Rapid dual-injection single-scan 13N-ammonia PET for quantification of rest and stress myocardial blood flows

摘要

Quantification of myocardial blood flows at rest and stress using ¹³N-ammonia PET is an established method; however, current techniques require a waiting period of about one hour between scans. The objective of this study was to test a rapid dual-injection single-scan approach, where ¹³N-ammonia injections are administered 10 minutes apart during rest and adenosine stress. Dynamic PET data were acquired in six human subjects using imaging protocols that provided separate single-injection scans as gold standards. Rest and stress data were combined to emulate rapid dual-injection data so that the underlying activity from each injection was known exactly. Regional blood flow estimates were computed from the dual-injection data using two methods: background subtraction and combined modeling. The rapid dual-injection approach provided blood flow estimates very similar to the conventional single-injection standards. Rest blood flow estimates were affected very little by the dual-injection approach, and stress estimates correlated strongly with separate single-injection values (r = 0.998; mean absolute difference = 0.06 ml/min/g). An actual rapid dual-injection scan was successfully acquired in one subject and further demonstrates feasibility of the method. This study with a limited dataset demonstrates that blood flow quantification can be obtained in only 20 minutes by the rapid dual-injection approach with accuracy similar to that of conventional separate rest and stress scans. The rapid dual-injection approach merits further development and additional evaluation for potential clinical use.