The post-surgical liver: is application of treatment response assessment within the CEUS LI-RADS framework possible?

BACKGROUND AND PURPOSE

To appraise the inclusion of CEUS resection site evaluation in LI-RADS CEUS Nonradiation Treatment Response Assessment (TRA) v2024, currently applied for ablative therapy. We highlight the specific benefits afforded by CEUS in this effort.

METHODS

Retrospective chart review was performed for 102 patients following surgical resection of HCC and ICC with post-operative CEUS at our center. Demographic data, surgical history, CT/MR findings, and resection site appearances on greyscale and CEUS were documented. The resection site where the tumor was originally positioned was designated as the treatment site and the resection margin as the perilesional tissue to establish equal assessment to TRA for ablative therapy. The morphology of the resection site was assigned one of three appearances, using novel descriptors: EDGE, VOID, or SURFACE DIVOT. Resection sites were evaluated for benign appearances, post-surgical changes, and tumor recurrence, and then categorized with a CEUS LI-RADS TRA score.

RESULTS

102 patients had 120 resection sites following 115 operations for 94 HCC and 8 ICC. On CEUS, 59 (49%) were characterized as EDGE, 46 (38%) as VOID, and 15 (13%) as SURFACE DIVOT, n = 120. 23 (19%) of resection sites were LR-TR VIABLE for recurrence, 91 (76%) LR-TR NONVIABLE, and 6 (5%) EQUIVOCAL, n = 120. Benign post-surgical changes developed in 23 (19%) resection sites, n = 120. 63/115 surgeries (55%) had post-operative recurrence, 40 De Novo, 17 Perilesional, and 6 Intralesional.

CONCLUSION

Our conclusions are in two categories: the first assessing the success of CEUS in the assessment of post-surgical treatment sites following liver resections. CEUS can successfully distinguish between unique post-operative appearances such as benign tissue migration, resection VOIDs resembling an intrinsic mass, and true recurrence. CEUS is thus strongly recommended for secondary surveillance following HCC and ICC resection. The second conclusion evaluates the inclusion of resection sites into the CEUS LI-RADS TRA algorithm for ablative therapies. In this regard, we believe that our study was highly successful, improving the perspective of all our staff as to what is important in the assessment of the post-surgical liver on CEUS and the method whereby this information is communicated to our referring clinicians.