Real-time fusion of coronary CT angiography with x-ray fluoroscopy during chronic total occlusion PCI.

OBJECTIVES: The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with x-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. RESULTS: Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. CONCLUSIONS: This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. KEY POINTS: • Real-time semi-automated fusion of CTA/fluoroscopy is feasible during CTO PCI. • CTA fusion data can be toggled on/off as desired during CTO PCI • Real-time CT calcium and centreline overlay could benefit antegrade dissection/reentry-based CTO PCI.

Image-guided video assisted thoracoscopic surgery (iVATS) - phase I-II clinical trial.

PURPOSE: To facilitate localization and resection of small lung nodules, we developed a prospective clinical trial (ClinicalTrials.gov number NCT01847209) for a novel surgical approach which combines placement of fiducials using intra-operative C-arm computed tomography (CT) guidance with standard thoracoscopic resection technique using image-guided video-assisted thoracoscopic surgery (iVATS). METHODS: Pretrial training was performed in a porcine model using C-arm CT and needle guidance software. Methodology and workflow for iVATS was developed, and a multi-modality team was trained. A prospective phase I-II clinical trial was initiated with the goal of recruiting eligible patients with small peripheral pulmonary nodules. Intra-operative C-arm CT scan was utilized for guidance of percutaneous marking with two T-bars (Kimberly-Clark, Roswell, GA) followed by VATS resection of the tumor. RESULTS: Twenty-five patients were enrolled; 23 underwent iVATS, one withdrew, and one lesion resolved. Size of lesions were: 0.6-1.8 cm, mean = 1.3 ± 0.38 cm.. All 23 patients underwent complete resection of their lesions. CT imaging of the resected specimens confirmed the removal of the T-bars and the nodule. Average and total procedure radiation dose was in the acceptable low range (median = 1501 µGy*m(2), range 665-16,326). There were no deaths, and all patients were discharged from the hospital (median length of stay = 4 days, range 2-12). Three patients had postoperative complications: one prolonged air-leak, one pneumonia, and one ileus. CONCLUSIONS: A successful and safe step-wise process has been established for iVATS, combining intra-operative C-arm CT scanning and thoracoscopic surgery in a hybrid operating room.

Contrast-Enhanced C-arm Computed Tomography Imaging of Myocardial Infarction in the Interventional Suite.

OBJECTIVES: Cardiac C-arm computed tomography (CT) uses a standard C-arm fluoroscopy system rotating around the patient to provide CT-like images during interventional procedures without moving the patient to a conventional CT scanner. We hypothesized that C-arm CT can be used to visualize and quantify the size of perfusion defects and late enhancement resulting from a myocardial infarction (MI) using contrast-enhanced techniques similar to previous CT and magnetic resonance imaging studies. MATERIALS AND METHODS: A balloon occlusion followed by reperfusion in a coronary artery was used to study acute and subacute MI in 12 swine. Electrocardiographically gated C-arm CT images were acquired the day of infarct creation (n = 6) or 4 weeks after infarct creation (n = 6). The images were acquired immediately after contrast injection, then at 1 minute, and every 5 minutes up to 30 minutes with no additional contrast. The volume of the infarct as measured on C-arm CT was compared against pathology. RESULTS: The volume of acute MI, visualized as a combined region of hyperenhancement with a hypoenhanced core, correlated well with pathologic staining (concordance correlation, 0.89; P < 0.0001; mean [SD] difference, 0.67 [2.98]cm3). The volume of subacute MI, visualized as a region of hyperenhancement, correlated well with pathologic staining at imaging times 5 to 15 minutes after contrast injection (concordance correlation, 0.82; P < 0.001; mean difference, -0.64 [1.94]cm3). CONCLUSIONS: C-arm CT visualization of acute and subacute MI is possible in a porcine model, but improvement in the imaging technique is important before clinical use. Visualization of MI in the catheterization laboratory may be possible and could provide 3-dimensional images for guidance during interventional procedures.

Contrast-enhanced C-arm CT evaluation of radiofrequency ablation lesions in the left ventricle.

OBJECTIVES: The purpose of this study was to evaluate use of cardiac C-arm computed tomography (CT) in the assessment of the dimensions and temporal characteristics of radiofrequency ablation (RFA) lesions. This imaging modality uses a standard C-arm fluoroscopy system rotating around the patient, providing CT-like images during the RFA procedure. BACKGROUND: Both cardiac magnetic resonance (CMR) and CT can be used to assess myocardial necrotic tissue. Several studies have reported visualizing cardiac RFA lesions with CMR; however, obtaining CMR images during interventional procedures is not common practice. Direct visualization of RFA lesions using C-arm CT during the procedure may improve outcomes and circumvent complications associated with cardiac ablation procedures. METHODS: RFA lesions were created on the endocardial surface of the left ventricle of 9 swine using a 7-F RFA catheter. An electrocardiographically gated C-arm CT imaging protocol was used to acquire projection images during iodine contrast injection and after the injection every 5 min for up to 30 min, with no additional contrast. Reconstructed images were analyzed offline. The mean and SD of the signal intensity of the lesion and normal myocardium were measured in all images in each time series. Lesion dimensions and area were measured and compared in pathologic specimens and C-arm CT images. RESULTS: All ablation lesions (n = 29) were visualized and lesion dimensions, as measured on C-arm CT, correlated well with postmortem tissue measurements (linear dimensions: concordance correlation = 0.87; area: concordance correlation = 0.90. Lesions were visualized as a perfusion defect on first-pass C-arm CT images with a signal intensity of 95 HU lower than that of normal myocardium (95% confidence interval: -111 HU to -79 HU). Images acquired at 1 and 5 min exhibited an enhancing ring surrounding the perfusion defect in 24 lesions (83%). CONCLUSIONS: RFA lesion size, including transmurality, can be assessed using electrocardiographically gated cardiac C-arm CT in the interventional suite. Visualization of RFA lesions using cardiac C-arm CT may facilitate the assessment of adequate lesion delivery and provide valuable feedback during cardiac ablation procedures.

Comparative study of high-resolution microimaging with 30-MHz scanner for evaluating cardiac function in mice.

BACKGROUND: The accurate assessment of cardiac function in mice is challenging because of their small heart size and rapid heart rate. METHODS: We examined the usefulness of novel high-resolution echocardiography (HRE) with a 30-MHz transducer in evaluating cardiac function in 20 mice compared with conventional echocardiography (CE) with a 13-MHz transducer. The left ventricular (LV) regional wall motion (RWM), LV end-diastolic dimension, fractional shortening, anterior LV wall thickness, E/A, and myocardial performance index were assessed. RESULTS: RWM analysis was more feasible by HRE than by CE (P < .05). Interobserver agreement in RWM analysis and correlation in LV end-diastolic dimension, fractional shortening, anterior LV wall thickness, E/A, and myocardial performance index were all better with HRE than CE. CONCLUSIONS: HRE is superior to CE in assessing LV function in mice. HRE is potentially a useful method for accurate assessment of cardiac function in various mice models.