Soft-tissue masses: optimal imaging protocol and reporting.

OBJECTIVE: Soft-tissue masses derive from a wide spectrum of tissues, and it may be difficult to differentiate nonneoplastic from neoplastic as well as benign from malignant lesions, to say nothing of making a single histologic diagnosis on the basis of imaging. The purpose of this article is to discuss optimal imaging protocols and reporting of soft-tissue masses. CONCLUSION: The radiologist should be prepared, if at all possible, to knowledgably examine the patient, optimize an imaging protocol, and differentiate among lesions. Specific features of an MRI examination must be discussed in each report to completely evaluate the mass and perform efficacious biopsy, staging, and eventual treatment of the lesion. Careful and systematic reporting of the examinations should avoid the devastating consequences of either overlooking a sarcoma or overtreating a benign lesion.

Low-grade cartilage tumors: diagnosis and treatment.

As a result of reading this article, physicians should be able to: 1. List the features that are useful in differentiating a low-grade chondrosarcoma from an enchondroma. 2. Describe the treatment principles of low-grade cartilage tumors based on the anatomic location and stage of the tumor. 3. Discuss the characteristics of a local recurrence after initial treatment and the general consequences.

Imaging of cartilage in the athlete.

Since the development of radiography, we have been able to visualize the osseous alterations related to arthritis. These include productive changes, such as osteophyte formation, sclerosis, and buttressing, as well as erosive changes and subchondral cyst formation. However, because cartilage is radiolucent, it is not directly visible by either radiography or computed tomography. With careful attention to technique, both hyaline and fibrocartilage can be visualized by magnetic resonance imaging.

Musculoskeletal oncologic imaging.

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.

Magnetic resonance imaging of peripheral nerve sheath tumors. Assessment by numerical visual fuzzy cluster analysis.

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 tumors of bone.

Giant cell tumor is a lesion that usually presents with a radiographically characteristic appearance in a predictable location and patient population. It has a few rare presentations such as pulmonary metastases and multifocal lesions. Prognosis of ultimate tumor behavior is dependent on surgical staging (which requires careful radiographic analysis to detect cortical breakthrough and joint involvement) and type of treatment. The recurrence rate is relatively high with simple curettage but decreases with adjuvant treatment at the tumor site. Optimal therapy for the more aggressive lesions is wide resection, but compromise is frequently required when such a resection would sacrifice joint function because of the subarticular location of the giant cell tumor. Radiation therapy is reserved for surgically inaccessible or otherwise inoperable lesions because of a relatively poor radiosensitivity and concerns about induction of high grade sarcomas. Radiographic follow-up evaluation for recurrence is recommended for approximately 5 years but may be difficult to interpret in individual patients because of an overlap in the appearance of healing and recurrence.

Subtle injuries of the Lisfranc joint.

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 imaging of vascular anatomy before vascularized fibular grafting.

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.

Techniques for estimating allometric equations.

Morphologists have long been aware that differential size relationships of variables can be fo great value when studying shape. Allometric patterns have been the basis of many interpretations of adaptations, biomechanisms, and taxonomies. It is of importance that the parameters of the allometric equation be as accurate estimates as possible since they are so commonly used in such interpretations. Since the error term may come into the allometric relation either exponentially or additively, there are at least two methods of estimating the parameters of the allometric equation. That most commonly used assumes exponentiality of the error term, and operates by forming a linear function by a logarithmic transformation and then solving by the method of ordinary least squares. On the other hand, if the rrror term comes into the equation in an additive way, a nonlinear method may be used, searching the parameter space for those parameters which minimize the sum of squared residuals. Study of data on body weight and metabolism in birds explores the issues involved in discriminating between the two models by working through a specific example and shows that these two methods of estimation can yield highly different results. Not only minimizing the sum of squared residuals, but also the distribution and randomness of the residuals must be considered in determing which model more precisely estimates the parameters. In general there is no a priori way to tell which model will be best. Given the importance often attached to the parameter estimates, it may be well worth considerable effort to find which method of solution is appropriate for a given set of data.

Justification for decreasing the number of views taken in radiologic follow-up of Casper plate cervical spine hardware.

RATIONALE AND OBJECTIVES: We tested the null hypothesis that there would be no difference between the diagnostic yield of the lateral radiograph alone and the yield of the lateral and anteroposterior views combined when assessing patients after placement of an anterior cervical appliance. METHODS: We evaluated 630 radiographic examinations obtained from 117 consecutive patients who had anterior cervical plating. For each examination, we looked at the lateral radiograph first and then at the anteroposterior radiography to determine whether there would be any additional information on the anteroposterior film. RESULTS: Of 501 examinations in which the lateral and anteroposterior views were available, we found that the anteroposterior view added information in 18. In eight of the 18, the added information consisted only of clinically insignificant tilting of the plate. Significant findings were seen in 209 examinations in the lateral view and in 219 examinations with the lateral and anteroposterior views combined. This was not significantly different. CONCLUSION: The anteroposterior view rarely adds significant information. It probably should be obtained early postoperatively to check for tilting of the plate but after that only for specific indications. This will save money and reduce the patient's exposure to radiation.

Career advancement of men and women in academic radiology: is the playing field level?

RATIONALE AND OBJECTIVES: The authors' purposes were to determine if there are gender differences in the speed of promotion and/or academic productivity in academic radiology and if this situation had changed since a previous study was performed in 1987. MATERIALS AND METHODS: Surveys were distributed to faculty members of academic radiology departments in May 1997. A total of 707 surveys were analyzed according to gender for time at rank for assistant and associate professor levels, in relation to publication rate, grant funding rate, and distribution of professional time. RESULTS: There was no difference between genders in the time at assistant professor rank. Among all current professors, women had been associate professors longer than men, but there was no difference between genders for those who had been in academic radiology for less than 15 years. There was no gender difference at any rank in the rate of publishing original articles. There was no difference in funding rates, although men had more total grant support. Male associate professors reported spending more time in administration and slightly more time in total hours at work than did their female colleagues, and male professors spent slightly more time teaching residents. Otherwise, there is no difference in how men and women at any rank spend their professional time. There are, however, lower percentages of women in tenured positions and in the uppermost levels of departmental administration. CONCLUSION: The time at rank for men and women and their rate of publication appear to have equalized. Women still are underrepresented at the uppermost levels of departmental administration, however, and are less likely than men to hold tenured positions.

The road to success: factors affecting the speed of promotion of academic radiologists.

RATIONALE AND OBJECTIVES: The authors' purpose was to determine the factors influencing the speed of promotion of academic radiologists. MATERIALS AND METHODS: Three hundred forty-three surveys from faculty members of academic radiology departments with continuous academic careers were analyzed for time in rank at assistant and associate professor levels in relation to publication rate, grant funding rate, and distribution of professional time. Individuals promoted faster than the median time (6 years for assistant professors, 5 years for associate professors) were considered "fast track" and were compared with the remainder of the group. RESULTS: At the assistant professor level, fast track individuals had significantly higher rates of total publications and original articles than did others. At the level of associate professor, fast track individuals had significantly faster rates of publication of original articles, but no significant difference existed in total publication rate. No significant difference was found in the rate of founding of fast track individuals and others. Those with funding were not more likely to be on a fast track than those without funding. Fast track individuals spent significantly more time in administration at the assistant professor level than did other faculty, but no other significant differences were discovered in time distribution at the assistant or associate professor level. CONCLUSIONS: The rate of publishing original articles at the assistant and associate professor levels and the rate of overall publication at the assistant professor level were the most important parameters in predicting speed of promotion.

Digital wrist arthrography: precision in determining the site of radiocarpal-midcarpal communication.

Wrist arthrography is used for precise determination of posttraumatic interosseous ligament tears. Digital subtraction arthrography adds to the precision in diagnosis of the site of radiocarpal-midcarpal communication. Using the technique for digital subtraction wrist arthrography outlined in this paper, the classic scapho-lunate and lunate-triquetral perforations were delineated. Scaphotrapezium and triquetral-hamate interosseous ligament perforations were also delineated. The added diagnostic precision of digital subtraction at the first injection was useful in planning the correct surgical procedure.