Variations in 123I-metaiodobenzylguanidine (MIBG) late heart mediastinal ratios in chronic heart failure: a need for standardisation and validation

Abstract

There is lack of validation and standardisation of acquisition parameters for myocardial ¹²³I-metaiodobenzylguanidine (MIBG). This lack of standardisation hampers large scale implementation of ¹²³I-MIBG parameters in the evaluation of patients with chronic heart failure (CHF). In a retrospective multi-centre study ¹²³I-MIBG planar scintigrams obtained on 290 CHF patients (82% male; 58% dilated cardiomyopathy; New York Heart Association [NYHA classification] > I) were reanalysed to determine the late heart-to-mediastinum ratio (H/M). There was a large variation in acquisition parameters. Multivariate forward stepwise regression showed that a significant proportion (31%, p < 0.001) of the variation in late H/M could be explained by a model containing patient-related variables and acquisition parameters. Left ventricular ejection fraction (p < 0.001), type of collimation (p < 0.001), acquisition duration (p = 0.001), NYHA class (p = 0.028) and age (p = 0.034) were independent predictors of late H/M. Acquisitions parameters are independent contributors to the variation of semi-quantitative measurements of cardiac ¹²³I-MIBG uptake. Improved standardisation of cardiac ¹²³I-MIBG imaging parameters would contribute to increased clinical applicability for this procedure.