Influence of post-treatment delay on the evaluation of the response to focused ultrasound surgery of breast cancer by dynamic contrast enhanced MRI.
The assessment of the effectiveness of MRI-guided focused ultrasound surgery (MRIgFUS) of breast carcinomas can be performed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters which monitor the presence of residual tumour. The aim of this study was to evaluate the effect of the post-treatment delay on this assessment. DCE-MRI data were acquired immediately and 3-14 days after MRIgFUS treatment of 26 tumours (<7 days, n = 6; = or > ge;7 days, n = 20). The percentage of residual tumour was determined histologically on the resected mass and correlated with two DCE-MRI parameters: increase in signal intensity (ISI) and positive enhancement integral (PEI). No correlation could be found between DCE-MRI data acquired immediately after treatment and the percentage of residual tumour. Good correlation coefficients were found for data acquired several days after treatment (ISI, r = 0.749; PEI, r = 0.778). However, they were higher when the post-treatment time interval was 7 days or more (ISI, r = 0.962; PEI, r = 0.934). These results suggest that a post-treatment delay of 7 days is necessary for the accurate assessment of the presence of residual tumour by DCE-MRI parameters.
Département de Radiologie, Hôpital Saint-Luc du CHUM, 1058 St-Denis, Montreal, Quebec, H2X 3J4 Canada.
A
A
Khiat
D
D
Gianfelice
M
M
Amara
Y
Y
Boulanger
D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013997:Time Factors; D014464:Ultrasonic Therapy / Q000379:methods*; D016217:Ultrasonography, Mammary