Breast diffusion-weighted MRI: comparison of tetrahedral versus orthogonal diffusion sensitization for detection and localization of mass lesions.

PURPOSE

To evaluate the potential of tetrahedral diffusion-weighted imaging (DWI) compared to orthogonal DWI for detection and localization of early enhanced breast mass lesions at 1.5T.

MATERIALS AND METHODS

Sixty-seven consecutive patients (mean age 51.7 years, range 14-84 years) with 68 solitary early enhanced breast lesions suspicious for cancer on dynamic contrast-enhanced magnetic resonance imaging (MRI) were enrolled in this retrospective study. Two radiologists independently observed maximum intensity projection images of orthogonal and tetrahedral DWI and the diagnostic accuracy and background tissue visibility between two DWI techniques were compared. Contrast-enhanced MRI was used as the reference standard. Background tissue visibility was assessed based on whether the "breast quadrant" and "skin line" were determined. A phantom validation study for apparent diffusion coefficient (ADC) values was also conducted.

RESULTS

Sensitivity (93%) and specificity (96%) on tetrahedral DWI were equivalent to those on orthogonal DWI (sensitivity, 88%; specificity, 95%). Background tissue was more easily determined with tetrahedral DWI (breast quadrant, 90%; skin lines, 95%) than with orthogonal DWI (breast quadrant, 61%; skin lines, 16%). ADC values of tetrahedral DWI were highly correlated with those of orthogonal DWI.

CONCLUSION

Tetrahedral DWI provided equivalent detectability of mass lesions with improved visibility of surrounding anatomical structure.