Biomedical subjects
Publications and source records attributed to R H Daffner.
The diagnosis of acute tendon ruptures of the extensor mechanism of the knee or the Achilles tendon of the ankle may usually be made by clinical means. Massive soft tissue swelling accompanying these injuries often obscures the findings, however. Magnetic resonance imaging (MRI) can rapidly demonstrate these tendon ruptures. Examples of the use of MRI for quadriceps tendon, and Achilles tendon rupture are presented.
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Vertebral fractures, like fractures in the peripheral skeleton, occur in predictable and reproducible patterns that are related to the kind of force applied to the affected bone. The same force applied to the cervical, thoracic, or lumbar column will result in injuries which appear quite similar. A review of 621 injuries to the vertebral column revealed that there are basically four mechanisms of injury: flexion, extension, shearing, and torque (rotation). These injuries may occur by themselves or in combination with one another. The severity and extent of damage produced by any mechanism is dependent upon the incident force, the position of the patient at the time of injury, and the velocity of the patient. Thus, there is a pattern of recognizable signs which span the spectrum from mild soft tissue damage to severe skeletal and ligamentous disruption. These patterns are termed the "fingerprints" of the injury, and this presentation illustrates the four basic types of vertebral injury producing those "fingerprints."
Magnetic resonance imaging (MRI) of the breast was performed in 10 volunteers and 102 women with suspected breast disease, using a 0.35-T superconducting magnet. All patients had prior x-ray mammography. MRI was superior to mammography in differentiating solid from cystic lesions and equivalent to mammography in providing information regarding different parenchymal patterns. Of 21 surgically proven carcinomas of the breast, MRI correctly identified 18 and mammography identified 19. The major disadvantage of MRI is its inability to show calcifications, benign or malignant. Future studies will be needed to show the relative values of sonography and MRI in detecting small cysts. In addition, MRI in future should be able to demonstrate small, noncalcified masses in mammographically dense, fibrocystic breasts.
Magnetic resonance imaging (MRI) at 0.35 T with a superconductive magnet was performed on 80 patients with known or suspected malignant disease of the bone marrow. The group comprised 50 patients with known primary malignancy and 30 with known multiple myeloma. The MRI scan was correlated with plain films and radionuclide bone scans. In 40 patients with suspected metastatic disease, areas of decreased signal intensity on T1-weighted spin-echo images were observed. Ten patients had no MRI evidence of metastasis, and the abnormalities suspected on bone scanning were shown to be due to other causes. All the myeloma patients had abnormalities demonstrated by MRI. This was significant, since most had normal bone scans. All diagnoses were confirmed by needle biopsy. MRI was shown to be a sensitive method of detecting areas of malignancy within the bone marrow toward which biopsy could be directed.
Negative ulnar variance is a condition in which the ulna is relatively shorter than the radius at the carpus. It was found in 21% of 203 normal wrists. We have observed an increased incidence (49%) of this anomaly in patients with carpal ligamentous instabilities (dorsiflexion instability, palmar flexion instability, scapholunate dissociation with rotary luxation of the scaphoid, and lunate and perilunate dislocations). While the reasons for this association have yet to be adequately delineated, the presence of a negative ulnar variant may serve as an impartial clue to the presence of ligamentous instability. Many carpal instabilities present with subtle radiographic findings requiring careful evaluation of radiographs. Patients with negative ulnar variance and histories suggestive of ligamentous instability should undergo careful radiologic evaluation to assure early diagnosis of carpal disruption.
Four patients who had received chymopapain injections for treatment of herniated lumbar disks were evaluated by computed tomography (CT) because of persistent low back pain and suspicion of infection. Irregularity of the vertebral end-plate and a mottled appearance of the vertebral bodies suggested the diagnosis of disk-space infection in all four cases. CT-guided biopsy of the disk space was performed in each case, and bacterial cultures demonstrated staphylococcal infections, which were treated accordingly. Diskitis secondary to chymopapain injection is rare because of the precautions that are usually taken. No antibiotics are used routinely with such injections, although systemic antibiotics have been used in diabetics for prophylaxis.
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Radiolucent horizontal striations of the anterior cortex of the tibia were seen in 10 athletes who were evaluated for "shin-splints." There were seven basketball players, two professional dancers, and one hurdler. Each patient's history included vigorous leaping in performance of athletic feats. All the lesions were similar in location and appearance and were accompanied by thickening of the anterior tibial cortex. These striations are considered stress fractures and were not observed in a group of runners who were evaluated for shin-splints.
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A prospective study was performed to evaluate the efficacy of including oblique radiographs as part of a lumbar vertebral column examination. Five hundred patients in the second through ninth decades of life were evaluated. Of those, 12% had an abnormality detected on the 45 degree oblique view that was not apparent on the frontal or lateral radiographs. Those abnormalities included degenerative changes of apophyseal joints (6%), spondylolysis (4%), osteoid osteoma, anomalous apophyseal joint, and abnormal pars interarticularis (2%). These results are compared with those of other investigators and the reasons for variance are discussed.
Congenital clefts and aplasias of the atlas vertebra, while rare, are often first encountered in the emergency room setting. Thirty-six patients with atlas malformations and 10 with Jefferson fractures were encountered. Sixteen of the patients with congenital malformations showed bilateral atlantoaxial lateral offset, a finding generally considered to be the result of fracture. The diagnosis of these abnormalities is readily made from plain films by noting their characteristic features. Anomalies produce lateral offset of 1-2 mm. Jefferson fractures produce a greater offset (over 3 mm).
Traditional plain film evaluation of facial fractures includes a lateral view of the face. This projection is often not exploited to its full potential because the many overlapping shadows are perceived to detract from its usefulness. To assess the value of this view, the authors reviewed the later al facial films of 50 patients with a variety of fractures including 25 orbital blow-out fractures, 27 zygomaticomaxillary complex fractures, and 17 maxillary (including Le Fort) fractures. Three observations were encountered: orbital floor displacement in 60% of orbital fractures; malar strut displacement in 41% of zygomaticomaxillary complex fractures; and maxillary wall displacement in 76% of maxillary fractures. The presence of any of these structural displacements, either alone or in combination, provides further direct evidence of skeletal disruption and should serve to augment the findings observed on frontal views.
The common denominator of any roentgenographic study is the ability of the radiologist to interpret the image on the film. We are aware that the makeup of that image is a composite of the shadows of all the structures through which the roentgen beam passes. Less well appreciated, however, is a variety of illusory phenomena which results from overlapping shadows, differences in background illumination, and subjective contour formation. The result is a variety of false images which exists in the "mind's eye" only and may be misinterpreted as significant pathologic abnormalities. The three most common causes of illusory phenomena are Mach bands, background density effect, and subjective contours. These are all related and are derived from the process of lateral inhibition. It is important for radiologists to recognize these phenomena in order to avoid their pitfalls. This paper will describe these phenomena and will review previous work on perception.
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This report describes the anatomy, pathophysiology, clinical, and radiographic findings, and treatment of the synovial plicae of the knee joint. The suprapatellar plica is a synovial fold present in the suprapatellar pouch of the knee joint in approximately 20% of the population. This fold may become symptomatic after injury and cause symptoms similar to other common internal derangements of the knee. Double contrast arthrography of the knee can be used to identify the presence of plicae. Although arthrography can identify the presence of a plica, its clinical significance requires close correlation with symptoms and an accurate clinical examination.
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