An Investigation of Transient Severe Motion Related to Gadoxetic Acid-enhanced MR Imaging

Abstract

Purpose: To investigate the cause of imaging artifacts observed during gadoxetic acid-enhanced arterial phase imaging of the liver.

Materials and methods: This HIPAA-compliant study was approved by the institutional review board. Data were collected prospectively at two sites (site A, United States; site B, Japan) from patients undergoing contrast material-enhanced MR imaging with gadoxetic acid (site A, n = 154, dose = 0.05 mmol/kg; site B, n = 130, 0.025 mmol/kg) or gadobenate dimeglumine (only site A, n = 1666) from January 2014 to September 2014 at site A and from November 2014 to January 2015 at site B. Detailed comparisons between the two agents were made in the patients with dynamic liver acquisitions (n = 372) and age-, sex-, and baseline oxygen saturation (Spo2)-matched pairs (n = 130) at site A. Acquired data included self-reported dyspnea after contrast agent injection, Spo2, and breath-hold fidelity monitored with respiratory bellows.

Results: Self-reported dyspnea was more frequent with gadoxetic acid than with gadobenate dimeglumine (site A, 6.5% [10 of 154] vs 0.1% [two of 1666], P < .001; site B, 1.5% [two of 130]). In the matched-pair comparison, gadoxetic acid, as compared with gadobenate dimeglumine, had higher breath-hold failure rates (site A, 34.6% [45 of 130] vs 11.7% [15 of 130], P < .0001; site B, 16.2% [21 of 130]) and more severe artifacts during arterial phase imaging (site A, 7.7% [10 of 130] vs 0% [none of 130], P < .001; site B, 2.3% [three of 130]). Severe imaging artifacts in patients who received gadoxetic acid were significantly associated with male sex (P = .023), body mass index (P = .021), and breath-hold failure (P < .001) but not with dyspnea or Spo2 decrease.

Conclusion: Severe motion-related artifacts in the arterial phase of gadoxetic acid-enhanced liver MR imaging are associated with breath-hold failure but not with subjective feelings of dyspnea or a substantial decrease in blood Spo2. Subjective feelings of dyspnea are not necessarily associated with imaging artifacts. The phenomenon, albeit at a lower rate, was confirmed at a second site in Japan.

Figure 1

Study flowchart shows inclusion and exclusion of patients.

Figure 2

Respiratory bellows were used to monitor the success of breath holding. Breath-hold success was defined as a straight or slowly varying trace during image acquisition. Breath-holding failure was recognized as the occurrence of sudden oscillations in bellows tracing in this figure. The example images were obtained in a 50-year-old man (success) and a 67-year-old man (failure).

Figure 3

Examples of image quality grading. The grade of artifacts was assessed by using a four-point scale. Moderate or severe artifacts were combined and classified as “substantial” artifacts. The example images were obtained in a 67-year-old woman (no artifact), a 63-year-old man (mild artifact), a 50-year-old woman (moderate artifact), and a 33-year-old man (severe artifact).

Figure 4

Diagram shows overlap of recorded breath-holding failures, image artifacts, and self-reported dyspnea for both sites. Substantial artifacts were frequently associated with breath-holding failure (determined by using a respiratory bellows) at both site A (24 of 29) and site B (14 of 20). Severe artifacts were always observed in patients with failed breath holding during the examination. Self-report of dyspnea was associated with breath-hold failure (six of eight at site A and two of two at site B). Interestingly, self-report of dyspnea was not necessarily associated with imaging artifacts.