Lateral Scout View
1. Image is centered just inferior to the calcified pineal gland. The anterior portion of the skull is frequently coned off as the area of interest on the vertebral injection is the posterior fossa and the occipital, as well as the posterior parietal lobes.
2. Accuracy of the lateral projection is judged by superimposition of the two mandibular condyles.
3. Note the position of the posterior rim of the foramen magnum.
4. At least up to this portion of the skull should be visualized as parieto-occipital branches of the posterior cerebral artery will be opacified in this area.
Early Arterial Phase (1 sec post injection)
1. Both vertebral arteries are filled, the right and smaller vertebral artery being filled by reflux from the left injection.
2. Muscular branches, vertebral artery
3. Basilar artery
4. Posterior communicating artery
5. Minimal reflux through the circle of Willis into the anterior cerebral artery
6. Posterior inferior cerebellar artery (PICA); A: premedullary portion, B: lateral medullary portion, C: postmedullary portion, D: Choroidal point, E: Choroidal vessels, F: inferior vermian branch
7. Anterior inferior cerebellar artery (AICA); A: Loop of AICA near internal auditory meatus, B: inferior cerebellar hemispheric branches
8. Superior cerebellar arteries
9. Posterior cerebral arteries
10. Calcarine branch, posterior cerebral artery
11. Parieto-occipital branch posterior cerebral artery
Early Arterial Phase (1.5 sec post injection)
1. Superior tonsillar branch, PICA
2. Inferior hemispheric branches, distal PICA
3. Hemispheric branches, superior cerebellar artery
4. Anterior thalamoperforate branch, posterior communicating artery
5. Posterior thalamoperforate branches of the posterior cerebral artery. These enter the base of the brain through the posterior perforated substance in the inter-peduncular fossa.
6. Deep perforating thalamic branches of the posterior cerebral artery
7. Medial posterior choroidal branches of the posterior cerebral arteries. These arteries lie just behind the pineal gland in the midline and course forward in the roof of the third ventricle to the region of the foramen of Monro.
8. Lateral posterior choroidal arteries. These lie on the posterior surface of the thalamus, otherwise called the pulvinar.
9. Posterior pericallosal branch of the posterior cerebral artery.
Capillary Phase (five seconds post injection)
1. The light area encompassed by the two lines is the thalamic blush, as most of the supply to the thalamus is through branches of the posterior cerebral artery.
2. Note that most of the contrast has been washed out of the basilar artery which is now filling with unopacified blood.
3. Distal branches of the superior cerebellar artery still have some contrast within them.
4. Distal branches of the posterior inferior cerebellar artery still contain some contrast. The remaining lightness in the posterior fossa is secondary to the contrast which is now in the capillaries of the cerebellum.
Mid-Venous Phase (eight seconds post injection)
1. Inferior vermian vein. This will drain either into the posterior portion of the straight sinus or into the medial portion of the transverses sinuses.
2. Inferior cerebellar hemispheric vein. These veins drain into the more lateral portion of the transverse sinus.
3. Transverse sinus
4. Thalamostriate vein
5. Internal cerebral vein
6. Basilar vein of Rosenthal
7. Inferior ventricular vein. Note how this vein receives a branch from the lateral portion of the atrium of the lateral ventricle. This vein drains into the basilar vein of Rosenthal farther anteriorly.
8. Anastomotic lateral mesencephalic vein. This is a congenital variant and joins, in this patient, the basilar vein of Rosenthal to the pontomesencephalic system of veins.
9. Pontomesencephalic veins
10. Lateral mesencephalic vein
11. Petrosal vein
12. Precentral cerebellar vein
13. Colliculocentral point. This is a reliable angiographic point measured at the point where the precentral cerebellar vein courses more posteriorly. It is resting on the surface of the anterior medullary velum just above the lingula of the cerebellum. This point should be very close to a perpendicular line drawn from the half way point of a line which goes between the tuberculum sellae and the torcula.
14. Superior vermian vein
15. Great vein of Galen
16. Straight sinus. This sinus rests in the dural tentorium at its apex. The superior surface of the cerebellum is just underneath this part of the tentorium and this is why the superior cerebellar arteries in the midline project above some of the more lateral branches of the posterior cerebral artery.