[Developmental amnesia and early brain damage: neuropsychology and neuroimaging]. / Amnesia del desarrollo y daño cerebral temprano: neuropsicologia y neuroimagen.

AIM: To contribute to neuropsychological profiling of developmental amnesia subsequent to bilateral damage to both hippocampi in early age. SUBJECTS AND METHODS: The total sample of 24 schoolchildren from both sexes is distributed in three groups: perinatal hypoxic-ischaemic encephalopathy and everyday complaints of memory in school age (n = 8); perinatal hypoxic-ischaemic encephalopathy without memory complaints (n = 7); and a group of typically developing (n = 9). All participants in every groups did have normal general intelligence and attention. Both clinical groups had, as another clinical consequence, spastic cerebral palsy (diplegia). Neuropsychological exam consisted on tests of general intelligence, attentional abilities, declarative memory and semantic knowledge. All participants had a brain magnetic resonance image and spectroscopy of hippocampi. Scheltens criteria were used for visual estimation of hippocampal atrophy. Parametric and non-parametric statistical contrasts were made. RESULTS: Despite preservation of semantic and procedural learning, declarative-episodic memory is impaired in the first group versus the other two groups. A significant proportion of bilateral hippocampal atrophy is only present in the first group versus the other two non-amnesic groups using Scheltens estimation on MRI. Two cases without evident atrophy did have diminished NAA/(Cho + Cr) index in both hippocampi. CONCLUSIONS: Taken together, these results contribute to delineate developmental amnesia as an specific impairment due to early partial bihippocampal damage, in agreement with previous studies. After diagnosis of developmental amnesia, a specific psychoeducational intervention must be made; also this impairment could be candidate for pharmacological trials in the future.

TITLE: Amnesia del desarrollo y daño cerebral temprano: neuropsicologia y neuroimagen.Objetivo. Contribuir a la descripcion de la amnesia del desarrollo como sindrome especifico en niños que sufrieron agresion temprana, pero no masiva, de ambos hipocampos. Sujetos y metodos. Muestra de 24 escolares de ambos sexos, de 6-16 años de edad. Se distribuye en tres grupos: pacientes afectos de encefalopatia hipoxico-isquemica perinatal, con paralisis cerebral espastica, inteligencia normal y fallos de memoria (n = 8); pacientes con similares caracteristicas, pero sin quejas de memoria (n = 7); y escolares sanos sin antecedentes de riesgo (n = 9) como grupo control. Se aplican escalas y tests para comprobar la normalidad intelectual y atencional, y para medir el perfil de rendimiento en tareas de memoria. En todos los sujetos, mediante resonancia magnetica, se estima la presencia y grado de atrofia hipocampica con la escala de Scheltens, y se calcula el indice espectroscopico NAA/(Cho + Cr). Resultados. El perfil neuropsicologico de los ocho pacientes del primer grupo es claramente sugestivo de amnesia del desarrollo, que contrasta con la normalidad en los otros grupos. En siete escolares con amnesia se constata bilateralmente algun grado de atrofia bihipocampica o disminucion significativa del indice NAA/(Cho + Cr). Conclusiones. La amnesia del desarrollo se caracteriza por afectacion de la memoria episodica con preservacion del aprendizaje semantico y procedimental. Se explica por daño parcial bihipocampico temprano. El correcto diagnostico permite una intervencion psicoeducativa especifica. En el futuro cabria ensayar terapias farmacologicas asociadas a la intervencion psicoeducativa.

Intraoperative 3 tesla magnetic resonance imaging: our experience in tumors. / Resonancia magnética intraoperatoria de 3 teslas: Nuestra experiencia en patología tumoral.

OBJECTIVE: To report our experience in the use of 3 tesla intraoperative magnetic resonance imaging (MRI) in neurosurgical procedures for tumors, and to evaluate the criteria for increasing the extension of resection. MATERIAL AND METHODS: This retrospective study included all consecutive intraoperative MRI studies done for neuro-oncologic disease in the first 13 months after the implementation of the technique. We registered possible immediate complications, the presence of tumor remnants, and whether the results of the intraoperative MRI study changed the surgical management. We recorded the duration of surgery in all cases. RESULTS: The most common tumor was recurrent glioblastoma, followed by primary glioblastoma and metastases. Complete resection was achieved in 28%, and tumor remnants remained in 72%. Intraoperative MRI enabled neurosurgeons to improve the extent of the resection in 85% of cases. The mean duration of surgery was 390±122minutes. CONCLUSION: Intraoperative MRI using a strong magnetic field (3 teslas) is a valid new technique that enables precise study of the tumor resection to determine whether the resection can be extended without damaging eloquent zones. Although the use of MRI increases the duration of surgery, the time required decreases as the team becomes more familiar with the technique.

[Neuroimaging in brain tumors]. / Neuroimagen de los tumores cerebrales.

Advances in neuroimaging have modified diagnosis, treatment and clinical management of brain tumors. However, neuropathological study remains necessary in order to get the best clinical management. Surgery and radiotherapy planning are imaging-dependent procedures, and MRI is the standard imaging modality for determining precisely tumor location and its anatomical relationship with surrounding brain structures. In high-grade tumors it has been accepted that tumoral areas with contrast uptake in CT, or T1-weighted MRI contrast enhancement corresponds to solid tumor. However, relationship between MRI and invasive tumor areas remains less defined. Therefore, it is generally accepted that conventional MRI is not sufficient to delineate the real extension of brain tumors. In recent years, PET using 18FDG and amino acid radiotracers ((11)C-Methionine, (18)FDOPA, (18)FET) and SPECT with (201-)Thallium, as well as advanced MRI sequences (Perfusion, Diffusion-weighted, Diffusion tensor imaging and tractography), and functional MRI, have added important complementary information in the characterization, therapy planning and recurrence differential diagnosis of brain tumors. In this continuing education review of neuroimaging in brain tumors, technical aspects and clinical applications of different imaging modalities are approached in a multidisciplinary way.

The use of tooth thickness in predicting intermaxillary tooth-size discrepancies.

Intermaxillary tooth-size discrepancies can be assessed using a diagnostic setup or predicted using a mathematical formula, such as the Bolton analysis. However, variations in tooth thickness may produce inaccuracies in the Bolton analysis ratio. To date, no method for incorporating tooth thickness into discrepancy prediction has been proposed. The purpose of this study was to design and test a new method of predicting anterior tooth-size discrepancy that takes into account tooth thickness and width. Forty-four positioner setup models were set to ideal overbite (2.5 mm) and occlusion (Class I canine relationship). Interproximal gaps between the maxillary or mandibular central incisors were allowed in order to optimize tip and torque. The mesiodistal width of all anterior teeth and the labiolingual thickness of the maxillary incisors were measured on these idealized setups to the nearest 0.1 mm. Actual intermaxillary anterior ratios were then calculated. A new method of prediction was developed by assuming a linear relationship between tooth thickness and ideal intermaxillary ratio. Errors in Bolton's method were compared with the new method. The results showed wide variations in mesiodistal tooth widths, tooth thicknesses, and intermaxillary anterior ratios in orthodontically treated patients. The correlation coefficient between the intermaxillary ratio and tooth thickness was r = 0.68 when tooth thickness was < 2.75 mm, and r = 0.28 when tooth thickness was > or = 2.75 mm. The mean absolute errors in predicting the actual intermaxillary ideal ratio was 1.29 +/- 0.81 for Bolton's ratio and 0.84 +/- 0.46 for the new prediction formula. These new formulas were better than Bolton's ratio in predicting tooth-size discrepancies (p = 0.003). Tooth thickness combined with mesiodistal width may be useful in predicting intermaxillary tooth-size discrepancies.