Faculty Bibliography

OBJECT: Resection of lesions involving the supplementary motor area (SMA) may result in immediate postoperative motor and speech deficits that are reversible in most cases. In the present study the authors aimed to determine the critical involvement of SMA in the lesioned and healthy hemispheres in this functional recovery. They hypothesized that compensatory mechanisms take place following surgery in the SMA, and that these mechanisms can involve either the lesioned or the non-lesioned hemisphere. In addition, they hypothesized that a correlation will be present between the functional MR imaging (fMR) imaging-related activation in the SMA and the occurrence of a functional deficit during intraoperative cortical stimulation. METHODS: Twenty-six patients scheduled for resection of space-occupying lesions involving, or in the vicinity of, the SMA were recruited. Patients underwent an fMR imaging examination that included finger-tapping and verb-generation tests to assess for motor and language functions. Intraoperatively direct cortical stimulation (DCS) of the SMA region was performed while patients were monitored for language and motor functions using tests similar to those used for the fMR imaging. Task dysfunction during DCS assessed the critical involvement of the SMA in the tested functions. Neurological evaluations were performed prior to surgery and at 3 time points within a month following surgery. A region of interest-based approach was used to evaluate fMR imaging blood oxygen level-dependent activation level and asymmetry in the SMA. These measurements were later compared with the intraoperative DCS and neurological findings. RESULTS: Functional MR imaging showed greater activation and dominance of the SMA in the lesioned hemisphere in patients who exhibited no motor or language dysfunction during DCS. In addition, patients with the highest activation of the SMA in the lesioned hemisphere for language and motor tests showed stronger coupling of this region with ipsilateral motor and language networks. In contrast, activation in the nonlesioned hemisphere did not correspond with DCS results. CONCLUSIONS: The authors' findings demonstrate the necessity of activation in the vicinity of the lesioned SMA for functional compensation in motor and language tasks. It is possible that more effective functional coupling of the SMA with motor and language areas in the same hemisphere prevents dysfunctions following surgical intervention. Importantly, fMR imaging activation in the unaffected SMA was not sufficient for development of functional compensation and, if anything, indicated decompensation.

Glioblastoma multiforme, a neoplasm with variable histological and biological features, is characterized by diverse imaging features, including highly heterogeneous enhancement. This reflects variable disruption of the blood brain barrier and inherent differences in the vascularity of the tumor. Experience in treating malignant glioma with antiangiogenic drugs is growing, and the most commonly used, in combination with irinotecan or other cytotoxic agents as salvage therapy, is bevacizumab, a monoclonal antibody against vascular endothelial growth factor.A 42-year-old, right-handed person with recurrent glioblastoma multiforme presented with two synchronous foci of recurrent disease in follow-up: one area with enhancement and another one nonenhancing and infiltrative, which responded differently to treatment with bevacizumab and irinotecan. Our example demonstrates the heterogeneous nature of glioblastoma multiforme and is proof of principle for antiangiogenic treatment in selected enhancing, presumably angiogenic forms of glioblastoma multiforme. Antiangiogenic treatment may be ineffective in more infiltrative, biologically different lesions.

Amyloidoma is a term referring to a tumor-like deposition of extracellular insoluble fibrillar protein. Tumor-like amyloid formation in the brain had been described in isolated cases. However no advanced radiological studies to characterize these lesions have been reported. In the report, we have describe a 59-year-old woman, presented several months prior to diagnosis with memory decline, dizziness, walking instability, and speech difficulties. MRI revealed a left basal ganglia lesion with an intraventricular component. The patient underwent a stereotactic biopsy, which confirmed the diagnosis of amyloidoma, an extensive radiographic characterization of amyloidoma using advanced MR techniques was done, including magnetic resonance spectroscopy, dynamic susceptibility contrast, susceptibility weighted image (SWI), and magnetization transfer (MTR). All advanced MR techniques were able to characterize the amyloidoma as a non-neoplastic process. This is an example where such methods can be used for differential diagnosis of atypical brain lesions.

OBJECT: Orbital tumors can be divided schematically into primary lesions, originating from the orbit itself, and secondary lesions, extending to the orbit from neighboring structures. These tumors are variable in their biological nature and in their location. The authors evaluate 41 cases of benign and malignant tumors involving the orbit and discuss the surgical challenge, which involves tumor removal, preserving visual function and cosmetic reconstruction. METHODS: The authors performed a retrospective analysis of a series of all cases involving patients who underwent surgery for treatment of orbital tumors in their hospital between December 2003 and December 2006. Data were collected from the patients' files in the hospital's outpatient clinic, operative notes, and pre- and postoperative imaging studies. RESULTS: The authors identified 41 patients who met the inclusion criteria (age range 14-82 years, mean 42.2 years, standard deviation 22.4 years). The most common presenting symptoms were proptosis and/or partial ptosis (11 cases [27%]) and headache (7 cases [17%]). In 5 (12%) cases, the tumors were primary intraorbital lesions, and in 34 cases (83%) they were secondary. Two patients had metastases to the orbit. The most common lesion types were meningioma (10 cases [24%]) and osteoma (7 cases [17%]). In 24 cases a midline approach through a frontal craniotomy or a subcranial approach was used; in 13 a lateral approach was used; and in 4 a biopsy procedure was performed. Maxillectomy through a Weber-Ferguson approach or a facial degloving approach was added in 5 cases to complete tumor removal. Duration of follow-up was 1-38 months (mean 20 months). None of the patients died as a result of the procedure, and there were relatively few complications. Excluding the patients who underwent orbital exenteration, none of the patients had visual deterioration following surgery, and most had no change in their visual condition. Two patients had temporary diplopia, 1 had a cerebrospinal fluid leak, and 1 had enophthalmos following removal of an orbital osteosarcoma. CONCLUSIONS: Orbital tumors can be treated safely using transcranial approaches in many cases. Preoperative imaging can accurately define the compartments involved and the surgical approach needed for tumor removal. A multidisciplinary team of surgeons facilitates optimal tumor removal and skull base sealing as well as good cosmetic results.