In the detection of coronary heart diseases amongst the non-invasive techniques the role of myocardial perfusion imaging is indexed. The rationale of this study was to compare the different parameters and the association between the exercise MPI and vasodilator MPI in the detection of coronary artery disease (that is prolonged Qt interval with the size of perfusion defects). It was a cross-sectional prospective study with purposive non-probability sampling technique which was conducted in a tertiary care hospital from January 2020 to June 2020 for a period of 6 months. All patients regardless of gender were included in this study and age ranging from 30 to 80 years with comorbidities ranging from diabetes, hypertension and smokers were also included. A total of 100 patients were included in this study out of which 81% were male, 50% were diabetics, 69% were hypertensive, 39% had a history of coronary artery disease, 25% were smokers and 63% had hyperlipidemia. For statistical analysis SPSS 21 was applied and significant association was observed between DTS treadmill score and the perfusion defect in vasodilator MPI, corrected Qt interval and DTS tread mill score and between corrected Qt and size of the perfusion defect (P value < 0.001). It was thus seen that the different components of the noninvasive nuclear stress test tend to co-relate and thus aid in the detection of coronary artery disease increasing the accuracy of results.