Towards standardised contrast injection protocols in diagnostic cerebral angiography for unruptured aneurysm...

Diagnostic cerebral angiography remains the gold standard for the evaluation of intracranial aneurysms, but current practices regarding iodinated contrast media (ICM) injection are highly variable. No standardised recommendations exist, affecting patient safety, comfort, and diagnostic reliability. This review summarises current practices and highlight the potential of applying the ALADA - As Low As Diagnostically Acceptable - principle to ICM injections, emphasising the role of the interventional neuroradiologist-radiographer team in promoting safe, patient-centred, and robust procedures.

Injection parameters reported in the literature presented significant heterogeneity. In 2D DSA of the internal carotid artery (ICA), volumes range from 5.0 to 10.0 mL at 3.0-7.0 mL/s. For the vertebral artery (VA), volumes range from 4.5 to 8.0 mL with flow rates between 2.5 and 5.0 mL/s. In 3D-RA, acquisitions are conducted using injection volumes between 10.0 and 36.0 mL at 1.5-5.0 mL/s for ICA, and 10.0-24.0 mL at 2.0-5.0 mL/s for VA. These variations highlight the large potential for rational optimisation, to reduce ICM exposure, and consequently the risk of contrast-induced nephropathy and adverse reactions, while improving patient tolerance and maintaining diagnostic reliability.

Application of the ALADA principle to ICM injections in cerebral angiography is currently unexplored, but it clearly offers a path towards safer, patient-centred and evidence-based practice.

Developing harmonised, quantitative guidelines for ICM injection in cerebral angiography would support protocol standardisation, enhance patient safety, and strengthen the role of radiographers in implementing optimised practices.