Study Design. Prospective longitudinal study.
Objective. To verify the feasibility of performing in vivo quantitative magnetic resonance imaging evaluation of moderate traumatic spinal cord injury (SCI) in rats using a clinical 3T scanner.
Summary of Background Data. Animal models of human diseases are essential for translational medicine. Potential treatments of SCI are evaluated in 2 ways: anatomical and functional. Advanced magnetic resonance sequences allow a noninvasive assessment of the spinal cord depicting both. This study describes and validates a very reproducible, feasible, affordable, and reliable method, designed to be applied in commercial 3T equipment, using a novel stereotactic device for spinal cord, leading to a readily available assessment of the progression of damage generated after traumatic SCI in rats.
Methods. Four Long-Evans female rats were injured with a New York University weight-drop device to produce the SCI by contusion at thoracic level 10. All animals were placed in a fixation system, using a commercial wrist antenna to obtain magnetic resonance imaging data of the relaxometry time, apparent diffusion coefficient, and fractional anisotropy. Three sets of data obtained before SCI and 1 and 4 weeks after injury were compared.
Results. The data showed a progressive decline in fractional anisotropy measurements after SCI comparing baseline versus the 1-week period (P < 0.001) and baseline versus the 4-week period (P < 0.019), with a significant progressive increase in apparent diffusion coefficient values and T2 after SCI only in the baseline versus the 4-week period (P < 0.045 and P < 0.024, respectively).
Conclusion. Our results helped us to validate a novel method to acquire highly reproducible and reliable quantitative biomarkers of traumatic SCI in vivo by using a 3T clinical MR scanner coupled with a novel stereotactic device for rats.
Level of Evidence: N/A
Evidence was obtained about the feasibility to perform quantitative evaluation of spinal cord injury in a rat model using a clinical 3T MR scanner, a wrist coil, and a homemade fixation system. Fractional anisotropy, apparent diffusion coefficient, and T2 relaxometry are imaging biomarkers able to reflect differences before and after spinal cord injury.
*Departamento de Ingeniería Eléctrica, Universidad Autónoma Metropolitana, México;
†Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía, México;
‡Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana, México;
§Departamento de Física, Universidad Autónoma Metropolitana, México;
¶GE Healthcare, Mexico;
‖Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México; and
**Magnetic Resonance Unit, Medica Sur Clinic & Foundation, Mexico City, Mexico.
Address correspondence and reprint requests to Ernesto Roldan-Valadez, MD, MSc, Coordination of Research and Innovation in MRI, Magnetic Resonance Unit, Medica Sur Clinic & Foundation., Puente de Piedra 150, Toriello Guerra, Tlalpan, CP 14050, Mexico City, Mexico; E-mail: firstname.lastname@example.org
Acknowledgment date: January 18, 2013. First revision date: April 11, 2013. Second revision date: May 30, 2013. Acceptance date: May 31, 2013.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work.
No relevant financial activities outside the submitted work.