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Given the variety of potential types of pathology and their varied clinical presenta- tions, spinal emergencies are considered among the most challenging of all neuroradiological investigations. Spinal emergencies can be divid- ed into traumatic and non-traumatic causes and can involve the spinal column itself and its re- lated bony, ligamentous and muscular tissues, as well as the intraspinal contents to include the meninges, spinal roots/nerves and spinal cord.
Non-traumatic spinal emergencies can origi- nate from a vast number of causes. These non- injury lesions of the spine are classified as be- nign/malignant neoplastic (primary or metasta- tic, including haematological malignancies) or infectious-degenerative. Lesions of the spinal contents may be extradural (e.g., haematoma, infection), intradural-extramedullary (e.g., pri- mary or secondary neoplasia) or intramedullary (e.g., infarction, haemorrhage, demyelinating plaque formation) in location.
NEURORADIOLOGICAL PROTOCOLS
From a clinical point of view, the most im- portant crisis whatever the cause is the presen- tation of a patient with signs and symptoms suggesting compression of the spinal cord and the spinal nerve roots. In this case, the neuro-
radiologist’s role is to identify the cause of the clinical presentation quickly so that decom- pression of the compromised neurological tis- sue can be undertaken in a timely manner: the earlier the diagnosis, the greater is the proba- bility of functional recovery following therapy.
For this purpose a number of imaging methods can be used, depending upon the specific clini- cal situation.
Conventional radiography is still considered the first technique of choice in spinal emergen- cies, despite the fact that it is not always con- clusive, especially in the more complex cases of spinal pathology. Considering its low cost, uni- versal patient access and its rapidity and sim- plicity of execution, conventional radiography provides a general diagnostic evaluation, re- vealing the majority of pathological spinal con- ditions responsible for the compression of the spinal cord and the nerve roots.
The subsequent diagnostic imaging modali- ty chosen varies depending on the presence and nature of the neurological signs and symptoms indicating direct involvement of neural struc- tures. In cases where neurological symptoms are present, MRI is preferable to CT where it is available (1, 3-5, 9-11). By combining multipla- nar capabilities and high sensitivity to subtle tissue abnormalities, MR provides a very thor- ough analysis of the spinal column, its contents
5.1
CLINICAL AND DIAGNOSTIC SUMMARY
T. Scarabino, M.G. Bonetti, M. Cammisa
and the perivertebral soft tissues. In general, MRI provides information non-invasively that it currently unobtainable using other imaging techniques.
Given its high sensitivity, MRI is capable of visualizing bone marrow abnormalities earlier than other imaging techniques. In addition to limited access in some areas, there may also be practical drawbacks to the use of MRI, espe- cially in patients with acute vertebral collapse and spinal cord compression. Life support de- vices in such patients, for example, may pre- clude the use of MRI.
If MRI is unavailable or it is not technically possible, CT can provide useful information re- garding bony morphology, the central spinal canal and the perispinal soft tissues (2, 4, 8).
However, CT provides little data concerning the contents of the central spinal canal. Neverthe- less, intervertebral disk herniations and verte- bral compressions/burst fractures of traumatic origin are well visualized (7). In such instances the examination can be performed quickly, without having to immobilize the patient. In ad- dition, CT investigations can be extended to in- clude other organs and regions in polytrauma patients, providing results that are unquestion- ably superior to and more informative in most cases than those obtained with conventional ra- diography. Of course, in order to avoid exces- sive irradiation the CT examination should be focused on limited levels of the spine by the pre- liminary identification of problem areas by means of x-ray or MRI, or on the basis of spe- cific localizing clinical signs and symptoms.
It is not always possible to clearly define the location of the pathology responsible for the clinical presentation. In such cases, MR is once again the most reliable examination technique,
as it clearly defines the spinal pathology re- sponsible for the neural compromise, analysing at once the epidural space, the intradural-ex- tramedullary space and the spinal cord (16). To repeat, CT’s principal drawback in this regard is its inability to visualize the intradural struc- tures (7).
In conclusion, MRI currently represents an indispensable instrument in spinal diagnosis. In certain cases it enables a complete diagnostic evaluation even when used alone. In other cas- es it can be combined profitably with other conventional neuroradiological techniques to facilitate a definitive diagnosis.
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298 V. SPINAL EMERGENCIES
