CBCT-based 3D MRA and angiographic image fusion and MRA image navigation for neuro interventions

Abstract

Digital subtracted angiography (DSA) remains the gold standard for diagnosis of cerebral vascular diseases and provides intraprocedural guidance. This practice involves extensive usage of x-ray and iodinated contrast medium, which can induce side effects. In this study, we examined the accuracy of 3-dimensional (3D) registration of magnetic resonance angiography (MRA) and DSA imaging for cerebral vessels, and tested the feasibility of using preprocedural MRA for real-time guidance during endovascular procedures.Twenty-three patients with suspected intracranial arterial lesions were enrolled. The contrast medium-enhanced 3D DSA of target vessels were acquired in 19 patients during endovascular procedures, and the images were registered with preprocedural MRA for fusion accuracy evaluation. Low-dose noncontrasted 3D angiography of the skull was performed in the other 4 patients, and registered with the MRA. The MRA was overlaid afterwards with 2D live fluoroscopy to guide endovascular procedures.The 3D registration of the MRA and angiography demonstrated a high accuracy for vessel lesion visualization in all 19 patients examined. Moreover, MRA of the intracranial vessels, registered to the noncontrasted 3D angiography in the 4 patients, provided real-time 3D roadmap to successfully guide the endovascular procedures. Radiation dose to patients and contrast medium usage were shown to be significantly reduced.Three-dimensional MRA and angiography fusion can accurately generate cerebral vasculature images to guide endovascular procedures. The use of the fusion technology could enhance clinical workflow while minimizing contrast medium usage and radiation dose, and hence lowering procedure risks and increasing treatment safety.

Figure 1

Three-dimensional (3D) MRA (white) and DSA (yellow) fusion images presented in axial (A), sagittal (B), coronal (C) orientations, and using VRT technique (D). DSA = digital subtracted angiography, MRA = magnetic resonance angiography, VRT = volume-rendering technique.

Figure 2

Three-dimensional (3D) MRA (white) and angiographic (red) fusion results of intracranial arteries: A, R-MCA stenosis; B, R-AICA aneurysm; C, R-ICA aneurysm; D, R-ICA aneurysm; E, L-MCA occlusion. L-MCA = left middle cerebral artery, MRA = magnetic resonance angiography, R-AICA = right anterior inferior cerebella artery, R-ICA = internal carotid artery, R-MCA = right middle cerebral artery, VRT = volume-rendering technique.

Figure 3

Magnetic resonance angiography (MRA) of the intracranial vessel (A); MRA overlaid with live fluoroscopy (B); with the MRA roadmap guidance, the guide wire entered R-VA (C), and approached the aneurysm neck (D); the aneurysm size was measured (E), and coiling was performed (F). Final DSA check of the coiling results in AP (G) and lateral (H) view. AP = anterior-posterior, DSA = digital subtracted angiography.

Figure 4

Preprocedural MRA showed severe BA stenosis (A). MRA was overlaid with live fluoroscopy (B). With 3D MRA roadmap, the guide wire entered left VA and approached the proximal of stenosis (C); the guide wire passed through the stenosis into distal segment (D) and then entered right PCA (E). A balloon was used for predilation of the stenosis (F). A intracranial stent was inserted across the stenosis (G) and expanded by the balloon (H). Final DSA check of the stenting result in AP (I) and lateral (J) view. 3D = 3-dimensional, AP = anterior-posterior, DSA = digital subtracted angiography, MRA = magnetic resonance angiography, PCA = posterior cerebral artery, VA = vertebral artery.