How to differentiate between thrombosed artery vs hypoplastic or absent artery ?
Thrombosis of artery implies to blood clot in lumen and is pathological. Hypoplastic or absent artery is often associated with an alternate or collateral circulation and is a normal anatomical variation.
On MR Angio; non visualisation of an artery implies to either thrombosis or congenital absence. An artery with poor flow related signal can be due to hypoplasia or partial thrombosis.
Most of the time thrombosis of an artery is very obvious where there is associated infarct in corresponding vascular territories. But sometimes it creates diagnostic dilemma solely based on MR Angio when an artery not visualised on Angio and there is no infarct in corresponding vascular territories. We can take help of Ax FLAIR.
In following two cases common finding is absent basilar on MR Angio.
Case 1:
Case 2:
Findings in Case 1:
Basilar not visualised on Angio.
Ax FLAIR shows abnormal signal in pre pontine cistern along the course of basilar implies to thrombosis.
PComs on either side continuing as PCAs, explains sparing of PCA territories from developing an infarct despite of basilar occlusion.
Right vertebral is dominant
Findings in Case 2:
Basilar not visualised on Angio.
Both vertebrals are hypoplastic. Non visualisation of intra cranial portion of left vertebral. PComs on either side continuing as PCAs – fetal PCA.
Ax FLAIR shows no such abnormal signal in pre pontine cistern along the course of basilar.
These finding collectively implies to congenital absence of basilar rather than thrombosis.
Thrombosis of artery implies to blood clot in lumen and is pathological. Hypoplastic or absent artery is often associated with an alternate or collateral circulation and is a normal anatomical variation.
On MR Angio; non visualisation of an artery implies to either thrombosis or congenital absence. An artery with poor flow related signal can be due to hypoplasia or partial thrombosis.
Most of the time thrombosis of an artery is very obvious where there is associated infarct in corresponding vascular territories. But sometimes it creates diagnostic dilemma solely based on MR Angio when an artery not visualised on Angio and there is no infarct in corresponding vascular territories. We can take help of Ax FLAIR.
In following two cases common finding is absent basilar on MR Angio.
Case 1:
Basilar not visualised on Angio.
Ax FLAIR shows abnormal signal in pre pontine cistern along the course of basilar implies to thrombosis.
PComs on either side continuing as PCAs, explains sparing of PCA territories from developing an infarct despite of basilar occlusion.
Right vertebral is dominant
Findings in Case 2:
Basilar not visualised on Angio.
Both vertebrals are hypoplastic. Non visualisation of intra cranial portion of left vertebral. PComs on either side continuing as PCAs – fetal PCA.
Ax FLAIR shows no such abnormal signal in pre pontine cistern along the course of basilar.
These finding collectively implies to congenital absence of basilar rather than thrombosis.
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