Brain imaging course – Unknown case 6

Posted on by Brent Weinberg, MD

Brain imaging course – Unknown case 6

This video is the 6th unknown case that goes with the brain imaging capstone course.

If you want to follow along, you can find all the images for the case at the brain capstone website.

Introduction

69 year-old-female with h/o autoimmune hepatitis on immunosuppression, admitted for hyponatremia. Hospital course complicated by vision changes and leukocytosis.

Interactive review – MRI

This MRI includes diffusion weighted imaging (DWI), apparent diffusion coefficient (ADC), FLAIR, T2, T1 pre-contrast, and T1 postcontrast. The FLAIR image shows a lesion which is isointense to gray matter centrally with hyperintense edema around the margin. The T2 has a unique feature which helps point to this diagnosis, which is a relatively T2 dark surrounding rim. On pre-contrast T1, it is dark in the center with a rim of edema which is not too dark. On postcontrast it is enhancing around the periphery with central necrosis.  

On the diffusion images you see a rounded hyperintense structure in the right occipital and parietal lobe. It is extremely bright centrally, and is also quite dark on ADC. This proves that there is low water diffusion in the center of the lesion.

Case summary

This case is summarized by a few key findings: lightbulb bright diffusion, dark ADC, and a central rim of enhancement with central necrosis.

Question 6

How would you describe the restricted diffusion pattern, and what is it concerning for? The pattern is centrally reduced diffusion, which is concerning for pus.

Diagnosis – Cerebral abscess

This is a case of a cerebral abscess, in this case from aspergillus. This patient was immunocompromised and had symptoms of infection. Common symptoms for presentation include seizure, altered mental status, or focal neurologic symptoms. Key imaging features are the central hypodensity on CT, a centrally enhancing region with necrosis centrally, and reduced diffusion in the center. The T2 hypointense rim is a characteristic of abscess which isn’t seen on many other disease.

See all of the brain course videos on the brain course playlist, or go back to the brain capstone course page.

 

Brain imaging course – Unknown case 5

Posted on by Brent Weinberg, MD

Brain imaging course – Unknown case 5

This video is the 5th unknown case that goes with the brain imaging capstone course.

If you want to follow along, you can find all the images for the case at the brain capstone website.

Introduction

51 year-old-female presents with left sided weakness and numbness

Interactive review – CT

This case features a CT with a brain window on the left and a bone window on the right. As you scroll up, you start to note that the right lateral ventricle is a little compressed and there is loss of the normal sulci on the right. If you window it really tightly, you can start to see the outlines of a mass along the parietal convexity. In this case, we want to get an MRI so we can better evaluate it.

Interactive review – MRI

The MRI includes diffusion weighted imaging, FLAIR, T2, and pre- and post-contrast T1 weighted imaging. On diffusion, the mass is faintly hyperintense but pretty homogeneous with compression of the brain away from the mass. Similarly, on FLAIR, the mass is pretty homogeneous and has a large contact with the dura and adjacent calvarium. The T2 is particularly helpful because you see a thin cleft of CSF around the mass (a CSF cleft). You also see a little bit of a radial spoke type pattern radiating out from the calvarium where the bone is abnormal. On pre-contrast T1, the mass is pretty isointense to slightly hypointense to the adjacent gray matter. On postcontrast, you see homogeneous and avid enhancement and again are able to make out the CSF cleft. The coronal postcontrast images confirm the findings you saw on axial imaging

Interactive question 5

Is this lesion intra-axial or extra-axial? It is extra-axial

How do you know? You have a thin CSF cleft, compression of the brain away from the mass, and a thin dural tail.

CT explanation

Some select images from the CT are shown here, where you can see the subtle mass and bony erosion. There are some examples from a CT angiogram showing displacement of the dural vessels away from the mass. An additional representative example shows vessels radiating out from the central portion of the mass.

MRI explanation

Select images from the MRI show key images highlighting the CSF cleft sign, the dural tails, and the avidly enhancing extra-axial mass.

Diagnosis – Meningioma

This is a case of a meningioma. These usually occur in older patients > 40 years old and present with symptoms of brain compression or increased intracranial pressure. Meningiomas range from grade 1-3. The treatment of meningioma is usually surgical resection, sometimes with radiation afterwards. If they are in delicate locations or the patient has health problems making surgery less desirable, you can treat them with radiation alone.

See all of the brain course videos on the brain course playlist, or go back to the brain capstone course page.

 

Imaging appearance of odontogenic lesions on CT

Posted on by Brent Weinberg, MD

Imaging appearance of odontogenic lesions on CT

In this video, Dr. Katie Bailey gives us an overview of odontogenic lesions, or those lesions related to the teeth and their imaging appearance on CT. In this talk, we will review some of the most common odotogenic lesions and their imaging appearance so you are familiar with them when you see them.

Introduction

Odontogenic lesions are lesions of the jaw that are associated with a tooth or a component of a tooth. They are usually above the level of the alveolar canal, unlike non-odontogenic lesions. One common strategy for helping make your differential is to divide them into radiolucent lesions and radiopaque lesions

Infection

If you see an infection of the sinuses, you should take a look at the adjacent teeth. Dental and periodontal disease can affect the sinuses, particularly the adjacent maxillary sinus. When there is a connection between lucency around a tooth which is directly connected with the sinus, it is called an oroantral fistula, and can either cause inflammation of the sinus or lead pus directly into the sinus.

Radicular cyst

Radicular cysts are the most common asymptomatic cysts. They are usually less than 1 cm and are associated with the root of a tooth. They have a well defined margin which is sclerotic and larger than the typical circumferential periapical lucency.

Residual cyst

A residual cyst is a cystic lesion that remains at the site of a previously extracted tooth. It also has a thin rim with a sclerotic margin, but the tooth is absent.

Dentigerous cyst

These are usually seen in younger adults and surround the crown of an unerupted tooth. This is most common with more posterior molars, such as the third molar.

Odontogenic keratocyst

These are usually also associated with unerupted teeth, and are most common seen along the posterior body and ramus of the mandible. They are often well-defined and expansile. On MRI, they often have restricted diffusion with a rim of enhancement

Ameloblastoma

Ameloblastoma is the most common odontogenic tumor. They are benign but locally aggressive. They are radiolucent and can have one or more cysts. They can have cortical breakthrough and a soft tissue component. While they look like odontogenic keratocysts, they are usually NOT associated with a tooth.

Odontoma/Supernumerary teeth

This is a sclerotic lesion which has a toothlike resemblance and occur in the posterior maxilla or mandible. They can also be associated with a tooth or residual tooth.

Cemento-osseous dysplasia

This is a replacement of bone into a mix of cementum, bone, and fibrous connective tissue. They can be single or multiple and can be associated with the apex of a tooth (peri-apical), focal, or widespread (florid). In these cases, there is ill-defined hyperdense or ground glass extending through the bone of the mandible.

Cementoblastoma

These are cementum forming tumors associated with the tooth root, most commonly the first molar. There is an area of sclerosis at the rooth of a tooth with a rim of surrounding lucency.

Condensing osteitis

This is local reactive sclerosis from chronic inflammation or infection. This is often associated with a tooth that has caries or periodontal inflammation.

Summary

Thank you for checking out this video and short tour of the range of odontogenic lesions you might see. There is a lot of overlap between these lesions, but hopefully you can start to recognize some of the key features.

Be sure to check out the other videos on other head and neck topics or the head and neck YouTube Playlist

See this and other videos on our Youtube channel

Brain imaging course – Unknown case 4

Posted on by Brent Weinberg, MD

Brain imaging course – Unknown case 4

This video is the 4th unknown case that goes with the brain imaging capstone course. If you want to follow along, you can find all the images for the case at the brain capstone page.

Introduction

65 year-old male with possible ground level fall found to be altered. On Coumadin for DVT.

Interactive review

This case features a CT showing a hyperdense hemorrhage in the extra-axial space. You first see it in the left middle cranial fossa and going along the temporal convexity all the way up to over both cerebral hemispheres. There is significant mass effect with uncal unherniation and complete effacement of the basal cisterns. There complete compression of the left lateral ventricle with entrapment of the right lateral ventricle.

Another finding that you can see is hypodensity in the left PCA distribution, which suggests that there is an infarction. This is from mass effect on or stretching of the PCA.

Interactive question 4a

What additional complications do you see on this case? From the explanation, you can see that you have all the complications, including midline shift, uncal herniation, infarct, and ventricular entrapment.

Interactive question 4b

What territory is the infarct in? The left PCA distribution

Diagnosis and Summary

This is a case of acute subdural hematoma. This can occur in patients who are older, who have falls, or who are on anticoagulation. There are a lot of potential complications that you can see in this case, such as ventricular entrapment and hernation.

You can tell the difference in subdural and epidural hematoma most of the time. Subdural hematomas are crescent shaped, cross sutures, and cross along dural reflections. Epidural hematomas are almost always associated with fractures and high energy traumas.

Thanks for tuning in to this case. There are a total of 7 cases you can review on your own at the website and explanations will be posted here.

See all of the brain course videos on the brain course playlist, or go back to the brain capstone course page. Be sure to check back in for additional videos in the future or check out the website at https://www.learnneuroradiology.com

 

Brain imaging course – Unknown case 3

Posted on by Brent Weinberg, MD

Brain imaging course – Unknown case 3

This video is the 3rd unknown case that goes with the brain imaging capstone course. If you want to follow along, you can find all the images for the case at the brain capstone page.

Introduction

62 year-old male with new onset of left sided weakness, left facial droop and right eye pain

Interactive review

In this case, there is a CT showing a large hypderdense hemorrhage in the right parietal lobe. There is a lot of surrounding edema and mass effect, with effacement of the sulci, herniation from right to left, and complete effacement of the right lateral ventricle. The coronal and sagittal view confirm these findings.

This hemorrhage appears to be in the brain parenchyma, and the most common cause of a parenchymal hemorrhage is hypertension. You can also get hemorrhages from other causes such as cerebral amyloid angiopathy.

Case findings summary

A summary of the imaging findings is reviewed here.

Interactive question 3a

Vascular imaging in this patient is negative, what is the next step? The next step in this patient is neurosurgical consultation, as the patient is at high risk of herniation and death from the hemorrhage.

Companion case

This shows a similar case of hypertensive hemorrhage, only in this case there is extension of the hemorrhage into the ventricles, or intraventricular extension.

Interactive question 3b

What is the major potential complication in this companion case? Because of the intraventricular extension, the patient is at high risk of hydrocephalus, either from outflow obstruction or communicating hydrocephalus.

Diagnosis and Summary

This is a case of hypertensive hemorrhage. These mostly occur in older patients, with common locations being the thalamus, basal ganglia, pons, and cerebellum. You can get them in the cerebral hemispheres as in this case, although it is less common and you might think of other causes such as venous infarct or cerebral amyloid angiopathy. These cases are extremely common and one of the most common things we see in neuroradiology.

Thanks for tuning in to this case. There are a total of 7 cases you can review on your own at the website and explanations will be posted here.

See all of the brain course videos on the brain course playlist, or go back to the brain capstone course page. Be sure to check back in for additional videos in the future or check out the website at https://www.learnneuroradiology.com

 

How to read a 4D parathyroid CT

Posted on by Katie Bailey, MD

How to read a 4D parathyroid CT

In this video, Dr. Katie Bailey describes how to review a 4D parathyroid CT for the presence of a parathyroid adenoma. We cover the features of a multiphase, or 4D, CT of the neck and the imaging characteristics which are typical of parathyroid adenomas.

What is 4D parathyroid CT?

It is a multiphase contrast CT, so you have three dimensions in space, and the 4th dimension is time. It is often done to evaluate for the possible presence of abnormal parathyroid glands or a parathyroid adenoma. There are usually 4 parathyroid glands along the posterior margin of the gland.

How to find a parathyroid adenoma

If looking for a parathyroid adenoma, you should be looking for a round or oval nodule along the posterior margins of the thyroid. A good way to differentiate between a lymph node and a parathyroid is that the vessel often goes to the pole of a parathyroid but to a hilum of a lymph node. If you don’t find one in the expected location, you can check more distant places in the deep neck.

Appearance of parathyroid adenoma

On a noncontrast image, the nodule should be lower in density than the normal thyroid, which contains more iodine.

On arterial phase imaging, a parathyroid adenoma enhances more than the adjacent thyroid.

On venous phase imaging, the adenoma enhances less than the adjacent thyroid because the contrast washes out faster.

Practice case 1

In this practice case, you can see a nodule along the left inferior tracheoesophageal groove. It enhances avidly on the arterial image and washes out on the more venous phase. The sestamibi scan confirms the finding.

Practice case 2

This case shows a normal thyroid which is displaced anteriorly on the left. There is a heterogenous nodule along the posterior margin and extending along the esophagus. The greater heterogeneity of this lesion is caused by hemorrhage

Summary

4D CT is a focused tool to look for parathyroid adenomas in the setting of a clinically suspected adenoma, usually characterized by hypercalcemia. You can use it in conjunction with clinical features, nuclear medicine

Be sure to check out the other videos on other head and neck topics or the head and neck YouTube Playlist

See this and other videos on our Youtube channel

Brain Bites – Central Neurocytoma

Posted on by Brent Weinberg, MD

Brain Bites – Central Neurocytoma

Welcome to our new series, Brain Bites, where we are going to be making short videos featuring other physicians and learners explaining neuroradiology concepts in short, easily digestible bites. Hopefully these videos will give you some quick points so that you can become more effective at evaluating brain and spine imaging.

Today’s video is focused on central neurocytoma and is presented by Stefani Yates, a medical student at Morehouse School of Medicine.

Central neurocytoma is a heterogeneous mass which usually occurs in the frontal horn of the lateral ventricle along the septum pellucidum, or the then septation that separates the lateral ventricles. These masses are usually heterogeneous on T2, isointense or similar to gray matter on T1, and enhance heterogeneously and avidly. In this case you can see a mass in the left frontal horn along the septum pellucidum.

Patients can be asymptomatic or they may present with nonspecific features such as a headache, as this patient did. Treatment is usually surgical resection, or they can be conservatively managed.

The differential diagnosis includes:

  • Ependymoma – an enhancing mass more common in the 4th ventricle
  • Subependymoma – a ventricular mass which usually does not enhance
  • Meningioma – a ventricular mass most common in the occipital horn which has more homogeneous enhancement.

So, if you see an intraventricular mass along the septum pellucidum, keep in mind central neurocytoma. Thanks for watching today!

Check out the full Brain Bites page or the Brain Bites YouTube Playlist for more short learning content.

Neck Imaging Reporting and Data System (NI-RADS) Introduction

Posted on by Katie Bailey, MD

Neck Imaging Reporting and Data System (NI-RADS) Introduction

In this video, Dr. Katie Bailey walks us through an overview of the Neck Imaging Reporting and Data System (NI-RADS) system, including why it was created and a basic overview of the principles and categorization. You can learn more about the American College of Radiology (ACR) NI-RADS system from the ACR website. In this talk, we will walk through some NI-RADS categories, show examples of each, and go through a practice case.

Introduction

NI-RADS was designed to standardize surveillance and follow-up recommendations for tumors of the head/neck and aerodigestive track, including the oral cavity, nasal cavidy, nasopharynx, oropharynx, hypopharynx, and larynx. Most of these are squamous cell cancers but some, such as salivary gland, orbital, and sinonasal tumors are also included.

NI-RADS categories

NI-RADS categories include the primary tumor site and neck to look for recurrence. There are categories from 0-4 depending on the level of suspicion. Each category has a recommended management decision associated with it. Some of the categories are split into subcategories.

NI-RADS 1

Category 1 includes includes expected post-surgical changes and nothing concerning or masslike. Sometimes you can have linear enhancement or mucosal edema, but you definitely don’t have nodular or masslike disease. If you have PET, there will be minimal or no uptake. These patients can have expected follow-up.

NI-RADS 2a

In category 2a, there can be come focal mucosal enhancement, but it would be unlikely to be masslike. If there is FDG-PET, it would be mild to moderate uptake only. These patients may need direct inspection by scope.

NI-RADS 2b

Category 2b may have some ill-defined enhancement in the deep soft tissues. This distinction is important because any abnormal soft tissue may not be visible along the mucosa, so scoping will not be useful. These patients likely need a short-term follow-up.

NI-RADS 3

NI-RADS 3 has a new or enlarging primary mass or lymph node. These tend to be nodular or masslike and probably have intense focal uptake on PET. These patients probably need a biopsy.

NI-RADS 4

Category 4 is for pathologically proven or definite radiologic and/or clinical progression. Because this is definitive progression, these patients need new clinical management or treatment. On follow-up imaging, you may find new disease in a new or distant location. This would be described separately.

Practice case

This practice case is a maxillary sinus squamous cell carcinoma. The initial tumor is very extensive. The first posttreatment scan shows postsurgical changes, with a very small area of focal FDG uptake posterior to the flap. The MRI is very reassuring with no masslike or suspicious enhancement. However, because of the deep PET uptake, we’ll call this a 2b so that it gets short term follow-up.

On the short-term follow-up, the area of nodular enhancement seen previously has worsened considerably, and there is a great deal more involvement of the skull base and adjacent structures. The FDG-PET is very highly avid. We will call this a category 4.

Summary

In summary, we show a flow-chart with the NI-RADS categories so you can quickly review. Hopefully this helps your review of post-treatment head and neck cases go more smoothly.

Be sure to check out the other videos on other head and neck topics or the head and neck YouTube Playlist

See this and other videos on our Youtube channel

Brain imaging course – Unknown case 2

Posted on by Brent Weinberg, MD

Brain imaging course – Unknown case 2

This video is the 2nd unknown case that goes with the brain imaging capstone course. If you want to follow along, you can find all the images for the case at the brain capstone page.

Introduction

60 year-old man with personality changes and lack of motivation with flat affect for 1-2 months

Interactive review

In this case, there is an MRI showing a mass in the bilateral frontal lobes, but more in the right frontal lobe. It crosses the corpus callosum. It is markedly enlarged with FLAIR and T2 hyperintensity, abnormal DWI suggesting high cellularity, and a few areas of hemorrhage on SWI.

On post-contrast imaging, you see a mass with peripheral enhancement and central necrosis (a ring enhancing mass). There are multiple additional areas of enhancement (multifocal enhancement). Findings are very concerning for a high grade tumor, such as a glioblastoma.

Case findings summary

Here you can see screenshots of the findings which we saw in the interactive case review.

Interactive question

What makes this tumor appear high grade? Central necrosis, thick nodular rind of enhancement, multifocal enhancement, restricted diffusion, crosses midline (corpus callosum) 

Diagnosis and Summary

This is a case of glioblastoma. These are high grade tumors of the brain which have a very poor prognosis, and are one of the few aggressive lesions which will cross from one side of the brain to the other. This is a classic appearance of GBM.

Thanks for tuning in to this case. There are a total of 7 cases you can review on your own at the website and explanations will be posted here.

See all of the brain course videos on the brain course playlist, or go back to the brain capstone course page.

Brain imaging course – Unknown case 1

Posted on by Brent Weinberg, MD

Brain imaging course – Unknown case 1

This video is the 1st unknown case that goes with the brain imaging capstone course. If you want to follow along, you can find all the images for the case at the brain capstone page.

History

83-year-old female with h/o hypertension presents with altered mental status, slurred speech, left hemiplegia and right sided gaze

Interactive review

In this case, there is a CT showing an area of hypodensity and loss of gray-white differentiation in the right cerebral hemisphere. There is a corresponding area of vascular occlusion at the right carotid terminus on the CT angiogram

On the MRI, you can see a large area of DWI abnormality in the left MCA distribution confirmed on the ADC imaging. There is corresponding FLAIR abnormality. These are all findings of an MCA distribution infarct.

Case findings summary

Here you can see screenshots of the findings which we saw in the interactive case review.

Interactive questions

Test your knowledge learned during the rest of the course and on this case.

Summary

Thanks for tuning in to this case. There are a total of 7 cases you can review on your own at the website and explanations will be posted here.

See all of the brain course videos on the brain course playlist, or go back to the brain capstone course page.