Limited detection of small (≤ 10 mm) colorectal liver metastasis at preoperative CT in patients undergoing liver resection

Abstract

ObjectiveTo retrospectively determine the sensitivity of preoperative CT in the detection of small (≤ 10 mm) colorectal liver metastasis (CRLM) nodules in patients undergoing liver resection.MethodsThe institutional review board approved the study and waived informed consent. We included 461 pathologically confirmed CRLM nodules in 211 patients (including 71 women; mean age, 66.4 years) who underwent 229 liver resections following abdominal CT. Prior to 163 resections, gadoxetic acid-enhanced liver MR imaging was also performed. Nodules were matched between pathology reports and prospective CT reports following a predefined algorithm. Per-nodule sensitivity of CT was calculated by nodule-size category. Generalized estimating equations were used to adjust for within-case correlation.ResultsFourteen nodule sizes were missing in the pathology report. Nodules of 1–5 mm and 6–10 mm accounted for 8.1% (n = 36) and 23.5% (n = 105) of the remaining 447 nodules, and the number of nodules gradually decreased as nodule size increased beyond 10 mm. The overall sensitivity of CT was 81.2% (95% confidence interval, 77.1%, 85.2%; 365/461). The sensitivity was 8% (0%, 17%; 3/36), 55% (45%, 65%; 59/105), 91%, 95%, and 100% for nodules of 1–5 mm, 6–10 mm, 11–15 mm, 16–20 mm, and >20 mm, respectively. The nodule-size distribution was similar between resections undergoing gadoxetic acid-enhanced MR imaging and those not undergoing the MR imaging.ConclusionCT has limited sensitivity for nodules of ≤ 10 mm and particularly of ≤ 5 mm.

Management of indeterminate hepatic nodules and evaluation of factors predicting their malignant potential in patients with colorectal cancer

“…For both open and laparoscopic surgery, the surgeons mobilized and evaluated the liver by inspection and/or palpation. In addition the surgeons or radiologists who had full knowledge of the preoperative imaging findings performed intraoperative liver ultrasonography (SSD-3500, Aloka, Japan; MylLab 25 Gold, Esaote Biomedica, Italy; or iU22, Philips Medical Systems, The Netherlands) to detect new lesions and further characterization of small indeterminate nodules 13 . Any metastatic nodules identified on intraoperative liver ultrasound (IOUS) were either resected or ablated.…”

Imaging evaluation of the liver in oncology patients: A comparison of techniques

“…Therefore, it is crucial to ensure the best imaging method to detect them, mainly the smaller ones, which can be easily missed. Ko et al [ 50 ] showed that the sensitivity of CT was 8%, 55%, 91%, and 100% for nodules of 1-5 mm, 6-10 mm, 11-15 mm, and > 20 mm, respectively. Consequently, it appears obvious that in metastases that are "too small to characterize," CT has a limited role, particularly for those smaller than 5 mm[ 50 ].…”

Multimodality Approach in Detection and Characterization of Hepatic Metastases

“…Further studies are required to establish the role of alternative imaging modalities, for example, gadoxetic acid-enhanced MRI in improving sensitivity in the detection of subcenter meter hepatic metastases particularly in patients with suspected colorectal liver metastases. 40…”