Risk period for developing osteonecrosis of the femoral head in patients on steroid treatment.

Patients who require long-term steroid use are at risk for the development of osteonecrosis. However, the risk period for developing osteonecrosis of the femoral head has not yet been defined. The authors attempted to determine the onset of osteonecrosis of the femoral head following steroid treatment. Medical record data of patients with steroid-related osteonecrosis of the femoral head from four university hospitals were reviewed. Information was collected regarding the duration and dose of steroid use for patients who were diagnosed at the early stage by magnetic resonance imaging (MRI) without positive findings on plain radiographs (Association Research Circulation Osseous stage I osteonecrosis). Twenty-two patients were diagnosed at Association Research Circulation Osseous stage I. There were eight male and 14 female patients ranging in age from 17 to 60 years (mean 33). The total dose of steroid, which was used until the time of detection of osteonecrosis by MRI, ranged from 1800 to 15 505 mg prednisolone or its equivalent (mean 5928 mg). The period from the start of steroid treatment to the diagnosis by MRI ranged from 1 month to 16 months (mean 5.3 months). Twenty-one of 22 patients were diagnosed within 12 months of the initiation of steroid treatment. The duration of steroid treatment within this period ranged from 1 month to 12 months (mean 4.5 months). There may be a risk period of 12 months for developing femoral head osteonecrosis in patients receiving long-term steroid treatment. Close observation and more aggressive screening are recommended within the first year of long-term steroid treatment to prevent advanced osteonecrosis of the femoral head.

Iliacus hematoma and femoral nerve palsy after revision hip arthroplasty: a case report.

Femoral nerve palsy occurred in a 65-year-old man after he had undergone a revision total hip arthroplasty using cementless components. The magnetic resonance imaging scan showed a mass in the iliacus muscle. The mass showed increased signal intensity on T1-weighted and T2-weighted spin-echo images and contained linear septa and a nodule. The gadolinium-enhanced T1-weighted image showed a rim of significant enhancement in the nodule. The findings of magnetic resonance images were suggestive of iliacus hematoma and of liposarcoma. The patient underwent surgery, and the mass was identified as an iliacus hematoma. The femoral nerve was stretched by the hematoma. After removal of the hematoma, the nerve palsy was improved completely. Iliacus hematoma may occur after total hip arthroplasty, even without anticoagulant therapy. The hematoma might appear to be a liposarcoma on magnetic resonance imaging scans.

Bone marrow edema and associated pain in early stage osteonecrosis of the femoral head: prospective study with serial MR images.

PURPOSE: To determine whether the marrow edema around focal osteonecrosis on magnetic resonance (MR) images is associated with clinical symptoms. MATERIALS AND METHODS: Thirty-three patients with 37 hips showing early stage osteonecrosis of the femoral head were followed up at 3-month intervals with clinical evaluation, conventional radiography, and serial MR imaging. RESULTS: Seven (50%) of 14 symptomatic hips showed marrow edema around focal osteonecrosis on initial MR images, whereas only one (4%) of 23 asymptomatic hips showed edema (P < .01). Six (86%) of seven hips that were moderately to severely painful were associated with surrounding marrow edema. All eight hips showing osteonecrosis with marrow edema at the initial MR examination had joint effusion and exhibited intense radionuclide uptake in the proximal femur, which corresponded to the extent of edema on MR images. In all eight hips, the marrow edema resolved on follow-up MR images, and the pain subsided with the resolution of edema. CONCLUSION: The results of this study suggest that the combination of marrow edema of the proximal femur and focal osteonecrosis of the femoral head are strongly associated with hip pain in early stage osteonecrosis, even prior to collapse. Pain improvement usually parallels the resolution of edema.

Fatty marrow conversion of the proximal femoral metaphysis in osteonecrotic hips.

To determine whether fatty marrow conversion of the proximal femoral metaphysis is related to osteonecrosis of the femoral head using a marrow conversion index ([signal intensity of the proximal femoral metaphysis/signal intensity of the greater trochanter] x 100 in T1 weighted magnetic resonance images), a case control study was conducted on 42 osteonecrotic hips in 28 patients. The 28 patients (42 osteonecrotic hips) were matched with 84 control patients (84 normal hips) for gender, age (5-year range), and time of presentation (1-year range). The marrow conversion index was measured in each hip studied. The index was 90.2% (standard deviation, 8.2%) in osteonecrotic hips and 75.1% (standard deviation, 9.1%) in matched controls. By conditional logistic regression, a 5% increase in the index was associated with 3.6 times increase of the odds ratio of osteonecrosis and a 10% increase with a 12.9 times increase of the odds ratio. The marrow conversion index, which reflects the ratio of fatty marrow conversion of the proximal femoral metaphysis to that of the greater trochanter measured on T1 weighted magnetic resonance images, is increased in osteonecrotic hips.

Hepatocellular carcinoma in North America: a multiinstitutional study of appearance on T1-weighted, T2-weighted, and serial gadolinium-enhanced gradient-echo images.

OBJECTIVE: The purpose of this study was to define the common appearances of hepatocellular carcinoma (HCC) in patients in North America by analyzing T1-weighted, T2-weighted, and serial gadolinium-enhanced gradient-echo images interpreted by radiologists at multiple institutions in North America. MATERIALS AND METHODS: One hundred thirteen consecutive patients with HCC from eight institutions were included in this retrospective case series. Inclusion criteria included MR imaging examinations performed on 1.5-T MR imagers using T1-weighted breath-hold spoiled gradient-echo images, T2-weighted images, and serial gadolinium-enhanced spoiled gradient-echo images. Diagnosis was established by histology in all patients. Images were analyzed retrospectively for lesion count, lesion diameter as less than or equal to 1.5 cm and greater than 1.5 cm, and signal intensity, by individual experienced radiologists at each institution. RESULTS: We found 354 HCC lesions in the 113 patients. Tumors were solitary in 63 patients, multifocal in 45 patients, and diffuse in five patients. Lesion appearance on combined T1-weighted, T2-weighted, and immediate gadolinium-enhanced spoiled gradient-echo images was as follows: 102 lesions (29%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited diffuse heterogeneous enhancement; 52 lesions (15%) were isointense on both T1- and T2-weighted images and exhibited diffuse homogeneous enhancement (all of these lesions measured < or = 1.5 cm in diameter); 50 lesions (14%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited diffuse homogeneous enhancement; 33 lesions (9%) were hypointense on T1-weighted images, were hyperintense on T2-weighted images, and exhibited predominantly peripheral rim enhancement; and 27 lesions (8%) were hypointense on T1-weighted images, were isointense on T2-weighted images, and exhibited diffuse homogeneous enhancement. The remaining 90 lesions showed less common patterns. The appearance of HCCs greater than 1.5 cm and of HCCs less than or equal to 1.5 cm was significantly different (p = .001). The appearance of histologically proven HCCs is separately described. CONCLUSION: The combination of hypointensity on T1-weighted images, hyperintensity on T2-weighted images, and diffuse heterogeneous enhancement was the most common appearance of HCC on MR images in a multiinstitutional patient population in North America. Small HCCs measuring less than or equal to 1.5 cm were frequently isointense on both T1-weighted and T2-weighted images and may be detected on immediate gadolinium-enhanced images only as diffuse homogeneously enhancing lesions.

Age-related marrow conversion in the proximal metaphysis of the femur: evaluation with T1-weighted MR imaging.

PURPOSE: To determine the normal chronologic changes in fatty marrow conversion of the proximal femoral metaphysis at magnetic resonance (MR) imaging. MATERIALS AND METHODS: The "marrow conversion index," (signal intensity of the proximal femoral metaphysis divided by signal intensity of the greater trochanter) x 100, was measured in 182 hips of 91 patients who had no evidence of osteonecrosis or diseases involving bone marrow, no history of steroid treatment, and no other risk factors for osteonecrosis. The results were evaluated according to patient age and sex. RESULTS: The index showed a progressive linear increase with age regardless of sex. The index was 65.4% +/- 5.6 (standard deviation) in patients aged 15-19 years and increased monotonously with age to 87.5% +/- 7.0 in patients aged 60-79 years. Simple linear regression of the index according to age group showed that the marrow conversion index is roughly equal to 63 + 4 x Z (p < .001), where Z is 1.5 for patients aged 15-19 years, 2.0 for patients aged 20-29 years, 3.0 for patients aged 30-39 years, 4.0 for patients aged 40-49 years, 5.0 for patients aged 50-59 years, and 6.0 for patients aged 60-79 years. CONCLUSION: There is a linear association of marrow conversion index and age. The estimating equation may provide baseline information for the marrow conversion index.

Cloning of upstream sequences responsible for cell cycle regulation of the Nicotiana sylvestris CycB1;1 gene.

To understand the mechanisms involved in the regulation of the mitotic cyclin B Nicta; CycB1;1 expression, we have cloned the Nicotiana sylvestris cyclin gene, Nicsy; CycB1;1, whose coding sequence is homologous to that of Nicta;CycB1;1 cDNA. The structure and the function of its 5'-flanking region, 1149 bp upstream of the first start codon, was analysed. By producing stably transformed cells of a synchronized culture with the Nicsy;CycB1;1 promoter/beta-glucuronidase (gus) reporter gene fusion, we demonstrate that the 1149 bp promoter fragment mediates a gus transcriptional oscillation, indistinguishable from that of endogenous Nicsy;CycB1;1 cyclin B transcripts. Transient GUS activity in BY-2 protoplasts reveals that promoter activity is considerably reduced by shortening the 5'-flanking region to 538 or 320 bp. Furthermore, the 320 bp fragment no longer mediates the observed transcriptional regulation of the 1149 bp Nicsy;CycB1;1 promoter in BY-2 protoplasts isolated from synchronized cells.

Hemiazygos continuation of a left inferior vena cava draining into the right atrium via persistent left superior vena cava: demonstration by helical computed tomography.

We report an unusual case of hemiazygos continuation of a left inferior vena cava draining into the right atrium via the persistent superior vena cava. Spiral computed tomography (CT) showed the course and the flow direction of this vena caval anomaly in a real-time manner, obviating conventional venography.