CLINICAL ARTICLE - NEUROSURGICAL TECHNIQUES A practical grading system of ultrasonographic visibility for intracerebral lesions Richard Mair & James Heald & Ion Poeata & Marcel Ivanov Received: 8 May 2013 /Accepted: 31 August 2013 /Published online: 13 September 2013 # Springer-Verlag Wien 2013 Abstract Background Intraoperative ultrasound for intracranial neuro- surgery was largely abandoned in the 1980s due to poor image resolution. Despite many technological advances in ultra- sound since then, the use of this imaging modality in contem- porary practice remains limited. Our aim was to evaluate the utility of modern intraoperative ultrasound in the resection of a wide variety of intracranial pathologies. Methods A total of 105 patients who underwent intracranial lesion resection in a contiguous fashion were prospectively included in the study. Ultrasound images acquired intraoper- atively were used to stratify lesions into one of four grades (grades 0–3) on the basis of their ultrasonic echogenicity and border visibility. Results Forty-two out of 105 lesions (40 %) were clearly identifiable and had a clear border with normal tissue (grade 3). Fifty-five of 105 lesions (52 %) were clearly identifiable but had no clear border with normal tissue (grade 2). Eight of 105 lesions (8 %) were difficult to identify and had no clear border with normal tissue (grade 1). None (0 %) of the lesions could not be identified (grade 0). High-grade gliomas, cerebral metastases, meningiomas, ependymomas, and haemangioblastomas all dem- onstrated a median ultrasonic visibility grade of 2 or greater. Low-grade astrocytomas and oligodendrogliomas demonstrated a median ultrasonic visibility grade of 2 or less. Conclusion Intraoperative ultrasound can be of tremendous benefit in allowing the surgeon to appraise the location, extent, and local environment of their target lesion, as well as to reduce the risk of preventable complications. We believe that our grading system will provide a useful adjunct to the neu- rosurgeon when deciding for which lesions intraoperative ultrasound would be useful. Keywords Intraoperative imaging . Intraoperative ultrasound . Ultrasonography . Brain tumour imaging Introduction One of the important goals for a neurosurgeon is to remove the target lesion without causing neurological deficit. There are many ways in which a surgeon is able to maximise their capacity to achieve this outcome. The ability to localise the tumour with a good degree of accuracy, to estimate the volume of tumour resected, and the proximity of any remnants to normal brain anatomy are all important factors in achieving the primary goal. With this in mind, several methods of intraoperative imaging have been developed to facilitate safe and efficacious tumour removal. Intraoperative ultrasound, neuronavigation, intraoperative MRI and, in high-grade glio- mas, fluorescene-guided techniques (using 5-Aminolevulinic acid (5-ALA)) have all been shown to support safe, more extensive tumour resection [8, 10, 12, 16]. Ultrasound was developed for medical purposes by the American Navy in the 1940s but was first used cranially in the 1950s [1]. It utilises sound waves at frequencies above the human auditory threshold to image planes of tissue in two dimensions. Its use intraoperatively in cranial cases was largely abandoned during the 1980s due to the poor resolution obtained at that time. The technology has advanced significantly since then and users are now able to integrate preoperative MRI/CT *This study has not been presented at a conference R. Mair : J. Heald : M. Ivanov (*) Department of Neurosurgery, Royal Hallamshire Hospital, Glossop Road, Sheffield, UK S102JF e-mail: marcelivanov@gmail.com I. Poeata Department of Neurosurgery, Hospital Nicolae Oblu, University of Medicine and Pharmacy Gr. T. Popa, 2 Ateneului, 700309 Iasi, Romania Acta Neurochir (2013) 155:2293–2298 DOI 10.1007/s00701-013-1868-9