Role of contrast-enhanced ultrasound in the evaluation of post-liver transplant vasculature

Contrast-enhanced ultrasound (CEUS) in the follow-up of abdominal solid organ trauma: an international survey prior to the PseAn study

BACKGROUND

The blunt and penetrating abdominal trauma follow-up relies on contrast CT scan to detect solid organ injuries. CEUS is not widely used worldwide, despite its accuracy and feasibility in identifying parenchymal and vascular lesions. This survey aims to define the current use of CEUS in Trauma Centers and the expectations of Emergency Surgeons regarding its role.

METHODS

We sent an online questionnaire composed of 10 questions to trauma physicians worldwide during the period of September 2022 to March 2023.

RESULTS

59 participants from 53 different centers answered the questionnaire. 76.2% of the enrolled participants have CEUS available at their Institution, and 49.2% think that it can replace CT scan. Contrast-CT scan remains the preferred option in the follow-up of blunt liver (69.5%), spleen (72.9%) and kidney (76.3%) injuries, followed by CEUS which is used in 18.6% for liver, 20.3% for spleen and 15.3% for kidney injuries. The results are similar for penetrating abdominal trauma, with contrast CT scan being the first-line imaging technique (91.5% for liver, 91.5% for spleen and 88.1% for kidney injuries), followed by CEUS (5.1% for liver, 5.1% for spleen and 6.8% for kidney injuries).

CONCLUSIONS

Our survey shows that CEUS is still underutilized in the follow-up of abdominal trauma, even though many emergency surgeons consider it as a valid alternative to contrast CT scan.

Beyond conventional physical examination in hepatology: POCUS

Point-of-care ultrasound (POCUS) refers to the use of ultrasound imaging through pocket-sized sonographic devices at the patient's bedside, to make a diagnosis or direct a procedure and immediately answer a clinical question. Its goal is to broaden the physical examination, not to replace conventional ultrasound studies. POCUS has evolved as a complement to physical examination and has been adopted by different medical specialties, including hepatology. A narrative synthesis of the evidence on the applications of POCUS in hepatology was carried out, describing its usefulness in the diagnosis of cirrhosis of the liver, metabolic dysfunction-associated steatotic liver disease (MASLD), decompensated cirrhosis, and portal hypertension. The review also encompasses more recent applications in the hemodynamic evaluation of the critically ill patient with cirrhosis of the liver, patients with other liver diseases, as well as in the ultrasound guidance of procedures. POCUS could make up part of the daily clinical practice of gastroenterologists and hepatologists, simplifying the initial evaluation of patients and optimizing clinical management. Its accessibility, ease of use, and low adverse event profile make POCUS a useful tool for the properly trained physician in the adequate clinical setting. The aim of this review was to describe the available evidence on the usefulness of POCUS in the daily clinical practice of gastroenterologists and hepatologists.

Immediate and Late Complications After Liver Transplantation

Other than rejection, hepatic artery and portal vein thrombosis are the most common complications in the immediate postoperative period with hepatic arterial thrombosis more common and more devastating. Hepatic artery stenosis is more common 1 month after transplantation, whereas portal and hepatic vein stenosis is more often seen as a late complication. Ultrasound is the first-line imaging examination to diagnose vascular complications with contrast-enhanced CT useful if ultrasound findings are equivocal. MR cholangiography is often most helpful in diagnosing bile leaks, biliary strictures, and biliary stones.

The Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management

PURPOSE

To illustrate diagnostic and interventional imaging for the characterization and treatment of portal vein thrombosis (PVT).

INTRODUCTION

The broad spectrum of congenital and acquired PVT manifestations is illustrated, with a focus on the pediatric population; diagnostic and interventional imaging techniques are described.

DESCRIPTION

PVT frequently presents as an incidental finding at imaging in the screening for liver diseases or for other unrelated reasons. PVT can be classified based on: extension (intrahepatic, extrahepatic, involving the spleno-mesenteric tract, etc.); degree (partial or complete); onset (acute or chronic); and with or without cavernomatous transformation. This comprehensive review relies on the experience gained from a large series of congenital and acquired PVT in a referral center for pediatric and adult liver transplantation. Diagnostic and interventional imaging techniques are described, including: color-Doppler and contrast-enhanced Ultrasound; CT and MR angiography; retrograde portography; percutaneous transhepatic, transplenic, and transmesenteric portography; transjugular intrahepatic portosystemic shunt creation. Pre- and post-operative imaging assessment of the surgical meso-rex bypass is discussed. The description is enriched with an original series of pictorial imaging findings.

CONCLUSION

PVT is a clinical condition associated with significant morbidity and mortality. Diagnostic and interventional imaging plays a crucial role in both conservative and operative management.

Liver Transplant Imaging prior to and during the COVID-19 Pandemic

Background

The suspension of the surgical activity, the burden of the infection in immunosuppressed patients, and the comorbidities underlying end-stage organ disease have impacted transplant programs significantly, even life-saving procedures, such as liver transplantation.

Methods

A review of the literature was conducted to explore the challenges faced by transplant programs and the adopted strategies to overcome them, with a focus on indications for imaging in liver transplant candidates.

Results

Liver transplantation relies on an appropriate imaging method for its success. During the Coronavirus Disease 2019 (COVID-19) pandemic, chest CT showed an additional value to detect early signs of SARS-CoV-2 infection and other screening modalities are less accurate than radiology.

Conclusion

There is an emerging recognition of the chest CT value to recommend its use and help COVID-19 detection in patients. This examination appears highly sensitive for liver transplant candidates and recipients, who otherwise would have not undergone it, particularly when asymptomatic.