Answer for CoW 12 Nov 2017
ICA AGENESIS
Findings
MRI showed non visualisation of cervical , petrous , carotid, cavernous , supra clinoid segments of right internal carotid artery Right Middle cerebral artery is supplied thro the hypertrophied Posterior communicating artery form the basilar Right Anterior cerebral artery is supplied thro the patent anterior communicating artery CT axial sections shows hypoplastic right carotid canal.
Discussion
Congenital absence of the internal carotid artery has a prevalence of 0.01% . CT of the skull base and CT angiography in such cases demonstrate an absence of the carotid canal . The anomaly may be unilateral or, more rarely, bilateral . The recognition of internal carotid artery agenesis is important, especially in patients with cerebral thromboembolic disease due to atherosclerosis of the vertebrobasilar system There is also a strong association between internal carotid artery agenesis and the development of intracranial aneurysms Collateral pathways Belong into three main types: collateral flow through the circle of Willis (most frequent), collateral flow via persistent fetal circulation, and reconstitution of the ICA through skull base collaterals from the ECA.
Findings
MRI showed non visualisation of cervical , petrous , carotid, cavernous , supra clinoid segments of right internal carotid artery Right Middle cerebral artery is supplied thro the hypertrophied Posterior communicating artery form the basilar Right Anterior cerebral artery is supplied thro the patent anterior communicating artery CT axial sections shows hypoplastic right carotid canal.
Discussion
Congenital absence of the internal carotid artery has a prevalence of 0.01% . CT of the skull base and CT angiography in such cases demonstrate an absence of the carotid canal . The anomaly may be unilateral or, more rarely, bilateral . The recognition of internal carotid artery agenesis is important, especially in patients with cerebral thromboembolic disease due to atherosclerosis of the vertebrobasilar system There is also a strong association between internal carotid artery agenesis and the development of intracranial aneurysms Collateral pathways Belong into three main types: collateral flow through the circle of Willis (most frequent), collateral flow via persistent fetal circulation, and reconstitution of the ICA through skull base collaterals from the ECA.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!