A meta-analysis evaluating contrast-enhanced intraoperative ultrasound (CE-IOUS) in the context of surgery for colorectal liver metastases

Abdom Radiol (NY). 2021 Sep;46(9):4178-4188. doi: 10.1007/s00261-021-03096-7. Epub 2021 May 9.


Background: This study aimed to assess the outcomes of contrast-enhanced intraoperative ultrasound (CE-IOUS) for patients with colorectal liver metastases (CRLMs) undergoing surgery.

Method: A thorough literature search was performed in PubMed, Scopus, and Cochrane databases, in accordance with the PRISMA guidelines. The Odds Ratio, Weighted Mean Difference, and 95% Confidence Interval were evaluated, by means of Random-Effects model.

Results: Eleven articles met the inclusion criteria and incorporated 497 patients. The present study shows that CE-IOUS is associated with higher sensitivity and accuracy compared with multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and intraoperative ultrasound (IOUS) in identifying CRLMs (p < 0.05). The positive predictive value was similar among the different modalities. Furthermore, new CRLMs were identified by CE-IOUS, thus affecting the surgical plan in 128 patients (51.8% of the patients with new CRLMs). Moreover, 91 patients (71%) underwent a more extensive hepatectomy and 15 patients (11.7%) were considered non-operable. Two alternative contrast agents, Sonazoid and Sonovue, were employed with similar sensitivity (p > 0.05).

Conclusion: These outcomes suggest the superiority of the CE-IOUS over MDCT, MRI, and IOUS for the staging of patients with CRLMs undergoing surgery. However, they should be treated with caution given the small number of the included studies.

Keywords: CE-IOUS; CRLM; Colorectal liver metastases; Contrast-enhanced intraoperative ultrasound; Meta-analysis.

Publication types

  • Meta-Analysis

MeSH terms

  • Colorectal Neoplasms* / diagnostic imaging
  • Contrast Media
  • Hepatectomy
  • Humans
  • Intraoperative Care
  • Liver Neoplasms* / diagnostic imaging
  • Liver Neoplasms* / surgery
  • Magnetic Resonance Imaging
  • Ultrasonography


  • Contrast Media