Establishing updated diagnostic reference levels for interventional radiology: a national Italian survey...

To update the Italian Diagnostic Reference Levels (NDRLs) in interventional neuroradiology, the Istituto Superiore di Sanità coordinated a working group with consolidated expertise in this field. Establishing DRLs in interventional procedures is particularly challenging due to the complexity influenced by clinical and technical factors. For this reason, aim of this work is to provide DRLs that also take into account procedure complexity.

Data were collected from 20 Italian hospitals concerning cerebral angiography(CA), embolization of cerebral aneurysms (ECA), and Mechanical Thrombectomy (MT). For each procedure, Air-Kerma (K_a,r), Kerma-Area-Product(P_KA), and Fluoroscopy Time(FT) were recorded. Data related to patient age, sex, and radiological equipment were registered. Additionally, for CA number of arteries evaluated, diagnostic priority (elective or emergency), and study type were documented. For ECA, aneurysm status, dome-to-neck ratio, aneurysm size, aneurysm location, and aneurysm morphology were recorded. For MT, collected data included occlusion type, thrombus location, and use of a stent retriever.

P_KA distributions were analysed with non-parametric tests and generalized linear regression models to identify clinical and technical factors affecting dosimetry. Log transformations helped develop a complexity score to classify procedures. The new NDRLs are 191 Gy.cm² for CA (71 Gy.cm² for simple, 117 Gy.cm² for medium, 198 Gy.cm² for complex), 252 Gy.cm² for ECA (136 Gy.cm² for simple, 174 Gy.cm² medium, 268 Gy.cm² complex) and 169 Gy.cm² for MT (71 Gy.cm² for simple, 132 Gy.cm² for medium, 169 Gy.cm² for complex).

This study establishes updated national diagnostic reference levels for interventional neuroradiology in Italy through a comprehensive complexity-stratified approach. The research demonstrates the critical importance of regular DRL updates to reflect evolving practice patterns and technological advances, offering a more nuanced framework that recognizes the inherent variability of neuro interventional procedures across different complexity tiers.