The beneficial potential of ultrasound for neurosurgical procedures has been noted for decades. However, after intraoperative manipulations, many acknowledge that there are difficulties in obtaining high-quality images. Therefore, we analyzed the causes of these problems and possible measures to prevent them. Intraoperative ultrasonography (IOUS) was performed on patients with intracranial mass lesions using a convex-type ultrasound probe (7.5MHz). We performed mainly B-mode scan, and adjusted the imaging parameters when images were of poor quality. We obtained high-quality images with pre-procedural IOUS, but this became more difficult after surgical manipulation. We found that it was very important to position the head to allow filling of the skull with saline by rotation of the operation bed. Walls of cavities left after lesion removal by electrocoagulation and cottonoid coverings were the major causes of poor imaging of residual tumors. This problem was overcome by carrying out IOUS of residual tumors from the intact brain surface, rather than via the removal cavities. Adoption of these strategies made IOUS a very easy and useful intraoperative navigation tool.
