Differential diagnosis of mammographically and clinically occult breast lesions on diffusion-weighted MRI

• Published in: Journal of magnetic resonance imaging 2010-03, Vol.31 (3), p.562-570
• Main Authors: Partridge, Savannah C., DeMartini, Wendy B., Kurland, Brenda F., Eby, Peter R., White, Steven W., Lehman, Constance D.
• Format: Article
• Language: English
• Subjects: Adult; Aged; apparent diffusion coefficient (ADC); benign lesions; breast cancer; Breast Neoplasms - diagnosis; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging - methods; diffusion-weighted imaging (DWI); Female; Humans; mammographically occult; Mammography - methods; Middle Aged; nonpalpable; Young Adult
• ISSN: 1053-1807; 1522-2586
• DOI: 10.1002/jmri.22078

Purpose: To investigate the diagnostic performance of diffusion‐weighted imaging (DWI) for mammographically and clinically occult breast lesions. Materials and Methods: The study included 91 women with 118 breast lesions (91 benign, 12 ductal carcinoma in situ [DCIS], 15 invasive carcinoma) initially detected on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and assigned BI‐RADS category 3, 4, or 5. DWI was acquired with b = 0 and 600 s/mm2. Lesion visibility was assessed on DWI. Apparent diffusion coefficient (ADC) values were compared between malignancies, benign lesions, and normal (no abnormal enhancement on DCE‐MRI) breast tissue, and the diagnostic performance of DWI was assessed based on ADC thresholding. Results: Twenty‐four of 27 (89%) malignant and 74/91 (81%) benign lesions were hyperintense on the b = 600 s/mm2 diffusion‐weighted images. Both DCIS (1.33 ± 0.19 × 10−3 mm2/s) and invasive carcinomas (1.30 ± 0.27 × 10−3mm2/s) were lower in ADC than benign lesions (1.71 ± 0.43 × 10−3mm2/s; P < 0.001), and each lesion type was lower in ADC than normal tissue (1.90 ± 0.38 × 10−3mm2/s, P ≤ 0.001). Receiver operating curve (ROC) analysis showed an area under the curve (AUC) of 0.77, and sensitivity = 96%, specificity = 55%, positive predictive value (PPV) = 39%, and negative predictive value (NPV) = 98% for an ADC threshold of 1.60 × 10−3mm2/s. Conclusion: Many mammographically and clinically occult breast carcinomas were visibly hyperintense on diffusion‐weighted images, and ADC enabled differentiation from benign lesions. Further studies evaluating DWI while blinded to DCE‐MRI are necessary to assess the potential of DWI as a noncontrast breast screening technique. J. Magn. Reson. Imaging 2010;1:562–570. © 2010 Wiley‐Liss, Inc.