title: Colorectal liver metastasis after 90Y radioembolization therapy: pilot study of change in MDCT attenuation as a surrogate marker for future FDG PET response.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether changes in attenuation and size of liver metastatic lesions of colorectal cancer at MDCT 1 month after (90)Y radioembolization treatment are predictive of response at FDG PET 3 months after treatment.
  
  
  METHODS
  Twenty patients with colorectal liver metastasis consecutively treated with (90)Y radioembolization underwent triphasic MDCT of the liver at baseline and 1 and 3 months after treatment and FDG PET at baseline and 3 months after treatment. Percentage change in tumor attenuation at MDCT (volumetric attenuation), tumor size at MDCT (according to Response Evaluation Criteria in Solid Tumors [RECIST] and World health Organization [WHO] criteria), and volume-weighted maximum standardized uptake value at FDG PET were evaluated. The correlation between FDG PET response 3 months after treatment and response according to RECIST, WHO criteria, and attenuation 1 month after treatment was evaluated.
  
  
  RESULTS
  Only 13.3% of patients with FDG PET findings of response 3 months after treatment were identified according to RECIST and WHO criteria 1 month after treatment. According to attenuation criteria at 1 month, however, 53.3% of patients with an FDG PET response at 3 months were identified. A strong association was found between FDG PET response at 3 months and response based on attenuation criteria (odds ratio, 12.4; 95% CI, 0.58-265.3; p = 0.05).
  
  
  CONCLUSIONS
  Early changes in the attenuation of liver metastatic lesions of colon cancer after (90)Y radioembolization treatment may be predictive of future response at FDG PET.
authors.affiliation: Department of Radiology, Northwestern Memorial Hospital, Northwestern University-Feinberg School of Medicine, Chicago, IL 60611, USA.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Tochetto
authors.forename: Hüseyin Gürkan
authors.initials: HG
authors.lastname: Töre
authors.forename: Hamid
authors.initials: H
authors.lastname: Chalian
authors.forename: Vahid
authors.initials: V
authors.lastname: Yaghmai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007472:Iohexol; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy / Q000556:secondary; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D015021:Yttrium Radioisotopes / Q000627:therapeutic use
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes; D019788:Fluorodeoxyglucose F18; D007472:Iohexol