Biomedical subjects
Publications and source records attributed to B J Manaster.
A cost efficient algorithm is presented for workup of musculoskeletal tumors. This is given within the framework of requirements for surgical staging. Considerations regarding both percutaneous and open biopsy are outlined. The advantages as well as limitations of MR imaging are stressed.
Triple-injection wrist arthrography has been demonstrated to increase the likelihood that all the ligamentous perforations in an injured wrist will be diagnosed. However, compared with imaging after single injection of contrast material into the radiocarpal joint, triple-injection arthrography not only increases patient expense but also significantly increases the time required of both patients and arthrographers to obtain the diagnosis. With the goal of decreasing the number of triple injections, the author reviewed 50 consecutive triple-injection wrist arthrograms. Using a technique based on high-volume injection of contrast material to achieve complete distention of the joint, the author achieved a false-negative rate for demonstration of complete perforations with radiocarpal injection alone of only 2% (10% if partial perforations were included). In none of these cases was patient treatment altered by the additional information provided by the second and third injections. This false-negative rate is significantly lower than that reported previously and raises the question of whether there are circumstances in which the easier and less time-consuming single radiocarpal injection might be appropriate.
Although soft-tissue calcification is common in collagen vascular disease, paraspinal calcification in the cervical spine has not been described before. We studied five women with large, lobulated, predominantly homogeneous calcific masses centered on synovial articulations in the neck. Changes consisting of either osteolysis or erosions were evident. All patients had radiculopathy, focal pain, or stiffness. In two patients, the presence of hydroxyapatite crystals was confirmed on biopsy. Symptomatic cervical paraspinal calcifications in patients with collagen vascular disease cause large soft-tissue masses that mimic tumoral calcinosis.
The knee is a complex joint capable of six types of motion, stabilized by four major ligaments and a capsule, and prone to soft tissue injury in our active society. Because of the complexity of motion and combination of ligamentous restraint, clinical evaluation is often difficult, particularly in the setting of an acute injury where pain and presence of an effusion limit the physical examination. Plain radiography is occasionally helpful in evaluation of the initial injury and quite useful in follow-up evaluation of ligament reconstructions and repairs. Magnetic resonance imaging (MRI) has become increasingly important in evaluation of both knee injury and subsequent reconstructions and repairs. This article will review knee anatomy, touch on important elements of the history and physical examination, and discuss plain film and MRI evaluation of both knee injury and reconstruction/repair for each individual ligament.
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A retrospective, nonblinded review of ten nerve sheath tumors (four malignant) selected for pathologic proof and complete magnetic resonance (MR) evaluation was performed to assess the primary tumor location, signal pattern, and extent of reactive zone. A modification of visual fuzzy cluster analysis (VFCA) that emphasized the number of visual fuzzy clusters in each mass was developed to assess the neural tumors. The MR findings were correlated with the findings at surgery and histopathology. There were six men and four women, aged 19 to 62 years (mean, 43). Nine tumors involved the lower extremity. In all tumors, MRI correctly identified the nerve trunk of origin. Tumor dimensions were generally overestimated by MRI. Three internal signal patterns were observed: homogeneous (1/1 benign), finitely inhomogeneous (5/5 benign), and hectically inhomogeneous (4/4 malignant). The number of visual fuzzy clusters (VFCRs) for each sequence did not allow reliable separation of benign and malignant entities, but when considered in aggregate, benign and malignant lesions segregated in different clusters. This implies that the likelihood of malignancy increases as the number of MR-identifiable tissue types per lesion increase. Three types of reaction (edema) were observed best on long repetition time/echo time (TR/TE) sequences, confined to immediate peritumoral region, intracompartmental, and extracompartmental. The first two patterns correlated well with clinicopathologic findings; however, the third pattern did not. Separation of indolent (benign) cellular masses from aggressive (malignant) ones by MR characteristics is difficult but VFCA shows promise for aiding this differentiation and deserves further investigation in larger study populations.
Giant cell tumor (GCT) is a relatively common primary bone tumor that typically develops in young adults between the ages of 20 and 40 years. Our archives contain 1,183 cases of histologically proved and radiographically correlated GCTs, collected in consultation over 40 years. From this large series, we identified 243 lesions (21% of GCTs) arising in the upper extremity distal to the scapula. This report demonstrates the spectrum of radiologic findings of GCT of the upper extremity, augmented where appropriate by accompanying pathologic material.
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Free vascularized fibular grafting, in which the peroneal artery is harvested with the fibula, is a popular procedure for filling osseous defects and for treatment of femoral head avascular necrosis. Preoperative vascular imaging is required in all patients to detect the origin of the peroneal artery, to measure the length available for the vascular pedicle, and to evaluate for the normal continuation of the three major vessels of the lower leg. Magnetic resonance imaging of the lower leg with use of gradient-recalled acquisition in a steady, state was performed in 35 patients to evaluate vascular anatomy. Surgical correlation was available in 91% of cases, and in these 100% accuracy was demonstrated. Postoperative radiographs showed that grafts placed for osseous defects in the upper extremity were incorporated and hypertrophied extremely quickly, while those placed in the major weight-bearing bones of the lower extremity were much more prone to complications including delayed union, fracture, and infection. Vascularized grafts placed in the femoral head and neck for avascular necrosis incorporate only in the cephalic portion and should be watched carefully for signs of early and progressive femoral head collapse.
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In fifteen patients, a subtle injury of the Lisfranc joint (tarsometatarsal articulation) was found. The lesion was defined as a diastasis of two to five millimeters between the bases of the first and second metatarsals, as seen on anteroposterior radiographs. There often was a long delay between injury and diagnosis. Eight patients were treated with a below-the-knee cast only, three had treatment with a cast and then tarsometatarsal arthrodesis, two had no initial treatment but later had arthrodesis, and two had open reduction and internal fixation. The duration of follow-up ranged from two to thirteen years after the diagnosis. There was no correlation between the severity of the diastasis and the patient's functional result. Marked disability and pain persisted in seven patients, and six of them had flattening of the longitudinal arch. Maintenance of the longitudinal arch usually was associated with a better functional outcome. When a patient has a subtle injury of the Lisfranc joint, weight-bearing lateral radiographs of both feet are needed to identify flattening of the longitudinal arch. Such radiographs should be made routinely in the evaluation of all injuries of the foot that may involve the Lisfranc joint.
Magnetic resonance images of the leg were made preoperatively to show the vascular anatomy in twenty-nine patients (thirty-five legs) who were between the ages of fourteen and forty-one years and in whom we planned to use the fibula as a vascular graft. The fibula was harvested as a graft in thirty-two legs, and this allowed us to compare the images with the anatomical findings at operation. In these thirty-two legs, the branching pattern, the measured distance to the bifurcation of the peroneal artery, and all vascular anomalies in the area were accurately detected. No graft was taken from the other three legs. We recommend that imaging of the vascular anatomy of the leg be done before using the fibula as a vascular graft in order to detect the precise point of origin of the peroneal artery from the posterior tibial artery, to estimate the length of the vascular pedicle, and to evaluate the role of the three major vessels in supplying blood to the leg. All these aims can be accomplished with the aid of angiography, but we have found that gradient-recalled acquisition in the steady state (GRASS) magnetic-resonance imaging is more cost-effective and is associated with less morbidity. It is not adequate for older patients who have arterial stenosis or atherosclerosis or for patients who have some other underlying vascular disease. Metallic hardware may cause artefacts that obscure the vascular anatomy.
A technique adding digital subtraction to otherwise standard wrist arthrography allows more precise determination of the site of radiocarpal-midcarpal communications. Since arthrographic results often do not correlate with clinical findings, we became interested in correlating these various modalities. The precision of our arthrographic interpretation makes these correlations meaningful. In 72 consecutive patients who had digital subtraction wrist arthrograms, both clinical sites of pain and plain film abnormalities were correlated with arthrographic findings. The results indicate that those patients with ulnar-sided pain more commonly have perforations in that region (88%). Radial-sided pain is a poor indicator of a radial site of perforation. Scapholunate dissociation does not correlate highly with scapholunate perforation (26%).
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The efficacy of "weighted" films in diagnosing grade 3 acromioclavicular (AC) sprains not evident on plain (unweighted) films was evaluated. Eighty-three pairs of radiographs, taken with and without weights, of patients with suspected AC injury were studied. The films were read in a randomized and blinded manner by a staff radiologist. Criteria for classifying AC injuries were: grade 1, less than 3 mm (or less than 50%) difference between the AC widths with a normal coracoclavicular (CC) distance; grade 2, greater than or equal to 3 mm (or greater than or equal to 50%) difference between the AC widths with a normal CC distance; and grade 3, greater than or equal to 5 mm (or greater than or equal to 50%) difference in CC distance. In only three cases (4%) did weights cause the injured CC distance to increase and thereby unmask a grade 3 injury not evident on plain films. Further evidence that weights may not reliably elucidate the degree of AC joint injury is suggested by the fact that in several cases the weights actually caused the injured and uninjured CC distance to decrease. We conclude that the use of weighted radiographs lacks efficacy in unmasking grade 3 AC sprains on radiograph and we recommend that routine use of this technique be abandoned.
New concepts in knee ligament reconstruction have recently emerged, significantly improving the success of surgical reconstruction of anterior and posterior cruciate ligaments, using high-strength bone-patellar tendon-bone grafts, as well as medial and lateral collateral soft-tissue ligament reconstructions. We reviewed plain radiographs of 50 patients with a total of 72 ligament reconstructions to determine radiographic signs of complications. A major early complication relates to reconstructed ligament positioning. Isometric positioning of the reconstruction is important for all ligaments, but it is most crucial for the femoral portion of the anterior cruciate ligament. Three cases of nonisometric ligament positioning were identified, two anterior cruciate ligaments and one medial collateral ligament. Another early complication is graft fracture, identified in two cases of anterior cruciate ligament reconstruction. Hardware failure did not occur in this series. Late complications include motion of the graft (none in this series) and patellar fracture (one case in this series). Effusions resolved by 4 weeks in 92% of the cases. However, prolonged effusions are usually sterile and should not be mistakenly diagnosed as representing a septic joint if they are an isolated finding. Nonunion of the graft within its osseous tunnel is unusual. Union occurred in 79% of cases by 6 weeks and in 95% of cases by 5 months. Osseous tunnel sclerosis alone is not considered a complication. We conclude that postoperative plain film radiography is important for assessment of graft and hardware position as well as for the detection of early and late surgical complications.
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