Asymmetric Meckel Cave Enlargement: A Potential Marker of PHACES Syndrome

Not Dandy Walker variant: a review of prominent retrocerebellar CSF space in children

The prominent retrocerebellar cerebrospinal fluid (CSF) space can be frequently encountered on paediatric neuroimaging studies. In cases involving abnormal vermian development where imaging does not align with the established criteria of Dandy-Walker malformation (DWM), the term "Dandy-Walker variant or continuum" has been historically employed to describe the aberrant posterior fossa development. Instead, the emphasis is on a more elaborate description of the findings in the posterior fossa. Moreover, combining the findings in the supratentorial brain can occasionally predict certain neurogenetic disorders that mimic Dandy-Walker phenotype. The present review demonstrates and differentiates the imaging features of various entities that result in an enlarged retrocerebellar CSF space, such as inferior vermian hypoplasia (IVH) and several neurogenetic conditions.

Flatness of the Meckel cave may cause primary trigeminal neuralgia: a radiomics-based study

Background

Neurovascular contact (NVC) is the main cause of primary trigeminal neuralgia (PTN); however, cases of PTN without NVC are still observed. In this study, the Meckel cave (MC) morphology in PTN were analyzed by radiomics and compared to healthy controls (HCs) to explore the cause of PTN.

Methods

We studied the 3.0T MRI data of 115 patients with PTN and 46 HCs. Bilateral MC was modeled using the 3D Slicer software, and the morphological characteristics of MC were analyzed using the radiomics method.

Results

The right side incidence rate in the PTN group was higher than the left side incidence. By analyzing the flatness feature of MC, we observed that the affected side of the PTN was lower than that of the unaffected side, the right MC of the PTN and HC was lower than that of the left MC, the MC of the affected side of the left and right PTN without bilateral NVC was lower than that of the unaffected side.

Conclusions

By providing a method to analyze the morphology of the MC, we found that there is an asymmetry in the morphology of bilateral MC in the PTN and HC groups. It can be inferred that the flatness of the MC may be a cause of PTN.

Neuroaxial Infantile Hemangiomas: Imaging Manifestations and Association with Hemangioma Syndromes

BACKGROUND AND PURPOSE

Infantile hemangiomas are common lesions in the pediatric population; in rare cases, an infantile hemangioma can be detected along the neural axis. The purposes of our study included determination of the incidence, location, and imaging appearance of neuroaxial infantile hemangiomas and their syndromic association. We also assessed additional features of cerebral and cardiovascular anomalies that may be associated with neuroaxial lesions.

MATERIALS AND METHODS

A retrospective cohort study was performed, searching the radiology database for patients with segmental infantile hemangiomas referred for assessment of possible hemangioma syndromes. We retrospectively reviewed brain and spine MR imaging studies, with particular attention paid to neuroaxial vascular lesions, as well as the relevant clinical data. Neuroaxial hemangioma imaging findings were described, and comparison of segmental cutaneous infantile hemangioma location with the imaging findings was performed in patients with confirmed hemangioma syndromes and in patients with isolated skin infantile hemangioma.

RESULTS

Ninety-five patients with segmental infantile hemangioma were included in the study, 42 of whom had a hemangioma syndrome; of those, 41 had posterior fossa brain malformations, hemangioma, arterial lesions, cardiac abnormalities, and eye abnormalities (PHACE) syndrome and 1 had diffuse neonatal hemangiomatosis. Neuroaxial involvement was detected in 20/42 patients (48%) with hemangioma syndromes and in no subjects with isolated segmental infantile hemangioma (P < .001). The most common intracranial hemangioma location was within the ipsilateral internal auditory canal (83%).

CONCLUSIONS

Many pediatric patients with segmental infantile hemangioma in the setting of hemangioma syndromes, especially those with PHACE, had neuroaxial hemangiomas. This finding may potentially lead to requiring additional clinical evaluation and management of these patients.

Arterial Spin-Labeling Perfusion for PHACE Syndrome

BACKGROUND AND PURPOSE

Arterial stroke is a rare-but-reported complication in patients with posterior fossa brain malformations, hemangiomas, arterial anomalies, coarctation of the aorta and cardiac defects, and eye abnormalities (PHACE) syndrome. Currently, stroke risk is inferred by the severity of arterial anomalies identified on MRA, though no evidenced-based data exist. The purpose of our study was to determine whether arterial spin-labeling MR imaging perfusion can detect alterations in CBF in patients with PHACE syndrome.

MATERIALS AND METHODS

Records were reviewed from 3 institutions for all patients with PHACE syndrome who underwent arterial spin-labeling from 2000 to 2019. CBF was qualitatively investigated with arterial spin-labeling to determine whether there was decreased or normal perfusion. Arterial anomalies were characterized on MRA imaging, and parenchymal brain findings were evaluated on conventional MR imaging sequences.

RESULTS

Forty-one patients with PHACE syndrome had arterial spin-labeling imaging. There were 30 females and 11 males (age range, 7 days to 15 years). Of the 41 patients, 10 (24%) had decreased CBF signal corresponding to a major arterial territory. Ten of 10 patients had decreased CBF signal in the anterior circulation, 2/10 had decreased anterior and posterior circulation CBF signal, 2/10 had decreased bilateral anterior circulation CBF signal, and 1/10 had globally decreased CBF signal. Forty of 41 (97.5%) patients had at least 1 arteriopathy, and in those with decreased CBF signal, the arteriopathy corresponded to the CBF signal alteration in 10/10 patients.

CONCLUSIONS

Arterial spin-labeling can potentially characterize hemodynamic changes in patients with PHACE syndrome.

The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features

Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.

Hearing loss in PHACE syndrome: clinical and radiologic findings

PURPOSE

To characterize the types of hearing loss, auditory-related imaging findings, and hemangioma characteristics in patients with Posterior fossa malformations, Hemangiomas, Arterial anomalies, Cardiac defects, and abnormalities of the Eye (PHACE) syndrome.

METHODS

Retrospective medical records, audiologic data, and imaging review of all patients presenting to a tertiary care children's hospital with a proven diagnosis of PHACE syndrome from 2005 to 2016.

RESULTS

Twelve patients were identified with hearing and imaging data. 5/12 had hearing loss, 1 had unilateral severe sensorineural loss with minor conductive component, 1 had unilateral moderate sensorineural loss with minor conductive component, 1 had mild bilateral conductive loss, 1 had bilateral hearing loss (left severe mixed and right severe sensorineural), and 1 had moderate bilateral conductive loss. All patients passed their newborn hearing screening. Of the 5 patients with hearing loss, 3 had IAC hemangiomas (1 bilateral), 3 had enlarged IACs with prominent posterior petrous bones (1 bilateral), 2 had dysgenesis of the cerebellar vermis and hemispheres, there was 1 patient each with a deformed pinna and middle ear and mastoid effusions, and 1 patient had no abnormal auditory-related imaging findings. Patients with hearing loss were more likely to have more areas of cutaneous hemangioma involvement (mean 6.4 vs 3.1, p = .05). Laterality of hearing impairment correlated with the side of cutaneous hemangioma in all patients with hearing loss. Treatment with systemic propranolol did not improve hearing.

CONCLUSIONS

Patients with PHACE are at risk for hearing loss and may demonstrate radiologic abnormalities within the ear structures, although the type of hearing loss, imaging findings, and their respective correlation vary. While our results are limited by our small sample size, comprehensive audiology evaluations (as opposed to newborn screening testing only) should be considered for PHACE patients who have extensive cutaneous hemangioma or auditory-related imaging abnormalities, such as internal auditory canal hemangiomas.