The role of parallel diffusion-weighted imaging and apparent diffusion coefficient (ADC) map values for evaluating breast lesions: preliminary results

Abstract

Rationale and objectives: To evaluate the feasibility of using diffusion-weighted imaging (DWI) with an array spatial sensitivity encoding technique (ASSET) and apparent diffusion coefficient (ADC) map values with different b values to distinguish benign and malignant breast lesions.

Materials and methods: Fifty-six female patients with 60 histologically proven breast lesions and 20 healthy volunteers underwent magnetic resonance imaging. A subset of normal volunteers (n = 7) and patients (n = 16) underwent both conventional DWI and ASSET-DWI, and the image quality between the two methods was compared. Finally, ASSET-DWI with b = 0, 600 s/mm(2), and b = 0, 1000 s/mm(2), were compared for their ability to distinguish benign and malignant breast lesions.

Results: The ASSET-DWI method had less distortion, fewer artifacts, and a lower acquisition time than other methods. No significant difference (P > .05) was detected in ADC map values between ASSET-DWI and conventional DWI. For ASSET-DWI, the sensitivity of ADC values for malignant lesions with a threshold of less than 1.44 x 10(-3) mm(2)/s (b = 600 s/mm(2)) and 1.18 x 10(-3) mm(2)/s (b = 1000 s/mm(2)) was 80% and 77.5%, respectively. The specificity of both groups was 95%.

Conclusion: ASSET-DWI evaluation of breast tissue offers decreased distortion, susceptibility to artifacts, and acquisition time relative to other methods. The use of ASSET-DWI is feasible with b values ranging from 600 to 1000 s/mm(2) and provides increased specificity compared to other techniques. Thus, the ADC value of a breast lesion can be used to further characterize malignant lesions from benign ones.

Copyright 2010 AUR. Published by Elsevier Inc. All rights reserved.

Figures

Fig. 1

A 43-year-old woman with invasive ductal carcinoma in the right breast. (a) The SE T1WI axial scan showed a slightly hypointense lesion in the right breast. (b) Dynamic contrast magnetic resonance imaging revealed the enhaned lesion. The lesion showed distortion on traditional DWI (b = 0, 1000 s/mm2) (c) compared with SE T1WI (a) on the same slice, but the distortion was decreased with ASSET-DWI (b = 0, 1000 s/mm2) (d).

Fig. 2

The comparison of SNR (a) and CNR (b) between the conventional DWI and ASSET-DWI.

Fig.3

A 29-year-old woman with invasive ductal carcinoma in the right breast. (a) A mass found in the right breast was hypointense on the axial SE T1WI. (b) The lesion exhibited a slightly high signal intensity on axial T2WI STIR. (C) The lesion was obviously enhanced but with an ill-defined margin on the dynamic contrast image. (d) The lesion showed high signal intensity on ASSET-DWI (b = 1000 s/mm2).

Fig.4

A 53-year-old woman with fibroadenoma in the right breast. (a) A mass found in the right breast was hypointense on the axial SE T1-WI. (b) The lesion showed high signal intensity on axial T2WI STIR. (C) The lesion was enhanced with a well-defined margin on the dynamic contrast image. (d) The lesion showed slightly high signal on ASSET-DWI (b = 1000 s/mm2).

Fig. 5

An 80-year-old woman with mucinous adenocarcinoma in the left breast. (a) A mass found in the left breast showed low signal intensity on the axial SE T1WI. (b) The lesion showed high signal intensity on axial T2WI STIR. (c) The ADC color map showed that the ADC map value of the lesion was 2.59 × 10−3 mm2/s (b = 1000 s/mm2). (d) The pathological image of the tumor after resection (HE staining × 40). The low density of tumor cells and a large amount of mucus around the tumor cells which reflected a ‘mucoid lake’ were observed.