A wedge filter for craniocervical angiography

Pulmonary vein wedge angiography.

Design, implementation and validation of a motorized wedge filter for a telecobalt machine (Bhabhatron-II).

A universal wedge filter of 15W × 20 cm(2) and 60° nominal wedge angle is designed and placed between the collimating jaws and penumbra trimmers inside the treatment head. A pneumatically driven actuating mechanism toggles the wedge between the wedge IN position and wedge OUT position. The effective wedge angles were determined using an analytical formula. An accumulated wedge profile at a dept...

2D Wedge Filter Design and Applications in Oriented Line Extraction

An analytical design method is proposed for two-dimensional recursive zero-phase wedge filters. It relies on a frequency mapping applied to a 1D IIR low-pass maximally-flat prototype filter of a specified shape. The design is presented in two versions, one entirely analytical, based on the bilinear transform, and another involving a numerical approximation step. This paper focuses on the design...

Characterization of Craniocervical Artery Dissection by Simultaneous MR Noncontrast Angiography and Intraplaque Hemorrhage Imaging at 3T.

BACKGROUND AND PURPOSE Craniocervical artery dissection is the most common cause of ischemic stroke identified in young adults. For the diagnosis of craniocervical artery dissection, multisequence MR imaging is recommended but is time-consuming. Recently, investigators proposed a simultaneous noncontrast angiography and intraplaque hemorrhage imaging technique allowing simultaneous noncontrast ...

Craniocervical pneumatization.

Craniocervical bony pneumatization is a rare finding, with limited numbers of cases reported in the literature. It is thought to be linked to Eustachian tube dysfunction and a ball valve mechanism, and has a link with recurrent Valsalva maneuvers. We report a case of pneumatization of the occiput, atlas (C1) and axis (C2) in a patient with extensive ENT (Ear, Nose and Throat) surgical history w...