Objectives:

The aim of this projection is to demonstrate the LAD in a different projection, however due to overlap proximally with the Circumflex and OM1, should only be used to demonstrate the mid / distal LAD. This projection also can demonstrate the mid circumflex well.

Catheter Positioning:

The catheter should be positioned on the left side of the screen and slightly up from the middle before the acquisition is commenced.

Alternatives:

More RAO (eg. RAO 50 / CRA 30):

Separates the OM1 more from the proximal LAD, overlapping it on the Left Main, however the Diagonals are now completely overlapping the LAD, obscuring any potential narrowing’s. The mid / distal Circumflex is opened up more due to further distance from any overlapping LAD branches.

Less RAO (eg. RAO 30 / CRA 30):

This projection demonstrates the mid / distal LAD, however is often overlapped by the Circumflex and OM1.

More CRA (eg. RAO 40 / CRA 40):

Good projection for prox / mid LAD. Foreshortening of the distal LAD. This angle can sometimes be used as an alternative for showing the proximal Circumflex, forming the middle part of the shape of an “M” as it divides into the OM1.

Less CRA (eg. RAO 40 / CRA 20):

Good for mid / distal Circumflex. The LAD is often overlapped by Diagonal branches and the OM1.

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