RSNA-Session: A computerized prediction model for individualized, patient-based contrast dosing at dual-source coronary CT angiography
Purpose
To achieve a desired level of enhancement with the least amount of contrast media (CM) at dual-source CT (DSCT) coronary angiography by using a computerized algorithm for patient-specific adaptation of CM volume and injection parameters.
Method and materials
In 32 patients undergoing CM (300 mgI/ml) enhanced coronary DSCT we used a computerized algorithm to individualize the volume and the parameters of the injection protocol. The algorithm is based on scan duration and patient specific variables such as weight, BMI, heart rate and circulatory state assessed by the peak attenuation and time-to-peak of a test bolus injection in the pulmonary artery and the aorta. 250 HU was selected as the target attenuation in the coronaries. The overall CM volume and injection rates were compared to our routine clinical protocol, which is based on scan duration only, at a fixed flow-rate of 6 cc/sec. Attenuation levels within the aorta and major coronaries were measured.
Results
The mean CM volume with use of the individualized injection protocol was 63.8±3.8 ml, with a mean injection rate of 4.1±0.2 ml/sec. The mean CM volume in the same patients, using the routine clinical protocol, would have been significantly (p<0.01) higher at 82.1±3.9 ml. Thus, a mean CM savings of 18.3±4.3ml was achieved. The mean attenuation in the ascending aorta and LM were 261.7±9 and 277.5±8.9 HU, respectively. Mean attenuation in the proximal, mid and distal segments of the LAD were 278±9.8, 254.7±11.2, and 259±11.5 HU; of the LCx 269.7±9.1, 245.5±10.4, and 233±8.2 HU; and of the RCA 273.6±8.9, 273.6±9.4, and 275±12 HU, respectively. The LM, proximal LAD and LCx, and the entire RCA had significantly higher attenuation than 250 HU (p<0.05). None of the remaining vessel segments were significantly different from our target attenuation of 250 HU (p=NS).
Conclusion
Patient-specific CM injection protocols based on the prediction model investigated here result in reliable coronary enhancement at a desired attenuation level while CM volumes are significantly reduced.
Clinical relevanc/application
Patient-based CM dosing at coronary DSCT may improve the consistency of vascular enhancement and aid appropriate CM use.
P Suranyi, MD, PhD, Charleston, SC; M J Kerl, BS; J F Kalafut, MS; H Lee, MD, PhD; P Costelo, MD; U Schoepf, MD; et al.
