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Right posterior descending coronary artery (Right PDA)

The right posterior descending coronary artery (right PDA) is a terminal branch of the right coronary artery (RCA) in cases of right coronary dominance, the most common coronary dominance pattern (~70%). It runs in the posterior interventricular groove, supplying the inferior third of the interventricular septum, adjacent inferior wall of the left ventricle, and portions of the inferior right ventricle.

The PDA typically arises at the crux of the heart and travels toward the apex, giving off posterior septal perforators. In left dominance, the PDA arises from the left circumflex artery, and in co-dominance, contributions may come from both RCA and LCX. Its anatomy is crucial in coronary artery disease, as PDA stenosis or occlusion often contributes to inferior wall myocardial infarction.

Synonyms

  • Right posterior interventricular artery

  • Right PDA

  • Posterior descending branch of RCA

Function

  • Supplies the inferior interventricular septum via septal branches

  • Perfuses the inferior wall of the left ventricle

  • Contributes to blood supply of the posterior right ventricle

  • Plays a critical role in defining coronary dominance pattern

Branches

  • Posterior septal perforating arteries

  • Small inferior wall branches

MRI Appearance

T1-weighted images:

  • Lumen appears as a signal void (black) along posterior interventricular groove

  • Vessel wall shows low signal, adjacent fat provides contrast

T2-weighted images:

  • Flowing blood creates a signal void

  • In pathology (thrombus, slow flow), lumen may appear altered with intermediate/high signal

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • PDA enhances brightly and homogeneously

  • Post-MI scar or perfusion defect in PDA territory may be visible on delayed enhancement sequences

MRI Non-Contrast Coronary MRA (Cardiac-gated 3D):

  • Depicts PDA as a continuous bright signal tubular structure in posterior interventricular groove

  • Visualizes origin at RCA, course to apex, and septal branches

  • Useful in patients with renal insufficiency where gadolinium cannot be used

CT Appearance

CT Pre-Contrast:

  • PDA appears as a small tubular soft tissue structure; calcifications in vessel wall appear hyperdense

  • Coronary calcium scoring often includes PDA calcification

CT Post-Contrast:

  • PDA enhances with contrast but may be difficult to follow without dedicated coronary protocol

CT Coronary Angiography (CCTA):

  • Gold standard non-invasive modality for coronary imaging

  • Clearly demonstrates PDA origin from RCA (or LCX in left dominance), course in posterior interventricular groove, and distal branching

  • Multiplanar and 3D reconstructions define stenosis, occlusion, plaque burden, and dominance pattern

  • Detects atherosclerotic disease, anomalous origins, or post-stent/graft evaluation

CT images

right posterior descending coronary artery ct axial anatomy image -img-00000-00000

CT images

right posterior descending coronary artery ct axial anatomy image -img-00000-00000_00001