Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Atrophy

3.6.1 Historical Perspective Since the early days of X-ray computerized tomography (CT) in the late 1970s, it has been possible to visualize the spinal cord in cross-section in vivo, and to make quantitative measurements of the cord diameter. Early studies required the introduction of an iodinated contrast agent into the cerebrospinal fluid (CSF) by means of a lumbar puncture, in a procedure known as computed myelography.…

T 2 Relaxation

3.5.1 Overview T 2 -weighted imaging plays a key role in clinical MR imaging of spinal cord. While T 2 weighting is highly sensitive, it is notoriously unspecific as very different pathological conditions can lead to similar increases in water content that result in similar T 2 increases. Therefore, T 2 -weighted imaging should be considered a qualitative clinical tool; however, if the full T 2…

Magnetization Transfer

Magnetization transfer (MT), first demonstrated in vivo by Wolff and Balaban, is a contrast mechanism based on the exchange of magnetization occurring between groups of spins characterized by different molecular environments. MT produces a source of contrast alternative to T 1 and T 2 , which has become widely used in clinical imaging to improve the suppression of static tissue in MR angiography and to increase…

Advanced Methods to Study White Matter Microstructure

3.3.1 Introduction: Diffusion Imaging and Tissue Microstructure Diffusion imaging and particularly diffusion tensor imaging (DTI) have become standard tools for assessment of white matter in the brain. Although somewhat more technically challenging to implement in the spinal cord, these methods are now also commonplace in studies of the spinal cord. DTI provides two unique pieces of information over any preceding method. First, it provides an estimate…

Q -Space Imaging: A Model-Free Approach

In Chapter 3.1 , the diffusion of water molecules was described according to the diffusion tensor model, which assumes a Gaussian probability of displacement associated to the diffusion of water molecules. This assumption is true in free systems, but it is also applied for water in complex biological structures. In this chapter, the q -space theory is explored as a model free from assumptions, and we…

Diffusion-Weighted Imaging of the Spinal Cord

3.1.1 Principles of Diffusion-Weighted Magnetic Resonance Imaging 3.1.1.1 Basic Concept of Diffusion Weighting Water molecules in tissue undergo Brownian motion, which means that molecules are not perfectly static over time but experience random microscopic displacements due to thermal agitation. This effect can be characterized by a diffusion coefficient. Compared to free water, where this effect is equal whatever the direction of observation is (i.e., it is…

Ultra-High Field Spinal Cord Imaging

2.4.1 Background 2.4.1.1 Importance of High Field In the early 1980s, magnetic resonance imaging (MRI) was introduced into clinical practice and has subsequently undergone technical advancements that have resulted in improvements in image quality. For nearly 20 years, 1.5 T has been the most common field strength in use for clinical MRI of the human spinal cord. In fact, according to current European Union regulations, scanners…

Susceptibility Artifacts

2.3.1 Introduction: Sources of Susceptibility Artifacts The uniformity of the B 0 main field in magnetic resonance imaging (MRI) is critical for artifact-free image formation. MRI scanners are manufactured with a stringent requirement of less than one part-per-million (ppm) a a In MRI, the variations in B 0 field or the differences in resonant frequencies are so small that they are expressed in “parts per million”,…

B 0 Inhomogeneity and Shimming

Acknowledgments The author is very grateful to Susann Boretius, Martin Busch, Yasar Goedecke, Martin Koch, Joost Kuijer, Marco Lawrenz, and Petra Pouwels for helpful discussions and to Joachim Graessner (Siemens Healthcare) and Jürgen Bunke (Philips Healthcare) for providing information about the shim techniques of their companies' MR systems. In the context of magnetic resonance (MR) experiments, “shimming” describes the procedures performed to provide a sufficiently homogeneous…

Array Coils

2.1.1 Introduction Essential parts of a magnetic resonance imaging (MRI) system, radiofrequency (RF) coils or antennas are used to transmit and/or receive signal. Phased-array coils combine multiple small coil elements to transmit or receive signal using independent channels. Array coils were first described in a seminal paper by Roemer et al., and proof-of-concept was demonstrated in the spine. Since then, array coils have become the standard for…

Traumatic Spinal Cord Injury: Chronic Spinal Cord Injury and Recovery

1.3B.1 Introduction The introduction of magnetic resonance imaging (MRI) to the field of spine trauma has vastly improved the clinical diagnosis of spinal cord injury (SCI). MRI has advantages over conventional X-ray and computer tomography (CT) as it more precisely details posttraumatic compression of the spinal cord, either due to soft tissue (i.e., traumatic disc herniation or bleeding within the spinal canal) or spinal canal encroachment…

Traumatic Spinal Cord Injury: Acute Spinal Cord Injury and Prognosis

1.3A.1 Introduction Prior to the 1980s a diagnosis of trauma to the spinal cord was largely inferred based on either X-rays showing misalignment of the spinal column or myelography whereby interruption of the flow of contrast medium in the cerebral spinal fluid (CSF) space indicated impingement of the spinal cord. With the widespread adoption of MRI came the visualization of the spinal cord itself, and along…

Inflammatory Demyelinating Diseases

1.2.1 Introduction The spinal cord is a common site of involvement in inflammatory demyelinating diseases of the central nervous system (CNS). The most common such disease, multiple sclerosis, is the leading cause of nontraumatic disability in young adults, with an enormous socioeconomic impact. Neuromyelitis optica (NMO), an increasingly recognized and recently redefined condition, also has prominent and very characteristic spinal cord involvement, which is typically much…

Rationale for Quantitative MRI of the Human Spinal Cord and Clinical Applications

1.1.1 Introduction Neuroaxonal injury of the spinal cord occurs in a broad spectrum of clinically and pathologically heterogeneous neurodegenerative diseases, typically with serious clinical consequences for patients. Typically, the clinical syndrome produced by injury to the spinal cord includes weakness or paralysis of the limbs and trunk, with sensory disturbance and dysfunction of the gastrointestinal and genitourinary sphincters. The spinal cord is therefore an important region…

Imaging of Back Pain

Acknowledgments I acknowledge Brad Hoehne, Radiology Digital Imaging Specialist (Nationwide Children’s Hospital), for preparation of figures. Back pain is common in children and tends to increase with age, especially in the early teen years. Although back pain can be the presenting symptom of serious pathology, such as infection or neoplasm, recent studies have shown lower rates of identifiable disease in children with back pain. A nonpathological…

Neonatal Spine Imaging

In the neonatal period the most frequently encountered spinal pathologies are of developmental nature. Spinal tumors or infections are exquisitely rare in neonates. Spinal trauma may occasionally be encountered and typically result from a complicated/traumatic delivery. This chapter will consequently focus on spinal malformations. The development of the spinal canal and its contents is highly complex and involves multiple “programmed” anatomic and functional developmental and maturational…

Imaging of the Pediatric Cervical Spine

The most common indication for pediatric cervical spine (C-spine) imaging is trauma. Although cervical spinal injuries are rare in children, the result can be devastating. The role of the radiologist is crucial in the early detection of cervical spinal injury (CSI) that may require immediate clinical attention. Imaging interpretation of the C-spine is particularly challenging and requires a thorough knowledge of its unique anatomic characteristics as…

Pediatric Head and Neck Masses

Evaluation of pediatric head and neck masses can be challenging because the anatomy is complex and the diseases that affect the head and neck are numerous. Grouping head and neck lesions into broad categories based on anatomic location and suspected type of lesion, whether it is solid or cystic, can greatly facilitate a practical approach to imaging. For small, superficial lesions in the neck, ultrasound is…

Approach to Lateral Neck Radiographs

Approach to the Lateral Neck Radiograph The lateral neck radiograph is a relatively inexpensive, readily available, and easy-to-perform examination that is very useful for the evaluation of suspected abnormalities in the upper aerodigestive tract. In the emergency setting the lateral neck radiograph is commonly obtained to evaluate for abnormalities causing acute respiratory distress or dysphagia. The examination also can be useful in the workup of chronic…

Pediatric Head CT

Introduction Neuroradiological imaging of the pediatric patient has undergone tremendous change since the late 2000s. Although the use of magnetic resonance imaging (MRI) is on the rise, in part because of concerns over exposing children to medical radiation, there is still an important role for pediatric head computed tomography (CT), which provides fast imaging, often without the need for sedation. CT therefore remains an important tool…