Final answer:
Increasing the number of frames from 8 to 16 in an imaging study does not affect the calculated ejection fraction (EF), as EF is defined by absolute volumes of blood in the heart, which are not dependent on the number of frames in an imaging sequence.
Step-by-step explanation:
When discussing ejection fraction (EF), increasing the number of frames from 8 to 16 in an imaging study for measuring EF does not change the calculated EF value. EF is a measurement used to assess how well the heart is pumping blood with each beat. It is calculated by dividing the stroke volume (SV), which is the volume of blood pumped from the heart's left ventricle with each heartbeat, by the end-diastolic volume (EDV), which is the total volume of blood in the ventricle before it contracts. Since both the SV and EDV are absolute volumes and are not influenced by the number of frames in an imaging sequence, the calculation of EF remains constant regardless of the number of frames used during the imaging process. What is key is that the actual volumes are accurately measured; the frames only determine the temporal resolution of the imaging.