Peripheral Vascular Anomalies – Essentials in Periinterventional Imaging

Abstract

Background Peripheral vascular anomalies represent a rare disease with an underlying congenital mesenchymal and angiogenetic disorder. Vascular anomalies are subdivided into vascular tumors and vascular malformations. Both entities include characteristic features and flow dynamics. Symptoms can occur in infancy and adulthood. Vascular anomalies may be accompanied by characteristic clinical findings which facilitate disease classification. The role of periinterventional imaging is to confirm the clinically suspected diagnosis, taking into account the extent and location of the vascular anomaly for the purpose of treatment planning. Method In accordance with the International Society for the Study of Vascular Anomalies (ISSVA), vascular anomalies are mainly categorized as slow-flow and fast-flow lesions. Based on the diagnosis and flow dynamics of the vascular anomaly, the recommended periinterventional imaging is described, ranging from ultrasonography and plain radiography to dedicated ultrafast CT and MRI protocols, percutaneous phlebography and transcatheter angiography. Each vascular anomaly requires dedicated imaging. Differentiation between slow-flow and fast-flow vascular anomalies facilitates selection of the appropriate imaging modality or a combination of diagnostic tools. Results Slow-flow congenital vascular anomalies mainly include venous and lymphatic or combined malformations. Ultrasound and MRI and especially MR-venography are essential for periinterventional imaging. Arteriovenous malformations are fast-flow vascular anomalies. They should be imaged with dedicated MR protocols, especially when extensive. CT with 4D perfusion imaging as well as time-resolved 3D MR-A allow multiplanar perfusion-based assessment of the multiple arterial inflow and venous drainage vessels of arterio-venous malformations. These imaging tools should be subject to intervention planning, as they can reduce procedure time significantly. Fast-flow vascular tumors like hemangiomas should be worked up with ultrasound, including color-coded duplex sonography, MRI and transcatheter angiography in case of a therapeutic approach. In combined malformation syndromes, radiological imaging has to be adapted according to the dominant underlying vessels and their flow dynamics. Conclusion Guide to evaluation of flow dynamics in peripheral vascular anomalies, involving vascular malformations and vascular tumors with the intention to facilitate selection of periinterventional imaging modalities and diagnostic and therapeutic approach to vascular anomalies. Key Points: Citation Format

Imaging of peripheral vascular malformations — current concepts and future perspectives

“…Contrast-enhanced multi-slice CT allows for rapid assessment of vascular malformations with precise evaluation of the feeding and draining vessels, though the major disadvantage of this modality is the significant dose of ionizing radiation [ 36 ], which is particularly relevant in children [ 37 ]. Accordingly, CT is not recommended as a routine diagnostic modality but should be reserved for certain cases, where MRI is either not possible or expected to not provide enough information for proper treatment planning [ 13 ], which may allow to reduce procedure time and radiation dose during DSA [ 38 ]. This is ideally performed by time-resolved CTA and CT venography (4D CT imaging) over a wide z -axis coverage combined with low tube voltage settings [ 39 ].…”

“…Here, periprocedural angiography aims to understand specific flow dynamics, which frequently change in control angiography during embolization. In slow-flow malformations, direct percutaneous phlebography offers detailed information on intralesional flow patterns and potential connections to the draining deep venous system of the lesion before sclerotherapy [ 13 ]. Diagnostic arterial angiography is not indicated in slow-flow malformations, as they only contain hypodynamic small arteriovenous fistulas [ 40 ].…”

“…Using direct percutaneous phlebography, VMs present as clusters of dysplastic veins with contrast pooling without any signs of relevant arterio-venous shunting [ 13 ]. Due to the informative superiority, the non-invasive nature, and the lack of ionizing radiation of the available imaging alternatives, phlebography is not the first diagnostic modality of choice in a child pre-procedural, but can provide additional information in location, extension, and patency of the lesion during the procedure as well as its drainage to deep veins.…”

“…In the use of a wide-ranging scan field, perfusion dynamics of the entire affected limb can be evaluated. As perfusion imaging requires repetitive scanning over a certain time period, the radiation burden has to be critically weighted against the potential benefits [ 13 , 81 , 82 ]. In case of further specific situations, such as if the AVM involves bone, CT may be of particular interest in the assessment of the surrounding tissues [ 64 ].…”

“…Imaging should be able to assess the exact flow dynamics in order to differentiate the various types of vascular malformations (fast-flow vs. slow-flow lesions), as to date there is a high rate of misdiagnosis [ 2 ]. In addition, the anatomical extent with tissue involvement and affected compartments should be precisely demonstrated for an interdisciplinary and multimodal treatment planning [ 13 ]. We performed a PubMed search of reports focusing on imaging of extracranial vascular malformations using the search terms “Imaging,” “Vascular malformations” and “Vascular anomalies” with a focus on recently published work including new treatment strategies.…”