Infratentorial Volume Research Articles

Nucleus accumbens degeneration in spinocerebellar ataxia type 2: a preliminary study.

Spinocerebellar ataxia type 2 (SCA2) exhibits mainly cerebellar and oculomotor dysfunctions but also, frequently, cognitive impairment and neuropsychological symptoms. The mechanism of the progression of SCA2 remains unclear. This study aimed to evaluate longitudinal structural changes in the brains of SCA2 patients based on atrophy rate. The OpenNeuro Dataset ds001378 was used. It comprises the demographic data and two magnetic resonance images each of nine SCA2 patients and 16 healthy controls. All structural images were preprocessed using FreeSurfer software, and each region's bilateral volume was summed. Atrophy rates were calculated based on the concept of symmetrised percent change and compared between SCA2 patients and healthy controls using non-parametric statistics. As post hoc analysis, correlation analysis was performed between infratentorial volume ratio and the accumbens area atrophy rates in SCA2 patients. There were no significant differences between groups for age, gender, and the time between scans. Statistical analysis indicated a significantly larger atrophy rate of the accumbens area in SCA2 patients than in controls. Additionally, the infratentorial volume ratio and accumbens area atrophy rates showed moderate negative correlation. This study found that nucleus accumbens (NAc) atrophy was significantly accelerated in SCA2 patients. Anatomically, the NAc is densely connected with infratentorial brain regions, so it is reasonable to posit that degeneration propagates from the cerebellum and brainstem to the NAc and other supratentorial areas. Functionally, the NAc is essential for appropriate behaviour, so NAc degeneration might contribute to neuropsychological symptoms in SCA2 patients.

Supratentorial vs infratentorial posterior calvarial distraction osteogenesis for the increase of ICV in children with syndromic or multi-suture craniosynostosis: a retrospective cohort study

PurposeCraniosynostosis is the premature and pathological fusion of calvarial sutures. One modality of surgical treatment of syndromic craniosynostosis is posterior calvarial distraction (PCD). This can be either supratentorial or infratentorial. Currently, supratentorial PCD may be regarded as safer but produces a smaller increase in calvarial volume compared to infratentorial PCD. This study quantifies and compares the effectiveness of supratentorial and infratentorial PCD to help guide surgical decision-making.MethodsThe CT and/or MRI scans of 47 cases of craniosynostosis who underwent PCD from the Birmingham Children’s Hospital (BCH) were converted to sagittal series multi-planar reformatted (MPR) scans for the manual calculation of ICV. The 47 cases were classified as having undergone either supratentorial or infratentorial PCD using lateral plain film radiographs, with 28 and 32 pairs of pre- and post-operative CT/MRI scans reviewed respectively.ResultsA statistically significant difference between supratentorial and infratentorial PCD was observed for the increase in supratentorial volume (STV) (P = 0.0458) and total intracranial volume (TICV) (P = 0.0437), but not for the increase in infratentorial volume (ITV) (P = 0.0697). The relationship for each volume trended towards convergence but was not achieved before the physical limit of 30 mm distraction had been reached. Intraclass correlation coefficient values for agreement of MRI and CT scans for STV, ITV and total ICV were 0.852, 0.864 and 0.854 respectively.ConclusionOur evidence suggests that supratentorial PCD is more effective for increasing ICV in a clinical setting. CT and MRI imaging modalities are acceptably clinically interchangeable for calculating ICV in craniosynostosis.

Surgical outcomes of Supra- Infra Tentorial Extradural Hematoma (SIEDH): A retrospective study from a single institution

IntroductionBicompartmental Supra plus Infratentorial Extra Dural Hematoma (SIEDH) is an uncommon yet important category of Extradural Hematoma (EDH) straddling the transverse sinus. It requires quick decision making and proper surgical evacuation. MethodsWe did a retrospective chart review of all SIEDH cases from prospectively maintained operative database in our institute between 2011 & 2017. Clinical status at discharge and follow up were used to assess outcome. Ordinal regression analysis was used for analysis of factors predicting the outcome. We also describe the surgical procedure we follow at our high-volume trauma center for this unique entity. ResultsWe had 61 operated cases of SIEDH in our series. The median age of the cohort was 30 years (IQR: 21.5–42). Road Traffic Accident was the most common mode of injury (67.2 %). Median pre-operative GCS was 12 (IQR: 9–12). The median volume of SIEDH was 50cc (IQR: 40–70). Mass effect on 4thventricle and brainstem was seen in 47 and 34 patients respectively. An associated fracture was seen in 54 patients. Sinus injury related bleed was noted intra-operatively in 57 % (N = 35). Follow up was available for 60 cases with a median of 130 days. On evaluating with ordinal regression analysis, we found that, the GCS at presentation, pupillary asymmetry, volume of SIEDH, infratentorial volume, blood loss and mass effect on 4thventricle were statistically significant factors affecting GCS at discharge. However, the GCS at presentation, infratentorial volume and blood loss were the only factors determining GOS at follow-up. ConclusionSIEDH are uncommon yet important type of injury type which requires prompt attention and appropriate nuanced approach. Large SIEDH are commonly associated with sinus injury, and large volume blood loss may be anticipated. In addition, SIEDH may be associated with other traumatic brain injuries which may require surgical evacuation.

A systematic quantitative morpho-volumetric analysis in infants with sagittal craniosynostosis and relationship with the severity of scaphocephalic deformity.

Among patients with isolated sagittal synostosis (ISS), the head shape varies considerably in relation to the severity of the abnormality. This study aimed to quantify skull base morphometry and intracranial volume to investigate their relationships with the severity of scaphocephaly. We studied 66 infants with ISS identifying three groups according to the morphological severity of cranial deformity (group I: mild deformity; group II: moderate deformity; group III: severe deformity), by combining two scaphocephaly severity indices as descriptors of the relation of three morphological measurements (length, width and height) We perform a quantitative analysis using high-resolution CT images calculating following parameters: cranial fossae dimensions, supratentorial (ICV) and infratentorial (PCFV) cranial volume, supratentorial (WBV) and infratentorial (PCFBV) brain volume, ICV/WBV, PCFV/PCFBV, supratentorial and infratentorial cerebrospinal fluid (CSF). In all subgroups, anterior and middle skull base lengths were increased, while posterior hemifossae lengths were unchanged. In mild subgroup, ICV/WBV was significantly different and ICV, WBV and CSF supratentorial volume increased (p < 0.05). In moderate and severe subgroups, FCPV/FCPBV was significantly different and CSF infratentorial volume was reduced (p < 0.05); FCPBV was increased only in the severe subgroup (p < 0.05). This morpho-volumetric study provides new insights in understanding the compensatory changes occurring in infants at different stages of scaphocephaly severity. In particular, our study suggests that patients with severe deformity might have an earlier depletion of reserve mechanisms with a reduced compliance of the overall skull during encephalic growth and these patients might require early surgical cranial expansion.

Infratentorial gray matter atrophy and excess in primary craniocervical dystonia

BackgroundPrimary craniocervical dystonia (CCD) is generally attributed to functional abnormalities in the cortico–striato–pallido–thalamocortical loops, but cerebellar pathways have also been implicated in neuroimaging studies. Hence, our purpose was to perform a volumetric evaluation of the infratentorial structures in CCD. MethodsWe compared 35 DYT1/DYT6 negative patients with CCD and 35 healthy controls. Cerebellar volume was evaluated using manual volumetry (DISPLAY software) and infratentorial volume by voxel based morphometry of gray matter (GM) segments derived from T1 weighted 3 T MRI using the SUIT tool (SPM8/Dartel). We used t-tests to compare infratentorial volumes between groups. ResultsCerebellar volume was (1.14 ± 0.17) × 102 cm3 for controls and (1.13 ± 0.14) × 102 cm3 for patients; p = 0.74. VBM demonstrated GM increase in the left I–IV cerebellar lobules and GM decrease in the left lobules VI and Crus I and in the right lobules VI, Crus I and VIIIb. In a secondary analysis, VBM demonstrated GM increase also in the brainstem, mostly in the pons. ConclusionWhile gray matter increase is observed in the anterior lobe of the cerebellum and in the brainstem, the atrophy is concentrated in the posterior lobe of the cerebellum, demonstrating a differential pattern of infratentorial involvement in CCD. This study shows subtle structural abnormalities of the cerebellum and brainstem in primary CCD.

Differential regional brain growth and rotation of the prenatal human tentorium cerebelli

Folds of dura mater, the falx cerebri and tentorium cerebelli, traverse the vertebrate endocranial cavity and compartmentalize the brain. Previous studies suggest that the tentorial fold has adopted an increasingly important role in supporting the increased load of the cerebrum during human evolution, brought about by encephalization and an adaptation to bipedal posture. Ontogenetic studies of the fetal tentorium suggest that its midline profile rotates inferoposteriorly towards the foramen magnum in response to disproportionate growth of the cerebrum. This study tests the hypothesis that differential growth of the cerebral and cerebellar components of the brain underlies the inferoposterior rotation of the tentorium cerebelli during human fetal development. Brain volumes and tentorial angles were taken from high-resolution magnetic resonance images of 46 human fetuses ranging from 10 to 29 gestational weeks. Apart from the expected increases of both supratentorial and infratentorial brain volumes with age, the results confirm previous studies showing a significant relative enlargement of the supratentorial volume. Correlated with this enlargement was a rotation of the midline section of the tentorium towards the posterior cranial base. These findings support the concept that increases of supratentorial volume relative to infratentorial volume affect an inferoposterior rotation of the human fetal tentorium cerebelli. These results are discussed in the context of the role played by the tentorium cerebelli during human evolution and underline implications for phylogenetic and ontogenetic models of encephalization.

Assessment of posterior fossa damage in MS using MRI.

In multiple sclerosis (MS), brain stem and cerebellum are frequent sites of damage in clinically isolated syndromes at presentation and it is likely that lesions located in such structures can have an important impact on the development of disability in the definite forms of the disease. In patients presented with isolated brain stem syndromes, the symptomatic lesion was often not detected by magnetic resonance (MR) imaging. But patients with asymptomatic infratentorial lesions progressed to clinically definite MS in 65% of cases. Infratentorial lesions are included in various MR criteria designed to assist in the differential diagnosis of MS lesions from incidental lesions, to differentiate MS from subcortical encephalopathic arteriopathy. The preferred MR sequence to visualize infratentorial lesions is the fast spin echo sequence. It is preferred to conventional spin echo and fast fluid attenuated inversion recovery sequences because of its relatively short acquisition time and good sensitivity. The correlation between disability and infratentorial lesion load on T2 weighted sequences is controversial. However, it was recently shown that the correlations between clinical measures and T1 lesion load, histogram magnetization transfer ratio and peak positions, and infratentorial volume measurements are strong. These findings suggest that one of the major factors in the development of disability in patients with MS is the pathological damage in clinically eloquent sites such as the brain stem and cerebellum.