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.

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.

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.

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.

School ager with skin stigmata along the spine

CT of diastematomyelia
AP radiograph of the spine (left) suggests a linear piece of bone in the center of the spinal canal at the L2-L3 level. Axial CT without contrast of the spine at the L2-L3 level (right) shows the spinal cord and thecal sac are bisected by a boney bridge in the center of the spinal canal. There is also evidence of vertical fusion of the spinal lamina.

The diagnosis was diastematomyelia.

Toddler with left arm weakness

CT and MRI of supratentorial primitive neuroectodermal tumor
Axial CT without contrast of the brain (above left) shows an ill-defined large heterogenous right periventricular mass causing midline shift to the left. Axial T2 (above right) and T1 MRI without contrast (below left) of the brain show the mass to be fairly well circumscribed, primarily solid with some cystic components, and to show heterogenous enhancement on axial T1 MRI with contrast (below right).

The diagnosis was primitive neuroectodermal tumor.