Weightbearing Digital Tomosynthesis of Foot and Ankle Arthritis: Comparison With Radiography and Simulated Weightbearing CT in a Prospective Study.

OBJECTIVE: Foot and ankle arthritis is common and debilitating. Weightbearing radiography is the reference standard for evaluating alignment, but overlapping bones and hardware limit evaluation for osteoarthritic bony detail. The purpose of this study was to evaluate whether digital tomosynthesis (DTS) can yield reliable quantitative alignment values, as radiography does with its weightbearing capability, and good qualitative osteoarthritic detail, as CT does. SUBJECTS AND METHODS: Adults with foot or ankle arthritis referred for simulated weightbearing CT were recruited to undergo weightbearing radiography and DTS. Four readers independently evaluated radiographs and DTS images for foot and ankle alignment and severity of osteoarthritis in each joint. Two readers performed consensus readings of CT images. Agreement between modalities was assessed by intraclass correlation coefficient (ICC) and Cohen kappa statistics. RESULTS: Ninety-one ankles were analyzed. Most joints were significantly less obscured by overlapping bone when seen with DTS (11.2%) or CT (4.3%) compared with radiography (30.4%). For quantitative foot alignment measurements, DTS had good to excellent agreement with weightbearing radiography (ICC, 0.65-0.93), which performed significantly better than CT (ICC, 0.39-0.87). For qualitative osteoarthritic details of each joint, DTS had significantly better agreement with weightbearing radiography on joint space narrowing (κ = 0.38-0.67) than did CT (κ = 0.08-0.62). Weightbearing radiography and DTS had similar levels of agreement with CT on grading of osteophytes, subchondral cysts, and loose bodies. CONCLUSION: DTS is associated with less obscuration of joints than radiography and yields more reliable weightbearing quantitative foot and ankle alignment values than radiography does and more reliable osteoarthritic bony details than CT does.

Long-term radiographic follow-up of bisphosphonate-associated atypical femur fractures.

OBJECTIVE: To evaluate the appearance of bisphosphonate-related femur insufficiency fractures on long-term follow-up radiographic studies and to describe the rate of fracture line obscuration and cortical beak healing over time. MATERIALS AND METHODS: In this retrospective study, bisphosphonate-related femur fracture radiographs were reviewed by two radiologists for the presence of a fracture line, callus, and the characteristic cortical beak. Kaplan-Meier curves were used to analyze the time to first indication of healing. Femurs were also subdivided into those who underwent early versus late surgical fixation and those who underwent early versus late discontinuation of bisphosphonate. Clinical data including pain level and medication history were collected. RESULTS: Forty-seven femurs with a bisphosphonate-related femur fracture were identified in 28 women. Eighty-five percent took a bisphosphonate for greater than 5 years and 59 % for greater than 10 years. The median time to beak healing was 265 weeks and the median time to fracture line healing was 56 weeks in the 31 femurs with a baseline fracture. No statistically significant difference was identified between surgical fixation and conservative management. CONCLUSIONS: Bisphosphonate-related fractures demonstrate notably prolonged healing time on long-term follow-up.

Osteoarticular transplantation: recognizing expected postsurgical appearances and complications.

Despite technologic advances in prosthetic joint replacement, young patients who have lost a large volume of bone or soft tissue because of a tumor or traumatic injury may not be good candidates for prosthetic implants, which have limited longevity relative to that of biologic tissue grafts. In recent years, the use of biologic materials in orthopedic surgery has increased. Such materials, known as allografts, consist of cadaveric bone, cartilage, and other soft tissues that can be transplanted into a living patient. Alternatively, osteochondral autografts, or autologous grafts of the patient's own bone and/or cartilage, can be harvested from one body site and transplanted to another. Surgical procedures range from the local implantation of small osteochondral plugs to the replacement of entire joints with allografts. The size of the allograft used depends on the amount of bone and soft tissue needed. The use of allografts in patients with large-volume bone loss often preserves limb function, obviating amputation, which makes it an attractive option for treatment of young patients. Advantages of using allografts include the similarity of graft materials to native tissues and the decreased patient morbidity in the absence of an autograft donor site; disadvantages include slower biologic remodeling and graft incorporation than are typical with the use of autologous grafts. Potential complications of allograft tissue implantation include graft nonunion, collapse, and failure; infection; and secondary osteoarthritis. The article discusses the indications for and basic steps involved in each type of transplant procedure, normal pre- and postoperative imaging appearances, and imaging features that may be indicative of transplant complications.

Progressive retraction of a fractured os peroneum suggesting repetitive injury to the peroneus longus tendon.

The os peroneum is an accessory ossicle within the peroneus longus tendon. Prior reports have discussed fracture of the os peroneum with associated tears of the peroneus longus tendon. When the ossicle fractures, there can be varying degrees of retraction of the tendon, which can be diagnosed by malposition of the ossicle or the ossicle fragments. We report a case of a man with recurrent eversion ankle injuries with progressive retraction of a fractured os peroneum, implying injuries to the superior and inferior peroneal retinacula and the peroneus longus tendon.

Soft Tissue Sarcoma Response to Two Cycles of Neoadjuvant Chemotherapy: A Multireader Analysis of MRI Findings and Agreement with RECIST Criteria and Change in SUVmax.

RATIONALE AND OBJECTIVES: When soft tissue sarcomas are treated with neoadjuvant chemotherapy, the number of cycles of chemotherapy is usually dependent on the tumor's initial response. Popular methods to assess tumor response include Response Evaluation Criteria in Solid Tumors (RECIST) criteria, which rely solely on tumor size, and maximum standardized uptake value (SUVmax) reduction in positron emission tomography (PET), which requires an expensive and high radiation test. We hypothesized that contrast-enhanced magnetic resonance imaging (MRI) may offer a good alternative by providing additional information beyond tumor size. MATERIALS AND METHODS: Following IRB approval, a retrospective review identified patients with soft tissue sarcomas who underwent both PET and MRI before and after two cycles of neoadjuvant chemotherapy. Five readers independently examined the MRI exams for: changes in size, T2 or T1 signal, necrosis and degree of enhancement. Readers then made a subjective binary assessment of tumor response to therapy. Each reader repeated the anonymized randomized reading at least 2 weeks apart. 18 F-FDG PET exams were interpreted by a nuclear medicine specialist. The maximum standardized uptake values (SUVmax) for pre and post-chemotherapy exams were compared. Intra- and inter-reader agreement was assessed using Cohen's kappa and Light's kappa, respectively. . RESULTS: Twenty cases were selected for this multireader study, of which 9 (45%) were responders and 11 were nonresponders by SUVmax. Using all MRI criteria, 43% were classified as responders based on MRI and 1.5% were classified as responders by RECIST criteria. Using PET as the reference, the sensitivity and the specificity of the MRI diagnosis for response using all findings were 50% and 63%, respectively. There was fair to moderate intrareader (kappa = 0.37) and inter-reader (kappa = 0.48) agreement for the MRI diagnosis of response. None of the individual MRI signal characteristics were significantly different between the PET responders and nonresponders. Additionally, no MRI findings were significantly different between those with and without good clinical responses. CONCLUSION: By our assessment, there is a poor correlation between tumor response by RECIST criteria and PET SUVmax. In addition, varying MR features did not help in diagnosing tumor response. Imaging of tumor response remains a challenging area that requires further research.

Asymmetric bone mineral density in the bilateral femoral necks due to gluteal implants: a case report.

Interpreting asymmetric bone mineral density in the bilateral hips on dual energy x-ray absorptiometry requires investigation into the potential causes, both real and artifactual. Silicone gluteal implants have been reported to cause abnormally elevated bone mineral density. We report a case of abnormally low bone mineral density in a patient with bilateral gluteal implants. This is likely due to patient positioning and inability of the computer to identify the superior margin of the proximal femur and the femoral neck.

Epidemiology and imaging appearance of the normal Bi-/multipartite hallux sesamoid bone.

BACKGROUND: Turf toe is a hyperextension injury of the hallux metatarsophalangeal joint that can be difficult to diagnose on physical examination and imaging. Diastasis of the bi- or multipartite sesamoid of the hallux has been implicated as 1 potential radiographic finding of turf toe injury, and when present may require operative management. However, the normal interval for the bi-/multipartite sesamoid has not yet been established. METHODS: A total of 671 foot radiograph series were reviewed in effort to quantify the dominant interval of the bi-/multipartite sesamoid bone with respect to potential influencing factors including right versus left foot, medial and/or lateral sesamoid involvement, patient age and gender, and weight versus non-weight-bearing radiograph technique. RESULTS: The prevalence of a bi-/multipartite hallux sesamoid was 14.3% in our population. The dominant sesamoid interval ranged from 0-2 mm, with an average of 0.79 mm. CONCLUSION: We conclude that sesamoid diastasis should be considered, in the appropriate clinical setting, when the sesamoid interval is greater than 2 mm on a routine AP radiograph of the foot. LEVEL OF EVIDENCE: Level III, comparative study.

Magnetic resonance imaging safety in cardiothoracic imaging.

Patient safety is a priority for patients undergoing magnetic resonance imaging (MRI). This article reviews MRI safety issues related to devices, pharmacologic stress agents, contrast agents, anesthesia, and external equipment, focusing on cardiothoracic MRI.

Craniocervical hyperpneumatization with concurrent pneumorrhachis, pneumomediastinum, and subcutaneous emphysema in a weightlifter.

BACKGROUND CONTEXT: Acquired hyperpneumatization of the skull base and upper cervical vertebrae is extremely rare and is thought to occur in patients who habitually perform the Valsalva maneuver or engage in repetitive positive pressure activities such as scuba diving or free diving. Craniocervical hyperpneumatization has been reported to cause intracranial and extracranial pneumatoceles but is not generally considered as a cause of pneumorrhachis (air in the spinal canal). Pneumorrhachis is relatively rare, and usually occurs in a localized form, either in the cervical spine secondary to skull base fractures or in the thoracic spine secondary to pneumomediastinum or pneumothorax. Here, we report a case of extensive pneumorrhachis extending from the skull base to the thoracolumbar junction in association with marked axio-atlanto-occipital hyperpneumatization and pneumomediastinum. This unique constellation of findings likely resulted from complications of the Valsalva maneuver during strenuous exercise. PURPOSE: To present a unique case of axio-atlanto-occipital hyperpneumatization with concurrent marked cervicothoracic pneumorrhachis, subcutaneous emphysema, and pneumomediastinum and to provide a review of the relevant literature, pathophysiology, and treatment strategies related to hyperpneumatization and pneumorrhachis. STUDY DESIGN/SETTING: A unique case report from an urban medical center. PATIENT SAMPLE: A single case. OUTCOME MEASURES: Imaging findings and clinical history. METHODS: Imaging data from a picture archiving and communication system and clinical data from an electronic medical record system were analyzed. RESULTS: A 58-year-old previously healthy man presented with 3 to 4 weeks of neck pain, shoulder pain, and intermittent hand and finger numbness that developed after weightlifting. On physical examination, he had mild hyperreflexia and decreased pinprick sensation within the T5-T8 dermatomes. Initial radiographic and computed tomography (CT) studies demonstrated extensive craniocervical hyperpneumatization involving the occipital bone, clivus, and C1 and C2 vertebral bodies. There was also pneumorrhachis extending throughout the entire cervical and thoracic spine, which caused moderate dural compression. Pneumomediastinum and subcutaneous emphysema were present. Maxillofacial CT showed dehiscent bone involving the dens, atlas, and occipital bone, with adjacent soft-tissue gas and pneumorrhachis. He was managed conservatively and advised to stop performing the Valsalva maneuver during weightlifting. His symptoms resolved, and follow-up imaging showed complete resolution of pneumorrhachis and partial reversal of hyperpneumatization. CONCLUSIONS: Craniocervical hyperpneumatization is a rare complication of the Valsalva maneuver. Most reported cases have involved only the skull base, or the skull base and C1, and many have been further complicated by microfractures leading to pneumocephalus or extracranial pneumatoceles. We present a unique case of extensive craniocervical hyperpneumatization that extended to the level of C2 and was complicated by microfractures causing severe pneumorrhachis. Concurrent pneumomediastinum in this case may have been an independent complication of the Valsalva maneuver, which could have contributed to pneumorrhachis. Alternatively, pneumomediastinum may have been caused by migration of gas through the neural foramen from the epidural space, driven by positive pressure generated by the one-way valve effect of the Eustachian tube during periods of exertion.