Seminars in Ultrasound Ct and Mri最新文献

For a long time, technical obstacles have hampered the acquisition of high-resolution images and the development of reliable processing protocols for spinal cord (SC) MRI. Fortunately, this scenario has changed in the past 5-10 years, due to hardware and software improvements. Nowadays, with advanced protocols, SC MRI is considered a useful tool for several inherited and acquired neurologic diseases, not only for diagnosis approach but also for pathophysiological unraveling and as a biomarker for disease monitoring and clinical trials. In this review, we address advanced SC MRI sequences for macrostructural and microstructural evaluation, useful semiautomatic and automatic processing tools and clinical applications on several neurologic conditions such as hereditary cerebellar ataxia, hereditary spastic paraplegia, motor neuron diseases and multiple sclerosis.

Ankle sprains are among the most common musculoskeletal injuries and can lead to ankle ligament and cartilage injuries. Imaging plays an important role in differentiating ligament injuries from other causes of ankle pain such as fractures, osteochondral lesions or tendon injuries that helps guide further management. Chronic untreated ankle ligamentous and cartilage injuries can further progress to ankle osteoarthritis, hence the need for timely diagnosis and treatment. Surgical treatment is often required in patients not responding to conservative treatment and ranges from repair and reconstruction procedures for ligament injuries to arthroscopic debridement and repair procedures for cartilage injuries. Cartilage defects and deficiency may be augmented depending on the extent of cartilage loss and associated subchondral changes on MRI. Awareness of operative techniques utilized is essential to interpret imaging findings in postoperative settings.

The Neuropathy Score Reporting and Data System (NS-RADS) is a newly developed MR imaging-based classification that standardizes reporting and multidisciplinary communication for MR imaging diagnosis and follow-up of peripheral neuropathies. NS-RADS classification has shown to be accurate and reliable across different centers, readers' experience levels, and degrees of peripheral neuropathies, which include nerve injury, entrapment, neoplasm, diffuse neuropathy, post-interventional status, and temporal changes in muscle denervation. This article brings a practical review of NS-RADS classification, representative MR cases, and a step-by-step tutorial on how to approach this staging system. Readers can gain knowledge and apply it in their practice, aiming to standardize the communications between specialties and improve patient management.

With an increasing life expectancy of global human population, there is a growing demand for preservation of native articular meniscus and cartilage to delay joint arthroplasties, especially in younger and active patients. Since damage to the meniscus and hyaline cartilage of the knee have limited intrinsic capacity to heal, such lesions lead to premature and/or accelerated osteoarthritis. However, knee surgical treatments have evolved and may allow restoration of the natural anatomy, delay the progression of damage, and alter the biology of the meniscus and articular cartilage. The knee preservation surgery is aided by timely detection of such injuries and high-resolution illustration and characterization of the pathology using two-dimensional and three-dimensional magnetic resonance imaging (MRI), made possible due to better MR scanner technology and related software improvements. This article reviews the current literature and authors’ experience with imaging concepts and high-resolution MR imaging techniques as they relate to management and planning for such restorative procedures. Relevant arthroscopy correlations have been illustrated.

Common hip internal derangements include femoroacetabular impingement (FAI), developmental dysplasia of hip (DDH) dysplasia, and avascular necrosis (AVN) of the femoral head. These are initially screened by radiographs. For preoperative planning of hip preservation, 3-dimensional (3D) CT is commonly performed to assess bony anatomy and its alterations. Magnetic resonance imaging (MRI) is used to evaluate labrum, hyaline cartilage, tendons, synovium, and loose bodies, and provides vital information for surgical decision-making. However, conventional 2D MRI techniques are limited by lack of isotropic multiplanar reconstructions and partial volume artifacts. With advancements in hardware and software, novel isotropic 3D MR Proton Density images are acquired with acceptable acquisition times leading to improved visualization of soft tissue and osseous structures for various hip conditions. Three-Dimensional MRI allows multiplanar non-gap reconstructions along the structures of interest. It results in detection of small, otherwise inconspicuous labral tears without the need for MR arthrogram, which can be subsequently measured. In addition, radial reconstructions of the femoral head can be performed from original 3D volume MR imaging and CT imaging without the need for individual different plane acquisitions. Three-Dimensional MRI thus impacts surgical decision-making for the important common hip derangement conditions. For example, femoral head hyaline cartilage loss may make hip preservation difficult or impossible. In this review, we discuss the advantages and technical details of 3D CT and MRI and their significant role in aiding hip preservation surgery for common hip conditions. The conditions discussed in this article include FAI, DDH, AVN, synovial disorders, cartilaginous tumors, and hip fractures.

A comprehensive understanding of the anatomy and biomechanics of muscle fibers and tendons is crucial to comprehend their functions. The orientation of tendon fibers plays a significant role in the pathologies that affect them and the resulting functional impairments. In this review, we provide detailed information on the origin, insertion, and fiber orientation of selected muscles and tendons, as well as their functional significance. To aid in comprehension, we have included illustrations depicting the anatomy and fiber orientation, as well as cross-sectional MR images that highlight important imaging features of normal anatomy and tears of select lower extremity tendons.

Being a major load-bearing and dynamic functional joint of the body, the knee joint is prone to injuries to the menisci and ligaments. Injury to one or more of these structures leads to accelerated or premature osteoarthritis and chronic debilitation. The estimated cost of these injuries in terms of diagnosis, treatment, rehabilitation, and person-hours lost amounts to over a billion dollars annually. Understanding the relevant anatomy of knee cruciate and collateral ligaments, their biomechanical functional role, and imaging considerations are essential to assist multi-disciplinary communications and timely patient treatments for improved management. MRI is considered the gold standard over other imaging modalities like X-ray, ultrasound (US), and Computed Tomography (CT) for diagnosing and assessing such injuries. High-resolution 2D and 3D MRI are considerably helpful in planning for knee preservation surgery, and this article reviews the role of such imaging as a valuable aid to knee preservation surgery in pre-and post-operative states. Relevant arthroscopy correlations have been illustrated.

Total hip arthroplasty is an effective treatment for severe degenerative arthritis and is increasingly being used. Radiography is the primary modality for the initial diagnosis of osteoarthritis and preoperative planning. Additional radiographic views may include the spine and lower extremities in order to optimize implant positioning for the individual patient. Computed tomography is sometimes used for preoperative planning and intraoperative robotic assistance. Magnetic resonance imaging and diagnostic ultrasound is generally reserved for patients without obvious arthritis. Ultrasound-guided injections may provide diagnostic and/or therapeutic benefits.

Peripheral nerve injury is a common sequela of lower extremity trauma. Injuries to lower extremity nerves range from contusions and stretch injuries that will often resolve without interventions to traumatic disruptions requiring surgical procedures, including neurolysis, repair or even nerve grafting. While clinical examination and tools such as electromyography will often help to localize the site of injury, imaging is a critical tool in determining the extent and degree of nerve injury in the setting of trauma. Modalities such as ultrasound and radiography are often useful, but MRI is considered the primary imaging modality for assessing the extent and degree of nerve injury. Specialized techniques such as MR neurography tailored to the needs of individual patients can provide important and detailed information in support of clinical decision making and presurgical planning. In this paper, we will review the anatomy of peripheral nerves of the lower extremity, mechanisms of injury affecting nerves and provide guidance for the use of MRI correlated with validated classification systems in assessing injuries affecting the nerves of the lower extremities.