Neuroanatomical MRI study: reference values for the measurements of brainstem, cerebellar vermis, and peduncles

Abstract

Objectives: To set age-specific normal reference values for brainstem, cerebellar vermis, and peduncles measurements and characterize values’ variations according to gender, age, and age by gender interaction. Methods: 565 normal brain magnetic resonance examinations with normal anatomy and signal intensity of the supra and infratentorial structures were categorized into six age groups (infant, child, adolescent, young adult, middle-age adult, and old aged adults). Patients with congenital malformations, gross pathology of the supra or infratentorial brain, brain volume loss, developmental delay, metabolic disorders, and neuropsychological disorders (n = 2.839) were excluded. On midsagittal T1-weighted and axial T2-weighted images specific linear diameters and ratios of the brainstem, cerebellar vermis, and peduncles were attained. Two observers assessed a random sample of 100 subjects to evaluate the inter- and intra observer reproducibility. Intraclass correlation coefficients (ICCs), means ± standard deviation (SD), one, and two-way analysis of variance tests were used in the statistical analysis. Results: Good to excellent inter- and intra observer measurements’ reproducibility were observed, except for the transverse diameter of the midbrain, the anteroposterior diameter of the medulla oblongata at the pontomedullary and cervicomedullary junctions, cerebellar vermis anteroposterior diameter, and thickness of the superior cerebellar peduncle. Age-specific mean values of the investigated measurements were established. A significant gender-related variation was recorded in the anteroposterior diameter of the basis pontis (p = 0.044), the anteroposterior diameter of the medulla oblongata at the cervicomedullary junction (p = 0.044), and cerebellar vermis height (p = 0.018). A significant age-related change was detected in all measurements except the tectal ratio. Age by gender interaction had a statistically significant effect on the tectal ratio, inferior, and middle cerebellar peduncles’ thickness (p = 0.001, 0.022, 0.028, respectively). Conclusion: This study provides age-specific normal mean values for various linear dimensions and ratios of the posterior fossa structures with documentation of measurements’ variability according to gender, age, and their interaction. Advances in knowledge: It provides a valuable reference in the clinical practice for easier differentiation between physiological and pathological conditions of the posterior fossa structures especially various neurodegenerative diseases and congenital anomalies.

Neuroradiological findings in GAA-FGF14ataxia (SCA27B): more than cerebellar atrophy

“…To assess the presence of brainstem atrophy we measured the maximal anteroposterior diameter at the level of the midbrain, midpons, and medulla on sagittal images, and compared to normative values for age according to Metwally et al 10 The corpus callosum thickness was quantified by measuring the maximum width of the body at midpoint and compared to normative values according to Gupta et al 11…”

“…The effect of the patient's age was taken into consideration by comparing the images to standard image series used in a study of a neurologically healthy population. 9 To assess the presence of brainstem atrophy we measured the maximal anteroposterior diameter at the level of the midbrain, midpons, and medulla on sagittal images, and compared to normative values for age according to Metwally et al 10 The corpus callosum thickness was quantified by measuring the maximum width of the body at midpoint and compared to normative values according to Gupta et al 11 We also reviewed and assessed the presence and characteristics of white matter abnormalities on T2-and FLAIR T2-weighted images on all planes, when available, by location (periventricular, subcortical, juxtacortical), lobar involvement (frontal, parietal, temporal, occipital, cerebellar, brainstem), and symmetry. Juxtacortical lesions were defined as lesions in direct contact with the cortical ribbon.…”

On the Cut-Off Value of the Anteroposterior Diameter of the Midbrain Atrophy in Spinocerebellar Ataxia Type 2 Patients

“…The advent of brain imaging studies, which are now considered indispensable, made it possible to demonstrate the atrophy of the cerebellum, brainstem, spinal cord, and brain. This atrophy is even evident in presymptomatic carriers of SCA2 [2,3,13,21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Nuclear magnetic resonance (NMR) imaging is particularly useful due to its excellent tissue discrimination and its superiority over computed axial tomography by eliminating "noise" caused by bony structures in the posterior cranial fossa.…”

“…Perhaps, with the existing low-field MRI scanners, we could have already obtained this threshold, but as of now, it remains to be determined. Reetz et al used the measurement of the maximum diameter of the midbrain as a variable, because this is one of the organs most affected by atrophy in this subtype of ataxia [3,21,[33][34][35]45]. In their study, an efficient method consisting of manual and linear delineation was proposed.…”

Sexual Dimorphism in VEMP peak to trough Latency

“…The vestibular system projects directly to cerebellar vermis (Hitier et al, 2014). Several studies have found that cerebellar vermis is larger in men than women (Raz et al, 1992(Raz et al, , 1998(Raz et al, , 2001Tiemeier et al, 2010), although sometimes the opposite has been found (Luft et al, 1999) and some studies have found no group difference (Rhyu et al, 1999;Bernard et al, 2015;Metwally et al, 2021). Vestibular nuclei span the pons and medulla, which have been investigated in humans using diffusion tensor imaging (Bouhrara et al, 2021).…”