Enhancing the role of paediatric ultrasound with microbubbles: a review of intravenous applications

Abstract

Contrast-enhanced ultrasound (CEUS) represents a complementary technique to greyscale and colour Doppler ultrasonography which allows for real-time visualization and characterization of tissue perfusion. Its inherent advantages in the child makes ultrasonography an ideal imaging modality; repeatability and good tolerance along with the avoidance of CT, a source of ionizing radiation, renders ultrasonography imaging desirable. Although currently paediatric CEUS is principally used in an "off-label" manner, ultrasonography contrast agents have received regulatory approval for assessment of paediatric focal liver lesions (FLL) in the USA. The safety of ultrasound contrast-agents is well documented in adults, as safe as or even surpassing the safety profile of CT and MR contrast agents. Except for the established intracavitary use of CEUS in voiding urosonography, i.v. paediatric applications have been introduced with promising results in the abdominal trauma initial diagnosis and follow-up, characterization and differential diagnosis of FLL and characterization of lung, pleura, renal and splenic pathology. CEUS has also been used to detect complications after paediatric transplantation, evaluate inflammatory bowel disease activity and assess tumour response to antiangiogenic therapy. The purpose of this review was to present these novel i.v. paediatric applications of CEUS and discuss their value.

Figures

Figure 1.

A 7-year-old male sustaining blunt abdominal trauma: B-mode ultrasonography (a) has identified an area of increased echogenicity and ill-defined borders (arrow) in the spleen. Contrast-enhanced ultrasound (b) is showing normal enhancement of the splenic parenchyma but no enhancement within the previously described area (arrow), establishing the diagnosis of a haematoma.

Figure 2.

A 12-year-old male diagnosed with focal nodular hyperplasia (FNH): B-mode ultrasonography (a) has identified a heterogeneous ill-defined focal liver lesion (arrow). Colour Doppler technique (b) is revealing the presence of blood vessels in the central part of the lesion (arrow). Following the administration of 2.4 ml of SonoVue™ (Bracco SpA, Milan, Italy), contrast-enhanced ultrasound (c) is demonstrating a centrifugal pattern of enhancement of the lesion (arrows) and no washout in the late phase, establishing the diagnosis of an FNH.

Figure 3.

An 11-year-old male diagnosed with a liver abscess: B-mode ultrasonography (a) is demonstrating a heterogeneous focal liver lesion (arrow) situated in the right liver lobe. Contrast-enhanced ultrasound (b) is highlighting the presence of unenhanced parts of the lesion and enhancing internal septae (arrow), with findings in keeping with an abscess.

Figure 4.

A 4-year-old male with pneumonia complicated with empyema: B-mode ultrasound (a) is showing lung consolidation and the presence of an anechoic parapneumonic effusion. Contrast-enhanced ultrasound (b) is demonstrating the enhancement of the consolidated lung parenchyma and has accurately delineated the empyema, which showed no enhancement.

Figure 5.

A 15-year-old male with incidentally found testicular lesion: B-mode ultrasonography (a) is showing a rounded isoechoic lesion (arrow) with a hypoechoic halo and central hyperechoic parts. Contrast-enhanced ultrasound (b) is showing limited internal echoes excluding the presence of a malignant tumour and establishing the diagnosis of an epidermoid tumour (arrow).