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It’s all shades of grey!

8 January, 2018

Author: chris woodgate, ISAS Officer

Hand xray

Nope, I am not talking about a certain book series; I hope you didn’t get your hopes up for something interesting!

What I would like to talk about is quality of image. Yes, I know we have colour doppler, MRI and CT but generally in an imaging service we look at images in ‘shades of grey'.

How then do you assure yourself and others that the images of grey are the best that can be produced?

I am now having to scrape the barrel of knowledge from my student days for some of the theory behind that ‘perfect image’ and, believe me, it is now a long way to the bottom of that barrel.

As I recall, a quality image consists of the right amount of contrast, blur, noise, artefacts, and distortion; sounds like some weird recipe without the benefit of what amounts are required. I think you need the ‘right amount’ of contrast, sharpness rather than blur, reduced noise, as little artefact as possible, and the smallest amount of distortion; hopefully you agree.

So, easy then? Maybe easier said than done.

The modality used makes a difference as to the sensitivity of our shades of grey, eg CT is generally of a higher sensitivity than conventional radiography; it has more shades of grey so soft tissues can be more easily demonstrated. I could expand further but then I would be really boring. Hopefully, you get my drift.

One aspect around image quality that isn’t mentioned so far is the anatomical positioning of the region being imaged. Basically if you image the wrong ‘bit’ or image the ‘bit’ the wrong way, the resultant images may not be diagnostic and we enter into the murky realms of IR(ME)R and, woe betide, a radiation incident. Nobody wants to go there!

How about the fact that the ‘bit’ is attached to a whole which may not want to assist your sharpness quotient by wriggling about, or that the ‘bit’ is surrounded by lots of adipose tissue or metal work which messes up the contrast and the artefact portion of the recipe?

It is all starting to add up to a bit of a nightmare now; did somebody mention the words ‘button pusher’ (don’t get me started)?

I haven’t talked about how you view an image: the amount of ambient light can affect how images on a monitor appear, the quality of the monitor makes a difference, the distance from the monitor and, lastly, if you have left your reading glasses at home, then image blur may be an issue. I could go on, but then it would turn into a ‘proper paper’ rather than a blog and you don’t have time to read that!

How can you assure others you do know and understand about image quality? In the ISAS Imaging Standard there is a whole section dedicated to this in the Clinical Domain with the statement: ‘The service implements and monitors systems to ensure the acquisition of optimal diagnostic quality images.’

Do you know what your service does to ensure optimal diagnostic quality? Do you ever contribute to ensuring that the latest evidence is applied to how you obtain quality images. Do you talk to colleagues and students about your image quality, eg do your reporting radiographers feedback about technical issues?

Why not audit your practice? Your CPD can be updated as you reflect on the findings and make changes or develop practice within your service. Audit isn’t hard. If you look back through your copies of Synergy News I have talked about this previously. Why not give it a try?

I am passionate about our profession. I believe no one can do it better than us; we have to provide the evidence - to demonstrate that we are highly trained professionals who make a difference every day.

Audit can provide you with that evidence and, you never know, maybe you will be the one who writes a paper. Perhaps that can be your New Year’s resolution: to look at image quality and make a difference to your patients, service and profession?

The Imaging Services Accreditation Scheme.

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