Vitrea Proficiency

• Vitrea is a software program that works with our PACS and is used for 3D analysis and perfusion imaging

• Step by step instructions with screenshots can be found below

VITREA

• • Perfusion 

  • MIPs 

• Obliques

Perfusion

• This technique is used to process a CT angiography study of the brain to identify a region of the brain after a stroke where intravenous contrast enters (brain is still viable), but it is flowing slowly (long transit time)

• Depending on the size of this brain region at risk (the penumbra), the patient may get an neurointerventional procedure or tPA

• You use Vitrea to create three images from the CT angiography study: 

  • Cerebral blood flow (CBF)

  • Cerebral blood volume (CBV)

  • Mean transit time (MTT)

• Related by the equation:

  • CBF =CBV/MTT

• Infarcted tissue will have: 

  • Decreased CBF

  • Decreased CBV

  • Elevated MTT

• Tissue at risk of infarction: 

  • Decreased CBF

  • Normal or elevated CBV secondary to activation of cerebral autoregulatory mechanisms (oxygen starved vessels autoregulate & dilate to compensate for decreased oxygen)

  • Elevated MTT

MIPs 

• Maximum intensity projection (MIP) is a technique for creating an image from the data from the scanner

• In certain studies, the technicians do this routinely on the 64 slice scanner software and send the images to PACS

• If the studies are done on another scanner, we need to do this on our own in Vitrea

•  In a normal CT image, you look at a slice of the body and all the structures with their associated Hounsfield units are displayed

• In MIP images, you look at a slab of the body (a bunch of slices put together) from a certain angle, and the structures with the highest Hounsfield attenuation in that volume are displayed, as you would see them from your certain angle

• This is mostly used to view vessels which contain intravenous contrast of higher attenuation than the surrounding tissues

• Unfortunately, in some body parts where bone and vessels are very close together, such as the skull base and neck, the bones get included in the MIP images (because they are just as bright or brighter than the vessels with contrast)

Obliques

• You can use this to change the viewing plane to make the anatomy “line up” on CT studies

• For example, if patient’s head was tilted in the scanner, you can change the plane to have the left and right sides of the brain anatomically line up

• Also, if a patient’s cervical spine is really lordotic, you can change the viewing plane to see a certain vertebral body or section of the spine in its entirety in one image