Iterative reconstruction does not substantially delay CT imaging in an emergency setting

OBJECTIVES: To evaluate the effects of iterative reconstruction (IR) on reconstruction time and speed in two commonly encountered acquisition protocols in an emergency setting: pulmonary CT angiography (CTA) and total body trauma CT. METHODS: Twenty-five patients underwent a pulmonary CTA for evaluation of pulmonary embolisms and 15 patients underwent a total body CT after a traumatic event on a 256-slice CT. Images were reconstructed with filtered back-projection (FBP) and two IR levels. Reconstruction time and speed were quantified using custom written software. RESULTS: Mean reconstruction time delays for pulmonary CTAs were 10 ± 10 s and 12 ± 12 s for IR levels 2 and 4, respectively, and 44 ± 8 s and 45 ± 7 s for total body trauma CTs for IR levels 1 and 6, respectively. Mean reconstruction times and speeds for pulmonary CTAs were 26 ± 7 s, 36 ± 9 s and 38 ± 12 s, and 26.7 ± 5.6 slices/s, 18.7 ± 2.3 slices/s and 18.0 ± 2.8 slices/s for FBP, IR levels 2 and 4, respectively. For total body trauma CTs these values were 87 ± 15 s, 132 ± 17 s and 132 ± 18 s, and 20.1 ± 1.6 slices/s, 13.2 ± 0.8 slices/s and 13.2 ± 0.6 slices/s for FBP, IR levels 1 and 6, respectively. CONCLUSIONS: IR does not result in clinically important CT image reconstruction delays in an emergency setting. No substantial differences in reconstruction time and speed were found between different IR levels. MAIN MESSAGES: IR delayed total pulmonary CTA reconstruction with 10–12 s and total-body trauma CT with 44–45 s. IR is not substantially delaying reconstruction in emergency CT imaging. Reconstruction time and speed are similar for different levels of IR.