From the Guidelines
The diagnosis of Hepatic Arteriovenous (AV) malformations should be established using less invasive methods such as Doppler ultrasonography and multiphase CT, with angiography being the gold standard in uncertain cases. When diagnosing Hepatic Arteriovenous (AV) malformations, it is essential to consider the patient's clinical presentation and medical history.
- The diagnosis can be suspected by finding a thrill/bruit in the abdominal right upper quadrant, as noted by DeLeve et al. 1.
- Imaging studies such as Doppler ultrasonography can detect abnormalities with high diagnostic accuracy, including enlarged hepatic artery and intrahepatic hypervascularization 1.
- Multiphase CT can also be used to diagnose liver involvement, with all patients with symptomatic liver involvement having a markedly dilated hepatic artery and diffuse liver telangiectases that lead to a markedly heterogeneous hepatic enhancement pattern 1.
- Angiography is the gold standard in the diagnosis of LVMs, but it should only be used when the diagnosis is uncertain or when less invasive methods are inconclusive 1.
- Laboratory tests, including liver function tests, complete blood count, and coagulation studies, should be performed to assess liver function and identify any complications.
- A multidisciplinary team, including hepatologists, interventional radiologists, and vascular specialists, should be involved in the diagnostic workup to ensure comprehensive evaluation and appropriate treatment planning.
- It is crucial to differentiate liver AVMs from other liver conditions, such as cirrhosis or hepatocellular carcinoma, to provide accurate diagnosis and treatment.
- Liver biopsy is not recommended for the diagnosis of liver vascular malformations in HHT, as it is often misinterpreted and may be dangerous 1.
From the Research
Diagnosis of Hepatic Arteriovenous (AV) Malformations
- The diagnosis of hepatic AV malformations can be guided by various imaging techniques, including computed tomography angiography, magnetic resonance angiography, and Doppler ultrasonography 2, 3, 4.
- Color Doppler ultrasonography and spectral wave analysis can show and differentiate different types of hepatic vascular malformations, including arterioportal, portovenous, and arteriovenous malformations 3.
- Review of pre-procedural Doppler ultrasounds can demonstrate arterialization of portal vein waveforms, and pre-procedural cross-sectional imaging can show a network of arteries around the portal vein with early portal vein filling 2.
- Digital subtraction angiography (DSA) is usually performed for guidance during the embolization session and is essential to properly classify a specific lesion, according to its anatomy 5.
- MR angiography or computed tomography angiography (CTA) can be proposed depending on the anatomic area involved, and Doppler ultrasound is the first imaging examination that should be performed 5.
Imaging Features and Classification
- Hepatic vascular malformations can be classified into different types, including congenital and acquired types, and can be associated with various conditions, such as Rendu-Osler-Weber syndrome and cirrhotic liver 3.
- The Schobinger clinical classification is important to assess patient evolution and indicate intervention, and anatomic classifications proposed by Cho and Yakes are useful to choose the best therapeutic approach 5.
- Imaging features of hepatic vascular malformations include portal thrombosis, Budd-Chiari syndrome, hereditary hemorrhagic telangiectasia, portosystemic shunts, and congenital vascular malformations 6.
Diagnostic Challenges
- Computed tomography angiography/magnetic resonance angiography may be unable to distinguish AVMs from AVFs, and a wrong diagnosis may be made in some cases 2.
- The diagnosis of an acquired HA-PV malformation can be challenging, and a comprehensive evaluation, including imaging techniques and clinical assessment, is necessary to guide curative endovascular treatment 2.