The anterior perforated substance (APS) revisited: Commented anatomical and imagenological views.

INTRODUCTION: Since 2002, when we published our article about the anterior perforated substance (APS), the knowledge about the region has grown enormously. OBJECTIVE: To make a better description of the anatomy of the zone with new dissection material added to the previous, to sustain the anatomical analysis of the MRI employing the SPACE sequence, interacting with our imagenology colleagues. Especially, we aim to identify and topographically localize by MRI the principal structures in APS-substantia innominata (SI). METHOD: The presentation follows various steps: (1) location and boundaries of the zone and its neighboring areas; (2) schematic description of the region with simple outlines; (3) cursory revision of the SI and its three systems; (4) serial images of the dissections of the zone and its vessels, illustrated and completed when possible, by MRI images of a voluntary experimental subject (ES). RESULTS: With this method, we could expose most of the structures of the region anatomically and imagenologically. DISCUSSION: The zone can be approached for dissection with magnification and the habitual microsurgical instruments with satisfactory results. We think that fibers in this region should be followed by other anatomical methods in addition to tractography. The principal structures of ventral striopallidum and extended amygdala (EA) can be identified with the SPACE sequence. The amygdala and the basal ganglion of Meynert (BGM) are easily confused because of their similar signal. Anatomical clues can orient the clinician about the different clusters of the BGM in MRI. CONCLUSIONS: The dissection requires a previous knowledge of the zone and a good amount of patience. The APS is a little space where concentrate essential vessels for the telencephalon, "en passage" or perforating, and neural structures of relevant functional import. From anatomical and MRI points of view, both neural and vascular structures follow a harmonious and topographically describable plan. The SPACE MRI sequence has proved to be a useful tool for identifying different structures in this area as the striatopallidal and EA. Anatomical knowledge of the fibers helps in the search of clusters of the basal ganglion.

Características tomográficas en un paciente con Síndrome de Fahr, a propósito de un caso / Tomographic features in a patient with Fahr syndrome, report of a case

El Síndrome de Fahr o calcificación idiopática de los ganglios basales es una patología neurológica degenerativa de baja frecuencia. Siendo un desorden genético hereditario autosómico dominante, se caracteriza por anormales depósitos de calcio en ciertas zonas del cerebro incluyendo el ganglio basal y la corteza cerebral asociado a síntomas neuropsiquiátricos. Se presenta el caso de un paciente de 31 años de edad que ingresa al servicio de urgencias del Hospital Obrero N°2 presentando crisis convulsivas tónico clónicas generalizadas, disartria, movimientos atetósicos en extremidades superiores e inferiores, al cual se solicitó una tomografía computarizada sin contraste donde se evidencia extensa calcificación bilateral y simétrica de la sustancia blanca que compromete cerebelo, núcleos basales, corona radiada, concluyendo que se trataba de un Síndrome de Fahr .

Fahr's Syndrome or Idiopathic basel ganglion calcification is a infrequent degenerative neurological pathology. It is a genetically auto-somal dominant dysfunction that is characterized by abnormal deposits of calcium in certain areas of the brain including the basal ganglion and the cerebral cortex, it is associated with neuropsychiatric symptoms.Presenting the case of a 31 year-old male patient entering the emergency services with tonic-clonic seizures, dyslalia, dysarthria, athetotic movements of the upper and lower extremities and ataxia. A computed axial tomography without contrast was requested. Extensive bilateral, symmetrical calcification of the white matter was diagnosed that affecting cerebellum, basal ganglia and corona radiate. Based on that evidence Fahr's Syndrome was diagnosed.