Résumé
Objective To explore the significance and application of the angle between the canthomeatal line (CML) and the anterior commissure-posterior commissure (AC-PC) line in the sagittal plane projection in stereotactic neurosurgery.Methods Quantitative MRI was performed in a cross-sectional analysis of 120 normal volunteers from south China; the angle between the canthomeatal line and the AC-PC line in the sagittal plane projection,the length of the intercommissure line,and the vertical distance from external auditory canal midpoint to the AC-PC plane were measured and matched for age and gender.Results The average angle between the CML and the AC-PC line in the sagittal plane projection of all South China adult brains is (12.03±1.11)°,which is (12.17±1.06)° in male and (11.89±1.14)° in female.The average length of AC-PC line is (23.74±0.95) mm,which is (24.35±0.64) mm in male and (23.14±0.95) mm in female.The average length of the vertical distance from external auditory canal midpoint to the AC-PC plane of all is (48.69±4.03) mm,which is (49.57±3.10) mm in male and (47.82±4.61) mm in female.Clinical validation showed that the deviation angle to the actual AC-PC plane was (1.56±0.63)°.Conclusion The angle formed by CML and the AC-PC plane is stable in adults of different gender and ages; taking CML as a baseline,the surface projection of AC-PC line can be drew with the angle and the vertical distance,and then,the AC-PC plane by adjusting the directional headstock can be obtained with high accuracy,repeatability and maneuverability; therefore,these data can be used as a valuable reference of adult brain structure of Han nationality in South China.
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Objective To study the clinical and MR imaging features of patients with Joubert syndrome to improve the understanding of this disorder and the diagnosis accuracy.Methods A retrospective study of clinical and MR imaging data was performed in 3 pediatric patients had definite diagnosis of Joubert syndrome; and a comprehensive review of literature was presented.Results All 3 patients showed typical manifestations of complex brainstem malformations on MR imaging which comprised the "molar tooth sign" on midbrain level,"thin median cleft" separating cerebellar hemispheres and "bat wing" appearance of the fourth ventricle due to the cerebellar vermis hypoplasia.Clinically,hypotonia,intermittent irregular breathing pattern (with apnea in 1 patient) and developmental delay/mental retardation in infancy in all 3 patients and abnormal eye movements (episodic deviation to lateral extremes of gaze) in 1 patient were noted.Conclusion Joubert syndrome is characterized on MR imaging,but clinical data is necessary for an exact diagnosis; differentiation should be made with the other disorders due to the hypoplasia of cerebellar vermis.
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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.