18F-FDG PET-CT in Suspected Prosthetic Vascular Graft Infection Jean-Baptiste Pinaquy, Charles Cazanave, Laurent Stecken, Laurence Bordenave, Ghoufrane Tlili, and Xavier Berard, Bordeaux, Pessac, France
Background: Diagnosis of prosthetic vascular graft infections is a clinical challenge, and surgical therapy is associated with comorbidity. Therefore, accurate diagnostic methods are required for their optimal management. Methods: A 61-year-old-patient presented with erysipelas of the right lower limb 7 months after receiving a hybrid femoropopliteal bypass composed of a saphenous vein distally and external supported polytetrafluoroethylene proximally. He had been first treated for suspicious of septic arterial thrombosis or false aneurysm with antibiotics. A computed tomography (CT) angiogram was performed to detect any potential infection of the bypass and to explore erysipelas. It revealed a subcutaneous infiltration and an infiltration of the right groin but no anastomotic pseudoaneurysm or thrombosis of the bypass. The 2-[18F]-fluoro-2-desoxy-D-glucose positron emission tomography (18F-FDG PET) evidenced a significant uptake of cutaneous and subcutaneous tissue but no uptake on the vascular prosthetic graft. Therefore, the bypass was considered as noninfected and antibiotics were continued for 3 months. A physical examination on antibiotic cessation revealed a nonerythematous thigh with a C-reactive protein level significantly decreased to 36 mg/L and a normal white blood cell count. A PET scan confirmed this clinical improvement as attested by a dramatically decreased uptake of cutaneous and subcutaneous tissues and still no uptake of the graft. Conclusions: In conclusion, this case highlights the role that 18F-FDG PET-CT may play in excluding suspected prosthetic graft infection, thanks to its high sensitivity and in avoiding needless revision surgery with subsequent comorbidities.
Erysipelas is a common, acute, infectious skin disease. The usual causative agents are group A b-hemolytic streptococci. Streptococci of groups B, C, or G may also be isolated and Staphylococcus aureus and other bacteria.1e3 The pathogen usually enters through a site where the skin barrier is not fully functional. Thus, tinea pedis, ulcus cruris, minor injuries, and surgical procedures often lead to the infection.4
Department of Nuclear Medicine, CHU Bordeaux, Pessac, France. Correspondence to: Jean-Baptiste Pinaquy, Department of Nuclear Medicine, CHU Bordeaux, Avenue Magellan, Pessac 33604, France; E-mail: [email protected] Ann Vasc Surg 2015; 29: 361.e13e361.e15 http://dx.doi.org/10.1016/j.avsg.2014.08.017 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: April 28, 2014; manuscript accepted: August 14, 2014; published online: November 5, 2014.
CASE REPORT A 61-year-old-patient presented with erysipelas (Fig. 1) of the right lower limb 7 months after receiving a hybrid femoropopliteal bypass composed of a saphenous vein distally and external supported polytetrafluoroethylene proximally. Blood test showed increased C-reactive protein (CRP) of 256 mg/L and a moderately elevated white blood cell (WBC) count (9.8 109/L). He had first been treated with antibiotics (amikacin 500 mg 3, amoxicillin and/or clavulanate 1 g, and vancomycin 1g 2 each day) for suspicion of septic arterial thrombosis or false aneurysm. Duplex ultrasound revealed deep vein thrombosis of the lower limb, and testicular ultrasound showed a superficial subcutaneous abscess. A computed tomography angiogram (CTA) was performed to detect any potential infection of the bypass and to explore the erysipelas. It revealed a subcutaneous infiltration and an infiltration of the right groin but no anastomotic pseudoaneurysm or thrombosis of the bypass.
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Fig. 1. Physical examination reveals an erythematous thigh.
Annals of Vascular Surgery
Fig. 3. After 3 months of antibiotic therapy, physical examination shows a nonerythematous thigh.
Fig. 2. First FDG-PET shows a superficial subcutaneous abscess (thin arrow), erysipelas of lower limb (large arrow), and no prosthetic graft uptake (head arrow) on
max intensity projection image (A), axial scintigraphy slices (B), and fusion slices (C).
2-[18F]-fluoro-2-desoxy-D-glucose positron emission tomography (FDG-PET) evidenced a significant uptake of cutaneous and subcutaneous tissue but no uptake on the vascular prosthetic graft (Fig. 2). Therefore, the bypass was considered as noninfected, and antibiotics were continued for 3 months. A physical examination on antibiotic cessation revealed a nonerythematous thigh (Fig. 3) with a CRP level significantly decreased to 36 mg/L and a normal WBC count. A PET scan confirmed this clinical improvement as attested by a dramatically decreased uptake of cutaneous and subcutaneous tissues (Fig. 4) and still no uptake of the graft.
DISCUSSION CTA is the gold standard examination for the diagnosis of vascular prosthetic infection with a sensitivity and specificity rate close to 100% in the event of acute infection. However, CTA is less accurate in low-grade infection, with an overall sensitivity of only 55.5%.5 Two recent studies that compared FDG-PET and CTA in 33 and 25 patients, respectively, also found CTA to have a sensitivity of less than 60% for chronic infection,6,7 whereas
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Case reports 361.e15
Fig. 4. Comparison between pretherapeutic (A, B) and posttherapeutic (C, D) FDG-PET showing the disappearance of subcutaneous uptake and still no suspicious uptake of prosthetic graft.
FDG-PET had an excellent sensitivity and negative predictive value, which were about 90% in both studies. As in our case, those studies demonstrate the value of FDG-PET for ruling out any graft infection and avoiding needless surgery. In conclusion, this case highlights the role that 18 F-FDG PET-CT may play in excluding suspected prosthetic graft infection, thanks to its high sensitivity and in avoiding needless revision surgery with subsequent comorbidities. REFERENCES 1. Krasagakis K, Valachis A, Maniatakis P, et al. Analysis of epidemiology, clinical features and management of erysipelas. Int J Dermatol 2010;49:1012e7.
2. Pavlotsky F, Amrani S, Trau H. Recurrent erysipelas: risk factors. J Dtsch Dermatol Ges 2004;2:89e95. 3. Koster JB, Kullberg BJ, van der Meer JW. Recurrent erysipelas despite antibiotic prophylaxis: an analysis from case studies. Neth J Med 2007;65:89e94. 4. Dupuy A, Benchikhi H, Roujeau JC, et al. Risk factors for erysipelas of the leg (cellulitis): case-control study. BMJ 1999;318:1591e4. 5. Fiorani P, Speziale F, Rizzo L, et al. Detection of aortic graft infection with leukocytes labeled with technetium 99m-hexametazime. J Vasc Surg 1993;17:87e95. 6. Bruggink JL, Glaudemans AW, Saleem BR, et al. Accuracy of FDG-PET-CT in the diagnostic work-up of vascular prosthetic graft infection. Eur J Vasc Endovasc Surg 2010;40:348e54. 7. Fukuchi K, Ishida Y, Higashi M, et al. Detection of aortic graft infection by fluorodeoxyglucose positron emission tomography: comparison with computed tomographic findings. J Vasc Surg 2005;42:919e25.
Background: Diagnosis of prosthetic vascular graft infections is a clinical challenge, and surgical therapy is associated with comorbidity. Therefore, accurate diagnostic methods are required for their optimal management. Methods: A 61-year-old-patient presented with erysipelas of the right lower limb 7 months after receiving a hybrid femoropopliteal bypass composed of a saphenous vein distally and external supported polytetrafluoroethylene proximally. He had been first treated for suspicious of septic arterial thrombosis or false aneurysm with antibiotics. A computed tomography (CT) angiogram was performed to detect any potential infection of the bypass and to explore erysipelas. It revealed a subcutaneous infiltration and an infiltration of the right groin but no anastomotic pseudoaneurysm or thrombosis of the bypass. The 2-[18F]-fluoro-2-desoxy-D-glucose positron emission tomography (18F-FDG PET) evidenced a significant uptake of cutaneous and subcutaneous tissue but no uptake on the vascular prosthetic graft. Therefore, the bypass was considered as noninfected and antibiotics were continued for 3 months. A physical examination on antibiotic cessation revealed a nonerythematous thigh with a C-reactive protein level significantly decreased to 36 mg/L and a normal white blood cell count. A PET scan confirmed this clinical improvement as attested by a dramatically decreased uptake of cutaneous and subcutaneous tissues and still no uptake of the graft. Conclusions: In conclusion, this case highlights the role that 18F-FDG PET-CT may play in excluding suspected prosthetic graft infection, thanks to its high sensitivity and in avoiding needless revision surgery with subsequent comorbidities.
Erysipelas is a common, acute, infectious skin disease. The usual causative agents are group A b-hemolytic streptococci. Streptococci of groups B, C, or G may also be isolated and Staphylococcus aureus and other bacteria.1e3 The pathogen usually enters through a site where the skin barrier is not fully functional. Thus, tinea pedis, ulcus cruris, minor injuries, and surgical procedures often lead to the infection.4
Department of Nuclear Medicine, CHU Bordeaux, Pessac, France. Correspondence to: Jean-Baptiste Pinaquy, Department of Nuclear Medicine, CHU Bordeaux, Avenue Magellan, Pessac 33604, France; E-mail: [email protected] Ann Vasc Surg 2015; 29: 361.e13e361.e15 http://dx.doi.org/10.1016/j.avsg.2014.08.017 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: April 28, 2014; manuscript accepted: August 14, 2014; published online: November 5, 2014.
CASE REPORT A 61-year-old-patient presented with erysipelas (Fig. 1) of the right lower limb 7 months after receiving a hybrid femoropopliteal bypass composed of a saphenous vein distally and external supported polytetrafluoroethylene proximally. Blood test showed increased C-reactive protein (CRP) of 256 mg/L and a moderately elevated white blood cell (WBC) count (9.8 109/L). He had first been treated with antibiotics (amikacin 500 mg 3, amoxicillin and/or clavulanate 1 g, and vancomycin 1g 2 each day) for suspicion of septic arterial thrombosis or false aneurysm. Duplex ultrasound revealed deep vein thrombosis of the lower limb, and testicular ultrasound showed a superficial subcutaneous abscess. A computed tomography angiogram (CTA) was performed to detect any potential infection of the bypass and to explore the erysipelas. It revealed a subcutaneous infiltration and an infiltration of the right groin but no anastomotic pseudoaneurysm or thrombosis of the bypass.
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Fig. 1. Physical examination reveals an erythematous thigh.
Annals of Vascular Surgery
Fig. 3. After 3 months of antibiotic therapy, physical examination shows a nonerythematous thigh.
Fig. 2. First FDG-PET shows a superficial subcutaneous abscess (thin arrow), erysipelas of lower limb (large arrow), and no prosthetic graft uptake (head arrow) on
max intensity projection image (A), axial scintigraphy slices (B), and fusion slices (C).
2-[18F]-fluoro-2-desoxy-D-glucose positron emission tomography (FDG-PET) evidenced a significant uptake of cutaneous and subcutaneous tissue but no uptake on the vascular prosthetic graft (Fig. 2). Therefore, the bypass was considered as noninfected, and antibiotics were continued for 3 months. A physical examination on antibiotic cessation revealed a nonerythematous thigh (Fig. 3) with a CRP level significantly decreased to 36 mg/L and a normal WBC count. A PET scan confirmed this clinical improvement as attested by a dramatically decreased uptake of cutaneous and subcutaneous tissues (Fig. 4) and still no uptake of the graft.
DISCUSSION CTA is the gold standard examination for the diagnosis of vascular prosthetic infection with a sensitivity and specificity rate close to 100% in the event of acute infection. However, CTA is less accurate in low-grade infection, with an overall sensitivity of only 55.5%.5 Two recent studies that compared FDG-PET and CTA in 33 and 25 patients, respectively, also found CTA to have a sensitivity of less than 60% for chronic infection,6,7 whereas
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Fig. 4. Comparison between pretherapeutic (A, B) and posttherapeutic (C, D) FDG-PET showing the disappearance of subcutaneous uptake and still no suspicious uptake of prosthetic graft.
FDG-PET had an excellent sensitivity and negative predictive value, which were about 90% in both studies. As in our case, those studies demonstrate the value of FDG-PET for ruling out any graft infection and avoiding needless surgery. In conclusion, this case highlights the role that 18 F-FDG PET-CT may play in excluding suspected prosthetic graft infection, thanks to its high sensitivity and in avoiding needless revision surgery with subsequent comorbidities. REFERENCES 1. Krasagakis K, Valachis A, Maniatakis P, et al. Analysis of epidemiology, clinical features and management of erysipelas. Int J Dermatol 2010;49:1012e7.
2. Pavlotsky F, Amrani S, Trau H. Recurrent erysipelas: risk factors. J Dtsch Dermatol Ges 2004;2:89e95. 3. Koster JB, Kullberg BJ, van der Meer JW. Recurrent erysipelas despite antibiotic prophylaxis: an analysis from case studies. Neth J Med 2007;65:89e94. 4. Dupuy A, Benchikhi H, Roujeau JC, et al. Risk factors for erysipelas of the leg (cellulitis): case-control study. BMJ 1999;318:1591e4. 5. Fiorani P, Speziale F, Rizzo L, et al. Detection of aortic graft infection with leukocytes labeled with technetium 99m-hexametazime. J Vasc Surg 1993;17:87e95. 6. Bruggink JL, Glaudemans AW, Saleem BR, et al. Accuracy of FDG-PET-CT in the diagnostic work-up of vascular prosthetic graft infection. Eur J Vasc Endovasc Surg 2010;40:348e54. 7. Fukuchi K, Ishida Y, Higashi M, et al. Detection of aortic graft infection by fluorodeoxyglucose positron emission tomography: comparison with computed tomographic findings. J Vasc Surg 2005;42:919e25.
