Scout View
1. A good angiographic A-P projection superimposes the orbital roof on the top of the petrous pyramid. Careful coning adds to the quality and lack of scatter on this film, both of which improve the sharpness and definition of the vessel walls.
2. Line indicates the lateral border of the zygomatic process of the frontal bone. Similar line on the other side is present. The half way distance between these lines measures the midline in the anterior cranial fossa. Even if the patient is slightly rotated measurement between these two points will correct for any rotation and this midline is used to check the midline position of the patient's anterior cerebral arteries. The halfway distance between the two outer tables in the parietal region is used to check the midline position for the internal cerebral vein.
3. The inferior surface of the anterior clinoid. Note on the next film how the supraclinoid portion of the internal carotid artery comes out underneath this part of the anterior clinoid.
Early arterial phase (1.5 seconds post injection of contrast)
1. Internal maxillary branch of the external carotid artery
2. Occipital branch of the external carotid artery
3. Cervical portion of the internal carotid artery
4. Petrous portion of the internal carotid artery, rests in the carotid canal in the medial portion of the petrous pyramid
5. Parasellar portion of the carotid artery, which is extradural and lies on the lateral surface of the sphenoid sinus and sella.
6. Most posterior portion of the internal carotid artery as it begins to course forward adjacent to the sella
7. Anterior genu of the internal carotid artery, just underneath the anterior clinoid process
8. Supraclinoid portion of the internal carotid artery, now intradural and intra-arachnoid
9. Ophthalmic artery, branch of the internal carotid artery
10. Anterior choroidal artery, rests on the medial surface of the uncal portion of the hippocampal gyrus of the temporal lobe. Medial displacement of the temporal lobe can push this artery towards the midline and indicates brain stem compression and uncal herniation.
11. Anterior cerebral artery, horizontal portion
12. Recurrent artery of Heubner. This normal variant courses laterally to supply the medial portion of the lenticulostriate artery distribution which enters the brain through the anterior perforated substance.
13. Frontal polar branch of the anterior cerebral artery
14. Anterior communicating artery
15. Vertical portion of the anterior cerebral artery
16. Pericallosal branch of the anterior cerebral artery. It is the position of this branch which is measured for midline displacement.
17. Callosal marginal branch of the anterior cerebral artery. This frequently rests off the midline because it is in the cingulate sulcus.
18. Distal and posterior branches of the pericallosal and callosal marginal branches of the anterior cerebral artery.
Early arterial phase (2 seconds post injection)
1. Middle cerebral artery
2. Lenticulostriate group of arteries which originate from the horizontal portion of the middle cerebral artery
3. Orbital frontal branch of the middle cerebral artery
4. Normal trifurcation of the middle cerebral artery
5. This is the vertical portion of the sylvian branches of the middle cerebral artery which rests against the surface of the insula.
6. These lower branches which come out laterally and go over the temporal and frontal operculum are coming out the anterior portion of the sylvian fissure.
7. Region of the sylvian point which should be between 40 and 45 mm from the inner table. This point measures the position of the most posterior branch of the middle cerebral artery group which is still deep in the sylvian fissure.
8. These horizontal branches are coming out of the sylvian fissure in the posterior temporoparietal region.
9. Note how the distal middle cerebral artery branches come out to the inner table. Separation of these branches from the inner table is seen in cases such as subdural hematoma.
Capillary phase (3.5 seconds post injection)
1. The relative whiteness in this area compared with the adjacent part of the left cerebral hemisphere indicates the contrast in the capillaries of the brain substance in the anterior cerebral artery distribution.
2. Increased density in this region shows capillary filling in the areas supplied by the middle cerebral artery.
3. Note the absence of contrast in the middle cerebral artery which is now filled with unopacified blood.
4. The proximal portion of the anterior cerebral artery also is filled with unopacified blood.
5. Distal anterior cerebral artery branch still has sone contrast within it.
6. Distal middle cerebral artery branches still contain some contrast.
7. The area of the lateral ventricle (shaped like a half of a heart) shows a relative absence of contrast. The size of the ventricle can frequently be estimated on the capillary phase.
Early venous phase (8.5 seconds post injection)
Both the veins of the deep and superficial venous system are filled.
1. Internal cerebral vein. As this is a paired structure, the medial surface of this vein should rest on the midline.
2. Thalamostriate vein
3. Basilar vein of Rosenthal. This rests on the lateral surface of the brain stem in the region of the mesencephalon.
4. Peduncular vein. This rests on the anterior surface of the right cerebral peduncle.
5. Deep middle cerebral vein
6. Anterior cerebral vein
7. Inferior ventricular vein. This faintly visualized vein defines the medial superior wall of the posterior part of the temporal horn of the lateral ventricles.
8. Superior petrosal sinus
9. A parietal superficial cortical vein
10. A frontal opercular superficial cortical vein. Note how this vein is adjacent to the inner table. A subdural hematoma would displace this vein medially.
11. Superior sagittal sinus
Late venous phase (9.5 seconds post injection)
Most of the superficial cortical veins have washed out leaving the deep cerebral veins better visualized.
1. Medial surface of the internal cerebral vein
2. Direct lateral vein. This vein rests on the floor of the body of the lateral ventricle and enters the internal cerebral vein approximately one and one-half centimeters posterior to the foramen of Monro.
3. Thalamostriate vein
4. Superior sagittal sinus
5. Transverse sinus
6. Sigmoid sinus. This portion of the sigmoid sinus courses inferiorly and exits the skull through the jugular foramen at which point it becomes the internal jugular vein.