Abstract
775
Objectives: In SPECT semiquantitative analysis of myocardial perfusion [SSS/SRS scores] proved to be important for diagnosis of coronary artery disease[CAD]. Most laboratories use pre_installed database provided with quantitative software package. However characteristics of Manufacturer’s normal database [M-NDBs], created from patients with a low likelihood of cardiac disease [<5%], often don’t fit Institutional local population: use of an inappropriate database could influence performance of any quantitative software. Indeed studying normal population in different geographic areas significant physical differences may be found. Hence the need to create an Institutional local database [I_NDB] for each/many laboratories. Aim: We evaluated the effect of body mass index [BMI] as a significant variable in diagnostic performance on quantitative myocardial perfusion SPECT results using QPS M_NDB versus I_NDB.
Methods: Methods: Forty male_patients [45+10yrs] and forty female_patients [40+12yrs] scheduled for Tc99m-Sestamibi SPECT during 2013-2016 period were selected to generate a gender specific I_NDB using Cedars Sinai Suite AutoQuant[PFQ]. All patients referred in suspicion of CAD with a pretest low likelihood of cardiac disease [at least 1 risk factor] had BMI >30; underwent stress exercise on a bicycle ergometer; Gated_SPECT was performed using double-head Siemens Symbia-S equipped with LEHR collimators. Myocardial Perfusion scores [SSS,SRS,SDS] and coronary territory extent[LAD,LCx,RCA] were calculated both at stress and rest using QPS. Exclusion criteria were diabetes, ECG abnormalities[LBBB, PM] and history of CAD [revascularization, infarction].
Results: Results: In males only SDS differed significantly [p<0.03] between M_NDB and I_NDB [2.4 vs 3.5 mean values respectively]; perfusion defect extent PDEx was larger as Total Value both at stress and rest [0.017, 0.002]; specifically in RCA territory [p<0.011] at stress and LCx [p<0.002]at rest. In females SRS [p<0.043] and SDS [p<0.043] were significantly different between M_NDB and I_NDB. As regards coronary territories PDEx was larger in LAD both at stress [p<0.027]and rest [p<0.02]; and LCx at rest [p<0.047].
Conclusion: In our experience I_NBD, as compared to M_NDB, seem to better identify extent and severity of perfusion defects in a specific subgroup of patients with BMI >30. In particular significant differences were observed in myocardial segments / coronary territories in which soft tissue attenuation is relevant: inferior/inferolateral in males and anteroseptal wall in females.