Iodine-based contrast medium-induced Posterior Reversible Encephalopathy Syndrome (PRES) and Contrast-Induced Encephalopathy (CIE): advocating vigilance while challenging the dichotomy

Iodine-based contrast media (ICM) are commonly used in the field of imaging to enhance the visibility of blood vessels and soft tissues during computed tomography (CT) scans or to perform angiographic procedures [1, 2]. These contrast media contain iodine, which strongly absorbs X-rays, helping healthcare professionals to differentiate and highlight structures, and to obtain clearer and more detailed images for accurate diagnosis or treatment of various medical conditions. However, as the use of ICM is commonplace in diagnostic and interventional imaging, it is important to realise that their use might be linked to a rare adverse reaction: Iodine-based contrast medium-induced Posterior Reversible Encephalopathy Syndrome (PRES). This is usually a reversible neurologic condition characterised by subcortical vasogenic brain oedema, predominantly involving the parieto-occipital regions [1, 2]. Multiple hypotheses have been suggested regarding the pathogenesis of PRES. They all entail the activation and harm of the endothelium, as well as the activation of the immune system and the release of cytokines [1]. The most accepted is the “vasogenic theory,” which proposes that rapidly escalating hypertension, coupled with the failure of cerebral autoregulation, leads to the breakdown of the blood–brain barrier and subsequent vasogenic oedema. When blood pressure rises swiftly and significantly, the autoregulatory response becomes inadequate, resulting in hyperperfusion and the leakage of plasma and macromolecules. …