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Biomedical subjects

J H Cho

Publications and source records attributed to J H Cho.

152 records · Page 9Linked to original sources
PubMedDate not supplied

MR imaging of tuberculous arthritis: clinical and experimental studies.

Signal-intensity characteristics of magnetic resonance (MR) images were assessed in five patients and in 10 rabbits with tuberculous arthritis. MR imaging findings were compared with histologic findings in the animal study. In both of clinical and experimental cases, tuberculous lesions showed both intermediate and high signal intensity on T2-weighted images, while they showed heterogeneously intermediate signal intensity on T1-weighted images. As T2-weighted images were compared with pathologic specimens, intermediate signal intensity corresponded to caseous necrosis, whereas high signal intensity related to granulomas or effusion. Postcontrast T1-weighted images showed enhancement at the peripheries rather than the centers of tuberculous lesions. These results indicate that tuberculous arthritis should be included in the differential diagnosis when intra-articular lesions with low or intermediate signal intensity are found on T2-weighted images.

Adult↗
PubMedDate not supplied

Chondromalacia of the knee: evaluation with a fat-suppression three-dimensional SPGR imaging after intravenous contrast injection.

Twenty-one MRI studies with a fat-suppression three-dimensional spoiled gradient-recalled echo in a steady state (3D SPGR) pulse sequence after intravenous contrast injection were evaluated to assess the accuracy in depicting chondromalacia of the knee. On the basis of MR images, chondromalacia and its grade were determined in each of five articular cartilage regions (total, 105 regions) and then the results were compared to arthroscopic findings. The sensitivity, specificity, and accuracy of MRI were 70%, 99%, and 93%, respectively. MR images depicted 7 of 11 lesions of arthroscopic grade 1 or 2 chondromalacia, and seven of nine lesions of arthroscopic grade 3 or 4 chondromalacia. The cartilage abnormalities in all cases appeared as focal lesions with high signal intensity. Intravenous contrast-injection, fat-suppression 3D SPGR imaging showed high specificity in excluding cartilage abnormalities and may be considered as an alternative to intra-articular MR arthrography when chondromalacia is suspected.

Adolescent↗
PubMedDate not supplied

Electroretinographic evaluation in adult diabetics.

In cross-sectional fashion, we recorded the maximal combined response and 30-Hz flicker responses in 178 adult diabetics and 40 normal controls according to the recommendations of the International Society of Clinical Electrophysiology of Vision. The oscillatory potentials were extracted from the maximal combined response by high-pass filtering. The clear media and attached retina were criteria for inclusion in this study. The data were statistically analyzed with the expectation that this procedure may provide a new feature that could have some clinical significance. Timing delays occurred more frequently than amplitude reductions in the maximal combined response and flicker responses, while amplitude reductions were more common in the first and second oscillatory potentials. The hypernormal b-wave amplitude was rare. The summed amplitude of the oscillatory potentials was highly correlated with the total power of the oscillatory potentials (the frequency domain). A reduction of the second oscillatory potential amplitude was more common than a reduction of the summed amplitude or total power. The electroretinographic component that demonstrates retinal dysfunction in the earlier stage may be a valuable indicator. In the early stage, a delay in the a-wave time and a reduction in the second oscillatory potential amplitude were the most frequent abnormalities: analysis of variance demonstrated that the summed amplitude of the oscillatory potentials and second oscillatory potential amplitude and time were the most sensitive measures of the diabetic retina. Hence, the second oscillatory potential amplitude may be the most sensitive and valuable indicator representing a quantitative measure of overall retinal dysfunction.

Adult↗
PubMedDate not supplied

Clinical significance of neck node metastasis in squamous cell carcinoma of the maxillary antrum.

PURPOSE: To further clarify the clinical significance of neck node metastasis in squamous cell carcinoma of the maxillary sinus (maxillary SCC). MATERIALS AND METHODS: The medical charts of the 116 patients with maxillary SCC were retrospectively reviewed. Twelve patients (10.3%) presented initially with neck node metastases, and 14 (13.5%) of 104 node-negative patients subsequently developed regional recurrence during the follow-up period. The high-risk factors for neck node metastasis, patterns of regional failure, and survival for node-positive patients were analyzed with the patient cohort that had largely been treated with radiation alone. RESULTS: Of the various factors, the tumor extension to the nasopharynx or oral cavity was the statistically significant determinants predictive of neck node metastasis at the initial diagnosis. During the follow-up period, regional failure was far less common than local failure (19.0% v 68.1%), and the majority of regional failures were accompanied by local recurrences. The oral cavity extension and control status of local disease were the high-risk factors for subsequent development of regional recurrence in node-negative patients. The overall 5-year survival rate for node-positive patients (16.7%) showed a poorer outcome compared with that for node-negative patients (31.3%), but it was similar to that of T4N0 patients (26.6%). Although patients who subsequently developed neck node recurrence during follow-up represented a dismal prognosis, uncontrolled local diseases in these patients still remained a major problem, resulting in a poor prognosis. CONCLUSIONS: Despite an unfavorable prognosis of patients with neck node metastasis, an aggressive trial to achieve maximum local control of the primary tumor was considered to be more important than elective neck treatments.

Adult↗
PubMedDate not supplied

MR appearance of distal femoral cortical irregularity (cortical desmoid).

PURPOSE: Our goal was to describe the MR appearance of distal femoral cortical irregularity (DFCI). METHOD: With plain radiographs and MR images of 100 knees, the presence of DFCIs was determined, and the shapes of DFCIs were classified into three subgroups: concave, convex, and divergent cortical shapes. Radiographic and MR shapes of DFCIs were compared. RESULTS: DFCIs were shown in various shapes on both the radiographs and the MR images. Forty-four DFCIs were found both on radiograph and by MR image. An additional 14 DFCIs were identifiable only on MR images. However, the majority of DFCIs showed an association between radiographic and MR shapes. MRI revealed that all 58 DFCIs were located at the attachment site of the medial gastrocnemius muscle. DFCIs were enhanced in three of the four patients who underwent postcontrast MR study. CONCLUSION: A good understanding of radiographic and MR findings of the DFCI may be of great help in the differential diagnosis of distal femoral lesions.

Adolescent↗
PubMedDate not supplied

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.

Adolescent↗