[A Novel Virtual-reality Imaging System in Cardiovascular Surgery:a Potentially Promising Technology for Surgeons].

Adequate preoperative planning may facilitate successful procedures in cardiovascular surgery. We have developed a system named the Vesalius 3D suite, combining three-dimensional (3D) image-processing software with an optic-tracking spatial navigation, allowing quick, accessible 3D image interpretation for virtual reality (VR) exploration and measurement from one or more of a range of imaging modalities. We present a novel method of virtual imaging analysis for preoperative planning and simulation in cardiovascular surgery using this 3D-VR system. Based on unimodal or multimodal medical imaging data, digital imaging and communication in medicine (DICOM) data sets can be reconstructed for 3D visualization. Virtually reconstructed images can be viewed on flat-screen or stereoscopic display, revealing each patient's specific anatomy and the internal structures in exquisite detail. Highly accessible 3D interpretation promptly permits precise measurements of repair-relevant anatomical parameters including geometrically complex shapes. This technology may promote understanding of form and function in the cardiovascular system, and facilitate operative procedures in more challenging cases, and it seems especially valuable for any surgeon to gain experience in practicing for rarely-performed procedures or uncommon patient-specific preoperative surgical rehearsal.

Ex-vivo aortic root and coronary artery cast measurement to validate the accuracy of virtual imaging.

BACKGROUND AND AIM OF THE STUDY: To investigate the accuracy of two methods of measuring features in cardiac anatomy, using an objective standard cast model. METHODS: We made a silicone cast using a swine heart. Computerized tomography data of the solidified cast were processed through virtual reality (VR) software and through two-dimensional multiplanar-reconstruction (2D-MPR), and all measurements were compared against physical measurements of the cast. RESULTS: The cast perfectly demonstrated the fine detail of the aortic valve and the proximal parts of coronary arteries. Anatomical features were measured by 3D-VR, 2D-MPR, and directly on the cast. Measurement differences between 2D-MPR and the cast were on average at least 3.6 times larger than those between 3D-VR and the cast. CONCLUSIONS: Based on the observed accuracy, 3D-VR measurements seem considerably more accurate than the current standard 2D-MPR, and 3D-VR may be considered as the next gold standard for 3D measurement of cardiac anatomy in vivo.

Validation of Virtual Imaging of a Dynamic, Functioning Aortic Valve Using an Ex Vivo Porcine Heart.

PURPOSE: To investigate a virtual reality imaging system in terms of visualization accuracy and appropriate orientation when displaying cardiac anatomy, we used an ex vivo model enabling direct comparison between reconstructed 3-dimensional visualization of intracardiac structures and real-time visual images. DESCRIPTION: We established a systole-diastole platform using a swine heart activated by an external mechanical pump and reservoir, allowing simultaneous acquisition of endoscopic visual and computed tomography images of the aortic valve. Virtual images were processed from computed tomography data using 3-dimensional software (the Vesalius 3D suite; PS Medtech, Amsterdam, Netherlands) and compared with visual images seen through a fiberoptic scope. EVALUATION: An endoscope gave a fine view of the aortic valve, whereas the virtual images elucidated the valve structures. Superimposition of the images from the 2 different modalities showed the virtual reality images precisely matching the visual images in both systole and diastole, confirming the validity of this virtual reality application. CONCLUSION: In view of this demonstrated fidelity of virtual imaging, this technology may be of sufficiently high quality to be considered a gold standard for cardiac anatomy.

Mesoscopic Architectures Made of Electrically Charged Binary Colloidal Nanosheets in Aqueous System.

Inorganic layered materials can be converted to colloidal liquid crystals through exfoliation into inorganic nanosheets, and binary nanosheet colloids exhibit rich phase behavior characterized by multiphase coexistence. In particular, niobate-clay binary nanosheet colloids are characterized by phase separation at a mesoscopic (∼several tens of micrometers) scale whereas they are apparently homogeneous at a macroscopic scale. Although the mesoscopic structure of the niobate-clay binary colloid is advantageous to realize unusual photochemical functions, the structure itself has not been clearly demonstrated in real space. The present study investigated the structure of niobate-clay binary nanosheet colloids in detail. Four clay nanosheets (hectorite, saponite, fluorohectorite, and tetrasilisic mica) with different lateral sizes were compared. Small-angle X-ray scattering (SAXS) indicated lamellar ordering of niobate nanosheets in the binary colloid. The basal spacing of the lamellar phase was reduced by increasing the concentration of clay nanosheets, indicating the compression of the liquid crystalline niobate phase by the isotropic clay phase. Scattering and fluorescence microscope observations using confocal laser scanning microscopy (CLSM) demonstrated the phase separation of niobate and clay nanosheets in real space. Niobate nanosheets assembled into domains of several tens of micrometers whereas clay nanosheets were located in voids between the niobate domains. The results clearly confirmed the spatial separation of two nanosheets and the phase separation at a mesoscopic scale. Distribution of clay nanosheets is dependent on the employed clay nanosheets; the nanosheets with large lateral length are more localized or assembled. This is in harmony with larger basal spacings of niobate lamellar phase for large clay particles. Although three-dimensional compression of the niobate phase by the coexisting clay phase was observed at low clay concentrations, the basal spacing of niobate phase was almost constant irrespective of niobate concentrations at high clay concentrations, which was ascribed to competition of compression by clay phase and restoring of the niobate phase.

[Minimally Invasive Coronary Artery Bypass Grafting Using Bilateral In Situ Internal Thoracic Arteries].

A 73-year-old male with diabetes mellitius was referred to our hospital for coronary artery bypass grafting (CABG). Preoperative coronary angiography revealed three-vessel coronary disease. Minimally invasive coronary artery grafting (MICS CABG) via left thoracotomy was selected to decrease surgical site infection due to severe diabetes. In situ bilateral internal thoracic arteries (BITA) were harvested using a long type Harmonic scalpel. In situ right internal thorac artery( RITA)-left anterior descending artery (LAD), in situ left internal thorac artery( LITA)-high lateral branch (HL), and aorta-saphenous vein graft (SVG)-#4 posterior descending artery were performed. BITA, the ascending aorta for proximal anastomosis, and all coronary targets were directly accessed with off-pump technique. There were no major postoperative complications. Postoperative 3D-computed tomography angiography (CTA) revealed all grafts were patent. We believe that use of BITA in MICS CABG is feasible, and can provide satisfactory quality. Further research however, will be needed.

[New Intracoronary Shunt Cannula in Off-pump Coronary Artery Bypass Grafting].

In off-pump coronary artery bypass grafting(OPCAB), a bloodless operative field has great influence on the quality of anastomosis. In addition, maintenance of distal coronary flow during anastomosis stabilizes hemodynamics. We introduced a new intracoronary shunt cannula, Mini Shunt Pro (MSP). MSP adopts the step-tip, which allows easy insertion and reduces the risk of intimal injury. The distal and proximal sides of the tips of MSP are 0.25 mm different in diameter, which improves its fitness to the coronary artery and enhances a bloodless operative field. This new shunt cannula is considered to be safe and useful for high-quality anastomosis in OPCAB.

[Rupture of Saccular Brachiocephalic Artery Aneurysm after One Year and Seven Months from Coil Embolization;Report of a Case].

A 52-years-old man, who had undergone coil embolization of saccular aneurysm of the brachiocephalic artery, presented with right back discomfort. Diagnosis by computed tomography was difficult because of an artifact from the coils. Angiography, on the other hand, revealed a rupture of the aneurysm, and emergency surgery was performed. A Y-shaped graft was anastomosed to the ascending aorta under partial clamp. Then, one of its branches was anastomosed to the common carotid artery also under partial clamp in an end-to-side fashion. The cerebral blood flow monitored by a regional oximetry system (INVOS) remained stable. The other branch was anastomosed to the subclavian artery in end-to end fashion. No postoperative neurologic complications occurred. Angiography was useful in diagnosis of brachiocephalic artery aneurysm rupture after coil embolization. INVOS was also useful for monitoring the cerebral blood flow during surgery.

[Mitral Valve Plasty in a Patient with Situs Inversus Totalis; Usefulness of Retrograde Cardioprotective Beating Test].

We report the usefulness of retrograde cardioprotective(RC)-beating test as a method to evaluate mitral valve plasty (MVP). MVP has been established as an effective procedure for mitral regurgitation, but nevertheless, a problem remains as to how to reduce postoperative residual regurgitation. In order to solve this problem, it is crucial to image the 3 dimensional structures of the mitral valve and its systolic condition. However, it is quite difficult especially in cases of situs inversus totalis (SIT). RC-beating test gives a clear view of the mitral valve and precisely evaluates the performance of MVP, which is particulary helpful in SIT patients. It also shows where to revise in cases of residual regurgitation.