**6.2 Angiographic diagnosis of ectopic courses**

As mentioned above, the rate of an accurate diagnosis of ANOCOR is relatively low (<70%) with conventional angiography. Correct angiographic identification of the different possible courses followed by an ectopic vessel is achievable, but requires special training. Numerous examples of misinterpretation of the ectopic course in the literature imply that the rate of erroneous delineation is certainly high in the real life. Before the wide growth of non-invasive imaging, some authors have proposed interesting methods to identify the different anomalous courses of ANOCOR quickly and correctly (Ishikawa & Brandt, 1985, Serota et al., 1990). As the ectopic course of RCA and CX, almost without exception, is typical with a preaortic course and a retroaortic course respectively, these methods are only dedicated to the LCA (LCMA or LAD coronary artery) originated from the opposite sinus or the contralateral artery. The LCA may follow 1 of 4 previously described paths: preinfundibular, retroinfundibular, preaortic and retroaortic. The angiographic criteria used by Serota et al. are based on selective coronary angiograms in the RAO and LAO projections. The method suggested by Ishikawa et al. use angiographic features derived from a selective coronary angiogram in RAO projection and from a 30° RAO ventriculography. The lateral projection may be helpful in some cases. The main features are summarized in table 7. Despite of a meticulous analysis, these methods are sometimes incorrect.
