Can gadolinium contrast agents be replaced with saline for direct MR arthrography of the hip? A pilot study with arthroscopic comparison

Abstract

Objective: To compare image quality and diagnostic performance of preoperative direct hip magnetic resonance arthrography (MRA) performed with gadolinium contrast agent and saline solution.

Methods: IRB-approved retrospective study of 140 age and sex-matched symptomatic patients with femoroacetabular impingement, who either underwent intra-articular injection of 15-20 mL gadopentetate dimeglumine (GBCA), 2.0 mmol/L ("GBCA-MRA" group, n = 70), or 0.9% saline solution ("Saline-MRA" group, n = 70) for preoperative hip MRA and subsequent hip arthroscopy. 1.5 T hip MRA was performed including leg traction. Two readers assessed image quality using a 5-point Likert scale (1-5, excellent-poor), labrum and femoroacetabular cartilage lesions. Arthroscopic diagnosis was used to calculate diagnostic accuracy which was compared between groups with Fisher's exact tests. Image quality was compared with the Mann-Whitney U tests.

Results: Mean age was 33 years ± 9, 21% female patients. Image quality was excellent (GBCA-MRA mean range, 1.1-1.3 vs 1.1-1.2 points for Saline-MRA) and not different between groups (all p > 0.05) except for image contrast which was lower for Saline-MRA group (GBCA-MRA 1.1 ± 0.4 vs Saline-MRA 1.8 ± 0.5; p < 0.001). Accuracy was high for both groups for reader 1/reader 2 for labrum (GBCA-MRA 94%/ 96% versus Saline-MRA 96%/93%; p > 0.999/p = 0.904) and acetabular (GBCA-MRA 86%/ 83% versus Saline-MRA 89%/87%; p = 0.902/p = 0.901) and femoral cartilage lesions (GBCA-MRA 97%/ 99% versus Saline-MRA 97%/97%; both p > 0.999).

Conclusion: Diagnostic accuracy and image quality of Saline-MRA and GBCA-MRA is high in assessing chondrolabral lesions underlining the potential role of non-gadolinium-based hip MRA.

Key points: • Image quality of Saline-MRA and GBCA-MRA was excellent for labrum, acetabular and femoral cartilage, ligamentum teres, and the capsule (all p > 0.18). • The overall image contrast was lower for Saline-MRA (Saline-MRA 1.8 ± 0.5 vs. GBCA-MRA 1.1 ± 0.4; p < 0.001). • Diagnostic accuracy was high for Saline-MRA and GBCA-MRA for labrum (96% vs. 94%; p > 0.999), acetabular cartilage damage (89% vs. 86%; p = 0.902), femoral cartilage damage (97% vs. 97%; p > 0.999), and extensive cartilage damage (97% vs. 93%; p = 0.904).

Keywords: Arthrography; Arthroscopy; Contrast agent; Hip; MRI.

Fig. 1

Flow diagram of patient inclusion

Fig. 2

A 40-year-old patient with preoperative GBCA-MR arthrogram showing an anterior labrum lesion (arrowhead) in the sagittal PD-w TSE image, (B) which could be confirmed arthroscopically (asterisk). Surgical images—L labrum, AC acetabular cartilage

Fig. 3

A 20-year-old patient with preoperative Saline-MR arthrogram with slightly lower image quality due to less bright joint fluid compared to Fig. 2. Despite that, an anterior labrum lesion (arrowhead) is clearly depicted in the sagittal PD-w TSE image, (B) which was confirmed arthoscopically (asterisk). Surgical images—AC acetabular cartilage

Fig. 4

A 36-year-old patient with preoperative GBCA-MR arthrogram showing an acetabular cartilage delamination in the radial PD-w TSE image (arrowhead), (B) which was confirmed arthroscopically (asterisk)

Fig. 5

A 27-year-old patient with preoperative Saline-MR arthrogram showing an acetabular cartilage delamination (arrowhead) in the radial PD-w TSE image, (B) which was confirmed arthroscopically (asterisk)

Fig. 6

A Right hip of a 35-year-old patient with preoperative GBCA-MR arthrogram. B Left hip of the same patient with Saline-MR arthrogram. Both axial-oblique images show femoral cartilage lesion (arrowheads) with similar overall image quality