Intelligent Algorithms-Based CT Image Segmentation in Patients with Cardiovascular Diseases and Realization of Visualization Algorithms

The study focused on the intelligent algorithms-based segmentation of computed tomography (CT) images of patients with cardiovascular diseases (CVD) and the realization of visualization algorithms. The first step was to design a method for precise segmentation under the cylinder model based on the coronary body data of the coarse segmentation, and then the principles of different visualization algorithms were discussed. The results showed that the precise segmentation method can effectively eliminate most of the branches and calcified lesions; curved planar reformation (CPR) and straightened CPR can display the entire blood vessel on one image; and spherical CPR can display the complete coronary artery tree on an image, so that a problem with a certain blood vessel can be quickly found. In conclusion, the precise segmentation of CT images of CVD and visualization algorithm based on the cylinder model have clinical significance in the diagnosis of CVD.

The Use of Closure Devices for Aortic Stent-Graft Insertion: Outcomes Following a Paradigm Shift to Percutaneous Access in a Tertiary Vascular Center

Background: This retrospective case series aims to evaluate the efficacy of the Perclose ProGlide system for postoperative hemostasis following aortic stent-graft insertion. Material and Methods: A prospectively maintained database of patients with a minimum follow-up of 12 months following percutaneous aortic procedures was interrogated. Preprocedural computed tomography (CT) scans were reviewed to assess existing stenosis in the common femoral artery (CFA). Arteries with an estimated stenosis of greater than 25% on visual inspection underwent quantification using multiplanar and curved planar reformation. The preoperative and 1-year follow-up CTs of these patients were assessed for change in stenosis. Analysis was performed by 2 independent reviewers, with senior authors reviewing any discrepancies. Results: One hundred forty-two endovascular aortic aneurysm repairs (EVARs) were performed. The ProGlide system was used in 235 arteries, yielding a high success rate in obtaining postprocedural hemostasis (94%). There were 13 postprocedural access-related complications, including 5 patients requiring surgical closure due to inadequate seal. Two patients required thrombectomy due to distal embolization. One patient required CFA endarterectomy at 6 months for the treatment of preexisting short distance claudication. Vessel analysis was performed in 31 arteries. Mean preoperative stenosis was 32% (range: 20%-57%). Mean postoperative stenosis was 32% (21%-57%). No significant change in degree of stenosis was detected (defined as a 5% change). Conclusions: The ProGlide system yielded a high success rate in obtaining postoperative hemostasis with low rate of conversion to surgical closure and low complication rates. There was no evidence of worsening vessel stenosis in arteries with preprocedural stenotic disease. Level of Evidence: Level 4, Case Series.

Automated Curved and Multiplanar Reformation for Screening of the Proximal Coronary Arteries in MR Angiography

Congenital anomalies of the coronary ostia can lead to sudden death. A screening solution would be useful to prevent adverse outcomes for the affected individuals. To be considered for integration into clinical routine, such a procedure must meet strict constraints in terms of invasiveness, time and user interaction. Imaging must be fast and seamlessly integrable into the clinical process. Non-contrast enhanced coronary magnetic resonance angiography (MRA) is well suited for this. Furthermore, planar reformations proved effective to reduce the acquired volumetric datasets to 2D images. These usually require time consuming user interaction, though. To fulfill the aforementioned challenges, we present a fully automated solution for imaging and reformatting of the proximal coronary arteries which enables rapid screening of these. The proposed pipeline consists of: (I) highly accelerated single breath-hold MRA data acquisition, (II) coronary ostia detection and vessel centerline extraction, and (III) curved planar reformation of the proximal coronary arteries, as well as multiplanar reformation of the coronary ostia. The procedure proved robust and effective in ten volunteer data sets. Imaging of the proximal coronary arteries took 24 ± 5 s and was successful within one breath-hold for all patients. The extracted centerlines achieve an overlap of 0.76 ± 0.18 compared to the reference standard and the average distance of the centerline points from the spherical surface for reformation was 1.1 ± 0.51 mm. The promising results encourage further experiments on patient data, particularly in coronary ostia anomaly screening.

Evaluating Visualisations and Automatic Warning Cues for Visual Search in Vascular Images

Visual search is a task that is performed in various application domains. The authors examine it in the domain of radiological analysis of 3D vascular images. They compare several major visualisations used in this domain, and study the possible benefits of automatic warning systems that highlight the sections that may contain visual targets and hence require the user’s attention. With help of a literature study, the authors present some theory about what result can be expected given the accuracy of a particular visual cue. They present the results of two experiments, in which they find that the Curved Planar Reformation visualisation, which presents a cross-section based on knowledge about the position of the blood vessel, is significantly more efficient than regular 3D visualisations, and that automatic warning systems that produce false alarms could work if they do not miss targets.

Bending the Curve: Preoperative Determination of Bypass Graft Length and Trajectory With Curved Planar Reformatted Computed Tomography Angiography: Technical Note

ABSTRACT BACKGROUND AND IMPORTANCE: Cerebral revascularization continues to be an important technique for the treatment of cerebrovascular and vaso-occlusive diseases, and determination of appropriate graft sources and recipients is paramount to the success of the procedure. A tension-free anastomosis requires that harvested grafts be of an appropriate length to avoid complications. Volume-rendered contrast-enhanced computed tomography data sets may be useful in determining the desired length and path of the bypass graft and in the evaluation of appropriate recipient vessels. Curved planar reformation techniques may allow these properties to be determined in a novel, inexpensive, and efficient manner. CLINICAL PRESENTATION: A 63-year-old patient with a left hemispheric perfusion deficit and without an external carotid artery was in need of high-flow cerebral revascularization. A radial artery graft spanning from the vertebral artery to the middle cerebral artery was proposed. Preoperative determination of graft length necessary and most efficient subcutaneous placement was desired. A standard computed tomography angiogram of the head and neck was obtained and imported into a computer workstation with curved planar reformatting capabilities. CONCLUSION: Curved planar reformation technique can be used for preoperative planning of cerebral bypass procedures and is a novel, inexpensive, and efficient means of determining the desired length and path of the bypass graft and in the evaluation of appropriate recipient vessels.