CT Imaging: Basic Technical Concepts

Computed tomography (CT) imaging utilizes various scanning and presentation parameters to generate detailed cross-sectional images of the body. Adjusting these parameters is a balance between image quality and radiation dose. Radiologists and technologists carefully optimize these parameters based on the clinical needs of each individual patient, aiming to achieve a balance between diagnostic image quality and minimizing radiation exposure.
Download these slides at: drive.google.com/file/d/1YfFk...
Chapters:
00:00 - Introduction
01:12 - X-Ray Tubes work like Incandescent Light Bulbs
04:28 - Tube Current
05:08 - Gantry Rotation Time
05:59 - Tube Current-Time Product (mAs)
06:27 - Peak Tube Voltage (kVp)
07:28 - Field of View (FOV)
09:19 - Coverage
11:35 - Acquisition Mode
12:42 - Pitch
13:56 - Reconstruction Algorithm
16:34 - Convolution Algorithm (Kernel)
17:14 - Slice Thickness & Interval
18:47 - Window Width & Level
24:41 - Effects of Scanning & Presentation Parameters
28:10 - CTDIvol & DLP
30:11 - Indications for IV Contrast
31:12 - Adverse Outcomes from IV Contrast
33:37 - Intravenous Accesses
35:28 - IV Contrast Injection Volumes
35:59 - Injection Delays & Bolus Tracking
39:04 - Oral Contrast

[@oldhounddog57]

Love the analogy with Google translate!

[@toyab1213]

Great Lecture

[@NAV866]

Great lecture. Thank you very much.

[@immane75]

Outstanding.

[@AustinPhiri-db6jt]

more enlightening i enjoyed the lecture

[@GntlTch]

Interesting. Thank you for the tutorial. However, @ 16:07 I do not see any difference in noise but the Filtered Back Projection does seem to be a slightly sharper image than the Iterative Reconstruction. Given that the FBP requires less computer power, why is the IR method preferred?

[@radiologyframeworks]

You're welcome! The subtle difference in image noise may be partly obscured because of the compression involved in serving video over KZbin. I'll post a PNG image of this slide in the "Community" tab which may be able to show the subtle difference a little better. Creating a CT image with fewer x-ray photons (i.e. lower radiation dose) is generally associated with slightly lower signal-to-noise on your CT image (i.e. more image noise). Since iterative reconstruction images tend to be less noisy than filtered back projection images, using IR may permit us to get images of similar diagnostic quality as FBP while using slightly less radiation on our patients than if we had used FBP.

[@PaChasoo]

Perfect 🎉

[@monetlecb]

Thank you 😊

[@vinitpatankar7594]

how does the CT slice affect the resolution of the image, 16 slice vs 128 or 256 slice

[@vff90]

Thank you

[@vinitpatankar7594]

Sir I am huge fan of your lectures. Will it be possible for you to make a lecture dedicated to chest CT technical aspects? I am a pulmonologist

[@radiologyframeworks]

Thanks! What particular technical topics did you have in mind?

[@vinitpatankar7594]

particularly for contrast and CT pulmonary angiography.. time sequence for injecting the dye so as to visualise the vessel@@radiologyframeworks

[@NewFacts-nowadays]

Thank you so much for this!

[@laok6174]

Can I have the presentation?

[@radiologyframeworks]

You can find a link to a PDF of all of these slides, just by going to the video and expanding the “Description” section underneath. You’ll find links of this type for almost every one of my talks in the Description area of each video.