Is Intraoperative Ultrasound a Valuable Tool for Brain Arteriovenous Malformation Diagnosis and Treatment? A Case Report

Abstract

The localization of arteriovenous malformations (AVMs) intraoperatively in the setting of an acute intracerebral hemorrhage (ICH) is crucial to avoid damage of delicate vascular structures that may even further exacerbate the bleed. Currently, surgical mapping using preoperative angiographic is the standard of practice. We report the use of intraoperative ultrasound for the diagnosis and localization of an AVM in the case of a 61-year-old female with reported iodine contrast allergy and previous severe reaction, in a setting with limited resources, without other imaging options or timely transfer to another facility readily available. Immediate surgical care was warranted to avoid further deterioration of the patient; intraoperative diagnosis and localization of the suspected underlying lesion were done using ultrasound. The ultrasound display showed tubular anechoic intertwined structures that demonstrated bidirectional flow, which is suggestive of an AVM. The intraoperative diagnosis allowed the surgeon to avoid an inadvertent approach to the vascular malformation nidus or vessels, which could have further complicated the case. We believe that intraoperative ultrasound may be valuable for the neurosurgeons today in many settings. Despite the fact that this case occurred in a scenario with limited resources and no other imaging method (such as magnetic resonance imaging (MRI), magnetic resonance angiography (MRA)) available, we advise readers not to rely solely on intraoperative ultrasound.

High-resolution micro-Doppler imaging during neurosurgical resection of an arteriovenous malformation: illustrative case

“…Arteriovenous malformations (AVMs) are vascular pathologies that can be difficult to resect, with potentially high procedural morbidity and mortality depending on factors such as their size and the number and location of the feeding arteries and draining veins. [1][2][3][4] From a pathophysiological perspective, the absence of intervening capillaries, but presence of a nidus with high-flow arteries and dilated veins, makes an AVM prone to hemorrhage. Imaging the AVM's vascular morphology is a crucial step in surgical planning, intraoperative decision-making, and therefore ultimately, treatment success.…”

“…Current clinical practice relies heavily on preoperatively acquired images including contrast-enhanced computed tomography angiography (CTA), contrast-enhanced magnetic resonance angiography (MRA), or digital subtraction angiography (DSA), the latter of which remains the gold standard for AVMs to this day. 3,5,6 Preoperatively acquired images all present the same intraoperative difficulty: they cannot completely cater to the dynamic changes in the operative field as the surgery progresses. First and foremost, the craniotomy and durotomy itself, as well as the evacuation of hematoma and circumferential isolation of the malformation, can lead to a physical shift in brain tissue, introducing a mismatch between preoperative images and the intraoperative in vivo anatomy, even when using the latest neuronavigation software.…”

“…This is particularly problematic when the neurosurgeon sees no initial surface manifestation of the malformation as an anatomical reference for the remainder of the surgery. 3,4 Intraoperative DSA [7][8][9][10] allows the surgeon to circumvent brain shiftrelated issues, but it is a laborious technique, especially when used for repeated imaging during the surgical procedure: it is timeconsuming, disrupts surgical flow, and repeatedly exposes the patient to contrast. What is more, if the contrast catheter is left in situ for longer periods of time to facilitate repeated imaging, heparin is often indicated, which is far from ideal in the context of cerebral AVM resection.…”

<p>Cerebral Arteriovenous Malformation Treatment by Full Transcranial Neuroendoscopic Approaches</p>

“…7 The estimated prevalence rate of AVMs ranges from 0.02% to 0.2%, 8,9 and the most common type is intracerebral hemorrhage, with an annual bleeding rate of approximately 2.2% for unruptured AVMs and 4.5% for ruptured AVMs. 10 AVM is a dynamic disease, and the treatment may differ based on whether the patient is symptomatic, the Spetzler-Martin grade, whether the case is an emergency and so on. The final goal of cAVM treatment is the prevention of hemorrhage and the complete disappearance of the nidus on angiography.…”