Diffusion-weighted magnetic resonance imaging of breast lesions: first experiences at 3 T.
OBJECTIVE
Dynamic contrast-enhanced magnetic resonance imaging (MRI) has been established as a valuable tool for the detection of breast cancer. There is evidence suggesting that diffusion-weighted imaging (DWI) may be useful to distinguish between malignant and benign breast lesions. We seek to evaluate the ability of DWI to differentiate between malignant and benign breast lesions at 3 T.


METHODS
Dynamic contrast-enhanced MRI and DWI of the breasts were performed in 31 female patients (age: mean, 46 years; range, 34-69 years) with suspected breast lesions on mammography and ultrasound using a 3-T scanner (MAGNETOM Tim Trio; Siemens Medical Solutions, Erlangen, Germany). Each lesion was assigned as either malignant or benign, blinded to the results of mammography and ultrasound, according to their imaging characteristics on contrast-enhanced MRI, DWI, and apparent diffusion coefficient (ADC) measurements. Tissue samples were obtained from all lesions by either needle or excision biopsy. Using histological results as the gold standard, the diagnostic accuracies of the dynamic contrast-enhanced MRI, DWI, and ADC were calculated and compared.


RESULTS
All breast lesions (n = 31) were identified on both the dynamic contrast-enhanced MRI and DWI scans. The threshold ADC value was determined to be 0.00121 mm2/s, below which a lesion was considered malignant. The sensitivities/specificities of the dynamic contrast-enhanced MRI, qualitative DWI, and quantitative ADC were 95%/91%, 95%/63.6%, and 90%/91%, respectively. The differences in sensitivities, specificities, positive and negative predictive values, and diagnostic accuracies between the 3 examinations were statistically insignificant.


CONCLUSIONS
Diffusion-weighted imaging at 3 T is highly sensitive in the detection of malignant breast lesions even with qualitative assessment alone, whereas ADC measurement offers quantitative assessment and increases the specificity to more than 90%. Further studies involving a larger cohort size and a wider spectrum of breast lesions are indicated.
Lo
Gladys G
GG
Department of Diagnostic and Interventional Radiology, Hong Kong Sanatorium and Hospital, 2 Village Road, Happy Valley, Hong Kong. drgl@hksh.com
Ai
Victor
V
Chan
John K F
JK
Li
K W
KW
Cheung
Polly S Y
PS
Wong
T T
TT
Ma
Micheal
M
Lee
Raymond
R
Chien
Daisy
D
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA