Hybrid cardiac imaging: insights in the dilemma of the appropriate clinical management of patients with suspected coronary artery disease.

Aim: To evaluate the potential of SPECT myocardial perfusion imaging (MPI)-computed tomography coronary angiography (CTCA) hybrid fusion imaging to improve the diagnostic performance of cardiac SPECT/MPI and CTCA alone in order to act as more accurate gate keeper to further investigation invasive or not.

Methods And Results: Twenty-five patients were subjected to SPECT/MPI and CTCA within a period of 1 month without any medical treatment modification. A fusion software package was used for cardiac SPECT-CTCA image fusion. Semiquantitative analysis was performed for cardiac SPECT, CTCA and SPECT/MPI-CTCA fusion images. Patients were classified in 2 groups according to the clinical decision for further investigation (group A), or not (group B). Statistically significant differences were observed when SPECT/MPI-CTCA fusion images were used instead of cardiac SPECT alone (p<0.05). No statistically significant differences were observed comparing CTCA alone to SPECT/MPI-CTCA fusion images (p=0.25). A mid-term follow-up (mean 3.58 ± 0.24 years) showed that all patients classified in group A based on the interpretation of SPECT MPI-CTCA fused images underwent conventional coronary angiography with further necessity for PTCA or CABG whereas absence of major or minor cardiac events was revealed for all patients of group B.

Conclusion: In patients suspected for coronary artery disease, cardiac SPECT/MPI-CTCA fusion imaging was found to considerably alter the clinical decision for referral to further investigation derived from SPECT/MPI.