Wednesday, 11 March 2020

Tuberous Sclerosis

 
This CT and MRI study of brain shows:
Multiple dense nodular calcifications along enpendymal lining of bilateral lateral ventricle best seen on CT. Cortical tubers seen as small multi focal cortical and sub cortical white matter patchy hypodensities on CT and T2 hyper intensities on MRI. No obvious obstructive hydrocephalus.

The lesion at right caudo thalamic groove not calcified on CT but shows avid enhancement on post contrast, needs follow up imaging as it may turn out to be a sub ependymal giant cell astrocytoma leading to obstructive hydrocephalus. However as of now there is not obvious obstructive hydrocephalus.

Imaging diagnosis : Tuberous Sclerosis.

TUBEROUS SCLEROSIS

Syn: Tuberous sclerosis complex (TSC), Bourneville-Pringle Syndrome.
A inherited tumor disorder with multi-organ Hamartomas.

In CNS characterized by Subependymal nodules, Subependymal giant cell astrocytoma, Cortical/subcortical tubers.
Abnormal differentiation/proliferation of germinal matrix cells, Migrational arrest of dysgenetic neurons appears to be the pathogenesis behind the lesions.
Histopathology and microscopic features are Balloon cells, Myelin loss, vacuolation and gliosis, Ectopic neurons.

Imaging 

CT and MRI both are equally sensitive but MRI often shows more number of lesions.
Subependymal nodules
Seen in ~ 98%. Commonest and specific site is caudothalamic groove followed by atrial and temporal lobe white matter.
~ 50% them shows an associated calcification best depicted on CT. calcification is often progressive after 1 yr.
30-80% of SEN shows mild enhancement on post contrast study, appreciated better on MRI than CT.
SEN at foramen of Monro needs close follow. If its enlarging it is equivalent to Subependymal giant cell astrocytoma (SGCA) and can cause obstructive hydrocephalus.
Subependymal giant cell astrocytoma (SGCA)
Seen in ~15%.
Cortical/subcortical tubers, WM lesions
Seen in ~ 70-95% common in Fronto parietal followed by temporo occipital regions and Cerebellum.
Ill defined patchy hypodensites on CT +/- calcification.
Hypo intense on T1 hyper intense on T2 and FLAIR on MRI. No restricted diffusion. May show low signal intensity on T2*GRE if an associated calcification.
~12% cortical/subependymal tubers show faint enhancement on post contrast T1.
Cyst-like white matter lesions as focal lacune best seen on MRI T2w images, common in corona radiata.
An associated thickened cortex, enlarged gyri.
MRS: decreased NAA/Cr, increased ml/Cr in subcortical tubers, SENs.

Associated abnormalities

o Renal: Angiomyolipoma and cysts 40-80%
o Cardiac: Rhabdomyomas 50-65%; majority involute over time
o Lung: Cystic lymphangiomyomatosis/fibrosis
o Solid organs: Adenomas; leiomyomas
o Skin: Ash-leaf spots (majority) including scalp/hair; facial angiofibromas; shagreen patches 20-35% post pubertal
o Extremities: Subungual fibromas 15-20%; cystic bone lesions; undulating periosteal newbone formation
o Ocular: "Giant drusen" (50%)
o Dental pitting permanent teeth in most adults with TSC

DDs: 

Subependymal heterotopia : Isointense to GM, don't enhance or Ca++.
TORCH : Periventricular Ca++ , White matter lesions, Cortical dysplasia common with Cytomegalovirus (CMV).
Taylors dysplasia

Genetics

De novo = spontaneous mutation/germ-line mosaicism
Autosomal dominant, high but variable penetrance. Approximately 50% of TSC cases are inherited.

Clinical presentation

Classic clinical triad
1. Facial angiofibromas 90%;
2. Mental retardation 50-80%;
3. Seizures /  Epilepsy 80-90%

All three ("epiloia") seen in ~ 30% of cases.

More the number lesion ~ high the neurologic symptoms.
Diagnosed at any age.

First year of life commonly present with seizures, Infantile spasms like episodes.
Child present with Autistic-like behavior, mental retardation, seizures, or skin lesions.
Adult may present for first time due to a symptomatic SGCA.

Treatment

Treat seizures.
Resect isolated tubers if seizure focus or if able to identify seizure focus among many tubers.
SGCAs resected if obstructing foramen of Monro.

Reference :

Diagnostic imaging Osborn.

Thursday, 5 March 2020

Hyperammonemia MRI

Clinically:  young female patient with short history of drowsiness, brought unconscious.
MRI brain shows bilateral fronto parietal, temporo parietal cortical T2 hyperintensity with restricted diffusion. Lab report mentions Patient’s serum ammonia was high.

Imaging diagnosis: 
Hyperammonaemia.

DDs:
Differential diagnosis considered were Posterior reversible encephalopathy, CJD (Creutzfeldt-Jakob disease). Possibility of posterior reversible encephalopathy, PRES was ruled out as blood pressure was normal and there was no intra or postpartum history of seizures, eclampsia.

Absence of dementia, very short clinical history and absence of cerebral cortical atrophy on MRI was against CJD.

Bilateral Facial Colliculus Syndrome MRI

Clinically: 35 year old female with sudden onset slurred speech since two days with associated giddiness, fever.
On neurological examination there was facial Palsy. No signs of internuclear ophthalmoplegia.
MRI BRAIN shows:
Bilateral symmetric abnormal T2 hyperintensity with mild focal parenchymal swelling involving dorsum of Pons at the floor of fourth ventricle.
Area of involvement corresponds to facial colliculus.

Imaging wise differential diagnosis:
Bilateral facial colliculus syndrome due to demyelinating lesion.
Viral infection, Rhombencephalitis.

Suggested CSF for oligoclonal band and serum immunoglobulin in view of Multiple sclerosis.
Antinuclear antibodies in view of autoimmune disease.
Routine CSF for viral infection.

Facial colliculus and facial follicle syndrome

Facial colliculus is an elevation on the floor of fourth ventricle in Pons under which there is a presence No nucleus is located with facial nerve axons traversing over it giving of bump like appearance.

Lesion involving facial colliculus present with Internuclear ophthalmoplegia, abducens nerve, lower motor neuron type of facial nerve palsy with an associated features of medial longitudinal fascicles involvement.
There is important to make note that not symptoms and signs will be present in each and every patient.

Causes of facial colliculus syndrome include demyelination for example multiple sclerosis, viral infection like Rhombencephalitis, tumour whereas it can be secondary to ischaemic infarct in old age patient.
Facial colliculus syndrome secondary to Stroke going to be uni lateral whereas demyelinating lesion will be more or less bilateral.

Tuesday, 18 February 2020

Choroid Plexus Papilloma MRI

Clinical details: A 2 y/o female child, h/o inability to maintain posture, inability to walk, delay in developmental milestones.
Enlarged head on inspection.


CHOROID PLEXUS PAPILLOMA

The most benign tumor of  choroid plexus.

Vast majority of choroid plexus papilloma occur in the lateral and fourth ventricle. Atrium is the most common site, usually solitary tumours varying in size from small to large. Occasionally multiple non contigious lesions are seen. Most of the are well circumscribed papillary or cauliflower like masses may adhere but usually do not invade through the ventricular wall.

Histologically the architecture of C.P.Ps closely resemble that of non-neoplastic choroid plexus. A core of fibrovascular connective tissue covered by a single layer of benign appearing epithelial cells is typical. Cytokeratins,Vimentins,and Podoplanin are expressed virtually by all C.P.Ps.
Choroid plexus papillomas are W.H.O grade 1 neoplasm.

C.P.Ps account for less than 1 % of all primary intracranial neoplasm but represent 13% of brain tumors occurring in 1st yr of life. Median age of presentation for lateral and third ventricular C.P.Ps is 1.5 yrs, for 4th ventricular C.P.Ps it is 22.5 yrs. There is slight male preponderance.
Headache,nausea, vomiting with enlarged head size may be seen in children and infants.

IMAGING FINDINGS:
Intra ventricular mass isodense to hyperdense compared to brain parenchyma on CT. Intense homogenous enhancement on post contrast.
A well defined , lobulated intraventricular mass with frond like papillary excression, iso to slightly hypointense compared to brain parenchyma is seen on T1W1, iso-to hyperintense on T2W1 and FLAIR. Linear and branching internal flow voids reflects the increased vascularity within choroid plexus papillomas. T2w images may show hypointense foci secondary to calcification.
Associated hydrocephalus due to overproduction of c.s.f.
Elevated myoinositol on MR spectroscopy.

Dr Prasad Jagdale
Radiology Resident
CNS Hospital, Solapur

Saturday, 7 September 2019

Ataxia Telangiectasia MRI


MRI brain shows:
1. Moderate grade diffuse cerebellar atrophy. No associated Brainstem or cerebral cortical atrophy.
2. Multiple punctate low signal intensity foci on GRE in bilateral cerebral white matter.

Imaging diagnosis: Ataxia-telangiectasia.

Ataxia Telangiectasia 

A rare multisystem condition with autosomal recessive inheritance, incidence at around 1:40,000-300,000 live births, sometimes classified as a phakomatosis.
Characterized by multiple telangiectasias, cerebellar ataxia, pulmonary infections and immunodeficiency.

Diagnostic clue on MRI brain is diffuse cerebellar atrophy, compensatory enlargement of the fourth ventricle, micro hemorrhages secondary to capillary telangiectasia.
Main clinical features include cerebellar ataxia progressive and present in all cases, associated oculomucocutaneous telangiectasias, susceptibility to pulmonary infection due to immunodeficiency.
Genetics, results from a defective gene located on chromosome 11q22–23.
Treatment is generally supportive.

Cysts in gyrus rectus of frontal lobe

Clinical Details  : 42 yo female, sometime in May 2019 suffered from an episode of un responsivity associated with no features to suggest a seizure. There was no excessive perspiration. She however regains consciousness spontaneously after about 15 minutes. Thereafter she was well but on the 9th of August abruptly lost consciousness, had abnormal tonic posturing of the limbs, hyper salivation but no tongue bite or incontinence. SHe however had excessive profuse perspiration. 

Present clinical examination is entirely normal. 
BP 130/90

MR study of brain reveals multicystic changes clustered in the gyrus rectus of right frontal lobe.
Clinical significance is doubtful in this case.
However this is a rare finding so far reported only with tourette syndrome in literature.

Ref :
Tourette syndrome associated with unilateral cystic changes in the gyrus rectus.
McAbee GN1, Wark JE, Manning A Department of Pediatrics (Neurology), University of Medicine and Dentistry of New Jersey, Children's Regional Hospital at Cooper Hospital/University Medical Center, Camden 08103, USA.

Sunday, 1 September 2019

Tumor Mimics MRI

FLAIR
T2W
DWI
T2*GRE
T1


MR SPECTROSCOPY
PERFUSION IMAGING

This MRI study of brain shows an intra axial space-occupying lesion measuring approximately 53x55mm involving left opercular parietal and adjacent insular cortex with marked focal parenchymal swelling, lesion non-enhancing on post contrast. No mid line shift or mid brain compression. No obvious cystic or necrotic component. No diffusion restriction or haemosiderin staining on GRE.

ASL 
3D arterial spin labelling (non-contrast perfusion) was performed. Cerebral blood flow (CBF) assessed in ml /100 gm / min

Findings: 
The lesion predominantly shows mixed perfusion, major portion show hypo perfusion with patchy areas of relative hyper perfusion with CBF in range of 11 ml / 100 gm / min , 160% of reference in its cranial aspect. 

PERFUSION IMAGING
Perfusion maps demonstrated with color scale used are as follows. 
CBF: cerebral blood flow; higher scale (red) means faster flow and lower scale (blue) mean less flow.
CBV: cerebral blood volume ; higher scale (red) means more volume and lower scale less volume.
MTT: mean transit time; higher scale (red) means longer time required to washout contrast and lower scale (blue) means short time early washout.
TTP: time to peak; higher scale (red) means longer TTP and lower scale (blue) means shorter TTP.

Findings:
Lesion is relatively hyper perfused. 
rCBF:          11  ml/100gm/ min   160% of reference
rCBV:        3.2   ml / 100gm tissue 482% of reference
MTT:        17; 296% of reference   

Interpretation:

Lesion show mixed perfusion, areas of hypo - iso perfusion, a focal hyper perfusion particularly left parietal sub cortical portion of lesion. 

MR SPECTROSCOPY 

Axial T2w localizer taken and multi voxel MR Spectroscopy performed. The voxel of size 2x2cm placed over the lesion. Water suppression obtained was 99% with optimum spectral waveform obtained at short as well as long TE.

Metabolites evaluated on short TE of  35ms and TR of 1500ms from right to left as follow. 
At 2.01ppm – short and wide peak of NAA. NAA is reduced.
At 3.03ppm – sharp and long peak of Creatinine. Creatinine is reduced.
At 3.2ppm – sharp and long peak of Choline. High choline.
No lipid lactate.

NAA/ Creatinine ratio is 2
Choline/ Creatinine ratio is 1.5

Interpretation: 

Lesion show high choline, reduced Creatinine. 

Summary: 

This MRI study of brain shows an intra axial lesion involving left opercular parietal and adjacent insular cortex with marked focal parenchymal swelling, sub cortical white matter oedema, non-enhancing on post contrast. No obvious cystic or necrotic component. 
No diffusion restriction or haemosiderin staining on GRE.
Lesion show high choline, reduced Creatinine on MR spectroscopy. 
Left parietal sub cortical portion of lesion is hyper perfused on ASL as well as perfusion imaging.

Imagingwise diagnosis: Glioma like Astrocytoma_ Low to Intermediate grade tumour.
But Histopathology report surprise to me.

HISTOPATHOLOGY REPORT : FOCAL CORTICAL DYSPLASIA TYPE III

Microscopic Description : 

The entirely submitted material shows surrounding odematous glial tissue. Punctate haemorrhages, fine micro cystic change, neuronal crowding, Cytomegaly neurons, Peri vascular cuffing and haemorrhages, Occasional Balloon cells. There is no granuloma. 
IHC : Ki 67 index less than 1 %

Post traumatic Neuroma MRI

A 35 old male fell from 8 feet and experienced immediate spine and both hip pain with progressively worsening back pain that radiated to right hip and right lower extremity. Sharp pain radiated from back to toes, and experienced paresthesias from right knee to toes.
On examination, antalgic gait and unable to walk, weakness of right hip flexion, knee extension, ankle dorsiflexion and ankle plantar flexion. A straight leg raise test result was positive on the right at 15°, which indicated neuronal irritation, and was negative on the left leg.
MRI WHOLE SPINE show multiple level benign post-traumatic sub chondral collapses with marrow oedema. No obvious listhesis.
Study extended with MR Neurography of lumbosacral plexus shows a well-defined ovoid mixed but near cystic signal intensity lesion on right side of spine at lumbosacral junction deep to the right psoas muscle. Lesion is ovoid has typical teardrop shape with proximal portion tapering towards neural foramina suggestive of neural/perineural origin of lesion.
Considering history of trauma possibility of post-traumatic neuroma was suggested.

Histopathology examination : Neuroma.
Microscopy shows a disorganized fibroneural tissue contained randomly oriented nerve twigs surrounded by attenuated connective tissue and different types of cells like Schwann cells, macrophages, and fibroblasts, which may extend into adjacent adipose tissue.

Final diagnosis: Post traumatic Neuroma.

Post traumatic Neuromas (PTNs) of Lumbar Plexus

PTNs may be terminal occuring in amputation stumps or when the nerve is completely transected, or they may be in-continuity. Neuromas-in-continuity comprise most nerve injuries from laceration, contusion, or stretch injury.

A peripheral nerve MR Neurography an useful technique for the preoperative diagnosis, localization, and characterization of nerve abnormalities, including PTN formation.

Neuromas present as a fusiform mass with nerve continuity, may be similar in appearance to that of neurogenic tumors, such as schwannomas and neurofibromas. Neuromas unlike neurogenic tumors may not show enhancement. Unlike neurogenic tumors, neuromas-in-continuity lack a split fat sign, which represents a rim of fat that surrounds the tumor, particularly in relation to the proximal and distal portion of the nerve best appreciated on T1-weighted images. Neuromas-in-continuity also lack a target sign, which consists of high signal intensity in the periphery and low signal intensity in the central region of the lesion on T2-weighted images. PTNs of the peripheral nerves have been reported and tend to be low to isointense on T1-weighted imaging and hyperintense on T2-weighted imaging.

Lumbosacral PTN is relatively rare. Radiologists should be aware of the imaging appearance of injury-related neuromas for appropriate diagnosis and avoid misinterpretation as true neoplasms. 

Posterior Epidural Fibrosis Arachnoiditis MRI


MRI LUMBAR SPINE WITH CONTRAST

Changes of lumbar spondylosis. Evidence of laminectomy at L4 - L5, mild disc bulge.
Diffuse homogeneously enhancing posterior epidural T2 hypo intense soft tissue at laminectomy site, clumping of nerve roots appears adherent to dura at laminectomy level. Available anteroposterior bony canal diameter is approximately 14 mm. L5 sacralisation.

Possibility of posterior epidural fibrosis with an associated arachnoiditis suggested for further clinical evaluation.

Sjogren's syndrome MRI Brain


Clinically 40 yo female, a known case of Sjogren's syndrome without any neurological or psychiatric complaints.
Stable well oriented with no signs on neurological examination.

MRI brain shows confluent T2 hyperintensity in bilateral cerebral white matter, corona radiata, external capsules, bilateral dentate nuclei.
No associated cerebral cortical atrophy.
Imaging finding can be labelled as severe changes of small vessel disease, significant for age.

Sjögren syndrome and MRI brain

Sjögren syndrome is a chronic systemic autoimmune disease affecting 2–3% of adults.
Classified as primary when occurring in isolation and as secondary when associated with another autoimmune disease.
Characterized by mononuclear infiltration and destruction of the exocrine glands, mainly the lachrymal and salivary glands, resulting in xerophthalmia and xerostomia.
Apart from the glandular features, mononuclear infiltration of visceral organs and vasculitis can give rise to extraglandular manifestations like arthralgia, pulmonary involvement, renal tubular acidosis.
Neurologic involvement in primary Sjögren syndrome particularly peripheral nervous system involvement is a well-documented feature of the syndrome in about 20–25% that commonly manifests as peripheral sensory neuropathy or mononeuritis multiplex caused by small-vessel vasculitis.

MRI brain of patients with primary Sjögren syndrome has shown multiple areas of increased signal intensity in the periventricular and subcortical white matter on FLAIR and T2-weighted images.
Important to note is this have been observed in both patients with and without CNS impairment or symptoms as in our case. Brain atrophy has been reported in a limited number of studies of patients with primary Sjögren syndrome.

Reference : https://www.ajronline.org/doi/10.2214/AJR.10.5984.