This successful series on aspects of medical radiology has already covered several musculoskeletal topics. In the present edition, the editorial team has again chosen international experts to contribute chapters on their particular field of interest, ensuring that high standards are continued. The book is divided into initial chapters presenting the state of the art description of all of the different imaging techniques and procedures applicable to the pelvis.
This is followed by individual chapters on conditions specific to the pelvis including all of the pediatric hip conditions, pelvic trauma and soft tissue injuries. Kindle Cloud Reader Read instantly in your browser. Product details File Size: Springer; edition December 29, Publication Date: December 29, Sold by: Related Video Shorts 0 Upload your video. Customer reviews There are no customer reviews yet. Share your thoughts with other customers. Write a customer review. Amazon Giveaway allows you to run promotional giveaways in order to create buzz, reward your audience, and attract new followers and customers.
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Techniques and Applications Medical Radiology. Set up a giveaway. Feedback If you need help or have a question for Customer Service, contact us. Would you like to report poor quality or formatting in this book? Children older than 6 months usually are too large to tolerate a brace. Closed reduction under general anesthesia is usually attempted first. Plain radiographs of the pelvis are obtained in the frontal projection with the legs in the neutral position. Before the femoral heads begin to ossify, the projected locations must be estimated.
Line measurements made on the anteroposterior radiograph help determine the relationship of the femoral head with the acetabulum. See the image below. The acetabular angle is determined by first drawing the Hilgenreiner or Y-Y line, which is a horizontal line between the 2 triradiate or Y-Y cartilages, and then drawing a second line connecting the superolateral and inferomedial margins of the acetabular roof, as Kirks and Griscom reported. The angle decreases gradually with age as a result of modeling of the acetabulum by the femoral head and of the maturation of developing bone along the superolateral acetabular roof.
The acetabular angle is often increased in DDH because maturation and ossification of the acetabulum are abnormal and delayed. The Perkins line is drawn at the outer acetabular margin and is perpendicular to the Hilgenreiner line. These lines divide the hip into quadrants. The unossified femoral head normally is centered in the inferomedial quadrant. In the normal hip, the Shenton line is a smooth, unbroken arc that bridges the medial femoral metaphysis and the inferior edge of the superior pubic ramus. Displacement of the femoral head out of the joint space and disruption of the Shenton line are suggestive of DDH.
Delayed ossification of the femoral epiphysis is observed in the unstable hip. A false acetabulum eventually develops secondary to molding of the displaced ossification center against the bony pelvis. To assess reducibility, a frontal view of the pelvis can be obtained with the legs in external rotation ie, frog-leg position. Plain radiography has a low sensitivity, exposes the infant to ionizing radiation, and does not provide dynamic information. Radiographs are difficult to interpret before the capital femoral epiphyses ossify.
Because some hips may be subluxatable but not frankly dislocated or dislocatable only with Barlow maneuvers, plain radiographs obtained in neonates or infants with their hips in the neutral position frequently fail to depict DDH. Computed tomography CT is useful for evaluating complicated dislocations and for postoperative evaluation of the hip. CT can depict osseous blocks to relocation, as well as iliopsoas tendon capsule constriction, a thick ligamentum teres, and fibrofatty pulvinar hypertrophy.
CT can also be used to evaluate femoral and acetabular anteversion. In infants with spica casts, low-milliamperage selective thin-section CT sections can confidently and quickly assess concentric reduction before the patient is discharged.
MRI can be useful in the preoperative and postoperative evaluation of a hip with many complications. MRI can be used to distinguish the labrum, capsule, and acetabular cartilage. MRI can also be used to demonstrate iliopsoas tendon compression, a thick ligamentum teres, and pulvinar hypertrophy. A high-resolution linear array transducer must be used.
The operator uses one hand to hold the infant's knee at a right angle to the thigh.
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The palm of an open hand may be placed on the small of the infant's back. The thigh is held in the neutral position for imaging. The unossified cartilaginous femoral head appears as a speckled ball in the acetabular fossa. Once ossification begins, it appears as a central area of increased echogenicity in the center of the cartilaginous head. The femoral head should be centered in the joint space, with half or more of the femoral head medial to the baseline in the coronal plane. The extent of maturity of the acetabulum can also be quantified by using angular measurements see the image below.
Imaging of the hip & bony pelvis: techniques and applications
The ACR considers the calculation of these measurements optional. The standard coronal sectioning plane must be used at the deepest portion of the acetabulum, where the ilium appears as a straight line, perpendicular to the femoral head and parallel to the surface of the transducer. To quantify acetabular maturity, alpha and beta angles are determined by the application of 3 lines drawn in the standard coronal plane see the image below. The baseline passes through the plane of the ilium, where it connects to the osseous acetabular convexity.
The inclination line passes from the lateral end of the acetabulum to the labrum, parallel to the cartilaginous roof. The roofline passes along the plane of the bony acetabular convexity. The alpha angle is used most commonly as a measurement of acetabular concavity, and it is calculated as the angle between the baseline and the roofline.
Imaging of the Hip & Bony Pelvis: Techniques and Applications - Google Книги
The beta angle is measured between the baseline and the inclination line. It indicates the acetabular cartilaginous roof coverage. The smaller the angle, the less the cartilaginous coverage and the better the bony acetabular coverage of the femoral head. Not all dynamic hip imagers use these angles for the diagnosis and care of babies with DDH. Many use descriptive terms instead of numbers. This ratio represents the coverage of the femoral head by the bony acetabulum in the standard coronal plane see the image below.
The smaller the coverage, the greater the acetabular immaturity. The use of stress is optional in coronal imaging, which may be performed with the patient's leg in a flexed or neutral position.
Imaging in Developmental Dysplasia of the Hip
Stress is omitted if the infant is receiving treatment for DDH with a Pavlik harness. Stress maneuvering reveals instability, subluxation see the third image below , or dislocation see the fourth image below. In dislocated hips, the Ortolani maneuver should be performed to check for reducibility. An ancillary sign of instability is asymmetry in the degree of ossification of the femoral heads. Mild instability may be observed in healthy neonates in their first few days of life, when the typical femoral head has a laxity of mm on average.
This amount of motion should resolve spontaneously within the first months of an infant's life, after maternal hormonal influences diminish. Inexperienced US examiners can mistake the greater trochanter cartilage for the femoral head and incorrectly diagnose developmental dysplasia of the hip DDH. It has been suggested that, because US is very sensitive, a plain radiograph be performed to confirm DDH in infants over the age of 4 months with abnormal static US examinations, as ossification of the capital femoral epiphyses would begin to be present, thereby limiting overtreatment.
This unnecessary exposure to ionizing radiation, however, can be avoided by the performance of a dynamic US examination.