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 (t1, t2, . . . ,tn) of a common, reoccurring reference point (R1, 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 (R1, 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).