School ager hit in left eye by a baseball

CT of orbital blowout fracture — Coronal CT without contrast of the orbits (right) shows a discontinuity in the floor of the left orbit, with soft tissue herniated through the discontinuity into the left maxillary sinus.

The diagnosis was orbital blowout fracture.

Newborn with a sacral dimple

US of filar cyst — Sagittal US of the spine (above) shows the conus medullaris to terminate normally at the L1-L2 level. A hypoechoic cystic structure is seen just inferior to the conus and is better seen on the zoomed image (below).

The diagnosis was filar cyst.

Toddler refusing to walk

MRI of posterior fossa ependymoma — Sagittal T1 MRI without contrast of the brain (left) shows an isointense mass filling and distending the fourth ventricle and exiting it and extending beneath the foramen magnum into the spinal canal. The axial T2 MRI (right) shows the hyperintense mass surrounding the left side of the cervical spinal cord.

The diagnosis was ependymoma.

Teenager with left sided weakness after a wrestling injury

MRA of internal carotid artery dissection — 3D reconstruction from a MRA with contrast of the neck and brain shows tapering of the luminal diameter and decreased flow in the right internal carotid artery beginning at its horizontal segment until its terminus. The right middle carotid artery M1 and M2 segments are not visualized.

The diagnosis was distal right internal carotid artery dissection.

Preschooler with decreased hearing on the right

CT of cholesteatoma — Axial CT without contrast of the temporal bones shows an abnormal soft tissue density in the right middle ear.

The diagnosis was cholesteatoma.

Infant of a diabetic mother

AXR and CT of caudal regression syndrome — AXR (above) and axial CT without contrast of the pelvis (below) shows hypoplasia of the lower lumbar spine and complete absence of the sacrum with approximation of the iliac wings in the midline.

The diagnosis was caudal regression syndrome.

Infant with brachial plexus injury at birth

MRI of avulsion pseudomeningocele — Sagittal (left) and axial (right) T2 MRI without contrast of the cervical spine shows a left sided extradural CSF collection posterior to the spinal cord from C6 to T1.

The diagnosis was avulsion pseudomeningocele with possible avulsion of the C7 nerve root.

School ager with obstructive sleep apnea

MRI of antrochoanal polyp — Axial (left), coronal (middle), and sagittal T1 MRI with contrast of the paranasal sinuses show a left-sided polyp extending from the left maxillary sinus (center), to the nasal cavity (left), to the nasopharynx and ultimately to the oropharynx and abutting the epiglottis (right).

The diagnosis was antrochoanal polyp.

Teenager with neck pain and nausea

MRI of acute disseminated encephalomyelitis / ADEM — Axial FLAIR MRI of the brain (upper and lower left) show multiple high signal intensity lesions primarily in the white matter as well as in the medulla that enhance on T1 MRI with contrast (upper right). Sagittal T2 MRI without contrast of the cervical spine (below right) shows high signal intensity expansile lesions in the spinal cord from C2 to C7 as well as from T2 to T3.

The diagnosis was acute disseminated encephalomyelitis.

Infant with bilious vomiting

Surgical image of malrotation with midgut volvulus — Surgical image shows spiraling of the bowel around the midgut mesentery (right superiorly). The small bowel (peripherally) is dusky in color.

The diagnosis was malrotation with midgut volvulus.

Pediatric Imaging Pearl of the Week

View the illustrated DDX of intracranial infection.

Infant with sepsis

MRI of Group B streptococcus meningitis and cerebritis — Axial (left) and coronal (right) T1 MRI with contrast of the brain show diffuse meningeal enhancement along with a large variably enhancing solid right occipital lesion that has surrounding edema.

The diagnosis was meningitis and cerebritis due to Group B streptococcus.

Former premature newborn, now 1 month old with seizures

Head US of E. coli meningitis — Coronal US of the brain (above) shows a dilated ventricular system that contains complex echogenic fluid. Axial CT without contrast of the brain (below) shows a dilated ventricular system that contains complex fluid.

The diagnosis was meningitis due to E. coli resulting in pus in the ventricular system causing communicating hydrocephalus.

Teenager with fever and mental status changes

CT of intraventricular intracranial abscess — Axial CT with contrast of the brain shows ring enhancing lesions in the anterior horn of the left lateral ventricle and faint enhancement of the ependymal lining of the ventricles. There is hydrocephalus present as well as effacement of the basilar cisterns.

The diagnosis was intraventricular intracranial abscess causing communicating hydrocephalus. When a ventriculostomy catheter was placed, pus shot out of it.

Teenager with a seizure

CT of toxoplasmosis encephalitis — Axial CT without contrast of the brain shows bilateral cortical and periventricular coarse calcifications.

The diagnosis was toxoplasmosis encephalitis.

Newborn with a full fontanelle

US of HSV-1 / herpes simplex virus-1 encephaliti — Coronal US of the brain (above) shows a round echogenic lesion in the left fronto-parietal region. Axial CT without contrast of the brain (below) shows the lesion to be high density with surrounding low density edema and felt to represent intraparenchymal hemorrhage.

The diagnosis was herpes simplex virus-1 encephalitis.

Toddler with seizures

MRI of CMV / cytomegalovirus encephalitis — Axial T1 MRI without contrast of the brain (left) shows gyral thickening compatible with pachygyria and ventriculomegaly. Axial T2 MRI (right) shows increased bright signal throughout the white matter, compatible with delayed myelination. There are also several areas of punctate low signal along the periphery of the lateral ventricles posteriorly, compatible with foci of calcification, which were confirmed on GRE images (not provided).

The diagnosis was cytomegalovirus encephalitis, which most likely occurred in the first trimester.

School ager with headache and lethargy with a recent travel history in Africa

MRI of cysticercosis — Axial T2 (above left), FLAIR (above right), T1 (below left) and T1 MRI with contrast (below right) of the brain show a small round lesion in the left frontoparietal region at the grey matter-white matter junction with a large amount of surrounding edema that enhances peripherally.

The diagnosis was cysticercosis.

Teenager who is immune suppressed with headaches

MRI of cryptococcosis — Axial FLAIR (above) MRI without contrast of the brain shows a small round lesion in the left frontal lobe with surrounding edema that demonstrates ring-shaped restricted diffusion on diffusion-weighted imaging (below).

The diagnosis was cryptococcosis.

Our DDX For This Week Is

View the illustrated DDX of intracranial infection

Infant with bilious vomiting

Surgical image of malrotation with midgut volvulus — Surgical image shows spiraling of the bowel around the midgut mesentery in the center of the image. The small bowel (inferiorly) is dusky in color.

The diagnosis was malrotation with midgut volvulus.

Pediatric Imaging Pearl of the Week

View the illustrated DDX of spinal dysraphism.

Preschooler who had their myelomeningocele extending from L4-S5 repaired in utero

3D CT of myelomeningocele — 3D reconstruction of CT without contrast of the lumbar spine shows lack of fusion of the posterior elements of the L4-S5 vertebral bodies.

The diagnosis was myelomeningocele.

Newborn with an occipital protuberance

MRI of cervical meningocele — Axial (above left) and sagittal (below left) T1 and axial (above right) and sagittal (below right) T2 MRI without contrast of the cervical spine show a midline occipital mass which is not covered with subcutaneous fat that contains fluid centrally and which communicates via a thin tract to a protruding CSF space just below and contiguous to the cisterna magna through a discontinuity in the subcutaneous fat.

The diagnosis was a cervical meningocele.

Newborn with a skin covered bump on the back

MRI of lipomyelomeningocele — Sagittal T1 (left), T2 (middle) and T1 with contrast (right) MRI of the lumbar spine show a low-lying conus medullaris at the level of S2, which ends in a lipomatous mass that via a defect in the bone is contiguous with the subcutaneous fat posteriorly.

The diagnosis was lipomyelomeningocele.