**3. Results**

Between 2008 and 2019, a total of 105 patients (male/female = 44/61; mean age 48.6 +/ − 15.8 (range 5–86)) met the inclusion criteria and were included in the study. Overall, 289 PAVMs were embolized across these 105 patients. This total included 47 (16.3%) re-perfused PAVMs in 35 (33.3%) patients. A total of 871 embolization coils and 119 vascular plugs were used. No technical difficulties occurred during placement or deployment of the embolization device.

No cerebrovascular incidents directly ascribable to the embolization procedure occurred. Small, diffuse, but clinically inconspicuous acute cerebral lesions were detected in one patient (1/105; 0.95%) on DWI-MRI at 4 h after the interventional procedure, but this patient had previously undergone embolization of a vessel with tungsten coils that had corroded over time. Since re-embolization into the previously placed tungsten coils was considered necessary and unavoidable, the possibility of new cerebral emboli resulting from small particles of corroded tungsten coil released during the re-embolization was anticipated prior to the treatment. The re-embolization of this patient was successful, and no further brain lesion and no clinical symptoms of stroke were encountered over a follow-up period of 8 years.

No other patient, whether undergoing primary embolization or re-embolization, showed any signs or symptoms of cerebrovascular incidents, and no newly developed clinically inconspicuous ischemic brain lesions were observed on MRI.

Clinical examples of diagnosis and treatment are depicted in Figures 1–4.

**Figure 1.** Cerebral DWI (b = 800) demonstrating subacute cerebral ischemia, in this case prior to embolization of multiple PAVMs. The newly developed lesion arose between screening for PAVM and the day of interventional therapy, but the patient did not exhibit any clinical signs or symptoms. This example highlights the importance of DWI for the detection of pre-existing cerebral ischemia, as well as peri-interventional cerebral insult.

**Figure 2.** (**<sup>a</sup>**–**<sup>c</sup>**) CT of a patient, demonstrating a giant complex PAVM of the right lung (**a**). The PAVM is depicted after selective catheterization of the feeding artery on DSA after manual contrast medium injection (**b**). DSA of the PAVM directly after positioning of an amplatzer vascular plug II (arrow) with already reduced flow in the PAVM (**c**).

**Figure 3.** (**<sup>a</sup>**–**<sup>c</sup>**) Re-perfused PAVM after previous treatment elsewhere. Contrast-enhanced MRA (**a**) shows two large, re-perfused PAVMs (arrows) with early enhancement of the draining vein. In (**b**) the DSA of one re-perfused PAVM is shown, depicting insufficient dense packing of coils resulting in reperfusion of the vessel. No guide wire should be used, since small thrombi from the coils might be mobilized and lead to systemic emboli. In (**c**) the second re-perfused PAVM is demonstrated, showing only small coils at the wall of the vessel. Embolization was performed proximal to the treated vessel segmen<sup>t</sup> to avoid possible migration of the coils.

**Figure 4.** *Cont*.

**Figure 4.** (**<sup>a</sup>**–**d**) A giant re-perfused PAVM in the lower right lobe. In this case, pre-interventional DSA (**a**) shows two large feeding vessels originating from a common trunk, resulting in embolization being performed at the level of the bifurcation. With DSA performed just after implantation, (**b**) shows the amplatzer plug II still connected to the wire. Optimal positioning is depicted. The dynamic series in (**c**) shows the vascular plug (arrow) still penetrable to contrast medium, however, flow is already reduced. At 5 min post-implantation of the vascular plug (**d**), the feeding artery of the re-perfused PAVM is completely occluded.
