Robert E Maxwell

OBJECTIVE: Lesions within the brain are commonly sampled using stereotactic techniques. The advent of interventional magnetic resonance imaging (MRI) now allows neurosurgeons to interactively investigate specific regions, with exquisite observational detail. We evaluated the safety and efficacy of this new surgical approach.

METHODS: Between January 1997 and June 1998, 35 brain biopsies were performed in a high-field strength interventional MRI unit. All biopsies were performed using ...

OBJECTIVE: Interventional magnetic resonance imaging (MRI) allows neurosurgeons to interactively perform surgery using MRI guidance. High-field strength (1.5-T) imaging permits exceptional observation of intracranial and spinal pathological features. The development of this technology and its application to a variety of neurosurgical procedures are described.

METHODS: We report on the first 101 cases that were treated in the interventional MRI unit (between January 1997 and September ...

With computed tomography (CT) and magnetic resonance imaging stereotactic systems, biopsies of intracranial lesions can be made with safety and ease. Before the development of this technique, neurosurgeons often performed freehand brain biopsies under CT guidance. While stereotactic biopsy is the procedure of choice for small, deep lesions, few studies have compared the morbidity, mortality, and efficacy in obtaining a diagnosis associated with these two techniques for superficial ...

Twenty-four patients (16 men, 8 women) underwent corpus callosum section specifically for improvement of control of atonic or tonic seizures that resulted in falls and injuries. All patients suffered from multiple seizure types, including complex partial (CP) and tonic-clonic (TC) seizures, in addition to the tonic or atonic episodes. Preoperative seizure frequency was quantified for all types for 1 year immediately before surgery and for the most recent year since the procedure; average ...

The aim of this paper was to evaluate the outcome and the factors predictive for a good prognosis of resective surgery for intractable partial epilepsy guided by subdural electrode arrays (SEA's) and operative electrocorticography. Sixty-four patients, aged 8-52 years, were evaluated with chronic SEAs in order to record interictal and ictal activity and delineate speech and motor areas by functionally mapping. Resection were individualized to each patient's SEA recorded ...

All image-guided neurosurgical systems that we are aware of assume that the head and its contents behave as a rigid body. It is important to measure intraoperative brain deformation (brain shift) to provide some indication of the application accuracy of image-guided surgical systems, and also to provide data to develop and validate nonrigid registration algorithms to correct for such deformation. We are collecting data from patients undergoing neurosurgery in a high-field (1.5 T) ...

BACKGROUND: Interventional magnetic resonance (MR) imaging allows neurosurgeons to interactively perform surgery using MR guidance. High-field (1.5-Tesla) strength imaging provides exceptional visualization of intracranial and spinal pathology. The full capabilities of this technology for pediatric neurosurgery have not been defined or determined.

MATERIALS AND METHODS: From January 1997 through June 1998, 10 of 85 cases performed in the interventional MR unit were in the pediatric ...

We studied 95 patients who underwent standard anterior temporal lobectomy (ATL) without stimulation mapping of language areas, using neuropsychological parameters of language function preoperatively and 1 year postoperatively [Boston Naming Test and Verbal Fluency, and the Information, Comprehension, Arithmetic, Similarities, Digit Span, and Vocabulary subtests of the Wechsler Adult Intelligence Scale (WAIS)]. Verbal IQ (VIQ), Performance IQ (PIQ), Full-Scale IQ (FSIQ), and Verbal ...

To determine the frequency that high-field magnetic resonance (MR) imaging sequences influenced surgical decision making during intraoperative MR-guided surgery. From January 1997 to February 2001, 346 MR-guided procedures were performed using a 1.5-Tesla MR system (NT-ACS, Philips Medical Systems). This system can perform functional MR imaging (fMRI), diffusion weighted imaging (DWI), MR spectroscopy (MRS), MR angiography (MRA), and MR venography (MRV) in addition to T1-weighted, ...

PURPOSE: To investigate the challenges and benefits of magnetic resonance (MR) imaging during brain tumor resection.

MATERIALS AND METHODS: A short-bore 1.5-T MR system equipped with echo-planar-capable gradients was used in resection of brain tumors in 30 patients. MR sequences and need for contrast material enhancement were determined on the basis of the targeted lesion. MR images were acquired before, during, and after surgery. Tissue obtained at biopsy or excised as a result of ...

BACKGROUND: Acute hemorrhagic leukoencephalitis (AHLE) is a rare, fatal, central nervous demyelinating disease characterized by a rapid fulminant clinical course. Successful management requires early diagnosis, aggressive management of cerebral edema, and immunosuppression. Therapeutic plasma exchange (TPE) is infrequently used and commences after initial management fails.

CASE REPORT: A 31-year-old man presented with right arm weakness, whose symptoms rapidly progressed to hemiplegia ...

OBJECTIVE: The resection of intramedullary spinal cord lesions (ISCLs) can be complicated by neurological deficits. Neuromonitoring has been used to reduce intraoperative risk. We have used somatosensory evoked potentials (SEPs) and muscle-derived transcranial electrical motor evoked potentials (myogenic TCE-MEPs) to monitor ISCL removal. We report our retrospective experience with the addition of free-running electromyography (EMG).

METHODS: Thirteen patients underwent 14 monitored ISCL ...

OBJECT: The authors describe their initial results obtained using a skull-mounted trajectory guide for intraoperative magnetic resonance (MR) imaging-guided brain biopsy sampling. The device was used in conjunction with a new methodology known as prospective stereotaxis for surgical trajectory alignment.

METHODS: Between January 1999 and March 2000, 38 patients underwent 40 brain biopsy procedures in which prospective stereotaxis was performed with the trajectory guide in a short-bore ...

Direct cortical recordings were taken from 12 patients with implanted subdural electrode arrays during performance of a 2-dimensional, multi-joint, visually guided arm movement task. Task-related changes in the amplitude of the motor cortex 8-12 Hz surface local field oscillations were evaluated for the encoding of direction and amplitude of movement in the 6 patients in whom no epileptogenic or ECoG background abnormalities were detected over the motor-sensory cortical areas under the ...