A 13-year-old boy presented with abdominal pain and vomiting due to pancreatitis. Ultrasound revealed a pseudoaneurysm sac in the pancreas but failed to identify the arterial feeder. CT angiography and digital subtraction angiography also could not identify the feeder artery. Therefore, embolization materials were directly injected into the pseudoaneurysm sac under ultrasound guidance, resulting in complete thrombosis and resolution of symptoms. This case report describes an alternative percutaneous approach for embolizing a pseudoaneurysm when conventional angiography fails to identify the feeding artery.

1. A rare case of percutaneous therapeutic embolization of
pancreatitis induced pseudoaneurysm evading identification on
conventional CT angiography and digital subtraction angiography
Dr. Gaurang Pandey (Junior Resident-2)
Department of Radiodiagnosis, KGMU, Lucknow

2. ABSTRACT
A pancreatic pseudoaneurysm is a rare vascular complication of pancreatitis with a
reported incidence of less than 10% [1], resulting from the erosion of branches of
splenic artery, gastroduodenal artery or superior mesenteric artery (SMA) [2]. If
pseudocysts are present, the rate rises to 20%. In untreated patients of arterial
complications of pancreatitis, the mortality rate is 90%, but in treated patients it
ranges from 15% to 50%. [3] . Hence, early recognition and intervention is
necessitated as fatal hemorrhage may result.
We report a rare case of an adolescent male that presented with abdominal pain
and vomiting for 1 month and elevated serum amylase and lipase enzymes.
Diagnosis of Pancreatitis induced pseudoaneurysm (PSA) was made on
ultrasonography. However, both color doppler interrogation and Computed
tomography (CT) angiography failed to demonstrate any definite offending artery.
Further ahead, the PSA sac evaded any opacification on Digital subtraction
angiography (DSA) and thus conventional endovascular/transarterial
embolotherapy could not attempted . Ultrasound guided percutaneous injection
of embolizing agents into the PSA sac was hence resorted to with resultant
complete thrombosis and an unventful postoperative follow-up achieved.
Figure 1- Heterogenous pancreas with
peripancreatic collection and a well
defined hypoechoic lesion exhibiting
ying-yang sign on colour doppler is
noted epicentered in the peripancreatic
collection -Pancreatitis induced
partially thrombosed pseudoaneurysm
(PSA). However no definite arterial
feeder is seen.

3. CASE REPORT
A 13 year old boy presented with moderate abdominal pain and vomiting for 1 month. Biochemical
profile revealed elevated serum amylase and lipase. On ultrasound evaluation, heterogenous bulky
pancreas with approx 200 ml of peripancreatic collection was noted. A well defined anechoic
pseudoaneurysm (PSA) sac measuring 23x17 mm, exhibiting ying-yang sign of vascularity and to-and-
fro spectral pattern on color doppler was noted epicentered within the peripancreatic collection in the
stomach bed region. Diagnosis of pancreatitis induced pseudoaneurysm (PSA) was made .However no
definite communication of the PSA sac with any branch of celiac trunk or SMA could be established. CT
angiography was conducted which failed to demonstrate any definite vascular feeder or signs of
arterial injury. Digital subtraction angiography (DSA) assissted embolization was hence planned
wherein superselective angiograms of all the branches of celiac trunk and SMA were taken but no
opacification of the PSA sac was seen.
A alternative approach was hence resorted to in which embolic agents (1:1 v/v mixture of N-butyl
cynoacrylate glue and ethiodized poppy oil - Lipidol) were percutaneously injected into ithe PSA sac
under ultrasound guidance using 20-G lumbar puncture needle and complete thrombosis was achieved
as evinced by absence of any intralesional vascularity on color doppler. No procedure related
complications or fresh complaints were noted on follow-up.

4. Figure 4- Post percutaneous-
embolization doppler US image
showing no intralesional
vascularity suggestive of
complete thrombosis
Figure 2 - Selective angiogram of
celiac trunk and its branches fail to
demonstrate any pseudoaneurysmal
sac or offending arterial feeder
Figure 3 – Opacification of the
pseudoaneurysm sac following USG
guided percutaneous injection of the
embolizing agents

5. DISCUSSION
A pseudoaneurysm is a localized arterial disruption of the intimal and medial layers, lined by adventitia or
perivascular tissue, resulting from trauma, iatrogenic causes and inflammatory conditions like Pancreatitis where
there is autodigestion of the arterial wall by pancreatic enzymes.
Doppler ultrasonography helps establish the diagnosis wherein a PSA sac appears as an anechoic cystic lesion
demonstrating “yin- yang” vascularity and “to-and-fro” waveform with a communicating neck seen between the
sac and the feeding artery. CT angiography demonstrates a contrast filled low-attenuation rounded structure arising
from the donor artery. Adjacent spillage denotes rupture whereas partial contrast filling indicates thrombosis.
Digital subtraction angiography remains the gold standard for the diagnosis of PSA, offering the advantage of real-
time hemodynamic assessment and accurate identification of the donor artery [4].
Management comprises surgical, endovascular and percutaneous approaches. Endovascular approach is currently
the preferred modality with high reported success rates. The principle includes packing the lumen of the aneurysm
with embolizing agents, or excluding the neck (the “sandwich” method) with proximal and distal coil embolization.
Detachable balloons, stents, inert particles or resorbable gelatin (Gelfoam) are also used.
Percutaneous techniques have been used with increasing frequency as an alternative to endovascular treatment.
Under ultrasound guidance, a 20- or 22-gauge needle is introduced into the pseudoaneurysm and
thrombin/embolic agents are injected until there is cessation of flow. High success rates, low complication rates,
ease of performance, short procedure times, and no radiation exposure—favor the use of US-guided percutaneous
approach as the treatment of choice for treating pseudoaneurysms [5].

6. CONCLUSION
A percutaneous approach to pseudoaneurysm embolization can hence be considered a promising
alternative to conventional endovascular/transarterial technique which may fail to reveal an offending
arterial feeder under such rare circumstances.
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