WILLIAM OMAR CONTRERAS LOPEZ
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- Aesthetically optimal deep brain stimulation technique in patients with alopecia(2015) FONOFF, Erich Talamoni; TEIXEIRA, Manoel Jacobsen; NASCIMENTO, Clarissa Nobrega Gambarra; LOPEZ, William Omar
- Correlation of F-18-fluoroethyl tyrosine positron-emission tomography uptake values and histomorphological findings by stereotactic serial biopsy in newly diagnosed brain tumors using a refined software tool(2015) LOPEZ, William Omar Contreras; CORDEIRO, Joacir Graciolli; ALBICKER, Ulrich; DOOSTKAM, Soroush; NIKKHAH, Guido; KIRCH, Robert D.; TRIPPEL, Michael; REITHMEIER, Thomas R.Background: Magnetic resonance imaging (MRI) is the standard neuroimaging method to diagnose neoplastic brain lesions, as well as to perform stereotactic biopsy surgical planning. MRI has the advantage of providing structural anatomical details with high sensitivity, though histological specificity is limited. Although combining MRI with other imaging modalities, such as positron-emission tomography (PET), has proven to increment specificity, exact correlation between PET threshold uptake ratios (URs) and histological diagnosis and grading has not yet been described. Objectives: The aim of this study was to correlate exactly the histopathological criteria of the biopsy site to its PET uptake value with high spatial resolution (mm(3)), and to analyze the diagnostic value of PET using the amino acid O-(2-[F-18] fluoroethyl)-l-tyrosine (F-18-FET) PET in patients with newly diagnosed brain lesions in comparison to histological findings obtained from stereotactic serial biopsy. Patients and methods: A total of 23 adult patients with newly diagnosed brain tumors on MRI were enrolled in this study. Subsequently to diagnoses, all patients underwent a F-18-FET PET-guided stereotactic biopsy, using an original newly developed software module, which is presented here. Conventional MRI, stereotactic computed tomography series, and F-18-FET PET images were semiautomatically fused, and hot-spot detection was performed for target planning. UR was determined using the uptake value from the biopsy sites in relation to the contralateral frontal white matter. UR values >= 1.6 were considered positive for glioma. High-grade glioma (HGG) was suspected with URs >3.0, while low-grade glioma (LGG) was suspected with URs between 1.6 and 3.0. Stereotactic serial biopsies along the trajectory at multiple sites were performed in millimeter steps, and the FET URs for each site were correlated exactly with a panel of 27 different histopathological markers. Comparisons between FET URs along the biopsy trajectories and the histological diagnoses were made with Pearson product-moment correlation coefficients. Analysis of variance was performed to test for significant differences in maximum UR between different tumor grades. Results: A total of 363 biopsy specimens were taken from 23 patients by stereotactic serial biopsies. Histological examination revealed eight patients (35%) with an LGG: one with a World Health Organization (WHO)-I lesion and seven with a WHO-II lesion. Thirteen (57%) patients revealed an HGG (two with a WHO-III and three with a WHO-IV tumor), and two patients (9%) showed a process that was neither HGG nor LGG (group X or no-grade group). The correlation matrix between histological findings and the UR revealed five strong correlations. Low cell density in tissue samples was found to have a significant negative correlation with the measured cortical uptake rate (r=-0.43, P=0.02), as well as moderate cell density (r=-0.48, P=0.02). Pathological patterns of proliferation (r=0.37, P=0.04), GFAP (r=0.37, P=0.04), and Olig2 (r=0.36, P=0.05) showed a significant positive correlation with cortical URs. Analysis of variance tests showed a significant difference between the LGG and the HGG groups (F=8.27, P<0.002), but no significant differences when differentiating between the X group and the HGG (P=0.2)/LGG (P=0.8) groups, nor between the no-grade group and the WHO-I group. Conclusion: F-18-FET PET is a valuable tool, as it allows the differentiation of HGGs from LGGs. Its use is not limited to preoperative evaluation; it may also refine biopsy targeting and improve tumor delimitation for radiotherapy. Histology is still necessary, and remains the gold standard for definitive diagnosis of brain lesions.
article 11 Citação(ões) na Scopus Pain Relief in CRPS-II after Spinal Cord and Motor Cortex Simultaneous Dual Stimulation(2016) LOPEZ, William O. C.; BARBOSA, Danilo C.; TEIXEIRA, Manoel J.; PAIZ, Martin; MOURA, Leonardo; MONACO, Bernardo A.; FONOFF, Erich T.We describe a case of a 30-year-old woman who suffered a traumatic injury of the right brachial plexus, developing severe complex regional pain syndrome type II (CRPS-II). After clinical treatment failure, spinal cord stimulation (SCS) was indicated with initial positive pain control. However, after 2 years her pain progressively returned to almost baseline intensity before SCS. Additional motor cortex electrode implant was then proposed as a rescue therapy and connected to the same pulse generator. This method allowed simultaneous stimulation of the motor cortex and SCS in cycling mode with independent stimulation parameters in each site. At 2 years follow-up, the patient reported sustained improvement in pain with dual stimulation, reduction of painful crises, and improvement in quality of life. The encouraging results in this case suggests that this can be an option as add-on therapy over SCS as a possible rescue therapy in the management of CRPS-II. However, comparative studies must be performed in order to determine the effectiveness of this therapy.- Optical coherence tomography imaging of the basal ganglia: feasibility and brief review(2015) LOPEZ, W. O. Contreras; ANGELOS, J. S.; MARTINEZ, R. C. R.; TAKIMURA, C. K.; TEIXEIRA, M. J.; LEMOS NETO, P. A.; FONOFF, E. T.Optical coherence tomography (OCT) is a promising medical imaging technique that uses light to capture real-time cross-sectional images from biological tissues in micrometer resolution. Commercially available optical coherence tomography systems are employed in diverse applications, including art conservation and diagnostic medicine, notably in cardiology and ophthalmology. Application of this technology in the brain may enable distinction between white matter and gray matter, and obtainment of detailed images from within the encephalon. We present, herein, the in vivo implementation of OCT imaging in the rat brain striatum. For this, two male 60-day-old rats (Rattus norvegicus, Albinus variation, Wistar) were stereotactically implanted with guide cannulas into the striatum to guide a 2.7-French diameter high-definition OCT imaging catheter (Dragonfly (TM), St. Jude Medical, USA). Obtained images were compared with corresponding histologically stained sections to collect imaging samples. A brief analysis of OCT technology and its current applications is also reported, as well as intracerebral OCT feasibility on brain mapping during neurosurgical procedures.
- Embryonic stem cells in neurology - current clinical transplantation trials in Parkinson's (PD) and Huntington's (HD) disease(2014) LOPEZ, William Omar Contreras; NIKKHAH, Guido; MACIACZYK, Jaroslaw