Diffusion-tensor imaging as an adjunct to dynamic contrast-enhanced MRI for improved accuracy of differential diagnosis between breast ductal carcinoma in situ and invasive breast carcinoma

Abstract

Objective: To determine the value of diffusion-tensor imaging (DTI) as an adjunct to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for improved accuracy of differential diagnosis between breast ductal carcinoma in situ (DCIS) and invasive breast carcinoma (IBC).

Methods: The MRI data of 63 patients pathologically confirmed as breast cancer were analyzed. The conventional MRI analysis metrics included enhancement style, initial enhancement characteristic, maximum slope of increase, time to peak, time signal intensity curve (TIC) pattern, and signal intensity on FS-T2WI. The values of apparent diffusion coefficient (ADC), directionally-averaged mean diffusivity (Davg), exponential attenuation (EA), fractional anisotropy (FA), volume ratio (VR) and relative anisotropy (RA) were calculated and compared between DCIS and IBC. Multivariate logistic regression was used to identify independent factors for distinguishing IBC and DCIS. The diagnostic performance of the diagnosis equation was evaluated using the receiver operating characteristic (ROC) curve. The diagnostic efficacies of DCE-MRI, DWI and DTI were compared independently or combined.

Results: EA value, lesion enhancement style and TIC pattern were identified as independent factor for differential diagnosis of IBC and DCIS. The combination diagnosis showed higher diagnostic efficacy than a single use of DCE-MRI (P=0.02), and the area of the curve was improved from 0.84 (95% CI, 0.67-0.99) to 0.94 (95% CI, 0.85-1.00).

Conclusions: Quantitative DTI measurement as an adjunct to DCE-MRI could improve the diagnostic performance of differential diagnosis between DCIS and IBC compared to a single use of DCE-MRI.

Keywords: Breast carcinoma in situ; breast; diffusion tensor imaging; magnetic resonance imaging.

Figure 1

ROC curve showed the performance of DCE-MRI alone, DTI alone (used EA value), and combination of the two to differentiate DCIS and IBC. B =600×10⁻³ s/mm². ROC, receiver operating characteristic; DCE-MRI, dynamic contrast-enhanced magnetic resonance imaging; DTI, diffusion-tensor imaging; DCIS, breast ductal carcinoma in situ; IBC, invasive breast carcinoma.

Figure 2

A 50-year-old woman with invasive ductal carcinoma (IDC) grade II in the right breast which was misdiagnosed as DCIS by a single use of DCE-MRI but it was correctly diagnosed by combination diagnosis of DTI and DCE-MRI. (A) Sagittal view on FS-T2 weighted image; (B) Sagittal view of DCE MR, the green square showed the ROI position; (C) TIC curve pattern; (D) Axial contrast-enhanced image obtained in delayed phase after contrast injection; (E) On DWI map with a b value of 600 s/mm²; (F) Color-coded EA map with the EA value of 0.62. The lesion can be easily identified compared to the adjacent normal breast tissue from above images. When 13.67 was used as a cut-off value of combination equation, the Y value (16.59) of the lesion was larger than it. It prompted that the lesion was more likely to be IBC. Consequently, this result was verified by final pathology. DCIS, breast ductal carcinoma in situ; DTI, diffusion-tensor imaging; DCE-MRI, dynamic contrast-enhanced magnetic resonance imaging; ROI, region of interest; TIC, time signal intensity curve; DWI, diffusion weighted imaging; IBC, invasive breast carcinoma.

Figure 3

A 40-year-old woman with invasive ductal carcinoma (IDC) grade I in the left breast which was misdiagnosed as DCIS by a single use of DCE-MRI but it was correctly diagnosed by combination diagnosis. (A) Sagittal view on FS-T2 weighted image; (B) Sagittal view of DCE MR and ROI position; (C) TIC curve pattern; (D) Axial contrast-enhanced image obtained in delayed phase after contrast injection; (E) A 600 s/mm² DWI map; (F) Color-coded EA map with EA value of 0.436. The lesion was identified as a hyperintensity area along the mammary duct on DCE-MRI. When a cut-off value of 13.67 was used for combination diagnosis equation, the Y value (13.68) of the lesion was larger than it. It was correctly diagnosed as IBC by combination diagnosis equation. DCIS, breast ductal carcinoma in situ; DCE-MRI, dynamic contrast-enhanced magnetic resonance imaging; ROI, region of interest; TIC, time signal intensity curve; DWI, diffusion weighted imaging; IBC, invasive breast carcinoma.