Sunday 18 August 2019

Sickle Cell Anemia MRI

Multiple vertebrae show subchondral collapse in dorso lumbar region.
Hip screening show avascular necrosis involving bilateral capital femoral epiphysis..
Ill-defined heterogeneous marrow oedema involving Acetabular fossa, Femoral head neck on either side, mild joint effusion.

Suggested detailed haematological / bone marrow evaluation.
On further evaluation, turned out to be a case of sickle cell anaemia.

Sickle cell disease

A hereditary autosomal recessive condition resulting in the formation of abnormal hemoglobin which manifests as multisystem ischemia and infarction as well as hemolytic anemia. 
There is no gender predilection. 
Highest incidence occurs in individuals of African descent, followed by eastern Mediterranean and Middle Eastern populations. 
The sickle cell mutation is prevalent in part as it confers a human genetic resistance to malaria as the abnormal hemoglobin has higher turnover and increased phagocytosis while sickled red cells have reduced cell-cell cytoadherence preventing the parasite from multiplying during the erythrocytic phase of its life cycle. It is estimated that approximately 8% of the African population is homozygous for sickle cell where malaria is most prevalent.
The earliest manifestation is usually in early childhood, as babies are protected by elevated levels of fetal hemoglobin (HbF) in the first 6 months3. 
Commonly a painful vaso-occlusive crisis, sudden onset of bone or visceral pain due to microvascular occlusion and ischemia.
Three separate mechanisms can result in skeletal changes: 
1. chronic anemia resulting in expansion of the medullary spaces
2. vaso-occlusive crises resulting in bone infarcts and subperiosteal hemorrhages

3. infection, osteomyelitis.


MRI study of brain reveals:
Diffuse cerebral cortical atrophy.
Enlarged Peri vascular spaces involving bilateral Cingulate gyri, corpus callosum.
Diffuse thickening of bony calvarium.
J shaped Sella.

MRI study of Spine reveals:
Bullet-shaped vertebra at multiple levels.
Dorsal dermal sinus in sacral region extending towards S4 without fusion or segmentation anomaly. No obvious cord tethering.
Spleen 10 cm, moderate splenomegaly.
Liver 12 cmM mild to moderate hepatomegaly.

Possibility of Mucopolysaccharidosis suggested for further clinical evaluation.

Ewing's Sarcoma MRI Spine

A young male with progressive paraplegia.
A lentiform shaped well defined posterior epidural soft tissue in mid dorsal region with marked homogeneous enhancement on post contrast causing severe cord compression, abnormal intra medullary signals in compressed cord. There is an associated altered marrow signal, marrow oedema involving neural arch of adjacent vertebra with mild expansion of spinous process of corresponding vertebra.

Imaging wise differential  diagnosis considering young age of patient:
Ewing sarcoma, osteosarcoma, round cell tumour, aggressive haemangioma, Haemangiopericytoma.

Operated with posterior Decompressive laminectomy, excision of tumour.

Histopathology Report : Ewing Sarcoma.

Crossed Cerebellar Diaschisis CT Brain

For similar case Click here

Crossed cerebellar diaschisis

Refers to a depression in function, metabolism and perfusion affecting the cerebellar hemisphere as a result of contralateral supratentorial lesion.
This disturbance occures in a portion of the brain at a distance from the original site of injury but connected via white matter tracts.
Initially this phenomenon was defined as being caused by an acute lesion but now considered being related to a lesion of any temporal duration.
Other than neurological deficits and clinical features associated with the contralateral supratentorial lesion, this condition is generally asymptomatic.
This is a well-recognised phenomenon following cerebral infarction, although it can be a sequela of any significant supratentorial lesion like tumours, intracerebral haemorrhage, encephalitis , Dyke-Davidoff-Masson syndrome, Radiation necrosis etc.
There is no treatment for this phenomenon other than management of the supratentorial insult and prevention of further insults.

Brachial plexitis MRI

MR Neurography of Brachial Plexus
Clinically :  middle-aged male with left arm pain and weakness of sudden onset. No history of trauma. No history of radiotherapy.

MR Neurography of brachial plexus show diffuse enlargement with abnormal T2 hyperintensity iinvolving left brachial plexus nerves. Mild enlarged bilateral deep cervical group of lymph nodes.

Imaging diagnosis: Left side brachial plexitis.

Brachial plexitis

An inflammatory change involving the brachial plexus commonly seen in men between 30 to 70 years of age and is bilateral in 10-30% of patients .

post radiation plexitis: usually presents 5-30 months after treatment.
viral brachial plexitis, e.g. cytomegalovirus, Coxsackie, herpes zoster, Epstein-Barr virus, parvovirus B19
toxic (related to previous serum, vaccine, antibiotic or other drug administration, human immunodeficiency virus serology)
recent surgery
Lyme disease
heredofamilial hypertrophic neuropathies like Charcot-Marie-Tooth disease, Dejerine-Sottas disease, chronic inflammatory demyelinating polyneuropathy.
idiopathic ; Parsonage-Turner syndrome.

Diagnostic clues on MR Neurography are diffuse enlargement of nerves of brachial plexus with abnormal T2 hyperintensity and enhancement on post contrast MRI.

Amyotrophic Lateral Sclerosis MRI

Clinical Details  : 45 yo male, from last five months has been having slowly progressive right distal arm, hand and recently right leg weakness which seems to be progressive. There is no sensory symptoms. No bowel bladder disturbance. Recently has also noted some slurrring of speech and tremulousness of both hands. Clinical examination shows poly myoclonus. Hyper reflexia, right plantar is extensor. Mild right facial weakness, eye movements are normal. Sensations are normal.

Clinically suspected Amyotrophic Lateral Sclerosis.
MRI Findings:
Contiguous bilateral symmetric T2 hyperintensity along posterior limb of internal capsule, extending in adjacent Corona radiata and along cortical spinal tract portion of Brainstem.
MRI DWI images normal.
Normal MR Angiography of Brain.
Finding consistent with clinical diagnosis of Amyotrophic Lateral Sclerosis.

Amyotrophic Lateral Sclerosis 

Lou Gehring disease, A motor neuron disease.

Can be defined as a selective degeneration of somatic motor neurons of Brainstem, spinal cord that is lower motor neuron, pyramidal neurons of motor cortex that is upper motor neuron and eventual loss of corticospinal tract fibres.

Diagnostic clue on imaging is bilateral symmetric contiguous long segment T2 hyperintensity extending along corticospinal tract from motor cortex at Precentral gyrus through bilateral corona radiata, posterior limb of internal capsule, Brainstem and onwards.

Imaging differential diagnosis is Distal Wallerian degeneration in which signal abnormality is often unilateral, associated with primary lesion like bleed or infarct if bilateral has to be asymmetric.
Other conditions with T2 hyperintense lesion at various levels of corticospinal tract are metabolic like x linked adrenoleukodystrophy, Wilsons disease, hypoglycaemic comma, demylinating and inflammatory diseases like multiple sclerosis, ADEM, Behcets disease.

Please make one important note that corticospinal tract can appear hyperintense on 3 Tesla MRI due to Fractional anisotrophy related artefacts in a normal fully demylinating brain at any age and mimic Amyotrophic lateral sclerosis. So clinical back up is important before giving the diagnosis solely based on imaging.

Majority of cases are sporadic but in 15 to 20% of cases they are familial. Common in 4th to 7th decade of life. Twice common in males.
Clinically upper motor signs like Babinski sign, spasticity, hyperreflexia andd lower motor neuron signs like asymmetric muscle weakness, atrophy, fasciculation, Hyporeflexia should be looked for.