Correlation between coronary artery calcium scoring (CACS) and abnormal myocardial perfusion imaging (MPI) in asymptomatic Pakistani population

Abstract

Background: Atherosclerotic plaques have strong correlation with the extent of coronary artery calcium scoring (CACS). Currently CACS screening is used as a reliable predictor of cardiovascular events in patients with atherosclerosis. Myocardial perfusion imaging (MPI) using single photon emission computerized tomography (SPECT), being the most used non-invasive modality for assessment of ischemia has been found to have good correlation with severity of CACS. Aim of this study was to find correlation between CACS and SPECT MPI in asymptomatic Pakistani population.

Methods and Materials: This was a retrospective study performed on 112 asymptomatic patients (Male: 95, Female: 17; mean age: 62.45 yr ±9) who underwent CACS screening and SPECT MPI between June 2025 till January 2026.  CACS measured by multidetector computerized tomography (MDCT) was categorized into 4 categories (CACS 0, CACS 1-100; CACS 201 -399; CACS ≥ 400). There was no significant difference between two genders for risk factors like hypertension (HTN), diabetes (DM), hypercholesterolemia (HC) and smoking but male has strong positive family history for coronary artery disease (CAD).

Results: Mean CACS in 112 patients was 699 (range: 0-3598; median: 428) and on subgroup analysis majority were found to have CACS ≥ 400 (CACS 0: 06/112 [5.4%]; CACS 1-100: 9/112 [08%]; CACS 101-399: 32/112 [29%]; CACS ≥400: 65/112 [58%]).  SPECT MPI was abnormal in 18/112 (16%) of total patients and on subgroup analysis all 6 patients in CACS=0, had a negative SPECT MPI. SPECT MPI was abnormal in 1/9 (11%) patients with CACS=1-100 while in group CACS=101-399, 4/32 (13%) had abnormal SPECT MPI. In group with CACS ≥400, 13/65 (20%) had abnormal SPECT MPI.  On risk factor analysis, in patients with CACS ≥ 400, an abnormal SPECT MPI was found to have significant correlation with risk factors like HTN, DM and HC (p<0.5)

Conclusion: We conclude that as per published international data, this study has also found a moderate agreement between CACS and abnormal SPECT MPI. The frequency of abnormal MPI with rising CACS is significantly lower in our population which could be due to selection of asymptomatic individuals. However, larger studies with inclusion of balanced gender, symptomatic and asymptomatic individuals are warranted.

Key words: coronary artery calcium score; CACS; SPECT; MPI; atherosclerosis; CAD