1. To review classification and description.
2. To identify the role of imaging modalities.
3. To understand the role of interventional radiologist in management and treatment.
Vascular malformations are rare and therefore the diagnosis is often unknown to a general radiologist. It is important to differentiate a congenital vascular malformation from an infantile hemangioma. Congential vascular malformations a have a specific anamnesis, which is often the major clue to the final diagnosis. There are 3 main types of congenital vascular malformations. Arterial (high flow with direct fistula), venous (low flow) and lymphatic. There are some related vascular tumours like capillary malformation and port-wine stains. There are several syndromes in relation to vascular malformations. The most known is Klippel-Trenaunay-Weber syndrome. For a general radiologists it is important to recognise a vascular malformation. Treatment and further work-up diagnosis should only be undertaken in centres of expertise. Only malformations that give complaints like pain, bleeding or cosmetic issues should be treated. Both embolisation (for high flow) and local sclerotherapy (for low flow) are used to treat vascular malformations.
1. To learn about classification and terminology.
2. To understand the role of US, CT and MRA in diagnostic assessment.
3. To learn the optimal imaging algorithm for diagnosis and follow-up.
Vascular malformations are categorised into the low-flow malformations and high-flow malformations. From imaging methods is expected to distinguish between the low-flow lesions and high-flow lesions, localisation, volume and range of lesion and relationship to the surrounding tissues and organs. Color doppler ultrasonography (DUS) can offer good differentiation between high-flow and low-flow lesions. Magnetic resonance (MR) offers good differentiation between high-flow and low-flow lesions also, and moreover good evaluation of volume and extent of lesion, good interpretation of anatomical relationship to the surrounding tissues and organs. On DUS the low-flow malformations are demonstrated as hypoechogenic or heterogeneous lesions with minimal flow inside, flow during augmentation and normal arterial flow volumes and normal high arterial resistance flow. The high-flow malformations are heterogeneous lesions with tortuous feeding arteries, high velocity and low-resistance flow in feeding arteries, multiple arteriovenous shunts and pulsatile flow in draining veins. On MR the low-flow malformations typically have low signal intensity in T1 weighted images in abnormal vascular structures and high signal intensity in T2 weighted images, whereas the high-flow lesions usually demonstrate a signal voids in abnormal vascular structures on most sequences. At follow-up DUS demonstrates thrombosis and fibrosis of the low-flow lesion. In the high-flow lesion the waveform will be normalised and the resistive indexes and the flow volumes will become normalised as well. MR demonstrates thrombosis and fibrosis of low-flow malformation by the loss of high signal in T2 weighted images and loss of signal voids in high-flow lesions.
1. To recognise the indications and the real need for treatment.
2. To learn about technical approach and how to plan the intervention.
3. To understand possible limitations and the final result prediction.
Vascular anomalies, are divided in two different categories which carry different prognosis and management: "Vascular tumors" and "Vascular malformations" (VM). Their precise identification is crucial and involves a good knowledge of the biological classification published by Mulliken and Glowacki and that has recently been updated by the International Society for the Study of Vascular Anomalies (ISSVA). Vascular malformations are always congenital and grow with the child. They can involve type of vessels solely or combined with others. A rheologic differentiation between low and high flow malformations is essential to characterise the seriousness of the lesion. Interventional radiology (IR) plays major role in both curative and palliative treatments of these VM. Once understanding the nature and high/low flow characteristics of VM, transcatheter/endovascular (transarterial or transvenous) or direct percutaneous puncture under imaging guidance are the 2 main techniques for treating these lesions. Depending on the type, nature, location and surroundings of the VM, one should decide the best strategy for treatment. Another key point is to decide whether to use embolisation or sclerotherapy. Again, the type, location of the VM is vital and the patient based decision is to be made carefully by a multidisciplinary team. Operator’s experience is of most importance in determining all of the above variables, together with the local circumstances. There are many different types of embolic and sclerotherapy agents available around the world.
1. To understand the specifics of vascular malformations in children.
2. To recognise when to observe and when to intervene.
3. To learn about interventional techniques used and results of treatment.
Haemangiomas are by far the most common type of vascular anomaly that present in childhood. Haemangiomas are benign vascular tumours; several subtypes exist. Infantile haemangiomas are the commonest subtype and the vast majority of these require no intervention at all, because they involute spontaneously over the first few years of childhood. These well defined vascular masses have a highly characteristic growth pattern and typical imaging features. They can be distinguished from the rarer congenital haemangiomas by their clinical presentation. Rarer benign childhood vascular tumours include kaposiform haemangioendotheliomas (KHEs) and tufted angiomas, both of which are associated with thrombocytopaenia and have characteristic imaging features to distinguish them from haemangiomas. Unlike vascular tumours, vascular malformations are present from birth and grow slowly in childhood. Lymphatic malformations (LMs) tend to present earlier and are encountered much more commonly in children than adults. Macrocystic LMs consist of thin-walled cysts containing lymph or clot and microcystic lesions appear more solid. Ultrasound is often sufficient to make a diagnosis but MRI may be required to determine the extent of deep-seated lesions. Small lesions may not require treatment; larger lesions are usually treated with percutaneous image-guided sclerotherapy, though surgery has an important adjunctive role in debulking larger lesions. Finally, some children present with complex overgrowth, often of just one limb, which is associated with a vascular malformation. These patients require expert input from a multidisciplinary team and imaging is key.