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Aortic Prosthetic Graft Infections: Radiologic Manifestations and Implications for Management¹

¹ From the Department of Radiology, Veterans Affairs Medical Center, 4101 Woolworth Ave, Omaha, NE 68105 (D.F.O., J.A.S.); the Radiology Service, Veterans Administration Medical Center, Gainesville, Fla (R.F.L.); and the Departments of Radiology (W.C.C., J.L.F., T.C.G., T.C.M.) and Surgery (T.J.L.), University of Nebraska Medical Center, Omaha. Recipient of a Certificate of Merit award for a scientific exhibit at the 1994 RSNA scientific assembly. Received August 17, 1998; revision requested October 19; final revision received November 8, 1999; accepted November 9. Address correspondence to D.F.O. (e-mail: dorton@unmc.edu).

View larger version (112K): [in a new window]   Figure 1.   Normal findings in a patient with abdominal pain 1 week after elective aneurysm repair. CT scan shows air around the aortic graft (arrow). The abdominal pain subsided, with an otherwise uneventful postoperative course.

View larger version (136K): [in a new window]   Figure 2.   Normal findings in an 87-year-old woman with spiking fevers 1 week after repair of a ruptured aortic aneurysm. CT scan shows perigraft fluid and air (arrowheads), which are within normal limits for this early postoperative period. The ascites was transudative, and the culture was negative. The fevers were due to a lung abscess (not shown).

View larger version (123K): [in a new window]   Figure 3a.   Perigraft air secondary to graft infection in an asymptomatic patient. The patient originally presented with anemia and a hemoglobin level of 7 g/dL (70 g/L). Because of the possibility of an aortoenteric fistula (the patient had a history of duodenal ulcer), endoscopy was performed but showed no evidence of an aortoenteric fistula. (a) CT scan shows perigraft air (arrowhead), which was an incidental finding. Because the patient had undergone surgery nearly 2 years earlier, the diagnosis of graft infection was almost certain; however, owing to the lack of symptoms, a gallium scan was obtained. (b) Gallium scan shows increased uptake at the mid-abdominal aorta (arrows), thus confirming the diagnosis of infection. Cultures of the graft showed growth of Citrobacter diversus.

View larger version (167K): [in a new window]   Figure 3b.   Perigraft air secondary to graft infection in an asymptomatic patient. The patient originally presented with anemia and a hemoglobin level of 7 g/dL (70 g/L). Because of the possibility of an aortoenteric fistula (the patient had a history of duodenal ulcer), endoscopy was performed but showed no evidence of an aortoenteric fistula. (a) CT scan shows perigraft air (arrowhead), which was an incidental finding. Because the patient had undergone surgery nearly 2 years earlier, the diagnosis of graft infection was almost certain; however, owing to the lack of symptoms, a gallium scan was obtained. (b) Gallium scan shows increased uptake at the mid-abdominal aorta (arrows), thus confirming the diagnosis of infection. Cultures of the graft showed growth of Citrobacter diversus.

View larger version (110K): [in a new window]   Figure 4a.   Aortoenteric fistula in a patient with new-onset heme-positive stools and a history of aortic repair. (a) CT scan shows gas near the beginning of the graft (black arrowhead). The duodenum is closely adjacent (white arrowhead). (b) Contiguous CT scan obtained inferior to a shows perigraft air (white arrow) and the collapsed native aortic bed posterior to it (black arrow). Cultures of the graft were negative.

View larger version (112K): [in a new window]   Figure 4b.   Aortoenteric fistula in a patient with new-onset heme-positive stools and a history of aortic repair. (a) CT scan shows gas near the beginning of the graft (black arrowhead). The duodenum is closely adjacent (white arrowhead). (b) Contiguous CT scan obtained inferior to a shows perigraft air (white arrow) and the collapsed native aortic bed posterior to it (black arrow). Cultures of the graft were negative.

View larger version (107K): [in a new window]   Figure 5.   Normal perigraft ring. CT scan shows perigraft tissues that are no more than 5 mm thick (arrows).

View larger version (112K): [in a new window]   Figure 6a.   Normal early postoperative findings. (a) CT scan shows an area of attenuation around the graft (arrow), which represents residual fluid and hematoma. A small amount of air is also present. The patient had an uneventful postoperative course. (b) CT scan obtained 4 months later shows complete resolution of the perigraft fluid and hematoma.

View larger version (129K): [in a new window]   Figure 6b.   Normal early postoperative findings. (a) CT scan shows an area of attenuation around the graft (arrow), which represents residual fluid and hematoma. A small amount of air is also present. The patient had an uneventful postoperative course. (b) CT scan obtained 4 months later shows complete resolution of the perigraft fluid and hematoma.

View larger version (102K): [in a new window]   Figure 7.   Perigraft fluid collection in the left groin in a patient with persistent fever and elevated WBC count 4 months after surgery. CT demonstrated a persistent fluid collection around the graft. Because an infection could not be ruled out, CT-guided aspiration was performed. CT scan shows aspiration of the fluid collection, which demonstrated no bacterial growth but abundant WBCs. The fluid collection eventually showed growth of Campylobacter fetus. The patient and surgeon opted for treatment with antibiotics and close follow-up, which proved successful in the long term.

View larger version (104K): [in a new window]   Figure 8a.   Persistently culture negative, slowly progressive graft infection in a patient with a draining left groin mass 1 year after placement of an aortobifemoral graft for peripheral vascular disease. Angiography demonstrated no pseudoaneurysm. (a) CT scan obtained March 23, 1987, shows perigraft soft-tissue attenuation extending to the skin (arrowhead). (b) CT scan obtained May 13, 1988 (one of a number of follow-up CT scans), shows a small perigraft fluid collection and enhancing soft-tissue attenuation around the graft (arrowhead), findings consistent with perigraft infection. Fluid aspiration was positive for WBCs, but the culture was negative. In July 1989, the left limb of the graft was removed because it was infected and unresponsive to conservative therapy. In August 1989, the patient was readmitted for elective left axillofemoral bypass. (c) Follow-up CT scan obtained November 14, 1989, shows a fluid collection around the axillofemoral graft, which was positive for WBCs but negative at culture. (d) CT scan obtained December 17, 1989, shows persistence of the fluid collection and extension to the left groin (arrowhead). (e) CT scan obtained August 13, 1991, shows fluid around the right limb of the aortic bifurcation graft (arrow). This finding prompted excision of the entire aortic graft and placement of a right axillofemoral graft. (f) CT scan obtained October 4, 1991, shows persistent fluid around the left axillofemoral graft (arrow), but the graft remained uninfected. Subsequently, the left axillofemoral graft was removed and a femoral-femoral graft was placed. The infection was presumed to be due to S epidermidis on the basis of the clinical course and the multiple negative cultures, which are characteristic of slime-producing organisms such as S epidermidis.

View larger version (105K): [in a new window]   Figure 8b.   Persistently culture negative, slowly progressive graft infection in a patient with a draining left groin mass 1 year after placement of an aortobifemoral graft for peripheral vascular disease. Angiography demonstrated no pseudoaneurysm. (a) CT scan obtained March 23, 1987, shows perigraft soft-tissue attenuation extending to the skin (arrowhead). (b) CT scan obtained May 13, 1988 (one of a number of follow-up CT scans), shows a small perigraft fluid collection and enhancing soft-tissue attenuation around the graft (arrowhead), findings consistent with perigraft infection. Fluid aspiration was positive for WBCs, but the culture was negative. In July 1989, the left limb of the graft was removed because it was infected and unresponsive to conservative therapy. In August 1989, the patient was readmitted for elective left axillofemoral bypass. (c) Follow-up CT scan obtained November 14, 1989, shows a fluid collection around the axillofemoral graft, which was positive for WBCs but negative at culture. (d) CT scan obtained December 17, 1989, shows persistence of the fluid collection and extension to the left groin (arrowhead). (e) CT scan obtained August 13, 1991, shows fluid around the right limb of the aortic bifurcation graft (arrow). This finding prompted excision of the entire aortic graft and placement of a right axillofemoral graft. (f) CT scan obtained October 4, 1991, shows persistent fluid around the left axillofemoral graft (arrow), but the graft remained uninfected. Subsequently, the left axillofemoral graft was removed and a femoral-femoral graft was placed. The infection was presumed to be due to S epidermidis on the basis of the clinical course and the multiple negative cultures, which are characteristic of slime-producing organisms such as S epidermidis.

View larger version (102K): [in a new window]   Figure 8c.   Persistently culture negative, slowly progressive graft infection in a patient with a draining left groin mass 1 year after placement of an aortobifemoral graft for peripheral vascular disease. Angiography demonstrated no pseudoaneurysm. (a) CT scan obtained March 23, 1987, shows perigraft soft-tissue attenuation extending to the skin (arrowhead). (b) CT scan obtained May 13, 1988 (one of a number of follow-up CT scans), shows a small perigraft fluid collection and enhancing soft-tissue attenuation around the graft (arrowhead), findings consistent with perigraft infection. Fluid aspiration was positive for WBCs, but the culture was negative. In July 1989, the left limb of the graft was removed because it was infected and unresponsive to conservative therapy. In August 1989, the patient was readmitted for elective left axillofemoral bypass. (c) Follow-up CT scan obtained November 14, 1989, shows a fluid collection around the axillofemoral graft, which was positive for WBCs but negative at culture. (d) CT scan obtained December 17, 1989, shows persistence of the fluid collection and extension to the left groin (arrowhead). (e) CT scan obtained August 13, 1991, shows fluid around the right limb of the aortic bifurcation graft (arrow). This finding prompted excision of the entire aortic graft and placement of a right axillofemoral graft. (f) CT scan obtained October 4, 1991, shows persistent fluid around the left axillofemoral graft (arrow), but the graft remained uninfected. Subsequently, the left axillofemoral graft was removed and a femoral-femoral graft was placed. The infection was presumed to be due to S epidermidis on the basis of the clinical course and the multiple negative cultures, which are characteristic of slime-producing organisms such as S epidermidis.

View larger version (96K): [in a new window]   Figure 8d.   Persistently culture negative, slowly progressive graft infection in a patient with a draining left groin mass 1 year after placement of an aortobifemoral graft for peripheral vascular disease. Angiography demonstrated no pseudoaneurysm. (a) CT scan obtained March 23, 1987, shows perigraft soft-tissue attenuation extending to the skin (arrowhead). (b) CT scan obtained May 13, 1988 (one of a number of follow-up CT scans), shows a small perigraft fluid collection and enhancing soft-tissue attenuation around the graft (arrowhead), findings consistent with perigraft infection. Fluid aspiration was positive for WBCs, but the culture was negative. In July 1989, the left limb of the graft was removed because it was infected and unresponsive to conservative therapy. In August 1989, the patient was readmitted for elective left axillofemoral bypass. (c) Follow-up CT scan obtained November 14, 1989, shows a fluid collection around the axillofemoral graft, which was positive for WBCs but negative at culture. (d) CT scan obtained December 17, 1989, shows persistence of the fluid collection and extension to the left groin (arrowhead). (e) CT scan obtained August 13, 1991, shows fluid around the right limb of the aortic bifurcation graft (arrow). This finding prompted excision of the entire aortic graft and placement of a right axillofemoral graft. (f) CT scan obtained October 4, 1991, shows persistent fluid around the left axillofemoral graft (arrow), but the graft remained uninfected. Subsequently, the left axillofemoral graft was removed and a femoral-femoral graft was placed. The infection was presumed to be due to S epidermidis on the basis of the clinical course and the multiple negative cultures, which are characteristic of slime-producing organisms such as S epidermidis.

View larger version (122K): [in a new window]   Figure 8e.   Persistently culture negative, slowly progressive graft infection in a patient with a draining left groin mass 1 year after placement of an aortobifemoral graft for peripheral vascular disease. Angiography demonstrated no pseudoaneurysm. (a) CT scan obtained March 23, 1987, shows perigraft soft-tissue attenuation extending to the skin (arrowhead). (b) CT scan obtained May 13, 1988 (one of a number of follow-up CT scans), shows a small perigraft fluid collection and enhancing soft-tissue attenuation around the graft (arrowhead), findings consistent with perigraft infection. Fluid aspiration was positive for WBCs, but the culture was negative. In July 1989, the left limb of the graft was removed because it was infected and unresponsive to conservative therapy. In August 1989, the patient was readmitted for elective left axillofemoral bypass. (c) Follow-up CT scan obtained November 14, 1989, shows a fluid collection around the axillofemoral graft, which was positive for WBCs but negative at culture. (d) CT scan obtained December 17, 1989, shows persistence of the fluid collection and extension to the left groin (arrowhead). (e) CT scan obtained August 13, 1991, shows fluid around the right limb of the aortic bifurcation graft (arrow). This finding prompted excision of the entire aortic graft and placement of a right axillofemoral graft. (f) CT scan obtained October 4, 1991, shows persistent fluid around the left axillofemoral graft (arrow), but the graft remained uninfected. Subsequently, the left axillofemoral graft was removed and a femoral-femoral graft was placed. The infection was presumed to be due to S epidermidis on the basis of the clinical course and the multiple negative cultures, which are characteristic of slime-producing organisms such as S epidermidis.

View larger version (111K): [in a new window]   Figure 8f.   Persistently culture negative, slowly progressive graft infection in a patient with a draining left groin mass 1 year after placement of an aortobifemoral graft for peripheral vascular disease. Angiography demonstrated no pseudoaneurysm. (a) CT scan obtained March 23, 1987, shows perigraft soft-tissue attenuation extending to the skin (arrowhead). (b) CT scan obtained May 13, 1988 (one of a number of follow-up CT scans), shows a small perigraft fluid collection and enhancing soft-tissue attenuation around the graft (arrowhead), findings consistent with perigraft infection. Fluid aspiration was positive for WBCs, but the culture was negative. In July 1989, the left limb of the graft was removed because it was infected and unresponsive to conservative therapy. In August 1989, the patient was readmitted for elective left axillofemoral bypass. (c) Follow-up CT scan obtained November 14, 1989, shows a fluid collection around the axillofemoral graft, which was positive for WBCs but negative at culture. (d) CT scan obtained December 17, 1989, shows persistence of the fluid collection and extension to the left groin (arrowhead). (e) CT scan obtained August 13, 1991, shows fluid around the right limb of the aortic bifurcation graft (arrow). This finding prompted excision of the entire aortic graft and placement of a right axillofemoral graft. (f) CT scan obtained October 4, 1991, shows persistent fluid around the left axillofemoral graft (arrow), but the graft remained uninfected. Subsequently, the left axillofemoral graft was removed and a femoral-femoral graft was placed. The infection was presumed to be due to S epidermidis on the basis of the clinical course and the multiple negative cultures, which are characteristic of slime-producing organisms such as S epidermidis.

View larger version (121K): [in a new window]   Figure 9a.   Graft infection in a patient with an aortic bifurcation graft. (a) CT scan obtained several years after graft placement shows that the wall of the right limb of the graft is indistinct (straight arrow), merging with an area of soft-tissue attenuation and without a circular rim of fat. This appearance was not recognized at the time as a very suspicious finding for graft infection. A fluid-filled loop of ileum is present anterior to the right psoas muscle (curved arrow). The abnormality was not recognized until development of an obvious graft infection and psoas abscess 1 year later. (b) CT scan obtained approximately 1 year later shows a right psoas abscess in the same location, contiguous with the graft (arrow) (window width and level were changed to show the abscess better). At surgery, there was staining of the graft in this location, indicating an enteric fistula.

View larger version (106K): [in a new window]   Figure 9b.   Graft infection in a patient with an aortic bifurcation graft. (a) CT scan obtained several years after graft placement shows that the wall of the right limb of the graft is indistinct (straight arrow), merging with an area of soft-tissue attenuation and without a circular rim of fat. This appearance was not recognized at the time as a very suspicious finding for graft infection. A fluid-filled loop of ileum is present anterior to the right psoas muscle (curved arrow). The abnormality was not recognized until development of an obvious graft infection and psoas abscess 1 year later. (b) CT scan obtained approximately 1 year later shows a right psoas abscess in the same location, contiguous with the graft (arrow) (window width and level were changed to show the abscess better). At surgery, there was staining of the graft in this location, indicating an enteric fistula.

View larger version (131K): [in a new window]   Figure 10a.   Psoas abscess in a symptomatic patient with a horseshoe kidney and an abdominal aortic aneurysm. (a) CT scan shows the early postoperative appearance. (b) CT scan shows that the left portion of the horseshoe kidney has become infarcted, with eventual gas in the graft (not shown) and concomitant abscess formation. The left psoas abscess (arrow) is contiguous with the graft; thus, the graft was removed.

View larger version (122K): [in a new window]   Figure 10b.   Psoas abscess in a symptomatic patient with a horseshoe kidney and an abdominal aortic aneurysm. (a) CT scan shows the early postoperative appearance. (b) CT scan shows that the left portion of the horseshoe kidney has become infarcted, with eventual gas in the graft (not shown) and concomitant abscess formation. The left psoas abscess (arrow) is contiguous with the graft; thus, the graft was removed.

View larger version (122K): [in a new window]   Figure 11.   Perigraft fluid collection. CT scan obtained about 5 months after surgery shows soft-tissue attenuation extending to the skin and the femoral component of the left limb of the graft. CT showed no proximal extension. The patient was successfully treated with intravenous antibiotics.

View larger version (141K): [in a new window]   Figure 12a.   Pseudoaneurysm. (a) Angiogram shows a left-sided pseudoaneurysm. (b) CT scan shows lower-attenuation perigraft fluid (arrow). The patient subsequently underwent pseudoaneurysm repair and creation of an extraanatomic bypass, which also became infected.

View larger version (119K): [in a new window]   Figure 12b.   Pseudoaneurysm. (a) Angiogram shows a left-sided pseudoaneurysm. (b) CT scan shows lower-attenuation perigraft fluid (arrow). The patient subsequently underwent pseudoaneurysm repair and creation of an extraanatomic bypass, which also became infected.

View larger version (131K): [in a new window]   Figure 13.   Aortic stump blowout in a patient with back pain and a drop in hematocrit level 6 months after aortic graft removal. CT scan shows a pool of contrast material extending from the aortic stump (arrow), with temporary tamponade of the collection by the left psoas muscle.

View larger version (131K): [in a new window]   Figure 14.   Aortic stump blowout. CT scan obtained 3 months after prior repair of an aortic stump blowout shows blood attenuation extending from the aortic stump (arrows).

View larger version (98K): [in a new window]   Figure 15a.   Pseudoaneurysm in a 61-year-old hypertensive patient with bilateral thoracic-aortic-femoral and axillary-profunda femoral bypass grafts. The patient developed a fistula from the graft to the left lower lobe of the lung, which was resected with muscle flap closure. Several weeks later, the patient developed hemoptysis and presented to the local emergency department. (a) CT scan of the lower chest shows the end-to-side anastomosis with a pseudoaneurysm on the left side (arrow). The pseudoaneurysm is partly occluded, but there is also some leakage with resultant loculated left lower lobe hemothorax. (b) Aortogram obtained with a brachial approach on the same day shows an irregular outpocketing of contrast material arising from the end-to-side anastomosis at approximately the level of T10, with some leakage into the left hemithorax (arrows). Immediate surgery was performed, which consisted of Dacron graft repair of the recurrent pseudoaneurysm with left lower lobe resection, as well as resection of the prior muscle flap closure in the left chest wall. Intraoperative cultures demonstrated infection with Candida. The postoperative course was otherwise uneventful with long-term antibiotic coverage. The final culture result was Candida parapsilosis of the anastomosis. (Courtesy of James Caridi, MD, Shands Hospital, Gainesville, Fla.)

View larger version (114K): [in a new window]   Figure 15b.   Pseudoaneurysm in a 61-year-old hypertensive patient with bilateral thoracic-aortic-femoral and axillary-profunda femoral bypass grafts. The patient developed a fistula from the graft to the left lower lobe of the lung, which was resected with muscle flap closure. Several weeks later, the patient developed hemoptysis and presented to the local emergency department. (a) CT scan of the lower chest shows the end-to-side anastomosis with a pseudoaneurysm on the left side (arrow). The pseudoaneurysm is partly occluded, but there is also some leakage with resultant loculated left lower lobe hemothorax. (b) Aortogram obtained with a brachial approach on the same day shows an irregular outpocketing of contrast material arising from the end-to-side anastomosis at approximately the level of T10, with some leakage into the left hemithorax (arrows). Immediate surgery was performed, which consisted of Dacron graft repair of the recurrent pseudoaneurysm with left lower lobe resection, as well as resection of the prior muscle flap closure in the left chest wall. Intraoperative cultures demonstrated infection with Candida. The postoperative course was otherwise uneventful with long-term antibiotic coverage. The final culture result was Candida parapsilosis of the anastomosis. (Courtesy of James Caridi, MD, Shands Hospital, Gainesville, Fla.)

View larger version (128K): [in a new window]   Figure 16a.   Pseudoaneurysm. (a) CT scan shows a dumbbell-shaped fluid collection (arrows) immediately below the aortic stump (not shown), as well as signs of peritonitis. (b) Radiograph obtained after placement of a temporizing abscess drainage catheter shows a small-bowel communication, which was thought to be a forme fruste of aortoenteric fistula.

View larger version (104K): [in a new window]   Figure 16b.   Pseudoaneurysm. (a) CT scan shows a dumbbell-shaped fluid collection (arrows) immediately below the aortic stump (not shown), as well as signs of peritonitis. (b) Radiograph obtained after placement of a temporizing abscess drainage catheter shows a small-bowel communication, which was thought to be a forme fruste of aortoenteric fistula.

View larger version (119K): [in a new window]   Figure 17.   Pseudoaneurysm. Radiograph obtained after placement of a temporizing abscess drainage catheter shows a colon communication, which was thought to be a forme fruste of aortoenteric fistula.

View larger version (121K): [in a new window]   Figure 18a.   Perigraft malignancy. (a) CT scan shows a likely graft abscess in the left groin, with apparent extensive fluid around the graft at the anastomosis. (b) Longitudinal US scan shows a mass that is echoic and probably solid (arrow), thus raising the possibility of a malignancy rather than an infection. US-guided needle aspiration demonstrated an unusual case of metastatic squamous cell carcinoma surrounding the graft.

View larger version (74K): [in a new window]   Figure 18b.   Perigraft malignancy. (a) CT scan shows a likely graft abscess in the left groin, with apparent extensive fluid around the graft at the anastomosis. (b) Longitudinal US scan shows a mass that is echoic and probably solid (arrow), thus raising the possibility of a malignancy rather than an infection. US-guided needle aspiration demonstrated an unusual case of metastatic squamous cell carcinoma surrounding the graft.

View larger version (152K): [in a new window]   Figure 19.   Graft infection. In-111-labeled WBC scan shows uptake in the right groin and to a lesser extent along the right iliac limb of the bifurcation graft (arrow). (Courtesy of Gary Purnell, MD, University of Arkansas, Little Rock.)

View larger version (112K): [in a new window]   Figure 20.   Graft infection. In-111-labeled WBC scan shows uptake in the distal portion of a left femoral-popliteal bypass graft (arrow). (Courtesy of Gary Purnell, MD, University of Arkansas, Little Rock.)

View larger version (91K): [in a new window]   Figure 21a.   Graft infection. (a) CT scan shows an infected right obturator bypass graft (arrow) with fluid around it and further distally in the thigh. (b) Sinogram shows the extent of the infection, with contrast material tracking all the way to the obturator foramen.

View larger version (49K): [in a new window]   Figure 21b.   Graft infection. (a) CT scan shows an infected right obturator bypass graft (arrow) with fluid around it and further distally in the thigh. (b) Sinogram shows the extent of the infection, with contrast material tracking all the way to the obturator foramen.

View larger version (144K): [in a new window]   Figure 22a.   Groin abscess. (a) US scan shows a fluid collection (arrow) adjacent to the femoral limb of an aortic bifurcation graft, suggesting possible graft infection. (b) Sinogram shows that contrast material does not track along the graft, indicating that infection does not involve the graft or is very focal.

View larger version (112K): [in a new window]   Figure 22b.   Groin abscess. (a) US scan shows a fluid collection (arrow) adjacent to the femoral limb of an aortic bifurcation graft, suggesting possible graft infection. (b) Sinogram shows that contrast material does not track along the graft, indicating that infection does not involve the graft or is very focal.

View larger version (120K): [in a new window]   Figure 23a.   Hydronephrosis secondary to ureteral entrapment. (a) CT scan shows marked right hydronephrosis. (b) CT scan shows entrapment of the right ureter between the right limb of an aortic bifurcation graft and the right native iliac artery. The margins of the right limb of the graft are indistinct and not surrounded by fat (arrow), unlike on the contralateral side. (c) Nephrostogram shows the same level of obstruction seen in b. The early indistinctness of the graft wall and the significance of the hydronephrosis were not recognized as foretelling a graft infection, which became clinically apparent 1 year later.

View larger version (118K): [in a new window]   Figure 23b.   Hydronephrosis secondary to ureteral entrapment. (a) CT scan shows marked right hydronephrosis. (b) CT scan shows entrapment of the right ureter between the right limb of an aortic bifurcation graft and the right native iliac artery. The margins of the right limb of the graft are indistinct and not surrounded by fat (arrow), unlike on the contralateral side. (c) Nephrostogram shows the same level of obstruction seen in b. The early indistinctness of the graft wall and the significance of the hydronephrosis were not recognized as foretelling a graft infection, which became clinically apparent 1 year later.

View larger version (134K): [in a new window]   Figure 23c.   Hydronephrosis secondary to ureteral entrapment. (a) CT scan shows marked right hydronephrosis. (b) CT scan shows entrapment of the right ureter between the right limb of an aortic bifurcation graft and the right native iliac artery. The margins of the right limb of the graft are indistinct and not surrounded by fat (arrow), unlike on the contralateral side. (c) Nephrostogram shows the same level of obstruction seen in b. The early indistinctness of the graft wall and the significance of the hydronephrosis were not recognized as foretelling a graft infection, which became clinically apparent 1 year later.

View larger version (143K): [in a new window]   Figure 24a.   Hydronephrosis secondary to ureteral entrapment. Two CT scans from a series show a large amount of fluid tracking down the right limb of an aortic graft (curved arrow in b) and causing obstruction of the right kidney secondary to mass effect by the fluid. The fluid was eventually positive at culture. The lower image may also show a large urinoma (straight arrow in b) with marked ureteral dilatation.

View larger version (138K): [in a new window]   Figure 24b.   Hydronephrosis secondary to ureteral entrapment. Two CT scans from a series show a large amount of fluid tracking down the right limb of an aortic graft (curved arrow in b) and causing obstruction of the right kidney secondary to mass effect by the fluid. The fluid was eventually positive at culture. The lower image may also show a large urinoma (straight arrow in b) with marked ureteral dilatation.

View larger version (107K): [in a new window]   Figure 25a.   Osteomyelitis secondary to graft infection. (a) Pelvic radiograph shows bilateral lytic lesions (arrowheads), which were initially thought to be metastatic. (b) CT scan shows a lytic lesion in the right lesser trochanter (arrow), which corresponds to an infection of the right psoas muscle and a fluid collection along the right limb of the aortofemoral graft (not shown). CT-guided bone biopsy performed at this level showed that the lesion was osteomyelitis. The infection probably tracked along the psoas muscle into its insertion on the femur.

View larger version (104K): [in a new window]   Figure 25b.   Osteomyelitis secondary to graft infection. (a) Pelvic radiograph shows bilateral lytic lesions (arrowheads), which were initially thought to be metastatic. (b) CT scan shows a lytic lesion in the right lesser trochanter (arrow), which corresponds to an infection of the right psoas muscle and a fluid collection along the right limb of the aortofemoral graft (not shown). CT-guided bone biopsy performed at this level showed that the lesion was osteomyelitis. The infection probably tracked along the psoas muscle into its insertion on the femur.

View larger version (35K): [in a new window]   Figure 26.   Algorithm for the work-up of various complications of graft infection. The algorithm is used in cases with a high clinical index of suspicion based on physical examination results, history, or laboratory values (viz, elevated WBC count and sedimentation rate). IVP = intravenous pyelography.