In a diagnostic imaging system (10), a monitor (50) monitors periodic biological cycles of the subject (14). A trigger point detector (60) detects a time (tl, t2, ..., tn) of a common, reoccurring reference point (Rl, R2, ..., Rn) in each periodic cycle of the subject (14). A sequence selector (62) selects a sequence (64) of nominal sampling segments (Si, S2, ..., Sn). An adjustor (70) adjusts duration of each nominal sampling segment (Si, S2, ..., Sn) to coincide with the times of detected reference points (Rl, R2, ..., Rn). A scaling processor (72) scales each adjusted segment based on a difference in duration between the corresponding nominal (Si, S2, ..., Sn) and adjusted sampling segments (S'i, S'2, ..., S'n).