No abstract available.
Bone Density*

To evaluate the value of MR imaging in the examination of ligament injury of the knee, we retrospectively analysed the MR images of 61 injured knees of 60 patients. The presence of tear was determined by arthroscopy in all cases. Anterior/posterior cruciate ligaments(ACL/PCL) were demonstrated by sagittal images. Media/lateral collateral ligaments(MCL/LCL) were evaluated on coronal images. The diagnostic accuracy were 91.8%, 96.7% and 100% for ACL, PCL and MCL, respectively. The specificity for the lateral collateral ligament was 100%. It is concluded that magnetic resonance imaging is an accurate method in detecting injury of the ligaments of the knee.
Arthroscopy ; Humans ; Knee* ; Lateral Ligament, Ankle ; Ligaments* ; Magnetic Resonance Imaging ; Methods ; Retrospective Studies ; Sensitivity and Specificity ; Tears

PURPOSE: To evaluate the findings and the role of contrast enhanced magnetic resonance imaging in avascular necrosis of femoral head. MATERIALS AND METHODS: Sixteen patients with avascular necrosis of femoral head were examined with MRI. Tl-weighted and T2-weighted images and contrast-enhanced Tl-weighted images were obtained. Enhancing characteristics of the necrotic area and synovium were determined. Also a change of the disease extent after enhancement was assessed. RESULTS: Twenty seven avascular necrosis of the femoral head including 11 cases of bilateral lesion were detected. Fifteen cases revealed collapse of the femoral head. The portions of the lesion with low signal intensity on Tl-weighted images and high signal intensity on T2-weighted images showed contrast enhancement in 15 cases. However, the portions with low signal intensities both on T1 and T2-weighted images showed enhancement in one case. There was no significant change of the disease extent after enhancement. Synovium showed enhancement in 18 cases, and joint effusion was detected in 23 cases. CONCLUSION: Contrast enhanced MR images may be helpful in predicting histopathologic findings of avascular necrosis of the femoral head, but not useful for evaluating the extent of disease.
Head* ; Humans ; Joints ; Magnetic Resonance Imaging* ; Necrosis* ; Synovial Membrane

PURPOSE: To describe the magnetic resonance (MR) findings of pigmented villonodular synovitis(PVNS) of the knee, and to evaluate the clinical value of MR in the diagnosis of PVNS. MATERIALS AND METHODS:MR imagings of seven patients with PVNS were studied. The type of lesion, presence of bony erosion, the signal intensity, and the relationship between contrast enhancement and signal intensity on T2-weighted images were analyzed, retrospectively. RESULTS: The lesion was mainly villous in three patients and nodular in four, and bony erosion was seen in one patient. On T2-weighted image, the signal intensity of the villous form was mixed iso- and hypointense in two, hypointense in one, and that of the nodular form was heterogeneous with hypo-, iso-, and hyperintensities. The hypointense portion on T2-weighted image showed poor contrast enhancement, which may suggest hemosiderin deposition or advanced fibrosis. The iso- or hyperintense portion on T2-weighted image showed strong enhancement, which suggest active cellular proliferation. CONCLUSION:MR imaging could be a very useful modality in the diagnosis as well as prediction of histological findings of the PVNS.
Cell Proliferation ; Diagnosis ; Fibrosis ; Hemosiderin ; Humans ; Knee* ; Magnetic Resonance Imaging* ; Retrospective Studies ; Synovitis, Pigmented Villonodular*

Magnetic resonance (MR) imaging was performed in 41 patients with compression fracture of the spine. MR images of 14 patients with acute spinal trauma (within recent 1 month), eight patients with chronic trauma (over 1 month), and 19 patients with malignant cause without history of trauma were analyzed, retrospectively. Low signal intencities on T1-weighted images and high signal intensities on T2-weighted images were noted in 86% (12/14) of patients with acute trauma, Iso-signal intensities on all pulse sequences were noted in 50%(4/8) of patients with chronic trauma. Low signal intensities on T1-weighted images and high signal intensities on T2-weighted images were noted in 100%(19/19) of patients with metastatic compression fracture. Contrast enhancement was observed in all the cases of acute trauma(4/4) and metastases(18/18), whereas only 20% (1/5) of chronic trauma showed enhancement. Fragmentation was seen in 35% (5/14) of patients with acute trauma, in 25%(2/8) with chronic trauma, and not seen in the patients with metastasis. In conclusion, acute traumatic compression fracture can not be differentiated from malignant cause by MR signal intensity or contrast enhancement, but chronic compression fracture can be distinguished from metasasis. Fragmentation may suggest traumatic compression fracture. So MRI could be a useful method in differentiating the benign compression fractures from the pathologic ones caused by malignancy.
Fractures, Compression* ; Humans ; Magnetic Resonance Imaging ; Methods ; Neoplasm Metastasis* ; Retrospective Studies ; Spine

PURPOSE: Algorithms to get cross-sectional bone density pattern(transverse histogram) to predict the loosening of hip prosthesis using DXA(Dual X-ray Absorptiometry) have been developed. We performed this study to analyze the correlation between radiologic findings and densitometric pattern of the THRA(Total Hip Replacement Arthroplasty) patients. MATERIALS AND METHODS: Thirty-six hips of 32 THRA patients were evaluated. The duration between THRA and DXA was from 1 year 7 months to 15 years. On transverse histogram, the periprosthetic bone density patterns were classified as 3 types;type I, rigid fixation in 17, type II, definite loosening in 8, and type III, partial loosening in 11 cases. Surgical findings, plain X-ray findnings and transverse histogram using DXA were correlated. RESULTS: Among 14 cases performing revision for acetabular prosthesis loosening, 5 cases revealed loosening of fernoral stems while 9 cases revealed rigid fixation of femoral stems. Sensitivity was 100% for either plain X-ray or DXA. Specificity was 88%, 77% for plain X-ray and DXA respectively. CONCLUSION: This preliminary study reveals that periprosthetic bone density pattern on transverse histogram on DXA may be useful in the evaluation of the loosening. However, further study will be needed for clinical application.
Acetabulum ; Arthroplasty, Replacement, Hip* ; Bone Density ; Hip ; Hip Prosthesis ; Humans ; Prosthesis Failure ; Sensitivity and Specificity

Recent technological advances have made magnetic resonance images (MR) of the knee a clinical reality. MR is rapidly replacing the conventional arthrography as the imaging modality of choice of the knee joints. To evaluate the diagnostic accuracy of MR in the internal derangement of the knee. MR findings of 244 menisci and 488 ligaments of 122 knees were correlated with those of subsequent arthroscopy or surgery in all cases. The sensitivity, specificity, and accuracy of MR diagnosis for the medial meniscus were 87%, 93%, 91%, for the lateral meniscus 91%, 95%, 93%, for the anterior cruciate ligament 80%, 97%, 92%, for the posterior cruciate ligamant 73%, 99%, 97%, for the medial collateral ligament 67%, 100%, 99%, for the lateral collateral ligament 100%, 100% and 100%. These results imply that MR is an excellent diagnostic modality in the preoperative evaluation of clinically suspected internal derangement of the knee.
Anterior Cruciate Ligament ; Arthrography ; Arthroscopy ; Collateral Ligaments ; Diagnosis ; Knee ; Knee Joint ; Lateral Ligament, Ankle ; Ligaments ; Magnetic Resonance Imaging* ; Menisci, Tibial ; Sensitivity and Specificity

Recent technological advances have made magnetic resonance images (MR) of the knee a clinical reality. MR is rapidly replacing the conventional arthrography as the imaging modality of choice of the knee joints. To evaluate the diagnostic accuracy of MR in the internal derangement of the knee. MR findings of 244 menisci and 488 ligaments of 122 knees were correlated with those of subsequent arthroscopy or surgery in all cases. The sensitivity, specificity, and accuracy of MR diagnosis for the medial meniscus were 87%, 93%, 91%, for the lateral meniscus 91%, 95%, 93%, for the anterior cruciate ligament 80%, 97%, 92%, for the posterior cruciate ligamant 73%, 99%, 97%, for the medial collateral ligament 67%, 100%, 99%, for the lateral collateral ligament 100%, 100% and 100%. These results imply that MR is an excellent diagnostic modality in the preoperative evaluation of clinically suspected internal derangement of the knee.
Anterior Cruciate Ligament ; Arthrography ; Arthroscopy ; Collateral Ligaments ; Diagnosis ; Knee ; Knee Joint ; Lateral Ligament, Ankle ; Ligaments ; Magnetic Resonance Imaging* ; Menisci, Tibial ; Sensitivity and Specificity

No abstract available.
Female ; Mammaplasty*

To evaluate the role of magnetic resonance(MR) imaging in the diagnosis of the discoid meniscus, the authors reviewed 31 cases of discoid menisci diagnosed by MR imaging among which 16 cases received arthroscopy. Using knee surface coil, sagittal T1, T2, & protein density images and coronal T1 weighted images were obtained with 18 cm FOV & 4mm/1 mm thickness/gap. A discoid meniscus was considered if three or more contiguous sagittal images demonstrated continuity of the meniscus between the anterior and posterior horns or the diameter of the mid-portion of the meniscus exceeded 15 mm on the coronal image. The authors also observed the associated abnormalities including tears of meniscus and ligament, meniscal cyst, and osteochondral defects. All discoid menisci were lateral menisci and torn discoid lateral menisci were present in 26 cases(83%). In two cases, tears of the contralateral medial meniscus were present. The tears of anterior and posterior cruciate ligaments, meniscal cyst, and osteochondral defects were present in 4, 2, 4, and 5 cases respectively. All collateral ligaments were intact. In conclusion MR imaging was useful for the detection of discoid meniscus and associated abnormalities.
Animals ; Arthroscopy ; Collateral Ligaments ; Diagnosis ; Horns ; Knee* ; Ligaments ; Magnetic Resonance Imaging* ; Menisci, Tibial ; Posterior Cruciate Ligament ; Tears