Navigated intraoperative ultrasonography for brain tumors: a pictorial essay on the technique, its utility, and its benefits in neuro-oncology

Intraoperative imaging has become one of the most important adjuncts in neurosurgery, especially in the surgical treatment of intra-axial tumors. Navigation and intraoperative magnetic resonance imaging have limitations, and intraoperative ultrasonography (IOUS) has emerged as a versatile and multifaceted alternative. With technological advances in ultrasound scanners and newer multifunctional probes, the potential of IOUS is increasingly being utilized in the resection of tumors. The addition of image guidance to IOUS has exponentially increased the power of this technique. Navigated ultrasonography (nUS) can now overcome many of the limitations of conventional standalone two-dimensional ultrasonography. In this pictorial essay, we outline our nUS technique (both two- and three-dimensional) for the resection of intra-axial tumors with illustrated examples highlighting the various steps and corresponding benefits of the technique.

Independent origin of anterior interventricular and left marginal arteries from the left posterior aortic sinus / 대한해부학회지

We present a unique, unreported variation of the left coronary artery. During dissection classes for first-year medical students, we observed the absence of left coronary artery in an adult male cadaver aged approximately 78 years. The left aortic sinus was dilated and it gave origin to anterior interventricular and left marginal arteries independently. Left marginal artery was large and the circumflex artery arose from it. There were two independent opening for anterior interventricular and left marginal arteries in the left posterior aortic sinus. No variations were found in the origin and branching pattern of right coronary artery and the walls and chambers of the heart.

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.