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Background Coronary artery calcium (CAC) detection is the established indication for a non-contrast enhanced cardiac computed tomography (NCE-CCT). Other information, beyond CAC, can be derived from the NCE-CCT. Amongst them, data regarding thoracic aorta and its abnormalities might be of interest. Aims We aimed at examination whether mutual proportion of ascending aorta and descending thoracic aorta diameters (AAD:DAD ratio) could be diagnostically relevant. Methods This retrospective study included 4372 patients out of 5905 subjects undergoing NC-CCT during the last decade, in whom the thoracic aorta and pulmonary artery trunk were within common limits (AAD≤40mm, DAD<30mm, PAD<30mm). 213 persons without CVD risk factors and CAC=0 were qualified into control group (1), and 4159 patients with CVD risk factor(s) ≥1 into examined group (2) of. The range of AAD/PAD ratio normality was referenced from the group 1. In addition body mass index and CAC score were accounted for. Results The AAD/PAD ratio in control group was 1.35±0.22 with the normal range between 1.12 and 1.57. The 90th percentile values for AAD have been established. In patients with CAC=0, amongst those with normal BMI the increased AAD:DAD ratio (>1.57), indicating high AAD, was found in 18 /43 cases with AAD>90 percentile (41.2%) and in 21/498 with normal AAD (4.2%). The respective proportions in overweight patients were 23/86 (26.7%) and 12/694 (1.7%), and in obese patients 13/67 (19.4%) and 5/397 (1.3%). In patients with CAC>0, and normal BMI the increased AAD:DAD ratio was found in 10/38 cases with AAD>90% (26.3%) and in 14/458 with normal ascending aorta size (3.1%). Proportions in overweight patients were 23/92 (25.0%) and 15/859 (1.75%), while in obese patients were 17/107 (15.9%) and 13/579 (2.2%), resp. Normal AAD:PAD ratio in patients with established AAD increase (>90 percentile), irrespective of BMI, might suggest accompanying increase in PAD. Lower AAD:PAD ratio indicated a relative increase of the DAD. Mean values of AAD and DAD in relation to BMI and CAC categories along with their ratio are presented in table 1. Conclusions Evaluation of thoracic aorta in NC-CCT enhanced diagnostic scope of NCE-CCT. The AAD/DAD ratio, being independent of age, gender and body constitution, does not require adjustment, should be considered as additional metric for early diagnoses of thoracic aorta abnormalities well before absolute values reach the arbitrary cut-off levels. Table 1 Funding Acknowledgement Type of funding source: None

Background Non-contrast-enhanced cardiac computed tomography (NCE-CCT) is currently used for coronary artery calcium (CAC) scoring. Meanwhile, other cardiac, vascular and extra-cardiac structures can be evaluated. Data about ascending aorta (AA) and left atrium (LA) has been quantified separately in a few studies. Their mutual proportion has not been examined, as yet. Aim. We hypothesize that mutual proportion between AA and LA size might help for diagnosing their enlargement before absolute cut-off values are reached. Method Among 7950 patients who had NCE-CCT with a 64 raw scanner (Aquillion, Toshiba) within the last decade in our center, in 797 persons the AA diameter (at the level of pulmonary artery bifurcation) and LA diameter and area (highest value) were measured. Raw AAD values were qualified as abnormal if exceeded upper normal limit UNL) for age and height. Weight, BMI and BSA has not been used in order to avoid falsified results in obese patients. The ratio AAD:LAD was quantified as low (<0.8), normal (0.8-1.2) and high (>1.2). Results There were 45 patients (5.6%) who had AAD higher than age-height predicted UNL, including 24 patients with a raw AAD >43mm (3.0%). The other 752 has their AAD within limits. The means of AAD were 42.9 ± 3.2mm and 33.6 ± 3.6mm (p < 0.001). LA size differed significantly, both in diameters 38.5 ± 7.4 vs 34.2 ± 5.6mm (p < 0.001) and areas 2138 ± 593 vs 1837 ± 481 mm2 (p < 0.001). Data regarding mutual relationship are shown in the fig.1. It is seen that normal mutual proportion (AOLARel =1) in patients with high AAD means that LAD was also increased (left graph, red open square). In 603 patients with normal AAD corresponded with normal LAD. The AAD:LAD >1.2 in 845 subjects might suggest increased AAD in spite to normal raw diameter. Similar rules were found in respect to the LA area. Conclusions Ascending aorta and left atrium enlargement are infrequently recognized in patients referred to CAC scoring. Mutual proportion between AA and LA size might complement diagnostic approach of their abnormalities.

Background Coronary artery calcium scoring is a main indication for a non-contrast-enhanced cardiac computed tomography (NCE-CCT). Great arterial vessels evaluation should be a part of CCT-based diagnosing. Purpose We aimed at analyzing data regarding great thoracic arterial sizes from a single-center cohort of 7950 patients who had NCE-CCT with a 64 raw scanner within the last decade. Methods In 5886 persons complete measurements of great arterial vessels' diameters at the level of the main pulmonary artery bifurcation were reported. The diameter of ascending aorta (AAD) was used to detect its enlargement on basis of absolute size, in relation to age and height (rAAD) and proportion to thoracic descending aorta (DAD) and main pulmonary artery (PAD). Respective criteria were: AAD≥43mm, rAAD>UNL for age/height (3.4+15.55*h+0.18*a), and AAD:DAD or AAD:PAD of 1.35 (range 1.1–1.6), both. Data were compared among patients with normal body mass index (BMI, kg/m2), overweight and obesity. Results Overall, increased absolute AAD was diagnosed in 149 persons (2.53%), rAAD>UNL in 358 (6.08%) and abnormal proportions AAD:DAD or AAD:PAD in 370 (13.0%) or 959 (16.3%), resp. Relative AAD was normal in 11 and 7 had normal proportions out of those with abnormal measured AAD. Among 138 patients with concordant absolute and relative increases, in 53 normal proportions were stated. In a cohort of 5737 patients with normal AAD (absolute), rAAD>UNL was found in 220 subjects (3.83%). Among remaining 5517 with normal both absolute and relative AAD, at least one abnormal proportion was found in 985 patients (17.9%). Taking into account BMI, the incidence of abnormal AAD was 0.3% in normal BMI patients (n=1409), 2,5% in overweight (n=2503) and 3.2% in obese (n=1974), while incidence of abnormal rAAD>UNL was 2.7%, 3.0% and 5.5%, resp. Abnormal proportions indicating abnormality within DAD or PAD were found in 1.1% and 3.8% normal BMI pts, in 2.4% and 4.7% overweight pts, and in 2.3% and 8.8% obese pts. Conclusions Absolute increase in ascending aorta size is relatively infrequent in patients referred to coronary artery calcium scoring. Use of age-height regression-based criteria increased diagnosis of abnormal ascending aorta size. Mutual proportions analysis among large arterial vessels showed further 5–6 fold increase in detection their abnormalities well before absolute or regression-based criteria are met. Great arterial vessels abnormalities are more frequent in overweight and obsese patients. Use of proportion analysis might be a step towards an individually-oriented medicine.

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