The Source for Neurovascular News and Education

September 26, 2021


The data might be used to set benchmarks for radiation exposure that optimize patient safety, investigators say.


Stent-assisted coiling of intracranial aneurysms exposes patients to more radiation than do coiling alone, balloon-assisted coiling, or flow diversion repair, new research suggests.


Authors of the study, published online January 9, 2018, in the Journal of NeuroInterventional Surgery, hope their findings can be used to help provide benchmarks for radiation exposure in order to continue to improve patient safety.


Nicholas K Cheung, MD (Royal Hobart Hospital, Tasmania, Australia), and colleagues point out that neuroendovascular treatment for intracranial aneurysms is evolving rapidly. Dedicated fluoroscopic guidance and angiographic imaging are essential for such interventions to be effective. As the procedures become more complex, their duration increases, and patients face increasing exposure to radiation due to this essential imaging.


Advising “careful consideration of radiation safety” in these cases, they note: “Unfortunately, limited data and no benchmark thresholds are available to predict radiation related risks for different [neuroendovascular treatment] strategies.”


Efforts to reduce radiation exposure are ongoing, but many patients undergoing neuroendovascular procedures still show signs of injury, the researchers explain. “[A] literature review indicates that skin entrance doses in excess of 2 Gy may occur in 73% of [these cases], resulting in subacute deterministic changes, including alopecia, skin erythema, or scalp tenderness in up to 40% of these patients.”


One Center’s Experience


Cheung et al collected data on 249 patients with intracranial aneurysms who underwent neuroendovascular treatment at a single center by the same operator between 2010 and 2017. One-third were treated with coil embolization, 29% with balloon-assisted coil embolization, 25% with stent-assisted coil embolization, and 13% with flow diverting technology. Baseline characteristics were similar among the various patient groups.


Use of stent-assisted coil embolization was associated with longer fluoroscopy times and mean dose area product (DAP) compared with all other treatment modalities (P < 0.005). There were no significant differences between fluoroscopy times and mean DAP among each of the other treatment modalities.


Radiation Exposure by Treatment Type



(n = 83)

Balloon-Assisted Coiling

(n = 72)

Stent-Assisted Coiling

(n = 61)

Flow Diversion

(n = 33)

Fluoroscopy Time, mins

24.7 ± 12.2

28.3 ± 3.1

43.8 ± 5.5

25.6 ± 5.3

DAP, μGy m2

13,767 ± 1,445

13,508 ± 1,501

21,206 ± 2,687

13,448 ± 2,335


There were also no significant differences in fluoroscopy time or mean DAP based on whether patients were treated electively or as an emergency procedure for unruptured versus ruptured aneurysms.


“No deterministic radiation induced injuries, such as erythema or epilation, were observed among the four cohorts during clinical follow-up, after 24 hours, or at 3 months,” the researchers report.


Choosing a Strategy


“A decision on how to treat an aneurysm with [neuroendovascular therapy] is based on morphology and location of the aneurysm, its rupture status, and operator and patient related factors,” they acknowledge. “However, as device technology is continuously improving, there may be situations where an operator may be able to balance potential advantages and disadvantages of particular . . . strategies.”


Stent assisted coiling, the researchers continue, “remains the treatment of choice for complex and challenging aneurysms, where extensive neck remodeling is required.” That said, when other options “offer feasible treatment alternatives, patients and staff could benefit from reduced radiation exposure, and procedure and fluoroscopic times.”


Balloon-assisted coiling, for example, doesn’t seem to impact either radiation exposure or procedure/fluoroscopy times, they add. “When balloons provide additional procedural safety, and assist to increase aneurysmal packing density, we promote their use.”




Cheung NK, Boutchard M, Carr MW, et al. Radiation exposure, and procedure and fluoroscopy times in endovascular treatment of intracranial aneurysms: a methodological comparison. J NeuroInterv Surg. 2018;Epub ahead of print.




Cheung reports no relevant conflicts of interest.