 Introduction/Background Myelopathy refers to any pathologic process affecting the spinal cord. It is a clinical diagnosis based on signs and symptoms of spinal cord dysfunction [1]. Myelopathy can be due to primary intrinsic disorders of the spinal cord and include neoplastic, infectious, inflammatory, neurodegenerative, vascular, nutritional, and idiopathic disorders [2]. More commonly, however, myelopathy is due to secondary conditions, which result in extrinsic compression of the spinal cord. The most frequently encountered cause of extrinsic compression of the spinal cord in adults is degenerative disease of the cervical and thoracic spine [3]. Other causes of myelopathy from external spinal cord compression include bone metastases and blunt or penetrating trauma. A variety of cysts and benign neoplasms can also compress the cord; they tend to arise within the intradural compartment. The most common of these are nerve sheath tumors, meningiomas, and arachnoid adhesions/cysts [4-10]. Clinically, the diagnosis of myelopathy depends on the localization of the neurological finding to the spinal cord, rather than the brain or peripheral nervous system, and then to a particular segment of the spinal cord [11]. Although the causes of myelopathy may be many, the acuity of presentation and symptom onset provides the clinical team with a practical approach to the differential diagnosis [1,12]. Myelopathy is considered acute if symptoms begin abruptly or have an onset of days to weeks. Myelopathy with a time course of months to years is considered chronic or progressive. Imaging plays a crucial role in refining the differential diagnosis. Historically, radiological evaluation of myelopathic patients consisted of positive contrast myelography. Later, this evaluation was supplemented by CT and CT myelography. MRI is now the mainstay in the evaluation of myelopathy because of its superb contrast resolution of the spinal cord [10,13-15].
Myelopathy PCAs.  Introduction/Background Myelopathy refers to any pathologic process affecting the spinal cord. It is a clinical diagnosis based on signs and symptoms of spinal cord dysfunction [1]. Myelopathy can be due to primary intrinsic disorders of the spinal cord and include neoplastic, infectious, inflammatory, neurodegenerative, vascular, nutritional, and idiopathic disorders [2]. More commonly, however, myelopathy is due to secondary conditions, which result in extrinsic compression of the spinal cord. The most frequently encountered cause of extrinsic compression of the spinal cord in adults is degenerative disease of the cervical and thoracic spine [3]. Other causes of myelopathy from external spinal cord compression include bone metastases and blunt or penetrating trauma. A variety of cysts and benign neoplasms can also compress the cord; they tend to arise within the intradural compartment. The most common of these are nerve sheath tumors, meningiomas, and arachnoid adhesions/cysts [4-10]. Clinically, the diagnosis of myelopathy depends on the localization of the neurological finding to the spinal cord, rather than the brain or peripheral nervous system, and then to a particular segment of the spinal cord [11]. Although the causes of myelopathy may be many, the acuity of presentation and symptom onset provides the clinical team with a practical approach to the differential diagnosis [1,12]. Myelopathy is considered acute if symptoms begin abruptly or have an onset of days to weeks. Myelopathy with a time course of months to years is considered chronic or progressive. Imaging plays a crucial role in refining the differential diagnosis. Historically, radiological evaluation of myelopathic patients consisted of positive contrast myelography. Later, this evaluation was supplemented by CT and CT myelography. MRI is now the mainstay in the evaluation of myelopathy because of its superb contrast resolution of the spinal cord [10,13-15].