OBJECTIVE To determine the optimal protocol for acquisition of CT images of the dentition in alpacas.
ANIMALS 3 healthy adult male alpacas.
PROCEDURES Each alpaca was anesthetized with an IM injection of a combination of ketamine, xylazine, and butorphanol and positioned in sternal recumbency on the CT couch with its legs folded in a natural cush position and its head positioned within the isocenter of the gantry of a 64-slice CT scanner. Images were acquired by means of 6 protocols (sequential and helical modes at slice thicknesses of 1.25, 2.5, and 5 mm). Five images (2 molar, 2 premolar, and mandibular incisor teeth) were selected from each protocol for evaluation by 3 veterinary radiologists. For each image, tooth root visibility and sharpness and image noise artifact were subjectively evaluated on a 3-point scoring system.
RESULTS Slice thickness significantly affected tooth root visibility and tooth root sharpness but did not affect image noise artifact. Acquisition mode significantly affected tooth root visibility and tooth root sharpness as well as image noise artifact. Tooth root visibility and sharpness did not differ significantly between the helical and sequential images when the slice thickness was 1.25 mm. Image noise artifact was greater for helical images than sequential images but did not differ by slice thickness within either acquisition mode.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that for a 64-slice CT scanner, the optimal protocol for the acquisition of CT images of the dentition in alpacas was a sequential scan with a slice thickness of 1.25 mm.
OBJECTIVE To compare time to achieve vascular access (TTVA) between an ultrasound-guided technique (UST) and landmark-based technique (LMT) for central venous catheter (CVC) placement in healthy anesthetized dogs.
ANIMALS 39 purpose-bred hounds.
PROCEDURES Anesthetized dogs that were hemodynamically stable following completion of a terminal surgical exercise were enrolled in the study during 2 phases, with a 45-day intermission between phases. For each dog, a UST and LMT were used for CVC placement via each external jugular vein by 2 operators (criticalist and resident). The TTVA and number of venipuncture attempts and catheter redirections were recorded for each catheterization. Placement of the CVC was confirmed by contrast fluoroscopy. After euthanasia, a gross dissection was performed during which a hematoma score was assigned to the catheter insertion site. For each phase, nonlinear least squares estimation was used for learning curve analysis of the UST.
RESULTS Median TTVA, number of venipuncture attempts and catheter redirections, and hematoma score did not differ significantly between the 2 operators for either technique. Median TTVA for the UST (45 seconds) was significantly longer than that for the LMT (7 seconds). Learning curve analysis indicated that 8 and 7 UST catheterizations were required to achieve performance stability in phases 1 and 2, respectively.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the UST was comparable to the LMT for CVC placement in healthy dogs. The extra time required to perform the UST was not clinically relevant. Additional studies evaluating the UST for CVC placement in clinically ill dogs are warranted.