Radiological anatomy of Oral Cavity (Tongue/Buccal Mucosa) - Dr Nivedita Chakraborty

Uh so a very good morning to everyone. I

Dr. Punam Jooshi welcome you all to our head andneck actric academic classes. Uh

so for today uh our topic of presentation is uh radiological anatomy of oral cavity uh tongue and buckar makosa and uh speaker for the same is

Dr. Niveita Chakravarti. Dr. Dr. Nidita is associate professor in department of radio diagnosis at ACTRA tatamal center navi Mumbai. So with this we welcome Dr.

navi Mumbai. So with this we welcome Dr. Nidita. Uh Nidita please go ahead with

Nidita. Uh Nidita please go ahead with your presentation.

>> Thank you ma'am for the kind introduction. I'll just share my screen.

introduction. I'll just share my screen.

Hope my screen is visible. My slide is visible.

>> Yes. Yes. Yes it is.

>> Okay. So I'll be discussing the radological anatomy of uh tongue and buckle mucosa.

Before going into the specifics, let me just give you an overview of the oral cavity margins. So oral cavity begins

cavity margins. So oral cavity begins anteriorly with the lip and superiorly the margin is between the hard pallet and the soft pallet. Posteriorly at the

junction of anterior 2/3 and posterior 1/3 of tongue. So you all know posterior one/ird of tongue is a part of oro fairings and posterolateral boundary of the oral cavity is formed by the palatto

glosses muscle which is which forms the anterior tonsular pillar. So

palattolossis muscle is a part of extrinsic muscle of tongue. Now oral

cavity has got a centrallylo um oral cavity proper which houses the tongue and laterally located vestibule which is a space a cleft which is

bounded laterally by the buckle mucosa.

Now let's go into the uh specific uh specifics of tongue is my pointer visible or I'll use the laser pointer.

>> It is visible nita but pointer would be laser pointer would be better. Yeah.

Yes.

>> Okay. So, um you all know that uh tongue has four pairs of intrinsic and four pairs of extrinsic muscle. So, let's

look at the intrinsic muscles of tongue which has which are completely located within the tongue and have no external attachments longitudinal muscle the hypoense part.

This is the MRI. This is the superior longit.

MRI. This is the superior longit.

This is the inferior longitudinal muscle the hyper and in between these fibers are the vertical muscles and on coronal this is a coronal T1 weighted image you

can see these transversely oriented fibers which are extending from the midline to on on either side this is the transverse muscle. So these are the

transverse muscle. So these are the intrinsic muscles of tongue. Now coming

to the extrinsic muscles of tongue you have the paired geneoslossus muscle which is running anteroposterally. This

is the aial T2- weighted MR. So you have the anterior posterior located on either side of the midline. This is the geneoglossis. This is the hyoglossis

geneoglossis. This is the hyoglossis muscle located lateral to the geneoglossis muscle. Now the gossus

geneoglossis muscle. Now the gossus muscle is a fan shaped structure on the sagittital T2 weighted MRI. This fan

shaped structure is the gossis. On

coronal T1 weighted image this is on either side of the midline. This muscle

these muscles are the geneoglossus muscle. Now next is the palattolossis

muscle. Now next is the palattolossis muscle. As I've already told you this

muscle. As I've already told you this forms the anterior tonsular pillar and its attachment is from the soft pallet and it interdigitates with the hyoglossus muscle.

The stylossus muscle which attaches from the styid process and again interdigitates with the hyoglossus muscle. So these are the four extrinsic

muscle. So these are the four extrinsic muscles of tongue. Now let's talk about the root of tongue. So root of tongue is the comprises of the lingual septum. So

this lingual septum this midline structure it is a fibrous structure which divides the tongue into each half.

So root of tongue comprises of the midline lingual septum. The geneoglossis

muscle on either side and the go hyoid muscle which is not an extrinsic muscle of tongue or an intrinsic muscle of tongue. So the root of tongue comprises

tongue. So the root of tongue comprises of lingual septum the paired golossus muscle and the ginohard muscle. You can

see on the exial view inferiorly this is the gohard muscle on either side. On

coronal view this is the gohard muscle which is located above the myoid sling.

I'll come to the floor of mouth and myoid later. So this is the geninoid

myoid later. So this is the geninoid muscle and on sagittital this inferiorly located antroposteriorly extending muscle is the goid. So this is the root

of tongue and this is the hyoid bone. So

as you know bone has a cortex and a medula. So you can see on T2 the

medula. So you can see on T2 the hypoance part is the cortex and the bright marrow fat is the medula. So this

is on sagittital view. This is a lesion you can ignore reaching up to higher bone on the sagittital weighted MR. So when we look at the distance of the tumor

from the hydro bone, we actually look at the tumor on the aial plane and then on the corresponding sagittital plane we measure the distance the cranioordal

distance of the tumor from the hydone.

Now again I will you ignore the disease part and let's so

formed by a U-shaped myoi sling. So

myoid sling as you know is attached to the inner margin of the mandible and it is supported by the ginohad but geniohide is not a part of floor of

mouth. Now s

mouth. Now s also includes the so sublingual space is located superdial to the myoy sling. Now in eggial view

this is the hyoglossus muscle. This is

the myoid muscle. So myoid muscle is located laterally as it attaches to the mandible and the mediallylo antroposterally oriented muscle is the hyoglossis.

Most fibers of muscle space this is the sublingual space which is located lateral to the geneoglossis

muscle medial to the mandible. So it

divides the sublingual space into medial and lateral compartments. So medial

compartment what it does is comprise of lingual artery vein and glossopharangial nerve and laterally hypoglossal nerve and the lingual nerve.

So this is the floor of mouth the sublingual space as well as the myoid.

Now this is just to give you an example.

These are the neurovvascular bundles located laterally which run into the sublingual space and depending upon the encasement degree of encasement we call

it encased involved or not. Now let's

move on to the vestibule and the buckle mucosa. So as I've already said the

mucosa. So as I've already said the laterally located part of the oral cavity is the vestibule. Vesticle is

basically a space a clif that is bounded laterally by the buckle mucosa on the inner lining of the cheek and the reflection of the mucosal fold onto the

upper part of the maxilla maxillary gingiva forms the upper gingivo buckle culcus and the mucosal fold reflecting onto the mandible forms the inferior

gingivo buckle culcus. So this is upper and the lower gingivo buckle culcus. Now

posteriorly this vestible opens into what is known as the retroolar trione.

Now retroolar trione is basically a mucosal fold. It is a triangular shaped

mucosal fold. It is a triangular shaped mucosal fold which has an aex and a base. So this is obliquely oriented uh

base. So this is obliquely oriented uh sagittital plane in which you can see the entire retroar trione. So apex is located posterior to the upper molar and

base is located posterior to the lower molar.

We'll discuss about the uh attachments of the retroolar trione but before that let's focus onto the buckcometric space.

Now this is the buckle mucosa. Lateral

to this is the buxinator muscle. This

buxinator muscle attaches to the terrigo mandibular raf. I'll come to it later.

mandibular raf. I'll come to it later.

Laterally this bcometric space is formed by the zygomaticus major. This is the zygomaticus major muscle. And

posteriorly this space is bounded by the massitor muscle and it contains the paroted duct.

Now coming to the terrigo mandibular rafé again you can ignore this part which you know this is a tongue lesion.

Let's focus onto the normal side on the right. So this is the retroar trione.

right. So this is the retroar trione.

Now this is the buxinator muscle which attaches to the terigo mandibular rafé.

Now terrigo mandibular rafé is a structure which is located medial to the retroar triion. Now why is this

retroar triion. Now why is this important? So the buxinator muscle is

important? So the buxinator muscle is also attaching to termandular rafé and this terrigo mandular raf provides attachment to the superior farangial constrictor muscle. This hypoens muscle

constrictor muscle. This hypoens muscle which you can see over here it is thinned out. This is the superior

thinned out. This is the superior fangial constrictor muscle and the tero mandibular raface superiorly provides attachment to the medial tergoid plate that is terod hamulus of the medial

terod plate which means that any disease within the superiorly it can get upstaged into the high ITF because this provides is attachment to the tergoid hamulus.

Okay. So now few concepts about the infrateemporal fossa and the masticator space. So infratemporal fossa is

space. So infratemporal fossa is basically the structure between the medial portion of the ramis of mandible

and the fngial mucosal space. So over

here medial to the ramis of mandible and the fangial mucosal space whatever structures are there that comprises of infrmporal fossa which means

parapharangial space is also a part of infrmporal fossa and which also means that massitor which lies lateral to this

ramis is not a part of infrmporal fossa.

So now coming to masticator space as you can see masticator space obviously has the muscles of mastication including the masseta but the parapherential space is

not a part of the mass masticator space.

Now we talk about low and high ITF. So

you know a supra notch disease is at high ITF level and infran disease is at low ITF level. But can we uh understand that on an eggial scan as well? Yes we

can. So you can see this is a single ramis of mandible. Once this divides into two anteriorly located coronoid process, posteriorly located condalar process. So once it divides into two,

process. So once it divides into two, you know you are at the high ITF level.

Till it is a single bone you are at the low ITF level. So medial tergoid is at the low ITF level and lateral tergoid muscle you can see the two bones have

the bones have divided. It is at a high ITF level. Now few words about mandible.

ITF level. Now few words about mandible.

So um mandible you know is a bone so it will have a cortex and a medula. Again

this h high dense part is the cortex and the hypodense part is the marrow containing fat. Okay. So now the alvular

containing fat. Okay. So now the alvular part which is on the inner side adjacent to the tongue is known as the lingual plate and the alvular cortex which is

adjacent to the buckle mucosa that is on the outer side is known as the buckle plate. So it has a lingual plate and the

plate. So it has a lingual plate and the buckle plate and inner is the mand marrow. So here you can see now this is

marrow. So here you can see now this is the mental forammen which continues as the mandibular canal and then posteriorly it opens into the mandibular

forammen. So inferior alvular nerve

forammen. So inferior alvular nerve traverses through enters through the mental forammen and traverses through mandular canal and exits through the mandibular forammen.

Now just few words about the teriggo palatine fossa. So teropalatin fossa you

palatine fossa. So teropalatin fossa you know is located at high ITF level laterally through the tergo maxillary fissure over here it opens into the high ITF medially through spphenopalatine

foramin it opens into the nasal cavity.

Now inferiorly inferome medially it opens into the vidian canal which further opens into the foramin lacerum.

An antos superiorly via infraorbital forammen it opens into the orbit and posteros superiorly this at a higher level it opens into the middle cranial

fossa through the foramin rotundum. So

forammen on coronal view this is a coronal CT. The laterally located

coronal CT. The laterally located foramin is a foramin rotundum. Medially

one located one is the vidian canal. So

these are all the connections of the terrigo palatine fossa.

Now this is the this is another foramin.

What is this? This is foramin oale.

On coronal view this is how the foramin ovale appears. It opens into this

ovale appears. It opens into this cavanous sinus and it has connections to melcape. And on coronal T1 weighted

melcape. And on coronal T1 weighted image this is the foramin ovale.

I think this brings me to the end of the talk. Any questions?

talk. Any questions?

>> Yeah, thank you Nita. Uh I think it's a short and crisp lecture. I think it's mainly about the radological anatomy only uh oral cavity. So if there are any questions uh we can take them. Please

put them on the chat box immediately.

So Nita uh like for tongue lesions what I was going to ask you is like like which is the best section I do though I understand because from the radological

radiologist perspective you do see all the uh planes in all the planes but for as a surgeon which like we discuss always I somehow find it easier to see

tongue in the uh this plane uh the sagittital plane because that gives me the anatomical understanding which is more in sync with the surgical planning.

So uh like your take on like uh what in what section do we see all the muscles like if I want to see all the four extrinsic muscle what section would be good?

>> I would see uh always the actual plane.

So we always look at the actual plane first. But having said that as I said we

first. But having said that as I said we if you have to measure something uh it is just not one plane that we rely on.

So if it's a crano cordal extent if I have to measure for example distance from higher bone which forms an important part of planning then I would look at the sagittital plane and also correlate it with the eggial plane. I

would uh look at the tumor on the eggial and correlate it on the corresponding uh sagittital plane and measure the distance. So all the planes are

distance. So all the planes are important but if you ask me one plane where we most of the times measure also even depth of invasion all it is the sagital plane. It's a plane.

sagital plane. It's a plane.

>> Yeah. No, but I agree with you that we have to see it in all the planes because even for surgically also it has to be seen threedimensionally that we have to see in every dimension that how the

disease progresses. Uh [snorts] if there

disease progresses. Uh [snorts] if there are any questions we can take them in the chat box.

Yeah, I think there was nothing much to discuss in the radological anatomy. So

>> yes, yes, I do understand that. But I

wanted it especially for radological anatomy only because that's the topic which as a at least surgeon or clinician we don't know much. I think one is indication of MRI in oral cavity

cancers. So when will you do MRI? Huh?

cancers. So when will you do MRI? Huh?

>> So for tongue lesions, MRI because MRI gives the best soft tissue uh uh signal intensity. Therefore for tongue lesions

intensity. Therefore for tongue lesions we do MRI for others we can do CT.

So sometimes sometime back we had some discussion in our department. Do you

think like a contrast enhance? Okay. So

I think there is another question let us first take that. So for IT or for retroo what would you prefer MRI or CT?

>> We can uh see all the structures on CT itself. We don't specifically need an

itself. We don't specifically need an MRI for retrooarone or a high ITF or an ITF when we need is when you know we have to look at some intraranial

extension of the perinural spread only then an MRI will be required otherwise CT is CT will be sufficient.

So what you're saying is that for ITF or for trione we have to do normally CT contrast enhance CT is good enough unless there is some doubt about the

parinural invasion. where we MRI can

parinural invasion. where we MRI can have an incremental value right yes >> and even most of the perural spread also can be visualized on CT so if the

cranial extent of the perinal spread as and when it reaches the skull base and beyond that's where the role of MRI is more important that's where the incremental role of MRI comes otherwise

in routine practice even perinural spread can be visualized directly as well as via indirect signs on CT scan itself so What are the different these

indirect signs nita on CT scan? Suppose

we have CT only. So how do we see that perural invasion?

>> Yes. So we'll compare like in CT we have you know u the advantage of comparing it with the contrateral side. So if there is an aymmetrically enlarged mandibular

forammen I'm talking about you know inferral nerve within the mandibular forammen or uh the mandibular canal asymmetrically enlarged the fat is

ephaced and the then surrounding the nerve then these are the indirect signs of you know perinural spread even directly we can see so if I have one

I'll just show you uh over here suppose usually this is a mandibular foramin I don't know if you can see my screen. So

this is the mandibular front.

>> We can see we can see.

>> So if this is asymmetrically enlarged.

So then secondly there is always a fat uh surrounding the nerve as it exits the mandibular forammen. So if that fat is

mandibular forammen. So if that fat is effaced if only we can see the nerve then these are the signs of uh perinural spread.

>> Right. Uh there is another question nita that uh does the skill involvement need MRI? Do you think like any imaging is

MRI? Do you think like any imaging is useful uh for assessing the uh this uh skin involvement? Like I think you're

skin involvement? Like I think you're doing one study also on CT scan. So is

CT useful, MRI useful if you have to look for skin involvement especially for buckle mucoslegions.

>> Yes. So uh uh so skin involvement firstly only if there is a subcutaneous edema or it is only extending up to subcutinous plane then we should not overall it because CT has a tendency to

overall skin involvement. So unless

there is a frank ulceration um uh then uh unless there is a frank ulceration we should not just label it as the skin is involved. So it has to be breached. We can very well see the skin

breached. We can very well see the skin involvement on CT scan. But the doubt arises when there is only you know edema is there subcutaneous you know fat stranding that should not be labeled as

a skin involvement it should be reaching up to the surface and breaching other >> yeah sure continue please so even on pathology report they uh give the skin

involvement as epidermis and dervvis involvement separate so epidermis is when the uh the skin u that is breached externally we can see ulceration the

continuity of the skin is lost that we can see but CT generally has a tendency of upstaging it. If the tumor reaches up to the uh skin but it is not ulcerating

then I would not want to over call it as a skin involvement.

>> So I think why this question usually the surgeons would ask nita is because many times we have to remove the skin you know that just to know if we can do it

pre-operative.

>> So do you think MRI would be in involvement if you want to do I mean um this will also give the same uh impression I mean it it will not have

some incremental value for skin involvement because that's what we are going to see even on CT scan I think what will be important is an ultrasound if you because you want to know the

depth from the skin uh how deep the tumor is located isn't it >> exactly how deep the tumor is located from the skin. So that an ultrasound would be

right CT has told us is that and CT is good enough. We don't have to do any uh like

enough. We don't have to do any uh like MRI or any other investigation added investigation and most of the time it is not going to help us with the assessment for the skin. Most of the time it is

going to be a clinical assessment and we do overt treat the skin involvement many a times and I think that is quite okay when you are treating a quite aggressive

mucosa regions. So nita another question

mucosa regions. So nita another question is how to measure the volume of tumor and it what is its importance? Volume of

tumor so we take a measure we generally don't measure volume of tumor for oral cancer. We just measure the size and the

cancer. We just measure the size and the depth of invasion.

So uh size is of course the AP transverse and the craniocordal dimension in all the three planes like uh AP will be in the exial plane and and the transverse also dimension and

cranioordal plane either we can take a sittietal or a coronal plane for measuring the cranodal. So these are the three dimensions that we give and depth of invasion whichever in whichever plane

we find the maximum depth either in aial or in coronal from the margin to how deep it is excluding the proliferative part and

including the ulcerative part if any >> correct so how does it like do you think it has some importance I think langial agent there is something

>> for oral cavity Foral cavities it has not been proven even for oroparangial cancers it has been proven to be of value uh the tumor volume but not for

oral cavity. So there is data to suggest

oral cavity. So there is data to suggest that if the tumor volume not for oral cavity but for lingel regions and oroaring regions like nidita said that many a times the volume of your disease

will correlate with your response to radiotherapy. So if it's naturally if

radiotherapy. So if it's naturally if it's a low volume disease the response rates are going to be better. If it's a quite a large volume disease then many of times it is better to uh provide some

other treatment. Not that it is done

other treatment. Not that it is done regularly but there can be impaired response or decreased response because the tumor volume is large. So something

like that it works on that principle. So

another question postaduent disease status say there was buckle mucosa leion with skin infiltration what would you do? Similar question MRI versus CT to

do? Similar question MRI versus CT to judge the extent of the disease.

>> No CT whatever we have imaged the tumor with the primary modality we have to use the same modality for the post uh NCAT assessment. So it should be CT. If you

assessment. So it should be CT. If you

have done CT then we have to compare it with the CT right. Compartmental

resection and role of MRI. Uh so I think it is more for me than so I think again these we are talking about two different things. uh like if you want to know when

things. uh like if you want to know when should we do compartmental resection it's a different topic so compartmental resection that suppose we are doing for tongue so we are going to remove like at

least the half of the tongue and we are going to go till the hyoid and we are going to go laterally till the mandible and medally till the midline refer that is a compartmental resection so if you

are doing a tongue resection then like nidita said we have to do MRI but if same compartment if the compartment resection is for a buckle mucosa or RMT

lesion which is like where you are going to do a ITF clearance where the superior margin is going to be the base of the skull lateral is going to be the mandible medial is going to be the

teroid plates then in that case you will be doing a CCT scan so it doesn't matter that what mental resection or you are just doing a

wide excision it only depends upon the so you don't have to do MRI and there there's no direct correlation between the compartmental resection and MRI. So

as per the need you have to do the imaging. I hope that answers the

imaging. I hope that answers the question.

So uh does edema represent lymphatic blockage or disease in MRI?

So it could represent either just by seeing edema we cannot come to know and so enlarged lymph nodes we can always see

that on imaging.

So even uh in patients who have not had enlarged nose they can present with edema. So um that just on imaging we

edema. So um that just on imaging we cannot say whether it is due to uh sudden tumor or it is due to lymphatic blockage.

So I think the question I think is more for the I think bakala what I feel is because uh again so the question is more

like that if we do uh on MRI we are seeing some sort of this so on MRI if we see

there is edma we did does it represent uh the disease or does it represent lymphatic blockage I think they want to know that how should we take it. That is the

question.

>> Yeah. So the thing is uh in buckle mucosa we always see there is a surrounding fat stranding. We always say if we always see if there's a surrounding fat landing extending up to zygoma which will you know change your

management to whether to give n or up front operate. So uh we don't know

front operate. So uh we don't know whether that is a tumor involvement but in most of the cases that turns out to be that it is due to tumor involvement and not just uh you know it could be

lymphatic blockage it could be tumor but it is some sort of a disease whether in the lymphatics or in the uh uh tumor or direct tumor infiltration. So it should

be considered as a uh I'm talking about only the buckle mucosa part. Now in the tongue so there have been studies you know I don't have that case because it's just of an anatomy many a times

surrounding the tongue lesion on postcontrast images we see uh edema postcontrast as well as on stir we see

edema so and those tumors I in my study I've recently concluded the tumors which have edema periteral edema they perform poorly as far as survival outcome is

concerned so they have inferior overall all survival. So in that case tumor I

all survival. So in that case tumor I think peritummeral edema should be considered as a disbart of a disease.

>> Yes I completely agree with you nita that see whenever you have edema and it is corresponding with the sight of the disease it doesn't matter if it is

lymphatic blockage or it is disease because ultimately this lymphatic blockage is because of the disease itself. So you have to take it as

itself. So you have to take it as disease and when you take your margins also you have to take beyond the edema.

Okay. So many times it may be a bit difficult on clinical examination. You

may see a bit more on the radiology but I completely agree with Nivea that edema is synonymous with disease if it is corresponding with the disease. So I

think that I hope that answers the question. I think Nidita this one

question. I think Nidita this one question I'm sorry for infatoral fossa involvement. So I

would request you again to uh if you could tell us that when do we do CT and when do we do MRI if you can tell sitewise also I know in some cases we'll

need MRI for certain reasons or CT for certain reasons but if you could tell us at least for the oral cavity site wise where would you say we have to do CT and where we have to do MRI? I saw a lot of

confusion regarding this.

>> Okay. So uh in general uh if there is a tongue involvement if there's a lesion in the tongue we have to do MRI there is no role for of CT in that but other than

that like if it's gingivo buckle carcinoma hard pallet RMT ITF involvement all these CT is the uh

modality of choice and uh of course I'm not going into the details of oroarings but for oroarings again it is MRI so anything where the lesion is in the soft

tissue that requires MRI for evaluation and anything which is you know surrounded by bone um and so that requires CT for evaluation. So I

>> so Nidita for hard pallet you will do CT and for soft pallet you >> Yes. Yes. So it is more of likely

>> Yes. Yes. So it is more of likely gives a better clarity.

Other than tongue like nidita said because we are talking only about oral cavity right now please go ahead and do a contra cct scan don't worry about

other things as unneeded we'll do MRI as needed we'll do pet CT okay but the first line of investigation is going to be a contrast enhanced CT for all the

oral cavity lesions uh except correct nita >> yes absolutely >> yes I think there is one more question post new residual disease versus fibrosis due to

response. Can CT differentiate it or we

response. Can CT differentiate it or we need uh uh this diffusion weighted uh uh images to make a call? Okay, so post NAC

um MRI would definitely be better but if you're talking about buckle mucus again I'll have to divide it sitewise you can we cannot have a generalization. MRI

would definitely give a better answer to response compared to CT in general. But

now if we talk about buckle mucosa we can always say uh differentiate a fibrosis from a lesion based on heterogenity of enhancement. If you are

looking at CT scan then hetrogenity will give you uh you know will be more if it's homogeneously enhancing then it will be more in favor of fibrosis. So

that's on CT scan and on MRI definitely a diffusion weighted image would be so restricting diffusion weighted and otherwise

fibrosis will not and there are other signs also T2 hypo inensity of fibrosis whereas T2 intermediate signal intensity of the disease. So this is how uh we

differentiate but it is it has to be sight wise correct.

Uh so another question as ITF has more of a soft tissue component do we need to do MRI or to see the extent in addition to CT? I think Nita there's lot of

to CT? I think Nita there's lot of confusion regarding soft tissue. I think

this understanding of soft tissue is also a bit challenging. I think I see here. So the thing is see on on routine

here. So the thing is see on on routine CT scans we can provide most of the answers and only in in few of the cases as I said as the disease approaches the

skull base and we have doubt regarding you know forinal extensions uh beyond the teropalatine fossa and all that above cranially there we would you know

look at MRI but if you're looking at a muscle involvement uh so many times if a tumor only abuts then I do not call it involvement and CT has a tendency to

upstage it. So for only abutment is

upstage it. So for only abutment is definitely not a sign of involvement.

MRI will definitely provide a better answer uh with regards to masticator space uh involvement the muscle involvement but you know in routine

practice we are able to differentiate we in all the cases do not require an MRI to uh you know understand whether there is infiltration or not. In most of the

cases CT will be able to provide the answer. If at all there is doubt in few

answer. If at all there is doubt in few of the cases then we may go ahead with MRI but routinely we do not require MRI that's what my takea can we take it as

suppose this is a buckle mucosa lesion or RMT legion which is going to infrateemporal fossa right and but if this is a isolated

infrateemporal fossa lesion yes >> and the hisytologology seems something different basically the origin is from the muscles itself then the probably MRI would be better or you correct me if I'm

wrong.

>> Yes. Yes. Absolutely. Absolutely.

>> So, so please see again I would retiterate the same fact to all of you uh that if it is a oral cavity lesion a contrast enhanced CT scan is good

enough. Radiologist is very confident in

enough. Radiologist is very confident in telling you the extent of the lesion with a good quality contrast and hence CT scan for all the oral cavity lesions

except the tongue. For tongue lesions please do MRI and for rest of the lesion if it is arising from the oral cavity and then it may be going traversing to

other sides subsides that's a different thing and sometimes we may need MRI which will give additional information but that usually is uh will be told to

you by the radiologists themselves. So

that is my uh call on that.

So I think nidita there were a lot of questions I think it was actually very interesting uh this discussion I feel I think there's one more question we'll

take it uh so I think this would be more for me and but we can discuss so do we do biopsy first or imaging first so biopsy prior to imaging I hope that is

the question >> yes so ideally we should be doing imaging first and then biopsy >> I agree with nita so one thing is that the imaging will give you the real

picture because you are only seeing the surface whatever your clinical examination is but you will understand the exact extent of the disease when you have already done an imaging and second

I don't know if how useful it will be to nata but still I feel after you do a biopsy then come a bit

post biopsy some sort of edema inflammation so I would suggest It is always better to do one imaging followed by biopsy that would

absolutely so if there are not uh any more questions uh we can uh wrap up today's

session and I think uh and there is one more question we'll take it.

>> Yes ma'am. Uh so for recurrent disease what is the investigation of choice in addition to the PET CT?

>> So again it is sight specific. So if

adjuvent so um if adjuant RT has been given PET CT is the modality of choice after treatment completion if then it is a PET CT and depending upon the site for

example if it's nasoperings again MRI if it's tongue again you have to if an additional imaging is required it will be MRI and any other site it's going to be CT scan. So um u and the CT component

you always get to know from the PET CT part. Although the CT component in PET

part. Although the CT component in PET CT is inferior but still the CT component you still have. Um so there will be situation where you might need to do an additional MRI for example

nasoparangial or tongue involvement or oropharangial involvement if there is some recurrent disease. So that is what my answer is for orang you will consider MRita.

Yes. MRI.

>> MRI. Uh and any radio biomarkers which help in assessment of the margins

uh radio biomarkers I mean uh margins.

So on MRI if you are doing our functional so we provide functional information using diffusion uh weighted MRI. So there are no as such

markers but these are the sequences that we use. um like FDG has a um um FDG

we use. um like FDG has a um um FDG component that's provides information on the metabolism. Similarly on MRI we get

the metabolism. Similarly on MRI we get the functional information using the DWI and ADC. So uh these could be the

and ADC. So uh these could be the functional biomarkers you can say. Yes.

But it is I don't think we are going to uh plan our uh this resection especially even post n just based on these markers radio biioarkers

ultimately it is going to be your clinical assessment and radiological assessment. So you have to

radiological assessment. So you have to guidelines right now that what should be so that's a bit of gray area but it is interesting also to know. Uh one more

question, how will you assess the marrow involvement?

>> Okay, MRI is uh uh very good for assessing marrow and CT is excellent for evaluating cortical bone in general I'm

talking about. So um but MRI is you know

talking about. So um but MRI is you know super sensitive but it is not specific.

So you will see sign on MRI when you do MRI tongue you'll see a lot of times you know cortex is intact but there are a lot of marrow signal changes.

$1 and all. So, M

not specific it can be due to ED uh things also unrelated things also but and CT provides uh absolute uh information regarding the cortex. So

unless a cortical uh this bone is breached those MRI signal intensities of the marrow should not be considered as significant. So for MRI it is for marrow

significant. So for MRI it is for marrow it is MRI for cortical bone it is CT. If

you're just comparing the two so who would you advise for MRI? So when will

you advise for MRI?

No. So again it is like if we are talking about B times we can most of the times in fact we can comment on CT scan itself. We are not doing an MRI

itself. We are not doing an MRI specifically to assess marrow. When I

say CT is good for cortical bone doesn't mean that it cannot give information on marrow.

>> Exactly.

>> CT is the if I have to choose between the two I will always choose CT. So CT

scan is going to provide information on the cortic about the cortex there is a breach and we will also get information about the marrow. I'm just comparing the two and and you know telling that which

is better at uh evaluating not absolute that this is only for cortex only for marrow it's not like that so see fair enough for you know cortex as well as

so again for bone involvement oral cavity involvement a contrast enhance CT scan is good enough as in needed after discussion with the

radiologist we can ask for MRI and for the tongue lesions please go ahead and do modality.

So I think uh nita now there has been lot of questions and it was really interesting and I really thank you patiently answering each and every question and with this we conclude

today's lecture. Uh thank you so much

today's lecture. Uh thank you so much Nita ma'am. Thanks ma'am.

Nita ma'am. Thanks ma'am.