**6.2.1 Angiographic diagnosis of preinfundibular course**

The LCA courses on the surface of the subpulmonary infundibulum and sometimes the root of the pulmonary artery, and reaches the interventricular septum at the mid LAD level. Therefore, the LAD coronary artery is relatively short. In RAO and LAO projections, the initial course of the LCA passes anteriorly and upward. The LMCA and the proximal segment of the CX coronary artery form an "eye" with the LMCA as the superior edge and the CX coronary artery as the inferior edge (figure 14).

#### **6.2.2 Angiographic diagnosis of retroinfundibular course**

The LCA courses behind the subpulmonary infundibulum, then in contact with the left ventricular septum, and finally emerges at mid LAD level. Thus, the LAD coronary artery is relatively short. In RAO and LAO projections, the initial course of the LCA passes anteriorly and downward. The upward loop of the CX coronary artery and the LMCA form an "eye". Septal branches arising from the LMCA are an additional clue (figure 15).

intubation and an adequate opacification with regular coronary catheters difficult. An aortography in LAO projection is useful allowing simultaneous visualization of the aorta and the pulmonary trunk. The most common site of drainage is the pulmonary trunk. Multiple collateral vessels coursing the subpulmonary infundibulum and the right ventricle are present, as well as a large collateral circulation through the interventricular septum,

Rare abnormal origins, apart from aorta, contralateral coronary artery and pulmonary

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

The LCA courses on the surface of the subpulmonary infundibulum and sometimes the root of the pulmonary artery, and reaches the interventricular septum at the mid LAD level. Therefore, the LAD coronary artery is relatively short. In RAO and LAO projections, the initial course of the LCA passes anteriorly and upward. The LMCA and the proximal segment of the CX coronary artery form an "eye" with the LMCA as the superior edge and

The LCA courses behind the subpulmonary infundibulum, then in contact with the left ventricular septum, and finally emerges at mid LAD level. Thus, the LAD coronary artery is relatively short. In RAO and LAO projections, the initial course of the LCA passes anteriorly and downward. The upward loop of the CX coronary artery and the LMCA form an "eye".

between the RCA and the LCA.

sometimes incorrect.

**6.1.8 Angiographic diagnosis of other anomalies (type VIII)** 

**6.2.1 Angiographic diagnosis of preinfundibular course** 

the CX coronary artery as the inferior edge (figure 14).

**6.2.2 Angiographic diagnosis of retroinfundibular course** 

Septal branches arising from the LMCA are an additional clue (figure 15).

**6.2 Angiographic diagnosis of ectopic courses** 

artery, are generally never identified by conventional angiography.

Fig. 14. Angiographic view (right anterior oblique projection) showing a preinfundibular course of a left main coronary artery (white arrow) forming an "eye" (star) with the circumflex coronary artery (black arrow).

Fig. 15. Angiographic view (right anterior oblique projection) showing a retroinfundibular course of a left main coronary artery (white arrow) forming an "eye" (star) with the circumflex coronary artery (black arrow). Note a septal branch (arrow head) originated from the left main coronary artery.
