The added value of quantitative multi-voxel MR spectroscopy in breast magnetic resonance imaging

Abstract

Objective To determine whether quantitative multivoxel MRS improves the accuracy of MRI in the assessment of breast lesions. Methods Twenty-five consecutive patients with 26 breast lesions ≥1 cm assessed as BI-RADS 3 or 4 with mammography underwent quantitative multivoxel MRS and contrast-enhanced MRI. The choline (Cho) concentration was calculated using the unsuppressed water signal as a concentration reference. ROC analysis established the diagnostic accuracy of MRI and MRS in the assessment of breast lesions. Results Respective Cho concentrations in 26 breast lesions re-classified by MRI as BI-RADS 2 (n=5), 3 (n=8), 4 (n= 5) and 5 (n=8) were 1.16±0.43 (mean±SD), 1.43±0.47, 2.98±2.15 and 4.94±3.10 mM. Two BI-RADS 3 lesions and all BI-RADS 4 and 5 lesions were malignant on histopathology and had Cho concentrations between 1.7 and 11.8 mM (4.03±2.72 SD), which were significantly higher (P=0.01) than that in the 11 benign lesions (0.4- 1.5 mM; 1.19±0.33 SD). Furthermore, Cho concentrations in the benign and malignant breast lesions in BI-RADS 3 category differed (P=0.01). The accuracy of combined multivoxel MRS/breast MRI BI-RADS re-classification (AUC= 1.00) exceeded that of MRI alone (AUC=0.96±0.03). Conclusions These preliminary data indicate that multivoxel MRS improves the accuracy of MRI when using a Cho concentration cut-off ≤1.5 mM for benign lesions. Key Points • Quantitative multivoxel MR spectroscopy can improve the accuracy of contrast-enhanced breast MRI. • Multivoxel-MRS can differentiate breast lesions by using the highest Cho-concentration. • Multivoxel-MRS can exclude patients with benign breast lesions from further invasive diagnostic procedures. © The Author(s) 2011.