NIRA-07 COMPARISON OF DELAYED AND DOUBLE-DOSE MRI FOR DETECTION OF BRAIN METASTASES WITH GADOPICLENOL PRIOR TO STEREOTACTIC RADIOSURGERY
Josef Vymazal, Zuzana Ryznarova, Jiri Keller, Roman Liscak, Aaron RulsehAbstract
Purpose
To evaluate delayed imaging after single-dose (0.05 mmol/kg) and double-dose (0.1 mmol/kg) gadopiclenol (i.e. standard dose for other MR contrast agents) in the detection of brain metastases.
Methods
In this prospective single-center study, 156 subjects (73 female; mean age 63.8 ± 12.6 years) underwent MRI (3T, n = 152) prior to stereotactic radiosurgery. T1-weighted 3D SPACE sequences were used for all evaluations. All subjects had standard postcontrast acquisitions with the recommended dose of gadopiclenol (0.05 mmol/kg). Delayed imaging was additionally performed after roughly 13 minutes; half of subjects received an additional dose of gadopiclenol prior to the delayed imaging (delayed double dose [DDD], n = 81), while the remaining subjects did not (delayed single dose [DSD], n = 78). Three blinded neuroradiologists independently evaluated all scans across 4 sessions minimally 4 weeks apart. Lesion coordinates were spatially clustered and classified under strict (unanimous) and majority (2-of-3) reference standards. Signal intensity ratios were evaluated in a subset of lesions (normalized to normal-appearing white matter [NAWM]).
Results
A total of 1,035 consensus and 1,335 majority-detected lesions were identified; median consensus lesion diameter was 7 mm (IQR 4–15). Among consensus lesions, 41% were ≤5 mm. DDD imaging detected significantly more consensus lesions than standard non-delayed (255 vs. 215, p < 0.001), while DSD imaging did not (287 vs. 278, p = 0.48). The DDD upstaging-to-downstaging ratio was 2.9:1 versus 1.1:1 for DSD. The DDD detection advantage was predominantly driven by small lesions: 79% of additional majority-detected lesions on DDD scans were ≤5 mm. The lesion-to-NAWM ratio increased 18% on DDD scans (1.83 to 2.13, p < 0.001) but was unchanged with DSD (p = 0.70). The DDD benefit was uniform across all readers with no significant reader×dose interaction.
Conclusion
DDD gadopiclenol significantly improves detection of small brain metastases and enhances lesion-to-tissue contrast, supporting its use in pre-radiosurgery planning.