Inflammatory aortic aneurysm - longitudinal imaging

Case contributed by Ian Bickle
Diagnosis certain

Presentation

Abdominal pain and raised ESR.

Patient Data

Age: 75 years
Gender: Female

4.6 cm infrarenal abdominal aortic aneurysm with aortic wall thickening, exerting mass effect on the pancreatic head/IVC. Periaortic fat stranding. Minimal fluid in the presacral space.

Normal origin and opacification of the celiac, superior mesenteric and renal arteries.

Couple of tiny cysts in the left hepatic lobe. 

Trace of pleural fluid.

4.7 cm infrarenal abdominal aortic aneurysm. The aneurysm is unchanged in size compared with the CT performed one week earlier. Cuff of periaortic soft tissue anteriorly and laterally on the right side. Stranding of the left periaortic fat. No free fluid.

The right kidney is supplied by 2 small caliber arteries arising anteriorly from the aorta, the larger one supplying the upper and mid pole.

Normal origin of the left renal artery. The IMA arises from within the aneurysm sac.

The SMA passes to the left of the midline (not the usual midline position) with the head and neck of the pancreas displaced to the left draped over the anterior aspect of the aneurysm.

8 mm cyst in the body of the pancreas. The solid organs of the upper abdomen are otherwise normal in appearance.

The free fluid in the pelvis on the previous study has resolved.

Emphysematous changes in the lungs. Minor atelectasis. 

Comment: Static aneurysm in size. I am highly concerned that this represents an inflammatory aneurysm.

 

When compared with the previous scan there has been a significant increase in the size of the infrarenal abdominal aortic aneurysm now measuring up to 6.1 cm in maximum AP diameter, previously 4.7 cm.  It is now more saccular in nature.

The rapid increase in size of the aneurysm is suggestive of an infected inflammatory/mycotic aneurysm and urgent vascular referral is advised.

17 days later. Intervening...

ct

17 days later. Intervening surgery

Endovascular repair of infra-renal abdominal aortic aneurysm.

Supra renal abdominal aorta, both renal arteries, celiac trunk, superior and inferior mesenteric artery and all their major branches outline normally with contrast. 

The lumen of endovascular repaired infrarenal abdominal aorta adequately enhances. Focal blush of contrast posterior to the right limb of the abdominal aortic stent before it extends into the right iliac vessels (at L3/L4 level ) in keeping with an endoleak in the aneurysmal sac. This blush is not apparent on the non contrast study.

Stable appearing abdominal aortic aneurysm approximately measures 6.0 cm in AP diameter.  The walls of the aneurysm are still thickened in keeping with the known inflammatory aneurysm.

Both common iliac, internal and external iliac arteries outline normally with contrast.

Hepatic cyst. Stable appearing well-defined cyst in the pancreatic head.

Both adrenals, kidneys, gallbladder outline normally with contrast.

No intestinal obstruction/pneumoperitoneum. Moderate volume free fluid in the pelvis.

Background centrilobular emphysema. Bilateral mild pleural effusions with atelectatic bands at both lung bases. Main airways are clear. No pericardial effusion.

Ill-defined peripheral ground glass patchy opacification is noted in the right lower and middle lobe.  Multi-level, multi-station, small volume mediastinal lymph nodes.

No suspicious osseous lesion noted in the visualized skeleton.

Comment: Type II endoleak posteriorly in the sac just above the bifurcation.

Case Discussion

The initial CT was undertaken for abdominal pain on which aneurysm was identified.

The thick walled aneurysm enlarged rapidly consistent with an inflammatory aneurysm, especially in the context of a raised ESR.

The aneurysm was repaired, after which a type II endoleak occurred.

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