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Objective To discuss the imaging features of intracranial chondromas at unusual locations.Methods Six patients with intracranial chondroma conformed by surgery and histopathology (3 lesions located at the convexity,and the others located at the falx cerebri),admitted to our hospital from February 2010 to April 2011,were chosen in our study; their imaging features were retrospectively analyzed.Results CT scans showed obvious calcification and clear borders of the tumors in 5 patients,and the mixed attenuation and adjacent bone invasion in 2 patients.MRI scans demonstrated that the parenchyma of the tumors had hyperintense on T1WI and hyperintense on T2WI,and the calcified elements of the tumors had hyperintense on TlW1 and hypointensity on T2WI; tumor bleeding lesions had hyperintense on T2WI and hypointensity on T1WI; the characteristic sign,"foamy sign",was found in 3 patients.Obvious inhomogeneous enhancement was observed in one and slight enhancement in 3 patients,while other two patients showed no enhancement.Conclusion Intracranial chondromas arising from the unusual locations is often misdiagnosed; combined imaging findings,including giant mass,and globular or diffuse calcification,can be helpful in the preoperative diagnosis.
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Objective To establish a method for precise localization of the boundaries of the glial scars in chronic spinal cord injury for their complete resection to provide the experimental basis for neural stem cell transplantation studies. Methods Chronic spinal cord injury was induced in beagl edogs via partial transections of the thoracic segment of the spinal cord. Three months after the operation, with the posterior-medial midpoint of the inferior edge of the first vertebral plate above the bony window defined as the point-of-origin of a 3-dimensional space, the distances from the superior and inferior margins of the injured spinal segment to the point-of-origin were measured on anteroposterior magneti cresonance images (MRI). B-mode ultrasound was used to detect the signal variations in the spinal cord .Immunohistochemistry was performed on the longitudinal sections of the spinal cord for microscopi cmeasurement of the glial fiber lengths in comparison with the length determined by MRl. Results MRI defined a greater length (14.7±0.94 mm) of glial scars with abnormal signals than the actually injured length (10 mm). Ultrasound detected obvious signal changes in the injured spinal cord with distinct boundaries of the injuries. The glial scar length in the spinal cord defined pathologically (18.6± 1.19 mm) exceeded that defined by anteroposterior MRI scanning. Conclusions Anteroposterior MRI scanning combined with stereotactic localization allows approximate determination of the glial scar boundary in the injured spinal cord, and the discrepancies can be adjusted according to the result of pathological measurements. Ultrasonic inspection helps detect the residue scar tissues aRer surgica lresection to ensure complete glial scar resection.
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<p><b>OBJECTIVE</b>To evaluate the characteristics of MR imaging of hepatic lesions using measurement of apparent diffusion coefficient (ADC) value of hepatic lesions on diffusion weighted imaging.</p><p><b>METHODS</b>MR diffusion weighted images were obtained in patients with 97 hepatic lesions (22 hepatocellular carcinomas, 21 metastatic tumors, 28 hemangiomas, 26 cysts). ADC values were evaluated with different sequences. The ADC ratio of lesion/liver was estimated.</p><p><b>RESULTS</b>Average ADC values of hepatic lesions were as follows: carcinomas (0.91 +/- 0.07) x 10(-3) mm(2)/s, metastatic tumors (1.13 +/- 0.27) x 10(-3) mm(2)/s, cavernous hemangiomas (1.94 +/- 0.37) x 10(-3) mm(2)/s, cysts (3.26 +/- 0.30) x 10(-3) mm(2)/s. The ADC ratio of lesion/liver was significantly different between primary carcinomas and metastatic tumors (P < 0.05).</p><p><b>CONCLUSION</b>Quantitative study in hepatic lesions using ADC values and the ADC ratio of lesion/liver, would improve the accuracy in diagnosing hepatic lesions.</p>