Radiology

Case 26: Contributed by Dr Krantikumar Rathod

Other Cases

Fig. 1 A	Fig. 1 B

There was also mild dilatation of intrahepatic billiary radicals (IHBR) in the left lobe of the liver adjacent to the aneurysm. Contrast enhanced computed tomography of the abdomen revealed an enhancing lesion in arterial phase, with surrounding focal dilatation of IHBR in left lobe of liver (Fig.2).

Fig. 2

Fig. 3

The left hepatic artery was selectively catheterized with a 5F Cobra Catheter (Cordis) and a microcatheter system (Mass TRANSIT 3/2.8 F -Cordis, Johnson & Johnson). However, the microcatheter could not be negotiated superselectively into the intrahepatic branch on which the pseudoaneurysm was located; hence, embolisation by transcatheter approach was deferred and a decision to occlude the aneurysm percutaneously under ultrasound guidance was taken. A 19 G Chiba needle (Angiomed, BARD) was introduced under local anesthesia under ultrasound guidance (ATL, HDI 3000) without needle guidance system to enter into the aneurysm (Fig.4).

Fig. 4

The position of the needle tip was confirmed by checking backflow of blood and mobile echos after injecting 5 % dextrose solution. 1 cc of 50% mixture of N-Butyl - 2 - Cyanoacrylate (Histoacryl) with was Lipiodol was injected through the needle. This formed an echogenic clot in the previously anechoic aneurysm. Lipidiol was mixed for dilution and to act as cast for follow up imaging. Colour Doppler ultrasound following embolisation showed absence of flow in the aneurysm (Fig.5).

Fig. 5

The general condition of the patient improved and malena stopped the day after. Repeat endoscopy confirmed complete resolution of hemobilia. Follow up CT scan confirmed complete thrombosis of the intraheptic aneurysm (Fig.6).

Fig. 6

DISCUSSION:

A ruptured intrahepatic aneurysm causing hemobilia is serious and potentially lethal entity.Hepatic artery aneurysms are fourth in terms of incidence among visceral artery aneurysms. The etiology includes trauma (blunt, penetrating, iatrogenic), septic emboli, arteriosclerosis, and vasculpathy. They usually present at the time of rupture with a mortality of 80% from uncontrolled intraperitoneal hemorrage or due to hemobilia or may occasionally be found incidentally.

The traditional approach towards management of symptomatic hepatic artery pseudoaneurysms has evolved from surgical excision and ligation to endovascular embolisation. However, sometimes the percutaneous approach may be necessitated due to anatomical or technical limitations for transarterial embolisation. In such cases, ultrasound plays an important role as an imaging modality for guidance into these lesions. The percutaneous approach to the visceral aneurysm management has been previously described in situations where endovascular management is contra-indicated, technically challenging or unsuccessful. In these cases, various embolic materials have been injected percutaneously.

In our case, endovascular transcatheter approach was opted for superselective embolisation of the intraheptic aneurysm of the left hepatic artery using coaxial microcatheter system. However superselective navigation into the branch that had the aneurysm failed due to difficult anatomy. This prompted us to use a percutaneous approach. Ultrasonography was preferred as the imaging modality for guidance as it allowed real time dynamic scanning for precise placement of the needle in the aneurysm avoiding important blood vessels. It also has the advantage of confirming ideal needle tip position prior to embolisation by injection of saline and its flow within the aneurysm.

Moreover, the injection of embolising agent can be seen under real time scanning . In our case, we opted for N-butyl-cyanoacrylate as the embolising agent as it is widely available and relatively cheap. Cyanoacrylates are the main liquid adhesives used in the vascular system and have an important role in managing vascular abnormalities. Vascular occlusion results as these agents polymerize on exposure to the ions in blood. Although liquid adhesives or glue have been used as embolic agents for nearly three decades, experience with them outside of neuro interventional indications is limited.

This case demonstrates an unconventional approach using ultrasound guidance for treatment of hepatic artery aneurysms that become mandatory due to inherent difficulties in the well-recognized endovascular approach.