1. Radiology Course CT scan
Ghione Emanuele
Prof. Fabrizio Calliada

2. History
CT was introduced in 1972 born from two separated research groups A.M.Cormack (american physicist) and G.N.Hounsfield (british electronic engineer) in the 60s
Both won in 1979 the Nobel prize.
… It is said that revenues from the sales of The Beatles records in the 1960s helped fund the development of the first CT scanner at EMI

4. Definition CT
CT = Computed Tomography is a diagnostic technique which exploits ionizing radiations (X ray) It uses a computer that takes data from several X-ray images of structures inside a human's body and converts them into pictures on a monitor. Tomography is the process of generating a 2-dimensional image of a slice or section through a 3-dimensional object.

5. How is it made?

6. 6

7. 1) X ray rotating tube 7

8. 2) Multiple rows of Detectors8

9. 3) The Gantry 9

10. 4) The bed!!! (of course! :-) 10

12. What kind of images I can get?
IT’S A SLICE!!!

13. 2D coronal plan
On the traditional radiogram in a single image represent the whole segment of the examined body
Anatomic structures superimpose and may have no differences on density on the plain film. 13

14. CT scan - Body on slices 2D axial plan 14
All these projections are mathematically integrated to reconstruct a slice of the body.
Every pixel of the image has an intensity corresponding to a density
All the anatomic structures are visible without problems of superimposement
The tissue density is measured with the Hounsfield units
2D axial plan 14

15. HOUNSFIELD UNIT 15

16. 1 2 3 Evolution of CT scan Computed Axial Tomography (CAT scan)
Spiral CT
Multi-slice (multi-detector CT) 2 3

17. CAT (Computed Axial tomography)
•Scanners were used to acquire sequential layers
• They provided axial images of the han body
"slices" of the human body
• The exam is slow and complex

18. • CAT (computed axial tomography) • Spiral CT (single detector)
• Computed tomography (CT Scan)
• CAT (computed axial tomography)
• Spiral CT (single detector)
• Concept of body volume

19. Single slice
One Rotation - One Image

20. • CAT (computed axial tomography) • Spiral CT (single detector)
• Computed tomography (CT Scan)
• CAT (computed axial tomography)
• Spiral CT (single detector)
• Multidetector CT (Multi Slice)
• 16 layers
• 64 layers
• 128 layers
• 600 layers

21. Multi slice
One Rotation – Multiple Images

22. Multi slice

23. Contrast agent, or not contrast agent, that is the question…
Brain / basal skull
• vascular disease (ischemia-bleeding), trauma,
infections.
Brain / Skull with MDC
• Vascular Pathology (study of intracranial vessels)
• Pathology Oncology
• Infectious pathology (abscesses)
Abdomen baseline
• Urinary stones
Abdomen with MDC
• Pathology of cancer parenchyma
• Liver, pancreas, spleen, kidneys, adrenal glands
• Vascular Pathology (study aorta; study
mesenteric vasculature)
• Pathology of the peritoneum
• Pathology of the pelvis (oncology)
Chest baseline
• HRCT (high-resolution CT)
Chest with MDC
• Pathology of lung cancer (primary and
secondary)
• Vascular Pathology (study of the pulmonary vessels,
study aorta)
• Pathology heart (coronary study)
Arterial and venous vascular system
(only with MDC)
• Arts
• Aorta
• Mesenteric vessels
• Intracranial vessels

24. Brain CT Scan (without contrast)

25. Brain CT Scan (with contrast)

26. Lung CT Scan (without contrast)
Pleural effusion
Pericardic effusion

27. Lung CT Scan (with contrast)
Lung carcinoma MDC

28. Abdomen CT Scan (without contrast)
Kidney stones

29. Abdomen CT Scan (with contrast)

30. CT Scan CONTRAST PHASES
Arterious
- manual sec
- automatic
2) Venous or portal
- 90 sec
3) Late or corticomedullary
- 3-5 min

31. 1) Arterious PHASE (ANGIO CT)
how to make it
- scan during transit of contrast media in artery

32. 2) Venous PHASE How to make it
for evaluation of the venous spleno-portal axis
for evaluation of the parenchimas of the abdomen

33. 3) Late - Corticomedullary PHASE
Evaluation of kidneys, excretory system and urinary bladder
washout of some tumors (e.g. HCC)
Adrenal gland behaviour
Better visualization of peripheral veins

34. Thank you!!!