Model dependence of gated blood pool SPECT ventricular function measurements

Area of Science:

• Nuclear Cardiology
• Cardiovascular Imaging
• Medical Physics

Background:

• Gated blood pool SPECT (GBPS) algorithms can yield varying results due to differing modeling assumptions.
• Limited data exists on discrepancies in right ventricular (RV) function calculations using GBPS.

Purpose of the Study:

• To compare the performance of two GBPS algorithms, QBS and BP-SPECT, in calculating ventricular function.
• To evaluate the accuracy of these algorithms against conventional methods and magnetic resonance imaging (MRI).

Main Methods:

• Evaluated QBS and BP-SPECT algorithms using patient data and dynamic phantom simulations.
• Correlated left ventricular (LV) and right ventricular (RV) ejection fraction (EF) with conventional planar-GBPS and MRI.
• Assessed gender differences and compared algorithm outputs to established MRI literature values.

Main Results:

• Both QBS and BP-SPECT showed strong correlations with conventional LVEF.
• BP-SPECT LVEF correlated more closely with MRI values than QBS.
• Both algorithms underestimated normal RVEF compared to MRI; BP-SPECT showed stronger correlation with MRI for RVEF than QBS.
• QBS consistently produced lower volume measurements than BP-SPECT across all data types.

Conclusions:

• While both algorithms accurately assess LV parameters, significant differences exist in their RV function calculations.
• BP-SPECT demonstrated superior agreement with MRI for both LVEF and RVEF compared to QBS.
• Discrepancies are attributed to the distinct ventricular modeling assumptions inherent in each algorithm.