Microperfusion-induced elevation of ADC is suppressed after contrast in breast carcinoma.
OBJECTIVE
To investigate the effect of gadolinium (Gd)-DTPA on the apparent diffusion coefficient (ADC) of breast carcinoma and to analyze the relationship between pre/postcontrast ADC and the degree of contrast enhancement.


METHODS
Nineteen histopathologically confirmed breast carcinomas (mean size = 22 mm) were analyzed. Their ADCs before and after contrast administration were measured. The contrast-to-noise ratios (CNRs) of the tumors were measured on fat-suppressed 3D T1-weighted images in precontrast, early, and late postcontrast phases. These results were correlated with the measured ADC values.


RESULTS
A significant decrease in the measured ADC was noted after contrast administration (-23%, P = 0.01). Lesions with relatively high ADC before contrast (>1.3 x 10(-3) mm(2)/sec; n = 12) demonstrated a larger degree of ADC reduction (mean 34%) than lesions with low ADC (< or =1.3 x 10(-3) mm(2)/sec; n = 7) (mean 4.5%). When an early postcontrast image was used as a surrogate marker of malignant potential, we found a significant inverse correlation with postcontrast ADC (gamma = -0.57, P = 0.02).


CONCLUSIONS
Postcontrast ADC exhibited lower values than precontrast ADC, which is thought to reflect suppression of the microperfusion-induced effect on diffusion-weighted imaging. Postcontrast ADC may be a better indicator than precontrast ADC to reflect malignant potential of tumors.
Yuen
Sachiko
S
Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. syuen@koto.kpu-m.ac.jp
Yamada
Kei
K
Goto
Mariko
M
Nishida
Kaori
K
Takahata
Akiko
A
Nishimura
Tsunehiko
T
D000465:Algorithms; D001943:Breast Neoplasms / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010477:Perfusion / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA