Factors determining the sensitivity of intraoperative ultrasonography in detecting colorectal liver metastases in the modern era.
BACKGROUND
With improved preoperative cross-sectional imaging, the added clinical value of intraoperative ultrasonography (IOUS) in the detection of colorectal liver metastases (CRLM) is unclear. Specifically, the ability of IOUS to detect additional liver metastases during surgery and its relationship between clinical and lesion specific ultrasonographic characteristics remains ill-defined. The purpose of the current study was to determine the association of clinical parameters and tumor echogenicity with the ability of IOUS to detect occult CRLM.


METHODS
A total of 213 patients undergoing surgical exploration and IOUS for CRLM between 1998 and 2009 were included in the study. All patients underwent preoperative multidetector computed tomography (CT) imaging and lesion detection was compared with those identified by IOUS. In addition, early (<6 months) intrahepatic recurrence was used as a surrogate for residual disease (e.g., metastases that were undetected on initial IOUS). The influence of various characteristics on the rate in which additional metastases were detected and the rate of early intrahepatic recurrence was examined.


RESULTS
Overall, IOUS detected additional liver metastases in 10% of patients (n = 22). Detection of additional metastases was significantly higher in patients with multiple (≥4) tumors (P < 0.001) and hypoechoic tumors (P = 0.007). Of 153 patients undergoing resection only, 17 (11%) had an early intrahepatic recurrence. This was more common in patients with isoechoic metastases during IOUS (P = 0.03).


CONCLUSIONS
Even with the use of modern cross-sectional preoperative imaging, IOUS detects additional liver metastases in 10% of patients. In addition, the sensitivity of IOUS for detecting occult CRLM is highly dependent on the number and echogenicity of detected tumors.
Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Mark G
MG
van Vledder
Timothy M
TM
Pawlik
Sanjay
S
Munireddy
Ulrike
U
Hamper
Mechteld C
MC
de Jong
Michael A
MA
Choti
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007430:Intraoperative Care; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D009367:Neoplasm Staging; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional; D055815:Young Adult