Cerebral angiographic projections

Discussion:

Intracranial selective cerebral angiographic projections

Baseline patient positioning

  • Patient supine, head supported in radiolucent head holder or curved sponge
  • Strap across patient's head to minimize movement
  • Head positioned without rotation
  • Head tilt (radiographic baseline) determined by patient comfort
    • Patient should not be forced into an uncomfortable head tilt
    • Adjustments made for head tilt by cranio-caudal C-arm angulation

Internal carotid artery - posteroanterior (PA) projection

Internal carotid artery - lateral projection

  • Right lateral where possible
    • Minimize dose to operator (if standing in room during acquisitions)
  • Include entire skull

Internal carotid artery - transorbital oblique projection

  • Petrous ridge positioned on infra-orbital margin
  • Ipsilateral obliquity 30 degrees
  • Collimation - generally include entire skull vault; however, magnification can be employed if indication is specifically for intracranial aneurysm
  • Center on lateral edge of orbit

Internal carotid artery - reverse trans-orbital oblique projection

  • Petrous ridge positioned on infraorbital margin
  • Contralateral obliquity of 30 degrees
  • Collimation - generally include entire skull vault; however, magnification can be employed if indication is for aneurysm
  • Center to include lateral edge (side of interest) of skull

Internal carotid artery - cross compression projection

  • Petrous ridge positioned on infra-orbital margin
  • No obliquity
  • Collimate image on top and bottom
  • Image must be annotated with cross compression (or x-compression)

Vertebral artery - posteroanterior (PA) projection

  • Petrous ridge positioned on supra-orbital margin
  • Collimation to include lambdoid suture at top and approximately 5 cm below the infraorbital margin (for inclusion of possible extracranial PICA)
  • Technique variations -
    • Increase cranial angle (Townes) to demonstrate Posterior cerebral arteries
    • Decrease angle (Waters) to best demonstrate basilar artery)

Vertebral artery - lateral projection

  • Compared to lateral ICA projection
    • Increase magnification
    • Posterior border of collimation to include skull vault
    • Inferior border of collimation to include posterior arch of C1 (inclusion of possible extracranial PICA)
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