To find any specific radiologic findings of skeletal metastases from hepatocellular carcinoma, we analyzed plain radiographs(n=25), CT(n=16) and MRI(n=5)of 25 patients with metastatic bony lesions from hepatocellular carcinoma. Vertebrae(17/25) and rids(16/25)were most frequently involved and 16 cases showed multiple metastases. The size of the lesions was larger than 5cm in 17 cases. Plain radiographs showed osteolytic destruction(2/25). CT(n=16) showed osteolytic destruction with an isodense expansile mass in all cases. Focal low attenuations suggesting necrosis were found in 2 cases. Calcification within the mass was not detected. MRI(n=5) showed a slight hyperintense area on T1WI and a defimte hyperintense mass on T2WI. After gadopentetate dimeglumine enhancement. The mass showed irregular enhancement. We concluded that skeletal metastatic lesions from hepatocellular carcinoma showed relatively large osteolytic destruction accompanying soft tissue mass and minimum central necrosis.
Carcinoma, Hepatocellular* ; Gadolinium DTPA ; Humans ; Necrosis ; Neoplasm Metastasis*

Detection and evaluation of early soft tissue changes are important in rheumatoid arthritis or other jointdiseases. The most important factors for radiologic demonstration of soft tissue changes are resolving power andthe optimization of contrast differences between structures representing skin and subcutaneous tissue densities.Phantom study was done by using combination of immersion technique and mammography to get the most reliable methodfor improvement of soft tissue contrast without deterioration of resolution. Clinical application was also done in5 normal volunteers and 5 rheumatoid patients. The results indicate that soft tissue contrast, especially betwenskin and subcutaneous tissues can be significantly imporved with combination of immersion technique andmammography with 50% ethanol in both phantom and clinical study.
Arthritis, Rheumatoid ; Clinical Study ; Ethanol ; Healthy Volunteers ; Humans ; Immersion ; Mammography ; Radiography ; Skin ; Subcutaneous Tissue

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 assess the role of blood vessels in the formation of peritumoral abnormal signal intensity which exaggerates the size of malignant tumor on MR images. MATERIALS AND METHODS: We performed MR-microangiographic-pathologic correlation using implanted VX-2 carcinoma in 16 rabbit thighs 1-28 days after tumor implantation. The shape and distribution of abnormal vessels were analyzed on microangiography and on histologic examination in correlation with peritumoral abnormal signal intensity on MR images. RESULTS: Dilated peritumoral blood vessels gave rise to irregular, tortuous tumor vessels penetrated into the tumor. With the tumor growth, hypervascular tumor vessels in peritumoral area and central avascular areas were increased. These hypervascular areas on microangiography were corresponded with abnormal signal intensity on MR images. CONCLUSION: Hypervascularity could be a cause of peritumoral abnormal signal intensity which exaggerates the size of experimentally induced malignant musculoskeletal tumors on MR images.
Blood Vessels* ; Thigh

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: 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*

PURPOSE: To describe the MR characteristics of giant cell tumor of bone. MATERIALS AND METHODS: MR iraagings of 15 cases of pathologically proved giant cell tumor were retrospectively analyzed. Signal intensity and homogeneity, involvement of articular surface, low signal intensity rim around the tumor, cortical disruption and soft tissue involvement were evaluated. RESULTS:Tumor showed low signal intensity on T1 weighted images(93%), inhomogenous high signal on T2 or T2* weighted images(93%) and inhomogeneous enhancing pattern(88%). In 11 cases of giant cell tumor of long bones, all cases showed involvement of articular margin and 10 cases(90%) showed rim of low signal intensity between tumor and normal marrow. Disruption of cortical bone(25%) and soft tissue involevement(7%) were also demonstrated. CONCLUSION: We concluded that giant cell tumor showed characteristic MR findings could be helpful in making correct diagnosis.
Bone Marrow ; Diagnosis ; Giant Cell Tumor of Bone ; Giant Cell Tumors* ; Giant Cells* ; Retrospective Studies

To evaluate the radiographic characteristics of osteochondritis dissecans (OCD) and useful parameter for predicting mechanical stability, we retrospectively analysed 26 plain radiographic examinations and seven MR imagings in 28 cases of OCD in 24 patients. Typical radiologic findings were osteochondral defect with sclerotic rim of variable thickeness and osteochondral fragment. Sites of osteochondral defect were medial (35.9%) or lateral (32%) femoral chondyle and medial (7.1%) or lateral (25%) side of talar dome. Sclerotic rim was seen in 24 cases (85%) and osteochondral fragments including nine loose bodies were seen in 21 cases (75%). The size of osteochondral defect with unstable fragment (average 2.05cm) and loose body (2.04cm) in the knee joint were similar to, but statistically larger than that with stable fragment (1.35cm). All osteochondral defects were well visualized on MR images. Abnormalities of articular cartilage and effusion in the interface between the parent bone and fragment were seem in five cases of which there were confirmed three unstable cases arthroscopically. We conclude that size of defect may be a good parameter for predicting mechanical stability and MRI may be useful in the diagnosis of OCD and determining the methods of treatment.
Cartilage, Articular ; Diagnosis ; Humans ; Knee Joint ; Magnetic Resonance Imaging ; Osteochondritis Dissecans* ; Osteochondritis* ; Parents ; Retrospective Studies

This study was designed to evaluate the potential applicability of magnetic resonance imaging (MRI) for the diagnosis of acute renal vein thrombosis. Renal vein thrombosis was experimentally induced by surgical ligation of the left renal vein in a total of 21 rabbits. MRI was performed with a 0.5 Tesla superconductive magnetic system. Spin echo technique was used with varying TR and TE parameters. Spin echo images of the rabbit kidney were analysed for morphology and signal intensity. T1 and T2 relaxation times of the renal cortex and medulla were calculated from the images. After venous ligation, kidneys became enlarged. Low signal band along the outer medulla in T2 weighted images were characteristically shown from 1 hour to 3 days after ligation, Changes of cortex to medullar contrast (CMC) values were significant (p<0.05) in T1 - and T2- weighted images of the ligated side. T1 and T2 relaxation times were significantly prolonged (p<0.05) on the ligated side, both in the cortex and medulla from 1 hour to 2 weeks after the ligation, while T2 relaxation time on the contralateral side was significantly prolonged both in the cortex and medulla 2 weeks after venous ligation. The most useful MRI criteria for the diagnosis of renal vein thrombosis were enlarged renal size, and the low signal band along the outer medulla of ligated kidney. The relative intensity difference between cortex and medulla (CMC) in T1-and T2-weighted images, and T1 and T2 relaxation times were suggested to be the useful MR parameters for the diagnosis of acute renal vein thrombosis.
Diagnosis ; Kidney* ; Ligation* ; Magnetic Resonance Imaging* ; Rabbits ; Relaxation ; Renal Veins* ; Thrombosis

This study was designed to evaluate the potential applicability of magnetic resonance imaging (MRI) for the diagnosis of acute renal vein thrombosis. Renal vein thrombosis was experimentally induced by surgical ligation of the left renal vein in a total of 21 rabbits. MRI was performed with a 0.5 Tesla superconductive magnetic system. Spin echo technique was used with varying TR and TE parameters. Spin echo images of the rabbit kidney were analysed for morphology and signal intensity. T1 and T2 relaxation times of the renal cortex and medulla were calculated from the images. After venous ligation, kidneys became enlarged. Low signal band along the outer medulla in T2 weighted images were characteristically shown from 1 hour to 3 days after ligation, Changes of cortex to medullar contrast (CMC) values were significant (p<0.05) in T1 - and T2- weighted images of the ligated side. T1 and T2 relaxation times were significantly prolonged (p<0.05) on the ligated side, both in the cortex and medulla from 1 hour to 2 weeks after the ligation, while T2 relaxation time on the contralateral side was significantly prolonged both in the cortex and medulla 2 weeks after venous ligation. The most useful MRI criteria for the diagnosis of renal vein thrombosis were enlarged renal size, and the low signal band along the outer medulla of ligated kidney. The relative intensity difference between cortex and medulla (CMC) in T1-and T2-weighted images, and T1 and T2 relaxation times were suggested to be the useful MR parameters for the diagnosis of acute renal vein thrombosis.
Diagnosis ; Kidney* ; Ligation* ; Magnetic Resonance Imaging* ; Rabbits ; Relaxation ; Renal Veins* ; Thrombosis