Glossary

Dural Sinus Malformation.  A congenital malformation of a dural venous sinus, typically found in the posterior fossa (Posterior sagittal sinus, transverse sinus or sigmoid sinus) and typically massive in size.

Congenital malformations of dural venous sinuses, typically found in the posterior fossa (Posterior sagittal sinus, transverse sinus or sigmoid sinus) and typically massive in size.

Diffusion Tensor Imaging – A MRI technique using a variant of diffusion weighted imaging to analyze white matter structure and integrity. Diffusion Tractography refers to a subsequent post-acquisitional processing that identifies white matter tracts.

Diffusion Tensor Imaging – A special type of diffusion weighted imaging (DWI) that is used to image white matter tracts (nerve axon tracts) within the central nervous system.  White matter tracts’ axons have physical properties that are anisotropic (directionally dependent) and this causes variation in the rate of water molecule migration in a magnetic field depending on direction.  DTI measures this variability to generate images or maps of white fiber tract orientation within the CNS.

Deep Tendon Reflex(s): Also referred to as ‘muscle stretch reflex.  An examination of the sensitivity of muscles to a sensory input.  The tendon of a muscle is tapped by an examination hammer (tendon stretched), the muscle senses the stretch and sends a signal to the spinal cord, the spinal cord reacts to this signal (afferent sensory signal or nerve potential) and causes a signal (efferent motor signal or nerve potential) to be sent back to the muscle causing it to contract (hence causing movement such as a leg jerking in response to tapping the knee tendon).

A technique for increasing imaging contrast between dissimilar tissues.  Biological tissues attenuate X ray beams to differing extents depending on (a) the nature of the tissue and (b) the energy of the X ray beam. First generation CAT scanners used X ray at a single energy level. By using two X ray sources, at differing energy levels (dual energy technique), contrast definition between tissues and therefore image resolution can be improved.

A condition where abnormal cranial nerve development results in a limited ability to move the eyes outward. There is also abnormalities in the bones of the hands or absent thumbs, extra thumbs and absent of the bones of the forearm to a varying degree.

Refers to the repair or expansion of the dura (the outer covering of the central nervous system).  In the case of its referring to expansion, this can be accomplished using an artificial substance or tissue obtained from elsewhere in the patient’s body that is “grafted” into the opening of the dura.

Developmental venous anomaly (aka – cerebral venous angioma) – a developmental anomaly consisting of a collection of veins draining into a single larger collecting vein, which in turn drains into either a dural sinus or into a deep ependymal vein. The appearance has also been likened to a palm tree. They are the most common cerebral vascular malformation (range 50-63%).

Deep vein thrombosis – refers to clotting within the deep veins of the body, typically those of the extremities and in particular the legs.