MRI morphometry of the anterior and posterior cerebellar vermis and its relationship to sensorimotor and cognitive functions in children.

INTRODUCTION: The human cerebellum emerges as a posterior brain structure integrating neural networks for sensorimotor, cognitive, and emotional processing across the lifespan. Developmental studies of the cerebellar anatomy and function are scant. We examine age-dependent MRI morphometry of the anterior cerebellar vermis, lobules I-V and posterior neocortical lobules VI-VII and their relationship to sensorimotor and cognitive functions. METHODS: Typically developing children (TDC; n=38; age 9-15) and healthy adults (HAC; n=31; 18-40) participated in high-resolution MRI. Rigorous anatomically informed morphometry of the vermis lobules I-V and VI-VII and total brain volume (TBV) employed manual segmentation computer-assisted FreeSurfer Image Analysis Program [http://surfer.nmr.mgh.harvard.edu]. The neuropsychological scores (WASI-II) were normalized and related to volumes of anterior, posterior vermis, and TBV. RESULTS: TBVs were age independent. Volumes of I-V and VI-VII were significantly reduced in TDC. The ratio of VI-VII to I-V (∼60%) was stable across age-groups; I-V correlated with visual-spatial-motor skills; VI-VII with verbal, visual-abstract and FSIQ. CONCLUSIONS: In TDC neither anterior I-V nor posterior VI-VII vermis attained adult volumes. The "inverted U" developmental trajectory of gray matter peaking in adolescence does not explain this finding. The hypothesis of protracted development of oligodendrocyte/myelination is suggested as a contributor to TDC's lower cerebellar vermis volumes.

Corpus Callosum Length and Cerebellar Vermian Height in Fetal Growth Restriction.

INTRODUCTION: Growth-restricted fetuses may have changes in their neuroanatomical structures that can be detected in prenatal imaging. We aim to compare corpus callosal length (CCL) and cerebellar vermian height (CVH) measurements between fetal growth restriction (FGR) and control fetuses and to correlate them with cerebral Doppler velocimetry in growth-restricted fetuses. METHODS: This was a prospective cohort of FGR after 20 weeks of gestation with ultrasound measurements of CCL and CVH. Control cohort was assembled from fetuses without FGR who had growth ultrasound after 20 weeks of gestation. We compared differences of CCL or CVH between FGR and controls. We also tested for the correlations of CCL and CVH with middle cerebral artery (MCA) pulsatility index (PI) and vertebral artery (VA) PI in the FGR group. CCL and CVH measurements were adjusted by head circumference (HC). RESULTS: CCL and CVH were obtained in 68 and 55 fetuses, respectively. CCL/HC was smaller in FGR fetuses when compared to control fetuses (difference = 0.03, 95% CI: [0.02, 0.04], p < 0.001). CVH/HC was larger in FGR fetuses compared to NG fetuses (difference = 0.1, 95% CI: [-0.01, 0.02], p = < 0.001). VA PI multiples of the median were inversely correlated with CVH/HC (rho = -0.53, p = 0.007), while CCL/HC was not correlated with VA PI. Neither CCL/HC nor CVH/HC was correlated with MCA PI. CONCLUSIONS: CCL/HC and CVH/HC measurements show differences in growth-restricted fetuses compared to a control cohort. We also found an inverse relationship between VA PI and CVH/HC. The potential use of neurosonography assessment in FGR assessment requires continued explorations.

A genetic variant in the MAST1 gene is associated with mega-corpus-callosum syndrome with hypoplastic cerebellar vermis, in a fetus.

BACKGROUND: Mega-corpus-callosum syndrome with cerebellar hypoplasia and cortical malformations is a rare neurological disorder that is associated with typical clinical and imaging features. The syndrome is caused by pathogenic variants in the MAST1 gene, which encodes a microtubule-associated protein that is predominantly expressed in postmitotic neurons in the developing nervous system. METHODS: Fetal DNA from umbilical cord blood samples and genomic DNA from peripheral blood lymphocytes were subjected to whole-exome sequencing. The potential causative variants were verified by Sanger sequencing. RESULTS: A 26-year-old primigravid woman was referred to our prenatal center at 25 weeks of gestation due to abnormal ultrasound findings in the brain of the fetus. The brain abnormalities included wide cavum septum pellucidum, shallow and incomplete bilateral lateral fissure cistern, bilateral dilated lateral ventricles, hyperplastic corpus callosum, lissencephaly, and cortical dysplasia. No obvious abnormalities were observed in the brainstem or cerebellum hemispheres, but the cerebellum vermis was small. Whole-exome sequencing identified a de novo, heterozygous missense variant, c.695T>C(p.Leu232Pro), in the MAST1 gene and a genetic diagnosis of mega-corpus-callosum syndrome was considered. CONCLUSION: This study is the first prenatal case of MAST1-related disorder reported in the Chinese population and has expanded the mutation spectrum of the MAST1 gene.

Hydrocephalus associated with a molar tooth sign: A distinct subtype of Joubert syndrome.

Hydrocephalus is rarely described in Joubert-Boltshauser syndrome (JBTS). The aim of this study was to investigate whether this association is a chance occurrence or potentially signifies a new phenotypic subtype. The databases of Wolfson Medical Center, Sourasky Medical Center, and EB's personal collection were reviewed. Records from an additional family were obtained from RG. The patients' medical records, prenatal ultrasounds, and magnetic resonance imaging were assessed. In addition, we reviewed the medical literature for the association of ventriculomegaly/hydrocephalus (VM/HC) in JBTS. Only seven cases (from five families) were found with prenatal onset of VM/HC, diagnosed during the second trimester; three pregnancies were terminated, one was stillborn and three were born, of which one died within a week, and another died at the age of 6 years. Additional central nervous system findings included dysgenesis of the corpus callosum, delayed sulcation, polymicrogyria, and pachygyria. We found 16 publications describing 54 patients with JBTS and VM/HC: only five were diagnosed at birth and three were diagnosed prenatally. Hydrocephalus is extremely rare in JBTS. The recurrence of this association, reported in several publications in multiple family members, suggests that it might represent a new phenotypic subtype of JBTS possibly associated with specific genes or variants. Further genetic studies are needed to confirm this hypothesis. WHAT THIS PAPER ADDS: The association of fetal hydrocephalus with Joubert-Boltshauser syndrome (JBTS) is very rare but not a chance association. This association represents a new phenotypic subtype of JBTS possibly linked to specific genes or variants.

Case report and systematic review of cerebellar vermis alterations in psychosis.

INTRODUCTION: Cerebellar alterations, including both volumetric changes in the cerebellar vermis and dysfunctions of the corticocerebellar connections, have been documented in psychotic disorders. Starting from the clinical observation of a bipolar patient with cerebellar hypoplasia, the purpose of this review is to summarize the data in the literature about the association between hypoplasia of the cerebellar vermis and psychotic disorders [schizophrenia (SCZ) and bipolar disorder (BD)]. METHODS: A bibliographic search on PubMed has been conducted, and 18 articles were finally included in the review: five used patients with BD, 12 patients with SCZ and one subject at psychotic risk. RESULTS: For SCZ patients and subjects at psychotic risk, the results of most of the reviewed studies seem to suggest a gray matter volume reduction coupled with an increase in white matter volumes in the cerebellar vermis, compared to healthy controls. Instead, the results of the studies on BD patients are more heterogeneous with evidence showing a reduction, no difference or even an increase in cerebellar vermis volume compared to healthy controls. CONCLUSIONS: From the results of the reviewed studies, a possible correlation emerged between cerebellar vermis hypoplasia and psychotic disorders, especially SCZ, ultimately supporting the hypothesis of psychotic disorders as neurodevelopmental disorders.

Reference Ranges for Vermis Biometry on Prenatal Ultrasound: Systematic Review and Meta-Analysis.

PURPOSE: To conduct a systematic review and meta-analysis of published nomograms for fetal vermis biometry. MATERIALS AND METHODS: A structured literature search was conducted to identify studies that reported normal measurements of the fetal vermis. A customized quality assessment tool was used to review the selected articles. Random effects meta-analysis was used to calculate normal ranges for vermian craniocaudal diameter, anteroposterior diameter, and surface area. RESULTS: A total of 21 studies were included for qualitative review and 3 studies were included for quantitative synthesis. The 3 included articles comprised a total of 10 910 measurements from gestational ages 17-35 weeks. The quality assessment demonstrated that there was generally poor reporting regarding maternal characteristics and neonatal outcomes. Except for one article with a large sample size, the mean number of fetuses per week of gestational age was 15.9, with the lowest number being 5. There was significant statistical heterogeneity. Non-visualization rates ranged from 0-35.4 %. The craniocaudal diameter (reported in 3 articles) increased from a mean of 7.90 mm (95 % confidence interval [CI] 7.42, 8.38) at 17 weeks to 21.90 mm (95 % CI 20.63, 23.16) at 35 weeks gestation. The anteroposterior diameter (reported in 2 articles) increased from 6.30 mm (95 % CI 5.42, 7.18) at 17 weeks to 15.85 (95 %CI 15.49, 16.21) at 32 weeks. CONCLUSION: Reference ranges for vermis biometry across gestation based on meta-analysis of existing references are provided. However, because many of the underlying studies suffered from significant methodological issues, the ranges should be used with caution.

First occurrence of Arnold Chiari type II malformation and associated abnormalities in a Gir calf produced in vitro from Brazil - case report / [Primeira ocorrência de malformação de Arnold Chiari tipo II e anormalidades associadas em uma bezerra Gir de produção in vitro no Brasil - relato de caso]

This study characterized the clinical, radiological, ultrasound, and necroscopic findings of a case of Arnold-Chiari type II malformation in a Gir breed calf from Brazil. The animal was hospitalized at sixty days of age, in permanent sternal recumbency, cutaneous appendix at the 4th lumbar vertebra and kyphoscoliosis of the caudal and lumbosacral thoracic spine. Radiographic examination of the spine and skull revealed spina bifida and suspected occipital hypoplasia. Upon examination of myelography with an injection of lumbar and atlantooccipital contrast, it was possible to visualize the meningocele at the 4th lumbar vertebra region and findings at the rhombencephalon level of increased regional pressure with failure to fill the contrast in the posterior fossa, in the presence of clear demarcation of the circumvolutions of the cerebral cortex and the subarachnoid space of the cervical spinal cord. Ultrasonographic examination of the cerebellum showed an insinuation of the cerebellar worm through the foramen magnum. The animal did not show changes in complete blood count, biochemical series, and cerebrospinal fluid and was negative for Pestivirus. There was a worsening of the clinical conditions and the animal died. This malformation of unknown etiology must be studied as a differential diagnosis of the nervous system disorders.(AU)

Este estudo caracterizou os achados clínicos, radiológicos, ultrassonográficos e necroscópicos de um caso de malformação de Arnold-Chiari tipo II em uma bezerra Gir no Brasil. O animal foi hospilatizado aos 60 dias de idade, apresentando decúbito esternal permanente, apêndice cutâneo na altura da quarta vértebra lombar e cifoescoliose da coluna vertebral torácica caudal e lombossacra. Ao exame radiográfico da coluna e do crânio, foram observadas espinha bífida e suspeita de hipoplasia occipital. Ao exame de mielografia com injeção de contraste lombar e atlanto-occipital, foi possivel visualizar a meningocele na altura da quarta vértebra lombar e achados em nível rombencefálico de aumento da pressão regional com falha de preenchimento do contraste na fossa posterior, na presença de nítida demarcação das circunvoluções do córtex cerebral e do espaço subaracnoide da medula espinhal cervical. Ao exame ultrassonográfico do cerebelo, foi observada insinuação do verme cerebelar através do forame magno. O animal não apresentou alterações em hemograma completo, série bioquímica e fluido cérebro-espinhal e foi negativo para Pestivirus. Houve uma piora do quadro clínico e o animal morreu. Essa malformação de etiologia desconhecida deve ser estudada como um diagnóstico diferencial.(AU)

Resting-state functional magnetic resonance imaging of the cerebellar vermis in patients with Parkinson's disease and visuospatial disorder.

PURPOSE: Visuospatial disorders (VSDs) are common in Parkinson's disease (PD). VSDs may involve cerebellar vermis, but evidence from functional connectivity (FC) studies is lacking. Here we compared FC between cerebellar vermis and the entire brain between PD patients with or without VSD, and between patients and healthy controls. METHODS: Resting-state 3.0-T functional magnetic resonance imaging was performed on 19 controls, 31 PD patients with VSD and 12 PD patients without VSD. Correlations in brain network were calculated between eight regions of interest in the cerebellar vermis (I-VIII) and other voxels in the brain, and voxel-based FC was analyzed. Patients were assessed in terms of cognitive function as well as motor and non-motor symptoms. RESULTS: In both types of patients, cerebellar vermis VIII, IX and X showed positive FC with the default-mode network (DMN), executive control network and sensorimotor network. Cerebellar vermis I and II showed positive FC with the visual network and DMN in controls, but negative FC in PD patients without VSD. Cerebellar vermis X showed negative FC with lobules VIII and IX of the left cerebellar hemisphere in controls, but positive FC in PD patients with VSD. CONCLUSION: Positive FC connecting the cerebellar vermis VIII and X with associated brain networks in PD patients with VSD may be compensatory activation. PD may involve disruption of functional coupling between the cerebellar vermis and cerebral cortex.

Isolated Upward Rotation of the Fetal Cerebellar Vermis (Blake's Pouch Cyst) Is a Normal Variant: An Analysis of 111 Cases.

INTRODUCTION: The objective of the study was to provide more detailed data about fetal isolated upward rotation of the cerebellar vermis rotation (Blake's pouch cyst) in particular regarding pregnancy outcome. METHODS: This is a retrospective study of all cases of fetal isolated upward rotation of the cerebellar vermis (URCV) diagnosed in 3 referral centers in Italy from January 2009 to November 2019. Whenever possible, prenatal magnetic resonance imaging (MRI) was performed and a fetal karyotype was obtained. A detailed follow-up was obtained by consultation of medical records, interview with the parents, and the pediatricians. RESULTS: Our study population included 111 patients with a prenatal diagnosis of isolated URCV made at a median gestational age of 21 weeks +3 days (interquartile range (IQR) 21 + 0-22 + 2). The median brain stem-vermis (BV) angle was 27° (IQR 24-29°). In 37.9% of the cases, a regression of the finding with restoration of normal anatomy was noted at a follow-up scan or at postnatal checks. A BV angle of 25° or less predicted regression with a probability in excess of 90%. MRI was performed in utero or at birth in 101 patients and always confirmed sonographic diagnosis. Fetal CGH array and/or karyotype was available in 97 cases and was always normal, but in 1 case. A postnatal follow-up was available in 102 infants (mean 7 months, range 0-10 years of age) and documented a normal neurologic development in all the cases. CONCLUSIONS: Isolated URCV is most likely a normal variant of fetal anatomy without clinical consequences, at least at an early follow-up. A BV angle of 25° or less predicts intrauterine regression of the finding, but the outcome is good in all the cases. When a confident sonographic diagnosis is made, MRI is not mandatory. The risk of a chromosomal anomaly in these cases is probably low.

Prenatal diagnosis of rhombencephalosynapsis: neuroimaging features and severity of vermian anomaly.

OBJECTIVES: To describe the prenatal neuroimaging spectrum of rhombencephalosynapsis (RES) and criteria for its classification according to the severity of vermian anomaly. METHODS: In this multicenter retrospective study of fetuses with RES between 2002 and 2020, the medical records and brain ultrasound and magnetic resonance images were evaluated comprehensively to determine the severity of the vermian anomaly and the presence of associated brain findings. RES was classified, according to the pattern of vermian agenesis and the extent of the fusion of the hemispheres, as complete RES (complete absence of the vermis) or partial RES (further classified according to the part of the vermis that was missing and, consequently, the region of hemispheric fusion, as anterior, posterior, severe or mixed RES). Findings were compared between cases with complete and those with partial RES. RESULTS: Included in the study were 62 fetuses with a gestational age ranging between 12 and 37 weeks. Most had complete absence of the vermis (complete RES, 77.4% of cases), a 'round-shaped' cerebellum on axial views (72.6%) and a transverse cerebellar diameter (TCD) < 3rd centile (87.1%). Among the 22.6% of cases with partial RES, 6.5% were classified as severe partial, 6.5% as partial anterior, 8.1% as partial mixed and 1.6% as partial posterior. Half of these cases presented with normal or nearly normal cerebellar morphology and 28.5% had a TCD within the normal limits. Infratentorially, the fourth ventricle was abnormal in 88.7% of cases overall, and anomalies of the midbrain and pons were frequent (93.5% and 77.4%, respectively). Ventriculomegaly was observed in 80.6% of all cases, being more severe in cases with complete RES than in those with partial RES, with high rates of parenchymal and septal disruption. CONCLUSIONS: This study provides prenatal neuroimaging criteria for the diagnosis and classification of RES, and identification of related features, using ultrasound and magnetic resonance imaging. According to our findings, a diagnosis of RES should be considered in fetuses with a small TCD (severe cerebellar hypoplasia) and/or a round-shaped cerebellum on axial views, during the second or third trimester, especially when associated with ventriculomegaly. Partial RES is more common than previously thought, but presents an extreme diagnostic challenge, especially in cases with normal or nearly-normal cerebellar morphobiometric features. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

A rare mutant of OFD1 gene responsible for Joubert syndrome with significant phenotype variation.

Joubert syndrome (JBTS), a rare genetic disorder resulted from primary cilium defects or basal-body dysfunction, is characterized by agenesis of cerebellar vermis and abnormal brain stem. Both genotypes and phenotypes of JBTS are highly heterogeneous. The identification of pathogenic gene variation is essential for making a definite diagnosis on JBTS. Here, we found that hypoplasia of cerebellar vermis occurred in three male members in a Chinese family. Then, we performed whole exome sequencing to identify a novel missense mutation c.599T > C (p. L200P) in the OFD1 gene which is the candidate gene of X-linked JBTS (JBST10). The following analysis showed that the variant was absent in the 1000 Genomes, ExAC and the 200 female controls; the position 200 Leucine residue was highly conserved across species; the missense variant was predicted to be deleterious using PolyPhen-2, PROVEAN, SIFT and Mutation Taster. The OFD1 expression was heavily lower in the proband and an induced male fetus compared with a healthy male with a wild-type OFD1 gene. The in vitro expression analysis of transiently transfecting c.599T or c.599C plasmids into HEK-293T cells confirmed that the missense mutation caused OFD1 reduction at the protein level. And further the mutated OFD1 decreased the level of Gli1 protein, a read-out of Sonic hedgehog (SHH) signaling essential for development of central neural system. A known pathogenic variant c.515T > C (p. L172P) showed the similar results. All of these observations suggested that the missense mutation causes the loss function of OFD1, resulting in SHH signaling impairs and brain development abnormality. In addition, the three patients have Dandy-Walker malformation, macrogyria and tetralogy of Fallot, respectively, the latter two of which are firstly found in JBTS10 patients. In conclusion, our findings expand the context of genotype and phenotype in the JBTS10 patients.

Defining the phenotypical spectrum associated with variants in TUBB2A.

BACKGROUND: Variants in genes belonging to the tubulin superfamily account for a heterogeneous spectrum of brain malformations referred to as tubulinopathies. Variants in TUBB2A have been reported in 10 patients with a broad spectrum of brain imaging features, ranging from a normal cortex to polymicrogyria, while one patient has been reported with progressive atrophy of the cerebellar vermis. METHODS: In order to further refine the phenotypical spectrum associated with TUBB2A, clinical and imaging features of 12 patients with pathogenic TUBB2A variants, recruited via the international network of the authors, were reviewed. RESULTS: We report 12 patients with eight novel and one recurrent variants spread throughout the TUBB2A gene but encoding for amino acids clustering at the protein surface. Eleven patients (91.7%) developed seizures in early life. All patients suffered from intellectual disability, and 11 patients had severe motor developmental delay, with 4 patients (36.4 %) being non-ambulatory. The cerebral cortex was normal in five individuals and showed dysgyria of variable severity in seven patients. Associated brain malformations were less frequent in TUBB2A patients compared with other tubulinopathies. None of the patients had progressive cerebellar atrophy. CONCLUSION: The imaging phenotype associated with pathogenic variants in TUBB2A is highly variable, ranging from a normal cortex to extensive dysgyria with associated brain malformations. For recurrent variants, no clear genotype-phenotype correlations could be established, suggesting the role of additional modifiers.

Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) in a Thai Patient: The Classic Clinical Manifestations, Funduscopic Feature, and Brain Imaging Findings with a Novel Mutation in the SACS Gene.

Background: A 38-year-old woman was diagnosed autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) with a novel pathogenic variant in the SACS gene presented with gradually progressive spastic ataxia since the age of 2 years; then, she became wheelchair-bound at the age of 28 years. Phenomenology: The patient presented a combination of cerebellar dysfunctions e.g., gaze-evoked nystagmus, scanning speech, finger dysmetria, and wide-based gait, lower limb spasticity, and typical funduscopic examination which was a hypermyelinated nerve fibers radiating from the optic disc. Educational value: At present, ARSACS is recognized as a rare, worldwide, inherited movement disorder in which we should to aware of a diagnosis of this disorder in the patient who is presented with FXN gene negative early-onset spastic ataxia.

The cerebral tremor circuit in a patient with Holmes tremor.

The cerebral network associated with Holmes tremor has never been determined directly. A previous study reported a brain network that is functionally connected, in healthy individuals, to different lesions that cause Holmes tremor (lesion connectome). We report a 71-year-old man with severe left-sided tremor caused by a microbleed near the right red nucleus. Using accelerometry-fMRI, we show tremor-related activity in contralateral sensorimotor cortex and cerebellar vermis. This network was distinct from, but functionally coupled to, the Holmes lesion connectome. We propose that Holmes tremor involves three distinct cerebral mechanisms: a structural lesion, an intermediate lesion connectome, and symptom-related activity.

Genetic tests aid in counseling of fetuses with cerebellar vermis defects.

OBJECTIVE: To assess the value of chromosome microarray analysis (CMA) and whole exome sequencing (WES) in fetuses with cerebellar vermis defects (CVD). METHODS: From 2013 to 2019, we performed CMA on 43 fetuses with CVD, who were divided into cerebellar vermis hypoplasia (CVH) group and Dandy-Walker malformation (DWM) group according to morphological subtypes. Subsequently, WES was performed on 19 fetuses with normal CMA results to identify diagnostic genetic variants (DGVs). RESULTS: Chromosome aneuploidies and clinically significant copy number variants were identified in 23.3% (10/43) of fetuses, and a significantly higher positive rate was found in fetuses with multiple compared with isolated malformations (36% vs 5.6%, P = .028). STAG2 genes related to Xq25 duplication syndrome was possibly a novel candidate gene for CVD. WES detected eight DGVs in seven genes among the 19 fetuses tested. Autosomal recessive ciliopathies (4/8) caused by TMEM231, CSPP1, and CEP290 mutations, were the most frequent monogenetic diseases, followed by Opitz GBBB syndrome (2/8) caused by MID1 and SPECC1L variants. CONCLUSION: The combined use of CMA and WES has the potential to provide genetic diagnoses in 42% (18/43) of fetal CVD. WES should be offered when CMA results are normal.

Brain Structural-Functional Connectivity Relationship Underlying the Information Processing Speed.

Human cognition and behavior emerge from neuronal interactions on a brain structural architecture. The convergence (or divergence) between functional dynamics and structural connectivity (SC) and their relationship with cognition are still a pivotal question about the brain. We focused on the information processing speed (IPS), assessed by the Symbol Digit Modalities Test (SDMT), once delayed IPS underlies attention deficits in various clinical conditions. We hypothesize that the SC constrains but does not determine functional connectivity, and such a relationship is related to the cognitive performance. Blood oxygenation level-dependent and diffusion tensor images of healthy young volunteers were acquired in a 3T magnetic resonance imaging machine. Activation maps included the left and right middle frontal gyri, left superior parietal lobule, left precuneus, left inferior frontal gyrus (IFG), right cuneus, left lingual gyrus, and left declive. A network involving such regions and signal propagation from visual, through cognitive, up to motor regions was proposed. Random effects Bayesian model selection showed that the top-down connections have the highest expected and exceedance probabilities. Moreover, all pairs of task-related regions were connected by at least one tract, except for the left declive with the left IFG. The interactions between the right cuneus with left declive were related to the interindividual variability in SDMT performance. Altogether, our findings suggest that the IPS functional network is related to the highest SDMT scores when its effective endogenous connections are suppressed to the detriment of modulation caused by the experimental conditions, with the underlying structure providing low diffusion environments.

Prenatal magnetic resonance imaging within the 26th week of gestation may predict the fate of isolated upward rotation of the cerebellar vermis: insights from a multicentre study.

OBJECTIVES: We investigated whether prenatal magnetic resonance imaging (MRI) within 26 weeks of gestation (GW) may predict the fate of isolated upward rotation of the cerebellar vermis (URCV). METHODS: This retrospective multicentre observational study included foetuses diagnosed with isolated URCV in prenatal MRI performed within 26 GW. Isolated URCV was defined by a brainstem-vermis angle (BVA) ≥ 12° in the MR midline sagittal view without abnormalities of the supratentorial structures, brainstem, or cerebellum hemispheres. The assessments included the BVA, clival-supraoccipital angle, transverse diameter of the posterior cranial fossa, tentorial angle, width of the cisterna magna (WCM), ventricular width, vermian diameters, hypointense stripes, and cerebellar tail sign. Late prenatal or postnatal MRI was used as a reference standard to assess the final vermian fate (rotated/de-rotated). RESULTS: Forty-five foetuses (mean GW at prenatal MRI = 21.5 ± 1.4 weeks) were included. In the reference standard, the vermis was de-rotated in 26 cases (57.7%). At least two of the following criteria were used to predict the persistence of URCV at imaging follow-up: BVA ≥ 23°, WCM ≥ 9 mm, and the cerebellar tail sign. The results were a sensitivity of 84.21% (95% CI, 60.4-96.6%), specificity of 80.8% (95% CI, 60.6-93.4%), positive predictive value of 76% (95% CI, 58.7-87.8%), and negative predictive value of 87.5% (95% CI, 70.9-95.2%). CONCLUSIONS: MRI within 26 GW on foetuses diagnosed with isolated URCV may predict delayed cerebellar vermis de-rotation, which is associated with good neurodevelopmental outcome in most cases. KEY POINTS: • Foetal MRI is a valuable tool in predicting the fate of isolated upward-rotated cerebellar vermis. • A wider angle between the brainstem and vermis is associated with higher risk of persistence of vermian rotation. • The presence of ≥ 2 factors among a brainstem-to-vermis angle ≥ 23°, width of the cisterna magna ≥ 9 mm, and the presence of the "cerebellar tail sign" has a sensitivity of 84.21% (95% CI, 60.4-96.6%) and specificity of 80.8% (95% CI, 60.6-93.4%) in predicting the persistence of the vermian rotation at imaging follow-up.