Additive Value of Evaluating Diastolic Function by CT Compared to Echo-Doppler

Background:

We have recently shown that evaluation of cardiac chamber volume curves can identify diastolic dysfunction compared to echocardiography. We now wished to analyse the additive value of cardiac CT by evaluating the regions of disagreement between the two modalities.

Methods:

103 consecutive patients with both multiphase cardiac CT and echo-Doppler within 1 month were identified. Based on ASE guidelines, diastolic function was graded as normal (n=33), mild (n=13), moderate (n=34), severe (n=6) or indeterminate (n=17). Automatically determined left atrial (LA) volume curves were extracted from the CT datasets, and various parameters of LA filling and emptying calculated. Based on previous studies a value of LA total emptying fraction (LATEF) <32% was used to determine diastolic dysfunction (DD) manifesting increased LV filling pressures.

Results:

Based on echo-Doppler classification, abnormal LATEF was found in one of 33 normal cases, in 3 of 13 mild, 22 of 34 moderate, 6 of 6 severe and 4 of 17 indeterminate cases. Mean LATEF was 46±9% for normal, 41±9% for mild, 29±11% for moderate, 17±9% for severe and 40±10% for indeterminate cases. For the moderate DD group, 12 CT normal (LATEF 42±7%) were compared with 22 CT abnormal cases (LATEF 22±6%). The 12 CT normal cases had significantly smaller LA volumes, and higher left ventricular ejection fractions; systolic LA filling was significantly better as was active LA emptying but early LA emptying volumes and conduit volumes were similar.

Conclusions:

In general assessment of diastolic function has a good agreement with echo-Doppler based results, however a significant near-normal subset of "pseudonormal" cases, was identified, characterized by normal LV and LA contractile function with smaller LA volumes. Direct comparison with invasively measured pressures is required to better understand the significance of these findings.