Imaging of Melorheostosis: Emphasis on MR Imaging Findings

PURPOSE: To evaluate the usefulness of various radiographic imaging modalities in the diagnosis and characterization of melorheostosis. MATERIALS AND METHODS: We retrospectively evaluated the plain film (n=8), computed tomographic (CT) imaging (n=5) and magnetic resonance (MR) imaging (n=5) findings of eight patients with melorheostosis diagnosed by bone biopsy (n=4) and characteristic radiographic findings (n=8). MR images were obtained with a 1.5-T scanner focused on the region of maximal radiographic abnormality. Pulse sequences include T1-weighted SE, T2-weighted fast SE (n=5) and postcontrast imaging (n=4). In order to define subtle enhancement of the lesions, subtraction MR images were obtained in one case. Imaging findings were analyzed with particular emphasis on the distribution of lesions along the sclerotome, differential radiographic findings between diaphyseal and metaepiphyseal lesions of the long bones, as seen on plain radiographs, and the density and signal characteristics of hyperostotic, lesions, as seen on CT and MR images. RESULTS: Characteristic distribution along the sclerotome was identified in five of eight cases mainly along C6 and 7 (n=2) and L3, 4 and 5 (n=3) sclerotomes. In diaphyseal melorherostosis (8/8), a characteristic finding, i.e., a wax flowing down from the candle, was identified on plain radiographs. In all three patients with metaepiphyseal melorheostosis (3/8), multiple round or oval hyperostotic lesions were seen in the epiphysis and metaphysis of the long bones. On CT, the marrow cavity was partly obliterated by hyperostotic lesions in all five patients with endosteal hyperostosis. Among these, central ground glass opacity with a sclerotic rim was seen in three patients. Periosteal hyperostosis was seen in two of five cases, being visualized as irregular excrescences in the periosteal region and surrounding soft tissue. Individual hyperostosis was visualized as hypointense on T1-weighted images and as a hyperintense center with a surrounding hypointense rim on T2-weighted images (5/5). On postcontrast images, central enhancement was noted in all four cases. In one of these, in which the degree of central enhancement was subtle, subtraction images (postcontrast SE- precontrast SE) also revealed a central signal increment. Central enhancement corresponded to the hyperintense center seen on T2-weighted images (4/4) and the ground-glass opacity seen on CT (2/2). CONCLUSION: Radiographic imaging plays a crucial role in the diagnosis of melorheostosis. The future role of gadolinium-enhanced MR imaging in the characterization of the lesion may be important though further evaluation and pathologic correlation is required.

Radiological Findings of Bizarre Parosteal Osteochondromatous Proliferation

PURPOSE: To analyse the radiological findings of bizarre parosteal osteochondromatous proliferation (BPOP), a rare benign tumorous lesion with a high frequency of recurrence which frequently occurs around the short tubular bones of the hands and feet. MATERIALS AND METHODS: Between 1984 and 1998, 19 cases of BPOP were pathologically Proven, and in is of these, six men and nine women aged between 17 and 69(mean, 41) years, plain radiographs were available for analysis. We examined the location and size of lesions, and their relationship to adjacent bone. RESULTS: In all cases, trabecular bone formations were present. There were not separable from adjacent bones, which in all cases appeared normal. In nine of 15 cases margins were sharp, and in the remaining six they were irregular. Lesions were located around a phalanx of the hand (n=5), a metatarsal bone (n=3), a long bone (n=3), a phalanx of the foot (n=2), a metacarpal bone (n=1), and a metatarsophalangeal joint (n=1). Their average size was 2.5 x1.9cm, and in three of is cases the tumor recurred. CONCLUSIONS: BPOP showed a well-marginated mass of heterotopic mineral arising around short tubular bones. These findings were useful for diagnosis and differential diagnosis.

Radiologic Findings in Cases Involving Complications Arising from Total Knee Arthroplasty

Total knee arthroplasty(TKA) has been used for the treatment of knee joint pain, deformity, and instability caused by osteoarthritis, rheumatoid arthritis, or tuberculous arthritis, and by virtue of good results and rapid development, the procedure has been increasingly employed. With the development of total knee prosthesis, complications have also increased, however, and due to complications occurring up to six years after surgery, fusion occurs in about 2% of all replaced knees. The most common complication of TKA is loosening, followed by infection. Others are thrombosis, subluxation, dislocation and fracture, and complications may be divided into four groups: biologic, technical, specific to type of components, and associated with certain diagnosis. Where these complications occur, a patient must undergo a second procedure, but the success rate is lower than for the initial procedure. Exact etiological evaluation important clinically and radiologically. We illustrate the etiologies and radiologic characteristics of TKA complications according to classification.

Peritumoral Bone Marrow Edema in Benign Giant Cell Tumor

PURPOSE: To evaluate the frequency of peritumoral bone marrow(BM) edema accompanying benign giant celltumor(GCT) of the appendicular bone by magnetic resonance(MR) imaging and to correlate MRI findings with those ofplain radiography and bone scintigraphy. MATERIALS AND METHODS: Eighteen cases of pathologically proven benignGCT of the appendicular bone were retrospectively analyzed using MR images, plain radiographs and bonescintigrams. A plain radiograph was available in 15 cases, and a scintigram in six. Marrow edema was defined asperitumoral signal changes which were of homogeneous intermediate or low signal intensity(SI) on T1WI and high SIon T2WI, relative to the SI of normal BM, and homogeneous enhancement on Gd-DTPA-enhanced T1WI. The transitionzone, sclerotic margin and aggressiveness of the lesion were assessed on the basis of plain radiographs. BM edemaseen on MR images was correlated with plain radiographic and scintigraphic findings. RESULTS: 1. Peritumoral BMedema was seen on MR images in 10 of 18 cases (55.5%). 2. In 8 of 15 cases for which plain radiographs wereavailable, MR imaging revealed BM edema. In six of these eight, transition zone was wide, while in two it wasnarrow. Six of seven patients without marrow edema showed a wide transition zone, and in one this was narrow.There was significant correlation between BM edema shown by MR imaging and the transition zone seen on plainradiographs (x2, p<0.05). But The aggressiveness shown by plain radiographs correlated only marginally, while thepresence of sclerotic rim did not correlate. 3. All six cases for which a bone scintigram was available showed anextended uptake pattern. In five of the six, MR imaging revealed edema. CONCLUSION: Peritumoral BM edema wasfrequently seen (55.5%) in the GCTs of appendicular bone ; it was more often shown in association with a widetransition zone by plain radiographs.

Bone and Joint changes following Electrical Burn: Plain Radiographic findings

PURPOSE: To evaluate the plain radiographic findings of bone and joint changes following electrical burn. MATERIALS AND METHODS: This study involved 19 patients with 27 bone and joints regions which had sufferedelectrical injury. The most common input and output sites were, respectively, the hand(7/14) and foot (6/10).Three other sites were involved. Four cases involved osteomyelitis, and in four, amputation was performed. Weobserved bone and joint changes, changes following osteomyelitis and changes in the amputation stump. We analyzedthe difference between input and output changes, and when this was interesting, the average time of onset wasassessed. RESULTS: In bone and joint changes following electrical burn, the most frequent radiographic findingwas joint contracture (n=16). Other findings included osteolysis (n=8), articular abnormalites (n=6), periostitis(n=5), fracture (n=5), acro-osteolysis (n=2), and heterotopic bone formation (n=2). In cases involvingosteomyelitis(n=4), aggravation of underlying bone changes was noted. CONCLUSION: In electrical burn, variouschanges were noted in bone and joints, and input injury was more severe than that of output.

Radiographic Features of Tuberculous Osteitis in Greater Trochanter and Ischium

PURPOSE: To evaluate, if possible, the radiographic features of tuberculous osteitis in the greater trochanter and ischium, and to determine the cause of the lesions. MATERIALS AND METHODS: We retrospectively reviewed the plain radiographic findings of 14 ptients with histologically proven tuberculous osteitis involvingthe greater trochanter and ischium. In each case, the following were analyzed : morphology of bone destruction, including cortical erosion; periosteal reaction ; presence or abscence of calcific shadows in adjacent softtissue. On the basis of an analysis of radiographic features and correlation of the anatomy with adjacent structures we attempted to determine causes. RESULTS: Of the 14 cases evaluated, 12 showed varrious degrees of extrinsic erosion on the outer cortical bone of the greater trochanter and ischium ; in two cases, bone destruction was so severe that the radiographic features of advanced perforated osteomyelitis were simulated. Inaddition to findings of bone destruction, in these twelve cases, the presence of sequestrum or calcific shadows was seen in adjacent soft tissue. CONCLUSION: Tuberculous osteitis in the greater trochanter and ischium showed the characteristic findings of chronic extrinsic erosion. On the basis of these findings we can suggest that the selesions result from an extrinsic pathophysiologic cause such as adjacent bursitis.