Validation of a Novel System for Co-Registration of Coronary Angiographic and Intravascular Ultrasound Imaging.

INTRODUCTION: Intravascular ultrasound (IVUS) is a useful adjunct to guide percutaneous coronary intervention (PCI). Correlating IVUS images with angiographic findings can be challenging. We evaluated the utility of a novel co-registration system for IVUS and coronary angiography. METHODS AND RESULTS: A 3-D virtual catheter trajectory was constructed from separate angiographic imaging runs using bespoke software. Intravascular ultrasound images were obtained using a commercially available mechanical rotational transducer with motorized pullback. Co-registration of ultrasound and angiographic images was then performed retrospectively based on the length of pullback, the 3-D trajectory and the start position of the catheter. Validation was performed in a spherical phantom model and in vivo in the coronary circulation of patients undergoing coronary angiography and intravascular imaging for clinical purposes. 111 paired angiographic and IVUS runs were performed in 3 phantom models. The differences between the reference length and the length measured on the 3D reconstructed path was -0.01 ±â€¯0.40 mm. Intra-observer variability was 0.4%. We enrolled 25 patients in 3 European hospitals and performed 35 co-registration attempts with an 86% success rate. 71 landmarks were selected by the first operator, 68 by the second. Differences between angiographic and IVUS landmarks were -0.22 ±â€¯0.72 mm and 0.05 ±â€¯1.01 mm, respectively. Inter-observer variability was 0.23 ±â€¯0.63 mm. CONCLUSION: We present a novel method for the co-registration of IVUS and coronary angiographic images. This system performed well in a phantom model and using images obtained from the human coronary circulation. CLASSIFICATIONS: Innovation, intravascular ultrasound, other technique.

Multimodality imaging assessment of a caseous calcification of the mitral valve annulus.

Caseous calcification of the mitral annulus (CCMA) is a rare echocardiographic finding. It is commonly misdiagnosed as an abscess, tumor or infective vegetation on the mitral valve. Since it is a benign process, differentiating it from malignant intra-cardiac mass is primordial to avoid unnecessary surgery. Various imaging modalities can be complimentary for definitive diagnosis. We present a case of CCMA in a 71-year-old female patient. Her medical history revealed hypertension, diabetes mellitus, hyperlipidaemia and coronary artery disease. She was referred to our department for coronary catheterization because of angina symptoms upon minimal exertion. The lesion was detected during echocardiography and was defined as a mass of heterogeneous content with calcification points, located at the posterior side of the mitral valve annulus. Restricted motion of the posterior leaflet and the mass effect caused only minimal mitral regurgitation. To establish the correct diagnosis, we performed the full spectrum of noninvasive cardiac imaging modalities. Transesophageal echocardiography identified well-organized, composite lesion with regular edges, markedly calcified margins and more echolucent central portion. A computed tomography (CT) was performed, showing a hyperdense mass with hypodense center and a calcified peripheral rim located at the posterior mitral ring. Cardiac magnetic resonance imaging (MRI) showed that the mass was hypointense with respect to the myocardium in the T1 and T2-weighted sequences and only presented late-phase enhancement in the surrounding capsule. Based on the CT and MRI findings, the diagnosis of CCMA was established. The patient was managed conservatively.