Intraindividual Comparison of Ultrafast versus Standard Two-dimensional Dynamic Contrast-enhanced Breast MRI.

Background Ultrafast breast MRI promises to improve conspicuity of cancers by avoiding masking due to background parenchymal enhancement (BPE) and to improve classification of enhancing lesions. However, published studies systematically penalized standard dynamic contrast-enhanced (DCE) MRI because they integrated ultrafast MRI into existing DCE protocols, such that postcontrast acquisitions of DCE MRI began only after completion of ultrafast MRI. Purpose To perform an intraindividual comparison of conspicuity and classification of enhancing breast lesions with ultrafast MRI versus standard DCE MRI, where both methods included the early postcontrast phase. Materials and Methods This was a retrospective analysis of 31 women (median age, 48 years [IQR, 39-51 years]) from September 2021 to January 2023. Women underwent DCE MRI at 1.5 T and, within 2 days, a second contrast-enhanced examination using ultrafast MRI, for further diagnostic assessment of difficult-to-interpret enhancing lesions and/or BPE. For DCE MRI, a two-dimensional gradient-echo series (0.61 × 0.61 × 3.0-mm spatial resolution, 60 seconds per dynamic frame) was obtained once before and four times after injection of 0.1 mmol/kg gadobutrol. For ultrafast MRI, a compressed-sense accelerated three-dimensional gradient-echo series (0.92 × 0.97 × 2.5-mm spatial resolution, 4 seconds per keyhole dynamic frame) was obtained over 90 seconds before, during, and after injection of 0.1 mmol/kg gadobutrol. Two breast radiologists independently rated BPE, image quality, and conspicuity and morphology of enhancing lesions, and enhancement kinetics were analyzed (ultrafast MRI: maximum slope and time to enhancement; DCE MRI: wash-in rate and time course pattern). Results A total 59 enhancing lesions were reported in the 62 breasts of the 31 patients. BPE ratings were on average 0.8 points lower at ultrafast versus DCE MRI (mean, 2.5 ± 1.2 [SD] vs 3.3 ± 1.2; P < .001). Despite this mild reduction in BPE, lesion conspicuity was rated lower at ultrafast than at DCE MRI (mean, 3.5 ± 1.3 vs 4.1 ± 1.0; P = .001), as was image quality (mean, 2.3 ± 0.9 vs 4.1 ± 0.8; P < .001). Lesion morphology (shape, margin, internal architecture) was less assessable at ultrafast MRI (all P < .05). Kinetic parameters derived from ultrafast MRI did not improve classification of enhancing lesions compared with those derived from DCE MRI: At ultrafast MRI, time to enhancement was shorter for malignant versus benign lesions (P = .01), but maximum slope did not differ, whereas at DCE MRI, both wash-in rate and time course pattern differed between malignant and benign lesions (both P = .01). Conclusion In this enriched cohort in which ultrafast MRI was expected to provide diagnostic advantages over DCE MRI, ultrafast MRI in fact led to reduced lesion conspicuity and did not improve lesion classification. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Cotes and Jacobs in this issue.