Signal quality of single dose gadobenate dimeglumine pulmonary MRA examinations exceeds quality of MRA performed with double dose gadopentetate dimeglumine

Abstract

During a recent multi-center trial assessing gadolinium (Gd)-enhanced magnetic resonance angiography (MRA) for diagnosis of acute pulmonary embolism (PE), the Food and Drug Administration announced a risk of nephrogenic sclerosing fibrosis in patients with renal insufficiency who had received intravenous Gd-based MR contrast agents. Although no patients in this trial had renal insufficiency, in cautious response to this announcement, the trial protocol was changed from an intravenous administration of 0.2 mmol/Kg of a conventional Gd-based MR contrast agent to 0.1 mmol/Kg of gadobenate dimeglumine. The study described herein compares the signal quality of pulmonary MRA performed with double dose conventional agent to single dose gadobenate dimeglumine. This study is a retrospective analysis of data from a prospective, multicenter study in men and women ≥18 years with documented presence or absence of PE. The study was approved by the Institutional Review Board at all participating centers, and all patients provided written indication of informed consent. We performed both objective and subjective analysis of pulmonary artery image quality. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the main pulmonary artery were assessed in single and double dose protocols and compared. SNR and CNR of the main PA were correlated with subjective quality assessment of main/lobar, segmental and subsegmental pulmonary arteries. Although there were individual outliers, both SNR (P = 0.01) and CNR (P = 0.008) were higher in all quartiles for examinations using gadobenate dimeglumine than with gadopentetate dimeglumine. Subjective quality of vascular signal intensity at each vessel order was significantly better for gadobenate dimeglumine (P < 0.0001), and correlated well with SNR and CNR at each order (<0.001). Because of agent high relaxivity, a single dose of gadobenate dimeglumine provides better pulmonary MRA signal quality than double dose of a conventional Gd-based MR contrast agent.

Fig. 1

Box-and-whisker plots show the distribution of signal-to-noise (SNR) and contrast-to-noise (CNR) in pulmonary MR angiograms performed in PIOPED III. The box shows the 25th to the 75th percentile. The top of the line is the maximum and the bottom line is the minimum in the distribution. SNR and CNR values are unitless. The P values are from the non-parametric Wilcoxon two-sample test using the normal approximation

Fig. 2

Box-and-whisker plots show SNR by subjective quality assessment of arterial phase opacification and vessel. The box shows the 25th to the 75th percentile. The top of the line is the maximum and the bottom line is the minimum in the distribution. SNR and CNR values are unitless. P < 0.001

Fig. 3

Box-and-whisker plots show CNR by subjective quality assessment of arterial phase opacification and vessel. The box shows the 25th to the 75th percentile. The top of the line is the maximum and the bottom line is the minimum in the distribution. SNR and CNR values are unitless. P < 0.001