Editorial [Hot Topic: Contrast Media: Induction of Side Effects and Pharmacological Treatment (Guest Editors: Ingrid Bohm & Hans H. Schild)]

Contrast medium (CM)-enhanced X-ray examinations are indispensable in clinical medicine. This is reflected by approximately 40-50 million CM-administrations per year worldwide. This number will probably increase due to increasing prevalence/incidence rates of malignant and cardio-vascular diseases, the need to monitor new therapeutic approaches (e.g. gene therapy), and last but not least, due to new technical approaches for early detection of disease. It is known that CM can induce allergic/pseudoallergic and inflammatory side effects, cell damage such as apoptosis, and cardio-vascular reactions. The cell-biologic, immunologic and allergic basis of these reactions are investigated world-wide. Knowing the molecular-biologic background may serve to explain the rationale for side effect prevention and treatment. The review of Dr. E.A. Coors and Dr. Ingrid Böhm describes "Histamine-dependent and -independent hypersensitivity reactions to contrast media: the impact of antihistamines". It highlights that adverse CM-induced events seem to depend in the great majority upon (mainly non-IgE mediated) histamine release. These reactions promptly and completely respond to antihistaminics, while in some cases these drugs show little if any effect. In such circumstances other non-histamine mediators (e.g. leukotrienes) seem to play a pathophysiological role. The paper of Drs. Pascale Dewachter, Dominique Laroche, Claudie Mouton-Faivre, and Olivier Clément entitled "Immediate and late adverse reactions to iodinated contrast media: A pharmacological point of view" presents the current knowledge concerning the risk, pathophysiological mechanisms, clinical picture, diagnostic approaches and treatment modalities. The aim of this review is to report, from a pharmacological point of view, the most frequent types of immediate and delayed reactions following CM administrations, their incidence and their pathophysiological mechanisms. Dr. Sameh K. Morcos refers to "Life threatening and fatal contrast media reactions: pathomechanisms, diagnosis, prevention and drug management". He addresses that although very severe CM-induced reactions occur very rarely (ranging from 0.004% to 0.04%), they still pose a challenge. Patients with risk factors (e.g. history of a serious reaction to CM, bronchial asthma or multiple allergies) have an increased incidence of serious reactions, which however are unpredictable. The review presents the underlying patho-physiological mechanisms (such as direct activation of basophils and mast cells, IgE mediated reaction, activation of the kinin system, and the complement cascade) that may be involved, and the adequate therapy options. The ability to assess and treat serious CM reactions effectively is an essential skill that the radiologist should have and maintain. The paper "Vascular reactions of iodinated x-ray contrast media: mechanisms and possible therapeutic interventions" by Drs. Michael Uder and Marc Heinrich provides an interesting review of the CM-induced mechanisms of vasodilation and vasoconstriction. It explains that changes in vessel tone depend on the type of contrast medium, species, vascular territory and contractile state of the vessels. The authors describe the effects of high osmolar ionic, low osmolar non-ionic and isotonic contrast media on different vascular beds in humans and animals. Data from clinical and in vivo studies as well as from in vitro investigations on isolated organs and isolated vessel segments will be discussed. The review "Role of apoptosis in the pathogenesis of contrast media-induced nephropathy and hints for its possible prevention by drug treatment" by Drs. J.M. Idee, J. Boehm, P. Prigent, S. Ballet, and C. Corot refers to the pro-apoptotic effect of different iodinated and gadolinium-based contrast media. Proposed treatment modalities are highlighted. In addition, to the authors who have contributed to this issue, we would like to thank the members of the Editorial Advisory Board who reviewed the articles. We also would like to thank Bentham Science for their assistance, in particular Dr. Bahar Tunctan and Ms. Saima Rao.