Computed Tomography Imaging Features and Changes in Hemostatic Agents After Laparoscopic Partial Nephrectomy

Urologists and radiologists should be aware of the CT scan appearance of laparoscopic partial nephrectomy (LPN) with the various hemostatic agents since they may confound the interpretation of these radiographic findings. We report the various postoperative CT scan appearance and changes after LPN.

We reviewed CT scans retrospectively (within 3 months) of 86 patients who underwent LPN using various hemostatic agents between March 2008 and July 2014. We analyzed the CT findings after LPN, including postoperative changes, tumor recurrence, and complications. We also discuss changes in abnormal features, such as mass-like lesions and gas formation, on follow-up CT scans.

To categorize the postoperative changes, we classified them according to their specific CT findings: (1) a combination of perinephric stranding and postsurgical fluid collection (n = 46), (2) mass-like lesions (n = 35), (3) a parenchymal defect (n = 2), (4) local recurrence at the surgical site (n = 1), (5) a large hematoma as a complication after LPN (n = 2), (6) gas pockets, which may be a response to postsurgical fluid collection around soft tissue (n = 35), (7) fat at the excision site (n = 2; Fig. 7 ), and (8) contrast extravasation in the delayed phase (n = 1). Mass-like lesions were visible in 35 cases. The average change in size of bolster masses was -1.19 mm/month. However, the overall change in enhancement of mass-like lesions was not significant over time. Foci of gas were noted in 16 patients at the resection site in the first follow-up period (<3 months), as late as 40 days after the procedure.

Knowledge of CT imaging features and changes in hemostatic agents following LPN is important in interpreting postoperative CT scans, as postoperative changes can be confused with tumor recurrence and can mimic abscesses.