Fig. 2

Technical background for generating temporal reconstruction windows of MSR and HSR (a) and their dependency on patient’s heart rate (b). a The minimum partial scan raw data needed to reconstruct a volume require half a gantry rotation (+ fan angle). HSR uses partial scan raw data acquired within one heart beat (illustrated on the left in light grey) and consequently generates a per-segment temporal reconstruction window of half a gantry rotation. MSR uses partial scan raw data of approximately half a gantry rotation acquired in at least two successive heart beats, illustrated on the right for two segments in dark grey (segment one) and black (successive segment two). The resulting minimum per-segment temporal reconstruction window of MSR can be calculated as follows: Temporal reconstruction window = gantry rotation time / (2 × number of acquired segments). Thereby, acquiring more segments improves the per (heart)-segment temporal reconstruction window of MSR compared with HSR by up to the same factor as the number of segments acquired [see references [7,8,9,10,11]] at the cost of a higher radiation dose [see references [8, 12]]. b Line graphs showing the per-segment temporal reconstruction window of MSR and HSR depending on individual patient’s heart rate for a 350-ms gantry rotation time and acquisition of up to four segments. The temporal reconstruction window of HSR is always 175 ms, whereas the temporal reconstruction window of MSR ranges from 44 to 175 ms depending on heart rate. Data by courtesy of the equipment vendor. HSR Halfscan reconstruction, MSR Multisegment reconstruction