Radiology Sheet #3 By Moh'd Bustani

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Radiology Sheet #3 By Moh'd Bustani

Post by Sura on 31/10/2012, 1:55 am


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Re: Radiology Sheet #3 By Moh'd Bustani

Post by Shadi Jarrar on 9/11/2012, 4:53 pm

Lecture # 3 ((11.10.2012))
بسم الله الرحمن الرحيم
Developmental and congenital anomalies
Today we are going to discuss some clinical radiographic cases that you can find in the PDF file already uploaded by the doctor. So we will see a picture, we should identify what type of radiographs this is and describe what we think is abnormal.

I will write what the students were saying if the Dr. agreed with them and will try to answer the questions found in the PDF file at the end of the discussion of each case. (Note: please go back to the softcopy of the PDF file to see the x-rays more clearly, I've added small thumbnails just to link stuff while reading and make things easier).

Case #1:

This is a panoramic radiograph.
* Note: we can't diagnose caries on a panoramic image, we need bitewings to do that but we might say we suspect caries but this is not a diagnosis.

First of all, there is some missing teeth (the whole 4 first molars). If we look at the structure and morphology of the teeth, we will see that the pulp is obliterated and there is no clear demarcation between dentin and enamel ((CEJ)) there is increase in dentin but still you can see enamel all around. The crowns are bulbous and constricted cervically.
So the Differential Diagnosis is Dentinogenesis Imperfecta ((DI)).
- This radiograph is very typical of DI (it can't be anything but DI).
[If you were thinking about Amelogenesis Imperfecta ((AI)), you don’t see the typical diastemas in the AI and there is no obliterated pulp nor bulbous crowns in AI].

Q: What more features you are interested in about the appearance of the patient clinically??
Blue sclera and bowing of the weight-bearing long bones (arch shaped deformity), if these are present then it is associated with Osteogenesis Imperfecta ((OI)), so it will be DI type 1.

Q: if you took a close look you will see as if there is no canine and 3 premolars, what is that??
This is canine but because of attrition and so it looks very "premolarish" but these are canine -lacking it typical morphology- and 2 premolars.

Q: why is this image so noisy?
This was a digital panoramic x-ray (Gendex system), and in digital systems when there is overexposure or underexposure it will be dealt with and fix things for you, so this noise is because of the underexposure in this x-ray. If we recall from last year, the primary radiation and scattered radiation, the primary will produce the signal (what we need) and the scattered will produce the noise. So the digital panoramic system are based on the balance between signal and noise, the noise could be because of underexposure or because the patient's head is very big or the bone density is very high (as in some races), all of that will result in less signal and more noise so the picture will appear unclear.

Note: A story about one of students who has Osteogenesis Imperfecta and how they can live their life normally with the right medical and dental care.

Case #2:

(Picture #1 from the left)This is a panoramic radiograph.

There is posterior unilateral open bite on the left side with increased vertical dimension of the left ramus and body of the mandible

(Picture #2 from the left)This is a PosterioAnterior((PA)) skull radiograph.

How can we differentiate if it is AnterioPosterior or PosterioAnterior?
Only experienced people can tell by the means of magnification and which structures looks magnified more in PA or AP radiographs.
But almost all current machines have the beam come from the back of skull so PA is the smart educated guess since we are in the 21st century. AP projection is only achieved using a free tube skull unit in hospitals now.

How can we differentiate if it is skull radiograph or cephalogram?
Cephalogram is taken by a cephalostat with the ear rods and the ruler, so the cephalogram is a standardized calibrated radiograph, used mainly in orthodontics. While the skull radiograph is taken with any x-ray tube with the head upright but with no regulation for the head position and how far the midsagittal plane is from the film and so on.

In this radiograph we can see the same feature we already mentioned in the first radiograph.

(Picture #3 from the left)This is a lateral cephalogram.

You can notice the two circles (ear rods), the ruler and the piece position the glabella. If we are just taking this radiograph into consideration we could say that if the patient tilted his head to one of the sides, we will end up with similar features >> one thing to look at is the ear rods, if they coincide with each other then the cephalogram is good and the patient didn’t tilt his head and this is the real problem.

Now, taking all 3 radiographs together >> we are looking about a patient with facial asymmetry and unilateral posterior open bite. What is the differential diagnosis??
TMJ abnormality, ankylosis will cause one side to be smaller than the other but in this case one side is bigger than the other. Condylar hyperplasia will cause one side to grow more than the other.

How can we differentiate if it is hyperplasia on this side or hypoplasia on the opposite?? Sometimes if look at the condyles on the radiograph, if the problem was big enough to be noticed morphologically, we will see that one condyle is grossly bigger than the other. But if the problem is not big enough and it is functional problem we can take radionuclide imaging, showing where are the active site of the bone such as Technetium scan, …
(in this case we should take further investigations to decide which one of our differentials are the right one)

[If you are thinking about hemifacial microsomia, it is more of a general problem the mandible , maxilla and the teeth , .. must be affected but this is not the case in our patient and also if we looked back at the PA, there was no "occlusal cant" ( cant is the term used to describe the oblique discontinuation of the occlusal plane when both the maxilla and the mandible is going together either up or down – the mandible and the maxilla followed each other either in hyperplasia or hypoplasia. So it is a feature generalized problem).]
[Another thought is cherubism, but it is bilateral.]
[Fibrous dysplasia is another option, but it is associated with other signs such as ground glass appearance of the bone]

Note: you might see ortho treatment; this is called de-compensation pre-surgical orthodontics. We will talk about this subject in ortho and surgery more... but it is simply to reverse the changes happened to the tissue to adapt the current condition and bring them back to normal before surgery, because we will do the surgery to bring everything back to normal. But in some cases when it is a mild problem we might need the pre-surgical phase. So the sequence in general is like this:
Pre-surgical orthodontics > Surgery > Post-surgical orthodontics.
Note: the nose is not big, the post conchae is much bigger than the anterior one so this is how the nose looks like in a radiograph.

Case #3:

(Picture #1 from the left)This is a panoramic radiograph.

The patient is young and there are some missing teeth. But the main problem in this radiograph is in the morphology; the roots are defected and even some rootless teeth.

The Differential diagnosis; you may think about dentine dysplasia (type1 – radicular type), radiographically this is a great choice but as we said before in real life we'll have medical and dental history of the patient in hand. So a small hint >> this kid was diagnosed with rhabdomayosarcoma in the airway ((is a type of cancer, specifically a sarcoma (cancer of connective tissues), in which the cancer cells are thought to arise fromskeletal muscle progenitors - wiki)) and he was treated with radiotherapy and chemotherapy … one of the differential diagnosis for this presentation is early and generalized radiotherapy and chemotherapy. Why the DD should be early radiotherapy? because if its late the teeth formation will be already finished and we won't see this presentation.

DD of Rootless teeth is either developmental one; dentine dysplasia OR acquired one; early radiotherapy.

[if you are thinking about congenital syphilis because of the screw incisors and what looks like mulberry molars, there is no report that congenital syphilis has rootless teeth and actually these are not how mulberry molars look like, the mulberry molars are cusps of strange look but with right structure enamel covering the dentine but what we see here on the 7's on the right side is missing enamel on some spots, so we can call it hypoplastic pitted molar]
[If you are thinking about taurodontism, one thing about taurodontism that the root length is normal but the chamber is very big and the radicular is tiny, here we have the root length is very small and if you look at the chamber itself and compare it with a the normal size of the chamber you will see that it is normal but because the root length is too small you will see it as if it looks like taurodontism but its not.]

[If you were thinking about osteopetrosis because of more radiopaque appearance of the skull in the 2nd picture which is a PA skull radiograph, actually this is not how osteopetrosis looks like.]

Note: you might notice radiolucency on the right side of the mandible, actually this artifact because of mandibular cavity of the submandibular salivary gland and the patient is not positioned correctly in the midline so we can see it more on the right side.

Case #4:

This is a panoramic radiograph.

There are multiple impacted supernumerary teeth. ((Note: when we are talking about impaction, we should mention if it's associated with any abnormality such as cystic lesion or affecting surrounding structure.)) In this case these impacted supernumeraries are not associated with any pathology. In case of supernumerary teeth we should think about CleidoCranial Dysplasia ((CCD)) and Gardner's Syndrome.

In this case we can see that they are doing interceptive orthodontics to deal with this condition and they are going to pull some of the impacted teeth into the arch later on.

Case #5:

(Picture #1 from the left)This is a Periapical radiograph.

The pulp looks radiopaque here, hard tissue radiopacity, like enamel in dentine. So we are thinking about dense in dente. The main issue to worry about in dense and dente is periapical region and we can't see any lesion in the PA here.

(Picture #2 from the left)This is a CT scan (3D image) , axial section in the upper left corner – the orange line in the reconstructed panoramic, reconstructed panoramic in the upper right corner – the yellow line in axial view, and the rest are cross sections each one represent one of the green line seen in the axial view.

Now if we looked at the Periapical area, we will see a lesion present here but we didn’t see it in the PA because the 2 cortices (buccal and lingual) are not affected _and this is the condition to see a Periapical lesion in a 2D radiograph_ it's like when a thin short guy stand in between on 2 tall fat guys if you look from the front you won't see the short guy in the middle but if you looked to them from the side (the third dimension) you will see the 3 guys. So when a lesion is in between 2 uninvolved cortices you won't see it in a 2D PA radiograph but when using 3D image you will see it in the cross sectional views and the same applies for the caries, you can't see the caries unless there was 50% demineralization in the lesion.
In the picture, you can see the white area is the bone (bony density radiopacity) and the black area is the lesion. We will describe it as; unilocular partially corticated radiolucency that measures 4 cms in the largest diameter apical to the upper left central, causing displacement of the tooth and very minimal effacement (or thinning) of the palatal cortex.

The 3rd picture is showing the tooth after the RCT during follow up visit. And you can notice that lesion which was radiolucent is now more or less radiopaque indicating that the bone is filling the space (this was 6 months after the RCT, it was treated orthograde RCT -conventional- and retrograde -apicectomy- as well)

Case #6:

This is a panoramic radiograph.

First of all, lets count the teeth; these are primary teeth mostly
6 , E , D , C , …….………… , C , D , E
E , D , C , B , A , A , B , C , D , E , 6

In the upper anterior region it’s a bit hard to see whether there is teeth or not because there is the subnasal contact (where the patient puts his nose on while taking the x-ray) but if you look closely you will see that the 4 anterior teeth are missing. So, a great observation that in this case we have retained primary teeth and there is no successors > so we still call it missing teeth and this is severe oligodontia.
A syndrome that you must think about in such a case is > Ectodermal Dysplasia. Clinically we should look at the hair, nails and all the skin appendages.

[If you are thinking about Down syndrome; in Down syndrome there is something wrong sometime they have hyperdontia or taurodontism and maybe hypodontia, but in such a severe case of oligodontia it is not down]

Q; why the primary teeth were formed and the 2 6's but not the permanent teeth?
The ectodermal dysplasia is a multi-factorial disease and there is about 18 type of ectodermal dysplasia so there is a lot of a variation in the presentation. So in this case and in that particular area (the 2 6's) the dental lamina had the potential to proliferate. But in other ectodermal dysplasia cases we might see other teeth present and those are missing.

Case #7:

These are Periapical radiographs.

The 1st is premolar projection, and the 2nd is a lateral-canine projection.

Note: Don’t rush into conclusion once you see the x-ray and say this is odontome. Because there might be another thing with the exact same presentation such as; ameloblastic fibro odontoma.

Looking to the premolar projection, you can notice a well defined mixed density lesion (radiopaque with some radiolucency in the middle) overlapping and mesial to the root of the 1st premolar. It looks like a tooth, so this is a compound odontome. ((Odontome are either compound – tooth-like or complex – haphazard morphology))

Why did we take the lateral-canine projection?
To localize the lesion and determine if it's lingual or buccal to the tooth. So we have to use SLOB rule ((Same Lingual, Opposite Buccal)) with the tube head. OR the Buccal object rule ((buccal object moves with the central beam)). So you have to choose one and stick to it.

In this case, using SLOB rule:
the tube head will go distally when we move from lateral-canine projection to the premolar projection. The odontome was superimposed on the canine and in the premolar projection it was superimposed on the 1st premolar, so it moved same as the tube head (distally) then the object is lingually.
But, using buccal object rule:
the central beam will go mesially when we move from lateral-canine projection to the premolar projection. The odontome was superimposed on the canine and in the premolar projection it was superimposed on the 1st premolar, so it moved against the central beam (distally) then the object is lingually.

Written by: Mohammad H. Bustani
Radiology lecture #3 .. 11.10.2012
Shadi Jarrar
مشرف عام

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تاريخ التسجيل : 2009-08-28
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