Linear relationship found by magnetic resonance imaging between cerebrospinal fluid volume and body weight in dogs

Despite numerous studies on cerebrospinal fluid (CSF) and its importance during hydrocephalus or myelography, no reliable values exist about its overall volume in dogs. In this study, our aim was to measure the intracranial (IC) volume of CSF in dogs and assess its possible relationship with body size and the symmetry of the lateral ventricles. We ran a 3D magnetic resonance imaging (MRI) sequence on the central nervous system of 12 healthy, male mongrel dogs between 3–5 years of age and 7.5–35.0 kg body weight. A validated semiautomatic segmentation protocol was implemented to segment the CSF and measure its volume. Values for the volume of the ventricular compartment were between 0.97 and 2.94 ml, with 62.1 ± 11.7% in the lateral ventricles, 17.6 ± 4.9% in the third ventricle, 4.9 ± 1.6% in the aqueductus mesencephali and 15.5 ± 6.6% in the fourth ventricle. In 11 cases a significant asymmetry was found between the lateral ventricles. The results suggest that it may be normal for a dog to have one of the lateral ventricles 1.5 times larger than the other. The correlation between body weight and CSF volume was linear, indicating that the current dosage protocols for myelography, based on a hypothetical proportional relationship with body weight, may have to be revised

Application of the cross sectional diagnostic imaging methods (CT and MR) in anatomical 3D reconstructions Part 1. CT based modeling of the air containing parts

SUMMARY Background: Computed tomography (CT) became an important diagnostic imaging method in the veterinary practice in the past decades. Data gained with the scanning can be used for 3D displaying of organs or body regions as well. The viewer softwares provide more and more options for reconstruction of the target area.Objectives: The authors present their own results about the 3D reconstruction of the avian air sacs (turkey) and the paranasal sinuses of the horse head based on data gained with a Siemens Definition Flash Dual CT.Materials and Methods: A Siemens Definition Flash Dual Source 2 x 128 slices CT was used to scan 5 male turkey toms at the age of 20 weeks. A head of a 7 years old stallion cadaver was examined with the same scanner. The resulting DICOM data were reconstructed with the 3DSlicer software using manual and semi-auto-matic segmentations, focusing on the air sac system and the paranasal sinuses. Results and discussion: Based on the Hounsfield Unit (HU) of the air the authors created 3D models of the avian air sac system, the nasal cavity, the guttural pouch and paranasal sinuses of the horse. The slice thickness of the scans (2 mm for the turkeys and 0.6 mm for the horse head) were sufficient to generate anatomically correct and detailed shape of the above-mentioned parts of the airways. The methods used for these reconstructions can be used for other organs, organ systems or body regions as well but require high contrast difference between the different anatomical structures or tissues. If such contrast deviations are not present naturally, contrast enhancement for the scanning procedures (in vivo contrast media administration, post mortem contrast enhancement methods) could be used. The resulted 3D anatomical models can be used in education, surgical planning and in animal breeding. In the second part of this article series the authors will present the bony and soft tissue model of the equine stifle joint, based on CT and MR image fusion

Application of the cross sectional diagnostic imaging methods (CT and MR) in anatomical 3D reconstructions Part 2. Soft tissue and bone reconstruction. CT and MR fusion modeling of the equine stifle joint

SUMMARY Background: Computed tomography (CT) and magnetic resonance imaging (MR) became important diagnostic tools in the veterinary practice in the past decades. Data gained with those scanning methods can be used for 3D displaying of different organs, organ systems and body regions as well. There are numerous reconstructional soft-wares to create high detailed and precise 3D anatomical models of the target area, based on those datasets.objectives: The authors present their own results about the 3D reconstruction of the bony and soft tissues of the equine stifle joint, based on image fusion of CT and MR data.Material and Methods: A Siemens Definition Flash Dual Source 2x128 slices CT and a Simens Avanto 1.5T MR scanner was used to scan the stifle joint of an 8 years old mare horse. The resulting DICOM data were reconstructed with the 3DSlicer software using manual, semi-automatic and automatic segmentations. First the bony structures of the stifle were reconstructed from the CT dataset. The soft tissues of the stifle joint: cavities of the femoropatellar, medial femorotibial, lateral femorotibial, subextensory recess of the lateral femorotibial joints, the menisci, and the different ligaments were reconstructed after the image fusion of the MR data with the 3D bony model from created from the CT.Results and discussion: In the second part of this article series the authors give a short review about the technical details of the MR imaging method, the CT and MR anatomy of the equine stifle and the procedure how they created the 3D model. The authors created 3D models from the bones of the equine stifle from the CT data set. In the second step they made an image fusion with the MR data of the same stifle joint. The methods used for these reconstructions can be used for other organs, organ systems or body regions as well but require high contrast difference between the different anatomical structures or tissues. If such contrast deviations are not present naturally, contrast enhancement for the scanning procedures (in vivo contrast media administration, post mortem contrast enhancement methods) could be used