Optimizing left anterior oblique (LAO) caudal imaging in coronary angiography using the Taguchi method: A phantom study with clinical verification

The aim of this work tried to optimize the spider view of the coronary angiograph for the clinical diagnosis of cardiac artery disease by cardiologists. A qualified spider view in coronary angiography must be exactly a “quasi-spider” image, which can help to diagnose a lesion in left main coronary artery and related regions. Coronary artery phantom was placed in a 75 mm-thick acrylic box to model a 70 kg human thorax. Eighteen groups of various combinations of operating factors of the X-ray facility were organized based on a Taguchi analysis. The six factors that govern the imaging quality of X-ray were (A) whether the X-rays emitted through a filter, (B, C) the Left Anterior Oblique (LAO) and Caudal Angulation (CAU) projection angles, (D) X-ray peak voltage (kVp), (E) X-ray pulse duration and current (mAs) and (F) distance between X-ray source and intensifying plate (SID). The obtained X-ray spider view images of each group were graded to determine the optimal settings; X-ray emitted without filter, 70° LAO, 30° CAU, 110 kVp, 1.5 mAs and 108 cm of SID. X-ray imaging quality optimal result was confirmed based on a clinical diagnosis of 43 patients, to prove the effectiveness of this study.