Brain Scans - Lord of the ring enhancing lesions 101

I am Jim Smirniotopoulos, and today we're talking about ring enhancing lesions and this is the 101 class. We have no significant conflicts of interest nor financial disclosures. There are many different patterns of contrast enhancement morphology. we can have homogeneous enhancement, heterogeneous enhancement, and superficial or serpentine enhancement (on the surface). We can also have ring enhancing lesions. Tthey may be uni-locular or complex and multilocular. They can be smooth in them fic an irregular there may be an incomplete ring of enhancement; or, remove enhancement and we can also have a cyst with a mural nodule. Ring-enhancing lesions are a very common differential diagnosis in neuroimaging. Here we see four different patterns of ring lesions. Many people use the mnemonic: "magic doctor" or "magical doctor" to remind themselves about the many different kinds ring-enhancing lesions. Metastatic disease and Multiple sclerosis, an Abscess, Glioblastoma multiforme, sub-acute Infarcts, Cerebritis and Contusion, the V is for Vascular malformations, Lymphoma, demyelination - including tumefactive demyelination lesions (TDL), and radiation necrosis or resolving hematoma. So, how do we sort out these many different kinds of lesions? A ring enhancing lesion has peripheral or marginal enhancement that surrounds a usually central non- enhancing region. There is often times surrounding vasogenic edema. We can evaluate the margin of enhancement to see if it is thick or thin, and a smooth versus a shaggy inner margin. We can look at the extent of surrounding signal change often called vasogenic edema, and we can evaluate the Center for possible restricted diffusion - which is common in abscess. If we go back to the same four different types of ring-enhanceing lesions - we can see one of them is round and smooth suggesting an abscess; one of them is very irregular and has a shaggy inner margin, suggesting in a necrotic neoplasm; one of them shows in incomplete or "open-ring" of enhancement. This is often times seen in fluid secreting tumors which can also produce the cyst in Euro large or morphology when they occur in the posterior fossa cerebellum. We may see surrounding vasogenic edema could email when we have abscesses and neoplasms are both types the fluid secreting as well as democratic but when we have to move fact if the myelination what are the critical features is to identify and incomplete RAM have enhancement and that would be suggestive oven at dancing zone inflammation so these four different types of lesions can be sorted out by looking at the characteristics of the center and the pair delivering or I'm enhancement so abscesses are usually round and smooth with the thin rim you kneel ocular surrounding days agenda good team it's typically very extensive the rim may be high pollen 1022 and they will be restricted diffusion on a diffusion weighted image or eighty map abscesses characteristically have a smooth inner margin because pathologically we're looking at the rim a granulation tissue surrounding the past and the coagulation necrosis the hypo intensity of the rim is oftentimes described as being due to macrophages that have free radicals or atomic oxygen and of course we look for the characteristic pattern a DW eyebright hyper intensity due to the presence have restricted diffusion in the past so abscesses classically have restricted diffusion in a hypo intense rim and they typically comdex all the way around if we look at this pathologic example we can see it has a very very smooth margin we can see the white cell mass and coagulation necrosis in this manner when we have a neoplasm in a chronic neoplasm which is typically very high grade will have a fic an irregular wall a very shaggy inner margin and if you do delayed scanning you can oftentimes see heterogeneous fill-in within the centre democratic RAM so these are the characteristics we look for in a crowded neoplasm irregular fic and variable wall shaggy inner margin complex shape visa Jenica de amor and the rim may or may not be hyperlinked n72 and they're typically is increased diffusion because I've sell lexus and necrosis here's a classic glioblastoma multiforme in the falamos with a very thick and *** margin have enhanced mint and it has central necrosis necrosis is bad in a neoplasm whereas fluid secreting tumors fluid is good if we look at a different case we can see in this diffusion-weighted image other glioblastoma a partially thin RAM and yet a lateral think gramm but we have in increase in diffusion and not restricted diffusion and that's very suggestive that we have micro sis and not plus in an abscess to the diffusion here is not restricted necrosis is had if we compare an abscess have toxoplasmosis with a similar lesion that is in a chronic neoplasm a GBM we can see how different the rims are one is thin and smooth and one is thick and irregular if we compare the diffusion-weighted imaging side by side we can see in the GBM we have a multi lock your appearance a complex parent every min Hansmann and we have increased diffusion from the crosses if we look at at the abscess we have restricted diffusion from parts and the primary cause of the restricted diffusion is viable cells which are typically macrophages in an abscess now when addition to in a chronically applies them cystic neoplasms me also produce a ring enhancing appearance or some pattern a peripheral rim enhancement we could have a mural Nigel part of the wall may not enhance a missus the characteristic suggesting a fluid secreting process rather than democratic process we may have a smooth inner margin the fluid rarely enhances we may see a fluid fluid level here's a classic example of a pilot City castro Saitama on Mr with gadolinium in CT with iodine we can see a mural Nigel and two 9 enhancing fluid lock yours that are not rimmed in or surrounded by contrast enhancement so if we look carefully we do not see any enhancement forming the rim around the fluid-filled spaces this is fluid and not necrosis fluid is good here's another example of a pilot City castro Saitama we can see the Nigel there's a small fluid collection within the Nigel shown by the white Aero but the most important characteristic feature is that we have a rearm surrounding the fluid that is not show any contrast enhancement this is fluid secretion and not necrosis fluid is good the last thing we want to discuss are tumor fact if the myelinated lesions which characteristically have the open ringside or partial remove contrast enhancement and classically they are not surrounded by Visa Jenica team the signal abnormality on flair a proton density weighted imaging ends at the edge of the contrast enhancement so the the are the characteristics we look for into my effective beam island nation the opener incomplete ringside was described in 1996 and in 2000 and is very suggestive for the mileage disease but may also be present in some fluid secreting or cystic neoplasms so when we have to my fact if the myelination we expect there to be relatively little Mass Effect for the size of the lesion we may have an incomplete or open remove enhancement and the period lesional white matter signal abnormality usually is limited or not present at all spreading Vaser Jenica team is uncommon in tumor fact to be my limiting lesions people have also suggested that you may see vessels passing through the lesion on susceptibility weighted imaging which would not occur any other entities that we have discussed this last case the tumor effective the myelination shows that the edge above the signal abnormality ends at the aged the enhancement and the enhancement pattern is forming in incomplete or open ringside and again these are very suggestive up to my fact that the myelination so if we look very very carefully and we see the incomplete ring sign in a specially if we see satellite white matter lesions were thinking about but the mylan eating process so when we examine a ring enhancing lesions we look for these characteristic patterns round and smooth for an abscess shaky inner margin thick wall for an acrostic neoplasm incomplete or nine in hand saying room for a fluid secreting tumor and a partial roof enhancement can occur also into effect could be my eliminating lesions so abscess neoplasm with necrosis fluid secreting tumor and tumor fact if the myelination other causes love the myelination can all have a characteristic pattern I've enhancement this is Jim Sweeney a topless and I want to thank you for your kind attention and I approve this message