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Evaluating Carotid Plaque and Carotid Intima-Media Thickness

Introduction The ultrasound evaluation of carotid artery atherosclerosis has evolved over the years. At the start, B-mode (gray-scale) images were used to evaluate the severity of carotid artery disease in the hope of supplementing traditional arteriography. Unfortunately, it became apparent that at higher degrees of stenosis the diagnostic accuracy of B-mode images was insufficient to estimate fully the severity of carotid artery stenosis. This held true…

Carotid Sonography: Protocol and Technical Considerations

B-Mode Ultrasound of the Normal Carotid Artery Wall The carotid artery wall is composed of three layers: the intima, the media, and the adventitia. The intima is the innermost layer abutting the lumen. It is thin and is covered with a lining of endothelial cells. The media is the middle layer. It contains a preponderance of elastic and connective tissues in the common carotid artery (CCA),…

Anatomy of the Cerebral Structure

Introduction The vascular system of the human brain differs significantly, both anatomically and physiologically, from that of other organs. Although it accounts for only 2% of the body weight, the brain receives 15% of the cardiac output and consumes 20% of the body's oxygen supply in the basal state. Unlike other arteries, the cerebral arteries are little influenced by sympathetic nervous activity, but they respond dramatically…

Doppler Flow Imaging and Spectral Analysis

Introduction In this chapter, we review the concepts and principles necessary for understanding and interpreting color Doppler images and pulsed Doppler waveforms and discuss the key elements needed for the interpretation of Doppler spectral waveforms. This includes a study of normal waveform patterns and characteristic changes that occur with pathologic states. Important tips are given for recognizing Doppler spectral features that are essential for the diagnosis…

Principles and Instruments of Ultrasonography

Introduction This chapter serves as an introduction to the physical and technical aspects of vascular sonography, including the following: (1) ultrasound principles, (2) transducers, (3) instruments, (4) advanced features, and (5) Doppler principles. These subjects are discussed in greater detail in various textbooks. Ultrasound Principles Sound waves are produced by vibrating sources, which cause particles in the medium to oscillate back and forth, setting up the…

The Hemodynamics of Vascular Disease

Overview The human circulatory system is extremely complex. Blood flow is influenced by many factors: 1. The heart influences the strength and amount of ejected blood. 2. The elastic arteries store energy during systole and maintain blood flow during diastole. 3. The muscular arteries maintain tone. 4. The arterioles, capillaries, and the venules supply blood to the different organs. 5. The veins ensure adequate return of…

The Wrist

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The Elbow

Elbow Checklists 1 Radiographic examination AP External oblique Lateral 2 Elbow joint effusions and the fat pad sign Visible posterior fat pad Elevation of the anterior fat pad, the sail sign 3 Common sites of injury in adults Radial head and neck Olecranon Coronoid process of ulna Distal humerus 4 Common sites of injury in children and adolescents Supracondylar of the distal humerus Salter-Harris type 4…

The Shoulder

Shoulder Checklists 1 Radiographic examination AP external rotation AP internal rotation Axillary view Y-view Grashey (posterior oblique) view 2 Common sites of injury in adults Fractures Midshaft of clavicle Avulsion of the greater tuberosity of the humerus Surgical neck of the humerus Dislocations Acromioclavicular joint dislocation Dislocation of the glenohumeral joint Anterior dislocation Posterior dislocation Luxatio erecti 3 Common sites of injury in children and adolescents…

Peripheral Nerve Imaging: The Carpal Tunnel

The most common peripheral nerve compression syndrome is compression neuropathy of the median nerve at the carpal tunnel. The median nerve innervates the wrist and sends cutaneous sensory branches to innervate the palm, the palmar aspect of the first three digits, and the radial half of the fourth digit. The median nerve also innervates the superficial flexors of the first three rays, as well as the…

Imaging of the Sacral Plexus

The sacral plexus and sciatic nerve are formed within the pelvis from contributions of the ventral nerve roots of L4 through S4. The sciatic nerve originates from the sacral plexus within the pelvis and then exits the pelvis through the greater sciatic foramen. Technical advances in the surface coils and pulse sequences used for MRI now make it possible to display the normal anatomy and pathology…

Imaging of the Brachial Plexus

The brachial plexus is the name given to the plexus of nerves formed by the lower four ventral cervical roots (C5-C8) and the first thoracic ventral root (T1) as they emerge from the spinal cord, intermingle, realign, and emerge from the plexus as defined distal nerves. C4 and T2 may contribute axons to the plexus with little effect on the clinical location of the lesion. The…

Complications of Surgery for Decompression of Spinal Stenosis and Disc Disease

Successful surgery for spondylosis and disc disease relieves the initial symptoms and, for cases in which stabilization is performed, provides solid fusion at the operative site. Complications of surgery can include failure to relieve the symptoms, failure of fusion, and any new problem resulting from the surgery itself. General complications of surgery include thrombophlebitis (2%-3%), pulmonary embolism (1%), and death (0.1%-0.3%). Risks of spinal surgery include…

Vertebral Body Augmentation Procedures: Vertebroplasty and Kyphoplasty

Compression fractures of vertebral bodies affect approximately 750,000 people each year in the United States and up to 25% of postmenopausal women. The leading cause of vertebral compression fractures is osteoporosis, a disease that affects 44 million Americans. Younger patients taking corticosteroids for medical problems such as lupus, asthma, and rheumatoid arthritis may also suffer from osteoporotic compression fractures. Other, less common causes of vertebral body…

Intraoperative Neurophysiologic Monitoring

First described more than 40 years ago, intraoperative neurophysiologic monitoring (IONM) is now used routinely in many surgical procedures that carry risk to the brain, spinal cord, and peripheral nervous system. These include closure of intracranial aneurysms and arteriovenous malformations; resections of intracranial tumors; repair of carotid artery disease; relief of spinal compressions caused by degenerative spondylosis, tumor, or trauma; and treatment of spinal vascular malformations.…

Imaging Preparation for Surgery

The spine and the peripheral nervous system remain diagnostically challenging to image owing to the extensive bony canal, relatively small size of the neural elements, and multiplicity of clinical symptoms. A wide variety of techniques are available for imaging the spine. MRI is the procedure of choice for evaluation of many of the musculoskeletal and neurologic diseases of the spine. The musculoskeletal system includes the vertebral…

Inflammation of the Spinal Cord

Noninfectious inflammatory spinal cord lesions include multiple sclerosis (MS), acute transverse myelitis (ATM), neuromyelitis optica (NMO), neurosarcoidosis, and Guillain-Barré syndrome (GBS). Except for MS, these entities are rare. The disease etiologies are incompletely understood but seem to involve immune system activation as a significant event. Recent discoveries, such as the recognition of a serum autoantibody to the membrane protein aquaporin-4 in patients with NMO, have led…

Inflammation of the Spinal Column

Noninfective inflammations of the vertebral spine can be caused by seronegative spondyloarthropathies or by seropositive rheumatoid arthritis. The seronegative spondyloarthropathies include ankylosing spondylitis, psoriatic arthritis, reactive arthritis, arthritis associated with inflammatory bowel diseases, and undifferentiated arthritis. ANYLOSING SPONDYLITIS Epidemiology Ankylosing spondylitis is the most frequent seronegative inflammatory spinal disease in adults and the prototype for other members of the spondyloarthropathies. The prevalence of this disorder is…

Infections of the Spinal Cord

SPINAL MENINGITIS Spinal meningitis is infection of the spinal cord, leptomeninges, and subarachnoid space by various pathogens. It is also called infectious arachnoiditis. Epidemiology The incidence of bacterial meningitis is 2 to 3 per 100,000. It occurs most commonly in newborns, in infants aged 3 to 8 months, and in adults at the second and sixth decades. Spinal meningitis occurs less frequently than intracranial meningitis. Clinical…