1. INTRODUCTION to RADIOLOGY
Michael Maristany, M.D.

2. MAIN ADVANTAGES OF CT OVER MRI
Rapid scan acquisition
Visualization of cortical bone and soft tissue calcifications

4. Multi-Detector (Helical) CT multiple planes of detectors in the gantry
Technical innovation allows
even faster scanning
over a much longer range
with even better image quality
Radiation exposure greater than single-detector CT
“Total body” CT in trauma pts

5. 16
TB Cavity w FB
CT SCAN

6. Normal Trachea Aorta Interlobar Rt interlobar artery artery
Confluent shadow of
right interlobar
artery and superior vein
Aorta
Interlobar
artery
Rt interlobar
artery
Lt interlobar
artery
Normal Cxr
Spine Note:
Density is darker
inferiorly
Rt diaphragm

7. Chest Radiology Pneumothorax: “deep sulcus” sign
Pneumonia or Pulmonary Edema Airspace Disease:
Silhouette Sign & Spine Sign
Pneumoperitoneum: perforated viscus

8. Right pneumothorax

9. Lingular Pneumonia
NL?

10. PNEUMO
PERITONEUM
PLAIN RADIOGRAPH

11. Hounsfield Unit Scale (CT Attenuation)
Gas (Air) -1,000 HU
Fat HU
Water 0 HU
Soft tissue to +100 HU
Bone +1,000 HU

12. Radiographic Densities
Metal Very White
Bone White
Water Gray
Fat Gray-Black
Air Black
Metal is most Radiodense or Radiopaque.
Air is most Radiolucent.

13. HOUNSFIELD UNIT SCALE
Compares attenuation of each tissue through which the x-ray beam passes with the attenuation of WATER.

14. Common Indications for IV Contrast in CT
To visualize blood vessels
(Aortic injury, Abdominal Aortic Aneurysm, Pulmonary Embolus)
To evaluate for primary or metastatic tumor
To evaluate for infection or inflammatory processes
To evaluate for traumatic injury

15. RLQ pain
in a 20 year old male
Appendicitis