1. Diagnostic Imaging Required Reading: Pg 125-138
Des Jardins, Clinical Manifestations and Assessment of Respiratory Disease, 4th edition.

2. Types of Diagnostic Imaging Studies
Chest film (CXR)
Computerized Axial Tomography (CT scan)
MRI
Angiography
Nuclear Medicine scans
PET scan

3. CT Scan
An x-ray procedure which combines many x-ray images with the aid of a computer to generate transverse cross-sectional views and at many different angles around the body. These images are processed by a computer to produce cross-sectional pictures of the body. In each of these pictures the body is seen as an x-ray "slice" of the body, which is recorded on a film. This recorded image is called a tomogram. "Computerized Axial Tomography" refers to the recorded tomogram "sections" at different levels of the body.

4. CT Scan
Indications:
When additional diagnostic information is required to investigate and guide treatment. CT are ordered for tumors or masses, fluid, injury (trauma), or other disease process.

5. CT Scans
CT may also used to detect both acute and chronic changes in the lung parenchyma and for detection of airspace disease:
Pneumonia
Pulmonary fibrosis
Emphysema
Lymphadenopathy
Pulmonary embolus
Aortic dissection

6. CT Scan
Contrast media such as Iopamiro, Isovue, Niopam, Solutrast can be given intravenously to help enhance the image and help clarify soft tissue structures.

8. MRI Similar indications to that of CT scans. Advantages
Higher resolution images
No ionizing radiation
More planes of dissection
Transverse (CT)
Coronal
Sagittal

9. MRI Disadvantages Expensive Image acquisition takes much longer
Safety issues (powerful magnet field can cause objects to fly toward the magnet)
6 ft gantry makes patient care difficult

10. MRI Safety Check with Rad. Tech before entering room:
Ferric metal items (attracted to magnets) prohibited
Some electronic items may become non-functional
Plan appropriately for safe patient monitoring
Absolutely do not bring oxygen cylinders near the room.
Plan ahead

11. MRI

12. Fluoroscopy

13. Fluoroscopy
Fluoroscopy is the projection of real-time two dimensional x-ray images. Modern equipment generally projects the image on a television monitor.
“Fluoro”, as it is known is useful for the placement of certain lines.
Injection of contrast dye under fluoro is a procedure known as angiography.

15. Angiography
The injection of contrast dye into vessels.

16. Angiography
Fluoroscopic images can be captured and recorded so one can watch contract dye fill the vascular system of any organ.
This is often done in “Special Procedures”
Heart: Heart Cath Lab.

17. Angiography Advantages Disadvantages
Very specific diagnosis and treatment.
Blocked vessels can be opened and “stented”.
Disadvantages
Angiography is potentially dangerous:
Dye replace blood for a few seconds, and therefore can potentially infarct the tissues

18. Common types of Angiograms
Heart catheterization
Coronary angiography
Right heart ventriculography
Left heart ventriculography
Cerebral angiography
(Extremity angiography (arm or leg)
Renal angiography (kidneys)
Pulmonary angiography (lungs)
Lymphangiography (lymph vessels)
Aortography Retinal angiography

19. Pulmonary Angiogram
Indication:
Pulmonary Embolism
98% sensitive

20. Pulmonary Angiography
Advantage:
Gold standard for diagnosis of pulmonary embolism
Disadvantage:
Higher mortality rate. Possibly an unacceptable risk in unstable patients.

21. Nuclear Medicine
A radioactive element is injected into the patient and tracked with a “gamma camera” with the elements appearing as tiny dots on the screen/film.
Nuclear medicine is distinctly different than contrast since the element used in nuclear medicine does on show up on x-ray like contrast will.

23. Nuclear Medicine: V/Q Scan of Lungs

24. Nuclear Medicine Advantages Disadvantages
No electromagnetic radiation used (no need for practitioners to protect themselves)
Easily tolerated, even in the sickest patients.
Disadvantages
Poor resolution and often not very specific.

25. V/Q Scan
A V/Q (ventilation/perfusion) scan is a test that requires dual induction of radioactive elements at separate intervals:
A radioactive element is injected into the blood stream that has an affinity for pulmonary capillaries
A radioactive element is inhaled, filling the communicating airspaces.

26. V/Q Scan
By superimposing the ventilation study on the perfusion study, probability of pulmonary embolism can be suggested.
A Radiologist reads the study and looks for one or more areas of ventilation with no perfusion.

27. V/Q Scan Two medium to large perfusion defects on V/Q mismatch
Probability of PE: 90%
One medium to large perfusion defect on V/Q mismatch
Probability of PE: 50%
Small perfusion defects
Probability of PE: Low
Source: Family Practice Notebook

28. PET Scan Positron Emission Tomography
Equipment similar to CT scan equipment
Useful in detection of cancer
Useful in diagnosing effectiveness of cancer treatment.