Background: To evaluate the performance of an abbreviated dynamic contrast-enhanced MR imaging (MRI) protocol for breast cancer detection; a comparison with the complete diagnostic protocol has been conducted.
Methods: A retrospective analysis on 508 patients was performed. Abbreviated protocol (AP) included one pre-contrast and the first post-contrast T1-weighted series. Complete protocol (CP) consisted of four post-contrast and one pre-contrast T1-weighted series. Diagnostic performance was assessed for AP and CP. Performance comparison was made using McNemar's test for sensitivity and specificity and Moskowitz and Pepe's method as regards negative predictive value (NPV) and positive predictive value (PPV). AP has been realized in two different ways (AP1 and AP2) and they were compared by means of Cohen's κ.
Results: Both CP and AP revealed 206 of 207 cancers. There were no statistically significant differences between AP and CP diagnostic performance (P > 0.05). NPVs of CP and both versions of AP (99.57 vs. 99.56%, P = 0.39), as well as the specificity (77.08 vs. 75.42%, P = 0.18), were substantially equivalent. Relative predictive value method did not reveal the presence of a statistically significant difference between the PPV of CP and both versions of AP (74.91 vs. 73.57%, P = 0.099). Analysis for single lesion confirmed that both CP and AP had equivalent results: CP and AP revealed 280 of 281 malignancies. NPVs of CP and both AP versions, as well as the specificity (P > 0.05), were substantially equivalent. Relative predictive value method did not reveal the presence of a significant difference between the PPV of CP and both AP versions (70.89 vs. 70.18%, P = 0.25; 70.89 vs. 70.00%, P = 0.13).
Conclusions: Abbreviated approach to breast MRI examination reduces the image acquisition and the reading time associated with MR substantially without influencing the diagnostic accuracy (high sensitivity and NPV >99.5%). AP could translate into cost-savings and could enable a higher number of examinations within the same MR session.
Keywords: Abbreviated protocol; Breast cancer; Complete protocol; DCE-MRI.