Acto3D: an open-source user-friendly volume rendering software for high-resolution 3D fluorescence imaging in biology.

Advances in fluorescence microscopy and tissue-clearing have revolutionised 3D imaging of fluorescently labelled tissues, organs and embryos. However, the complexity and high cost of existing software and computing solutions limit their widespread adoption, especially by researchers with limited resources. Here, we present Acto3D, an open-source software, designed to streamline the generation and analysis of high-resolution 3D images of targets labelled with multiple fluorescent probes. Acto3D provides an intuitive interface for easy 3D data import and visualisation. Although Acto3D offers straightforward 3D viewing, it performs all computations explicitly, giving users detailed control over the displayed images. Leveraging an integrated graphics processing unit, Acto3D deploys all pixel data to system memory, reducing visualisation latency. This approach facilitates accurate image reconstruction and efficient data processing in 3D, eliminating the need for expensive high-performance computers and dedicated graphics processing units. We have also introduced a method for efficiently extracting lumen structures in 3D. We have validated Acto3D by imaging mouse embryonic structures and by performing 3D reconstruction of pharyngeal arch arteries while preserving fluorescence information. Acto3D is a cost-effective and efficient platform for biological research.

Pulmonary arteriovenous malformations in a patient with single ventricle and polysplenia syndrome.

A 5-month-old girl with single ventricle, interrupted inferior vena cava and polysplenia syndrome palliated with bilateral Blalock-Taussig shunts developed severe cyanosis despite apparently increased pulmonary blood flow. Angiography revealed diffuse pulmonary arteriolar capillary dilatation and early pulmonary venous filling, suggesting the presence of pulmonary arteriovenous malformations. Abdominal angiography at 6 months demonstrated a large extrahepatic portosystemic shunt, which was percutaneously closed with a vascular plug. Kawashima operation was performed 2 weeks after portosystemic shunt closure. Although cyanosis improved temporarily, the patient suffered from deteriorating cyanosis at 9 months of age and underwent Fontan completion. Thereafter, her oxygen saturation gradually improved to 95% over the course of 3 weeks. Both the congenital extrahepatic portosystemic shunt and Kawashima operation contributed to the development of pulmonary arteriovenous malformations.

Impact of Pulmonary Valve Regurgitation on Pressure Difference of Pulmonary Valve Stenosis in Patients with Tetralogy of Fallot After Repair.

Pressure difference (PD) is an important parameter in evaluating the degree of stenotic lesion. However, PD is influenced by the blood flow volume passing through the stenosis. In patients with tetralogy of Fallot (TOF), pulmonary valve regurgitation (PR) and pulmonary valve stenosis (vPS) are common post-operative complications. The aim of this study was to evaluate the influence of PR on the PD. First, we examined the relationship between the peak-to-peak PD and the valve orifice area in 7 patients with vPS from their cardiac catheterization data. Second, an estimated PD, i.e., PD assuming no PR, was calculated in 8 patients with TOF with vPS and PR from their valve orifice area using the relational equation in patients with vPS. Moreover, an excess of PD, equating to the difference between the measured and estimated PD, was calculated. Finally, the relationship between the regurgitant fraction (RF) and the excess PD was analyzed. There was a strong relationship between the reciprocal of the valve orifice area and the PD in patients with vPS (r = 0.904, p = 0.0053). The excess PD showed a significant correlation with the RF in patients with TOF (r = 0.889, p = 0.0032). PR of over 25% in RF augmented the PD depending on the regurgitant volume. Severity of vPS could be overestimated in post-operative patients with TOF who had significant PR when their RF was above 25%.