Finding the Nidus: Detection and Workup of Non–Central Nervous System Arteriovenous Malformations

Abstract

Vascular anomalies are a diverse group of pathologic conditions. They have different manifestations, natural histories, and treatments. Compared with other vascular malformations, arteriovenous malformations (AVMs) are considered the most symptomatic and difficult to manage. AVMs inherently progress and have a high rate of recurrence after treatment. Imaging helps provide an accurate and early diagnosis, which can then be used to direct appropriate management, with embolization evolving as the primary therapy. Thus, radiology plays a crucial role in the detection, workup, and management of AVMs. Ultrasonography (US) is a useful initial imaging modality, particularly when AVMs involve the extremities or a superficial or accessible location. Limitations include poor identification of soft-tissue and bone components, as well as suboptimal evaluation of deep or complex AVMs. Magnetic resonance (MR) angiography is the preferred imaging modality for AVMs and should be considered in any symptomatic patient or in the initial evaluation of vascular anomalies that are equivocal at US. Computed tomographic angiography should be reserved for those patients who are unable to undergo MR angiography or for evaluation of acute symptoms, such as bleeding or airway compromise. Conventional catheter-based angiography is useful for real-time depiction and evaluation of AVMs, particularly in the planning and execution of endovascular treatment and in the diagnosis of an AVM when findings from noninvasive imaging are equivocal for a high-flow component. As with the diagnostic workup, MR angiography is the preferred posttreatment modality. (©)RSNA, 2016.

Clinical Presentation, Diagnosis, and Management of Mesenteric Vasculopathies in Pediatric Patients

“…9 Hepatic AVMs can be challenging to diagnose, many are clinically silent and not identified until later in life or when serious complications ensue, such as hemorrhage or high output cardiac failure. 18,19 Early detection and treatment is imperative to avoid these complications. The etiology of an isolated hepatic AVM is not well understood and clinical experience is limited to case reports.…”

“…Hepatic AVMs are more often reported in association with other congenital anomalies or in genetic syndromes, such as hereditary hemorrhagic telangiectasia (also known as Osler-Weber-Rendu syndrome) and Parks Weber syndrome. 18 Ultrasound imaging can aid in early diagnosis and distinction from other vascular anomalies. Prenatal or perinatal ultrasound imaging can reveal a cluster of dilated anechoic vessels with turbulent flow on color and spectral Doppler acquisition.…”

“…Embolic materials can vary from operator to operator, but include vascular coils, microvascular plugs, dehydrated alcohol 98% by volume, nbutyl cyanoacrylate (nBCA), and Onyx ® . 18 Proximal feeding artery embolization should be avoided due to nontarget injury/ischemia and potential loss of access for future treatments. The nidus should be the primary target site when treating AVMs.…”

Vascular Anomalies (Part II): Interventional Therapy of Peripheral Vascular Malformations

“…Fast-flow vascular malformations are defined as abnormal shunts between arteries and veins without an intervening capillary bed [65]. In arteriovenous malformations (AVMs) shunting occurs through a network of vessels, the nidus.…”

“…In arteriovenous malformations (AVMs) shunting occurs through a network of vessels, the nidus. An arteriovenous fistula (AF) is defined as blood shunting through a single arterialized vein [65]. AVMs can arise anywhere in the body and therefore have a wide range of clinical manifestations.…”