Evaluation of a tailored injection profile (TIP) algorithm for uniform contrast-enhanced signal intensity profiles in MR angiography.

PURPOSE: To evaluate a contrast agent injection method that provides constant magnetic resonance imaging (MRI) signal intensity throughout a contrast-enhanced MR angiography acquisition.

MATERIALS AND METHODS: A tailored injection profile (TIP) algorithm was developed that used the signal intensity profile from a test bolus as an impulse response function, and predicted the response to various multiphasic injection profiles. Antecubital vein injections were administered via a commercially available multiphasic power injector. The TIP algorithm evaluated the predicted responses and selected the injection that best matched the desired (20-sec plateau) profile. Resulting signal intensity profiles from tailored and standard injection profiles were compared in 20 subjects (10 each). All subjects received a weight-based single-dose (0.1 mmol/kg) of gadoteridol, and abdominal aorta signal intensities were measured at 3T with a time-resolved, thick-slice, 3D spoiled-gradient-echo MR sequence with parameters approximating contrast-enhanced MR angiography. The single-phase, standard injection was injected at 1.6 mL/sec.

RESULTS: Full-width at 80% maximum (FW80M) signal intensity was significantly longer for the tailored injection profiles (23.0 ± 2.2 vs. 9.0 ± 4.2 sec; P < 0.01). Concurrently, the profile peak signal intensity was reduced by 19% for the tailored profiles (12.0 ± 3.1 vs. 14.8 ± 2.8 times baseline; P = 0.058), nearly reaching significance.

CONCLUSION: Multiphasic tailored injections from a power injector produced longer signal intensity profiles (156% increase in FW80M) with an accompanying decrease (19%) in peak signal intensity compared to a standard, single-phase injection. J. Magn. Reson. Imaging 2016. J. Magn. Reson. Imaging 2016;44:1664-1672.