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Feasibility of In Vivo Quantitative Magnetic Resonance Imaging With Diffusion Weighted Imaging, T2-Weighted Relaxometry, and Diffusion Tensor Imaging in a Clinical 3 Tesla Magnetic Resonance Scanner for the Acute Traumatic Spinal Cord Injury of Rats: Technical Note

Mondragon-Lozano, Rodrigo MSc*; Diaz-Ruiz, Araceli PhD; Ríos, Camilo PhD†,‡; Olayo Gonzalez, Roberto PhD§; Favila, Rafael MSc; Salgado-Ceballos, Hermelinda PhD; Roldan-Valadez, Ernesto MD, MSc**

doi: 10.1097/BRS.0b013e31829ef69c
Basic Science

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: ernest.roldan@usa.net

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.

© 2013 by Lippincott Williams & Wilkins