Objective:

Intraoperative ultrasound (IOUS) has been increasingly used as a guiding tool during neurosurgical procedures. In this study

we aimed to evaluate the potential application of IOUS-assisted surgery in the resection of small

deepseated

or ill-defined lesions.

Methods:

Eighty-six consecutive patients with small

deep-seated

or ill-defined intracerebral lesions were studied prospectively. An improved intraoperative imaging technique and surgical setup were practiced during the surgery. IOUS was performed in three orthogonal imag

ing planes (horizontal

coronal and sagittal).

Results:

Histopathological diagnoses of these 86 cases included cavernomas

metastases

hemangioblastomas

gliomas

and radiation necrosis. Forty-seven of the 86 lesions (54.7%) were small and deep-seated

34 (39.5%) were ill-defined

and 5 (5.8%) were small

deep-seated

and ill-defined. Sonograms in the horizontal plane were obtained in all 86 cases. Sonograms in the sagittal plane and in the coronal plane were obtained only in 52 cases and in 46 cases

respectively

due to technical limitation. In 13 cases

sonograms in all three orthogonal planes were available. All lesions were successfully identified and localized by IOUS. Total resection was performed in 67 lesions (77.9%) and partial resection was performed in 19 lesions (22.1%).

Conclusion:

We propose IOUS to be performed in three orthogonal planes when surgery is planned for small

deep-seated

or ill-defined brain lesions. By applying this simple

improved technique

surgeons can perform resection of these lesions precisely.