The Study Of The Value Of Dynamic Contrast-enhanced MR Imaging, DWI, And Single-voxel ～1H MR Spectroscopy In The Diagnosis Of Breast Carcinoma

Objective: To evaluate the diagnostic effectiveness of dynamic contrast-enhanced MR imaging (DCE-MRI), diffusion-weighted imaging (DWI), and single-voxel ~1H MR spectroscopy (MRS) in patients with breast cancer.Methods: 155 Patients with breast lesions detected by physical examination or mammography underwent MR examinations on a 1.5 T scanner (GE, Signa Excite II) pre-operatively. MR examinations included 8min 3D DCE-MRI by VIBRANT sequence, DWI with b value of 0, 500, and 1000 s/mm~2 by single-shot EPI sequence, and single-voxel ~1H MRS by J-PRESS and Spectral Spatial PRESS. Contrast agent Gd-DTPA was injected with bolus and was followed with a 20-mL flush of isotonic saline solution. Results were correlated with histopathologic findings. DCE-MRI time-intensity curves of the lesions were classified as type I (no enhancement), type II (steady enhancement), type III (plateau), and type IV (washout). Lesions with type I or type II were classified as benign, whereas the lesions with type III or type IV were classified as malignant. The mean apparent diffusion coefficients (ADC) of the lesions were calculated on DWI with both b value of 500 s/mm~2 and 1000 s/mm~2. Lesions presenting a detectable Choline signal in their spectra at 3.2 ppm werediagnosed as malignant. The sensitivity, specificity, and accuracy of DCE-MRI, DWI, and single-voxel 'H MRS regarding the diagnosis of breast cancer were determined respectively. ROC curves were used to identify the cutoff to differentiate the malignant and benign lesions.Results: Among 155 patients, histology revealed 86 malignant and 69 benign lesions. The sensitivity and specificity of DCE-MRI were 89.5% and 66.0%. ROC curves were generated in order to determine the ADC thresholds that could balance the needs of sensitivity and specificity. We selected the ADC cutoff value of 1.11 x 10'3 mm2/s for b=1000 s/mm2 and 1.57 x 10"3 mm2/s for b= 500 s/mm2. At the cutoff values, sensitivity and specificity were 73.6% and 80.0% for b=1000 and 83.3% and 56.9% for b=500 s/mm2. For MRS, the sensitivity and specificity were 41.9% and 91.2%. In the study the rADC was used to try to partially eliminate the variances among different individuals for the first time and revealed better accuracy than absolute ADC. The rADC cutoff was 0.89. At the cutoff value, the sensitivity and specificity were 81.6% and 63.2%. The sensitivity of DCE-MRI is the highest, but the specificity of MRS and ADC of b= 1000 s/mm2 is higher than that of DCE-MRI (7><0.05). The difference of the accuracy among the DCE-MRI, DWI, and MRS showed however no statistical significance (P >0.05).Conclusion: DCE-MRI is the most essential method in the MR imaging ofbreast. DWI and MRS can provide the functional and cytologic information of breast tumor. Due to its short scan time and no need of contrast agent, DWI is an easy and effective method for breast cancer diagnosis compared with DCE-MRI. The accuracy of ADC with high b-value (b=1000s/mm2) is promising. MR spectroscopy couldcomplement MR imaging findings to improve the specificity, but limited by technics and the pathologic types of tumors. DWI and MRS have effective value in the diagnosis of breast tumor, but could not replace DCE-MRI. Combination of DCE-MRI, DWI, and single-voxel !H MRS could give more information in differentiating breast lesions and reduce the number of unnecessary biopsies.