Multiparametric evaluation of breast lesions using PET-MRI: initial results and future perspectives

Abstract

The purpose of this study was to evaluate the diagnostic accuracy of multiparametric evaluation of breast lesions combining information of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted imaging (DWI), and F-fluoro-deoxi-glucose (F-FDG) positron emission tomography/computed tomography (PET-CT). After approval of the institutional research ethics committee, 31 patients with suspicious breast lesions on MRI performed F-FDG PET-CT with a specific protocol for breast evaluation. Patients' mean age was 47.8 years (range, 29-77 years). Positron emission tomography and magnetic resonance imaging (PET-MRI) images were fused. A lesion was considered positive on multiparametric evaluation if at least 1 of the following was present: washout/type 3 kinetic curve on DCE-MRI, restricted diffusion on DWI with minimum apparent diffusion coefficient value <1.00 × 10 mm/s, and abnormal metabolism on F-FDG PET-CT (higher than the physiologic uptake of the normal breast parenchyma). Thirty-eight lesions with histologic correlation were evaluated on the 31 included patients, being 32 mass lesions (84.2%), and 6 nonmass lesions (15.8%). Lesions' mean diameter was 31.1 mm (range, 8-94 mm). Multiparametric evaluation provided 100% sensitivity, 55.5% specificity, 87.9% positive predictive value, 100% negative predictive value, and 89.5% accuracy, with 29 true-positives results, 5 true-negatives, 4 false-positives, and no false-negative results. Multiparametric evaluation with PET-MRI functional data showed good diagnostic accuracy to differentiate benign from malignant breast lesions, reducing the number of unnecessary biopsies, without missing any diagnosis of cancer in our case series.

FIGURE 1

A 63-year-old female patient with a probably benign mass on conventional breast examinations. MRI showed a lobulated mass in the right breast (A). DCE-MRI showed an indeterminate plateau-type kinetic curve (B). The lesion showed high signal on DWI (C) and a small decrease in signal intensity on ADC map (D), ADC = 1.50 × 10⁻³ mm²/s, suggestive of benign lesion. PET-MRI fusion showed increased ¹⁸F-FDG uptake (E), suggestive of malignant lesion. Percutaneous biopsy was compatible with mucinous carcinoma. ¹⁸F-FDG = ¹⁸F-fluoro-deoxi-glucose, ADC = apparent diffusion coefficient, DCE-MRI = dynamic contrast-enhanced magnetic resonance imaging, DWI = diffusion-weighted imaging, PET-MRI = positron emission tomography and magnetic resonance imaging.

FIGURE 2

A 57-year-old female patient with a proven IDC in the right breast. Preoperative MRI showed a small mass on the left breast (A). DCE-MRI showed a progressive-type kinetic curve (B), suggestive of benign lesion. The lesions showed high signal on DWI (C) and low signal on ADC map (D), ADC = 0.84 × 10⁻³ mm²/s, suggestive of malignant lesion. PET-MRI fusion showed no increase of ¹⁸F-FDG uptake on the lesion (E), suggestive of benign lesion. After surgical resection, the histologic diagnosis was low-grade IDC. ¹⁸F-FDG = ¹⁸F-fluoro-deoxi-glucose, ADC = apparent diffusion coefficient, DCE-MRI = dynamic contrast-enhanced magnetic resonance imaging, DWI = diffusion-weighted imaging, IDC = invasive ductal carcinoma, PET-MRI = positron emission tomography and magnetic resonance imaging.