Applications of Rapid Cardiac Micro-CT

Mouse models are an important tool in cardiovascular disease research and a non-invasive imaging method is an advantageous way of monitoring disease progression. Cardiac micro-CT is rapid imaging technique capable of quantifying changes in cardiac structure and function in mice. The goal of this thesis was to demonstrate the utility of this technique in monitoring disease progression in a longitudinal study, as well as its capability for evaluating other methods of measuring cardiac function in mice. In a longitudinal study, a mouse model of myocardial infarction was scanned weekly for four weeks; left ventricular volume and ejection fraction were measured from the images. Cardiac micro-CT was capable of tracking small changes in cardiac structure and function, with the MI mice demonstrating a significant increase in volume and a significant decrease in ejection fraction. Both inter- and intra-variability was low, indicating the results were highly reproducible. Contrast agents are essential to evaluating the heart in micro-CT images. A new blood-pool agent was evaluated to determine its suitability for use in cardiac micro-CT studies. The agent produced excellent enhancement for the first 30 minutes post-injection, and had a unique characteristic of enhancing the myocardium, which may prove useful in studies evaluating wall motion. The effect of x-ray dose delivered during a longitudinal micro-CT study was also evaluated. C57BL/6 mice were scanned weekly for six weeks; the total entrance dose delivered over the study was 5.04 Gy. No significant changes to the heart or lungs were detectable on the micro-CT images at six weeks, and the histology performed on myocardial and pulmonary tissue showed no indication of early inflammation at a cellular level. Micro-CT can therefore be used in longitudinal studies without concern of adverse effects. Cardiac micro-CT was used to evaluate conductance catheters, and found that the catheter volumes were drastically underestimated compared to the micro-CT volumes. It was also determined that catheterization has the potential for causing cardiac enlargement; 40% of the mice demonstrated enlarged hearts following the catheterization procedure. Overall, cardiac-gated micro-CT is a rapid and reproducible imaging technique, and is proving to be valuable tool in cardiovascular disease research

Spinal cord compression is associated with brain plasticity in degenerative cervical myelopathy.

The impact of spinal cord compression severity on brain plasticity and prognostic determinates is not yet fully understood. We investigated the association between the severity of spinal cord compression in patients with degenerative cervical myelopathy, a progressive disease of the spine, and functional plasticity in the motor cortex and subcortical areas using functional magnetic resonance imaging. A 3.0 T MRI scanner was used to acquire functional images of the brain in 23 degenerative cervical myelopathy patients. Patients were instructed to perform a structured finger-tapping task to activate the motor cortex to assess the extent of cortical activation.

Does the Neurological Examination Correlate with Patient-Perceived Outcomes in Degenerative Cervical Myelopathy?

© 2019 Elsevier Inc. Background: In patients with neurological disorders, a divergence can exist between patients\u27 perceptions regarding the outcomes and the objective neurological findings. Degenerative cervical myelopathy (DCM), a prevalent condition characterized by progressive compression of the cervical spinal cord, can produce debilitating symptoms and profound neurological findings. The purpose of the present study was to determine whether the physician-derived neurological examination findings, as recorded by American Spine Injury Association (ASIA) summary score, correlated with the patient-derived outcome measures for DCM. Methods: A total of 78 patients underwent surgical management of DCM with completion of preoperative and 6-month follow-up assessments. Surgical management consisted of either anterior or posterior cervical decompression. All patients underwent a neurological evaluation, including an ASIA assessment before surgery and 6 months after surgery, and completed the modified Japanese Orthopaedic Association (mJOA), neck disability index (NDI), and Short-Form 36-item (SF-36) scales pre- and postoperatively to measure both disease-specific and general perceived outcomes. Results: The objective physician-derived neurological testing (ASIA) did not correlate with the patient-derived scales (mJOA, NDI, and SF-36) pre- or postoperatively. Patients reported significant improvements (P \u3c 0.001) at 6 months postoperatively in extremity functioning (mJOA), neck pain (NDI), overall physical health (SF-36), and objective strength and sensory functioning (ASIA). All patient-perceived outcome measures correlated with each other pre- and postoperatively (P \u3c 0.01). Conclusions: Objective scoring of postoperative neurological function did not correlate with patient-perceived outcomes before and after surgery for DCM. Traditional testing of motor and sensory function as part of the neurological assessment may not be sensitive enough to assess the scope of neurological changes experienced by patients with DCM