Non-contrast enhanced MRI for evaluation of breast lesions: comparison of non-contrast enhanced high spectral and spatial resolution (HiSS) images versus contrast enhanced fat-suppressed images

Abstract

Rationale and objectives: The aims of this study were to evaluate high spectral and spatial resolution (HiSS) magnetic resonance imaging (MRI) for the diagnosis of breast cancer without the injection of contrast media by comparing the performance of precontrast HiSS images to that of conventional contrast-enhanced, fat-suppressed, T1-weighted images on the basis of image quality and in the task of classifying benign and malignant breast lesions.

Materials and methods: Ten benign and 44 malignant lesions were imaged at 1.5 T with HiSS (precontrast administration) and conventional fat-suppressed imaging (3-10 minutes after contrast administration). This set of 108 images, after randomization, was evaluated by three experienced radiologists blinded to the imaging technique. Breast Imaging Reporting and Data System morphologic criteria (lesion shape, lesion margin, and internal signal intensity pattern) and final assessment were used to measure reader performance. Image quality was evaluated on the basis of boundary delineation and quality of fat suppression. An overall probability of malignancy was assigned to each lesion for HiSS and conventional images separately.

Results: On boundary delineation and quality of fat suppression, precontrast HiSS scored similarly to conventional postcontrast MRI. On benign versus malignant lesion separation, there was no statistically significant difference in receiver-operating characteristic performance between HiSS and conventional MRI, and HiSS met a reasonable noninferiority condition.

Conclusions: Precontrast HiSS imaging is a promising approach for showing lesion morphology without blooming and other artifacts caused by contrast agents. HiSS images could be used to guide subsequent dynamic contrast-enhanced MRI scans to maximize spatial and temporal resolution in suspicious regions. HiSS MRI without contrast agent injection may be particularly important for patients at risk for contrast-induced nephrogenic systemic fibrosis or allergic reactions.

Figure 1

A 69 year old woman with an invasive ductal carcinoma lesion was imaged using HiSS and conventional imaging. a) HiSS water peak height (TR/TE = 500/90 ms, in-plane resolution 1 mm) and b) conventional T1-weighted (TR/TE = 12.6/3.8 ms, in-plane resolution 1 mm) sagittal images are shown. The lesion is indicated with an arrow. Spiculations surrounding the lesion are much better visualized in the HiSS image, probably due to contrast agent diffusion from the lesion in the DCEMRI image.

Figure 2

A 53 year old woman with an atypical ductal hyperplasia lesion was imaged using HiSS and conventional imaging. a) HiSS water peak height (TR/TE = 500/192 ms, in-plane resolution 1 mm) and b) conventional T1-weighted (TR/TE = 175/4.2 ms, in-plane resolution 1 mm) sagittal images are shown. The lesion is indicated with an arrow. Fat suppression is superior in the HiSS image.

Figure 3

A 44 year old woman with a cancerous lesion and lymph node invasion (not shown) was imaged using HiSS and conventional imaging. a) HiSS water peak height (TR/TE = 250/96 ms, in-plane resolution 0.63 mm) and b) conventional T1-weighted (TR/TE = 175/4.2 ms, in-plane resolution 1 mm) sagittal images are shown. The lesion is indicated with an arrow. Fat suppression is superior in the HiSS image.

Figure 4

Boxplots for probability of malignancy distribution are shown for benign and malignant lesions, for conventional T1-weighted and HiSS images. Both conventional and HiSS imaging methods show a statistically significant separation of benign and malignant lesions (p < 0.001), but this appears to be more obvious in HiSS data. The differences in the mean of the probability distribution between conventional and HiSS images were statistically significant for both benign and malignant lesions (p < 0.05).

Figure 5

ROC plots with probability of malignancy as a classifier, and proper binormal model fits to the data, are shown for conventional T1-weighted (solid circles, dotted line) and HiSS (open circles, solid line) images. The AUC values for conventional and HiSS images are 0.81 and 0.84 respectively (difference 0.036, 95% CI: (−0.25;0.32)) for reader A, 0.86 and 0.83 (difference −0.028, 95% CI: (−0.26;0.20) for reader B, and 0.76 and 0.91 (difference 0.16, 95% CI: (0.02;0.30) for reader C. There is no statistically significant difference in the overall performance of the two imaging methods.