Osteonecrosis in patients with systemic lupus erythematosus

This study was to describe the findings of osteonecrosis in patients with SLE at MR and scintigraphic imaging. Among 415 patients with SLE, 37 patients were diagnosed to have osteonecrosis. MR images and bone scintigraphs were analyzed for sites of involvement, signal intensity, bilaterality and multiplicity. MR imaging features of osteonecrosis in patients with SLE included isointense signal intensity relative to adjacent bone marrow, hypointense rim, marginal enhancement and unusual involvement of flat bones. Bilateral and multiple involvements were common.

Central osteophytes in the knee: prevalence and association with cartilage defects on MR imaging

OBJECTIVE

The objective of this study was to determine the prevalence and location of central osteophytes in patients referred for MR imaging of the knee and the relationship of central osteophytes to articular cartilage defects, marginal osteophytes, meniscal tears, and anterior cruciate ligament tears as seen on MR imaging.

MATERIALS AND METHODS

Two hundred consecutive patients referred for MR imaging of the knee were evaluated for central osteophytes, articular cartilage defects, marginal osteophytes, meniscal tears, and anterior cruciate ligament tears. A 1.5-T scanner was used, and assessments were made by consensus of two experienced musculoskeletal radiologists. Seven patients were excluded, leaving 193 patients in the study population.

RESULTS

The prevalence of central osteophytes in the knee was 15% (35 central osteophytes in 29 patients). Patients with central osteophytes were older (mean age, 52 years versus 38 years), weighed more (mean weight, 204 lb [92 kg] versus 174 lb [78 kg]), had more articular cartilage defects (mean, 4.3 versus 1.3), and had more marginal osteophytes (mean, 3.9 versus 1.1) than patients without central osteophytes (p < 0.0001, Student's t test). Patients with central osteophytes were more likely to have a meniscal tear (p = 0.004, chi-square test), but they were not more likely to have an anterior cruciate ligament tear. All central osteophytes were associated with articular cartilage defects at the same location, which were full or near-full thickness on MR imaging for 32 of 35 central osteophytes.

CONCLUSION

Central osteophytes are common in patients referred for MR imaging of the knee. When central osteophytes are seen in the knee there is a high likelihood of an associated full thickness or near-full thickness articular cartilage defect.

Superior labral anterior posterior (SLAP) lesions of the glenoid labrum: reliability and accuracy of MR arthrography for diagnosis

PURPOSE

To determine the reliability and accuracy of magnetic resonance (MR) arthrography for the diagnosis of superior labral anterior posterior (SLAP) tears.

MATERIALS AND METHODS

The MR arthrograms in 80 patients who underwent arthroscopy and MR arthrography during a 54-month period were retrospectively reviewed. MR arthrograms were independently scored by three observers for the presence and type of SLAP lesion. Type I SLAP lesions were regarded as negative as they most often are not clinically relevant. Interobserver agreement for detection of SLAP lesions was calculated by using kappa coefficients. The differences in areas under the receiver operating characteristic (ROC) curves were assessed with a univariate z score test.

RESULTS

At arthroscopy, there were 25 SLAP tears: type II (n = 22), type III (n = 2), and type IV (n = 1). Sensitivity, specificity, and accuracy of each reader were 92%, 84%, and 86%; 92%, 82%, and 85%; and 84%, 69%, and 74%, respectively. Interobserver agreement for SLAP tears was substantial (kappa = 0.77) to moderate (kappa = 0.52, kappa = 0.44). The areas under the ROC curves for each reader were 0.94, 0.93, and 0.83, which were not significantly different.

CONCLUSION

MR arthrography of the shoulder is reliable and accurate for detection of SLAP tears.

Incidence and significance of demonstrating the meniscofemoral ligament on MRI

The aim was to evaluate how often MRI can detect the meniscofemoral ligament and if there is any relationship with the presence of lateral meniscal tears. Sagittal and coronal MR images of 138 patients with arthroscopically proven meniscal tears were included in this study. MR images were retrospectively reviewed for the presence of a meniscofemoral ligament and a lateral meniscal tear. The chi 2 test was used for statistical analysis. Either one or both meniscofemoral ligaments were shown in 114 (83%) of 138 patients on MR images. In 61 cases with a lateral meniscal tear, the meniscofemoral ligament was present in 82% (50/61) and absent in 18% (11/61). In 77 cases without lateral meniscal tear, the meniscofemoral ligament was present in 83% (64/77) and absent in 17% (13/77). A significant correlation was not established between the meniscofemoral ligament and lateral meniscal tear (p = 0.85).

Chondroblastoma: MR characteristics with pathologic correlation

PURPOSE

The purpose of this study was to describe the MR findings of chondroblastoma with pathologic correlation.

METHOD

In 22 patients with pathologically proven chondroblastoma, MR signal characteristics were correlated with pathological findings.

RESULTS

On T2-weighted images, 12 (55%) lesions were hyperintense with hypointense areas in 9 lesions, whereas 10 (45%) were hypointense. Therefore, 19 of 22 (86%) lesions with pathologic correlation had hypointense areas entirely (n = 10) or partly (n = 9) on T2-weighted images. On gadolinium-enhanced images, 13 (59%) lesions showed lobular enhancement and 9 (41%) showed marginal and septal enhancement. Low signal intensity on T2-weighted MR images was most strongly associated with an abundance of immature chondroid matrix, hypercellularity of the chondroblasts, calcifications, and hemosiderin on histology.

CONCLUSION

Chondroblastoma was found to show hypointense portions on T2-weighted images. Signal intensity on T1- and T2-weighted MR images in chondroblastoma was dependent on the amounts of histopathological components.

Nonossifying fibroma: characteristics at MR imaging with pathologic correlation

PURPOSE

To correlate the findings of nonossifying fibroma at magnetic resonance (MR) imaging with those at pathologic examination.

MATERIALS AND METHODS

In 19 patients (age range, 8-25 years; mean age, 14 years) with pathologically proved nonossifying fibroma, MR images were analyzed for signal intensity and patterns of contrast enhancement. Findings at MR imaging and biopsy were correlated.

RESULTS

On T1-weighted images, all nonossifying fibromas had low signal intensity compared with that of skeletal muscle. On T2-weighted images, 15 lesions (79%) were hypointense and four (21%) were hyperintense. On gadolinium-enhanced images, intense contrast enhancement was seen throughout 15 lesions (heterogeneous pattern in 12 and homogeneous in three) and in the margins and septa in four. Extensive hypercellular fibrous tissue and hemosiderin seen at pathologic examination were depicted with low signal intensity on T2-weighted MR images.

CONCLUSION

The distinguishing features of nonossifying fibroma included hypointensity and septation on T2-weighted images. Signal intensity on T1- and T2-weighted MR images and the patterns of contrast enhancement were dependent on the amounts of hypercellular fibrous tissue, hemosiderin, hemorrhage, collagen, foamy histiocytes, and bone trabeculae.

The plica syndrome: diagnostic value of MRI with arthroscopic correlation

PURPOSE

Our goal was to evaluate the diagnostic value of MRI in plica syndrome.

METHOD

MR images of a patient group (n = 55) with arthroscopically confirmed pathologic mediopatellar plicae were retrospectively analyzed and compared with those of a control group (n = 100). We obtained axial multiplanar gradient-recalled (MPGR), axial T1-weighted, and sagittal T2-weighted MR images. MR images were assessed for the width and length of all medial plicae.

RESULTS

In the diagnosis of plica syndrome, sensitivity and specificity were 73 and 78% on axial MPGR images, 71 and 83% on sagittal T2-weighted images, and 95 and 72% on combination of both images, respectively. The incidence of pathologic medial plica increased with a criterion of extension beyond the medial end of the patella on axial MPGR images.

CONCLUSION

MRI is a useful screening method in the diagnosis of plica syndrome.

Evaluation of the effects of high dose irradiation on canine thigh muscle by follow-up magnetic resonance imaging and phosphorus-31 magnetic resonance spectroscopy

RATIONALE AND OBJECTIVES

The authors investigate alterations of proton T1 and T2 relaxation times and phosphorus metabolites of canine thigh muscle tissue after high dose x-ray irradiation by follow-up magnetic resonance imaging (MRI) and phosphorus-31 (31P) magnetic resonance spectroscopy (MRS).

METHODS

A group of 20 dogs was used for MRI and in vivo 31P MRS. Single doses of 5,000 and 10,000 cGy were delivered to the right thigh muscle of groups of 10 dogs each. All MRI and 31P MRS examinations were performed before irradiation and 1, 7, 14, 28, 42, and 56 days after irradiation. For measurement of T1, repetition time (TR) was measured at 300, 500, 1000, 1500, 2000 msec and echo time (TE) was fixed at 12 msec. Also, for measurement of T2, TE was measured at 20, 40, 60, and 80 msec and TR was fixed at 2000 msec. Image selected in vivo spectroscopy (ISIS) pulse sequence was used to obtain 31P MR spectra. Peak areas for each phosphorus metabolite were measured using a Marquart algorithm.

RESULTS

Magnetic resonance imaging signal began to change at 28 days after a single dose of 10,000 cGy, whereas there was no significant MRI signal change until 56 days after a single dose of 5,000 cGy. Also, extensive MRI signal changes were observed at 42 days after a single dose of 10,000 cGy. Significant correlation was established between T2 and a lapse of time although there was no correlation between T1 and a lapse of time. T2 value increased substantially corresponding to the time period after x-ray irradiation. Although MR spectral change was not observed until 42 days after a single dose of 5,000 cGy, it began at 14 days after a single dose of 10,000 cGy. And, significant MR spectral changes were observed at 28 and 42 days. Inorganic phosphate and phosphodiesters signal intensities increased while phosphocreatine signal intensity decreased. The pH value was 7.22 +/- 0.05 at control, and 6.98 +/- 0.04 at 42 days after a single dose of 10,000 cGy.

CONCLUSIONS

The postirradiation follow-up MRI and 31P MRS studies demonstrated that morphologic and metabolic changes were dependent upon the x-ray dose and a lapse of time.

Recurrent parosteal osteosarcoma of the talus in a 2-year-old child

Parosteal osteosarcoma is an uncommon, low-grade malignant bone tumor and is found in an older age group than conventional osteosarcoma. We present a talar parosteal osteosarcoma that recurred twice in a 2-year-old child. To our knowledge, this is the youngest patient reported with a parosteal osteosarcoma. The talus is an unusual site for parosteal osteosarcoma. Inadequate resection due to a diagnosis of juxtacortical chondroma resulted in recurrence of the tumor. The age of the patient, the thick cartilaginous cap, and well-differentiated trabecular bone all contributed to the critical erroneous diagnosis.

Resistive index of the intrascrotal artery in scrotal inflammatory disease

PURPOSE

To investigate the utility of the resistive indices (RIs) of the epididymal and intratesticular arteries, and to establish diagnostic criteria for scrotal inflammatory disease on the basis of quantitative color Doppler sonography.

MATERIAL AND METHODS

We prospectively examined 29 consecutive patients with scrotal pain, and 15 normal control subjects. The RIs of the intratesticular and epididymal arteries were obtained from color Doppler sonographs.

RESULTS

The RIs of the testicular artery in epididymoorchitis were significantly lower than those in normal control subjects and in epididymitis (p < 0.01) while the RIs of the testicular artery in epididymitis and control subjects were similar (p > 0.5). With a cut-off value of RI = 0.5, sensitivity, specificity, accuracy, and positive and negative predictive values were 91%, 94%, 94%, 83%, and 77% respectively. The mean RI of the epididymal arteries in epididymitis and epididymoorchitis was 0.49 +/- 0.11. A high level of diagnostic accuracy in scrotal inflammatory disease was achieved when the RIs of the intratesticular and epididymal arteries were less than 0.5 and 0.7 respectively.

CONCLUSION

The RI of the intrascrotal artery would give a more objective evaluation than subjective assessment and could provide diagnostic criteria for scrotal inflammatory disease.

The impact of HLA-DRB1*0405 on disease severity in Korean patients with seropositive rheumatoid arthritis

Many reports have described HLA-DRB1 genes as having an influence on disease severity and susceptibility in rheumatoid arthritis (RA). Studies were undertaken to define the effect of RA-associated alleles on disease severity in Korean patients with seropositive RA. The results indicate that the most common RA susceptibility allele, HLA-DRB1*0405, is significantly associated with bony erosion, joint deformity and extra-articular manifestations. However, RA-associated alleles in Koreans have less effect on nodular disease than in Caucasians. This suggests that the presence of RA-associated alleles, especially HLA-DRB1*0405, seems to be a prognostic marker for severe erosive disease in Koreans.

Fibrous dysplasia: MR imaging characteristics with radiopathologic correlation

OBJECTIVE

The purpose of this study was to describe the findings of MR imaging of fibrous dysplasia and to evaluate the correlation between radiologic and pathologic findings.

MATERIALS AND METHODS

MR images of 13 proven cases of fibrous dysplasia were analyzed for signal intensity, hypointense rind, internal septations, cystic changes, soft-tissue extension, and patterns of contrast enhancement.

RESULTS

All cases of fibrous dysplasia showed low signal intensity on T1-weighted MR images. Five cases (38%) were hypointense on T2-weighted MR images, and the other eight cases (62%) were hyperintense. Hypointense rind was seen in 10 cases (77%); internal septations were seen in three cases (23%); and cystic changes was seen in two cases (15%). Soft-tissue extension was observed in four cases (31%), including one case (8%) with a pathologic fracture. After gadolinium infusion, central contrast enhancement was noted in eight cases (73%), and peripheral rim enhancement was noted in three cases (27%). Numerous bony trabeculae, confirmed pathologically, caused a hypointense signal intensity on T2-weighted images.

CONCLUSION

Patients with fibrous dysplasia showed a correlation between radiologic and pathologic findings. Our results showed that T1-weighted images reveal fibrous dysplasia as hypointense, and T2-weighted images reveal fibrous dysplasia as either hyperintense or hypointense. Signal intensity on T1- and T2-weighted images and the degree of contrast enhancement on T1-weighted images depended on the amount and degree of bony trabeculae, cellularity, collagen, and cystic and hemorrhagic changes.