Right cerebellar infarct demonstrating luxury perfusion

Findings

CT shows right cerebellar hemispheric hypoattenuation with edema, mass effect, and effacement of the 4th ventricle. Angiogram shows contrast blush in the right inferior cerebellar hemisphere with an early draining vein ("luxury perfusion"). Anterior and inferior displacement of the right PICA branch. No evidence of vertebral dissection or vascular malformation.


Diagnosis: Right cerebellar infarct demonstrating luxury perfusion


Key points

Luxury perfusion is a term used to describe increased circulation through an area of infarcted brain.
Thought to be due do vasodilation secondary to lowered oxygen tension and decrease tissue pH. (Loss of normal CBF autoregulation).
Angiographically seen as capillary blush and early filling of local veins.
The blush may simulate a tumor
Luxury perfusion can be seen in minutes to hours after infarction, usually resolves in 3-5 days. Never seen after 2 weeks.

Persistent Trigeminal Artery (PTA)

Findings

In Figure 1, an artery can be seen branching from the cavernous portion of the left internal carotid artery and joining the basilar artery. Notice the absence of this vessel on the right.


Diagnosis: Persistent Trigeminal Artery (PTA)


In the 3-5 mm human embryo, approximately 29 days after ovulation, four important arterial anastamoses join the dorsal aorta (the future internal carotid artery) to the bilateral longitudinal neural arteries (the future basilar artery). They are the trigeminal, otic, hypoglossal and proatlantal intersegmental arteries. The largest of these is the trigeminal artery. These arteries persist about a week and regress as the posterior communicating and vertebral arteries develop. For reasons that are not fully understood, these arteries sometimes fail to regress.

The most common persistent carotid-vertebrobasilar anastamotic artery is the trigeminal artery. The incidence has been reported to be about 0.2%, but if undiagnosed and unreported cases are taken into account, this number may approach 1%. There are two main classifications of a persistent trigeminal artery based on its anatomic position; lateral and medial. The lateral type leaves the cavernous sinus to course with the trigeminal root on the lateral side of the sella turcica in a groove of the posterior petrosal process and joins the basilar artery between the origin of the anterior inferior cerebellar artery and superior cerebellar artery. The medial type penetrates the sella turcica to run in its own groove and perforates the dura near the clivus to join the basilar artery.

A persistent trigeminal artery is usually an incidental finding, but has been reported to present with several clinical manifestations. Patients with a persistent trigeminal artery are at an increased risk of developing aneurysms. These aneurysms can be located either at their origin from the internal carotid artery or at their connection with the basilar artery. Depending on the artery’s anatomic location relative to the trigeminal and abducens nerves, patients can present with trigeminal neuralgia or sixth nerve palsies. Patients can present with vertigo and ataxia from embolization of a carotid atherosclerotic plaque through a persistent trigeminal artery into the posterior circulation. Patients can present with the same symptoms with a carotid occlusion which can cause a vascular steal phenomenon from the basilar artery to the carotid system through a persistent trigeminal artery. Patients with complications from a persistent trigeminal artery can be treated with endovascular or surgical interventions.

Epidermoid Tumour Brain--MRI

On T1-weighted images epidermoids are generally slightly hyperintense or isointense relative to gray matter. The lesions are usually isointense relative to CSF on T2-weighted images, but they may be slightly hyperintense. Now, diffusion-weighted imaging can be used to differentiate these entities, because epidermoids have markedly restricted diffusion and, therefore, high signal intensity on the diffusion-weighted trace images. The free water in arachnoid cysts has low signal intensity.

Chiari malformation-MRI

Case by Teleradiology Providers

The cerebellar tonsils are elongated and pushed down through the opening of the base of the skull blocking the flow CSF. The brainstem, cranial nerves, and the lower portion of the cerebellum may be stretched or compressed.The blockage of CSF flow may also cause a syrinx to form, eventually leading to syringomyelia.

Repeat selected MR image





Findings

Figure 1: Initial CT of the head showed an intraparenchymal bleed in the left frontal subcortical region.
Subsequent MRI showed the bleed to be predominantly isointense on T1-WI (Figure 2) and heterogeneously bright on T2-WI (Figure 3), suggestive of hyperacute to acute stage. Mild perilesional edema is seen with no abnormal adjacent flow voids. Generalized volume loss is also noted. Gradient echo images (Figure 4 and Figure 5) show multiple, patchy areas of hemorrhage in the bilateral superficial, subcortical white matter appearing as areas of susceptibility.
Follow-up MRI shows the intraparenchymal bleed as high-signal on T1-WI (Figure 6) and hyperintense on T2-WI (Figure 7) suggestive of late-subacute nature of bleed.


Diagnosis: Cerebral amyloid disease (angiopathy)


Cerebral amyloid disease is a localized form of amyloidosis characterized by extracellular deposition of ß-amyloid in the brain, and it is not associated with systemic amyloidosis. It is found at autopsy in 33% of 60–70 year olds and the prevalence increases to 75% of people older than 90 years. Cerebral amyloid deposition occurs in three morphologic varieties, with cerebral amyloid angiopathy (CAA) being the most common with deposition of ß-amyloid protein in the media and adventitia of small and medium-sized vessels of the cerebral cortex, subcortex, and leptomeninges. Amyloidoma and diffuse encephalopathic white matter involvement are rare.

Many cases of CAA are asymptomatic. When symptomatic, typical presentations include acute intracranial hemorrhage, symptoms resembling a transient ischemic attack (TIA), or dementia. However, these symptoms are not specific for CAA and are often not readily associated with CAA. With continued aging of the population, CAA will become even more prevalent, making correct characterization of imaging findings important.

The deposition of ß-amyloid in the vessel wall is associated with fibrinoid necrosis, focal vessel wall fragmentation, and microaneurysms, which all predispose the patient to repeated episodes of blood vessel leakage or frank hemorrhage. Luminal narrowing may occur at sites of fibrinoid necrosis, which can lead to ischemic change. Histologically, ß-amyloid deposits stained with Congo red show classic yellow-green birefringence under polarized light.

Nonenhanced head CT is the preferred initial imaging modality as it provides crucial information regarding the characteristics of the intracranial hemorrhage, including size, location, shape, and extension to the extra axial spaces. MRI is best suited for identification of small or chronic cortical hemorrhages and ischemic sequalae of this disease, exclusion of other causes of acute cortical-subcortical hemorrhage, and assessment of disease progression. GRE is currently the most sensitive MR imaging sequence for detection of the chronic cortical-subcortical microhemorrhages. Local magnetic field inhomogeneity related to the presence of hemosiderin causes a marked loss of signal on T2*-weighted GRE imaging.

CAA-related ICH represents only 2% of all ICH but is an important cause of hemorrhage in normotensive elderly patients without trauma, representing 38% to 74% of ICH cases in the elderly. CAA-related ICH exhibits a distinctive cortical-subcortical distribution that generally spares the deep white matter, basal ganglia, and brainstem. Angiography does not play a role in the evaluation of CAA.

CAA should be considered in the broad differential diagnosis of leukoencephalopathy, especially if associated with cortical-subcortical hemorrhage(s) or progressive dementia. In CAA, atrophy is most likely the result of chronic small vessel ischemia related to ß-amyloid deposition and is usually seen in association with leukoencephalopathy.

There is no current treatment to halt or reverse ß-amyloid deposition. Patients with CAA have an increased risk of bleeding while taking warfarin, even when the level of anticoagulation is in the therapeutic range. The risk-benefit ratio of anticoagulation and thrombolytic therapy in CAA patients should be carefully considered on an individual basis.

Spinal Cord Astrocytoma-MRI

Intramedullary Cord Tumours

Ependymoma-The most common intrinsic spinal cord tumor has a male predilection and a fourth-decade prevalence. They occur anywhere in the cord and are commonly in the conus medullaris, where an exophytic component may be present. They rarely change growth characteristics and metastasize. Lesions are characteristically hypovascular, well circumscribed, and noninfiltrative of the surrounding cord. Symptoms are due to compression of the surrounding cord rather than infiltration. Complete resection often results in prolonged survival.

Astrocytoma These lesions are more common in children than in adults. Sometimes they are associated with microcysts or syrinxes. The pilocytic varieties are well differentiated and tend to be indolent, with a definable surgical plane. Fortunately, anaplastic astrocytoma or glioblastoma are rare. Surgical therapy does not improve the dismal course, with death usually occurring within 2 years
Case by Teleradiology Providers

Details reading in Emedicine article

Olivopontocerebellar degeneration

Findings

Figure 1, Figure 2 and Figure 3: Axial T2 images exhibit reduced brainstem and cerebellar volume, and enlargement of the 4th ventricle and perimesencephalic cistern. Note the normal appearance of the supratentorial brain (Figure 3).
Figure 4 and Figure 5: Sagittal T1 images demonstrate reduced brainstem and cerebellar volume, flattening of the pons, a narrow middle cerebellar peduncle, and enlargement of the 4th ventricle.


Diagnosis: Olivopontocerebellar degeneration


Olivopontocerebellar degeneration (OPCD), once known as Dejerine-Thomas syndrome, is a neurodegenerative disorder caused by progressive infratentorial neuronal loss. The clinical presentation is variable; however, certain features predominate: parkinsonism, pyramidal dysfunction, autonomic dysfunction, and cerebellar ataxia. There is significant overlap with other neurodegenerative disorders including Shy-Drager syndrome, progressive supranuclear palsy, and striatonigral degeneration. These disorders sometimes being referred to as the “Parkinson Plus” syndromes.

Differentiation from Parkinson disease can be extremely difficult with clinical findings alone. It is also important to exclude other causes of progressive neurological decline, such as malignancy, multiple sclerosis, or cerebrovascular disease. Accurate diagnosis is crucial for purposes of patient management, prognosis, and genetic counseling.

The imaging findings of OPCD include pronounced degenerative changes throughout the brainstem and cerebellum as evidenced by flattening of the pons, reduced volume of the medullary olives and middle cerebellar peduncle, and enlargement of CSF spaces including the fourth ventricle and perimesencephalic cistern. This atrophy should be disproportionate to that found throughout the remainder of the brain. Occasionally, demyelination of the transverse pontine fibers may result in a cruciform shaped region of hyperintensity on T2WI, irreverently termed the “Hot Cross Bun” sign.

Evaluation of the middle cerebellar peduncle width is helpful in confirming the diagnosis of OPCD. A measurement of less than 8mm in the sagittal plane has been shown to be both highly sensitive and specific for the disease. Not necessary for diagnosis, but of potential academic interest- these patients will generally demonstrate reduced FDG metabolism on PET and depressed NAA/Cr ratios on MR spectroscopy in the affected areas.

Radiology Grand Rounds-XV

Here is a case of An Unusual Pleural Tumour for the Radiology Grand Rounds submitted by Dr MGK Murthy of Teleradiology Providers. Concept of the Radiology Grand Rounds is available at- Radiology Grand Rounds.

An Unusual Pleural tumour. Dr Jaya, NMC Sky Imaging center, LLRM Medical College, Meerut, Dr(col) M G K Murthy,Dr Sumer Sethi.
Teleradiology Providers http://teleradproviders.com/



INTRODUCTION:

Many neoplastic tumors exhibit paraneoplastic syndromes manifested by endocrinopathy. This is particularly true of intrathoracic tumors such as lung cancers, thymomas, carcinoid tumors and mediastinal germ cell neoplasms. Solitary fibrous tumors (SFT) of the pleura are rare tumors with unpredictable clinical behavior. SFTs of the pleura previously reported as ‘localized benign mesotheliomas’ have been known to be associated with symptomatic hypoglycemia.1 Localized fibrous mesolitheliomas have been known by other names such as solitary mesotheliomas, submesothelial fibromas and pleural fibromas2; due to controversial nature of origin of the tumor. To evade the discussion about histogenesis, the name ‘solitary fibrous tumor’ is used 2,3.

CASE REPORT:
A 56-year normotensive, nonsmoker male presented with recurrent syncopal attacks, light-headedness and generalized weakness, usually upon awakening or about 4-5 hours after his last meal. He had no history of cough, breathlessness or chest pain. Clinical examination revealed grade 1 clubbing. Chest examination revealed dullness to percussion with decreased breath sounds over the lower half of right hemithorax. Post Prandial Blood sugar level was 75 mg %, C-peptide level was 0.71 mg%; serum insulin level was 4.11mIU/ml (normal fasting level 5-20mIU/ml). Chest X-ray showed a large homogeneous opacity occupying the mid and lower zones of right hemithorax. Right lower lobe showed evidence of collapse and rest of the lungfields didi not show any abnormality. Ultrasound examination showed a well defined rounded mixed echogenic mass in the lower half of right hemithorax above the dome of right hemidiaphragm with minimal right pleural effusion. Subsequent CT examination revealed a large mildly enhancing right pleural mass of solid consistencey with a few areas of hypodense nonenhancing regions suggestive of necrosis. CT value ranged from 20 to 60 HU. No evidence of ribdestruction/brochus cutoff or any mediastinal lymphadenopathy demonstrated. No calcification was seen. Minimal pleural effusion was suggested. Lower lobe all segments showed evidence of collapse. Rest of the lung fields showed no significant abnormality. Radiologically a primary pleural based neoplasm was suggested possibly mesothelioma. FNAC was inconclusive. Metastatic workup showed no abnormality.
Right posterolateral thoracotomy was performed. A large lobulated mass, occupying the posterior and inferior portions of the lower half of right hemithorax was present. The tumor was found to originate from the visceral pleura in the right supradiaphragmatic location. There were no attachments of the tumor to the lung, chest wall or diaphragm. The resected mass measured 19x12x11cm and weighed 4 kilograms. Cut section of the mass showed nodular pattern with large whorled white areas. Histopathological examination showed extensive collagen formation and spindle-like cells with rare mitosis. The spindle cells were arranged in single file pattern, ill defined fasicle with myxoid change and in “patternless pattern”. These findings were consistent with the diagnosis of solitary fibrous tumor of pleura. The postoperative course was uneventful. Blood sugar levels returned to normal after surgery.
DISCUSSION-
The First SFT was described by Wagner4 in his article “Das Tuberkelahnliche Lymphadenom.” In 1931, Klemperer and Rabin5 discovered a diffuse type of tumor that arose from the mesothelial layer from a localized form that arose from the submesothelial connective tissue. In 1952 Clagett et al6 used the term localized fibrous mesothelioma to distinguish these usually benign tumors from the more common asbestos related, malignant mesothelioma. Solitary fibrous tumors (SFTs) represent less than 5% of all neoplasms involving the pleura. SFTs are spindle cell neoplasms. They are usually benign, but may be malignant. In the thorax, they usually involve the pleura, but can be intrapulmonary or mediastinal. Histologically, they show a variety of arrangements, from a “patternless pattern” to a hemangiopericytoma-like or diffuse sclerosing appearance, and stain positive for CD34 and vimentin 7.
Most solitary fibrous pleural tumors cause minimal symptoms despite growth to huge proportions8. When present, the most common symptoms are cough, chest pain, dyspnea and pulmonary osteoarthropathy. Hypoglycemia is rare 9,10. Rarely fibrous pleural tumors are malignant and recur locally or at a metastatic site. Most neoplasms associated with hypoglycemia are pancreatic β-cell tumors. Doege11 reported the first patient with an intrathoracic fibrous tumor associated with hypoglycemia in 1930 (Doege Potter syndrome). In 1981, Briselli reviewed 360 cases of solitary pleural fibrous tumors reported since 1942. Four percent had symptomatic hypoglycemia12; one instance of hypoglycemic coma was fatal 13.
Several mechanisms for hypoglycemia associated with solitary fibrous tumors have been proposed; these include secretion of insulin-like growth factor II (IGF-II or big IGF-II), increased utilization of glucose by the huge tumor, insulin receptor proliferation mediated by the solitary fibrous tumor, decreased gluconeogenesis, and decrease ineffective glucagon secretion. Secretion of IGF by the tumor is the most widely accepted mechanism for hypoglycemia in fibrous masses14, 15. The finding of increased IGF-II with hypoglycemia before resection and decreased IGF-II with abatement of hypoglycemia after resection16, supports this hypothesis.
Our patient had hypoinsulinemic hypoglycemia. After resection the blood sugar and the insulin levels returned to normal. There is an overexpression of IGF II, which is responsible for hypoglycemia in solitary fibrous tumors 17.
In conclusion when confronted with a patient with hypoglycemia and suppressed insulin levels, non-islet cell hypoglycemia should be considered. The case reported here demonstrated that a solitary fibrous pleural tumor should be considered in the differential diagnosis. This case is reported in view of its extreme rarity.

Polymicrogyria

Findings

Figure 1, Figure 2, and Figure 3: CT scans of the brain reveal macrocephaly with an abnormal gyral and sulcal pattern.
Figure 4, Figure 5, and Figure 6: Multiple axial T2 MR images reveal macrocephaly and polymicrogyria. There are excessive small convolutions of the cortex with an undulating cortical pattern. The white matter signal is increased, consistent with immature myelination. Note the right parietal shunt catheter with normal ventricular size.
Figure 7, Figure 8, and Figure 9 : There is loss of normal gyral architecture, thickened cortex (isointense to gray matter) and indistinct gray-white interface. This pattern is diffuse and is present throughout the brain.


Diagnosis: Polymicrogyria


Polymicrogyria is a disorder of late neuronal migration and cortical organization. The neurons migrate to the cortex but distribute abnormally resulting in the formation of multiple small undulating gyri. This is believed to result secondary to ischemic laminar necrosis of the fifth cortical layer after 20 weeks gestation at which time the cortical neurons have migrated to the brain surface. Other intrauterine vascular insults or infections, including CMV, may also result in this disorder. Multiple gene loci have been shown to result in polymicrogyria as well.

The result of this late neuronal migration disorder is an excessive number of small disorganized cortical convolutions with a thickened cortex. The white matter thickness is usually normal. CT findings consist of excessive small convolutions. These small folds of cortex may resemble pachygyria (incomplete lissencephaly) which results in sparse, broad, flat gyri. In order to best characterize the cortex, MRI is usually performed. Findings on T1 weighted imaging include irregular cortex isointense to gray matter with an indistinct cortical white matter surface. On T2 weighted imaging, two imaging patterns may be present depending on the age of the patient. In infants under 12 months, T2 weighted imaging reveals small, fine undulating cortex with normal 3-4mm thickness. In infants older than 18 months, the cortex is thick and bumpy (6-8 mm) and may contain hypomyelination and cortical infolding. Periventricular calcification may be present if the disorder is caused by TORCH infection, such as CMV.

Polymicrogyria may be regional or diffuse. Congenital bilateral perisylvian syndrome is the most common manifestation of polymicrogyria. This results in polymicrogyria of the opercular cortex with abnormal sylvian fissure sulcation. Polymicrogyria is present in multiple syndromes, including Zelleweger syndrome and Fukuyama muscular dystrophy. These syndromes contain polymicrogyria as well as other clinical and laboratory findings.

The diagnosis of polymicrogyria is descriptive and does not describe the underlying etiology. Clinically, patients may present in the neonatal period or later in infancy with developmental delay, spasticity, seizures and global developmental delay that may result in feeding difficulties, respiratory abnormalities, motor dysfunction and mental retardation.

Intraventricular Meningioma-MRI

An intraventricular location is relatively rare, accounting for only 2 % of meningiomas, with 80% of these in the lateral ventricles. Despite this, intraventricular meningioma is the most common trigonal mass in the adult. They are thought to form via the infolding of meningeal tissue during the formation of the choroid plexus. Nonenhanced CT typically demonstrates an iso- to hyperdense lesion. Calcification is seen in 20% of cases, with a psammomatous pattern (diffuse, sand-like appearance) most common. Circular, globular, or radial calcification may also be seen. On MRI, lesions are typically hypo- to isointense on T1-weighted images and iso- to hyperintense on T2-weighted images. Lesions classically show intense uniform enhancement on both CT and MR images after injection of contrast media due to their lack of blood-brain barrier.

Ameloblastoma

Findings

CT images demonstrate an expansile cystic “bubbly” mass within the right mandibular body and extending into the ramus. Thin bony septations are seen within the lesion (Figure 1 and Figure 2). Marked thinning of the cortical margins is noted with focal areas of dehiscence (Figure 3). The margins are relatively well-defined with no significant infiltration of adjacent soft tissues. The tongue and medial soft tissue structures are displaced and pushed by this large soft tissue mass in the mandible (Figure 4).
Ill-defined enhancement is seen in the anteromedial aspect of the mass on postcontrast CT (Figure 5).


Diagnosis: Ameloblastoma


Ameloblastoma is a histologically benign, locally aggressive tumor arising from the odontogenic ectoderm. It arises from the enamel-forming cells of the odontogenic epithelium that have failed to regress during embryonic development. Ameloblastoma is the most common odontogenic tumor (representing 10% of all tumors in the maxillomandibular region).

The tumor most commonly occurs in the posterior mandible, typically in the third molar region, with associated follicular cysts or impacted teeth. The mandible is affected four times more frequently than the maxilla. Patients typically present in the third to fifth decades of life with a slow-growing, painless mass.

Ameloblastoma typically presents as a mixed cystic-solid mass in the posterior mandibular ramus associated with an unerupted 3rd molar tooth. The expansile, radiolucent tumor can be unilocular (20%) or multilocular (80%), with a characteristic "soap bubble–like" appearance. The slow growth of the tumor can lead to significant expansion of the mandible with an osseous shell that represents involved bone. The tumor can perforate the lingual cortex and spread to adjacent soft tissues. Erosion of the roots of adjacent teeth is unique to ameloblastoma and indicates aggressive behavior of the tumor.

MRI best defines the extra osseous extension and shows the multilocularity, mixed solid and cystic components, irregularly thickened walls, papillary projections, and marked enhancement of the walls and septa. Presence of nodular enhancement distinguishes ameloblastoma from large dentigerous cyst and odontogenic keratocyst.

The treatment of ameloblastoma is surgical excision with wide free margins. Appropriate reconstruction may be performed at the same time. Solid lesions show high recurrence rates (50% to 90%), necessitating tumor excision or partial resection of the jawbone. Although malignant transformation is rare (1%), repeated recurrences increase the likelihood of malignancy.

Craniopharyngioma-MRI

Craniopharyngioma is a histologically benign, extra-axial, slow-growing tumor that predominately involves the sella and suprasellar space. Craniopharyngiomas are dysodontogenic epithelial tumors derived from the Rathke cleft, which is the embryonal precursor to the adenohypophysis. Changes in signal intensity vary on T1-weighted images depending on the cystic contents, which can appear hyperintense if they have a high protein, blood product, and/or cholesterol content.

Case By Dr MGK Murthy, Dr Sumer Sethi, Teleradiology Providers

Patellar Osteomyelitis-A Rare Case Report

The patella is a rare site for acute osteomyelitis. Most cases are children between 5-15 years of age. The process of patellar ossification might explain this age predilection. The patella is a cartilaginous structure until 4 years of age. The ossification begins at 4 years of age and is complete by 16 years. The rarity of the patellar infection may be explained by the nature of its blood supply and anatomy. The rich blood supply, and absence of epiphyseal plate with its associated sluggish hemodynamics, makes hematogenous osteomyelitis of patella a rarity. Staphylococcus aureus remains the most common cause of osteomyelitis followed by Streptococcus pyogenes, Other rare causes of acute osteomyelitis of patella include Pseudomonas aeruginosa. Related article-- Int Pediatr. 2001;16(4):232-234.

Case by Dr MGK Murthy (Teleradiology Providers), Dr Nageswar Goud and Dr David Kiran

Spinal Haemangioblastoma

Here is a case of Spinal haemangioblastoma submitted by Dr MGK Murthy, Sr Consultant Teleradiology Providers.

Upcoming Radiology Conference information

Sultan Qaboos University and Hospital, Muscat, Sultanate of OMAN are holding an international MRI conference in Feburary 2008 in Muscat,Oman. Kindly see website http://www.radconoman.googlepages.com/ for more information..Their guest faculty includes Prof Ann Osborn etc. Oman is just two hours by air from India.

Methanol intoxication

Findings

Figure 1: Unenhanced CT of the head demonstrates acute hemorrhage within the left caudate nucleus as well as layering in the left lateral ventricle.
Figure 2: There is diffuse edema with effacement of the sulci, white matter lucency, and punctate hemorrhage of the putamina.

Differential diagnosis (Acute)
- Toxic: Methanol intoxication, Carbon monoxide, Cyanide, Hydrogen sulfide
- Hypertensive intracranial hemorrhage
- Hypoxia
- Hypoglycemia
- Hemolytic-uremic syndrome

Differential diagnosis (Chronic)
- Mitochondrial encephalopathies (Leigh’s disease, MELAS, Kearns-Sayre, etc.)
- Leukodystrophy
- Wilson disease


Diagnosis: Methanol intoxication


Methanol is commonly found in household products such as windshield wiper fluid, paint remover, and antifreeze. It is an uncommon but potentially fatal cause of toxicity, and a high clinical suspicion must exist. Symptoms of visual disturbance (blurriness, blindness), headache, nausea, dizziness and confusion may present 12 to 24 hours after consumption. The symptomatic delay is due to the time it takes the liver to metabolize methanol. The gastrointestinal tract rapidly absorbs methanol. It is converted by alcohol dehydrogenase to formaldehyde. The formaldehyde is then converted to the toxic metabolite formic acid by aldehyde dehydrogenase. Formic acid and the resulting metabolic acidosis are thought to contribute to the intracranial findings of cerebral edema, putaminal necrosis, and potential basal ganglia hemorrhage. The basal ganglia have a high metabolic demand and a rich vascular supply, which are thought to be more susceptible to toxic metabolites and hypoxia.

Management and prognosis are based on the resulting metabolic acidosis. Intravenous fomepizole is administered to competitively inhibit alcohol dehydrogenase. This is preferred over the traditional administration of intoxicating intravenous ethanol. Further treatment includes hemodialysis to remove unmetabolized methanol and sodium bicarbonate to treat the metabolic acidosis. Patient prognosis is poor in the setting of basal ganglia hemorrhage. Unfortunately, despite optimal treatment, our patient expired within four days of consuming nearly half-a-gallon of windshield wiper fluid.

Chondroblastoma-MR appearance

Case submitted by Dr MGK Murthy, Sr Consultant Teleradiology Providers