Preoperative tractography algorithm for safe resection of tumors located in the descending motor pathways zone.

Background: Diffusion tensor imaging (DTI) tractography facilitates maximal safe resection and optimizes planning to avoid injury during subcortical dissection along descending motor pathways (DMPs). We provide an affordable, safe, and timely algorithm for preoperative DTI motor reconstruction for gliomas adjacent to DMPs. Methods: Preoperative DTI reconstructions were extracted from a prospectively acquired registry of glioma resections adjacent to DMPs. The surgeries were performed over a 7-year period. Demographic, clinical, and radiographic data were extracted from patients' electronic medical records. Results: Nineteen patients (12 male) underwent preoperative tractography between January 1, 2013, and May 31, 2020. The average age was 44.5 years (range, 19-81 years). A complete radiological resection was achieved in nine patients, a subtotal resection in five, a partial resection in three, and a biopsy in two. Histopathological diagnoses included 10 patients with high-grade glioma and nine with low-grade glioma. A total of 16 perirolandic locations (10 frontal and six frontoparietal) were recorded, as well as two in the insula and one in the basal ganglia. In 9 patients (47.3%), the lesion was in the dominant hemisphere. The median preoperative and postoperative Karnofsky Performance Scores were 78 and 80, respectively. Motor function was unchanged or improved over time in 15 cases (78.9%). Conclusion: This protocol of DTI reconstruction for glioma removal near the DMP shows good results in low-term neurological functional outcomes.

Neuroanatomía funcional de la escala de coma de Glasgow / Functional neuroanatomy of the Glasgow coma scale

Introducción: La escala de coma de Glasgow (ECG) es una escala mundialmente reconocida para la clasificación de pacientes con trauma craneoencefálico de acuerdo a su compromiso neurológico. Esta escala evalúa la apertura ocular, la respuesta verbal y la respuesta motora. La neuroanatomía funcional representa un compromiso secuencial para el descenso en el puntaje de cada uno de estos ítems. El objetivo de esta revisión es describir la anatomía del sistema reticular activador ascendente (SRAA), la anatomía funcional del lenguaje, la anatomía del tallo cerebral y de las vías motoras que representan cada ítem evaluado por la ECG. Materiales y métodos: Se hizo una revisión narrativa bibliográfica de las principales vías para cada ítem de la ECG. Resultados: Las principales vías en relación con la apertura ocular se concentran en las vías del SRAA, las vías de la respuesta verbal incluyen las vías del lenguaje y las vías que provienen del putamen y del cerebelo que regulan la emisión del lenguaje, mientras que las vías que regulan la respuesta motora principalmente se relacionan con la vía piramidal, el sistema rubro-espinal y vestíbulo-espinal. Conclusiones: El descenso del puntaje en los tres ítems que evalúa la ECG se relacionan con vías específicas que predominan en los ganglios basales y en el tallo cerebral.

Introduction: The Glasgow Coma Scale (GCS) is a globally recognized scale for the classification of patients with traumatic brain injury according to their neurological impairment. This scale evaluates the ocular opening, the verbal response and the motor response. Functional neuroanatomy represents a sequential decrease in the score of each of these items. The objective of this review is to describe the anatomy of the ascending reticular activating system (ARAS), the functional anatomy of the language, and the anatomy of the brainstem and the motor pathways that represent each item evaluated by the GCS. Materials and methods: A narrative literature review of the main routes for each item of the scale was performed. Results: The main pathways in relation to the ocular opening are concentrated in the ARAS, the verbal response pathways include the language pathways and the connections that come from the putamen and the cerebellum that regulate the production of the language, while the pathways that regulate the motor response mainly relate to the pyramidal tract, the rubro-spinal and vestibulo-spinal systems. Conclusions: The decline of the score in the three items that evaluates the GCS is related to specific pathways that predominate in the basal ganglia and in the brainstem.

Identification of Preoperative Language Tracts for Intrinsic Frontotemporal Diseases: A Pilot Reconstruction Algorithm in a Middle-Income Country.

OBJECTIVE: Diffusion tensor imaging (DTI) tractography provides useful information that can be used to optimize surgical planning and help avoid injury during subcortical dissection of eloquent tracts. The objective is to provide a safe, timely, and affordable algorithm for preoperative DTI language reconstruction for intrinsic frontotemporal diseases. METHODS: We reviewed a prospectively acquired database of preoperative DTI reconstruction for resection of left frontotemporal lesions over 3 years at Hospital de San José and Hospital Infantil Universitario San José, Fundación Universitaria de Ciencias de la Salud, Bogota, Colombia. Preoperative and postoperative clinical and radiographic features were determined from retrospective chart review. A comprehensive review of the structural and functional anatomy of the language tracts was performed. Separate reconstruction of both ventral (semantic) and dorsal (phonologic) stream pathways is described: arcuate fasciculus, superior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and inferior longitudinal fasciculus. RESULTS: Between January 2015 and January 2018, 44 tumor cases were found to be resected with preoperative fiber tracking planning and neuronavigation-guided surgery. Ten patients (7 women, 3 men) aged 28-65 years underwent resection of an intrinsic frontotemporal lesion with preoperative DTI tractography reconstruction of language tracts. Eight cases (80%) were high-grade gliomas and 2 (20%) were cavernous malformations. In 5 cases (50%), the lesion was in the frontal lobe and in 5 (50%), it was in the temporal lobe. The extent of resection was classified as gross total resection (100%), subtotal resection (>90%), or partial resection (<90%). Gross total resection was achieved in 5 cases (50%), subtotal resection was achieved in 4 cases (40%), and partial resection in the remaining case (10%). Compromised tracts included superior longitudinal fasciculus in 7 (70%), inferior longitudinal fasciculus in 4 (40%), the arcuate fasciculus in 3 (30%), and uncinate fasciculus in 1 (10%). Language function was unchanged or improved in 90% of patients. New-onset postoperative language decline occurred in 1 patient, who recovered transient phonemic paraphasias 1 month after resection. The mean follow-up time was 7 months (range, 4-12 months). Residual tumors were treated with radiation and/or with chemotherapy as indicated in an outpatient setting. CONCLUSIONS: We present a safe and efficacious preoperative DTI language reconstruction algorithm that could be used as a feasible treatment strategy in a challenging subset of tumors in low- to middle-income countries.

Recovery of consciousness after a brainstem cavernous malformation hemorrhage: A descriptive study of preserved reticular activating system with tractography.

The aim of this study is to describe the imaging features, the relevant anatomy, and the fractional anisotropy (FA) values in diffusion tensor tractography (DTT) of the ascending reticular activating system (ARAS) fiber tracts in 2 patients who recovered from initial altered consciousness after presenting with a brainstem cavernous malformation (BSCM) hemorrhage. A DTT was performed in 2 patients with impaired consciousness after a brainstem cavernous malformation hemorrhage. A 1.5 T scanner was used to obtain the axial tensors. Post-processing was performed and the mean FA values were recorded. The FA maps were used to seed the following regions of interest: the ventromedial midbrain, the anterior thalamus bilaterally, and the hypothalamus bilaterally. The first case presented with posterior displacement of the dorsal raphè fiber tracts, with preservation of all the ascending reticular activating fiber tracts and spontaneous recovery of consciousness after 20 days. The second case presented with no destruction but also had posterior displacement of the inferior dorsal raphè fiber tracts, with recovery of consciousness 1 month after resection surgery. Described in this study are affected fibers of the ARAS, as well as the FA value abnormalities in 2 patients, with recovery of a transient disorder of consciousness after a BSCM hemorrhage.

Técnica de la artrorresonancia magnética de hombro / Thecnic of arthro magnetic resonance of shoulder

En este artículo se revisa con detalle la técnica de punción intraarticular, los materiales y el protocolo que debe seguirse en la realización de la artrorresonancia magnética de hombro después de la experiencia en un centro diagnóstico con, aproximadamente, unos doscientos pacientes en cinco años. Luego de analizar la información, se concluye que se han obtenido buenos resultados técnicos y sin complicaciones, y que esta técnica sirve como modelo para otros centros de diagnóstico.