Temporomandibular Disk Displacement US and MRI - HD

Introduction

Hi, my name is Diana Ganey.

I am from RBA Medical Center.

I'm the faculty of Medicine of Technion Atfa Israel.

My lecture is about temporal mandibular joint.

This displacement ultrasound and MRI.

Anatomy of the Temporomandibular Joint

The temporal mandibular joint is a synovial joint between the condyle of the mandible and the glenoid fossa of the squamous temporal bone, thele of the mandible and the glenoid fossa of the temporal bone.

It is divided into a lower and upper compartment by a fibro cartilaginous disc that allows movements in both compartments.

TMJ Disorders

The temporal mandibular joint disorders include pain articular noises, restricted jaw function.

They're classified as one subtype of secondary headache disorders by the International Classification of headache disorders, 2004.

40 to 75% prevalence at at least one sign of tempera Mandibular joint disorders appear among adults in USA.

It is more frequent in women and the frequency is increasing due to the influence of psychological tension in today's society.

The disorders may be due to muscle disorders and intraarticular disorders.

This displacement is the most frequent cause of tempera mandibular joint disorders.

Diagnostic Methods

What are the agnostic methods that we may apply?

Conventional panoramic radiography shows only destructive gen changes at a late stage.

CT is not able to visualize particular cartilage.

MRI is the standard for imaging diagnosis of TMJ disorders, but it's relatively low valuable and the cost is high.

So ultrasound is a potential imaging agnostic method that allows dynamic evaluation of the TMJO structures with the advantage of being inexpensive, quick and widely available.

Ultrasound Examination Technique

The ultrasound examination is performed while the patient is sitting in front of the operator.

We employ a high frequency five to 17 megahertz linear rate transducer, and the cuts that will perform will be performer are axial and coronal.

For the axial, we place the probe, we place the probe parallel to the sematic bone and for the coronal, the probe is parallel to the mandibular ramus.

We may perform static scans at mouth closed and maximal opening.

Here the intraarticular disc is seen in between the mandibular condyle and the temporal glenoid fossa on closed mouth and an open mouth and dynamic scans to directly observe the joint disc moving during mouth opening and closing.

Normal Ultrasound Findings

And these are the normal ultrasound findings.

We may see the condyle and the glenoid fossa like hyper echogenic lines and the disc in between like an he hypo echogenic structure with a very thin hyper echogenic line.

In the middle, the normal disc is placed over the condyle head at mouth closed and at maximal opening.

So here we have the scans done with mouse mouth CLO closed, so the disc over the condole of the mandible and keeps the same relationship with the open mouth.

Abnormal Ultrasound Findings

With the abnormal ultrasound findings, anterior this displacement without reduction, the disc is displaced anteriorly at closed mouth and returns to his normal position on opening anterior disc displacement without reduction.

That this, he displaced anteriorly that closed mouth, but does not return to his normal position on opening.

We may also see the degenerative joint disease like conal, erosions and irregular disc morphology.

And these are examples of a pathological position of the disc.

The disc is here displaced, displaced anteriorly, with the mouth closed and at maximal opening, it comes back and places Above the condyle of the mandible.

So this is an example of art anterior disc displacement with reduction.

In this example, the disc is displaced anteriorly on closet mouth, but on open mouth. It remains anteriorly and does not change to the normal position.

MRI Technique and Findings

MRI Technique

The MRI technique, we performed MI with a three three Tesla MRI equipped with high resolution surface coil T two and TT 1 92 weighted sequences in sagittal and coronal planes were performed and the slices were two millimeter width with the mouth closed and the at maximal opening.

Normal MRI Findings

How is the normal disc seen in MR?

I like a biconcave hypo in, hypo intense structure.

The position of the disc when it is normal is over the condyle head at mouth closed and at maximal opening.

So here we have an example of a normal DMJ here we see the normal disc above the condyle of the mandible while the posterior edge of the disc is at the 12 o'clock position.

And on open mouth, see the normal biconcave disc is placed over the condyle of the mandible.

Abnormal MRI Findings

The abnormalities that we may see are the same that we, talked about. On the ultrasound examination, the displacement of the disc anteriorly without reduction.

The displacement anteriorly on a closed mouth but without reduction to the normal position during mouth opening.

And the degenerative joint diseases.

Here we have an example of a anterior displacement of the disc with mouth closed on opening. The disc is placed over the condyle of the mandible, so it is a displacement with reduction, but in this case, the disc is displaced anteriorly and does not remain on the normal position on open mouth.

So it's this displacement without reduction.

Study on Dynamic High-Resolution Sonography

In this study that we performed and was published in 2015 in journal Ofso Medicine, we evaluated the yield of dynamic high resolution sonography for the diagnosis of temporal mandibular joint.

This displacement with the mouth closed and during maximal mandibular range of motion.

Comparing to magne magnetic resonance imaging, we performed 78 TMJ examination in 39 consecutive patients.

The majority were females.

The age was rather low.

They were young from 18 to 77, but the mean was 37 and they were sent from the oral maxillary clinics with TMJ disorders.

The exam, the research was approved by the board, local board and the patient signed an informant consent.

We performed dynamic high resolution sonography with closed and open mouth and MRI also with closed and open mouth performed up to seven days after the sonograph.

We looked for signs of this, this displacement and find this compatible with the degenerative joint disease.

And both examination were performed and interpreted independently by blindly blinded operators.

MRI depict depicted about 30% of normal joints.

This confirm the need of objective examination to make this diagnosis because in a third of the cases, really the joints were normal until this displacement with reduction in 27% of cases and without reduction in 19 percent.

We also saw degenerative diseases on sonography.

The number of normal examination were higher and more or less the same anterior dis displacement without reduction and with the, with the, with reduction and without reduction.

So these were the results.

The overall sensitivity, specificity, and accuracy of sonography for the diagnosis of this displacement were 74%, 84% and 77% respectively for this displacement without reduction with sorry for this displacement with reduction, it was a, we had a better sensitivity and this displacement without reduction, we had a better specificity.

If we compare to the literature, we see that the overall accuracy of ultrasound to detect this displacement ranged from 62 to a hundred percent, the overall sensitivity from 31 to a hundred percent, specificity from 30 to a hundred percent and so on positive and negative predictive value.

So there were very variably results in the literature and it is due to different equipment and operators skill and experience.

The other disadvantage of ultrasound is that we may have a sub optimal depiction of conal disc and glenoid fossa in open mouth when the disc is closed to large bone structures.

Of course, we have all the advantage of ultrasound that we already know, and especially in this case, that is the dynamic technique and the resolution for soft joint tissues that is very high.

Conclusion

In conclusion, dynamic resolution sonography is a potential imaging methods for diagnosis, TMJV displacement and TMJV narrative disease.

Further studies are needed to make dynamic high resolution sonography.

The first line test for the diagnosis of TMJV placement.

Thank you for your attention.