Postop Reactive Enhancement After Resection of Brain Tumors
Postop Reactive Enhancement After Resection of Brain Tumors
We examined a total of 46 patients (33 male; mean age 62.5 years, range 26–79 years) with newly diagnosed malignant gliomas who underwent either gross-total or partial tumor resection.
Histopathological analysis demonstrated glioblastomas in 44 patients, anaplastic astrocytoma (WHO Grade III) in 1 patient, and gliosarcoma in 1 patient.
An intraoperative MRI (iMRI)–guided procedure with "double dose" application of Gd-DTPA (0.2 mmol/kg) was performed in 21 patients. Patients for whom iMRI guidance was used received contrast agent twice per surgery. In 25 patients no iMRI guidance was used.
Postsurgical MR scans were acquired within the first 72 hours after surgery in 41 patients (mean 35:40 hours, range 22:57–56:08 hours) and after 72 hours in 5 patients (mean 86:50 hours, range 73:46–107:33 hours).
On the nonenhanced T1-weighted images, hyperintense areas (methemoglobin) of different degrees and forms were present in the resection site of all patients.
Postoperative reactive enhancement patterns (marginal or leptomeningeal/dural enhancement) were noted in 15 (32.6%) of 46 patients—7 patients in whom iMRI guidance was used and 8 patients in whom it was. In 6 (40%) of these 15 patients additional residual tumor was also present in a portion of the resection cavity distant from the site of the early postoperative reactive enhancement; 1 of these patients had undergone an iMRI-guided procedure.
Reactive enhancement was present within the first 72 hours in 13 (28.3%) of 46 patients (mean 34:30 hours). The earliest occurrence of marginal enhancement was within 22:57 hours after surgery. In 2 patients marginal enhancement occurred beyond 72 hours after surgery (mean 91:27 hours).
Subsequent MR scans in these patients with reactive enhancement on the first postoperative scan after surgery demonstrated no evidence that this enhancement was residual tumor, and no tumor recurrence occurred in these regions.
In our series, 1 of the 3 patients examined within 24 hours following surgery exhibited reactive enhancement not attributable to residual tumor. None of these patients had undergone surgery with iMRI.
Between 24 and 48 hours postoperatively, 6 (35.3%) of 17 iMRI group and 3 (23.1%) of 13 in the non-iMRI group exhibited reactive enhancement.
Beyond 48 hours postoperatively, 1 (25.0%) of 4 patients in the iMRI group and 5 (55.6%) of 9 patients in the non-iMRI group had evidence of reactive enhancement.
Seven of the 13 patients with postoperative reactive enhancement within the 72-hour window had undergone iMRI-guided tumor resection in which Gd was applied intraoperatively. The percentage of patients with postoperative reactive enhancement did not differ between the patients with and without iMRI (33% and 32%, respectively). In the 7 patients who underwent iMRI-guided surgery and who had postoperative reactive enhancement, the MRI had been performed within a mean of 34:12 hours after surgery (range 25:35–53:34 hours). In the 8 patients who did not undergo iMRI-guided surgery, the postsurgical MRI was done within a mean of 49:35 hours (range 22:57–107:33 hours).
Enhancement of residual tumor in areas also evident on the presurgical scans was present in 31 patients (67.4%). None of these patients underwent a second surgery or stereotactic biopsied. Nine of the 31 patients had received a contrast agent intraoperatively for iMRI.
Results
We examined a total of 46 patients (33 male; mean age 62.5 years, range 26–79 years) with newly diagnosed malignant gliomas who underwent either gross-total or partial tumor resection.
Histopathological analysis demonstrated glioblastomas in 44 patients, anaplastic astrocytoma (WHO Grade III) in 1 patient, and gliosarcoma in 1 patient.
An intraoperative MRI (iMRI)–guided procedure with "double dose" application of Gd-DTPA (0.2 mmol/kg) was performed in 21 patients. Patients for whom iMRI guidance was used received contrast agent twice per surgery. In 25 patients no iMRI guidance was used.
Postsurgical MR scans were acquired within the first 72 hours after surgery in 41 patients (mean 35:40 hours, range 22:57–56:08 hours) and after 72 hours in 5 patients (mean 86:50 hours, range 73:46–107:33 hours).
On the nonenhanced T1-weighted images, hyperintense areas (methemoglobin) of different degrees and forms were present in the resection site of all patients.
Postoperative Reactive Enhancement
Postoperative reactive enhancement patterns (marginal or leptomeningeal/dural enhancement) were noted in 15 (32.6%) of 46 patients—7 patients in whom iMRI guidance was used and 8 patients in whom it was. In 6 (40%) of these 15 patients additional residual tumor was also present in a portion of the resection cavity distant from the site of the early postoperative reactive enhancement; 1 of these patients had undergone an iMRI-guided procedure.
Reactive enhancement was present within the first 72 hours in 13 (28.3%) of 46 patients (mean 34:30 hours). The earliest occurrence of marginal enhancement was within 22:57 hours after surgery. In 2 patients marginal enhancement occurred beyond 72 hours after surgery (mean 91:27 hours).
Subsequent MR scans in these patients with reactive enhancement on the first postoperative scan after surgery demonstrated no evidence that this enhancement was residual tumor, and no tumor recurrence occurred in these regions.
In our series, 1 of the 3 patients examined within 24 hours following surgery exhibited reactive enhancement not attributable to residual tumor. None of these patients had undergone surgery with iMRI.
Between 24 and 48 hours postoperatively, 6 (35.3%) of 17 iMRI group and 3 (23.1%) of 13 in the non-iMRI group exhibited reactive enhancement.
Beyond 48 hours postoperatively, 1 (25.0%) of 4 patients in the iMRI group and 5 (55.6%) of 9 patients in the non-iMRI group had evidence of reactive enhancement.
iMRI-guided Surgery
Seven of the 13 patients with postoperative reactive enhancement within the 72-hour window had undergone iMRI-guided tumor resection in which Gd was applied intraoperatively. The percentage of patients with postoperative reactive enhancement did not differ between the patients with and without iMRI (33% and 32%, respectively). In the 7 patients who underwent iMRI-guided surgery and who had postoperative reactive enhancement, the MRI had been performed within a mean of 34:12 hours after surgery (range 25:35–53:34 hours). In the 8 patients who did not undergo iMRI-guided surgery, the postsurgical MRI was done within a mean of 49:35 hours (range 22:57–107:33 hours).
Residual Tumor Enhancement
Enhancement of residual tumor in areas also evident on the presurgical scans was present in 31 patients (67.4%). None of these patients underwent a second surgery or stereotactic biopsied. Nine of the 31 patients had received a contrast agent intraoperatively for iMRI.
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