Left-sided cardiac chamber evaluation using single-phase mid-diastolic coronary computed tomography angiography: derivation of normal values and comparison with conventional end-diastolic and end-systolic phases.

Objectives: With increasing use of prospective scanning techniques for cardiac computed tomography (CT), meaningful evaluation of chamber volumes is no longer possible due to lack of normal values. We aimed to define normal values for mid-diastolic (MD) chamber volumes and to determine their significance in comparison to maximum volumes.

Methods: Normal ranges at MD for left ventricular (LV) volume and mass and left atrial (LA) volume were determined from 101 normal controls. Thereafter, 109 consecutive CT scans, as well as 21 post-myocardial infarction patients, were analysed to determine the relationship between MD and maximum volumes.

Results: MD volumes correlated closely with maximal volumes (r = 0.99) for both LV and LA, and could estimate maximum volumes accurately. LV mass, measured at ED or MD, were very similar (r = 0.99). Abnormal MD volumes had excellent sensitivity and specificity to detect chamber enlargement based on maximal volumes (LV 86 %, 100 %, respectively; LA 100 %, 92 %, respectively).

Conclusion: A single MD phase can identify patients with cardiomegaly or LV hypertrophy with a high degree of accuracy and MD volumes can give an accurate estimate of maximum LV and LA volumes.

Key Points: • Traditionally, helical cardiac CT provided clinically important information from chamber volume analysis. • Mid-diastolic left atrial and ventricular volumes correlate closely with maximal volumes. • We derive normal values for mid-diastolic left atrial and ventricular volumes and mass. • A single mid-diastolic phase can be used to identify chamber enlargement and hypertrophy.