Accuracy of MR spectroscopy and MR diffusion technique in diagnosing female breast tumors

Abstract

Magnetic Resonance Spectroscopy (MRS) and Diffusion Techniques (DWI) are currently being used more extensively than conventional Magnetic Resonance Imaging (MRI) in diagnosing lesions, therefore the main objective of this study was to evaluate the accuracy of MRS and DWI in characterization of female breast cancer. The data was collected from 100 patients with breast lesions in Saudi German Hospital using MRS and DWI. MRI was performed using a 1.5-T system (Magnetom symphony 1.5 Tesla, Siemens-Germany). For Magnetic Resonance Spectroscopy a Single-voxel MRS (SVS) was applied using a Point- resolved Spectroscopy Sequence (PRESS). All patients underwent diffusion weighted images with b values, 500, 1,000, 1,500, 2,000, and 3,000 s/mm 2. Apparent Diffusion Coefficient (ADC) values were generated automatically through soft-ware system. If a high-signal-intensity lesion was detected in high- b-value (b = 3,000 s/mm2) images, that lesion was defined as malignant. We observed that the signal-intensity of benign lesion disappeared in the high-b- value (b = 3,000 s/mm2) and continue in brightness in case of malignant. The ADC values of the mass was calculated from two different gradient factors (b 1 = 500 s/mm2 and b2 = 1,500 s/mm2) for positive results. For the in vivo MRS studies, each spectrum was evaluated for the presence of choline based on consensus reading, the results of this study showed that the sensitivity, specificity and accuracy of MRS were 100%, 90% and 93% respectively. For DWI, lesions with ADC values (> 1.5 mm2/s) were considered benign where as lesions with ADC values (< 1 mm2/s) were considered malignant, those lesions with ADC values (>1–<1.5 mm2/s) represented the overlap cases (between benign and malignant). This method of using ADC values for the detection of malignant lesions showed a sensitivity, specificity and accuracy of 96%, 86% and 89% respectively. In conclusion MR spectroscopy was useful for characterizing breast lesions measuring 1.5 cm or larger and diffusion-weighted imaging was useful for characterizing small and large lesions despite of overlap in some cases.