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Findings: Abnormally increased T2 signal is seen within the central portion of the distal spinal cord, including the conus medullaris.
Diagnosis: Spinal cord infarction.
Discussion: The spinal cord is supplied by one anterior spinal artery, two posterolateral spinal arteries, and the perimedullary plexus connecting them. The anterior spinal artery is formed superiorly from branches from both vertebral arteries. It is also fed by several radicular arteries in the cervical and thoracic regions. The main blood supply to the lower spinal cord, approximately T8 through the conus medullaris is derived from the arteria radicularis anterior magna or artery of Adamkiewicz.
Although venous infarction can occur, spinal cord infarction is usually due to occlusion of one of the feeding arteries of the cord. However, the presence of numerous radicular arteries, especially in the upper spinal cord, allows reversal of flow, thus infarction occurs less often than it might otherwise. The artery of Adamkiewicz supplies the majority of the blood flow to the lower spinal cord; therefore, its occlusion can result in infarction of the lower spinal cord, including the conus medullaris.
Typically, in spinal cord infarction hyperintensity is seen within the spinal cord on proton density or T2 weighted images. In the acute stage, enlargement of the spinal cord is sometimes appreciated on T1 weighted images due to the presence of edema. Several months after infarction, the spinal cord may become atrophic. In this case, abnormally increased T2 signal was appreciated extending from the T12 through L1 level; however, no apparent enlargement of the spinal cord was appreciated.
Causes of spinal cord infarction include aortic surgery, trauma, complication from aortography, polycythemia, disc herniation, hypertension, syphilis, and thrombophlebitis.
References:
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In: Clinical Magnetic Resonance Imaging. Eds. Edelman RR, Hesselink JR.
W. B. Saunders Co, Philadelphia; 1990:679-680.
Taveras JM. Spine and Spinal Canal. In: Neuroradiology, Eds. Taveras JM.
Williams and Wilkins, Baltimore; 1996:871-873.
Yuh WTC, Marsh EE, 3rd, Wang AK, et al. MR Imaging of Spinal Cord and Vertebral
Body Infarction. AJNR 1992; 13:145-154.
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