title: Contrast-enhanced MRI of the breast after limited surgery and radiation therapy.
abstract: OBJECTIVE
  Posttherapeutic changes in the breast after tumorectomy (TE) and radiation therapy (RT) may mimic or obscure recurrent or new malignancies and thus interfere with conventional diagnostic studies. We investigated the enhancement of tissue during variable time intervals after therapy with contrast-enhanced MRI in 62 patients.
  
  
  METHODS
  We report the results of 77 studies in 62 patients undergoing TE and RT. We include only those studies with at least 24 months of clinical and mammographic follow-up (n = 60) or histopathologic results (n = 17).
  
  
  RESULTS
  Up to 9 months after therapy, differentiation between posttherapeutic changes and recurrence was frequently impossible because of the strong enhancement. Ten to 18 months after therapy, this posttherapeutic enhancement subsided slowly with some interindividual variations. After 18 months posttherapy, no significant enhancement was encountered in 30 of 32 cases. Diffuse or focal enhancement was present in all recurrent tumors and all recurrences were correctly diagnosed. Furthermore, 4 of 11 recurrences and 10 of 18 single recurrent foci were detected by MR alone, based on focal enhancement.
  
  
  CONCLUSIONS
  Accordingly, contrast-enhanced MR is not recommended during the first 9 months after therapy. Nine to 18 months after therapy, it may be helpful in those two-thirds of cases where the scar does not enhance. If enhancement takes place (one-third of cases), it may represent either scar or tumor, and in such circumstances, enhanced MR is of no value. After 18 months, enhanced MRI has proven a valuable additional tool. By correctly detecting or excluding recurrent tumor, it can significantly improve diagnostic accuracy.
authors.affiliation: Department of Radiology, University of Leipzig, Germany.
authors.forename: S H
authors.initials: SH
authors.lastname: Heywang-Köbrunner
authors.forename: A
authors.initials: A
authors.lastname: Schlegel
authors.forename: R
authors.initials: R
authors.lastname: Beck
authors.forename: T
authors.initials: T
authors.lastname: Wendt
authors.forename: W
authors.initials: W
authors.lastname: Kellner
authors.forename: B
authors.initials: B
authors.lastname: Lommatzsch
authors.forename: M
authors.initials: M
authors.lastname: Untch
authors.forename: W B
authors.initials: WB
authors.lastname: Nathrath
mesh_terms: D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy / Q000601:surgery; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D015412:Mastectomy, Segmental; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA