Kyung-Nam Ryu

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.

Calcific tenosynovitis associated with calcific myonecrosis of the leg: imaging features

Abstract The findings with histologically proven calcific tenosynovitis of the tibialis anterior tendon associated with calcific myonecrosis are described. This case emphasizes the typical appearance of this unusual relationship such as peripheral plaque-like calcifications of the tendon sheath, fluid-calcium levels, presentation as painless mass, and calcification and liquefaction of muscle bundles.

Osteonecrosis in patients with systemic lupus erythematosus:MR imaging and scintigraphic evaluation

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.

Assessment of metabolic changes in the striatum of a MPTP-intoxicated canine model: in vivo 1H-MRS study of an animal model for Parkinson's disease

Parkinsons disease (PD) is a neurodegenerative disorder characterized by the progressive loss of the dopaminergic neurons in the substantia nigra pars compacta, which projects to the striatum. We induced a selective loss of nigrostriatal dopamine neurons, by infusing the mitochondrial complex 1 inhibitor 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) into adult beagle dogs (N=5). Single voxel ¹H water suppressed magnetic resonance spectroscopy (¹H-MRS) at 3 T was used to assess the metabolic changes in the striatum of canine before and after MPTP intoxication. The metabolite spectra obtained from the striatum (voxel size: 2 cm³) showed a lower N-acetyl aspartate to total creatine (creatine+phosphocreatine) ratio after MPTP intoxication. There were no significant differences in other metabolite ratios such as glutamate+glutamine, choline-containing compounds (glycerophosphocholine+phophorylcholine and myo-inositol). Our findings indicated that ¹H-MRS is a sensitive, noninvasive measure of neural toxicity and biochemical alterations of the striatum in a canine model of PD, and further studies are needed to confirm brain metabolic changes in association with progression of MPTP-intoxication.

MRI of chondromyxoid fibroma

Background Chondromyxoid fibroma is a rare benign primary bone tumor of cartilage. Despite a characteristic radiographic appearance, chondromyxoid fibroma with atypical radiographic findings may mimic more common tumors. Purpose To describe the MR findings of chondromyxoid fibroma. Material and Methods MR images of 19 histopathologically confirmed chondromyxoid fibromas were retrospectively analyzed for signal intensity, periosteal reaction, adjacent abnormal bone marrow and soft tissue signal, and patterns of contrast enhancement. Results All cases of chondromyxoid fibroma showed hypointense to intermediate signal intensity and internal hyperintense foci were observed in seven (37%) cases on T1-weighted images. On T2-weighted images, all lesions were hyperintense: peripheral intermediate signal band with central hyperintense signal in 11 (58%) of 19 lesions, whereas diffusely hyperintense with heterogeneous pattern in eight (42%). Periosteal reaction was observed in 11 (58%) of 19 cases. Adjacent abnormal bone marrow or soft tissue signal was observed in 12 (63%) or 14 (74%) of 19 cases, respectively. On contrast-enhanced T1-weighted images, peripheral nodular enhancement was observed in 69% (11/16) and diffuse contrast enhancement was observed in 31% (5/16) with homogeneous (n = 3) or heterogeneous (n = 2) patterns. Among the cases with peripheral nodular enhancement, the peripheral nodular enhancing portion generally corresponded to the peripheral intermediate signal band on T2-weighted images, although the peripheral enhancement was not as wide as a band of intermediate signal intensity. On the other hand, the central non-enhancing portion generally corresponded to the central hyperintense signal intensity on T2-weighted images. Conclusion The helpful features of chondromyxoid fibroma are the peripheral intermediate signal band and central hyperintense signal on T2-weighted images, generally corresponding to the peripheral nodular enhancement and central non-enhancing portion on contrast-enhanced T1-weighted images, respectively.

Posterior root of lateral meniscus: the detailed anatomic description on 3T MRI.

Background Although there have been some attempts to reveal the anatomy of the posterior root of the lateral meniscus (PRLM) through cadaver studies, arthroscopy, or imaging, it has not yet been described fully. Purpose To describe clearly the unique features of the PRLM, including its course, configuration, and size, using 3.0-T magnetic resonance imaging (MRI). Material and Methods A total of 105 knee 3.0-T MR examinations of 103 patients with arthroscopically proven intact PRLM were reviewed retrospectively. Based on fat-saturated, proton-density-weighted (PDW) axial/coronal images and PDW sagittal images, the course, configuration, and attachment sites of the PRLM were evaluated. Results The majority of PRLM (76.2%) had two attachment sites: the medial tubercle along the intertubercular crest, just posteromedial to the tibial attachment of the anterior cruciate ligament (ACL), and the posterior slope of the lateral tubercle. The remaining cases (23.8%) had a solitary insertion on the intertubercular area (17 cases), or the posterior slope of the lateral tubercle (eight cases). The PRLM of the intertubercular area appeared as a dark signal line parallel to the tibial plateau on the mid-sagittal image and dark signal foci traversing the intertubercular crest on contiguous coronal images. Conclusion The PRLM inserts mainly in the intertubercular area with a thin, long anterior extension to the point just posteromedial to the tibial attachment of the ACL. It is well delineated on PDW 3.0-T MRI as a dark signal line parallel to the tibial plateau on mid-sagittal images and dark signal foci traversing the intertubercular crest on contiguous coronal images.