Validity of automatic function imaging to measure peak systolic strain for detection of myocardial viability as compared with Thalium MPI

Abstract

Thallium201 myocardial perfusion scintigraphy (MPI) is the most common modality used myocardial viability (MV), automatic function imaging (AFI) to measure peak systolic strain is relatively recent Echocardiographic modality with questionable validity for detection of viability. To evaluated the validity of peak systolic strain for detection of MV as compared with Thallium MPI. Methods: 50 patients with myocardial infarction will be included in our prospective study. Thallium MPI to be used as reference for MV (Rest-4 h and if necessary 24 h protocol). The automatically generated Bulls eye image will be used for quantitative segmental analysis and to be compared with Echocardiographic AFI for peak systolic strain with the 17 segments model of analysis (GE system). The results will be compared as segment by segment as well as regional (as per coronary territory). We present the result of first 10 case series (including analysis of 170 segments). There is over all concordance between the automated count at image of peak systolic strain and the percent of radiotracer uptake at Thallium 201 bulls eye images in both infracted and non infracted segments. The cut value of AFI for viability requires larger sample analysis. There is observed false negative results at segments with very low peak systolic strain as low as-2 that showed mild perfusion defect at rest and complete reuptake at redistribution image. Peak systolic strain is useful modality for assessment of viability, its sensitivity might be limited with false negative results compared with Thallium 201 scintigraphy.