Imaging in Oral and Maxillofacial Pathology

Question 1

How can cleft palate be investigated with imaging?

Answer 1

CBCT

MSCT

MRI

Question 2

How can coronoid and condylar hyper/hypo-plasia, and eagle syndrome be investigated with imaging?

Answer 2

OPG

CBCT

MSCT

Question 3

How are dental anomalies investigated?

Answer 3

Tooth structure development, disturbed eruption, hyper/hypodontia, and hypo/hyperplastic teeth:

PA, OPG, Occlusal, and CBCT

Question 4

How can pulpal, periapical, and periodontal diseases be investigated?

Answer 4

All can be investigated with PA.

PA cyst, osteomyelitis, condensing osteitis, and periodontitis can be also investigated with OPG and CBCT.

Osteomyelitis and periodontitis can also be investigated via MRI

Question 5

How are infections investigated radiographically?

Answer 5

Depends on the infection. TB uses OPG, CBCT, MSCT, MRI, US.

Tonsillolithiasis uses OPG, CBCT, MSCT, and MRI

Question 6

Which oral lesion shows a moth eaten appearance on radiographs?

Answer 6

Squamous cell carcinoma

Question 7

What does PET/CT imaging require?

Answer 7

Provides functional images of radiopharmaceutical radiotracer distributions in the body.

Energy of 511 keV for PET and 100keV for CT

Takes 15 to 30 minutes to perform PET and CT takes 15 to 35 seconds

Question 8

What does SPECT/CT require?

Answer 8

Energy depends on the radio-isotope that is used (> 99mTc) = gamma rays of
140 keV

An area of 30 cm requires about 7 to 14 minutes scanning time
(SPECT precedes the CT)

Question 9

What is the radiation dosage of PET/CT and SPECT/CT?

Answer 9

PET/CT = CT dose (10,000 µSv) + PET (15,000 µSv)

SPECT/CT = SPECT dose (2000 - 5000 µSv) + CT dose (10,000 µSv)

Question 10

How do diagnostic radioactive isotopes create radiation?

Answer 10

They emit gamma rays as they decay.

Question 11

What are the requirements of radiopharmaceuticals used for imaging?

Answer 11

They should have short half-lives so that they can decay at a good rate and emit radiation adequately.

They should have no undesirable biological effects and should be rapidly excreted from the body after the examination.

Question 12

What isotope is used for radionuclide imaging?

Answer 12

In PET scans most common one is F-18 fluoro-deoxy-glucose (FDG).

In SPECT 99mTc is used.

Small volumes of radioactive gasses are often used to assess lung ventillation such as Xe-133, Xe-122, Krypton-81m)

Question 13

How are gamma rays picked up?

Answer 13

Using a gamma camera.