Computed tomographic and angiographic assessment of spinal extradural arteriovenous fistulas in a dog.

A 6-month-old German shepherd dog was presented for progressive paraparesis. Multiple arteriovenous fistulae and hyperostosis of the thoracic vertebrae with secondary thoraco-lumbar spinal cord compression were diagnosed. Arteriovenous spinal fistula is a rare condition but should be considered as a differential diagnosis in young dogs with progressive paraparesis.

Évaluation par tomodensitométrie et angiographie de fistules artérioveineuses extradurales spinales chez un chien. Un chien Berger allemand âgé de 6 mois a été présenté pour une paraparésie progressive. De nombreuses fistules artérioveineuses et de l'hyperostose des vertèbres thoraciques avec une compression de la colonne vertébrale thoraco-lombaire secondaire ont été diagnostiquées. Les fistules spinales artérioveineuses sont une rare affection mais elles devraient être considérées comme un diagnostic différentiel chez les jeunes chiens atteints de paraparésie progressive.(Traduit par Isabelle Vallières).

Retention assessment of magnetic nanoparticles in rat arteries with micro-computed tomography.

Magnetic nanoparticles (MNPs) may serve as carriers for pharmacological agents to the target in a magnetic-force guiding system. It is essential to achieve effective retention of MNPs through the external magnet placement. However, it is difficult to estimate the retention efficiency of MNPs and validate the experimental strategies. Micro-CT was used to identify the spatial distribution of MNP retention and image analysis is then extended to evaluate the MNP delivery efficiency. Male Sprague Dawley rats were anesthetized to expose abdominal arteries with an NdFeB magnet of 4.9 kG placed by the left iliac artery. After a 20 min equilibrium period, arteries were ligated, removed and fixed in a paraformaldehyde solution. Experiments were performed with intravenous injection in our platform with two independent groups. MNPs were used in the first group, while chemical compounds of recombinant tissue plaminogen activator were attached to MNPs as rtPA (recombinant tissue plaminogen activator)-MNPs in the second group. Image analysis of micro-CT shows the average retention volume of MNPs and rtPA-MNPs in the left iliac arteries is 9.3 and 6.3 fold of that in the right. Large local aggregation of MNPs and rtPA-MNPs in the left iliac arteries is the consequence of external magnet placement, suggesting feasibility of magnetic targeting through the intravenous administration. We also determined that on average 0.57% and 0.064% of MNPs and rtPA-MNPs respectively were retained in the left iliac artery. It was estimated that the average rtPA concentration of 60.16 µg mL(-1) may be achieved with rtPA-MNPs. With the micro-CT imaging approach, we accomplished visualization of the aggregation of retained particles; reconstructed 3D distribution of relative retention; estimated the average particle number of local retention; determined efficiency of targeted delivery. In particular, our quantitative image assessment suggests that intravenous administration of rtPA-MNPs may retain local concentration of rtPA high enough to induce thrombolysis.

Three-dimensional multislice helical computed tomography techniques for canine extra-hepatic portosystemic shunt assessment.

The purpose of the present study was to investigate the feasibility and usefulness of three-dimensional (3D) multislice computed tomography (CT) angiography with maximum intensity projection (MIP) and volume rendering (VR) in six dogs with clinical and sonographic findings suggestive of portosystemic shunt. Furthermore, we aimed to estimate the diameter of the portal vein and shunt vessels. MIP and VR reconstructions were performed for each patient and the origin and insertion of all shunt vessels were detected. In addition, 3D reconstructions allowed excellent depiction of vascular morphology and topography. All diagnoses and vessel measurements were confirmed by surgery. 3D multidetector CT angiography is a promising, noninvasive, and accurate method of evaluating dogs with suspected portosystemic shunts.