[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"menu":3,"$fhob5mrb6_9zTGsz9Fcy5hJnDUv0w_S2_9sU4cYxWEB0":210},{"main":4,"mainTranslated":17,"footer":45,"footerTranslated":109},[5,8,11,14],{"title":6,"url":7},"Course library","https:\u002F\u002Fwww.medmastery.com\u002Fcourse-library",{"title":9,"url":10},"Pricing","https:\u002F\u002Fwww.medmastery.com\u002Fpricing",{"title":12,"url":13},"Earn credits","https:\u002F\u002Fwww.medmastery.com\u002Fcme-credits",{"title":15,"url":16},"Institutions","https:\u002F\u002Fwww.medmastery.com\u002Finstitutions",{"de":18,"es":27,"fr":36},[19,21,23,25],{"title":20,"url":7},"Kurse",{"title":22,"url":10},"Preise",{"title":24,"url":13},"CME-Punkte",{"title":26,"url":16},"Organisationen",[28,30,32,34],{"title":29,"url":7},"Biblioteca de cursos",{"title":31,"url":10},"Precios",{"title":33,"url":13},"Gana créditos",{"title":35,"url":16},"Instituciones",[37,39,41,43],{"title":38,"url":7},"Cours",{"title":40,"url":10},"Tarifs",{"title":42,"url":13},"Obtenir des crédits",{"title":44,"url":16},"Établissements",[46,59,79,97],{"title":47,"group":48,"menu":49},"Company",true,[50,53,56],{"title":51,"url":52},"Our teachers","https:\u002F\u002Fwww.medmastery.com\u002Fteachers",{"title":54,"url":55},"About us","https:\u002F\u002Fwww.medmastery.com\u002Fabout-us",{"title":57,"url":58},"Work with us","https:\u002F\u002Fwww.medmastery.com\u002Fwork-with-us",{"title":60,"group":48,"menu":61},"Product",[62,64,67,70,73,76,78],{"title":63,"url":7},"Courses",{"title":65,"url":66},"Magazine","https:\u002F\u002Fwww.medmastery.com\u002Fmagazine",{"title":68,"url":69},"Podcast","https:\u002F\u002Fwww.medmastery.com\u002Fpodcasts",{"title":71,"url":72},"Webinars","https:\u002F\u002Fwww.medmastery.com\u002Fwebinars",{"title":74,"url":75},"Guides","https:\u002F\u002Fwww.medmastery.com\u002Fguides",{"title":15,"url":77},"https:\u002F\u002Fwww.medmastery.com\u002Finstitutions\u002F",{"title":9,"url":10},{"title":80,"group":48,"menu":81},"Legal",[82,85,88,91,94],{"title":83,"url":84},"Imprint","https:\u002F\u002Fwww.medmastery.com\u002Fimprint",{"title":86,"url":87},"Newsletter policy","https:\u002F\u002Fwww.medmastery.com\u002Fnewsletter-privacy-policy",{"title":89,"url":90},"Privacy policy","https:\u002F\u002Fwww.medmastery.com\u002Fprivacy-policy",{"title":92,"url":93},"Cookie Policy","https:\u002F\u002Fwww.medmastery.com\u002Fcookie-policy",{"title":95,"url":96},"Terms","https:\u002F\u002Fwww.medmastery.com\u002Fterms",{"title":98,"group":48,"menu":99},"Customer support",[100,103,106],{"title":101,"url":102},"FAQs","https:\u002F\u002Fwww.medmastery.com\u002Ffaqs",{"title":104,"url":105},"Contact","https:\u002F\u002Fwww.medmastery.com\u002Fcontact",{"title":107,"url":108},"support@medmastery.com","mailto:support@medmastery.com",{"de":110,"es":143,"fr":177},[111,118,128,137],{"title":112,"group":48,"menu":113},"Unternehmen",[114,116,117],{"title":115,"url":52},"Unsere Dozentinnen und Dozenten",{"title":54,"url":55},{"title":57,"url":58},{"title":119,"group":48,"menu":120},"Produkt",[121,122,123,124,125,126,127],{"title":20,"url":7},{"title":65,"url":66},{"title":68,"url":69},{"title":71,"url":72},{"title":74,"url":75},{"title":26,"url":77},{"title":22,"url":10},{"title":129,"group":48,"menu":130},"Rechtliches",[131,133,134,135,136],{"title":132,"url":84},"Impressum",{"title":86,"url":87},{"title":89,"url":90},{"title":92,"url":93},{"title":95,"url":96},{"title":138,"group":48,"menu":139},"Kundenservice",[140,141,142],{"title":101,"url":102},{"title":104,"url":105},{"title":107,"url":108},[144,151,162,171],{"title":145,"group":48,"menu":146},"Empresa",[147,149,150],{"title":148,"url":52},"Nuestros profesores",{"title":54,"url":55},{"title":57,"url":58},{"title":152,"group":48,"menu":153},"Producto",[154,156,157,158,159,160,161],{"title":155,"url":7},"Cursos",{"title":65,"url":66},{"title":68,"url":69},{"title":71,"url":72},{"title":74,"url":75},{"title":35,"url":77},{"title":31,"url":10},{"title":163,"group":48,"menu":164},"Información legal",[165,167,168,169,170],{"title":166,"url":84},"Aviso legal",{"title":86,"url":87},{"title":89,"url":90},{"title":92,"url":93},{"title":95,"url":96},{"title":172,"group":48,"menu":173},"Atención al cliente",[174,175,176],{"title":101,"url":102},{"title":104,"url":105},{"title":107,"url":108},[178,185,196,204],{"title":179,"group":48,"menu":180},"Entreprise",[181,183,184],{"title":182,"url":52},"Nos enseignants",{"title":54,"url":55},{"title":57,"url":58},{"title":186,"group":48,"menu":187},"Produit",[188,189,190,191,192,193,194],{"title":38,"url":7},{"title":65,"url":66},{"title":68,"url":69},{"title":71,"url":72},{"title":74,"url":75},{"title":15,"url":77},{"title":195,"url":10},"Tarification",{"title":197,"group":48,"menu":198},"Mentions légales",[199,200,201,202,203],{"title":197,"url":84},{"title":86,"url":87},{"title":89,"url":90},{"title":92,"url":93},{"title":95,"url":96},{"title":205,"group":48,"menu":206},"Service client",[207,208,209],{"title":101,"url":102},{"title":104,"url":105},{"title":107,"url":108},{"content":211,"related":283,"meta":355,"internal":365},{"title":212,"leadIn":213,"category":214,"elements":217,"becomeAnExpert":252,"author":273,"readDuration":281,"readDurationFormatted":282}," Distinguishing common adult extra-axial tumors","In this video, you will learn how to recognize the most common adult extra-axial tumors in the posterior fossa—and avoid misdiagnosis—and why you can't use CT scans alone to do this.",{"id":215,"name":216},1,"Course previews",[218,229,234,239,247],{"type":219,"data":220},"video",{"readDurationInSeconds":221,"video":222},298,{"platform":223,"name":224,"url":225,"size":226},"YouTube","Distinguishing common adult extra-axial tumors on computed tomography (CT) imaging","https:\u002F\u002Fwww.youtube.com\u002Fwatch?v=lFR149a0SAs",{"width":227,"height":228},200,113,{"type":230,"data":231},"free_text",{"readDurationInSeconds":232,"text":233},9.066666666666666,"\u003Cp>In this video, taken from our \u003Ca href=\"https:\u002F\u002Fwww.medmastery.com\u002Fcourse\u002Fbrain-ct-essentials\">Brain CT Essentials\u003C\u002Fa> course, you will learn how to recognize the most common adult extra-axial tumors in the posterior fossa—and avoid misdiagnosis—and why you can't use CT scans alone to do this.\u003C\u002Fp>",{"type":230,"data":235},{"readDurationInSeconds":236,"title":237,"text":238},19.200000000000003,"Join our Brain CT Essentials course now!","\u003Cp>Diagnosing brain pathologies can seem difficult. This course will demystify brain CT for you. You will review basic brain and skull anatomy, and learn how to diagnose common diseases encountered in your daily practice. You’ll learn how to manipulate the image in a way that will greatly improve the quality of your patients' scans. We will also teach you how to recognize common artifacts that may be mistaken for disease, thereby avoiding further unnecessary imaging or therapy.\u003C\u002Fp>",{"type":240,"data":241},"cta",{"readDurationInSeconds":242,"text":243,"buttonText":244,"buttonUrl":245,"teachIllustration":246},3.466666666666667,"Start the first chapter of our Brain CT Essentials course for free","Start chapter 1 now","https:\u002F\u002Fwww.medmastery.com\u002Fuser\u002Fregister?target=%2Fcourses%2Fbrain-ct-essentials","https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F99f55ebf-284c-4117-bd43-97efcf73982c",{"type":230,"data":248},{"readDurationInSeconds":249,"title":250,"text":251},155.46666666666667,"VIdeo transcript","\u003Cp>Magnetic resonance imaging is just better than CT when it comes to demonstration of masses and the posterior fossa. That's because of the artifacts that appear on head CT arising from the dense bones of the skull base, and dental implants or fillings. These artifacts will degrade the imaging frequently in non-intuitive ways.\u003C\u002Fp>\u003Cp>The problem is quite evident in this patient with a known posterior fossa mass. These alternating white and dark lines are due to artifacts arising from the skull base and fillings in the teeth and they obscure the tumor. The three most common adult extra-axial tumors in the posterior fossa, that is the space below the tentorium, are the meningioma, vestibular schwannoma, and epidermoid.\u003C\u002Fp>\u003Cp>Elsewhere on the brain meningioma remains the most common extra-axial tumor. Although you should keep in mind that can be hard to distinguish from metastatic tumors involving the dura or bone in patients with cancer. Arachnoid cysts are not strictly tumors but can have mass effect like solid masses.\u003C\u002Fp>\u003Cp>This magnetic resonance image demonstrates a small vestibular schwannoma. These are histologically benign nerve sheath tumors arising from the eighth cranial nerve. These tend to occur initially within the internal auditory canal as shown here. When they grow larger, they can extend into the adjacent cistern, and compress the brainstem while the tumor is still evident in the internal auditory canal.\u003C\u002Fp>\u003Cp>This patient's magnetic resonance scan demonstrates an extra-axial mass that is largely on the patient's right, but crosses the midline and does not involve the internal auditory canal. These findings argue against the diagnosis of a vestibular schwannoma and this proved to be a meningioma.\u003C\u002Fp>\u003Cp>Keep in mind that all meningiomas and schwannomas enhance on magnetic resonance imaging, but can have cystic areas that do not enhance, This patient has a left sided posterior fossa mass that displaces the middle cerebellar peduncle. This mass did not enhance so meningioma and vestibular schwannomas are not considerations.\u003C\u002Fp>\u003Cp>While the mass resembles cerebrospinal fluid on this MRI image, both arachnoid cysts and epidermoid tumors can resemble fluid on both CT and MR. In this case, the MR diffusion scan established the diagnosis of an epidermoid tumor, since an arachnoid cyst should be dark, and resemble CSF elsewhere on the image.\u003C\u002Fp>\u003Cp>This patient chose a different CP angle mass at the level of the internal auditory canal, seen here on the T1 weighted MR image. But in this case, the mass on this diffusion weighted image has the same signal as CSF in the fourth ventricle. This proved to be an arachnoid cyst, which is simply a collection of cerebrospinal fluid that usually does not require treatment.\u003C\u002Fp>\u003Cp>Usually the combination of CT and MR and the use of intravenous contrast will allow you to correctly predict the nature of posterior fossa extra-axial masses. Consider this patient who presents to the emergency room with dizziness. His CT scan demonstrated a low attenuation mass but poorly seen on the CT scan.\u003C\u002Fp>\u003Cp>But you know it's there by the loss of the fourth ventricular contour. Based on the CT scan alone, this mass could be intra or extra-axial in location. The T1 weighted MR scan of this patient demonstrated that the lesion has a sharp border with the brain. |On the mass appears to be surrounded by brain, you now know to be skeptical of this observation when based on a single view.\u003C\u002Fp>\u003Cp>That's especially true with masses at the periphery of the brain and at the midline. In contrast, enhanced MR imaging have demonstrated that this lesion did not enhance at all. That observation makes meningioma and schwannoma very unlikely, since both usually enhance with intravenous contrast. This midline mass has very high signal intensity on this diffusion weighted MR image.\u003C\u002Fp>\u003Cp>When you consider that the lesion does not enhance, its location in the midline, and it's high signal intensity on diffusion weighted imaging, even though this is not a typical location for it, you can conclude that this tumor is an extra-axial epidermoid. While you will not be able to predict the type of every extra-axial mass, accurate localization of the mass to the extra-axial space will allow you to limit the possibilities considerably.\u003C\u002Fp>",{"courses":253,"showAwardsBelow":48},[254],{"id":255,"isFreeCmeCourse":256,"title":257,"type":258,"specialization":259,"teachers":261,"cmeCredits":263,"teacherIllustration":246,"backgroundImage":264,"relativeUrl":265,"lastChanged":266,"created":267,"description":268,"relativeURL":265,"meta":269},6885,false,"Brain CT Essentials","course",[260],"Imaging",[262],"Alexander Mamourian, MD",5,"https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F99f55ec0-1254-42e2-82e5-6e5a0cf475c5","\u002Fcourses\u002Fbrain-ct-essentials","1771265953","1603753644","Diagnosing brain pathologies can seem difficult. This course will demystify brain CT for you. You will review basic brain and skull anatomy and learn how to diagnose common diseases encountered in your daily practice. You’ll learn how to manipulate the image in a way that will greatly improve the quality of your patients' scans. We will also teach you how to recognize common artifacts that may be mistaken for disease, thereby, avoiding further unnecessary imaging or therapy.",{"duration":270,"quizzes":271,"lessons":272},11149,8,39,{"id":274,"name":262,"image":275,"profession":276,"relativeUrl":279,"specializations":280},6884,"https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F9c43ceff-c546-436e-bc3b-8e0e5da4e897",{"name":277,"description":278},"Radiologist","Alex is a Professor Emeritus of Radiology at the University of Pennsylvania.","\u002Fteachers\u002Falexander-mamourian-md",[260],197,"4m",[284,312,331],{"id":285,"title":286,"text":287,"image":288,"author":296,"path":305,"readDuration":306,"readDurationFormatted":307,"internal":308},1350,"How to Recognize INOCA (ANOCA) on an Exercise Stress Test ","Angina, abnormal stress test, clean coronaries—that's INOCA (or ANOCA), and it carries real risk. Learn to recognize and report it with exercise stress ECG.",{"alt":289,"title":290,"size":291,"location":293},"Illustration of the heart's coronary vasculature showing large coronary arteries and the extensive network of smaller vessels affected in INOCA (ischemia with nonobstructive coronary arteries).","",{"width":292,"height":292},1200,{"bucket":294,"key":295},"public-drupal-medmastery-assets-production","\u002F2026-05\u002FC17(1)_magazine image_0.png",{"id":297,"title":298,"relativeURL":299,"image":300,"professionLong":301,"profession":302,"weight":304},1563,"Franz Wiesbauer, MD MPH","\u002Fteachers\u002Ffranz-wiesbauer-md-mph","https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F9c43cef0-41ee-4005-9e4a-d8711c816401","Franz is the founder and CEO of Medmastery. He is an internist with a specialization in cardiology and a master’s in public health from Johns Hopkins University.",{"name":303},"Internist",4,"\u002Fmagazine\u002Fexercise-stress-ecg-inoca",141,"3m",{"created":309,"updated":310,"published":311},1778115738,1778118425,1778118255,{"id":313,"title":314,"text":315,"image":316,"author":322,"path":324,"readDuration":325,"readDurationFormatted":326,"internal":327},1348,"Hyperlipidemia screening: who, when, & what to measure","Testing for hyperlipidemia can help you mitigate your patients' cardiovascular risk. Learn who to screen and when, which measures to request, and how to stratify risk.",{"alt":317,"title":290,"size":318,"location":320},"Lipid panel blood sample tubes used to test for hyperlipidemia in a laboratory setting",{"width":319,"height":319},600,{"bucket":294,"key":321},"\u002F2026-04\u002FC121_magazine image.png",{"id":297,"title":298,"relativeURL":299,"image":300,"professionLong":301,"profession":323,"weight":304},{"name":303},"\u002Fmagazine\u002Ftest-for-hyperlipidemia",246,"5m",{"created":328,"updated":329,"published":330},1777403036,1777572381,1777412421,{"id":332,"title":333,"text":334,"image":335,"author":340,"path":349,"readDuration":350,"readDurationFormatted":282,"internal":351},1347,"Outpatient care for COPD exacerbations","Most acute COPD exacerbations can be managed with outpatient treatment. Learn how to treat mild and moderate COPD exacerbations—and when to escalate care.",{"alt":336,"title":290,"size":337,"location":338},"Older patient using a handheld nebulizer to inhale bronchodilator medication during an acute COPD exacerbation",{"width":319,"height":319},{"bucket":294,"key":339},"\u002F2026-04\u002FC133(4)_ exacerbations_magazine image.png",{"id":341,"title":342,"relativeURL":343,"image":344,"professionLong":345,"profession":346,"weight":348},5365,"Siamak Moayedi, MD","\u002Fteachers\u002Fsiamak-moayedi-md","https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F9c43cf02-1064-4074-817b-0eb5de6ded74","Professor and Director of Medical Student Education, University of Maryland and Course Director, Essential and Critical Procedures, Emergency Medicine.",{"name":347},"Emergency medicine physician",1533,"\u002Fmagazine\u002Facute-copd-exacerbation-treatment",191,{"created":352,"updated":353,"published":354},1776705362,1776710540,1776710541,{"seo":356,"og":358},{"title":357,"description":213}," Distinguishing common adult extra-axial tumors | Medmastery",{"title":357,"description":213,"image":359},{"alt":290,"title":290,"size":360,"location":363},{"width":361,"height":362},606,364,{"bucket":294,"key":364},"\u002Fmigrated-images\u002F06-distinguishing-common-adult-extra-axial-tumors-brain-ct-essentials-preview.png",{"id":366,"created":367,"updated":368,"published":367},374,1601392040,1655189586]