PURPOSE To achieve a consistent enhancement in coronary CT angiography (CCTA) by implementing a contrast injection protocol with adjusted iodine concentration based on patient habitus and kVp. METHOD AND MATERIALS Retrospective data from 80 consecutive patients (group 1) scanned on a Revolution CT (GE Healthcare) with one-heartbeat automated triggering, 100 kVp (N=74) or 120 kVp (N = 6), noise index = 25 and standard iodine dose (70 ml of 370 mg I / ml, 350 mg I / ml or 320 mg I / ml) was collected, using DoseWatch (GE Healthcare). The optimal correlation between arterial enhancement (HU) and body habitus normalized to total iodine dose (TID) was determined by considering following parameters: weight, Body Mass Index (BMI), Body Surface Area (BSA), Lean Body Mass (LBM) and Fat Free Mass (FFM). From the parameter giving the best correlation, a model for optimal contrast concentration to achieve a target enhancement value of 550 HUtarget was determined and prospectively applied to 62 patients (N=1 at 80 kVp, N=55 at 100 kVp and N=6 at 120 kVp) undergoing a CCTA exam (group 2). Personalized iodine concentration was administered by parallel mixing of iodine with saline on a dual-head power injector (Nemoto-Kyorindo, Japan). Enhancement was compared between group 1 and 2 (Mann-Whitney U- test) and homogeneity of variances was tested (Levene’s test). RESULTS Compared to other body habitus parameters (R² range 0.1 – 0.5), Free Mass (FFM) showed the strongest correlation (R² = 0.5) with enhancement. Following contrast injection model was established for 100 kVp: TID = (HUtarget - 237)*FFM/946; for 120 and 80 kVp TID should be scaled by 1.22 and 0.77 respectively. With the modified protocol, variance (standard deviation) reduced from 102 HU to 67 HU (p < 0.01). The mean enhancement 506 HU was lower than the target 550 HU (p <0.01). CONCLUSION An injection protocol with contrast concentration adapted to body habitus, iodine concentration and kVp improves patient-to-patient CT value uniformity. CLINICAL RELEVANCE/APPLICATION Personalizing the iodine injection protocol for CCTA homogenizes image quality in terms of contrast enhancement for an easier interpretation and correlation of images.
Original languageEnglish
Title of host publicationRSNA 2016 Scientific program
Publication statusPublished - 2016
EventRadiological Society of North America 2016 Scientific Assembly and Annual Meeting - Chicago, United States
Duration: 27 Nov 20162 Dec 2016
http://archive.rsna.org/2016/16009761.html

Conference

ConferenceRadiological Society of North America 2016 Scientific Assembly and Annual Meeting
CountryUnited States
CityChicago
Period27/11/162/12/16
Internet address

ID: 29010669