The septum pellucidum and its variants. An MRI study
Increased prevalence of cavum septi pellucidi (CSP) in schizophrenic patients in comparison to healthy subjects was reported previously. Our purpose was to evaluate the prevalence of variants of the septum pellucidum in healthy subjects in three different age groups.
151 healthy subjects, including 46 children (age 6 +/- 4 years), 72 young adults (age 31 +/- 8 years) and 33 elderly adults (age 59 +/- 7 years) were examined with high-resolution MRI. Three observers analysed the images using a standardised protocol. We evaluated the incidences of CSP, cavum vergae (CV) and their length.
CSP was detected in 80% of the cases in the paediatric group and 68% of young adults and in 72% of the elderly adults. A cavum vergae (CV) was noted in 22% of the children, in 39% of the young adults and in 36% of the elderly subjects. There was no significant difference between the age-related groups.
We detected a high prevalence of cavum septi pellucidi without a significant age dependence. Enlarged cava septi pellucidi are rare in healthy subjects.
Available from: Mahmoud M Nasr
- "Notwithstanding, the reported incidence of cavum septi pellucidi varies widely between studies and ranges from 2 to 85%. When a cavum septi pellucidi persists, it is bounded posteriorly by the columns of the fornix and inferiorly by the anterior commissure and the rostrum of the corpus callosum. On the other hand, a cavum vergae is a posterior extension of a cavum septi pellucidi past the columns of the fornix and the foramina of Monro in which the separation of the leaflets of the septum pellucidum continues backward up to the splenium of the corpus callosum. "
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Colloid cysts are usually located at the rostral part of the third ventricle in proximity to the foramina of Monro. Some third ventricular colloid cysts, however, attain large sizes, reach a very high distance above the roof of the third ventricle, and pose some challenges during endoscopic excision. These features led to the speculation that for such a pattern of growth to take place, the points of origin of these cysts should be at areas away from the foramina of Monro at which some anatomical “windows” exist that are devoid of compact, closely apposed forniceal structures.
A review of the literature on anatomical variations of the structures in the vicinity of the roof of the third ventricle and on reported cases with similar features was conducted.
Colloid cysts may grow vertically up past the roof of the third ventricle through anatomical windows devoid of the mechanical restraint of the forniceal structures.
Some anatomical variations of the forniceal structures may allow unusually large sizes and superior vector of growth of a retro- or post-foraminal colloid cyst. Careful preoperative planning and knowledge of the pertinent pathoanatomy of these cysts before endoscopic excision is very important to avoid complications.
Available from: Roberto Colom
- "This variation is also associated with enlargement of the septum pellucidum. Actually, the CC and the septum pellucidum are structurally and functionally related in terms of morphogenesis: the latter is attached to the former, and both share a common embryogenetic process (Born et al. 2004). Attentional control implies selectively attending to certain stimuli while ignoring (or inhibiting) others (Posner and Rothbart 1998). "
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ABSTRACT: Corpus callosum (CC) might be related to cognitive performance because of its role in interhemispheric communication. Previous research has focused mainly on volumetric analyses of the CC, yielding contradictory results to some extent. Shape is an approach that integrates and extends the data obtained with the volumetric methodology. Here, we analyze the relationships between midsagittal CC shape variation and several cognitive measures. 2D coordinates from 102 MRI-scanned young adult human CCs were superimposed through a Procrustes approach. The residual variation was regressed onto 21 cognitive measures completed by the participants. Most of these measures (including general intelligence, working memory, executive functioning, and mental speed) were unrelated to midsagittal CC morphology. However, attentional control did show consistent and significant correlations with CC shape variation. Slower responses in attentional control were systematically associated with more curved and thinner CC, with consequent rotation of the splenium and the genu. Although the magnitude of the correlations suggests a small relationship of midsagittal CC geometry and attention, the results provide interesting clues regarding the links between brain anatomical configuration and human cognitive function.
Available from: Tony J Simon
- "We operationally defined the boundaries of the CSP as follows: anteriorly by the genu of the corpus callosum, superiorly by the body of the corpus callosum, posteriorly by the anterior limb and pillars of the fornix, and inferiorly by the rostrum of the corpus callosum and the anterior commissure. When viewed in the coronal plane, the cavum is triangular with its base at the corpus callosum (Born et al., 2004). Voxels within the tracing boundaries for each slice were then summed to calculate volume in mm 3 . "
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ABSTRACT: Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a result of a hemizygotic microdeletion that results in a variety of impairments in children including greater risk for psychiatric ailments in adulthood. We used high-resolution magnetic resonance imaging to accurately quantify the length and, for the first time, volume, of the cavum septum pellucidum (CSP) in children aged 7 to 14years with 22q11.2DS and typically developing (TD) controls. Significantly greater anteroposterior length and greater CSP volumes were found in children with 22q11.2DS compared with controls. Furthermore, the largest CSP were found only in the 22q11.2DS group and with a much higher incidence than previously reported in the literature. Given the significant midline anomalies in the brains of those affected by 22q11.2DS, large CSP may be a biomarker of atypical brain development. The implication of these larger CSP for cognitive and behavioral development is a topic in need of further investigation.
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