Unintended intra-arterial injection of contrast of an intracranial CT angiography.

Computed tomography angiography (CTA) is widely used to evaluate intracranial vascular disease. We report a case of intracranial CTA with unintended intra-arterial (IA) injection of contrast due to IA placement of an intravenous cannula, which results in a selective left vertebral artery IA CTA. Knowledge of anatomy is essential in analyzing the whole study and identifying the error. In clinical practice, it is important to avoid and recognize a wrongly placed intravenous cannula. And bolus tracking protocol might play a role as a gatekeeper.