We used the EKG modulation of the anodic electricity (maximal current between 40% and 80% of the R-R interval of the cardiac cycle; outside of this interval,
30% of maximum electricity value was used).
The highest mA value to be employed in the percentage of the evaluated R-R interval was chosen based on the patients' BMI index,
so as to obtain values between 116,7 ± 10 mA and 388,9 ± 33,3 mA.
Between June 2017 and September 2017,
9 patients (post- optimised protocol) were studied by coronary CTA.
Acquisition parameters were the following: 64 x 0.625 collimation,
slice thickness 0,625 mm,
0.35-s rotation time with 100-kV tube voltage.
In another group of 9 patients (pre-optimised protocol) acquisition parameters of cCTA were the following: 120-kV tube voltage and current from 600 mA to 250 mA at 40-80% of R-R interval of cardiac cycle.
The scan for the evaluation of the coronary circulation spanned from the main pulmonary artery to a few inches below the cardiac apex.
All patients were administered a bolus of 60 ml of Iomeron 400,
and the scan was synchronized using Smart Prep bolus tracking.
In the same period,
11 TAVI candidates patients (post- optimised protocol),
were studied by CTA.
Acquisition parameters were the following: 64 x 0,625 collimation,
slice thickness 1,25 mm,
0.35-s rotation time with 100-kV tube voltage.
In another group of 11 TAVI candidates patients (pre-optimised protocol) acquisition parameters were the following: 120-kV tube voltage and current from 600 mA to 250 mA at 40-80% of R-R interval of cardiac cycle.
The aortic evaluation scan encompasses the thorax and abdomen from the supra-aortic trunks to the femoro-iliac axis.
After the injection of 120 ml of Iomeron 400,
Smart Prep bolus tracking system was used to synchronize the scan.
The images of each group of patients were sent to a dedicated workstation,
where a skilled radiologist evaluated them and filled in the diagnostic report.
To be able to compare the images,
and to assess the eligibility of each image in order to work out a diagnosis,
we developed a grading system consisting of a score fom 1 to 4,
where 1 corresponds to “poor image quality,
insufficient for a diagnostic report”,
2 is “image quality sufficient for a diagnostic report”,
3 is “good image quality” and 4 corresponds to “optimal image quality”.
Data was expressed as mean ± standard deviation.
The dosimetric indexes DLP (dose lenght product) and E (effective dose) were employed to compare the dosimetric parameters.
Mean,
maximum and minimum levels for each parameter were compared by means of two-tail Student t-test.
A p value <0.05 was considered statistically significant,
while p<0.01 was considered highly significant.