Technical considerations for MIBG cardiac scintigraphy

The most commonly used means of imaging to assess cardiac sympathetic denervation is cardiac ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) scintigraphy. The heart-to-mediastinum (H/M) ratio generated by planar imaging is used widely to assess sympathetic nerve involvement. The H/M ratio is a simple and reliable index, but its values can be influenced profoundly by differences in collimators. Region of interest (ROI) setting methods are also an important problem to generate reliable data. More recently, multicenter cross-calibration of ¹²³I-MIBG H/M ratios to overcome camera-collimator variations, with the use of reference H/M ratios assessed by the phantom method and of a conversion coefficient for each camera-collimator system, demonstrated that H/M ratios under various conditions can be converted to standard H/M ratios for a range of ratios from normal to low. In addition, a standardized method for semiautomatic ROI setting in MIBG was developed. These technical advancements enable us to promote multicenter studies. We also discuss the imaging technique, analysis, and interpretation in this section.