title: Real-time ultrasonography-computed tomography fusion imaging for staging of hepatic metastatic involvement in patients with colorectal cancer: initial results from comparison to US seeing separate CT images and to multidetector-row CT alone.
abstract: OBJECTIVE
  To prospectively evaluate the role of real-time ultrasonography (US)-computed tomography (CT) fusion imaging (US-CT) in comparison with US seeing separate CT images (US + CT) and multidetector-row CT (MDCT) for the correct staging of hepatic metastatic involvement in patients with colorectal cancer.
  
  
  METHODS
  Sixty-four patients with newly diagnosed colorectal cancer and who were referred for abdominopelvic staging before primary tumor resection underwent same-day MDCT, US + CT, and US-CT. Examinations were evaluated on-site by 2 investigators in consensus. Investigators recorded the size and location of detected lesions on segmental liver maps, classified them as being benign, malignant, or indeterminate, and finally assessed the M stage of the liver as being M0, M1, or Mx (indeterminate). All patients underwent surgical exploration including intraoperative US. Reference standard diagnosis was based on findings at surgery, intraoperative US, histopathology, and MDCT follow-up imaging. Differences among investigated modalities were analyzed using McNemar's test.
  
  
  RESULTS
  The reference standard verified 109 (45 < or = 1 cm) hepatic lesions in 25 patients, including 65 (25 < or = 1 cm) metastases in 16 patients (M1). Regarding the 45 < or = 1 cm liver lesions, rates for detection were significantly higher (P < 0.05) for MDCT (80%, 36/45) and US-CT (77.8%, 35/45) than for US + CT (64.4%, 29/45); the rate for correct classification by US-CT (71.1%, 32/45) was significantly higher than for US + CT (48.9%, 22/45) and MDCT (31.1%, 14/45) (all P < 0.05). On patient-based analysis, specificity of MDCT (85.4%, 41/48) was significantly lower (P < 0.05) than for US-CT (97.9%, 47/48) and US + CT (93.7%, 45/48); the positive predictive value of MDCT (63.1%, 12/19) was not significantly different (P = 0.27) compared with US + CT (82.3%, 14/17) but significantly lower (P < 0.05) than for US-CT (93.7%, 15/16). In 13 patients (59 lesions) with only benign (stage M0) or coexistent benign and malignant lesions (stage M1), indeterminate lesion ratings and indeterminate liver stagings (Mx) occurred both significantly lower (P < 0.05) with US-CT (3.4%, 2/59; and 0%, 0/13) than with US + CT (11.9%, 7/59; and 23.1%, 3/13) or with MDCT (30.5%, 18/59; and 53.8%, 7/13).
  
  
  CONCLUSIONS
  Based on these initial diagnostic experiences, complementary US-CT fusion imaging of small CT-indeterminate liver lesions may have value in staging patients with colorectal cancer, focusing on patients who were likely to harbor only benign or coexisting benign and malignant liver lesions and in whom change of M staging would change the clinical management.
authors.affiliation: Department of Oncology, Asklepios Hospital Altona, Hamburg, Germany. a.stang@asklepios.com
authors.forename: Axel
authors.initials: A
authors.lastname: Stang
authors.forename: Handan
authors.initials: H
authors.lastname: Keles
authors.forename: Suna
authors.initials: S
authors.lastname: Hentschke
authors.forename: Cay
authors.initials: C
authors.lastname: Seydewitz
authors.forename: Martin
authors.initials: M
authors.lastname: Keuchel
authors.forename: Christopher
authors.initials: C
authors.lastname: Pohland
authors.forename: Joachim
authors.initials: J
authors.lastname: Dahlke
authors.forename: Hauke
authors.initials: H
authors.lastname: Weilert
authors.forename: Johannes
authors.initials: J
authors.lastname: Wessling
authors.forename: Ernst
authors.initials: E
authors.lastname: Malzfeldt
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D003199:Computer Systems; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000556:secondary / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D036542:Tomography, Spiral Computed / Q000295:instrumentation / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods