Contrast-enhanced ultrasound (CEUS) in blunt abdominal trauma

Abstract

Baseline ultrasound is essential in the early assessment of patients with a huge haemoperitoneum undergoing an immediate abdominal surgery; nevertheless, even with a highly experienced operator, it is not sufficient to exclude parenchymal injuries. More recently, a new ultrasound technique using second generation contrast agents, named contrast-enhanced ultrasound (CEUS) has been developed. This technique allows all the vascular phase to be performed in real time, increasing ultrasound capability to detect parenchymal injuries, enhancing some qualitative findings, such as lesion extension, margins and its relationship with capsule and vessels. CEUS has been demonstrated to be almost as sensitive as contrast-enhanced CT in the detection of traumatic injuries in patients with low-energy isolated abdominal trauma, with levels of sensitivity and specificity up to 95%. Several studies demonstrated its ability to detect lesions occurring in the liver, spleen, pancreas and kidneys and also to recognize active bleeding as hyperechoic bands appearing as round or oval spots of variable size. Its role seems to be really relevant in paediatric patients, thus avoiding a routine exposure to ionizing radiation. Nevertheless, CEUS is strongly operator dependent, and it has some limitations, such as the cost of contrast media, lack of panoramicity, the difficulty to explore some deep regions and the poor ability to detect injuries to the urinary tract. On the other hand, it is timesaving, and it has several advantages, such as its portability, the safety of contrast agent, the lack to ionizing radiation exposure and therefore its repeatability, which allows follow-up of those traumas managed conservatively, especially in cases of fertile females and paediatric patients.

Figures

Figure 1.

Contrast-enhanced ultrasound (CEUS) protocol. CEUS is performed in sequence before exploring the kidneys, then the liver and finally the spleen.

Figure 2.

Child, hepatic injury. (a) Baseline ultrasonography shows a mild hyperechoic area in the liver parenchyma; (b) contrast-enhanced ultrasound (CEUS) demonstrates a well-defined hypoechoic lesion (white arrow); (c) axial scan and (d) coronal CT reconstruction confirm the hepatic lesion, corresponding in size and shape to that observed at CEUS.

Figure 3.

Child, renal injury. (a) Baseline ultrasonography shows echostructural inhomogeneity of the middle of the left kidney; (b) contrast-enhanced ultrasound (CEUS) demonstrates a subtle renal laceration (white arrow) and a subcapsular haematoma surrounding the kidney; (c) axial CT scan and (d) coronal reconstruction confirm the CEUS findings (arrowheads).

Figure 4.

Child, hepatic injury. (a) Baseline ultrasonography shows only echostructural inhomogeneity on VII hepatic segment; (b–c) contrast-enhanced ultrasound demonstrates a laceration and parenchymal haematoma (arrowheads) involving the hepatic capsule, with hyperechoic bubbles indicating active bleeding (white arrow); (d) axial CT scan and (e) coronal reconstruction confirm the involvement of hepatic capsule and the active bleeding in peritoneal cavity.

Figure 5.

Child, splenic trauma. (a) Baseline ultrasonography shows swelling and echostructural inhomogeneity of the lower pole of the spleen (arrowhead); (b) contrast-enhanced ultrasound shows a large triangular-shaped hypoechoic area at the lower pole of the spleen (white arrow), corresponding to an area of devascularization; (c) axial CT scan and (d) coronal view confirm the triangular-shaped not vascularized area.

Figure 6.

Young females, hepatic injury. (a) Baseline ultrasonography, irregular hyperechoic area in the right lobe. Capsular involvement is not demonstrated; (b) contrast-enhanced ultrasound shows multiple lacerations in the right hepatic lobe, involving the capsular surface; (c) axial CT scan and (d) coronal view confirm a huge irregular-shaped laceration and the capsular rupture.

Figure 7.

Males, hepatic injury. (a) Baseline ultrasonography shows a large hyperechoic area in the right lobe; (b) on contrast-enhanced ultrasound (CEUS), compared with conventional ultrasound, the lesion appears to have better defined margins (white arrows) because of a better definition of peripheral components; (c) axial CT scan and (d) coronal reconstruction show finding similar to CEUS.

Figure 8.

Young girl, splenic injury. (a) Baseline ultrasonography not clearly depicts the upper pole of the spleen; (b) contrast-enhanced ultrasound demonstrates a complete fracture of the subphrenic region of the spleen, involving the capsule (white arrow), which is confirmed on (c) axial CT scan and (d) coronal view.

Figure 9.

Females, splenic and renal injury. (a–b) Contrast-enhanced ultrasound shows a subtle lesion of splenic parenchyma, involving the capsule, which was not evident on baseline ultrasonography. A large cyst of renal upper pole is also depicted; (c–d) axial CT scan confirms the little lesion of the spleen and a subcapsular renal haematoma, due to the rupture of the upper pole cyst.

Figure 10.

Child, renal trauma. (a) Baseline ultrasonography shows a mild hyperechoic area in the middle-third of the right kidney; (b) contrast-enhanced ultrasound demonstrates a renal fracture with an associated perirenal collection (arrowheads) and evidence of hyperechoic spots within it (white arrow), corresponding to active bleeding; (c–d) axial CT scan and coronal view confirm the renal fracture, the perirenal haematoma and active bleeding (black arrow).

Figure 11.

Child, renal trauma. (a) Baseline ultrasonography shows only a fine cortical parenchymal inhomogeneity of the left kidney with perirenal fluid collection; (b) contrast-enhanced ultrasound shows a large renal fracture and highlights very well the presence of perirenal fluid (arrowheads); (c) axial CT scan in the venous phase demonstrates the renal fracture and confirms the perirenal fluid; (d) axial CT scan in the late phase shows the iodinated urine leakage (white arrows) in the perirenal space (urinoma).

Figure 12.

Child, pancreatic injury. (a–b) Baseline ultrasonography with CD imaging does not show any pancreatic lesion. c) Contrast-enhanced ultrasound shows swelling of pancreatic body and allows to suspect subtle lesions of the pancreatic body and tail (white arrows), associated with pre-pancreatic fluid collection (arrowhead). (c–d) Axial CT scans confirm the pancreatic tail lesion (white arrow) with pre-pancreatic fluid collection.

Figure 13.

Males, splenic injury. (a) Baseline ultrasonography performed 3 days after trauma shows a subtle hypoechoic rim in the splenic parenchyma; (b) contrast-enhanced ultrasound (CEUS) demonstrates a clear hyperechoic spot (white arrow), surrounded by hypoechoic area, which is due to an arteriovenous fistula; (c) axial CT scan performed immediately after trauma shows only a small contusion in the splenic parenchyma; (d) 3 days later, axial CT scan performed on the basis of CEUS findings confirms the arteriovenous fistula (white arrow).

Figure 14.

Males, splenic trauma treated by embolization. (a) Contrast-enhanced ultrasound (CEUS) performed immediately after the embolization shows an hypoechoic devascularized area at the upper pole of the spleen, in the site of embolization; (b) CEUS performed 2 months later shows the reduction in size of the splenic ischaemic area (arrowhead); (c–d) MRI performed at the same time of the second CEUS allows to better define the size and the extent of the devascularized area and provides a temporal stage of the lesion.

Figure 15.

(a) Baseline ultrasonography shows an inhomogeneous hypoechoic–hyperechoic parenchymal lesion of the liver and a subcapsular haematoma; (b) contrast-enhanced ultrasound (CEUS) allows to depict the hepatic laceration and the parenchymal and subcapsular haematoma well; (c) axial CT scan confirms the CEUS findings; (d–e) MRI, performed 4 months later, demonstrates the reduction in size of the lesion and the disappearance of subcapsular haematoma well.

Figure 16.

Child, renal trauma. (a) Baseline ultrasonography shows only an hyperechoic area at the lower pole of the right kidney (white arrow); (b) contrast-enhanced ultrasound demonstrates very well the incomplete renal fracture and a little amount of perirenal haematoma (arrowheads); (c) axial CT scan in venous phase shows the subtle renal laceration and the perirenal fluid collection; (d) axial CT scan in the late phase demonstrates the iodinated urine leakage (black arrows) due to the urinary tract lesion.