Anatomical evaluation of the internal mammary vessels based on magnetic resonance imaging (MRI)

Introduction: The rib-sparing technique to access the internal mammary vessels for microanastomosis is the current practice in our hospital nowadays. This study is performed to analyse the best intercostal space to expose those vessels.

Patients and methods: Magnetic resonance imaging (MRI) of the chest wall of 133 women was evaluated. The Schwabegger classification (representing the anatomical variation), the intercostal space between ribs two, three and four, and the surface of the internal mammary artery and veins in the second and third intercostal space were determined on multiplanar reconstructed T2-weighted images.

Results: In more than half of the cases, the anatomy followed Schwabegger variation two; one lateral artery and one medial vein were symmetrical. If a second vein was present, the bifurcation was most commonly in the third intercostal space. The second intercostal space above the mammary vessels was significantly wider than the third one. The surface of the artery and vein(s) was significantly larger in the second intercostal space.

Conclusion: In most clinical situations, the second intercostal space is most likely the best approach to the internal mammary vessels for microanastomosis using a rib-sparing technique because of wider intercostal space and larger artery and vein.