Intraoperative Sonography Opens New Doors for Patient Care

Abstract

Intraoperative ultrasonography (IOUS) has seen a significant increase in usage because of technologic advancements made to transducers and sonographic machines. These advancements have improved the image quality, allowing for better visualization of organs and pathology. The result of better visualization, combined with realtime imaging, has opened the door to numerous applications of sonography in the operating room that were not possible with previous sonographic systems. The continued improvements in speed of data collection and miniaturization will undoubtedly lead to even more widespread applications. 1 IOUS is being used for procedures such as pancreatic imaging for bile duct obstruction and tumor localization, vascular procedures including endarterectomy and a variety of endovascular interventions, laparoscopy procedures, guidance for intraoperative biopsies, guidance for shunt placements, spinal lesion removal, and resection of brain cancers. The focus of this article is on the applications of IOUS in neurosurgery, specifically surgery of the brain.Even with the expanding capabilities of IOUS for the guidance in neurosurgery, the technique still is not used to its full potential. One of the reasons for this is that neurosurgeons are more comfortable interpreting magnetic resonance imaging (MRI) and computed tomography (CT) images compared with sonographic imaging. However, considering that intraoperative MRI and CT are not available in all facilities due to costs and other physical constraints, neurosurgeons are likely to become more open to the possibilities that IOUS holds in the resection of brain tumors. These patients often have a very poor or limited prognosis, and the potential exists to provide the patient with an enhanced likelihood of improving their quality of life postoperatively. HistoryIOUS has been applied since the first sonographic machines were in use. Although IOUS began to be developed in earnest after the development of gray-scale B-mode ultrasonography, and especially after the development of real-time imaging, early investigators were using more primitive tools as early as the 1960s. 1 One of the very first reports of IOUS was by Schlegel et al 2 in 1961, who used A-mode ultrasonography for the localization of renal calculi (Figure 1).Additional early A-mode applications included the detection of stones in the bile duct and in the gallbladder. AbstractIntraoperative ultrasonography (IOUS) is rapidly changing as advancements in technology provide surgeons with more options for the treatment of their patients. Despite the introduction of intraoperative magnetic resonance imaging (MRI) and computed tomography (CT), advancements in IOUS technology and its low cost have kept this a viable modality. The improved image resolution that is available provides neurosurgeons, for example, with the information necessary to adequately resect cancer in the brain, including superficial and deep-set tumors, whether they are primary brain cancers or brain metastases. Strain sonography and contrast-en...