CT Scan Modes Compared (Axial vs Helical)

CT scan modes include both axial and helical scanning. The selection of axial or helical CT depends on the clinical task. In this video we describe the differences between axial and helical scanning and the different conditions that each scan type or scan mode is best for.
CT (Computed Tomography) scanning can be accomplished with multiple different scan modes which have different characteristics. Axial non-volumetric scanning is how CT began where one (or just a few) slices are acquired during each gantry rotation. Traditional helical scanning (some call spiral) has the advantage of being faster than non volumetric axial scanning and also uses data continuously for improved motion robustness. There are then different specialized versions of helical scanning from low pitch scanning for cardiac to high pitch helical scanning for fast volumetric acquisitions. For state of the art systems wide coverage volumetric axial scanning is also an option to cover an entire organ in one rotation. These acquisitions are particularly useful for repeated scanning such as in time resolved angiography or perfusion applications.
For a detailed comparison of the scan modes see our illustrated blog post:
howradiologyworks.com/14040-2/

[@DenMnd]

many thanks, amazing video 👍

[@michaelmontgomery5767]

Canon has the ability to vary the pitch throughout the scan (i.e. Variable Helical Pitch). For body scans the system is set up to have low pitch through the heart and higher pitch thought the body in one run. Great for ED screening.

[@HowRadiologyWorks]

Thanks for mentioning this specific point for chest scanning transitioning to a run off.

[@ranjit12345ful]

Can u please make a video on CT detectors....how does number of detector rows effect the number of slices ....effect on dose to patient such kind of things....thank you dear....God bless for the good work :)

[@HowRadiologyWorks]

Great ideas thanks for the suggestions

[@01rai01]

Can you please explain volume scanning and why it cones/ tapers in the ends of the scan range

[@HowRadiologyWorks]

Sure for wide cone axial scanning at the edge of the volume in the corners there is a shorter range of view angle data collected. So in voxels in the corner this leads to artifacts, that is why the vendors have a mask in the corner of wide coverage systems

[@hayongram]

your video is good :)

[@HowRadiologyWorks]

Thanks 🙏

[@SrikanthNalla17]

Is the patient exposed to more harmful radiation in 128 slices CT scan compared to 32 or 64 slice CT scan??

[@HowRadiologyWorks]

There is not a significant difference in dose efficiency for 64 to 128 rows. The main difference comes from 8 row to 32 row where there is less wasted dose from the penumbra (or edge row effects)

[@user-mf1ie3yo9t]

شكرا لك لدي اختبار فيزياء التصوير المقطعي

[@HowRadiologyWorks]

You’re welcome, good luck on the exam

[@user-mf1ie3yo9t]

@@HowRadiologyWorks bro can you give me answe pls 4 charasterstic of helical scanning This question in the exam after 3 days and I don’t know what’s the answer thank you brother ❤️

[@user-mf1ie3yo9t]

Four charasterstic of helical scanning

[@TheNettforce]

@@user-mf1ie3yo9t sorry is there more to the question as it wasn’t written very specifically? Is it about the acquisition or the images? It may have just been a very broad question where they wanted you to mention 4 things on helical scanning

[@user-mf1ie3yo9t]

@@TheNettforce 4 things in helical scanning we benefit from it I think its General question, I searched for the answer in goggle and my book i don’t get the answer help me pls and think you for your interest you are a good man 🤚🏻❤️

[@talkingtreeswithprofessort8372]

8:08 burn

[@HowRadiologyWorks]

pubmed.ncbi.nlm.nih.gov/34752014/

[@rademm8924]

You talks too fast. Difficult for non native English speakers to understand

[@HowRadiologyWorks]

Sorry Rad , thanks for the input. I will try to talk more clearly. If you rewatch the missed section does that help?

[@SrikanthNalla17]

Rad can watch the video at .75x or .50x speed@@HowRadiologyWorks

[@tesla1161]

Dude. Pause and listen again. He is explaining very well.