To investigate the clinical usefulness of coronary arteriography using a gadolinium contrast medium (hereinafter referred to as Gd contrast medium) in patients with iodine allergy, images obtained using an iodinated contrast medium and a Gd contrast medium were compared using respective phantoms. Within the range of the effective energy (34.8 to 41.0 keV) in clinical use, the tube-voltage dependency of the Gd contrast medium was lower than that of the iodinated contrast medium. The contrast ratios were found to be comparable for the images obtained by a 4-fold-diluted iodinated contrast medium and the undiluted Gd contrast medium. Although the assessment of stenotic ratio was difficult to obtain by visual evaluation of the clinical images, due to unclear borders of the blood vessels, the presence or absence of significant stenosis was discriminative by arteriography using the Gd contrast medium. Based on these findings, it was considered necessary to make a confirmed diagnosis using a Gd contrast medium with concurrent diagnosis by intravascular echography. In conclusion, coronary arteriography and PCI using a Gd contrast medium are considered to offer benefit to the diagnosis and treatment of patients with iodine allergy.
