Morphometric Magnetic Resonance Imaging Evaluation of Cervical Spinal Canal and Cord in Normal Small-Breed Dogs

Morphometric Evaluation of the Thoracic and Lumbar Vertebral Canal and Spinal Cord Using Computed Tomography in Healthy Korean Shorthair Cats

This study aimed to evaluate the spinal morphometry of the thoracic and lumbar regions in normal Korean Shorthair cats using computed tomography (CT) and to investigate the relationship with variables such as sex, age and body weight. Fifteen clinically healthy Korean Shorthair cats (eight males, seven females) from Seoul National University Veterinary Medical Teaching Hospital were included in this retrospective study. Measurements of the height, width and area of the vertebral canal and spinal cord on CT images were taken at the cranial, middle and caudal points of the thoracic and lumbar vertebrae by three observers, and the ratios of the spinal cord area to the vertebral canal area were calculated. The significance of the differences in measurements between sexes and correlations with age and body weight were analysed. The mean age of the cats was 7 years (range: 2-12 years), with a mean weight of 5.27 kg (range: 2.6-8.3 kg). The height, width and area of the vertebral canal and spinal cord were significantly greater in males than in females (p < 0.05). The ratios of the spinal cord area to the vertebral canal area showed no significant difference between sexes (p > 0.05), and no significant correlations were found between the ratios of the spinal cord area to the vertebral canal area and age or body weight. This study provides useful reference intervals for spinal morphometry in the thoracic and lumbar regions of healthy Korean Shorthair cats and investigate the relationship with variables such as sex, age and body weight. This anatomical information may assist in the diagnosis and prognosis of thoracic, lumbar vertebral and spinal cord diseases using CT.

Craniocervical Morphometry in Pomeranians-Part II: Associations with Chiari-like Malformation and Syringomyelia

BACKGROUND

The aim of Part II of this two-part study is to describe and analyze the association of various aspects and measurements related to the morphometry of the skull and craniocervical region to CM/SM status of Pomeranians, by means of computed tomography (CT) and magnetic resonance imaging (MRI).

METHODS

Prospectively, Pomeranians were included that underwent both CT and MRI studies of the head and cervicothoracic vertebral column. For those cases where qualitative classifications differed between observers, the experienced observer re-evaluated the studies and decided on a final classification that was used for further analysis. For quantitative measurements, the means of the observers' measurements were used for analysis.

RESULTS

Among statistically significant differences in measurements, we found that dogs with SM had a significantly shorter clivus length based on both MRI (p = 0.01) and CT measurements (p = 0.01), and a significantly smaller caudal cranial fossa area based on both MRI (p = 0.02) and CT measurements (p = 0.02).

CONCLUSIONS

Significant morphometrical differences were identified between dogs with or without CM/SM. The findings in this study add to those already described in other breeds and provide further insight into factors that may play a role in the pathogenesis of CM/SM in Pomeranians.

Craniocervical Morphometry in Pomeranians-Part I: Intra-Observer, Interobserver, and Intermodality (CT vs. MRI) Agreement

BACKGROUND

Currently, there are no diagnostic imaging-based studies that have focused specifically on the craniocervical morphology of Pomeranian dogs in relation to Chiari-like malformation and syringomyelia (CM/SM). The aims of Part I of this two-part study are to assess the intra-observer, interobserver, and intermodality reliability and agreement for various aspects of the craniocervical morphology of Pomeranians with and without CM/SM.

METHODS

Prospectively, Pomeranians were included that underwent both CT and MRI studies of the head and cervicothoracic vertebral column. Two observers (experienced and novice) independently performed CM and SM classifications, qualitative assessments, and quantitative measurements. The experienced observer performed these assessments twice. A third observer (experienced) performed CM and SM normal or abnormal classifications.

RESULTS

Ninety-nine (99) dogs were included. Interobserver reliability was influenced by observer experience level. For the experienced versus novice observers, substantial interobserver agreement was found for classification of SM as normal or abnormal (Cohen's kappa = 0.63), while interobserver agreement was fair for classification of SM as normal or abnormal (Cohen's kappa = 0.31). Interobserver, intra-observer, and intermodality reliability were variable for different measurements and assessments, and best overall for the CT-based measurements.

CONCLUSIONS

Interobserver reliability and agreement results should be taken into account in the evaluation of results of future studies as well as the evaluation of imaging studies of Pomeranians presented clinically.

Morphometric Evaluation of Thoracolumbar Spinal Canal and Cord by Magnetic Resonance Imaging in Normal Small-Breed Dogs

Thoracolumbar intervertebral disc disease (IVDD) is the most common cause of spinal injury in dogs. MRI has been considered the gold standard for neurologic diagnosis, but studies focusing on the thoracolumbar spinal canal and spinal cord using MRI in small-breed dogs are limited. Therefore, this study aimed to establish an MRI reference range for the spinal cord and canal measurements (height, width, cord-to-canal ratio of height, width, cross-sectional area (CSA)) of each intervertebral disc level from T11 to L5 (total of seven levels) on transverse T2-weighted images in normal small-breed dogs. We hypothesized that the spinal cord and spinal canal measurements might vary according to the body weight and age. The width and height of the spinal cord and canal increased as the body weight increased at all levels (p < 0.05). The cord-to-canal ratio of the width showed a negative correlation to the body weight at all levels. The cord-to-canal ratio of the height did not show any correlation to the body weight at all levels. All measurements (height, width, cord-to-canal ratio of height, width, CSA) did not show any statistical correlation between the groups subdivided by age. These measurements could serve as a morphometric baseline for thoracolumbar spinal diseases and clinical research in small-breed dogs.

Evolution of Spinal Cord Transection of Rhesus Monkey Implanted with Polymer Synthesized by Plasma Evaluated by Diffusion Tensor Imaging

In spinal cord injury (SCI) there is damage to the nervous tissue, due to the initial damage and pathophysiological processes that are triggered subsequently. There is no effective therapeutic strategy for motor functional recovery derived from the injury. Several studies have demonstrated neurons growth in cell cultures on polymers synthesized by plasma derived from pyrrole, and the increased recovery of motor function in rats by implanting the polymer in acute states of the SCI in contusion and transection models. In the process of transferring these advances towards humans it is recommended to test in mayor species, such as nonhuman primates, prioritizing the use of non-invasive techniques to evaluate the injury progression with the applied treatments. This work shows the ability of diffusion tensor imaging (DTI) to evaluate the evolution of the SCI in nonhuman primates through the fraction of anisotropy (FA) analysis and the diffusion tensor tractography (DTT) calculus. The injury progression was analysed up to 3 months after the injury day by FA and DTT. The FA recovery and the DTT re-stabilization were observed in the experimental implanted subject with the polymer, in contrast with the non-implanted subject. The parameters derived from DTI are concordant with the histology and the motor functional behaviour.