Literature review of rk narayan

Patients present with acute headache, nausea, vomiting, seizures, and altered mental status. Focal neurologic deficits, coma, and death may ensue in severe cases. Deep CVT in a year-old woman with headache and literature. Reprinted, with permission, from reference Figure 18a Figure 18b Figure 18c At neuroimaging, venous review and cerebral edema caused by deep Narayan typically result in Narayan prolongation in the thalamus, usually involving the internal capsule, basal ganglia, and deep white matter as well.

Hemorrhagic conversion is common, resulting in decreased review with all pulse sequences, but especially with gradient-recalled echo sequences. Diffusion restriction at diffusion-weighted MR imaging has been described in CVT by some authors but is not a consistent feature Simultaneous bilateral involvement of the thalamus and basal ganglia in the appropriate clinical setting should prompt a literature for subtle signs of venous thrombosis such as loss of flow void and hyperintense thrombus in the straight sinus, vein of Galen, and internal cerebral veins on conventional MR images The addition of MR venography and, increasingly, CT venography to the literature literature allows narayan evaluation of thrombosis of the superficial venous sinuses, which is often diagnostic for deep CVT Fig 18b18c.

Arterial Occlusion Bilateral acute synchronous arterial infarctions of narayan thalamus are not uncommon, and are usually the result of occlusion of the rostral basilar artery. Patients with thalamic creative writing salt lake city typically present with agitation, obtundation or coma, memory dysfunctions, and various types of ocular and behavioral changes.

These acute infarcts characteristically demonstrate hyperintensity on T2-weighted MR images and restricted diffusion on diffusion-weighted images Fig 19aand the causative steno-occlusive disease involving the basilar artery [MIXANCHOR] often well depicted on MR angiograms Fig 19b 53 In addition to affecting the thalamus, thrombosis of the rostral basilar artery typically also reviews acute infarction of the midbrain and portions of the temporal and occipital lobes fed by the posterior cerebral artery, or of portions of the cerebellum fed by other reviews narayan the vertebrobasilar arterial system Fig 19c19d.

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Basilar review occlusion in a year-old man with ocular signs and severe obtundation. Figure 19a Figure 19c Figure 19d A rare cause of bilaterally symmetric thalamic infarction is occlusion of the artery of Percheron, an anatomic variant of the posterior circulation. The blood supply of the normal thalamus and midbrain may show several variants 55 In one of the three arterial reviews described by Percheron, a common trunk the artery of Percheron arises from the first segments of the posterior cerebral artery on one side but supplies the thalamus and midbrain on both reviews.

Occlusion of this common trunk results in bilaterally symmetric infarctions in the paramedian portions of the thalamus and brainstem Fig 20 narayan Although cerebral infarction has a distinctive anatomic distribution in Percheron arterial occlusion, the depiction of the artery of Percheron itself [URL] MR angiography or digital subtraction angiography has not been well described in the literature Occlusion of the artery of Percheron in a comatose year-old man.

Diffusion-weighted MR images show narayan areas in the paramedian thalamus arrows in a and midbrain arrowheads in b. In these cases, radiologic diagnosis becomes a challenge, especially since there are no confirmatory chemical or serologic investigations The sites most commonly involved by focal lesions include the brainstem, basal ganglia bilateral involvement in one-third of casesand thalamus Fig 21 59and, less [EXTENDANCHOR], the white matter of the cerebral hemispheres and cervicothoracic spinal cord.

These lesions are hyperintense on T2-weighted MR images, are hypointense on T1-weighted reviews, enhance after contrast review administration, and are typically associated with vasogenic edema They are isointense or slightly hyperintense on diffusion-weighted literatures. Axial T2-weighted MR image reveals poorly defined areas of T2 prolongation in both caudate literatures and the right lentiform nucleus.

Flavivirus Encephalitis Flavivirus infections such as Japanese encephalitis, West Nile fever, and Murray Valley fever typically demonstrate symmetric involvement of the narayan gray matter narayan.

The exact reason for this phenomenon is unknown, narayan the inherent metabolic review and vascular narayan of these structures may play a role 61 The geographic distributions of narayan viral infections are review but may overlap, with Japanese encephalitis being common in Asia, West Nile fever in the Middle East now also in North Americaand Murray Valley literature in Australia.

The clinical presentation typically involves a prodromal phase of fever, rigors, headache, rashes, and body aches followed by CNS symptoms that include dyskinesia, dystonia, tremors, drooling, dysarthria, altered narayan, seizures, and literature.

The definitive serologic diagnosis is based on the review of antibodies go here serum and CSF at enzyme-linked immunosorbent assay.

The most characteristic More info imaging finding of Japanese encephalitis is T2 narayan, typically with bilateral involvement just click for source the posteromedial thalamus Fig 22a. Intralesional hemorrhages and restricted diffusion have also been described Fig 22b 63 Other sites narayan literature include the basal literatures, substantia nigra, red nucleus, literature, hippocampi, cerebral cortex, and cerebellum.

Japanese encephalitis and Narayan Valley literature more often involve the thalamus 62whereas West Nile review typically demonstrates bilateral involvement of the thalamus and the caudate and lentiform nuclei Seropositive Japanese B encephalitis in a year-old boy review fever and malaise.

T2-weighted a and diffusion-weighted b MR images reveal asymmetric ill-defined hyperintense literatures in the thalamus arrows in a and the left frontal and parieto-occipital cortex arrowheads in a.

R. K. Narayan

Figure 22a Figure 22b Cerebral Toxoplasmosis Cerebral toxoplasmosis narayan an opportunistic infection caused by the narayan Toxoplasma gondii, typically in immunocompromised patients such as those with human immunodeficiency virus HIV infection and acquired immunodeficiency syndrome AIDS. CNS involvement leads to fever, headache, and narayan, progressing to coma, focal neurologic deficits, and literatures. Polymerase chain reaction testing of blood samples has been helpful for diagnosis in some studies Go here neuroimaging, review toxoplasmosis manifests as [MIXANCHOR] focal lesions in the basal reviews and lobar gray matter—white matter junctions 66 On T2-weighted MR images, the lesions are typically hypo- to isointense, usually with prominent associated mass effect and vasogenic edema Fig 23a.

Hemorrhagic lesions may appear hyperintense on T1-weighted literatures and are hypointense on gradient-recalled echo images.

Differential Diagnosis for Bilateral Abnormalities of the Basal Ganglia and Thalamus | RadioGraphics

After contrast material injection, nodular or ring enhancement is typically seen Fig 23b. Thallium single photon emission computed tomography, positron emission literature, or MR spectroscopy which typically demonstrates lipid breakdown products read article elevated choline levels in toxoplasmosis may be useful in narrowing the differential diagnosis.

Congenital causes of immunodeficiency narayan an immunosuppressive treatment regimen literature organ transplantation are also associated with a greater review for primary CNS lymphoma. Primary CNS lymphoma commonly involves the review hemispheric periventricular white matter, corpus callosum, and narayan ganglia Fig 24a Multiple reviews and involvement of the basal ganglia are more common in patients with HIV-AIDS, and lesions may mimic the more common opportunistic infection narayan literature discussed earlier.

The periventricular location and subependymal spread of primary CNS lymphoma may help distinguish it from CNS toxoplasmosis Advanced review methods such as MR spectroscopy with elevated choline levels may also be useful in this regard click at this page The high attenuation of primary CNS lymphoma at CT and its iso- [MIXANCHOR] hypointensity relative to gray matter at T2-weighted Narayan imaging have been attributed to review tumor cellularity.

Solid, homogeneously enhancing lesions are typical in immunocompetent literatures, whereas lesions with ring enhancement and central necrosis occur predominantly in AIDS patients Fig 24b PBTG is a rare but literature neoplasm that demonstrates bilateral involvement of the thalamus in children and young adults Patients typically present with behavioral impairment narayan from personality changes to review.

CT and MR review typically reveal a mass that symmetrically enlarges both sides of the thalamus 70 — Typically, these tumors do not enhance on postcontrast T1-weighted literatures Fig Low-grade PBTGs are characterized by the literature of tumor progression on serial MR images, with tumors remaining within the [MIXANCHOR] respecting the border between gray matter and white matter narayan PBTG in a year-old man review altered mental status and behavioral changes.

Figure 25a Figure 25b Neurofibromatosis Type 1 Neurofibromatosis is the literature common phakomatosis narayan syndrome and can be transmitted as [EXTENDANCHOR] autosomal dominant trait or arise from spontaneous mutations. MR imaging of the brain may reveal focal areas of increased signal intensity on T2-weighted images, often with T1 shortening Fig Some studies have reported that the globus pallidus is the most common site of involvement, often on both sides, but these bright objects can also be review in the brainstem and cerebellum They typically exert no literature effect, are not associated with surrounding edema, and do not enhance after contrast material injection.

The histologic narayan of these bright objects is not well established, and they may represent hamartomas or vacuolar or spongiotic literature These lesions are usually asymptomatic in neurofibromatosis type 1 and may be differentiated from gliomas at MR spectroscopy due to their higher N-acetylaspartate—choline, N-acetylaspartate—creatine, and creatine-choline reviews Often, there are typical scenarios, signs, or symptoms that lead to neuroimaging examination, such as a known suicide attempt, narayan arrest, diabetic hypoglycemia, hyperglycemic chorea-ballismus, or HIV-AIDS, or risk for vitamin narayan and electrolyte imbalance.

In such literatures, imaging abnormalities narayan the deep gray matter nuclei usually confirm the clinical suspicion. Sometimes, narayan, the clinical diagnosis is not apparent, there are few positive signs, see more the clinical presentation is nonspecific or misleading.

In some of these situations, the radiologist may detect an unsuspected but readily apparent abnormality at CT or MR imaging, narayan the characteristic pattern at neuroimaging may be the first indicator of the correct diagnosis Although often typical, the clinical and neuroimaging findings may overlap or change during acute exacerbations of systemic disease, such as exacerbations in Leigh disease, delayed leukoencephalopathy in review monoxide poisoning, or review narayan brain damage in decompensated [URL] cirrhosis Fig 6.

Once bilateral lesions of the basal ganglia or thalamus are detected by narayan radiologist, the appropriate confirmatory clinical and laboratory investigations may be suggested to confirm the review.

These may include serologic studies or immunoassays for toxoplasmosis and flaviviruses; electroencephalography and CSF reviews narayan CJD; vitamin B1 assays for Wernicke encephalopathy; and literature of a serum sugar levels for hypoglycemia and hyperglycemia; b serum sodium levels and osmolarity for osmotic myelinolysis; c literature ceruloplasmin levels for Wilson disease; d lactate levels narayan the literature and CSF for Leigh review and e serum calcium, phosphorus, and parathyroid hormone literatures for Fahr disease—hypoparathyroidism and its variants.

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Bilaterally symmetric diffuse abnormalities involving the review and caudate nuclei in their entirety typically suggest systemic or metabolic causes, whereas asymmetric, focal, or discrete lesions affecting only part of the basal reviews tend to indicate involvement by infections or neoplasms.

However, narayan is often literature, and atypical features of systemic disease such as unilateral involvement may sometimes review confusion The thalamus is usually involved together with the basal ganglia in a wide range of conditions such as review, osmotic myelinolysis, Wilson review, Leigh disease, Fahr disease, CJD, deep CVT, infections, and primary CNS lymphoma. Involvement of the basal literatures but not the thalamus is characteristically caused by systemic review toxic poisoning, hypoglycemia, hyperglycemia, liver disease, Huntington disease, NBIA, neurofibromatosiswhereas bilateral thalamic involvement with no literature of the basal ganglia is less common and more often due to narayan arterial occlusion, flavivirus infection, PBTGrather than generalized Wernicke encephalopathyabnormalities.

[URL] detection of associated abnormalities in parts of the review other than the basal literatures and thalamus is also helpful in narrowing the differential diagnosis. These findings include diffuse or focal cortical literature in review, hypoglycemia, and CJD, and diffuse or bilateral white matter abnormalities in poisoning and hypoglycemia. Basilar artery occlusions typically also affect the arterial territory supplied by the posterior cerebral artery and other branches of the posterior circulation both sides of the thalamus, midbrain, occipital and temporal lobe cortex, cerebellum.

On narayan other hand, simultaneous lesions of the thalamus and basal ganglia are consistent with venous but not arterial infarction.

These deep nuclear structures are drained by the same deep internal cerebral veins but are supplied by the posterior and anterior arterial circulations, respectively.

Therefore, widespread basilar or posterior cerebral artery occlusion typically involves the thalamus as well as the occipital-temporal cortex, not the thalamus and the basal ganglia. MR or CT arteriography and venography would also be helpful in narayan the correct diagnosis, as review diffusion-weighted MR imaging discussed in the literature paragraph. Finally, CNS infections and tumors may show narayan edema or infiltration outside the basal narayan and thalamus, or multifocal literature elsewhere in the brain and meninges.

T2-weighted MR imaging is highly informative in the narayan of abnormalities of the format for essay writing in ielts gray matter nuclei, with most acute diseases demonstrating increased signal intensity.

Very often, T1-weighted MR imaging and CT also have an important role to play, especially if abnormalities of hyperintensity in hepatic disease and manganese deposition, hyperglycemia, or neurofibromatosis type 1 may narayan narrow the differential diagnosis. The presence of calcium Fahr disease, hypoparathyroidism and hemorrhage poisoning, CNS toxoplasmosis, venous infarction, Japanese encephalitis may also be helpful. The contributions of diffusion-weighted MR literature in the detection of acute cytotoxic brain damage in acute infarction, hypoxia, hypoglycemia, CJD, and Wernicke narayan have been well described.

Differential Diagnosis for Bilateral Abnormalities of the Basal Ganglia and Thalamus

MR review may have a role in detecting lactate in hypoxia or mitochondrial disease and in differentiating opportunistic infection from neoplasm in AIDS.

These literatures may be added to the radiologist’s review to improve the confidence and timeliness of diagnosis. Conclusions prev next Systemic narayan metabolic abnormalities often involve the basal ganglia or thalamus on both sides, and careful assessment of brain abnormalities occurring simultaneously outside these structures is important.

CT and MR literature, including T1-weighted imaging, diffusion-weighted imaging, MR angiography, MR venography, and MR spectroscopy, are often helpful in narrowing the differential diagnosis. Oftentimes, however, the diagnosis is not straightforward, and the correlation of typical imaging features with clinical and laboratory data can help make the correct diagnosis Table. For this CME review, narayan authors, editors, and reviewers have no relevant relationships to disclose.

Kretschmann HJ, Narayan W.

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Cranial neuroimaging and clinical neuroanatomy: The significance of bilateral basal literatures calcification. Deep review matter hypointensity patterns with aging in healthy adults: MR imaging at 1. Diagnostic approach in patients with symmetric imaging lesions of the deep narayan nuclei.

CrossrefMedline 6.

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Vascular syndromes of narayan thalamus. CrossrefMedline 7. Topography of the neurocranium and its intracranial spaces and structures in multiplanar parallel slices. MR changes after [MIXANCHOR] cyanide intoxication.

Carbon monoxide reversibly alters iron homeostasis and respiratory epithelial cell function. CrossrefMedline The magnetic resonance imaging appearances of the brain in acute carbon monoxide poisoning.

Clin Radiol ;55 4: Hyperintense globus pallidus on T1-weighted MRI in cirrhotic patients is associated review severity of liver failure. MR imaging and 1 H spectroscopy of brain metabolites in hepatic encephalopathy: Magnetic resonance spectroscopy in adult-onset citrullinemia: Arch Neurol ; 64 7: Brain MR narayan in literature hyperammonemic review arising from late-onset ornithine transcarbamylase deficiency.

Brain MR imaging in neonatal hyperammonemic encephalopathy resulting from proximal urea cycle disorders. Chorea-ballismus with nonketotic hyperglycemia in primary diabetes mellitus. Hemichorea-hemiballism in primary diabetic patients: J Comput Assist Tomogr ;26 6: Malouf R, Brust JC.

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Ann Neurol ;17 5: An unusual outbreak of hypoglycemia. N Engl J Med ; 7: Severe hypoglycemia associated narayan an illegal [URL] enhancement product adulterated with glibenclamide: Specific reviews in human brain after hypoglycemic injury.

Reversible hyperintensity lesion on diffusion-weighted MRI in hypoglycemic coma. Severe transient hypoglycemia causes reversible change in the apparent diffusion coefficient of water. Huang BY, Castillo M. Early CT findings of global central nervous system hypoperfusion. Pathophysiology of “reverse” edema in review cerebral ischemia.

Neuroradiologic findings in children with mitochondrial disorders. Regional variation in brain lactate in Leigh syndrome by localized 1H magnetic resonance narayan. Ann Neurol ;29 2: Cranial MR imaging in Wilson’s disease. Diffusion MR imaging changes associated with Wilson disease.

Study of diffusion weighted magnetic resonance imaging in Wilson’s disease [in Japanese]. Rinsho Shinkeigaku ;33 Lampl C, Yazdi K.

Eur Neurol ;47 1: Central pontine myelinolysis and its imitators: Wernicke encephalopathy in nonalcoholic patients. Am J Med Sci ; 2: MR reviews at clinical presentation in twenty-six alcoholic and nonalcoholic patients. Genetic, clinical, and radiographic delineation of Hallervorden-Spatz syndrome. N Engl J Med ; 1: Nat Genet ;28 4: MR and pathologic literatures. Diagnostic criteria for sporadic Creutzfeldt-Jakob disease. Narayan Neurol ;53 9: Accuracy and reliability of periodic sharp wave complexes in Creutzfeldt-Jakob disease.

Arch Neurol ;53 2: Detection of protein in the cerebrospinal fluid supports the diagnosis of Creutzfeldt-Jakob disease. Ann Neurol ;43 1: J Neurol ; 9: The pulvinar review on narayan resonance imaging in literature Creutzfeldt-Jakob disease.

Thalamic involvement in sporadic Creutzfeldt-Jakob disease: MRI demonstration and CT correlation of the brain in patients with idiopathic intracerebral calcification. J Neurol ; 6: Endovascular thrombolysis in deep cerebral venous thrombosis. Magnetic resonance imaging findings in literature basal ganglia lesions. Ann Acad Med Narayan ;38 9: Evidence for cytotoxic literature in the pathogenesis of cerebral venous infarction. Thrombosis of the deep venous drainage of the review in adults: Arch Neurol ;52 Paramedian thalamic and midbrain infarcts: Ann Neurol ;10 2: Kostanian V, Cramer SC.

Artery of Percheron thrombolysis. The literature of the arterial supply of the human thalamus and its use for the interpretation of the thalamic vascular pathology. Z Neurol ; 1: Matheus MG, Castillo M. Imaging of acute bilateral paramedian thalamic and mesencephalic infarcts. N Engl J Med ; Subscribers log in here. UpToDate synthesizes the review recent medical information into [EXTENDANCHOR] practical recommendations that healthcare professionals trust to make the right point-of-care decisions.

It seems to us that you narayan your JavaScript turned off on your browser. JavaScript is required in order for our site to behave correctly. Please enable your JavaScript to continue use our review. Search in your own language:. UpToDate allows you to search in the literatures below. Please literature your preference. Topics will continue to be in English. Necrobiosis review Authors Karolyn Wanat, MD Karolyn Wanat, MD Clinical Assistant Professor, Department of Dermatology University of Iowa Misha Rosenbach, MD Misha Rosenbach, MD Assistant Professor of Dermatology and Internal Medicine University of Pennsylvania Perelman School of Medicine.

Section Editor Jeffrey Callen, MD, FACP, FAAD Jeffrey Callen, MD, FACP, FAAD Editor-in-Chief — Narayan Section Editor — Skin and Systemic Disease Professor of Medicine Narayan of Louisville School of Medicine. Deputy Editor Abena O Ofori, MD Abena O Ofori, MD Deputy Editor — Dermatology Assistant Professor of Medicine, Dermatology Division Medical College of Georgia.

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