Sunday, 8 July 2018

Pituitary stone

Clinically a known case of pituitary macro adenoma, prolactinoma as lab reports were showing high levels of prolactin. Under regular treatment of Bromocriptine.
CT SAG REFORMATTED IMAGE
CT SAG REFORMATTED IMAGE
MRI BRAIN SAGITTAL T2W IMAGE
Pituitary stone

Also known as pituitary lithiases or pituitary calculus.
A very rare entities defined as extensive calcifcation in the sella turcica.

There is inconsistency regarding what pituitary stones actually are. Some authors suggest the term be used only for calcifications in the sella turcica that occur in the absence of any other pituitary pathology, others use this term more liberally to describe excessive calcification from any cause, such as pituitary adenoma.

Epidemiology
Although the exact incidence is unknown, this entity is generally considered to be very rare as there are only 1 to 6 case reports of idiopathic calcifications so far. However, calcification in pituitary adenoma is considered more common which is approximately 10%.

The aetiology of 'primary' de-novo pituitary stones remains an enigma but is thought to be secondary to an unknown inflammatory process, subclinical haemorrhage, or cartilaginous metaplasia.
In cases secondary to other pathologies, most commonly pituitary adenomas, especially in prolactinomas, is thought to be a sequelae of fibrosis secondary to haemorrhage.

Other secondary causes rare and include Pituitary tuberculosis, metabolic imbalances like hypercalcaemia, sequel of pituitary apoplexy.

Clinical presentation varies significantly, may be entirely asymptomatic or endocrinopathies such as hypopituitarism, hyperprolactinaemia from an underlying pituitary adenoma or hemorrahge.

Imaging
CT is the modality of choice, best demonstrated on sagittal reformatted images as in this case, where they appear as well defined hyperdense nodule in the sella turcica. On MRI, signal changes are consistent with calcification that is low signal on T1, T2 as well as GRE without enhancement on post contrast.

Treatment and prognosis
Presence of stone in a macro adenoma not going to change line of management, treatment should be directed towards underlying cause. It should be left alone if idiopathic and asymptomatic.

Differential diagnosis off course in absence of macroadenoma should include calcified Rathke cleft cyst, calcified meningioma and calcified aneurysm in pituitary region. 

Vit B12 deficiency MRI brain findings

Clinically young female with psychiatric complaints like altered behaviors and generalized weakness.

MRI FLAIR images of brain shows bilateral fronto parietal and temporal peri ventricular confluent T2 hyper intensities. DDs given were Viral encephalitis like HIV encephalitis, ADEM, Toxic Metabolic encephalopathy. MRI screening of spine shows no obvious spinal cord involvement.

Lab report showed significantly low level of Vit B12 suggestive of isolated brain involvement in B12 deficiency. Patient improved with Vit B12 supplements.

Vitamin B12 deficiency 

Vitamin B12 or Cobalamin deficiency causes a wide range of hematological, gastrointestinal, psychiatric and neurological disorders.
Neuropsychiatric symptoms may precede hematologic signs and are represented by myelopathy, neuropathy, dementia and visual loss due to optic nerve atrophy. 

Causes 
A strict vegetarian diet contains very little cobalamin. There is clear evidence of abnormal cobalamin metabolism in vegetarians and hyper-homocysteinemia is a risk factor, especially for stroke and vascular dementia, vegetarians are advised to take cobalamin supplements lifelong.
In developed countries, the diet is rich in meat and cobalamin-rich foods; thus, malabsorption is the most common cause of cobalamin deficiency. 
Infants born to vegetarian mothers are at risk of cobalamin deficiency and may present with megaloblastic anemia.

Clinical and Hematological Manifestations ranges from incidental increased mean corpuscular volume and neutrophils hypersegmentation in otherwise asymptomatic patients to symptoms due to severe anemia, such as angor, dyspnea on exertion, fatigue or symptoms related to congestive heart failure, such as ankle edema, orthopnea and nocturia. 

Neuroimaging
Vitamin B12 deficiency may affect both the central (brain, spinal cord and optic nerve) and the peripheral (peripheral nerves) nervous system.
The spinal cord involvement is associated with the most frequent manifestation of vitamin B12 deficiency, namely subacute combined degeneration (SCD), is characterized by symmetric dysesthesia, disturbance of position sense and spastic paraparesis or tetraparesis. The most consistent MRI finding is a symmetrical abnormally increased T2 signal intensity, commonly confined to posterior columns in cervico dorsal spinal cord ' inverted V' configuration. 

Isolated brain involvement has also been reported in B12 deficiency but is rare in adults. 
MRI shows confluent T2 high-intensity signal in periventricular white matter.
Isolated brain involvement is common in children with inherited cobalamin-related diseases characterized by white matter loss with delayed myelination.
In infants with nutritional cobalamin deficiency MRI has revealed delayed myelination.

Therapy is definitely Vitamin B12 supplements oral or intra muscular. 

Hemangioblastoma MRI

PC CT BRAIN
FLAIR
T1
DW
GRE
T2
T1 PC
PC T1
PC T1
Hemangioblastoma

A highly vascular tumor.
An intra axial posterior fossa mass with cyst and an enhancing mural nodule is a diagnostic clue.
Currently classified as meningeal tumor of uncertain histogenesis (WHO, 2000)

Locaion:
90% posterior fossa (m/c) in that 80% cerebellar hemispheres, 15% Vermis, 5% in other places  fourth ventricle, medulla.
10% Supratentorium.
In ~ 60% of cases mass present as cyst + mural nodule and in ~ 40% of cases only as a solid nodule.

Imaging findings:
Cyst is clear, density on CT and signal intensity on MRI same as that of Csf, non enhancing thin imperceptible wall.
Mural nodule on CT may be iso to hyper dense, intense and homogenous enhancement. On MRI hypo to iso intense on T1, hyperintense on T2 and FLAIR. May see flow voids within the nodule with adjacent vascular feeders on T2w images, intense and homogenous enhancement on T1 images implies to its highly vascular nature. May show low signal intensity hemosiderin staining on GRE if associated to with any bleed.

Presentation is usually with headache, dysequilibrium, dizziness may be due to its mass effect and hydrocephalus.
Age : for sporadic: 40-60 yr and for familial : can occur at younger age. Slight male predominance.

Closest DD is Pilocytic Astrocytoma; mural nodule show mild to moderate enhancement not this intense, not characterized by flow voids and feeders. Seen in relatively younger age group.

Posterior cortical atrophy MRI

Clinically : progressive dementia, not responding to Csf drainage. 
Here is MRI BRAIN compared to previous MRI. 
FOLLOW UP MRI
PREVIOUS MRI DATED 8 JULY 2014
Salient feature of this MRI is bilateral posterior cortical atrophy.
There is moderate grade Atrophy involving bilateral parietal lobes, appears to be progressive as it has increased compared to previous MRI dated 8 July 2014. An associated marked mid brain atrophy. No obvious signal abnormality on diffusion weighted images.

Differential Diagnosis:
Benson's syndrome, an atypical variant of Alzheimer's disease.
Levy body dementia.

CJD.

Crossed cerebellar diaschisis MRI




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.

Thursday, 21 September 2017

Giant Tumefactive Perivascular Spaces MRI

Clinical Details: headache.
FLAIR
T1W
T2W
T2*GRE
T1 PC
MRI brain with Contrast

MRI study of brain with contrast shows a well defined, multilocular cystic lesion isointense to CSF, non-enhancing on post contrast involving left thalamus, adjacent mesencephalic mid brain. An associated mild mass effect causing third ventricle compression however no obvious obstructive hydrocephalus. No obvious low signal intensity haemosiderin staining on GRE. No obvious adjacent perilesional oedema on FLAIR.

Imaging findings suggestive of giant Tumefactive Peri vascular space – a benign non-tumoural cyst.
Suggested follow-up imaging for mass effect.

Giant Tumefactive Perivascular Spaces

Perivascular spaces (PVSs) are pial-lined, interstitial fluid-filled structures that accompany penetrating arteries, also known as Virchow-Robin spaces when enlarged, they may cause mass effect and can be mistaken for various ominous pathologic processes.
Often appear as clusters of variably sized cysts that are isointense to CSF on all pulse sequences and do not enhance, Gaint Tumefactive VR spaces assuming bizarre configurations with striking mass effect should not be mistaken for neoplasm.
They are most common in the mesencephalo thalamic region and may cause hydrocephalus.

Reference: Giant Tumefactive Perivascular Spaces Karen L. Salzman, Anne G. Osborn, Paul House, J. Randy Jinkins, Adam Ditchfield, James A. Cooper and Roy O. Weller
American Journal of Neuroradiology February 2005, 26 (2) 298-305



Japanese encephalitis MRI

Clinical Details : fever with seizures, loss of consciousness.
Clinically no history of poisoning or primarily metabolic derangement.




This MRI study of brain FLAIR and Diffusion shows abnormal T2 hyperintensity with marked parenchymal swelling, bilateral and Symmetrically involving thalami, Pons, bilateral cerebellar hemisphere with restricted diffusion. Confluent T2 hyperintensity Bilateral Symmetrically involving fronto parietal Peri ventricular white matter.
Oedematous thalami causing Third ventricle compression leading to mild dilatation of lateral ventricles. Diffuse cerebral oedema.
Normal MR venography of brain.

Imaging wise differential diagnosis:
Viral encephalitis Japanese encephalitis
Toxic/Metabolic leukoencephalopathy.

Japanese encephalitis

Causative agent is Japanese encephalitis virus , a single-stranded RNA flavivirus.
Domestic pigs and wild birds are reservoirs for the virus, spreads by mosquitoes. Disease is prevalent in India, South East Asia.

Clinical presentation is usually rigors, fevers and headache.
Neck rigidity, cachexia, hemiparesis and convulsions as signs of meningitis as disease progresses.

Bilateral thalamic involvement is classical as hypodensities on CT and T2 hyperintensities on MRI with restricted diffusion, marked a focal parenchymal swelling. Associated midbrain, pons, cerebellum, basal ganglia, cerebral cortex and spinal cord involvement is well known. Imaging after 3-4 days of the onset may reveal haemorrhage giving rise to low signal intensity haemosiderin staining on GRE.

Treatment is only supportive with higher mortality rate. Vaccination may be preventive in endemic areas.

Differential diagnosis
Other infectious causes that can cause a similar imaging pattern are Murray Valley encephalitis, West Nile fever, eastern equine encephalitis, herpes simplex encephalitis.
However in Herpes which is promptly treatable with antivirus treatment, the medial temporal lobe involvement is classical with uncommon thalamic involvement.
Bilateral thalamic haemorrhage in Japanese encephalitis is often confused with deep cerebral vein thrombosis. So it is important to run MR venography to demonstrate normal straight sinus.

Friday, 18 August 2017

Fukuyama Congenital Muscular Dystrophy MRI


Clinically:
Brachycephaly.
Hypotelorism, convergent squint
Delayed milestones.



MRI study of brain shows:
Bilateral symmetric frontal lobar Poly micro gyria.
Diffuse cerebral cortical atrophy with mild dilatation of lateral ventricles.
Bilateral Cerebral Periventricular as well as sub cortical white matter show symmetric confluent T2 hyperintensity with white matter paucity suggestive of hypo myelination.
Marked atrophy of Brainstem particularly Pons, hypo plasia with a typical midline cleft.
Bilateral cerebellar hemispheres show multiple T2 hyperintense small cysts with micro folia attributed to an associated cerebellar dysplasia, Polymicrogyria with mild hypo plasia of cerebellar vermis. Postero fossa normal sized.
Bilateral Basal ganglia and thalami spared.

Imaging findings are typical of Fukuyama Congenital Muscular Dystrophy.

Reference : American Society of Neuroradiology : Fukuyama Congenital Muscular Dystrophy

Fukuyama Congenital Muscular Dystrophy

Heterogeneous group of inherited disorders characterized by myopathy and hypotonia at birth. 
Rarely occurs outside the Japanese population.
Autosomal recessive inheritance; gene locus identified on chromosome 9.
The disease onset typically occurs in early infancy. Initial symptoms may include a poor suck, weak cry, floppiness, symmetrical generalised muscle weakness and hypotonia. Facial myopathy may also be seen and increases with age. Developmental and speech delay occur in all individual with FCMD. Other symptoms include seizures, clinical features related to cardiomyopathy, and cardiac failure. Survival beyond 20 years is uncommon, and death usually occurs following respiratory complications.
The diagnosis of FCMD is usually established by clinical features, characteristic findings on neuroimaging, and serum CK concentration. Molecular genetic testing, when available, is usually performed to confirm the diagnosis.
Key Diagnostic Features are cerebral and cerebellar polymicrogyria with accompanying cysts, and mild ventricular dilatation. Uncommonly, agenesis of septum pellucidum can be seen.
Rx: Supportive therapy.

Sunday, 15 January 2017

Orbital Calcifications

Case: 1
This is a 50-year-old man who underwent CT for headache.
Calcification of the trochlea
Calcification of the trochlea
CT demonstrates punctuate calcification in the anterior, medial and superior corner of the orbit.

Calcification of the Trochlea

Clinical presentation: Incidental finding.
Imaging findings: CT demonstrates punctuate calcification in the anterior, medial and superior corner of the orbit. The location is important not to be mistaken as a high-density foreign body.
Unilateral / bilateral symmetric.

The trochlea is a cartilaginous structure with a synoviumlined sheath that permits unimpeded movement of the superior oblique muscle. The tendon of the superior oblique muscle passes through the trochlea before it inserts along the supero-lateral portion of the globe. Calcification of the trochlea is often seen in elderly patients (25-30% in persons over 50 years old) and considered as degenerative change without clinical significance.
However, if the patient is younger than 40 years of age, there is a statistically significant correlation with diabetes and these findings should prompt an endocrine evaluation.
Other less common causes of trochlear calcification are Brown’s syndrome, traumatic and postsurgical changes.

Case 2:
This is a 16-year-old adolescent who presented with slowly progressive vision loss in the left eye.
Choroidal osteoma
CT demonstrates a plaque-like calcification in the posterior pole of the affected eye.

Choroidal Osteoma

Clinical presentation: new onset of blurry, distorted vision.
Imaging findings: CT demonstrates a plaque-like calcification in the posterior pole of the affected eye.

Choroidal osteomas are rare, benign, ossifying, choroidal tumors of unknown etiology. Histopathologic evaluation reveals mature bone with marrow space containing loose fibrovascular tissue. They occur predominantly in young females (90%) without a history of systemic or ocular disease, and are usually unilateral (75%). On ophthalmologic examination, they appear as yellow-white to orange-red plaques and are generally located in the macula or juxtapapillary region around the optic disc extending toward the macula. Variability in color occurs secondary to thinning, depigmentation, and hyperplasia of the overlaying retinal pigment epithelium.
They are typically oval in shape with well-defined scalloped margins. They may display progressive growth patterns, although regression in size has also been reported.

Complications include choroidal neovascularization (CNV), which can result in vision loss and subretinal hemorrhage. Retinal detachment is also common.
Ultrasound and CT are of particular value in diagnosing choroidal osteoma.
With B-mode sonography, choroidal osteoma shows increased echogenicity posteriorly within
the globe, with posterior acoustic shadowing, creating the “pseudo-optic nerve appearance.” On CT, choroidal osteomas are flat calcified lesions, less than 2 mm in thickness, within the posterior pole of the globe. They are typically located in the juxtapapillary region, and typically do not involve the center of the optic disc, which aids in differentiation from optic drusen.
Given their benign nature, choroidal osteomas are typically followed clinically. Identification of complications, particularly choroidal neovascularization, warrants treatment
given the risk of vision loss.
DD:
• Optic drusen.
• Choroidal metastases:
• Choroidal hemangioma.
• Hyaline plaque.

Case 3:
This is a 65-year-old man who underwent CT for headache.
Hyaline plaque
CT demonstrates punctuate calcifications on the surface of the globe at the 3 and 9 o’clock location

Scleral Calcification: Hyaline Plaque

Clinical presentation : Incidental finding.
Imaging findings: CT demonstrates punctuate calcifications on the surface of the globe at the 3 and 9 o’clock location and are usually bilateral. Common areas of degenerative hyaline plaque formation are at the insertions of the medial and lateral rectus muscles. It is thought that these calcific deposits are of no clinical significance. These patients are usually older than 80 years of age; however, this condition can be seen earlier in patients with a history of cataract surgery or other infectious or inflammatory conditions.
On CT, there is a clearly defined focal high-density lesion at the insertions of the medial and lateral rectus muscle, again typically at 3 and 9 o’clock locations. These lesions
are difficult to visualize on MRI, although a signal-void can occasionally be identified.
Metallic or glass foreign bodies can show a similar appearance. Therefore, careful evaluation of the location of high-density lesions is critical. Hyaline plaques are seen in the typical surface locations in elderly patients, and should be easily distinguished from high-density foreign bodies.

DD:
Foreign body.
Optic drusen seen in the surface of the optic disc, which become calcified with advancing
age. However, drusen can be seen in relatively young patients.
Choroidal osteoma is a benign, ossifying, choroidal tumor of unknown etiology. It occurs predominantly in young females with no history of systemic or ocular disease, and usually unilateral.

Case 4: 
This is a 68-year-old man who underwent CT for headache.
Optic drusen

CT demonstrates a punctuate calcification at the optic disc.

Drusen

Clinical presentation : Incidental finding.
Imaging findings: CT demonstrates a punctuate calcification at the optic disc.

Drusen is caused by the accumulation of mucopolysaccharides and proteinaceous material on the surface of the optic disc, which can become calcified with advancing age.
There is an inherited form with an autosomal trait with irregular penetrate.

Drusens are commonly asymptomatic and incidentally found on CT performed for other reasons. These lesions can cause visual field defects and rarely can also lead to deficits in central acuity. Approximately 75% of drusen are bilateral. They are usually seen in elderly patients, and are rare in children. They are also believed to cause headaches. The diagnosis of drusen is simplified when these
Lesions lie on the surface of the optic disk, where they can be easily detected on fundoscopic examination. When drusen lie deep within the tissue of the optic nerve, however, the typical fundoscopic appearance may not be evident. When these small lesions develop within the nerve tissue, they can lead to elevation of the disc, which can be diagnosed as papilledema
(pseudopapilledema). Under these circumstances, CT or MRI can be performed to look for conditions that may cause elevated intracranial pressure.

DD:
• Choroidal osteoma: Choroidal osteoma is a benign, ossifying, choroidal tumor of unknown etiology. It occurs predominantly in young females with no history of systemic or ocular disease, and usually unilateral.
• Choroidal hemangioma: Choroidal hemangioma is a benign vascular tumor with phebolith.
• Choroidal metastases: Metastatic choroidal tumors are not rare, although they are not very often appreciated clinically. Most common primary sites are breasts and lungs.
• Hyaline plaque: This is degenerative change and seen in elderly populations, usually more than 80 years old. Focal calcification is seen at the insertion of medial and lateral rectus muscles.

Case 5: 
30 y o male with history of firework trauma, foreign body. Now reduced vision.
Foreign body
CT demonstrates hyper dense foreign body in left orbital pre septal space.

Imaging findings: Most typical or important is nothing typical.  Often unilateral , can be bilateral but never symmetric.
Clinical presentation : Often Symptomatic. History of trauma is most often present followed by reduced vision with or without pain.

Friday, 6 January 2017

Artifact from Eye Makeup

This is a 45-year-old woman who underwent MRI for headache.
Axial MR image demonstrates signal loss and image distortion of the anterior portions
of the eyes. Image distortion is more significant with gradient echo
(field echo) imaging compared with other sequences. 
 
Eye makeup, both mascara and tattoo eyeliner can cause image distortion and signal loss associated with the use of iron oxide or other metal-based pigments. Therefore, the patient should be advised to remove eye makeups before MR exam, if possible, particularly when indicated to evaluate for abnormalities in the brain and face.

Slight “tingling” and sensation of “burning” have been reported in subjects who wear permanent cosmetics, however, the frequency and severity of soft tissue reactions or other problems related to MRI and permanent cosmetics is unknown. Therefore, permanent cosmetics should not prevent patients from undergoing MRI. Decorative tattoo has higher chance to cause worse complication compared to cosmetic tattoo. Radiologist or technician should be informed that the patient wears permanent makeup or tattoos before the exam and possible complication and artefact should be discussed with patients.