感染性動脈瘤の下記文献の所見の中で，腹部大動脈と右総腸骨動脈右側に8ヶ月前には存在しなかった異常な軟部組織がある（▲），嚢状（saccular）である（血管の走行に蛇行はなく，右側に突出した軟部組織である），図５〜図９で周囲の浮腫（↑）があり，さらに図７と図８の△は動脈内腔とつながる造影剤と思われ，感染性動脈瘤と診断する．A：腹部大動脈，CIA：総腸骨動脈，IVC：下大静脈．CT診断により緊急手術を施行した．右総腸骨動脈と下部大動脈周囲に血腫が形成されており，血腫を除去すると右総腸骨動脈と下部大動脈にかけて破綻部が認められ周囲の壁は変色していた．感染部を切除し，左腋窩動脈・両大腿動脈バイパスを行った．切除した動脈壁から黄色ブドウ球菌が培養された．7ヶ月後に解剖学的経路のYgraft置換術を施行した．

文献梗塞：感染性腹部動脈瘤
Radiology. 2004 Apr;231(1):250-7.
Infected aortic aneurysms: imaging findings.
Macedo TA, Stanson AW, Oderich GS, Johnson CM, Panneton JM, Tie ML.

PURPOSE: To determine the imaging characteristics of infected aortic aneurysms. MATERIALS AND METHODS: Review of records of patients with surgical and/or microbiologic proof of infected aortic aneurysm obtained over a 25-year period revealed 31 aneurysms in 29 patients. This study included 21 men and eight women (mean age, 70 years). One radiologist reviewed 28 computed tomographic (CT) studies (22 patients underwent CT once and three patients underwent CT twice), 12 arteriograms (12 patients underwent arteriography once), eight nuclear medicine studies (six patients underwent nuclear medicine imaging once and one patient underwent nuclear medicine imaging twice), and three magnetic resonance (MR) studies (three patients underwent MR imaging once). Features evaluated included aneurysm size, shape, and location; branch involvement; aortic wall calcification; gas; radiotracer uptake on nuclear medicine studies; and periaortic and associated findings. The location of infected aortic aneurysms was compared with that of arteriosclerotic aneurysms. RESULTS: Aneurysms were located in the ascending aorta (n = 2, 6%), descending thoracic aorta (n = 7, 23%), thoracoabdominal aorta (n = 6, 19%), paravisceral aorta (n = 2, 6%), juxtarenal aorta (n = 3, 10%), infrarenal aorta (n = 10, 32%), and renal artery (n = 1, 3%). Two patients had two infected aortic aneurysms. CT revealed 25 saccular (93%) and two fusiform (7%) aneurysms with a mean diameter at initial discovery of 5.4 cm (range, 1-11 cm). Paraaortic soft-tissue mass, stranding, and/or fluid was present in 13 (48%) of 27 aneurysms, and early periaortic edema with rapid aneurysm progression and development was present in three (100%) patients with sequential studies. Other findings included adjacent vertebral body destruction with psoas muscle abscess (n = 1, 4%), kidney infarct (n = 1, 4%), absence of calcification in the aortic wall (n = 2, 7%), and periaortic gas (n = 2, 7%). Angiography showed 13 saccular aneurysms with lobulated contour in 10 (77%). Nuclear medicine imaging showed increased activity consistent with infection in six (86%) of seven aneurysms. MR imaging showed three saccular aneurysms. Adjacent abnormal vertebral body marrow signal intensity was seen in one (33%) of three patients. CONCLUSION: Saccular aneurysms (especially those with lobulated contour) with rapid expansion or development and adjacent mass, stranding, and/or fluid in an unusual location are highly suspicious for an infected aneurysm. PMID: 15068950
追記：全動脈瘤の0.7-2.6%，診断治療共に困難で，破裂しやすい（53-75％が破裂してから手術されている），死亡率は16-67％と高い．