Comparison of blood pool and extracellular gadolinium chelate for functional MR evaluation of vascular thoracic outlet syndrome.

OBJECTIVE: To compare performance of single-injection blood pool agent (gadofosveset trisodium, BPA) against dual-injection extracellular contrast (gadopentetate dimeglumine, ECA) for MRA/MRV in assessment of suspected vascular TOS.

MATERIALS AND METHODS: Thirty-one patients referred for vascular TOS evaluation were assessed with BPA (n=18) or ECA (n=13) MRA/MRV in arm abduction and adduction. Images were retrospectively assessed for: image quality (1=non-diagnostic, 5=excellent), vessel contrast (1=same signal as muscle, 4=much brighter than muscle) and vascular pathology by two independent readers, with a separate experienced reader providing reference assessment of vascular pathology.

RESULTS: Median image quality was diagnostic or better (score ≥ 3) for ECA and BPA at all time points, with BPA image quality superior at abduction late (BPA 4.5, ECA 4, p=0.042) and ECA image quality superior at adduction-early (BPA 4.5; ECA 4.0, p=0.018). High qualitative vessel contrast (mean score ≥ 3) was observed at all time points with both BPA and ECA, with superior BPA vessel contrast at abduction-late (BPA 3.97 ± 0.12; ECA 3.73 ± 0.26, p=0.007) and ECA at adduction-early (BPA 3.42 ± 0.52; ECA 3.96 ± 0.14, p<0.001). Readers readily identified arterial and venous pathology with BPA, similar to ECA examinations.

CONCLUSION: Single-injection BPA MRA/MRV for TOS evaluation demonstrated diagnostic image quality and high vessel contrast, similar to dual-injection ECA imaging, enabling identification of fixed and functional arterial and venous pathology.