Fourth ventricle computed tomography indexes: standardisation and characteristics in neurocysticercosis

Abstract

-Objectives: to propose standardisation of fourth ventricle dimensions and to study its characteristics in neurocysticercosis. Method: a control group (CG) constituted by 114 individuals with normal CT, and 80 patients with neurocysticercosis composed the group with neurocysticercosis (GN). Measures of the inner cranial diameter (Cr), fronto-polar distance between both lateral ventricles (FP), antero-posterior (AP) and latero-lateral (LL) fourth ventricle width based the standardisation of six indexes. Results: AP/Cr, AP/LL and AP/ FP were the more discriminative indexes, presenting in CG the mean values of 0.063, 0.267 and 0.582, respectively. The indexes in GN had values statistically higher than in CG. From GN, 51patients had increased indexes values above 2 standard deviation of the CG mean. AP/Ll was > 1 in 95% of patients with ventricular shunting and in 88% with depression. It also occurred in 73% patients with satisfactory follow-up and in everybody who died. Conclusion: AP/Cr, AP/LL and AP/FP may represent fourth ventricle dimensions.KEY WORDS: fourth ventricle, indexes, computed tomography, standardisation, neurocysticercosis. Índices do IV ventrículo em tomografia computadorizada de crânio: padronização e características na neurocisticercoseRESUMO -Objetivos: propor padrão de normalidade das dimensões do IV ventrículo e estudar suas características em neurocisticercose. Método: em um grupo controle (GC) constituído de 114 indivíduos com tomografias normais e em outro grupo composto de 80 doentes com neurocisticercose (GN), mediram-se a distância fronto-polar de ventrículos laterais (FP) e os diâmetros craniano interno (Cr), ântero-posterior (AP) e látero-lateral (LL) do IV o ventrículo para a padronização de seis índices. Resultados: AP/Cr, AP/LL e AP/FP foram os índices mais discriminatórios e apresentaram, em GC, valores médios de 0,063, 0,267 e 0,582, respectivamente. Em GN os valores foram estatisticamente superiores a GC. Selecionaram-se 51 doentes do GN com índices > 2 desvios-padrão da média em GC. Neles, AP/Ll foi > 1 em 95% doentes com derivação liquórica e em 88% com depressão, ocorrendo em 73% com evolução satisfatória e todos que faleceram. Conclusão: AP/Cr, AP/LL e, principalmente, AP/FP são representativos das dimensões do IV ventrículo.

Age-related Measurements and Indices of Normal Human Brain Fourth Ventricle: A Computed Tomography Study

“…However there mean values showed a significant increase in the last three consecutive age groups (20-> 60) years. These data were consistent with Meese et al (1980), (17) and Agapejev (2002), (10), who found that the fourth ventricle shows a continuous and progressive increase with advancing age. Koller et al (1981), (18), found that the maximal anteroposterior (AP) and laterolateral (LL) width of the fourth ventricle, showed an insignificant increase with advance of age from 20 to 60 years at CT, but they found a significant increase in this parameter thereafter.…”

“…On the other hand the only index that does not suffer influence of age and sex is the (AP/LL) index. Meese (1980), (17) and Agapejev (2002), (10), confirmed these present data and referred the stability of (AP/LL) index to the volumetric difference in the neuroaxis.…”

“…The mean values of AP, LL, CR, AP/CR, AP/ff of the fourth ventricle were higher in males than in females and showed significant differences in some of the mentioned parameters. However AP/LL was the only parameter which showed no difference between males and females as this index considered as sentinel index of the fourth ventricle which showed no changes with age and sex, (Agapejev, 2002), (10).…”

“…CT imaging was conducted without sedation, anesthesia or intravenous contrast administration. The procedure was performed according to Agapejev (10) ; using high resolution scanner with the scanning at an average tilt of 20 o from the cantho-meatal line that extends from the lateral epicanthus of the eye to the external acoustic meatus. Individuals were put in a supine position, centralized, fixed and their heads were placed in the gantry of the apparatus in a slightly hyper-extended position.…”

“…However, AP/LL > 1 was found in all patients with clinical picture of benign intracranial hypertension and in psychiatric alterations as the first and most important manifestation. It also occurred in 86% of patients with cerebrovascular disturbances, in 74% with hydrocephalus, in 71% with epilepsy, in 64% with meningo-encephalitis, and in 50% with migraine like headache (Agapejev, 2002), (10).…”