Assessment of the cerebral venous system from the transcondylar ultrasound window using virtual navigator technology and MRI

Abstract

The Chronic Cerebro-Spinal Venous Insufficiency, recently described as a possible role in Multiple Sclerosis pathogenesis, is diagnosed and classified with Echo Color Doppler (ECD) examination of the extra- and intra-cranial veins. As to the intracranial examination, the presence of reflux in the deep cerebral veins (DCVs) or in the dural sinuses is inspected, with a new insonation approach, i.e. the transcondylar window. This work describes a procedure for the co-registration of anatomical Proton Density-weighted Magnetic Resonance Images (MRI) with the intracranial ECD obtained through the transcondylar window. The procedure, preliminarily tested on 10 volunteers, allowed to assess what are the DCVs visible from this new insonation approach and their position relative to the surrounding brain tissues.

Comparison of brain vessel imaging from transtemporal and transcondylar approaches using contrast-enhanced transcranial color-coded duplex sonography and Virtual Navigator

“…The accuracy of the system measured using a registration pen was excellent (< 1 mm) with the root mean square error < 0.5 cm. These results are in accord with those of previous studies 7,8,13 . The improvement of the blood flow detection from intracranial arteries, veins and sinuses can be achieved by the echo-contrast agent application.…”

“…10 ). The venous blood flow is slow (0.10-0.40 m/s) and it is affected by the respiratory phase 8 . Moreover, the cavernous sinus is located close to the nasal space, and the respiration air flow may imitate the venous blood flow.…”

“…Moreover, the cavernous sinus is located close to the nasal space, and the respiration air flow may imitate the venous blood flow. Fusion imaging technology is able to help with the correct detection of venous blood flow due to real-time fusion of MRI and TCCS images, where the venous system was imaged using brain MRI and venous blood flow was encoded to the MRI image using the color Doppler mode 8,11,12 . The accuracy of the system measured using a registration pen was excellent (< 1 mm) with the root mean square error < 0.5 cm.…”

“…The Virtual Navigator procedures were implemented using an electromagnetic tracking system, composed of a transmitter and a small receiver, mounted on the US probe. The transmitter position, which is considered the origin of the reference system, was fixed through a support, and the receiver provided the position and orientation of the US probe in relation to the transmitter 8 . Examinations were carried out by a well-trained sonographer (with 16 years of TCCS experience) for the venous intracranial evaluations with TCCS and CE-TCCS from transtemporal and transcondylar approaches.…”

Transcranial color coded sonography: advanced approach using ultrasound fusion imaging

“…Two authors particularly addressed the specific issue of sonographic identification of intracranial veins [7,8] using an unconventional transcondylar ultrasound bone window. One further publication of the former group has since reported on a specific 3D-panoramic ultrasound approach in three healthy volunteers [9].…”