with the question for mycotic aortic aneurysm (MAA) or recurrence of lymphoma was acquired (A: maximum intensity reconstruction, B, C and D: fused axial PET/CT images). Lymphoma recurrence and MAA were correctly ruled out by both readers (no increased uptake in the abdominal aneurysm (white arrow in C)), as confirmed by long-term clinical follow-up. As an incidental finding with impact on patient management, PET/CT detected arteritis of the peripheral arteries (as demonstrated in the axillary (upper black arrows in A and white arrows in B) and popliteal arteries (lower black arrows in A and white arrows in D)). At the last clinical visit (826 days after PET/CT) the patient had continuous therapy with glucocorticoids. The patient was doing fine with no clinical signs of recurrent lymphoma, infection or inflammation.
Table 2.
Impact on patient management of baseline PET/CT scans with the referral question: Mycotic aortic aneurysm (n = 18).
Table 3.
Impact on patient management of baseline PET/CT scans with the referral question: MAA, other infection or lymphoma (n = 14).
Table 4.
Impact on patient management of baseline PET/CT scans with the referral question: Vascular graft infection (n = 8).
Table 5.
Impact on patient management of baseline PET/CT scans with the various referral questions (n = 10).
Fig 5.
Number of follow-up PET/CT with impact on patient management.
Bar graph of all follow-up PET/CT examinations (n = 51) demonstrating the number of examinations with impact on patient management (confirmed: light gray bars; suspected: dark gray bars) and the number of misleading examinations (black bars) with regard to different referral questions for PET/CT (first bar: follow-up of mycotic aortic aneurysm (MAA) or vascular graft infection (VGI); second bar: VGI; third bar: various referral questions).
Fig 6.
PET/CT with misleading diagnosis.
The first follow-up PET/CT examination (A: maximum intensity reconstruction, B: fused axial PET/CT image, and C: axial non-enhanced CT image) of a 64-year old man was performed four months after the initial diagnosis of a mycotic aortic aneurysm, four months after the beginning of antimicrobial treatment and three months after thoracic endovascular aortic repair and supra-aortic debranching. Focal FDG accumulation adjacent to the graft (white arrows in A and B) was detected and rated positive for a remaining vascular graft infection by both readers. However, antimicrobial treatment was stopped 17 days after the PET/CT examination and no signs of recurrent infection was detected on clinical follow-up visits (the last one 667 days after the end of treatment). Therefore, PET/CT was rated “misleading”.
Table 6.
Impact on patient management of follow-up PET/CT scans with the referral question: Follow-up MAA/VGI (n = 32).
Table 7.
Impact on patient management of follow-up PET/CT scans with the referral question: VGI (n = 5).
Table 8.
Impact on patient management of follow-up PET/CT scans with the various referral questions (n = 14).