Diagnostic imaging in the study of visceral involvement of hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber disease, is an autosomal-dominant vascular disease characterised by mucocutaneous or visceral angiodysplastic lesions. Its diagnosis is exclusively based on clinical criteria. The brain, lungs and liver, in growing order of prevalence, are the most frequently involved organs. Diagnostic imaging based on ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI) and digital subtraction angiography (DSA) has a fundamental role in detecting visceral involvement in HHT patients and is therefore crucial for the prognostic assessment and therapeutic approach. Arteriovenous shunts are the most common cerebrovascular malformations (CVMs). MRI and CT angiography are the methods of choice for diagnosing cerebral involvement, and it is debated whether MRI could be considered as a screening examination on account of its noninvasiveness. Pulmonary arteriovenous malformations, diffuse telangiectases or high-flow, low-pressure shunts between pulmonary arteries and veins can be studied with contrast-enhanced US, but multidetector CT seems to provide the most comprehensive evaluation of their angioarchitecture, whereas angiography has a predominant role in treatment. Liver involvement is frequent and characterised by the presence of intrahepatic shunts, disseminated intraparenchymal telangiectases and other vascular lesions. US is useful for detecting hepatic lesions but should be completed by more accurate imaging methods such as multidetector CT and MRI.