This article chronicles the development of real-time ultrasound for use in operations in the central nervous system. Described are the technology and the various applications of ultrasound in the neurosurgical operating room. The use of real-time ultrasound to localize, characterize, and instrument lesions of the brain and spinal chord are discussed.
"The application of varying adjuvant electronic devices during neurosurgical procedures, such as the intraoperative ultrasound (IOUS) requires extensive training and well anatomic knowledge. Since the widespread introduction of the IOUS into neurosurgery in the 1980s, multiple studies have demonstrated its efficacy in localizing intracranial lesions and resection control among many other applications, especially since frame-based and frameless stereotactic surgery and an intraoperative magnetic resonance imaging (MRI) are not available in most developing countries. Therefore biological in vivo and in vitro models, as well as artificial and virtual reality neurosurgical training tools can provide suitable assistance in various training settings, carrying their own unique advantages and disadvantages. "
[Show abstract][Hide abstract] ABSTRACT: The present study evaluates the effectiveness of an ultrasound (US) practice course based on a sheep brain cadaver. Neurosurgical education is considerably restrained following patient safety objections and work time restrictions. It is therefore of vital importance to offer residents an opportunity to practice certain US techniques in a controlled environment without ethical or legal restrictions. We developed an US training model based on a sheep brain cadaver in order to demonstrate the feasibility of such a model, facilitate crucial anatomic knowledge, and demonstrate a learning curve from it.
Over the course of 2 months from December 2012-January 2013, a total of 13 residents took part in a three part training session, each consisting of 20-30 min of individual US-training and performance evaluation based on a biological phantom. The first cadaver was a physiologic sheep brain. After initial familiarization with the US, the residents performed an US on a second cadaveric brain and tried to find a 0.5 cm big (in diameter) echogenic structure. In a third brain they were asked to identify a cyst (Fogarty catheter filled with water).
Thirteen neurosurgical residents participated in the study. After the first training session, the learning curve improved significantly in the second and the third session. The ability to actuate the US device, the time needed to display crucial anatomic landmarks, and to locate the two different artificial masses increased, and respectively decreased remarkably by up to 80%.
After 2 months and three training sessions, the handling of the US from the residents was excellent in the operating room. The accuracy and the dexterity in use of the US improved significantly. The participants found the model to be realistic and agreed on the need for further promotion of such courses.
Surgical Neurology International 04/2014; 5(1):46. DOI:10.4103/2152-7806.130314 · 1.18 Impact Factor
"In neurosurgery, ultrasound imaging has been employed in many cases of brain examinations over the last two decades . Several studies demonstrated that ultrasonography can be used for locating tumors, defining their margins, differentiating their internal characteristics, and for detecting of brain shift and residual tumoral tissues . At present, 3D US imaging is integrated within the neuronavigation systems to provide a useful and efficient intraoperative tool . "
[Show abstract][Hide abstract] ABSTRACT: The registration of intraoperative ultrasound (US) images with preoperative magnetic resonance (MR) images is a challenging problem due to the difference of
information contained in each image modality. To overcome this difficulty, we
introduce a new probabilistic function based on the matching of cerebral hyperechogenic structures. In brain imaging, these structures are the liquid interfaces such as the cerebral falx and the sulci, and the lesions when the corresponding tissue is hyperechogenic. The registration procedure is achieved by maximizing the joint probability for a voxel to be included in hyperechogenic structures in both modalities. Experiments were carried out on real datasets acquired during neurosurgical procedures. The proposed validation framework is based on (i) visual assessment, (ii) manual expert estimations , and (iii) a robustness study. Results show that the proposed method (i) is visually efficient, (ii) produces no statistically different registration accuracy compared to manual-based expert registration, and (iii) converges robustly. Finally, the computation time required by our method is compatible with intraoperative use.
International Journal of Biomedical Imaging 01/2012; 2012(3):531319. DOI:10.1155/2012/531319
"However, this technology is prohibitively expensive thereby preventing its widespread application in neurosurgical setups the world over. Real time ultrasound was used for intraoperative localization in neurosurgery way back in the late 1970s, much before the MRI was even available for diagnostic purposes. In the intraoperative setting the US has potential use and wider application especially in neuro-oncology. "
[Show abstract][Hide abstract] ABSTRACT: Localization and delineation of extent of lesions is critical for safe maximal resection of brain and spinal cord tumors. Frame-based and frameless stereotaxy and intraoperative MRI are costly and not freely available especially in economically constrained nations. Intraoperative ultrasound has been around for a while but has been relegated to the background. Lack of objective evidence for its usefulness and the perceived "user unfriendliness" of US are probably responsible for this. We recount our experience with this "forgotten" tool and propose an objective assessment score of its utility in an attempt to revive this practice.
Seventy seven intraoperative ultrasound (IOUS) studies were carried out in patients with brain and spinal cord tumors. Seven parameters were identified to measure the "utility" of the IOUS and a "utility score" was devised (minimum 0 and maximum 7). Individual parameter and overall scores were calculated for each case.
IOUS was found to be useful in many ways. The median overall score was 6 (mean score 5.65). There were no scores less than 4 with the majority demonstrating usefulness in 5 or more parameters (91%). The use of the IOUS significantly influenced the performance of the surgery in these cases without significantly prolonging surgery.
The IOUS is a very useful tool in intraoperative localization and delineation of lesions and planning various stages of tumor resection. It is easy, convenient, reliable, widely available, and above all a cost-effective tool. It should be increasingly used by neurosurgeons in the developing world where costlier intraoperative localization and imaging is not available freely.
Journal of Neurosciences in Rural Practice 03/2011; 2(1):4-11. DOI:10.4103/0976-3147.80077
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