Neuroradiologic findings in pontine and extrapontine myelinolysis

Contrast enhancement on MRI in the early phase of central pontine myelinolysis
Three days after symptom onset, T2-weighted MRI showed a hyperintense lesion of the pons (A) and of the basal ganglia (B). Coronal postgadolinium T1-weighted MRI showed a nonhomogeneous enhancement of the pontine lesion 3 days after symptom onset (C), which diminished 15 days later (D).

Sequential MRI of the pituitary in Sheehan syndrome

Coronal and sagittal postcontrast T1-weighted spin-echo images show an enlarged pituitary with rim enhancement and no internal enhancement (arrows). Findings are suggestive of nonhemorrhagic pituitary infarct, i.e., Sheehan syndrome.  
Temporal evolution of the pituitary gland in Sheehan syndrome
Coronal and sagittal postcontrast T1-weighted spin-echo images show atrophy of the anterior pituitary gland (arrows) on follow-up MRI 1 year later.

Lipoma of trigeminal nerve in a patient with severe trigeminal neuralgia

T1 coronal images show homogenous hyperintense lesion involving the right trigeminal nerve root (white arrows) in A and B and Meckel's cave (white arrow) in C as compared to normal left trigeminal nerve (black arrows) and Meckel's cave (yellow arrow). Axial T1 image also demonstrates the involvement of mandibular division in foramen ovale (white arrow) as compared to normal on left side (orange arrow) in D.

A case of partial oculomotor palsy

Examination of conjugate extraocular movements showing right adduction palsy and right partial ptosis

(A) Brain MRI shows hyperintense signal in the dorsal midbrain on the right side on axial T2-weighted image and (B) schematic representation of the oculomotor nerve fascicles in the midbrain with the arrangement of various fibers in the oculomotor nerve fascicle: IO = inferior oblique; IR = inferior rectus; LPS = levator palpebrae superioris; MR = medial rectus; PF = pupillary fibers; SR = superior rectus. (C, D) Diffusion-weighted imaging (coronal) with reduced apparent diffusion coefficient on the corresponding site.

A slowly growing benign brain mass

(A–H) T2-weighted images (repetition time msec/echo time msec, 2,150/30; 3-mm-thick sections; matrix, 256 × 256; field of view 250 mm2) show a neuroglial cyst in the right hemisphere measuring 16 cm3 initially and increasing to 175 cm3 with considerable mass effect after 7 years.

Bilateral anterior thalami and fornix macrohemorrhage in Wernicke-Korsakoff syndrome

Sagittal T1-weighted MRI (A) shows hemorrhage involving the anterior thalamus just beneath the fornix. Axial T2*-weighted MRI (B) shows bilateral fornix hemorrhage with asymmetrical bithalamic involvement.

Acute necrotizing encephalopathy during novel influenza A (H1N1) virus infection

MRI: Axial (A) and sagittal (B) T2-weighted MRI shows confluent hyperintensity involving the cortical–subcortical regions of the occipital and parietal lobes. There are also several small areas in internal and external capsula, insular cortex, and bilaterally in the thalamus and in the left superior cerebral peduncle (A, B). Axial diffusion-weighted image map shows restricted water diffusion in the corresponding areas mimicking acute ischemic infarction with cytotoxic edema. The lesions are not confined to a certain arterial territory (C). The spectroscopic study (echo time = 144 msec) shows high peaks for lactate (arrow), with normal values for choline, creatine, and NAA (D).

Isolated vertigo and imbalance due to deep border zone cerebellar infarct

Right deep border zone cerebellar infarct with ipsilateral proximal large artery disease
Axial (A) diffusion-weighted imaging displays acute deep infarct at the boundary zone between medial and lateral branch of the right posterior inferior cerebellar artery. Anterior (B) and lateral (C) views of CT angiography show occlusion of right vertebral artery and stenosis of right subclavian artery (arrows).

Apathetic variant of frontotemporal dementia

Structural-functional correlates of apathetic variant frontotemporal dementia
(A–C) Sulcal prominence and atrophy were identified on axial T1-weighted MRI, particularly in dorsolateral and dorsomedial prefrontal regions. Mild periventricular/subcortical nonspecific white matter changes were also noted. (D–F) Fluorodeoxyglucose PET imaging revealed prefrontal (including dorsolateral, anterior cingulate, and ventromedial cortices), insular, and anterior temporal pole hypometabolism.

Perineural spread of basal cell carcinoma along the trigeminal nerve

Axial image
Postgadolinium axial T1 fat-saturated image shows a thickened maxillary nerve (thin arrow) curving toward the pterygopalatine fossa. There is also linear enhancement along the vidian nerve (dashed arrow) and the mandibular nerve (thick arrow) within foramen ovale.

Recurrent vertebrobasilar embolism out of a blind sack

Stump embolism as a cause of vertebrobasilar stroke
Digital subtraction angiography shows an ascending cervical artery with collateral refilling of the distal vertebral artery (VA). The arrow indicates the blind sack of the proximally occluded VA with a resident embolus, the presumed source of the recurrent ischemia.

Granulomatous angiitis of the CNS associated with Hodgkin lymphoma

Radiologic and histopathologic findings of the CNS lesions
(A, B) Axial and coronal postgadolinium T1-weighted imaging demonstrates extensive hemispheric and focal cerebellar abnormalities with a perivascular pattern of enhancement; (C) MRI perfusion imaging demonstrates decreased cerebral blood flow in the white matter; (D) hematoxylin & eosin section demonstrates necrotizing granulomatous angiitis.

Cochleitis

(A, B) Inner ear MRI: 2 contiguous adjacent axial enhanced fat-suppressed T1-weighted high-resolution images, showing asymmetric abnormal contrast enhancement of the right cochlea (arrows) and labyrinthine structures. Left cochlea has no detectable abnormalities, and shows no abnormal contrast enhancement (arrowheads).

Platybasia and basilar invagination in osteogenesis imperfecta

MRI of the cranio-cervical junction
(A) Narrowing of upper cervical canal (white arrow) and myelomalacia at C2 (black arrow). (B) Tip of the odontoid and anterior arch of atlas are well above Chamberlain line (white line) and the clivus canal angle is <150° (yellow line).

Neuroferritinopathy

(A) Cavitation of the basal ganglia on axial CT scan of the brain. (B) Axial susceptibility-weighted MRI shows iron deposition in basal ganglia.

MTA Atrophy 0-4

 
Visual assessment of the medial temporal lobe atrophy was performed on a single MR-slice posterior to the amygdala and the mamillary bodies.
The was positioned so the hippocampus, the pons and the cerebral peduncles were all visible. The visual assessment included hippocampus proper, dentate gyrus, subiculum, parahippocampal gyrus, entorhinal cortex and surrounding CSF spaces such as temporal horn and choroid fissure. The right and left side were rated separately. Scores range from 0 (no atrophy) to 4 (end stage atrophy).

Progressive asymmetric parkinsonism and tendon xanthomas

Clinical and radiologic signs
(A) Bilateral tendon xanthomas (arrows). (B) I-123-Ioflupane (I-123 FP-CIT) SPECT: reduced bilateral, asymmetric putaminal uptake (arrowheads). MRI (arrows): diffuse volume loss with signal abnormality, (C) in the globus pallidus, internal capsules on axial fluid-attenuated inversion recovery, (D) cerebral peduncles, substantia nigra, and (E) extensive white matter involvement of the cerebellar hemispheres including dentate nuclei on axial T2-weighted imaging.

Hemangioma of the cavernous sinus in a child

Axial T1-weighted (A) and coronal T2-weighted (B) images show an expansile 3.5 × 2.6 cm tumor in the right cavernous sinus with T1 hypointense and marked T2 hyperintense signal. Coronal (C) and axial (D) contrast T1-weighted images acquired several minutes apart reveal characteristic early heterogeneous and late homogeneous enhancement.

Dynamic Temporal Change of Cerebral Microbleeds: Long-Term Follow-Up MRI Study

Dynamic changes of MBs over a long-term MRI follow-up.
Some new MBs appeared (A), and some MBs disappeared in the follow-up MRI (B). Black arrows represent the MRI follow-up, while white arrow heads indicate new MBs, and dotted circles identify the location of those MBs which had disappeared.

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Lymphomatoid granulomatosis involving lung and brain in an immunocompetent woman

Axial T2 and enhanced T1 MRI demonstrating cerebellar T2 hyperintensity and stippled enhancement; FDG-PET avid lung lesion (arrow)
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Rhomboencephalitis due to cocaine-induced bony erosion of skull base

Sagittal T2 (A), axial T2 fluid-attenuated inversion recovery (B), and sagittal T1 with contrast MRI (C) show a large bony defect in the skull base with erosion of the sphenoid sinus walls and perforated nasal septum. There is abnormal T2 hyperintensity and enhancement in the brainstem with clival erosion (arrow where most severe) and marrow enhancement.
Axial T2 fluid-attenuated inversion recovery MRI of the brain demonstrates decreased T2 fluid-attenuated inversion recovery hyperintensity in the medulla following 6 weeks of IV antibiotics.

Anterior horn cell hyperintensity in Hirayama disease

(A) Abnormal kyphotic (straight) curvature of the cervical spine evidenced by dorsal aspects of the C3 through C6 vertebral bodies meeting a straight line (white) drawn from the dorsocaudal aspect of the C2 vertebral body to the dorsocaudal aspect of the vertebral body of C7. In addition, note the linear T2 intramedullary hyperintensity, representing atrophy and gliosis of the anterior horn cells (large arrow). (B) Transverse T2-weighted image demonstrating the owl eyes sign (hyperintensities in the anterior horns of gray matter), representing atrophy and gliosis of the anterior horn cells (white arrows)