Cone Beam How To Do It Step by Step Philips

The material / cases in this section were collected and organized by Dr. Guglielmo Pero. A neuroangio team effort!

Cone Beam How To Do It Step By Step, Philips Azurion

With Philips Azurion, you can do three main Cone Beam acquisitions:

  1. A whole-head (large field of view) acquisition, made for brain visualization or for the detection of hemorrhagic complications (the so-called XperCT). The acquisition lasts 10 or 20 seconds (depending on the framerate), with 622 views, all with identical image quality; the primary reconstruction matrix is 2963. It is very advantageous for AVM targeting for the Gamma Knife. New systems allow for the acquisition with “butterfly” movement to improve image quality.
  2. The classical 3D acquisition is mainly used for pre-embolization aneurysm studies; it is also helpful to study small AVMs. It can be acquired with all available fields of view and acquires 122 views in 5 seconds; the primary reconstruction matrix is 3843. Moreover, you can perform a non-injected acquisition to subtract and improve the quality of the injected 3D reconstructions.
  3. The High-Resolution Cone Beam CT (the so-called Vaso-CT, corresponding to the Siemens Dyna-CT). It acquires 622 views with a 22 cm field of view in 20 seconds; the primary reconstruction matrix is 3843.

Because of the long acquisition time, the Vaso-CT cannot be purely arterial or venous, and we find it more helpful to correlate the 2D series with the Vaso-CT reconstructions.

Vaso-CT acquisition and reconstruction

The principles to obtain excellent Vaso-CT images are the same as those reported in Practice — How To Get Excellent Images Brain and Practice– How to get excellent Images Spine.

Immobile patients (preferably breath-holding in spinal cases and in large patients with wide breathing excursions) and complete arterial filling are mandatory for obtaining high-quality HR-CBCT reconstructions.

Possible applications of HR-CBCT:

  • Anatomy evaluation before treating an aneurysm.
  • After intravascular or intrasaccular device positioning.
  • Dural arteriovenous fistula or AVM evaluation, injecting from the internal/external carotid or vertebral artery.
  • Dural arteriovenous fistula or AVM evaluation, selectively injecting from microcatheters.
  • Small artery evaluation
  • Fusion of post-embolization cast (EvOH, cyanoacrylate) with pre-embo images

Fusion of two datasets, obtained injecting different vessels, improves a lot the understanding of AVMs and DAVFs. For examples of all types of fusions, go here

The Xper-CT can be acquired with or without the frame. It must be done during the selective injection of the internal or external carotid artery or the vertebral artery. Remember, if you acquire it with the GK frame, use the CT-specific localizer (you will change the localizer after the 2D angio, and if you need more than one vessel dataset, you must do this changing more than once). We suggest a 10-second acquisition, injecting 20 ml of 50% 300 mg/ml iodine contrast at 2 ml/sec, starting the injection 5 seconds before the acquisition.

The first thing to do is to create a new reconstruction: 100% cube, stent kernel, and high resolution. It enhances definition and sharpens AVM vessels.

Before importing (or sending) the series to the GammaPlan workstation, you must change the modality DICOM tag from XA (original) to CT using a different software (like Horos for MAC), and then GammaPlan will see it as a standard CT. Be aware that most of the PACS systems do not accept this change, and you must send the images directly from the Horos system.

We can use these datasets directly with the GammaPlan software to target the AVM (slides 3-10).

Two datasets can be fused in the 3D reconstruction workstation to produce red and blue images showing which feeders supply each part of the AVM. Unfortunately, we cannot export the fused dataset for use in the Gamma Plan; we can only export it as videos or single screenshots (slides 11-18).

BELOW ARE MULTIPLE EXAPLES OF HOW TO CREATE AND USE CONE BEAM IN VARIOUS CLINICAL SETTINGS

AVM Gamma Knife Targeting and 6D Fusions

Complex Aneurysms — Flow Diversion and Stenting — complex instructive cases

Giant Fusiform MCA Aneurysm Bypass and Trapping

Aneurysm Artisse Cases — how to obtain and optimize MIP and VR images