A study on pre-injection test with mini-dose contrast medium in contrast-enhanced magnetic resonance angiography of vertebral artery

Objective: To evaluate mini-dose pre-injection test in the use of contrast-enhanced magnetic resonance angiography (CEMRA), and to inspect the possibility of contrast medium peak-time prediction by age, body weight and heart rate. Methods: The data from mini-dose pre-injection test of contrast medium before vertebral artery CEMRA were retrospectively reviewed in 55 patients. The linear correlation and regression of the data including age, body weight, heart rate, and the reaching-time, peak- value-time, duration and peak-value-signal of contrast medium was performed by using SPSS software. Results: The age (n=55, x-bar=62 years old, M=59 years old), body weight (n=55, x-bar 63 kg), heart rate (n=40, x-bar=73 beats per minute), peak-value-time (n=55, x-bar=17.5 seconds), peak signal intensity (n=55, x-bar=472), and duration of contrast (n=49, x-bar=10.35 seconds) were analyzed. No statistically significant correlation existed between peak-value-time of contrast medium and the age (r=0.231, t=1.728, P=0.090), body weight (r=0.118, t=0.865, P=0.392), and heart rate ( -0.046, t=-0.284, P=0.776). The peak-value-time correlated negatively with peak signal intensity (r=-0.322, t=-2.56, P=0.016) and positively with duration of contrast (r=0.658, t=5.99, P=0.000). The peak signal intensity was negatively correlated with body weight (r=-0.356, t=-2.77, P=0.008). The linear regression analysis show b=-0.284, t=-2.285, P=0.026 between peak-value-signal and peak-value-time, b=-0.322, t=2.590, P=0.012 between peak-value-signal and body weight. Conclusion: Mini-dose pre-injection test was more helpful to adjust the rate of contrast medium injection and determine the time delay during scanning. But the prediction of contrast peak-time based on age, body weight and heart rate was unreliable. (authors)