Paediatric brainstem: A comprehensive review of pathologies on MR imaging

Abstract

The brainstem is a midline structure formed by the midbrain, pons and medulla and is a home for various vital neurological centres of the human body. A diverse spectrum of disease entities can involve the brainstem, which includes infections, metabolic disorders, demyelination, vascular conditions, neurodegenerative disorders and tumours. Brainstem involvement can be primary or secondary, i.e., as part of systemic disorders. Due to the overlapping clinical presentation and symptomatology, imaging plays a decisive role in the detection, localisation and characterisation of brainstem pathologies. Magnetic resonance imaging (MRI) is the modality of choice and the use of advanced MR techniques such as diffusion-weighted imaging and spectroscopy can be especially helpful in providing a tenable diagnoses. This article is a compilation of the MR imaging manifestations of a spectrum of common and uncommon brainstem pathologies that can be encountered in the paediatric age group. Teaching Points • The paediatric brainstem can be afflicted by many pathologies that may overlap clinico-radiologically. • MRI is the best modality for the localisation and diagnosis of brainstem pathologies. • Diffusion-weighted imaging is useful in the diagnosis of vascular and metabolic disorders. • Occasionally, demyelination and neoplasms can be indistinguishable on imaging.

Keywords: Brainstem; Demyelination; Encephalitis; Glioma; MRI.

Fig. 1

An 8-year-old patient with known acute leukaemia on induction therapy presented with bradycardia and hypotension: a–b Axial T2- and diffusion-weighted images reveal focal hyperintensity (arrow) showing diffusion restriction consistent with an acute infarct

Fig. 2

Neonate on the 5th day of life with a history of obstructed labour resulting in severe hypoxia: a–b Diffusion-weighted image shows hyperintense signal involving the pons (arrow) with corresponding signal changes on ADC. c Extensive diffusion restriction is also seen in the cerebral white matter (asterisk) consistent with severe hypoxia

Fig. 3

Neonate with a history of delayed cry: a T1-weighted image shows symmetric increased signal intensity involving the putamina (arrow) and ventrolateral thalami (dotted arrow). b–c Similar high signal intensity is also noted involving the midbrain (asterisk)

Fig. 4

A 16-year-old patient known to have Behçet disease: a Axial T2-weighted image shows increased signal intensity in the pons (arrow). b Mild post-contrast enhancement is noted in the involved region (arrow)

Fig. 5

A 16-year-old patient with acute onset headache: a Susceptibility-weighted image shows prominent blooming in the pons (arrow). b T1-weighted images show heterogeneous areas of mixed hyper- and hypointensity consistent with blood degradation products giving a “popcorn appearance.” c Heterogeneous lesion with a prominent haemosiderin rim (dotted arrow) in keeping with cavernoma. There is an associated subacute haemorrhage in the superior aspect of the lesion

Fig. 6

A 15-year-old patient with headache and incidental finding: Susceptibility-weighted image shows “caput medusa” appearance at the pontomedullary junction consistent with a capillary telangiectasia

Fig. 7

A 12-year-old boy with fever and seizures: a–c Axial T2-weighted images show hyperintense signal involving the periventricular white matter, medial thalamus and left middle cerebral peduncle suggestive of demyelination

Fig. 8

Isolated brainstem ADEM in a 12-year-old patient: a–c Axial T1-weighted image is unremarkable with hyperintense signal on T2 (arrows) involving the pons, which shows avid post-contrast enhancement. d Post treatment: Axial T2-weighted image shows near total resolution of changes in the pons

Fig. 9

A 14-year-old patient with weakness of the limbs and dysarthria: a–b Axial T2-weighted images show ill-defined increased signal intensity in the pons and midbrain (arrows). c Axial FLAIR image shows periventricular white matter hyperintensity. d Sagittal FLAIR image shows increased signal in the callososeptal interface (black arrows) consistent with multiple sclerosis

Fig. 10

A 16-year-old female with neuromyelitis optica: a–b Axial T2-weighted images show hyperintense signal involving the tegmentum (dotted arrow), periaqueductal region (arrow) of the midbrain and pons in a diffuse pattern

Fig. 11

A 15-year-old female with electrolyte imbalance and altered sensorium: a–b Axial FLAIR and T2-weighted images show increased signal in central pons (asterisk) with characteristic sparing of the periphery. c No significant post-contrast enhancement is seen

Fig. 12

A 9-month-old child with delayed milestones and seizures: a–c Axial T2-weighted images show hyperintense signal involving the putamina (dotted arrow) and medial thalamic nucleus. Caudally there is involvement of the mid brain (short arrow) with characteristic involvement of the periaqueductal region in this patient with Leigh syndrome

Fig. 13

Neonate with poor feeding, lethargy and ketoacidosis: a–c Axial diffusion weighted images show restricted diffusion involving the midbrain (arrow), pons and cerebellar white matter (dotted arrow) consistent with MSUD

Fig. 14

A 9-year-old patient known to have Wilson’s disease: a Axial T2-weighted image shows symmetrical atrophy of the basal ganglia with hyperintense signal involving the basal ganglia and thalamus (arrows). b–c Axial T2-weighted image shows increased signal intensity involving the midbrain as well as the pontine tegmentum (dotted arrows)

Fig. 15

A 6-year-old patient with haemolytic uraemic syndrome and encephalopathy: a–b Axial T2-weighted images reveal increased signal in the basal ganglia, posterior limb of internal capsules (arrow) and midbrain (dotted arrow)

Fig. 16

A 12-year-old patient with chronic renal failure and seizures: a–c Axial T2-weighted images reveal increased signal intensity in the right parieto-occipital cortex (arrow) with similar signal intensity at the cervicomedullary junction (dotted black arrow)

Fig. 17

A 3-year-old patient with cerebral palsy and delayed milestones: Axial T2-weighted image reveals focal tegmental hyperintensities at the level of medulla (arrows)

Fig. 18

An 8-month-old child with glutaric aciduria presenting with altered sensorium: Axial T2-weighted image shows hyperintensity involving the globus pallidi (arrow) and bilateral subdural hygromas (asterisk). Prominence of the CSF spaces is noted anterior to the temporal lobe. Increased signal intensity is noted in the pontine tegmentum (dotted arrow)

Fig. 19

A 5-year-old patient with a history of dog bite and comatose state during imaging: a–d Axial T2-weighted images reveal increased signal intensity in the basal ganglia (white arrow) with increased signal intensity involving the medial thalami, hippocampi (black arrow), midbrain, pons and medulla

Fig. 20

A 10-year-old patient with fever and altered sensorium: a–c Axial T2-weighted images show near symmetrical increased signal intensity in the medial thalami (white arrow), middle cerebral peduncles (black arrow) and pons (asterisk). The possibility of viral encephalitis, likely Japanese encephalitis, was considered. d–e Follow-up MRI: Axial T2-weighted images show hypointense foci (possibly remote haemorrhage) in the thalami with volume loss and an area of gliosis in the pons

Fig. 21

A 6-year-old patient with fever and headache: a–b Axial contrast enhanced T1 image shows marked meningeal enhancement in basal cisterns (arrow), middle cerebral artery cisterns (dotted arrows) and dilated lateral ventricles (thin arrows arrow) in a case of tubercular meningitis

Fig. 22

6 year old with headache, vomiting and fever: a Axial FLAIR image reveals hyperintense signal involving the medulla with extension into the adjacent cerebellar white matter. b and c Coronal T2-weighted image reveals small lesion with peripheral hypointensity at pontomedullary junction (arrow), the lesion shows peripheral enhancement on post contrast images. Possibility of CNS tuberculoma was considered. d–e Follow-up after 3 months on anti-tubercular treatment: Axial FLAIR and T2-weighted images show significant reduction in the hyperintensity involving the medulla with residual lesions. Clinically the child showed significant improvement

Fig. 23

A 16-year-old patient with acute promyelocytic leukaemia on chemotherapy with angioinvasive aspergillosis: a–b Axial T2- weighted MRI shows increased signal intensity in the temporal lobes (white arrow) with involvement of the cerebral peduncles. Similar signal intensity is noted in the frontal white matter bilaterally. c–d Significant blooming (dotted arrows) is noted on susceptibility-weighted imaging

Fig. 24

A 13-year-old patient with cerebral malaria: Axial T2-weighted MRI reveals hyperintense foci showing diffusion restriction in the left cerebellum, pons, bilateral basal ganglia and corpus callosum (arrows) corresponding to areas of cytotoxic oedema

Fig. 25

A 9-year-old child with headache and vomiting: a Sagittal T1-weighted image shows expansion of the pons with hypointense signal (asterisk). b Axial T2-weighted image shows increased signal intensity involving the pons (asterisk) with the basilar artery (arrow) appearing engulfed by the lesion. Posteriorly the fourth ventricle is compressed (dotted arrow) (flat fourth ventricle sign). c No significant contrast enhancement is noted within the lesion

Fig. 26

A 16-year-old male with headache and vomiting: a–b Axial FLAIR and T2-weighted sagittal MRI shows a relatively well-defined hyperintense lesion involving the tectum (arrow). The aqueduct is encased and compressed (dotted arrow) with resultant dilatation of the temporal horns (block arrow). c No significant contrast enhancement is noted in keeping with a glioma

Fig. 27

A 15-year-old male with altered headache and lower cranial nerve palsies: a–b Axial and sagittal T2-weighted image reveals an ill-defined hyperintense expansive lesion involving the medulla (*), which is extending caudally to involve the cervical cord (arrow). c Post contrast the lesion shows homogeneous enhancement (dotted arrows)

Fig. 28

A known case of neurofibromatosis type I with hydrocephalus: a–b Axial T2-weighted images show mild expansion of the midbrain and pons with multiple hyperintense lesions involving the midbrain, pons and cerebellar peduncle (arrow). Periaqueductal hyperintensity with narrowing of the aqueduct (black arrow) resulting in third ventricular dilatation (dotted arrow)

Fig. 29

A 5-year-old patient with cerebellar medulloblastoma: a–b Axial T2-weighted and diffusion-weighted image shows a large hypointense mass showing restriction in the left cerebellar hemisphere causing severe brainstem compression

Fig. 30

A 17-year-old patient with acute myeloid leukaemia: a–b Axial T2 and post-contrast T1-weighted image shows an enhancing mass in the left masticator space suggestive of a chloroma (asterisk). c Axial T1-weighted image shows enhancing deposits in the left cerebellum (dotted arrow) and pons (arrow)