| Abstract|| |
Pseudoaneurysm can arise due to various etiologies and patient may presents with symptoms not related with primary location of lesion. This article describes an unusual case of pseudoaneurysm diagnosed on USG. Old aged female patient presented with episodes of altered consciousness. USG study of abdomen revealed huge multilayered lesion in left hypochondrial region with peripheral anechoic region, which showed continuous and regular pulsation on real time study. We put diagnosis of pseudoaneurysm of splenic artery. The patient was advised for CT scan and findings were confirmed. Awareness of typical sonographic appearance of pseudoaneurysm may aid in early and proper diagnosis.
Keywords: Pseudoaneurysm, Splenic Artery, USG, CT Scan, MIP (Maximum Intensity Projection)
|How to cite this article:|
Soni H C, Patel S B, Goswami K G. Case report: Pseudoaneurysm of splenic artery. Indian J Radiol Imaging 2006;16:509-11
| Introduction|| |
Splenic vessel pseudoaneurysm is uncommon condition develops following some sort of trauma to vessel wall. Lesion consists of single cavity continuous with lumen of vessel covered by meniscus shaped thrombus1. These rather uncommon pseudoaneurysms are frequently accompanied by life-threatening complications, mainly rupture and bleeding. Better outcome requires accurate, timely, and appropriate diagnosis and medical and/or surgical intervention.
| Case History|| |
50 years old female patient presented with complain of three episode of altered consciousness in last month. There is history of abdominal trauma before two years and complain of discomfort in abdomen since then. Patient had no history of hematemesis, melena, or high grade fever. Patient was initially advised for USG Abdomen. USG examination was performed with 3.5MHz convex & 6.5 MHz sector probes on 'RT 3200 Advantage II' machine. USG revealed a huge, well defined multilayered lesion [Figure - 1] with peripheral anechoic area [Figure - 2] in left hypochondrial region. Peripheral anechoic region appears to be continuous with splenic artery and real time USG showd continuous and regular pulsation. Pancreas, spleen, kidneys, perinephric space and liver were normal. We put the diagnosis of pseudoaneurysm from splenic artery, which may be due to trauma itself or episode of acute pancreatitis following trauma. Patient was advised CT Scan examination. NCCT showed huge hypodense lesion anteromedial to spleen with peripheral calcification [Figure - 3]. CECT showed the lesion posterior to splenic artery with enhancing lumen of pseudoaneurysm, which is continuous with main lumen of splenic artery [Figure - 4]. Whole lesion is demonstrated on MIP [Figure - 5].
| Discussion|| |
Splenic artery aneurysms are the most frequent visceral artery aneurysm accounting for as many as 60% of all the splanchnic artery aneurysms. The common etiologies include pancreatitis, trauma, congenital, mycotic, fibromuscular dysplasia, medial degeneration with superimposed atherosclerosis and after resection of biliopancreatic cancer.
Patient usually presents with episode of abdominal pain or trauma followed by gradually enlarging lesion in upper abdomen and pain. Intermittent embolism from clot can lead to ischemic symptoms in affected organ. Acute massive haemorrhage can lead to shock.
Acute Pancreatitis is one of the most common cause of pseudoaeurysm and Splenic artery is involved most frequently (30-50%) followed by gastroduodenal artery (10-15%) & pancreaticoduodenal arteries (10%), followed by left gastric, hepatic and small intrapancreatic arteries.
The pathogenesis of aneurysm following pancreatitis is:
(a) enzyme rich peripancreatic fluid often within a pseudocyst, which leads to auto-digestion & weakening of the walls of adjacent arteries.
(b) rupture of aneurysm into pseudocyst converts it into a pseudoaneurysm.
(c) these peripancreatic arteries undergo aneurysmal dilatation with the aneurysmal bulge most often contained in pseudocyst.
Posttraumatic pseudoaneurysm is not uncommon3. Trauma itself can cause injury to splenic artery and can lead to pseudoaneurysm or more commonly episode of subclinical/ clinical acute pancreatitis can lead to injury to wall of vessel leading to pseudoaneurysm.
Sonography is usually initial investigation modality used for diagnosis because of wide availability, cheap and gives excellent information especially for abdomen and pelvic pathologies. The only disadvantage with USG is operator dependency. The sonographic appearance of pseudoaneurysm varies depending on size of lesion, presence and extent of patency of lumen, which is continuous with vessel, size of thrombus, presence of haemorrhage and degree of calcification. On USG pseudoaneurysm typically appears as multilayered lesion with central or peripheral anechoic lesion, which is continuous with arterial lumen. As the central or peripheral anechoic area is continuous with arterial lumen, it shows continuous arterial pulsation on real time ultrasonography, which is highly suggestive of pseudoaneurysm4. This was the sonographic appearance of our patient. Some times arterial pulsation is not visualized in anechoic area. It is especially in case when pseudoaneurysm arising from small artery or when only small portion of lesion is patent and continuous with arterial lumen. In such cases moving echoes within the lesion with high frequency ultrasound probe is suggestive of arterial continuation of lesion. In our case, pseudoaneurysm arises from splenic artery. Other possible size of origin includes gastro-duodenal artery and short gastric artery.
CT Scan is very helpful not only in confirming the diagnosis of lesion, but it also demonstrates continuation of pseudoaneurysm with parent vessel, can detect extent of thrombus component of lesion, size and extent of lesion, presence of haemorrhage and status of distal and other organ. On NCCT pseudoaneurysm appears as hypodense lesion or multilayered lesion. Acute haemorrhage is demonstrated by hyperdense area. CECT shows contrast enhancement of patent portion of lesion, which is continuous with parent artery. It also differentiates between thrombus and arterial wall. Multiplanner reconstruction of MIP images of CECT images can give 3D image of whole lesion. It is useful in better communication with surgeon.
The anechoic lumen of aneurysm shows colour on colour box, and special characterized waveform pattern can be detected at neck of pseudoaneurysm4. If the patient is hemodynamically stable, performing a preoperative angiogram helps confirm the diagnosis. Angiography defines the character-unique or otherwise-of the lesion and allows therapeutic planning. Preoperative angiography might constitute an opportunity to gain temporary control over the bleeding vessel by performing transcatheter embolization, thus providing a time window for the surgeon to operate on a high-risk patient under optimum clinical conditions. MRI has its own added advantages over CT Scan of Multiplanner capacity, inherent soft tissue contrast, lake of radiation and angiography like image reconstruction. Preoperative angiography helps confirming diagnosis, defines character, anatomy and allows therapeutic planning.
| References|| |
|1.||Arnold Friedman. Radiology of the liver, biliary tract, pancreas and spleen. 1987:674 |
|2.||Burke WJ, Ericson JS, Kellum DC et al: Pseudoaneurysm complicating pancreatitis: Detection by ct. radiology 1986; 161:447-50. |
|3.||Splenic Artery Pseudoaneurysm Associated With Blunt Abdominal Trauma. R Malik, VK Pandya, D Naik, Ind J Radiol Imag 2003 13:4:399- 400 |
|4.||Falkoff GE, Taylor KJW, Morse S. Hepatic artery pseudoaneurysm: diagnosis with real time and pulsed Doppler US. Radiology 1986; 158: 55-56. |
|5.||McDermott VG, Schlansky-Goldberg R, Cope C, Endovascular management of splenic artery aneurysms and pseudoaneurysms. Cardiovasc-Int-Radilogy 1994; 17:179-184. |
H C Soni
Department of Radio-diagnosis, Gujarat Cancer & Research Institute, Asarwa, Ahmedabad - 380016 Gujarat State
Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]