Being hydrophilic compounds, they can be classified 9 as ionic and non-ionic, with the latter having lower osmolarity for the same concentration (Table 1). The structure of gadolinium chelates may be linear or macrocyclic, with the latter being that which shows higher thermodynamic stability constants. This facilitates the recruitment of circulating fibrocytes, triggering the fibrosing reaction 7,8. In renal failure patients, it decreases the renal elimination of GBCM its half-life is extended, which increases the possibility of Gd3 dissociating from the chelate.
#Medios de contraste radiologia free#
Transmetalation is a chemical reaction whereby a secondary free metal with affinity for the chelate allows gadolinium release (Gd3). If this process continues, there is transmetalation and this causes NSF 6. There is a certain tendency for the ion to separate from the ligand in a process called chelation blocking 5. In its free form (Gd3) it is very toxic, and as such, it is necessary to chelate it with different organic ligands, creating gadolinium chelates 4.
Gadolinium (Gd) is a heavy metal with a high paramagnetic capacity and which is not soluble in water. Nine agents have currently been approved and are available in Europe their characteristics are summarised in Table 1.
However, if the GBCM concentration is high, T2 shortening is predominant, which causes a decrease in the signal. These contrast media act by shorting the T1 and T2 relaxation time of the tissues to which they are distributed, which fundamentally leads to an increased signal in T1-weighted sequences. Gadolinium-based contrast media (GBCM) are used in magnetic resonance imaging (MRI) studies due to their magnetic ability to change the position of the protons of water molecules in tissues, which is a change that improves the study’s diagnostic capacity. In this document, we aim to summarise the clinical expression of NSF, the data known about different gadolinium-based contrasts, the possibilities of identifying patients at risk in order to prevent its onset and the types of treatment for this disease. It has been defined as a fibrosing disease that predominantly affects patients who have received gadolinium-based contrasts, with an estimated glomerular filtration rate (GFR) of less than 30ml/min/1.73m 2 or those on haemodialysis 2,3. Since 1997, when it was reported by Cowper for the first time 1, a condition called nephrogenic systemic fibrosis (NSF) has drawn the attention of nephrologists and radiologists from all over the world. En un encuentro entre radiólogos y nefrólogos revisamos los aspectos más relevantes en la actualidad y las recomendaciones para su prevención. La estrecha farmacovigilancia y el rigor en la observación de las normativas actuales, con especial atención al valor del filtrado glomerular, han reducido los casos publicados relacionados con el uso de medios de contraste basados en el gadolinio. Se han intentado establecer parámetros de seguridad a fin de identificar a los pacientes con factores de riesgo por presentar insuficiencia renal. A pesar de tratarse de un grupo de fármacos que se consideraban seguros, la notificación de esta reacción adversa, potencialmente grave, supuso un punto de inflexión en las pautas de administración de estos medios de contraste. La fibrosis sistémica nefrogénica es un trastorno fibrosante que afecta a pacientes con deterioro de la función renal y se asocia a la administración de medios de contraste basados en el gadolinio, empleados en la resonancia magnética.
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