Anatomical M-Mode

Just a quick tip this time. Many ultrasound users trying some basic cardiology and starting to use M-mode for fractional shortening calculations often struggle to get the correct orientation of the heart in short axis to allow you to get the M-mode line to drop nicely between the papillary muscles. Very often the heart is rotated slightly meaning the M-mode line is never in the right position, resulting in inaccurate calculations. On many scanners there is a solution, although it would be better to try to align the heart correctly when possible…

Anatomic M-Mode or AMM allows you to move the rotation point and angle of the M-mode line to allow you to ‘fit’ it in the correct position between the papillary muscles. Firstly, it’s very important to make sure the short axis view of the left ventricle (LV) is at the correct level and that it’s nice and round. If you can see the white dots of the chordae tendinae at the tip of the papillary muscle you are pretty much at the correct level, if you can only see one papillary muscle correctly or the LV is oval you may need to rotate your probe ever so slightly to make the LV round and make both papillary muscles visible.

Switch on normal M-Mode and use your trackerball to position the ‘blob’ on the M-mode line into the centre of the LV, use the AMM angle control on your scanner to rotate the M-mode line until it’s in the required position. Be aware, the more angle correction you apply the ‘fuzzier’ the M-mode trace will appear, your scanner will also have a limit of AMM angle that can be applied. You can still take relevant cardiac measurements using the analysis package on your scanner and the calculations will be correct as they take into account the AMM angle being applied.

If you have any questions about any of the controls or settings on your scanner, how to optimise the image or even if you are looking for advice on the purchase of additional probes to increase the flexibility of your system, please get in touch. Drop me an email at info@ultrasoundscannertraining.co.uk or call me on 07795322354, I’m always happy to chat and answer your questions.