E-Book, Englisch, 1136 Seiten, ePub
E-Book, Englisch, 1136 Seiten, ePub
ISBN: 978-3-13-257826-5
Verlag: Thieme
Format: EPUB
Kopierschutz: 6 - ePub Watermark
Is a radiological finding normal or pathologic? This "borderline" between the two states presents a daunting challenge to radiologists and orthopedic surgeons on a daily basis. Thieme proudly presents the updated and expanded fifth edition of the landmark text generations of physicians have used to differentiate borderline findings!
Redesigned for optimal use, the book is organized according to diagnostic questions raised by clinical findings, radiographic findings, or both. You'll find all possible variants in five pathologic categories: anomaly; trauma; necrosis; inflammation; and tumor. The book provides imaging examples of the entire body, from the skull base, shoulder, and clavicle, to lower spine, knees, and the feet. More than 4,200 high-quality illustrations give clear examples of potential findings.
Key features of this historic text:
- Illustrated with more than 4,200 outstanding drawings, photographs, and radiographs--nearly 4 per page! - Full coverage of pathologic conditions in their fully developed form, - Exhaustive analysis of borderline findings for both pediatric and adult cases - Valuable guidelines on integrating pathologic conditions with CT and MRI findings
This book is the encyclopedic resource that will expand your knowledge of findings in skeletal radiology and enhance your diagnostic skills. No personal or professional library is complete without this new standard-bearer in the field!
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Autoren/Hrsg.
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Weitere Infos & Material
1 Introduction to the Radiological Evaluation of Normal Variants2 Upper Extremity
The Hand
Forearm
Elbow Region
Upper Arm
3 Shoulder Girdle and Thorax
Scapula
Acromioclavicular Joint
The Shoulder Joint as a Whole
Clavicle and Sternoclavicular Joint
Sternum
Ribs
4 Skull
Cranial Vault
Skull Base
Facial Skeleton
5 Spinal Column
Atlas and Axis
Midcervical and Lower Cervical Spine
Thoracic Spine
Lumbar Spine
Sacrum and Coccyx
Sacroiliac Joints
6 Pelvis7 Lower Extremity
Femur
Patella
Proximal Tibia and Fibula
Knee Joint as a Whole
Shaft of the Tibia and Fibula
Distal Tibia and Fibula
Foot
The differentiation of a normal anatomic variant from a skeletal abnormality based on empirical visual assessment is not the real problem in the diagnostic radiology of borderline findings between normal and early pathology. This problem arises only when a patient's clinical symptoms may have something to do with the radiological variant, or when the variant itself may harbor pathological changes (e.g., necrosis), or when a pathological process mimics a normal anatomic variant (Table 1.1). The problems in this situation cannot be solved by visual assessment alone. The solution, rather, lies in the true art of medicine, which includes the interpretation of pain and neurological symptoms and the selection of further diagnostic procedures (such as radionuclide scanning or MRI). It may also include recommending an appropriate treatment. We know from experience that routine radiographic examinations in hospital and office settings most often demonstrate normal findings along with more or less harmless normal variants. Unless the radiologist is familiar with this type of finding, there are likely to be numerous false-positive studies leading to unnecessary additional (and costly)diagnostic and therapeutic measures. At the same time, the prevalence of normal findings and harmless normal variants in routine practice can engender a kind of complacency that makes it hard for radiologists to recognize a symptomatic normal variant or even a definite abnormality that is mimicking a normal variant. In any given case, therefore, the following question should be added to the standard checklist or algorithm for radiographic interpretation: Is it possible that the normal variant is clinically significant, or is a supposed normal variant actually a pathological process? How Can These Pitfalls Be Avoided? The basic approach to radiological interpretation follows the principles of pattern recognition. The basic criteria for image interpretation in conventional radiography and computed tomography (CT) are as follows: • Shape • Size • Position relative to surrounding structures (topography) • Symmetry • Density In a radionuclide bone scan, the regional degree of tracer uptake is evaluated in addition to the basic interpretive elements of shape, size, topography, and symmetry. Most of the skeletal disorders discussed are associated with an increase in radiotracer uptake. An increase in uptake means only that bone turnover or metabolism in a given area is increased or that the radiotracer has a greater affinity for the pathological process than for surrounding tissues. The cause of the increased uptake may be a traumatic, neoplastic, necrotic, or inflame-matory process. Nevertheless, a radiologist with some experience in osteology and the recognition of radionuclide patterns can often establish the identity of a lesion. A whole-body scintigram should always be obtained, if necessary using SPECT (single-photon emission computed tomography) and a pinhole collimator. In magnetic resonance imaging (MRI), the signal intensity in various sequences replaces density as a basic criterion for image interpretation. In projection radiography (plain film or digital), which still accounts for more than 80% of all radiological studies, projection geometry and the superimposition effect are additional key elements in interpreting radiographic films. Projection geometry influences shape, size, and topography, while the superimposition effect mainly influences density. Superimposition refers not only to the superimposed projection of several bones or bony elements but also to the summation of internal or substructures contained within a single bone. Thus, while a bony ridge produces a linear density in an orthograde projection, a bony groove or canal appears as a linear lucency. Plain radiographs of a cancellous bone area are never identical, because the slightest rotation of the bone relative to the film plane (even by 1° or 2°) will significantly after the projection of the individual bony trabeculae and may cause them to appear thickened. If two bony elements of different density are superimposed, an effect called the Mach band phenomenon occurs, creating a line of apparent radiolucency that is comparable to an optical illusion. In zones of contrasting radiographic densities, areas of higher density are perceived as being darker while areas of lower density appear lighter. The various changes of the individual elements of pattern recognition and their combination ultimately determine how a particular skeletal abnormality will be classified. The basic categories of skeletal abnormality that are encountered in radiological practice are listed below: • Anomaly (malformation, deformity) • Fracture, subluxation, or dislocation • Necrosis • Inflammation • Tumor Of course, changes in pattern recognition criteria do not create a pathological entity—the reverse is true. Nevertheless, the process of radiological interpretation always follows this “reverse path.” So whenever a radiograph shows what appears to be a variant, it is important to ask whether the questionable feature might possibly be a component or manifestation of a fracture, necrosis, inflammation, etc. The following cases will help to illustrate these points. • An isolated bony element at the end of the acromion (Fig. 3.34) raises various diagnostic possibilities. It may be an acute or old nonunited fracture or a persistent apophysis with no clinical significance, or its shape and position may be such that it predisposes to rotator cuff impingement. In making this differentiation, it is important to consider the history and clinical findings. An isolated bony element found distal to the acromion after shoulder trauma should be interpreted as a fresh fracture if the patient reports isolated tenderness over the site, perhaps accompanied by crepitation. But if these circumscribed signs are absent, it should be assumed that the feature is an incidental finding based on an anatomic variant. If radiographs were ordered for unexplained shoulder pain not related to trauma, the radiologist should decide whether the shape and position of the accessory bony element are sufficient to narrow the subacromial space and cause an impingement injury with a partial or full tear of the supraspinatus tendon in the case of hyperextension. This question is most easily resolved by ultrasonography or MRI, depending on availability and examiner experience. • A 50-year-old woman complains of pain in the metatarsophalangeal joint of the right big toe after prolonged walking. She gives no history of trauma. A radiograph shows a relatively dense “bipartite” lateral sesamoid and mild hallux valgus deformity of the toe. Question: Is the lateral sesamoid a normal anatomic variant (duplication), does the bone exhibit necrotic fragmentation, or is the pain caused by metatarsophalangeal osteoarthritis that is not yet visible on radiographs? Clinical examination is not helpful in this case because both extreme flexion and hyperextension elicit pain throughout the metatarsophalangeal joint, and the pain is very poorly localized on palpation of the plantar side. Further evaluation by radionuclide bone scan is indicated (Fig. 7.440). Increased uptake in the lateral “bipartite” sesamoid would indicate necrotic fragmentation, necessitating surgical removal. Increased uptake in the subchondral portion of the bone would be more suggestive of osteoarthritis. • A 5-year-old child presents with nonspecific pain in the right knee. Radiographs show rarefaction and irregularity of the distal medial metaphyseal cortex. Differential diagnosis: inflammation, malignant tumor, or cortical irregularity? The region is completely normal to palpation and ultrasound scanning. The opposite knee has the same radiographic appearance. The finding can now be confidently interpreted as a transient cortical irregularity (normal variant), and there is no need for follow-ups (Fig. 7.45). It should be added, however, that highly typical radiographic findings in a bone do not always require a “confirmatory” view of the opposite side. Also, the absence of a corresponding finding on the opposite side does not preclude a normal variant, since many such variants occur on one side only. But if the area is tender to pressure and also shows slight swelling, the case warrants further investigation by bone scanning or modern sectional imaging techniques. Rules for Correctly Identifying Variants Accessory bone element: An accessory bone element arises from an isolated ossification center that is independent of the adjacent “established” bone, or it may result from a failure of fusion of a second ossification center at the margin of the established bone. In the last case generally a synchondrosis persists between the accessory element and the established bone. Painful regressive changes may develop in a synchondrosis that is exposed to adverse mechanical stresses (Table 1.1). The accessory bone element is entirely surrounded by cortical bone and does not “complete” the other bone (Figs. 2.205 and 2.151 b). The main differential diagnosis is a detached bone fragment, which is generally distinguished by irregular fracture margins and by the...
