• Journal of Veterinary Clinics
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• v.25 no.1
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• pp.9-14
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• 2008

This purpose of this study was to describe and compare the radiographic and computed tomographic(CT) appearance of the experimentally induced Legg-Calve-Perthes Disease(LCPD) in dogs. LCPD was experimentally induced at the left femoral head in 7 litters of a dog. The lesions were evaluated with radiography, CT, and contrast CT every week from day 7 to day 70 after operation. Histopathologic examination was performed on 92th day after operation. Every images were evaluated according to the staging system of the osteonecrosis published by Association Research of Circulation Osseous in 1997 and the scoring(0-4). On CT scan, diffuse porotic lesion and focal sclerotic lesion were detected on day 14 and on day 21 after operation, respectively. Subchondral fracture, articular collapse and crescent sign with decreased attenuation were shown on day 28 after operation for the first time and no change of the sign were detected from operation day 9 to day 70 after operation. Focal porotic lesion and irregular radiopacity of femoral head were detected on day $41{\pm}7.48$ and on day $51{\pm}5.29$ after operation respectively on radiographs. In scoring evaluation, 2.00 was scored on day 14 after operation on CT scan, on day 56 after operation on radiographs, respectively This study has shown that CT is more suitable for early diagnosis of LCPB and has superior sensitivity than radiography. Also, CT has been expected to be important for staging and treatment of LCPD.

• Radiation Oncology Journal
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• v.27 no.1
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• pp.1-9
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• 2009

There has been recent interest in radiation-induced bone injury in clinical conditions, especially for pelvic insufficiency fracture (PIF). A PIF is caused by the effect of normal or physiological stress on bone with demineralization and decreased elastic resistance. Pelvic radiotherapy (RT) can also contribute to the development of a PIF. A PIF has been regarded as a rare complication with the use of megavoltage equipment. However, recent studies have reported the incidence of PIFs as $8.2{\sim}20%$ after pelvic RT in gynecological patients, an incidence that was higher than previously believed. The importance of understanding a PIF lies in the potential for misdiagnosis as a bony metastasis. If patients complain of pelvic pain after whole-pelvis radiation therapy, the presence of a PIF must be considered in the differential diagnosis. The use of multibeam arrangements and conformal RT to reduce the volume and dose of irradiated pelvic bone can be helpful to minimize the risk of fracture. In addition to a PIF, osteonecrosis and avascular necrosis of the femoral head can develop after radiation therapy. Osteoradionecrosis of the pelvic bone is a clinical diagnostic challenge that must be differentiated from an osseous metastasis. A post-radiation bone sarcoma can result as a long-term sequela of pelvic irradiation for uterine cervical cancer.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.177-182
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• 2009

Purpose : To compare the subchondral fracture on plain radiography and MR image as a method for assessing osteonecrosis in Legg-Calve-Perthes(LCP) pateients. Materials and methods: We retrospetively reviewed 15 hip joint MR images and plain radiography which visualized subchondral fracture. With basis of the Salter-Thompson classification, extent of necrosis was graded group A to B, as follows; Group A = < 50%, B = > 50%. On PACS workstation, necrotic area of each MR image was measured to calculate the volume of necrotic portion: volume = necrotic area $\times$ slice thickness. Necrotic areas on MR images were graded group A to B and results were compared with that measured in Salter-Thompson classification. On follow up, bone resorption was measured and the extent was compared with subchondral fracture representing necrotic area and that on MR volume method respectively. Results : In 9 joints of 15 hip joints (60%), the degree of necrosis in Salter-Thompson classification on plain radiographs was different from that on MR volume method. Based on plain radiographs by Salter-Thompson classification, the degree of necrosis was overestimated in 6(67%) joints, and underestimated in 3(33%) joints compared with MR volume method. On follow up study, bone resorption was not correlated with necrotic extent of subchondral fracture and MR volume method. Conclusion : The extent of femoral head necrosis measured by subchondral fracture was different from that measured by MR and was not correlated with bone resorption on follow up. Therefore, usefulness of subchondral fracture as a prognostic factor may be limited.