1978, British Journal of Radiology, 51, 5-10
JANUARY
1978
Pseudo-occlusion of the internal carotid artery By P. Macpherson, F.R.C.R., D.T.C.D. Institute of Neurological Sciences, Southern General Hospital, Glasgow G51 4TF {Received May, 1977 and in revisedform June, 1977) ABSTRACT
In a ten-year period, 31 cases of pseudo-occlusion of the internal carotid artery were seen; 42 carotid angiograms were available for analysis. On the first film of the series the contrast came to a tapered end in the cervical portion of the internal carotid artery in 16; extended to the carotid canal in 11 ; to the siphon in eight and to proximal intracranial vessels in seven. In 17 patients later films showed advance of the contrast. In four it did not get beyond the foramen lacerum; in eight it reached the siphon and in five the proximal intracranial vessels. Eight angiograms of patients with intracranial occlusion were examined and showed identical appearances. Contrast opacified the middle menigeal artery in 29 of the 31 pseudo-occlusion cases. The circulation time was slow in 28. The circulation times through the middle menigeal artery were more or less identical with those in the superficial temporal arteries and unaffected by systolic blood pressure. Twenty-three of the pseudo-occlusion cases were being ventilated and 25 had fixed dilated pupils. The commonest aetiological factors were trauma, haematoma due to ruptured aneurysm and primary tumour. In the occlusion group no case was being ventilated and only one had fixed dilated pupils. Course of action on finding the appearances of pseudo-occlusion is suggested.
The term pseudo-occlusion was proposed by Newton and Couch (1960) to describe an appearance first reported by Riishede and Ethelberg (1953) in five moribund patients with acutely raised intracranial pressure. Contrast does not usually progress beyond the carotid siphon and any filling of intracranial
vessels that occurs is very slow and incomplete. Davies and Sutton (1967) reported five cases seen over the preceding 12 years to add the to 25 cases which they had culled from the literature. With the advent of EMI scanning, angiography is likely to be used less frequently in conditions associated with high intracranial pressure. It seemed appropriate, therefore, to review the angiograms performed in this Institute during the ten-year period 1966-75, as such numbers will not likely be available in the future. An additional reason is that there have been recommendations from some countries that this sign should be sought as confirmatory evidence of brain death. METHODS
Contrast medium (10 ml) was injected by hand through a 17-gauge cannula into the common carotid artery. An automatic timing device gave 1.25 sec between each exposure. A non-screen film of the carotid bifurcation in the neck, taken as a routine, made it possible to verify that there was no technical reason for the appearances. RESULTS
In the ten-year period under review there were 16 cases in which the contrast medium did not go
TABLE I GROUP TO BE DISCUSSED
Cases
Pseudoocclusion
Contrast did not extend beyond siphon
Contrast slightly beyond siphon Occlusion
Group I Arteries patent at autopsy
16
Bilateral examinations
Unilat. exam.
Bilat. pseudo-occl. 6
Unilat. pseudo-occl. 4
7*
Total car. angios for for analysis
23
Group II no autopsy
6
2
2
2
8
Group III Arteries patent at autopsy
9
2
4
3
11
31
10
10
12
42
7
1
3
3
8
Total Group IV
•Including a repeat of a bilateral examination.
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Occlusion
Pseudoocclusion
ase.
0 16
Group III 11
Total 42 4
2
14
Tapered end in neck
2
11
2
3
6
Carotid canal
2
8
2
3
3
Siphon
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JANUARY
1978
Pseudo-occlusion of the internal carotid artery By P. Macpherson, F.R.C.R., D.T.C.D. Institute of Neurological Sciences, Southern General Hospital, Glasgow G51 4TF {Received May, 1977 and in revisedform June, 1977) ABSTRACT
In a ten-year period, 31 cases of pseudo-occlusion of the internal carotid artery were seen; 42 carotid angiograms were available for analysis. On the first film of the series the contrast came to a tapered end in the cervical portion of the internal carotid artery in 16; extended to the carotid canal in 11 ; to the siphon in eight and to proximal intracranial vessels in seven. In 17 patients later films showed advance of the contrast. In four it did not get beyond the foramen lacerum; in eight it reached the siphon and in five the proximal intracranial vessels. Eight angiograms of patients with intracranial occlusion were examined and showed identical appearances. Contrast opacified the middle menigeal artery in 29 of the 31 pseudo-occlusion cases. The circulation time was slow in 28. The circulation times through the middle menigeal artery were more or less identical with those in the superficial temporal arteries and unaffected by systolic blood pressure. Twenty-three of the pseudo-occlusion cases were being ventilated and 25 had fixed dilated pupils. The commonest aetiological factors were trauma, haematoma due to ruptured aneurysm and primary tumour. In the occlusion group no case was being ventilated and only one had fixed dilated pupils. Course of action on finding the appearances of pseudo-occlusion is suggested.
The term pseudo-occlusion was proposed by Newton and Couch (1960) to describe an appearance first reported by Riishede and Ethelberg (1953) in five moribund patients with acutely raised intracranial pressure. Contrast does not usually progress beyond the carotid siphon and any filling of intracranial
vessels that occurs is very slow and incomplete. Davies and Sutton (1967) reported five cases seen over the preceding 12 years to add the to 25 cases which they had culled from the literature. With the advent of EMI scanning, angiography is likely to be used less frequently in conditions associated with high intracranial pressure. It seemed appropriate, therefore, to review the angiograms performed in this Institute during the ten-year period 1966-75, as such numbers will not likely be available in the future. An additional reason is that there have been recommendations from some countries that this sign should be sought as confirmatory evidence of brain death. METHODS
Contrast medium (10 ml) was injected by hand through a 17-gauge cannula into the common carotid artery. An automatic timing device gave 1.25 sec between each exposure. A non-screen film of the carotid bifurcation in the neck, taken as a routine, made it possible to verify that there was no technical reason for the appearances. RESULTS
In the ten-year period under review there were 16 cases in which the contrast medium did not go
TABLE I GROUP TO BE DISCUSSED
Cases
Pseudoocclusion
Contrast did not extend beyond siphon
Contrast slightly beyond siphon Occlusion
Group I Arteries patent at autopsy
16
Bilateral examinations
Unilat. exam.
Bilat. pseudo-occl. 6
Unilat. pseudo-occl. 4
7*
Total car. angios for for analysis
23
Group II no autopsy
6
2
2
2
8
Group III Arteries patent at autopsy
9
2
4
3
11
31
10
10
12
42
7
1
3
3
8
Total Group IV
•Including a repeat of a bilateral examination.
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Occlusion
Pseudoocclusion
ase.
0 16
Group III 11
Total 42 4
2
14
Tapered end in neck
2
11
2
3
6
Carotid canal
2
8
2
3
3
Siphon
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