Comparison of outcomes of free-hand 2-dimensional ultrasound-guided versus navigated 3-dimensional ultrasound-guided biopsy for supratentorial tumours: a single-institution experience with 125 cases

PURPOSE: The purpose of this study was to evaluate the relative utility and benefits of free-hand 2-dimensional intraoperative ultrasound (FUS) and navigated 3-dimensional intraoperative ultrasound (NUS) as ultrasound-guided biopsy (USGB) techniques for supratentorial lesions. METHODS: All patients who underwent USGB for suspected supratentorial tumours from January 2008 to December 2017 were retrospectively analyzed. The charts and electronic medical records of these patients were studied. Demographic, surgical, and pathological variables were collected and analyzed. The study group consisted of patients who underwent either FUS or NUS for biopsy. RESULTS: A total of 125 patients (112 adults and 13 children) underwent USGB during the study period (89 FUS and 36 NUS). NUS was used more often for deep-seated lesions (58% vs. 18% for FUS, P<0.001). The mean operating time for NUS was longer than for FUS (156 minutes vs. 124 minutes, P=0.001). Representative yield was found in 97.7% of biopsies using FUS and in 100% of biopsies using NUS (diagnostic yield, 93.6% and 91.3%, respectively). The majority of lesions (89%) were high-grade gliomas or lymphomas. Postoperative complications were more common in the NUS group (8.3% vs. 1.2%), but were related to the tumour location (deep). CONCLUSION: Despite the longer operating time and higher rate of postoperative complications, NUS has the benefit of being suitable for biopsies of deep-seated supratentorial lesions, while FUS remains valuable for superficial lesions.

Non-enhancing gliomas: does intraoperative ultrasonography improve resections?

PURPOSE: Non-enhancing diffuse gliomas are a challenging surgical proposition. Delineation of tumor extent on preoperative imaging and intraoperative visualization are often difficult. METHODS: We retrospectively analyzed all cases of non-enhancing gliomas that were operated on using navigated 3-dimensional ultrasonography (US). tumor delineation (good, moderate, or poor) on preoperative magnetic resonance imaging (MRI) and intraoperative US was compared. Post-resection US findings with respect to residual tumor status were compared to the postoperative imaging findings. The extent of resection was calculated and recorded. RESULTS: There were 55 gliomas (43 high-grade, 12 low-grade). Forty were close to eloquent areas. The pre-resection concordance of MRI with US was 56%, with US defining more tumors as well-delineated (n=26) than MRI (n=13). US was used for resection control in 50 cases. Gross tumor resection was achieved in 24 cases (51%). US correctly predicted the residual tumor status in 78% of cases. The use of US led to radical resections even in some tumors preoperatively deemed to be unresectable. However, eloquent location was the only independent predictor of the extent of resection. CONCLUSION: Intraoperative US is a useful tool for guiding resection of non-enhancing gliomas. It may be better than MRI for delineating these tumors, and may thereby facilitate improved resection of these otherwise poorly delineated tumors. However, functional boundaries remain the main limiting factor for achieving complete resection of non-enhancing gliomas.