Contrast-enhanced ultrasound (CEUS) of the abdominal vasculature

Abstract

Vascular diseases account for a significant proportion of abdominal pathology and represent a common referral source for abdominal ultrasonographic examinations. B-mode, color Doppler, and spectral Doppler analyses are well-established in the evaluation of abdominal blood vessels although they may occasionally be limited by lower sensitivity for slow flow visualization or the deeper location of abdominal vascular structures. The introduction of microbubbles as ultrasonographic contrast agents has rendered contrast-enhanced ultrasound (CEUS), a valuable complementary ultrasonographic technique, which is capable of addressing clinically significant problems and guiding patient management. The purpose of this pictorial review is to analyze the use of CEUS in the evaluation of abdominal vascular pathology and illustrate such applications by presenting representative images. Pathology discussed includes abdominal aortic aneurysm, post-endovascular treatment aorta, portal vein thrombosis, abdominal vascular trauma, and organ transplantation along with its complications.

Keywords: Aneurysm; Aorta; Contrast-enhanced ultrasound; Endoleak; Portal vein; Trauma.

Fig. 1

Routine post-elective EVAR follow-up scan from a 83-year-old man showed an expanding aneurysmal sac. CEUS was performed to look for endoleak. Longitudinal view of an aortic stent graft within the dilated aneurysm sac (between short arrows). CEUS image demonstrates microbubble ultrasound contrast within the patent aortic stent graft with no evidence of “endoleak” (long arrow)

Fig. 2

Longitudinal views of aortic stent grafts demonstrates type 1 (row A), type 2a (row B), and type 3 (row C) endoleaks. Each row consists of sequential CEUS images (left to right) demonstrating UCA jets (long arrows) originating from the aortic stent grafts from ineffective proximal seal (row A, type 1), persistent filling of the aneurysmal sac from the inferior mesenteric artery (row B, type 2a), and inadequate sealing of the overlapping main aortic body and iliac stent (row C, type 3). The aneurysmal sac is filled with UCA (broken arrows) with central thrombosis (short arrows)

Fig. 3

Longitudinal views of aortic graft. Sequential CEUS images (A–C) demonstrates UCA jets (arrows) originating through the stent graft resulting in a type 4 endoleak due to porosity of the stent graft fabric

Fig. 4

Patient with history of invasive retroperitoneal sarcoma compressing on IVC which was resected (surgical clips, open arrow). She subsequently presented with bilateral lower limb pitting edema. Imaging studies were performed to exclude IVC thrombus (A) coronal CECT (B) Color Doppler US and (C) Gray-scale US demonstrate near occlusive thrombus within the IVC (arrows). (D) The thrombus shows enhancement with microbubble ultrasound contrast imaging in keeping with tumor thrombus (arrow)

Fig. 5

CEUS image demonstrates non-occlusive bland thrombosis of the left portal vein (arrows)

Fig. 6

A 66-year-old male with liver cirrhosis developed hepatorenal syndrome. Color Doppler US failed to demonstrate the presence of portal flow likely due to slow flow (A, arrow). CEUS was performed instead of CECT due to poor renal function. CEUS demonstrated a patent portal vein (B, arrows). Isolated CEUS image from the same patient shows recanalisation of large umbilical vein (C, arrows) surrounded by large volume ascites (black area) in keeping with established portal hypertension

Fig. 7

A 14-year-old boy fell downstairs and sustained a grade 4 liver laceration. CECT (axial) shows linear area of liver laceration (A, arrow). CEUS of the liver was performed 5 days post-trauma to evaluate the injury. Sequential CEUS images (B and C) demonstrate a pseudoaneurysm (arrow in B, between cursors and arrow in C). Image B is taken during arterial phase akin to the CT angiographic phase with microbubble contrast only seen in the hepatic artery and pseudoaneurysm. The later image C shows the presence of microbubble contrast within the liver. The part of the liver which lacks microbubble contrast correspond to area of liver laceration. The pseudoaneurysm was confirmed during conventional hepatic artery catheter angiography (D, arrow) and subsequently successfully embolized with vascular coils

Fig. 8

A 60-year-old female developed hepatic artery thrombosis post-liver transplantation. The CEUS (A) and axial CECT (B) comparison images demonstrate proximal hepatic artery thrombosis (solid arrow) with lack of microbubble ultrasound contrast or iodinated contrast vascular enhancement. The coeliac trunk is labeled as CEL and the splenic artery is indicated by open arrows. There is widespread resultant geographical areas of hepatic infarction present on the CECT and CEUS images (arrows, C and D)

Fig. 9

CEUS and CECT images from two cases of splenic artery pseudoaneurysm formation (arrows). A (CEUS) and B (CECT, axial) from a 47-year-old male who developed splenic artery pseudoaneurysm encased by necrotising pancreatitis with large peripancreatic collection and completely infarcted non-enhancing spleen. C (CEUS) and D (CECT, coronal) from a 43-year-old male who suffered blunt abdominal trauma demonstrates a small peri-splenic hematoma (broken arrows) and a pseudoaneurysm (arrow) adjacent to the laceration (open arrow)

Fig. 10

Images from a 40-year-old male with suspected renal colic. Coronal CECT (A) shows a giant branch renal artery pseudoaneurysm (arrow) which was coil embolized (B). Post-procedural follow-up CEUS image (C) demonstrates the absence of microbubble ultrasound contrast within the aneurysm sac (arrow) in keeping with complete occlusion of the pseudoaneurysm. Grey-scale image shows echogenic thrombus within the pseudoaneurysm (D, arrow)

Fig. 11

Imaging findings in a patient with renal infarction. Oblique sagittal MDCTA image (A) showing the kidney in long-axis, revealed the presence of an upper pole renal infarct (arrowheads). On follow-up US, long-axis B-mode technique (B) did not visualize any significant alterations in parenchymal echogenicity. Respective color Doppler technique image (C) demonstrated less blood flow signals on the upper half of the kidney (arrowheads), in keeping with the infarct. Respective CEUS image (D) readily confirmed the diagnosis of renal infarction (arrowheads)