Radiology Flashcards
Describe the aims of taking a radiograph
- Identify presence or absence of abnormality or disease
- Provide information on nature and extend of abnormality or disease
- Enable formation of differential diagnosis
- Aid treatment planning
What are 3 commonly used intra oral radiographic views?
- IOPA
- Bitewing
- Occlusal
What are 3 commonly used extra oral radiographic views?
- Orthopantomogram (OPT)
- Lateral ceph
- Maxillofacial radiographs
Describe an IOPA radiograph
Intraoral technique designed to give detailed information on individual teeth and tissues around the apices
What are 6 indications for taking an IOPA?
- Apical pathology
- Periodontal assessment
- Unerupted tooth
- Root morphology
- Endodontics
- Implants
Name 2 advantages of IOPAs
- Low radiation dose
2. Good quality images
Name 4 disadvantages of IOPAs
- Increased cross infection risk
- Some patients cannot tolerate holder
- Positioning inaccuracies
- Limited view
Describe the normal anatomy seen on all IOPA
- Periodontal ligament (radiolucent area between root and lamina dura)
- Lamina Dura (thin dense bone surrounding tooth)
- Cancellous bone (radiodense plates and rods)
What is the clinical significant of seeing the nasopalatine foramen on an IOPA?
It is a site of common cyst formation
Describe how the maxillary sinus may appear in an IOPA
- The floor is thin radio-opaque line in molar / premolar region
- Sinus is radiolucent
What is a bitewing radiograph designed to do?
Show the crowns of premolar and molar teeth on one side of the jaw
Describe 4 indications for the use of bitewing radiographs
- Detection of dental caries
- Monitoring progression of caries
- Assessment of existing restorations
- Assessment of periodontal status
What are occlusal radiographs?
Intraoral technique using film placed on the occlusal plane
What are the 3 classifications of maxillary occlusals?
- Upper anterior 65 - 70 degrees (standard)
- Upper oblique 65 - 70 degrees
- Vertex (Upper 90 degrees - No longer used)
What are the 3 classifications for mandibular occlusals?
- Lower 90 degrees (true occlusal)
- Lower 45 degrees (standard)
- Lower oblique (centred off to one side)
Name 4 indications for upper standard occlusal radiographs
- Periapical assessment
- Detection of supernumeraries, unerupted canines and odontomes
- Pathology anterior maxillary area
- Midline view for parallax
Name 4 indication for upper oblique occlusal radiographs
- Periapical upper posterior teeth
- Evaluation of cysts in posterior maxilla
- Position of roots displaced into antrum
- Fractures of posterior teeth / bone
Name 4 indications of lower anterior 90 degree occlusal radiographs
- Detection of submandibular duct calculi
- Bucco/lingual position of unerupted mandibular teeth
- Bucco/lingual expansion of mandible by cysts and tumours
- Assessment of fracture displacement in horizontal plane
Name 3 indications of lower standard occlusal radiographs
- Periapical assessment of lower incisors
- Evaluation of extent of cysts and tumours in anterior mandible
- Assessment of fracture displacement in vertical plane
Name 4 indications of lower oblique occlusal radiographs
- Detection of calculi in posterior submandibular duct or gland
- Bucco/lingual position of lower third molars
- Bucco/lingual extent of mandible by cysts and tumours in posterior part or angle of mandible
- Assessment of fracture displacement in horizontal plane
Describe the components of normal anatomy seen in maxillary occlusal radiographs
- Nasal septum
- Nasal fossa
- Anterior nasal spine
- Nasopalatine foramen
- Inferior turbinate
- Maxillary antrum
Describe the components of normal anatomy in mandibular occlusal radiographs
- Tongue
- Body of mandible
- Mental ridge
- Mental foramen
- Genial tubercles
Describe 3 advantages of OPTs
- Shows all teeth and structures on one film
- Relatively simple technique
- Low radiation dose
Describe 6 indications of OPTs
- Pathology of jaws
- Fractured mandibles
- Wisdom teeth assessment
- Periodontal status
- Orthodontic assessment
- Assessment for implants
What are 4 possible air shadows which may be seen on OPTs?
- Nasal cavity
- Nasopharynx
- Oropharynx
- External auditory canal
What are 4 possible soft tissue shadows which may be seen on OPTs?
- Soft palate
- Pinna
- Epiglottis
- Posterior pharyngeal wall
Describe the radiographs taken for suspected fractured mandible
OPT and posterior-anterior mandible
Describe the radiographs taken for suspected fractured zygoma
15 and 30 degree occipitomental radiographs
What 3 ways may radiographic errors occur?
- Technique
- Exposure
- Processing
Describe 4 ways in which technique can lead to errors in radiographs
- Patient preparation
- Film placement
- Incorrect angle
- Misalignment of beam to film
Describe how patient preparation may lead to radiographic
- Failure to remove jewellery / dentures
- Blurring due to patient movement
Describe how film placement may lead to radiographic
- Area of interest not shown
- Only apex or crown shown (IOPAs)
- Distortion due to film bending
Describe how incorrect angle may lead to radiographic
- Elongated or shortened teeth (vertical)
- Overlapping (horizontal)
Describe how misalignment of beam to film may lead to radiographic
Cone cut or coned off
Describe exposure errors in taking radiographs
Excessive / not enough exposure time, KvP, MA or combination fo these
Name 4 ways processing can be influenced which may lead to errors
- Time and temperature
- Chemical contamination
- Film handling
- Light
Describe 5 advantages of digital imaging
- No chemical processing waste
- Elimination of radiographic film
- Elimination of darkroom and automatic processing equipment
- Less radiation dose to patient
- Instant viewing of images
Describe 5 disadvantages of digital imaging
- Initial set up costs
- Sensors may be bulky for patients
- Need computer and WiFi network
- Lack of hard copy
- Integration of software into practice can be difficult
Describe the components of a radiography report
- Name, DOB, hospital number, date taken
- Type of radiograph
- Quality standard
- Area shown and general features
- Detailed description of salient features
Describe the acronym used to describe radiographs
LESION
- Location - Edge - Size - Internal - Other structures - Number
What is a radiolucency / radiodensity on a radiograph?
- Radiolucencies allow passages of radiant energy and appear dark
- Radiodensities are resistant to passage of radiant energy and appear white
Describe the terms well defined and poorly defined
- Well defined shows sharp boundary which allows edge of lesion to be traced
- Poorly defined shows gradual transition between normal and abnormal bone
Describe the terms corticated, unilocular and multilocular when describing radiographic lesions
- Corticated is thin lining of bone surrounding lesion
- Unilocular is having single compartment
- Multilocular is having many compartments
Name 4 different imaging modalities
- CT
- CBCT
- Ultrasound
- MRI
Name 4 different imaging modalities
- CT
- CBCT
- Ultrasound
- MRI