Unilateral dysgenesis of the internal carotid artery: spectrum of imaging findings.
OBJECTIVE
Dysgenesis of the internal carotid artery (ICA) is a broad term comprising hypoplasia, aplasia and agenesis of the vessel. It is a rare anomaly, often clinically silent, that can be confidently diagnosed by means of noninvasive imaging methods.


METHODS
After a review of teaching files, 7 patients with unilateral carotid dysgenesis were found, 2 with agenesis of the ICA, 3 with carotid aplasia, and 2 with hypoplasia of the vessel. Computed tomography (CT) and magnetic resonance angiography (MRA) of the brain were performed in all patients, with a complete magnetic resonance of the brain in 3 of them, a CT angiography of the brain in one, and MRA of the cervical arteries in 3.


RESULTS
The fetal pattern of arterial circulation was found in 3 patients with agenesis/aplasia of the ICA and the adult pattern was found in 2 patients, being the brain circulation of normal pattern in the patients with hypoplasia of the ICA. Two patients presented signs of reduced flow to the brain hemisphere ipsilateral to the carotid dysgenesis; one of them with an old homolateral brain infarction.


CONCLUSIONS
Far from being just an anatomic curiosity, the dysgenesis of the ICA may have serious consequences if not recognized prior to endarterectomies, carotid ligation or transsphenoidal surgery. As much as one-third of these patients will have intracranial aneurysms as well. The imaging methods, instead being mutually exclusive, are complementary in the evaluation of carotid dysgenesis.
Magnetic Resonance Department, Clínica Radiológica Vila Rica, Brasília, Brazil.
José Luiz Furtado
JL
de Mendonça
Sergio Lopes
SL
Viana
Flávia Mendes Oliveira
FM
Freitas
Valter de Lima
Vde L
Matos
Maria Angélica de Carvalho Barbosa
MA
Viana
Renato
R
Faria e Silva
Luiz Augusto Nardelli
LA
Quaglia
Jozephina Gonçalves
JG
Guerra
D000293:Adolescent; D000368:Aged; D002340:Carotid Artery Diseases / Q000175:diagnosis*; D002343:Carotid Artery, Internal / Q000002:abnormalities* / Q000000981:diagnostic imaging* / Q000473:pathology; D002560:Cerebrovascular Circulation; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D035583:Rare Diseases; D014057:Tomography, X-Ray Computed / Q000379:methods*