Yield and utility of routine postoperative imaging after resection of brain metastases.

Magnetic resonance imaging (MRI) or computerized tomography (CT) is routinely performed after resection of brain metastases (BrM), regardless of whether there are specific clinical concerns about residual tumor or potential complications. Routine imaging studies contribute a significant amount to the cost of medical care, and their yield and utility are unknown. An IRB-approved retrospective chart review study was performed to analyze all craniotomies for BrM performed at our institution from 2005 to 2012. Descriptive statistics were used to quantify the yield of postoperative imaging. 218 consecutive patients underwent 226 craniotomies for BrM. In 21 cases, new or worsened neurologic deficits occurred after surgery (9.0%), and 19 of the 21 underwent postoperative imaging. 9 of the 19 patients (47%) had significant findings on postoperative imaging, and 2 patients required reoperation. 201 patients had no new neurologic deficits (91%), and 23 of these patients had no postoperative imaging. Of the 178 remaining patients, 160 underwent postoperative MRI and 18 underwent postoperative CT. 9 patients (5.1%) had unexpected adverse imaging findings; 6 had small stroke, 1 had a subdural hemorrhage and 2 had possible or definite venous sinus occlusion. None of the imaging findings led to changes in management. 182 patients underwent imaging appropriate to detect residual tumor (177 gadolinium enhanced MRI and 5 contrast enhanced CT). Of these patients, 16 were known to have small residual tumors based on intraoperative findings. Of the remaining 166 patients felt to have had gross total tumor resection, 9 (5.4%) were found to have a small amount of residual tumor on postoperative imaging; no patient had a change in treatment plan as a result. Routine postoperative imaging in patients undergoing craniotomy for BrM has a very low yield and may not be appropriate in the absence of new neurologic deficits, or specific clinical concerns about large amounts of residual tumor or intraoperative complications.