Wednesday, 3 April 2019

Nothnagel syndrome MRI

A rare midbrain stroke syndrome that involves the tectum of the midbrain, including the quadrigeminal plate.
Classically, the syndrome involves the oculomotor nerve fascicles and superior cerebellar peduncle, leading to ipsilateral CN III palsy and limb ataxia respectively.
Although it can be caused by stroke, especially hemorrhages rather than infarctions, it is more commonly seen due to neoplasm.

Tuesday, 12 March 2019

Nasolabial cyst MRI

Nasolabial cyst also known as nasoalveolar cyst or Klestadt Cyst.
A rare non odontogenic, developmental cyst derived from epithelial cells retained in mesenchyme after fusion of medial and lateral nasal processes and the maxillary prominence during fetal development, occurring in midline at superior alveolar margin in alar region of nose.
3 times more common in females than males, most often an asymptomatic, mobile fluctuant non-tender swelling.
Often detected incidentally on CT or MRI BRAIN as isodense round nodule on CT. Signal characteristic of lesion varies on MRI ranges from hypo-to hyperintense on T1-weighted images and Hyperintense to hypointense on T2-weighted images depending upon its content, clear or thick.
Differential diagnosis is odontogenic cyst which is peri apical inflammatory lesion associated with osseous thinning of adjacent superior articular margin. 

Wednesday, 6 February 2019

Fukuyama congenital muscular dystrophy MRI

Clinically: Floppy infant / hypotonia.

MRI findings:
Bilateral frontal Polymicrogyria.
Diffuse cerebral cortical atrophy marked in bilateral frontal and temporal lobes.
Bilateral temporo occipital white matter show patchy T2 hyper intensity suggestive of associated dysmyelination, bilateral hippocampal Mal orientation, ex vacuo dilatation of temporal horns of lateral ventricles.
Associated hypoplasia of corpus callosum.
Poorly pneumatised of paranasal sinuses and mastoid air cells.
Micro crania, brachycephaly, small posterior fossa.
Brainstem atrophy, mid line cleft on ventral aspect of Pons.
No associated cerebellar dysplasia. Ill-defined mid line vermis.


Imaging diagnosis: Fukuyama congenital muscular dystrophy more likely than Walker Warburg syndrome as there is no associated cerebellar dysplasia.

Fukuyama congenital muscular dystrophy

Named after Yukio Fukuyama (1928-2014), a Japanese pediatric neurologist, who first described the condition in his 1960.

Exclusively found in Japan with an incidence of 2/4 per 100,000 infants and is the second most common muscular dystrophy after Duchenne muscular dystrophy.
Affected infants are hypotonic, generalised symmetric weakness affecting extremities and facial muscles by 1 year.
Accompanied by developmental delay and intellectual disability afterwards with epilepsy.

An autosomal recessive inherited disease due to a mutation in the fukutin-related protein (FKTN) gene.

Classic MRI brain features are polymicrogyria typically in the frontal and parietal lobes.Pachygyria in approximately half of patients, typically involving the temporal and occipital lobes.
Cerebellar polymicrogyria is seen in approximately 90% of patients. White matter changes patchy, spotty suggestive of dysmyelination.
Walker-Warburg syndrome is one of its main differentials, in which cerebellar dysplasia is commonly seen is not very common in Fukuyama congenital muscular dystrophy

Definitive treatment not available.

Monday, 4 February 2019

Crossed cerebellar diaschisis

Clinical presentation: Frequent seizures, altered sensorium. 

MRI brain shows marked left hemi Atrophy, ex vacuo dilatation of left lateral ventricle owing to volume loss. Left cerebral hemisphere show multifocal patchy areas of cortical T2 hyper intensities without diffusion restriction. Associated Atrophy of left deep grey nuclei, changes of distal Wallerian degeneration involving left cerebral peduncle of mid brain, Pons.

Imaging diagnosis: Sequel of encephalitis / rasmussen encephalitis.

Right cerebellar hemisphere show marked atrophy can attributed to associated contralateral cerebellar diaschisis. 

Crossed cerebellar diaschisis

Refers to supra tentorial lesion leading to depressed function, metabolism and perfusion of contra lateral cerebellar hemisphere which is connected via white matter tracts.
Interruption of this cortico-ponto-cerebellar white matter tracts which then results in deafferentation and hypometabolism of the contralateral cerebellar hemisphere.

Classically seen following cerebral infarction, although it can be a sequel of any significant supratentorial lesion like bleed, encephalitis as in our case. The same phenomenon can also occur in thalamus called ipsilateral thalamic diaschisis, occurring after an ipsilateral middle cerebral artery territory infarction.

CT or MRI perfusion performed during an acute stroke may show a contralateral cerebellar hypo perfusion. In chronic stages volume loss involving contralateral cerebellar hemisphere.

Clinically other than the neurological deficits associated with the contra lateral supra tentorial lesion, the condition is generally asymptomatic. No treatment apart from management of the supratentorial insult.

Sunday, 6 January 2019

Parsonage Turner Syndrome MRI

Clinically : Middle aged male with Left side severe neck and shoulder pain followed by left shoulder abduction weakness.
MRI cervical spine normal.
Neurological examination mentions rotator cuff abductor weakness and latissimus dorsi wasting. 
NCV findings positive, confirmed left side supra scapular neuropathy. 

MRI shows diffuse T2 hyper intense odema involving supra and infra spinatous muscle.
Deltoid muscle spared. No obvious para labral cyst or supra glenoid notch cyst to cause supra scapular nerve compression.
Clinically spontaneous sudden onset without history of trauma or weight lifting.

Clinical history and imaging findings are typical of Parsonage Turner Syndrome.

Parsonage Turner Syndrome 

An acute idiopathic brachial neuritis.
Male predominance,majority between 3rd to 7th decade.
Clinical presentation is typically quite sudden painful shoulder girdle followed by progressive weakness.
Symptoms non-specific and can mimic numerous other much more common conditions.
Condition is unilateral in two-thirds of cases.
A combination of history, EMG with suprascapular neuropathy and imaging findings makes the diagnosis.
The etiology is uncertain, although viral infection or immunological cause is suspected.
In almost all cases (97%) the suprascapular nerve is involved and muscles are supraspinatus and infraspinatus (innervated by suprascapular nerve.
The most striking features on MRI are denervation changes in muscles with diffuse high T2 signal. Gradually atrophy and fatty infiltration on follow up imaging or chronic cases.
Typically self-limiting and requires supportive therapy. 90% will have excellent recovery by three years.