RC 115 - Peripheral vascular malformations: light after darkness
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.
Treatment of peripheral vascular malformations is a combination of diagnostics, skills and experience. This treatment is done by specialised interventional radiologists in dedicated centres. Treatment is always a team effort. There is a wide variety of diagnostic pathways used to establish the final diagnosis and to plan treatment. These pathways will be discussed. Based on the clinical diagnosis specific imaging algorithms can be used. In the workshop this will be discussed. Treatment of peripheral vascular malformations is often not a medical necessity but mainly closely related to the wishes and expectations of the patients. Every procedure is tailored by this “shared dissection making” and, therefore, planning of a treatment procedure should also be patient tailored. How to define success is, therefore, sometimes difficult. This planning of treatment will also be discussed. Children are a specific entity within the spectrum of vascular malformations and special knowledge is needed not only to treat but also to support these patients and their family. Also in children interventional techniques are tailored and this will be discussed in the session.
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 categorized into the low-flow malformations and high-flow malformations. From imaging methods it 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. Colour 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 heterogenous 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 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 normalised and the resistive indexes and the flow volumes will become normalized 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 - how to plan the intervention?
3. To understand possible limitations and the final result prediction.
Vascular anomalies are divided into two different categories which carry different prognosis and management: "vascular tumours" 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 growth 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 characterize the seriousness of the lesion. Interventional radiology (IR) plays major role in both curative and palliative treatments of these 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 embolization 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.
The current accepted method for classification of vascular malformations is straightforward and clinically relevant. Vascular malformations can be divided into high flow lesions such as arteriovenous malformation (AVM) or low flow lesions such as venous or lymphatic malformations. In children, 90% of vascular anomalies can be diagnosed by clinical history and examination alone. Imaging predominantly with US or MRI can confirm the diagnosis, evaluate extent of a lesion or flow within it. In children ultrasound is particularly useful for aiding the diagnosis. Many vascular malformations require no treatment, if they are not causing symptoms. A multidisciplinary team approach to the management of these conditions is vital. Non-interventional treatments such as physiotherapy and occupational therapy are vital. The use of compression garments can help symptomatically in venous malformations. Interventional radiology plays a role in treatment principally with injection sclerotherapy of low flow lesions and embolization of the much rarer AVM. Many sclerotherapy agents are available with sodium tetradecyl sulphate the most commonly used for venous malformations and doxycycline commonly used for lymphatic malformations. Different sclerotherapy agents have different characteristics and uses which will be covered. Symptomatic relief is often achieved with treatment but multiple treatment episode may be needed to achieve the wanted outcome. Ensuring the child and family understand this is vital to ensure they are satisfied with the management of the condition.