E³ 1019 - Spinal cord abnormalities
Spinal imaging is a very wide and challenging topic and requires an integrated approach of clinical data, traditional and so-called advanced protocols. The objective of this academies course is to provide a deep and comprehensive discussion of the different fields of the spine/spinal cord pathology that are more frequently observed in clinical practice. The aim of the organizers was to provide a complete discussion on how to integrate the technical aspects of MRI examination of the spinal cord, the MRI semeiotics of both intradural extramedullary and intramedullary lesions, and the “pattern” approach to intramedullary lesions, to ultimately offer a helpful overview of the spinal pathologies that a radiologist may encounter during his professional career. Prof. Van Goethem will address the technical aspects of the MRI study of the spinal cord, discussing how to exploit MRI ranging from the basics to the most updated state-of-the-art techniques. He will specifically discuss the importance to include the “advanced” techniques in the evaluation of the spinal cord diseases. In the second lecture, Dr. Lycklama will discuss the fundamental topic of differential diagnosis between intra- and extra-medullary tumours, discussing semiotic, pathology and MR features. Finally, during the closing lecture, Prof. Turner will address one of the most difficult scenario that a neuroradiologist may deal with, non-tumoural spinal cord lesions, with the objective to make the audience familiar with the “pattern” approach, with whom, at least, reduce the number of differential diagnosis.
1. To understand the challenges for acquiring high-quality MR images of the spinal cord.
2. To learn current state-of-the-art sequences for spinal cord imaging.
3. To be aware of the importance of advanced neuroimaging techniques for the evaluation of spinal cord diseases.
Magnetic resonance imaging (MRI) of the spinal cord is challenging in many ways. The spinal cord is a small structure and is located in an environment prone to artefacts. I will cover many types of artefacts, including truncation artefacts, motion artefacts caused by breathing and swallowing, CSF pulsation artefacts, aliasing artefacts, susceptibility artefacts and radiofrequency artefacts. The origin of these artefacts and the countermeasures that can be taken will be discussed. I will also provide an overview of the different sequences that should be used in basic and advanced spinal cord imaging, briefly touching upon diffusion and perfusion imaging, spectroscopy and fMRI of the spinal cord.
1. To understand how to differentiate intradural-extramedullary mass lesions from intrinsic spinal cord tumours.
2. To become familiar with the most common types of tumours arising within the spinal canal, both in children and in adults.
3. To learn the typical MR imaging features of these lesions.
Intradural lesions are primarily characterized by their location: intra- vs extramedullary. Intramedullary tumours will expand the spinal cord, while extramedullary lesions will deform it. MRI workup should include high-resolution axial T2 (for example, CISS) to better differentiate intra- from extramedullary. Susceptibility sensitive images show blood products as found, for example, in ependymoma and cavernoma. In addition, MRA may be useful, for example, to demonstrate vessels in a haemangioblastoma. Repeat MRIs are often needed to make a diagnosis and to rule out 'tumour mimickers'. The most common intramedullary tumour in adults is ependymoma. Usually they present with an enhancing component, some haemorrhage and cysts, and for the surgeon it is important to define the cystic components into tumour cyst, peritumoural cyst and secondary syringomyelia. Usually, the whole neuraxis is imaged to detect 'drop' metastases. In children, spinal cord tumours are very rare, and when occurring, astrocytoma is the most common - presenting with less strong enhancement and more vaguely defined than ependymoma. Other primary spinal cord tumours are rare - and 'tumour mimickers' should always be considered. Extramedullary tumours are most often benign: meningioma and Schwannoma. These can usually be distinguished by their growth pattern and signal characteristics, Schwannoma usually following the nerve root into the neuroforamen and expanding it. Other extramedullary lesions include metastasis, haemangioblastoma and cavernoma. It is, however, important to realize that some tumours which usually occur extramedullary, may also occur within the cord, for example, Schwannoma and haemangioblastoma.
1. To become familiar with the epidemiology and clinical manifestations of the most common diseases affecting the spinal cord.
2. To recognise the most common intramedullary lesions.
3. To learn how to identify these lesions based on the pattern of involvement.
The choice of strategy for diagnostic problem solving depends on the perceived difficulty of the case and on knowledge of content. The list of non-tumoural pathology affecting the spinal cord includes demyelinating, vascular, metabolic and degenerative conditions. However, MR imaging findings are overlapping and sometimes confusing. Knowledge of coexisting brain lesions is crucial for narrowing the differential diagnosis. Clinical information (onset of symptoms, history of travels, immune status, etc.) will be helpful to confirm or exclude specific diagnoses. In this lecture, a simplified approach including tips and tricks to non-tumoural spinal cord lesions will be presented.