Three-dimensional coronary reconstruction from routine single-plane coronary angiograms: in vivo quantitative validation

Angiography and optical coherence tomography derived shear stress: are they equivalent in my opinion?

Advances in image reconstruction using either single or multimodality imaging data provide increasingly accurate three-dimensional (3D) patient's arterial models for shear stress evaluation using computational fluid dynamics (CFD). We aim to evaluate the impacts on endothelial shear stress (ESS) derived from a simple image reconstruction using 3D-quantitative coronary angiography (3D-QCA) versus a multimodality reconstruction method using optical coherence tomography (OCT) in patients' vessels treated with bioresorbable scaffolds. Seven vessels at baseline and five-year follow-up of seven patients from a previous CFD investigation were retrospectively selected for a head-to-head comparison of angiography-derived versus OCT-derived ESS. 3D-QCA significantly underestimated the minimum stent area [MSA] (-2.38mm2) and the stent length (-1.46 mm) compared to OCT-fusion method reconstructions. After carefully co-registering the region of interest for all cases with a sophisticated statistical method, the difference in MSA measurements as well as the inability of angiography to visualise the strut footprint in the lumen surface have translated to higher angiography-derived ESS than OCT-derived ESS (1.76 Pa or 1.52 times for the overlapping segment). The difference in ESS widened with a more restricted region of interest (1.97 Pa or 1.63 times within the scaffold segment). Angiography and OCT offer two distinctive methods of ESS calculation. Angiography-derived ESS tends to overestimate the ESS compared to OCT-derived ESS. Further investigations into ESS analysis resolution play a vital role in adopting OCT-derived ESS.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

Clinical expert consensus document on quantitative coronary angiography from the Japanese Association of Cardiovascular Intervention and Therapeutics

Quantitative coronary angiography (QCA) remains to play an important role in clinical trials and post-marketing surveillance related to the safety and efficacy of new PCI devices. In this document, the current standard methodology of QCA is summarized. In addition, its history, recent development and future perspectives are also reviewed.

Three-dimensional reconstruction and NURBS-based structured meshing of coronary arteries from the conventional X-ray angiography projection images

Despite its two-dimensional nature, X-ray angiography (XRA) has served as the gold standard imaging technique in the interventional cardiology for over five decades. Accordingly, demands for tools that could increase efficiency of the XRA procedure for the quantitative analysis of coronary arteries (CA) are constantly increasing. The aim of this study was to propose a novel procedure for three-dimensional modeling of CA from uncalibrated XRA projections. A comprehensive mathematical model of the image formation was developed and used with a robust genetic algorithm optimizer to determine the calibration parameters across XRA views. The frames correspondences between XRA acquisitions were found using a partial-matching approach. Using the same matching method, an efficient procedure for vessel centerline reconstruction was developed. Finally, the problem of meshing complex CA trees was simplified to independent reconstruction and meshing of connected branches using the proposed nonuniform rational B-spline (NURBS)-based method. Because it enables structured quadrilateral and hexahedral meshing, our method is suitable for the subsequent computational modelling of CA physiology (i.e. coronary blood flow, fractional flow reverse, virtual stenting and plaque progression). Extensive validations using digital, physical, and clinical datasets showed competitive performances and potential for further application on a wider scale.

Vessel centerline reconstruction from non-isocentric and non-orthogonal paired monoplane angiographic images

PURPOSE

Three-dimensional reconstruction of a vessel centerline from paired planar coronary angiographic images is critical to reconstruct the complex three-dimensional structure of the coronary artery lumen and the relative positioning of implanted devices. In this study, a new vessel centerline reconstruction method that can utilize non-isocentric and non-orthogonal pairs of angiographic images was developed and tested.

METHODS

Our new method was developed in in vitro phantom models of bifurcated coronary artery with and without stent, and then tested in in vivo swine models (twelve coronary arteries). This method was also validated using data from six patients.

RESULTS

Our new method demonstrated high accuracy (root mean square error = 0.27 mm or 0.76 pixel), and high reproducibility across a broad imaging angle (20°-130°) and between different cardiac cycles in vitro and in vivo. Use of this method demonstrated that the vessel centerline in the stented segment did not deform significantly over a cardiac cycle in vivo. In addition, the total movement of the isocenter in each image could be accurately estimated in vitro and in vivo. The performance of this new method for patient data was similar to that for in vitro phantom models and in vivo animal models.

CONCLUSIONS

We developed a vessel centerline reconstruction method for non-isocentric and non-orthogonal angiographic images. It demonstrated high accuracy and good reproducibility in vitro, in vivo, and in clinical setting, suggesting that our new method is clinically applicable despite the small sample size of clinical data.

Comparison of 3-dimensional and 2-dimensional quantitative coronary angiography and intravascular ultrasound for functional assessment of coronary lesions

BACKGROUND

Three-dimensional quantitative coronary angiography (3D-QCA) reportedly allows more accurate delineation of true vessel geometry when compared with standard two-dimensional (2D) QCA and has been validated by intravascular ultrasound (IVUS). This study sought to compare diagnostic efficiency of 2D- and 3D-QCA, and IVUS in identifying hemodynamically significant coronary stenoses as determined by fractional flow reserve (FFR).

METHODS

Forty-two lesions in 40 patients were assessed by FFR, IVUS, and 2D- and 3D-QCA. Correlations between FFR values and anatomical parameters obtained by 2D- and 3D-QCA and IVUS were analyzed. The receiver operating characteristic (ROC) curves were used to compare the diagnostic accuracy of the parameters for predicting FFR≤0.80.

RESULTS

Mean FFR value was 0.75±0.13. FFR≤0.80 was observed in 28 lesions (67%). Of IVUS measurements, minimum lumen area (MLA) well correlated with FFR values (r=0.71, p<0.001). Of 3D- and 2D-QCA measurements, minimum lumen diameter (MLD) correlated best with FFR values (r=0.79, p<0.01; r=0.68, p<0.01, respectively), followed by MLA (r=0.76, p<0.01; r=0.67, p<0.01, respectively). The area under the ROC curve for 3D-QCA MLD was greater than those for 2D-QCA MLD (p=0.03) and 2D-QCA MLA (p=0.03). On the other hand, the AUC for 3D-QCA MLD, 3D-QCA MLA, and IVUS MLA were not significantly different.

CONCLUSIONS

3D-QCA is more useful than 2D-QCA and possibly comparable to IVUS in the assessment of functional stenosis severity. When FFR is not available, 3D-QCA MLA and MLD may assist in the assessment of functional severity of intermediate lesions.

Coronary CT angiography in calcified coronary plaques: Comparison of diagnostic accuracy between bifurcation angle measurement and coronary lumen assessment for diagnosing significant coronary stenosis

BACKGROUND

To investigate the diagnostic value of coronary CT angiography (CCTA) by bifurcation angle measurement in the assessment of calcified plaques compared to conventional coronary lumen analysis.

METHODS

Fifty-three patients with calcified plaques identified on CCTA in the left coronary artery were included in the study. Minimal lumen diameter (MLD) and bifurcation angle between the left anterior descending (LAD) and left circumflex (LCx) arteries were measured and compared between CCTA and invasive coronary angiography (ICA), while the areas under the curves (AUCs) by receiver-operating characteristic curve analysis (ROC) were compared between CCTA and ICA with regard to the diagnostic value of using bifurcation angle as a criterion.

RESULTS

On a per-vessel assessment, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and 95% confidence interval (CI) with the use of bifurcation angle for determining coronary stenosis were 100% (86%, 100%), 79% (59%, 92%), 81% (62%, 92%), and 100% (85%, 100%) for CCTA, and 100% (86%, 100%), 82% (63%, 94%), 83% (65%, 94%), and 100% (85%, 100%) for ICA, respectively. While the sensitivity and NPV remained unchanged, the specificity and PPV of CCTA by MLD were 33% (21%, 47%) and 43% (31%, 56%). The AUCs by ROC curve analysis for CCTA and ICA bifurcation angle measurements demonstrated no significant difference (p>0.05, 0.79 vs 0.86, and 0.70 vs 0.68 at the LAD and LCx assessment, respectively).

CONCLUSION

Coronary CT angiography by bifurcation angle measurement shows significant improvement in the diagnosis of calcified plaques with diagnostic value comparable to invasive coronary angiography.

Three dimensional quantitative coronary angiography can detect reliably ischemic coronary lesions based on fractional flow reserve

Conventional coronary angiography (CAG) has limitations in evaluating lesions producing ischemia. Three dimensional quantitative coronary angiography (3D-QCA) shows reconstructed images of CAG using computer based algorithm, the Cardio-op B system (Paieon Medical, Rosh Ha'ayin, Israel). The aim of this study was to evaluate whether 3D-QCA can reliably predict ischemia assessed by myocardial fractional flow reserve (FFR) < 0.80. 3D-QCA images were reconstructed from CAG which also were evaluated with FFR to assess ischemia. Minimal luminal diameter (MLD), percent diameter stenosis (%DS), minimal luminal area (MLA), and percent area stenosis (%AS) were obtained. The results of 3D-QCA and FFR were compared. A total of 266 patients was enrolled for the present study. FFR for all lesions ranged from 0.57 to 1.00 (0.85 ± 0.09). Measurement of MLD, %DS, MLA, and %AS all were significantly correlated with FFR (r = 0.569, 0609, 0.569, 0.670, respectively, all P < 0.001). In lesions with MLA < 4.0 mm(2), %AS of more than 65.5% had a 80% sensitivity and a 83% specificity to predict FFR < 0.80 (area under curve, AUC was 0.878). 3D-QCA can reliably predict coronary lesions producing ischemia and may be used to guide therapeutic approach for coronary artery disease.

Three-dimensional quantitative coronary angiography and quantification of jeopardised myocardium to predict functional significance of intermediate coronary artery stenosis

AIMS

Despite the fact that fractional flow reserve (FFR) is better than angiography in guiding PCI, in the real world the choice to perform PCI is generally based on angiography. Three-dimensional quantitative coronary angiography (3D-QCA) may increase the accuracy of angiography, especially in intermediate coronary artery stenosis (ICAS). The aim of the study was to assess the best cut-off values of area stenosis % (AS%) and the extent of jeopardised myocardium for predicting FFR and for excluding the need to perform FFR.

METHODS AND RESULTS

FFR, AS% and Myocardial Jeopardy Index (MJI) were assessed in 211 ICAS. MJI (=-0.36; p=0.001), AS% (=-0.35; p=0.001) and presence of a chronic total occlusion (CTO) (=-0.15; p=0.01) were independent predictors of FFR. In patients without CTO (174 lesions), the best cut-offs for the detection of FFR ≤0.80 for AS% and MJI were 61% (AUC=0.76; p<0.001) and 30% (AUC=0.71; p<0.001), respectively. More importantly, the cut-offs of AS% safely to exclude (100% sensitivity) an FFR ≤0.80 were 40% (AUC=0.85, p<0.001) for an MJI ≥30% and 50% (AUC=0.70, p<0.04) for an MJI <30%, respectively.

CONCLUSIONS

AS%, MJI and the presence of a CTO predicted FFR values. 3D-QCA in addition to MJI allows the safe exclusion of FFR ≤0.80, limiting FFR assessment to doubtful cases with considerable reduction of costs.

Three-dimensional intravascular ultrasound evaluation of carina and plaque shift at the distal left main coronary artery bifurcation after treatment with a one-stent cross-over technique

OBJECTIVE

To assess the geometrical changes in the distal left main coronary artery (LMCA), left anterior descending (LAD), and left circumflex (LCX) that occur after a distal LMCA lesion is treated using a one-stent cross-over strategy.

BACKGROUND

Morphological changes after stent implantation into distal LMCA lesions are not fully understood.

METHODS

We used pre- and postintervention three-dimensional intravascular ultrasound of both the LAD and LCX as well as of the LMCA to evaluate distal LMCA lesions after a 1-stent cross-over strategy. In 38 distal LMCA bifurcation lesions, cross-sectional measurements were performed every 1 mm over a 5-mm segment in the LAD and LCX distal to the carina and over the entire LMCA proximal to the carina.

RESULTS

The increase in lumen volume correlated with the increase in external elastic membrane volumes: R = 0.917, P < 0.001, in the LMCA and R = 0.785, P < 0.001, in the LAD with no decrease in plaque volume except at the distal end of the LMCA (P = 0.081) and at the LAD carina (P = 0.11). The LCX lumen area decreased significantly at the LCX carina from 5.9 ± 2.0 mm(2) to 5.3 ± 1.9 mm(2) (P < 0.01); however, the response was variable from a 4.0 mm(2) decrease to a 1.8 mm(2) increase in lumen area. While the change in LCX lumen area at the carina correlated with the change in vessel area (R = 0.791, P < 0.001), there was also a small increase in plaque area at the LCX carina from 6.4 ± 2.9 mm(2) to 6.8 ± 2.9 mm(2) (P < 0.01).

CONCLUSIONS

LMCA bifurcation lumen changes after cross-over single-stent implantation were determined primarily by conformational changes in vessel geometry.

Comparison of two- and three-dimensional quantitative coronary angiography to intravascular ultrasound in the assessment of intermediate left main stenosis

Angiographic evaluation of intermediate left main coronary artery stenosis (LMS) is often limited. Three-dimensional (3D) quantitative coronary angiography has recently developed to overcome 2-dimensional (2D) quantitative coronary angiographic (QCA) limitations. In patients with angiographically intermediate LMS, we investigated whether 3D quantitative coronary angiography was superior to 2D quantitative coronary angiography in predicting the presence of a significant LMS, defined as a minimum luminal area <6 mm(2) at intravascular ultrasound (IVUS). 2D and 3D quantitative coronary angiography were compared in their measurements of minimum luminal area, percent area stenosis, minimum luminal diameter, and percent diameter stenosis and in their prediction of an IVUS minimum luminal area <6 mm(2). In total 58 target lesions were interrogated, 25 (43%) of which had an IVUS minimum luminal area <6 mm(2). Correlation between 3D-QCA minimum luminal area and IVUS minimum luminal area was stronger than the correlation between 2D-QCA minimum luminal area (or minimum luminal diameter) and IVUS minimum luminal area (R = 0.67, p = 0.0001, and R = 0.40, p = 0.001, respectively, p = 0.04 for comparison). To predict IVUS minimum luminal area <6 mm(2), the most accurate 2D-QCA measurement was minimum luminal diameter (area under curve 0.81, cutoff 2.2 mm, p = 0.0001), and the most accurate 3D-QCA measurement was minimum luminal area (area under curve 0.86, cutoff 5.6 mm(2), p = 0.0001). 2D-QCA percent diameter stenosis did not significantly predict IVUS minimum luminal area <6 mm(2) (area under curve 0.56, cutoff 38%, p = 0.45). In conclusion, the accuracy of quantitative coronary angiography in predicting LM IVUS minimum luminal area <6 mm(2) is limited. When IVUS is not available or contraindicated, 3D quantitative coronary angiography may assist in the evaluation of intermediate LMS. Among 2D-QCA parameters, minimum luminal diameter is more accurate than percent diameter stenosis in predicting significant LMS.

Transient impairment of vasomotion function after successful chronic total occlusion recanalization

OBJECTIVES

The aim of our study was to assess coronary vasomotion after successful revascularization of chronic total occlusion (CTO).

BACKGROUND

It is largely unknown whether the recovery of anterograde flow after CTO recanalization with drug-eluting stent implantation affects vascular function in distal coronary segments.

METHODS

One hundred consecutive CTOs successfully treated with drug-eluting stents underwent coronary diameter measurement after intracoronary nitroglycerin injection 5, 20, and 35 mm distal to the stented coronary segment using 3-dimensional quantitative coronary angiography. In a subgroup of 14 patients, coronary vasomotion was tested in distal segments: incremental atrial pacing for endothelium-dependent cases; and intracoronary nitroglycerin injection for endothelium-independent cases. In another subgroup of 13 patients, distal vessels were assessed by intracoronary ultrasounds.

RESULTS

Vessel diameters significantly increased at follow-up as compared to baseline values (2.0 ± 0.52 mm vs. 2.25 ± 0.50 mm, 1.76 ± 0.49 mm vs. 2.05 ± 0.58 mm, 1.54 ± 0.53 mm vs. 2.04 ± 0.58 mm, at each segment analyzed; p < 0.001). At baseline, distal segments failed to respond to both endothelium-dependent and -independent stimuli. At follow-up, atrial pacing induced vasoconstriction, whereas nitroglycerine administration resulted in significant vasodilation (p < 0.05). Intracoronary ultrasounds failed to show changes of the cross-sectional area of distal segments at follow-up angiography.

CONCLUSIONS

Recanalization of CTO is followed by a hibernation of vascular wall at distal coronary segments that fail to respond to endothelium-dependent and -independent stimuli. Distal vessel diameter increases over time in the absence of positive remodeling and in spite of persistent endothelial dysfunction. This severe impairment of vasomotor tone after CTO reopening suggests that intracoronary ultrasound assessment is of paramount importance for the selection of stent size.

Anatomic features of the left main coronary artery and factors associated with its bifurcation angle: a 3-dimensional quantitative coronary angiographic study

OBJECTIVE

To assess the anatomic characteristics of the left main coronary artery (LM), and the relation between anatomic and clinical factors and the LM bifurcation angle (BA) using a novel, three dimensional quantitative coronary angiography (3D QCA) software.

BACKGROUND

Percutaneous intervention of the LM is a therapeutic option in selected patients with coronary artery disease (CAD). The anatomic features of the LM and its BA are determinants of procedural success and clinical outcome. However, those features and the factors that may affect the LM BA have not been fully described.

METHODS

The LM anatomy was evaluated from angiograms of 203 patients (age = 66 ± 11 years, 31% female) with and without LM CAD using 3D QCA analysis (IC-PRO, Paieon, Israel). LM size as well as the proximal BA (between LM and LCX) and the distal BA (between left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX)) were measured in end-diastole. Angiographic and clinical findings were also recorded.

RESULTS

133/203 patients (65%) had no LM CAD. 3D QCA analysis demonstrated significant variability in the anatomy of the normal LM, including the LM branch vessels (LAD, LCX) diameter, and the LM BA. Among the 70 patients with LM CAD, 44 had distal LM disease. Importantly, patients with distal LM CAD had narrower proximal BA and a wider distal BA. Multivariate analysis (adjusted for clinical and anatomic variables) identified female sex (P = 0.02), trifurcation anatomy (P = 0.009), age > 75 years (P = 0.0009), and LM length > 12 mm (P = 0.001) as independent associates of the proximal BA. Independent associates of the distal BA were: trifurcation anatomy (P = 0.001), LM length > 12 mm (P < 0.0001), age > 75 years (P = 0.004), and a history of coronary bypass surgery (P = 0.04).

CONCLUSIONS

The current study demonstrates significant variability in the anatomy of the LM. The LM BA differs between patients with and without distal LM CAD, and both anatomic and clinical factors may affect the LM BA. Our findings also emphasize the possible usefulness of 3D QCA in the assessment of the LM.

Novel QCA methodologies and angiographic scores

Coronary angiography remains the gold-standard method for evaluating coronary artery disease and interventional treatments. As percutaneous coronary interventions have advanced, quantitative coronary angiography (QCA) techniques have also evolved in order to provide more accurate assessments of these therapies. Improvements have been made at each step of the QCA process from image acquisition to vessel analysis. In addition, multiple scoring systems have been developed in order to utilize QCA data, both alone and in conjunction with clinical factors, to better stratify patient risk. This article will review the recent advancements in QCA techniques and outcome prediction models.

Percutaneous aortic valve implantation using novel imaging guidance

Thorough imaging of the aortic valve and related structures is highly important before and during percutaneous valve implantation. However, imaging modalities currently used in the catheterization room, namely, conventional aortography and transesophageal echocardiography are limited in guiding the precise valve placement during the implantation procedure. A novel real-time imaging modality capable of three-dimensional reconstruction of the ascending aorta has recently been introduced (CardioOp-THV, C-THV, Paieon Inc., Park Afek, Israel). We applied this system during a complex procedure of percutaneous aortic valve implantation in a patient with severe aortic tortuosity, large aortic-valve angulation, and asymmetric septal hypertrophy. We found the guidance system very helpful not only for accurate positioning of the valve but also for selecting the optimal projection for valve implantation, selecting the prosthetic valve size, and evaluating the results after deployment.

Real-time 3D imaging in the cardiac catheterization laboratory

Worldwide experience in coronary catheterization and angiography for the detection and evaluation of lumen narrowing is extensive. Conventional coronary angiography analysis is complex since these arteries are of relatively small caliber and in constant movement, while being synchronized with the movement of the heart chambers and respiratory system. Moreover, atherosclerotic plaques in the coronary tree are themselves very intricate and frequently positioned in eccentric locations. The last decade has witnessed significant advances as novel data acquisition and processing techniques have been introduced. Researchers have developed novel processing systems that make it possible to construct 3D images in real-time during coronary intervention. The most common solutions are rotational imaging and reconstruction from multiple single-plane images. These techniques produce real-time 3D images of the coronary arteries in the catheterization laboratory. This article describes these state-of-the-art imaging methods and other specific novel applications in clinical practice, such as stent enhancement, guidance during transcatheter aortic valve implantation and advanced geometrical analysis with computational fluid dynamics.

3-Dimensional bifurcation angle analysis in patients with left main disease: a substudy of the SYNTAX trial (SYNergy Between Percutaneous Coronary Intervention with TAXus and Cardiac Surgery)

OBJECTIVES

We explore the bifurcation angle (BA) parameters of the left main coronary artery (LM), the effect of percutaneous coronary intervention (PCI) on this angulation, and the impact of BA on clinical outcome.

BACKGROUND

The BA is emerging as a predictor of outcome after PCI of bifurcation lesions. Three-dimensional (3D) quantitative coronary angiography (QCA) overcomes the shortcomings of 2-dimensional analysis and provides reliable data.

METHODS

This is a substudy of the SYNTAX (SYNergy Between Percutaneous Coronary Intervention With TAXus and Cardiac Surgery) trial. The cineangiograms of the 354 patients who underwent PCI of their LM stem were analyzed with 3D QCA software (CardiOp-B, Paieon Medical, Ltd., Rosh Ha'ayin, Israel). The proximal BA (between LM and left circumflex [LCX]) and the distal BA (between left anterior descending and LCX) were computed in end-diastole and end-systole, both before and after PCI. The cumulative major adverse cardiac and cardiovascular event (MACCE) rates throughout the 12-month period after randomization were stratified across pre-PCI distal BA values and compared accordingly.

RESULTS

Complete analysis was feasible in 266 (75.1%) patients. Proximal and distal BA had mean pre-PCI end-diastolic values of 105.9 +/- 21.7 degrees and 95.6 +/- 23.6 degrees , respectively, and were inversely correlated (r = -0.75, p < 0.001). During systolic motion of the heart there was an enlargement of the proximal angle and a reduction of the distal angle (DeltaBA -8.2 degrees and 8.5 degrees , respectively, p < 0.001 for both). The PCI resulted in a mean decrease in the distal BA (DeltaBA 4.5 degrees , p < 0.001). The MACCE rates did not differ across distal BA values; freedom from MACCE at 12 months was 82.8%, 85.4%, and 81.1% (p = 0.74) for diastolic values (first through third tertile).

CONCLUSIONS

Left main BA analysis with 3D QCA is feasible. Both proximal and distal angles are affected by cardiac motion; PCI modifies the distal angle. There is no clear difference in event rates across pre-PCI distal BA values.

Three-dimensional vessel analyses provide more accurate length estimations than the gold standard QCA

OBJECTIVES

The aim of this study was to compare lesion dimensions as determined by a three-dimensional quantitative coronary angiographic (QCA) system to that of a validated two-dimensional QCA system.

BACKGROUND

In an era of drug-eluting stents, device sizing has become an important clinical application of online QCA. The CardiOp-B system integrates two standard angiographic projections to provide a three-dimensional reconstruction of the arterial segment of interest.

METHODS

Phase 1 - 47 stenoses from consecutive coronary angiograms were assessed in two projections with both systems providing two data sets for the CMS-Medis system and a single data set for CardiOp-B. Phase 2--a perspex phantom with a known lesion length, was analyzed at increasing degrees of foreshortening with acceptance criteria set at 5% from the absolute value.

RESULTS

Phase 1 demonstrated an adequate correlation between the CardiOp-B and Medis systems when minimal luminal diameter was measured in the optimal view (1.32 +/- 0.47 mm vs 1.42 +/- 0.49 mm respectively; r = 0.82). A stronger correlation was noted when length was measured (25.27 +/- 10.76 mm and 21.32 +/- 8.08 mm, respectively; r = 0.95); however CardiOp-B provided a consistently longer length (P < 0.0001). On phantom length measurements the mean accuracy result for the CardiOp-B system was -1.3%. This compared favorably with the two-dimensional system where all measures performed at greater than 20 degrees of for shortening were beyond the 5% criteria from the known length.

CONCLUSIONS

Three-dimensional QCA provides accurate and precise vessel diameter assessments. Length assessments are consistently longer than two-dimensional measures and are significantly less affected by foreshortened projections.

A novel 3-d reconstruction system for the assessment of bifurcation lesions treated by the mini-crush technique

BACKGROUND

Conventional two-dimensional angiography lacks the ability to properly image the true bifurcation geometry, and its percutaneous coronary intervention-induced changes in the clinical setting.

METHODS AND RESULTS

A novel three-dimensional reconstruction system was investigated by retrospectively analyzing 39 lesions in 35 consecutive patients with coronary bifurcation disease treated with the mini-crush technique. At baseline, significant correlations were proved between two- and three-dimensional systems in terms of either reference vessel diameter (R(2)= 0.68 and 0.29 for main and side branches, respectively), minimum lumen diameter (R(2)= 0.73 and 0.36), stenosis diameter (R(2)= 0.69 and 0.29), and lesion length (R(2)= 0.48 and 0.58). These results were consistent with those observed after the procedure and at 8-month follow-up. Lesion length was significantly longer with the three-dimensional compared to the two-dimensional system for both main and side branches (P < 0.001, and P = 0.007, respectively).

CONCLUSIONS

The three-dimensional quantitative reconstruction system may provide accurate evaluation of the complex curvilinear structure of bifurcation lesions when using a double stent technique.

Three-dimensional coronary imaging for the ostium of the left anterior descending artery

Conventional coronary angiography is subject to a significant foreshortening of the proximal left anterior descending artery and overlapping of the left anterior descending artery and the circumflex artery that limits the accurate identification of the ostium of the left anterior descending artery. The aim of this study was to determine whether the three-dimensional (3D) reconstruction of traditional coronary angiography could optimize the projection angle to clearly show the ostium of the left anterior descending artery. The left main bifurcations of 18 consecutive patients were analyzed. A 3D image of the bifurcation was reconstructed from two conventional images and the optimal projection angle was chosen to clearly identify the ostium of the left anterior descending artery. The optimal angle was the right anterior oblique 18.8 +/- 20.9 degrees-caudal 26.9 +/- 32.3 degrees. The length from the left main trunk to the proximal left anterior descending artery on the optimal views was significantly longer than that on the routine views (25.0 +/- 6.1 vs. 22.4 +/- 5.3 mm, P = 0.011). The angles of the left main bifurcations were not substantially different between the optimal and the routine views. The optimal views selected using the 3D system provided clearer images of the ostium of the left anterior descending artery with less overlapping and foreshortening.

First direct in vivo comparison of two commercially available three-dimensional quantitative coronary angiography systems

AIM

The in vivo comparison of the accuracy of two 3-dimensional quantitative coronary angiography (QCA) systems.

METHODS

Precision-drilled plexiglass phantoms with five different luminal diameters (0.5-1.9 mm) were percutaneously inserted into the coronary arteries of four Yorkshire pigs. Twenty-one angiographic images of these stenotic phantoms were acquired for in vivo validation testing. Quantitative assessments of the minimum, maximum, and mean luminal diameters together with the minimum luminal area were determined using two 3D QCA systems, the CardiOp-B and CAAS 5.

RESULTS

The CardiOp-B system significantly underestimated the minimum luminal diameter MLD whilst both systems significantly overestimated the maximum luminal diameter at the minimal luminal area (MLA) over the phantom's true value. The CAAS 5 system had a greater degree of accuracy/mm (mean difference = 0.01 vs. 0.03) and precision/mm (SD = 0.09 vs. 0.23) than the CardiOp-B in assessing the minimal LD. An increased precision/mm (SD = 0.01 vs. 0.29) and accuracy/mm (mean difference = 0.03 vs. 0.11) in the mean LD was observed with the CAAS 5. In comparing the MLA/mm(2) the CAAS 5 was more precise/mm(2) (SD = 0.14 vs. 0.55) and accurate/mm(2) (mean difference = 0.12 vs. 0.02) to the true phantom MLA compared to the CardiOp-B system.

CONCLUSIONS

In a 21 phantom study, the CAAS 5 3D QCA system had a greater degree of accuracy and precision in both the luminal and area measurements than the CardiOp-B 3D QCA system.

Utility of three-dimensional reconstruction of coronary angiography to guide percutaneous coronary intervention

OBJECTIVE

The goal of this study was to determine whether three-dimensional (3D) reconstruction of traditional coronary angiography could optimize the choice of drug-eluting stent (DES) length and number during percutaneous coronary intervention (PCI).

BACKGROUND

Coronary angiography is subject to significant foreshortening artifact that limits the ability of the operator to accurately determine lesion length.

METHODS

The angiographic images of the target vessels of consecutive PCI procedures were postprocessed using a 3D reconstruction algorithm. The appropriate length and optimal number of DES to span each target lesion were calculated and compared with the number and length of DES actually chosen by the operator.

RESULTS

A total of 42 target vessels were analyzed, and 3D reconstruction was successful in 38/42 (90.5%) of cases. The results of 3D analysis would have changed operator decision making in six cases (16%): in four cases, the stent chosen by the operator was too short requiring an additional DES; in two cases, the chosen DES was too long and exchanged for a shorter one. In each of these six cases, 3D analysis would have determined the correct stent length prior to stent selection. The optimal stent number derived by 3D reconstruction was significantly less than the actual number of stents per lesion used by the operator (1.31 +/- 0.47 versus 1.54 +/- 0.68, P = 0.01), and the optimal stent length trended less than the actual stented length (27.5 +/- 12.8 mm versus 28.7 +/- 14.7 mm, P = 0.23).

CONCLUSIONS

3D reconstruction algorithm of standard coronary angiography is a promising technique to improve DES utilization during PCI.