| The calcarine sulcus is an important anatomical reference and forms the basis for many clinical diagnoses, surgery and functional studies in the medial surface of the occipital lobe. However, the data of its structural characteristics in vivo are very deficient. Using a parametric ribbon method, in this study we studied the size and morphology of the calcarine sulcus in 60 normal Chinese adult brains using magnetic resonance imaging (MRI). After measuring the parameters of calcarine sulcus, the lateralization and gender effects are also analyzed. The accessory occipital ventricles were also distinguished. This in vivo study provides an anatomical basis for appropriate clinical diagnoses and surgery, and may facilitate future functional brain studies. The study was divided into three parts. The abstracts were as follows:Part 1:Morphology and size and lateriality effect of the calcarine sulcus in female adultPurpose: To study the size and morphology and laterality effect of normal female calcarine sulcus and provide a structural basis for appropriate clinical diagnoses, surgery and future functional brain studies.Methods:High-resolution and transverse MR images were obtained from 30 female volunteers. Brainvisa software was used to reconstruct the calcarine sulcus and measure its average length, depth and width automatically. After observing the morphology and measuring the parameters of calcarine sulcus, SPSS 17.0 was used for Windows to analyze the laterality effect.Results:By analyzing the morphology of the posterior calcarine sulcus in the median sagittal plane, we detected a dichotomous proportions of bifurcation (43.33%) and no-bifurcation (56.67%) patterns. There were five specific sub-patterns observed in the no-bifurcation calcarine sulci. These included single peak (16.67%), line (15.00%), S-shape (10.00%), double peak (8.33%) and others (6.67%) shapes. Based on the location of the posterior calcarine sulcus, three types of patterns were identified in the median sagittal plane-inferior (61.67%), middle (30.00%) and superior (8.33%). The accessory occipital ventricles were distinguished in 23 of the 60 hemispheres (38.33%). Before spatial normalization, using the raw calcarine sulcal parameters, a significant rightward asymmetry was found in the depth of female calcarine sulcus (t=4.66, p≤0.0001). After spatial normalization, no significant laterality were found in the calcarine sulcal parameters of female.Conclusion:Great difference of depth between left and right calcarine sulcus of female was found. Three-dimensional reconstruction was an effective method in study the morphology and the measurement of calcarine sulcus.Part 2:Morphology and size and lateriality effect of the calcarine sulcus in male adultPurpose: To study the size and morphology and laterality effect of normal male calcarine sulcus and provide an anatomical basis for appropriate clinical diagnoses, surgery and future functional brain studies.Methods:High-resolution and transverse MR images were obtained from 30 male volunteers. Brainvisa software was used to reconstruct the calcarine sulcus and measure its average length, depth and width automatically. After observing the morphology and measuring the parameters of calcarine sulcus, SPSS 17.0 was used for Windows to analyze the laterality effect.Results:By analyzing the morphology of the posterior calcarine sulcus in the median sagittal plane, we detected a dichotomous proportions of bifurcation (46.67%) and no-bifurcation (53.33%) patterns. There were five specific sub-patterns observed in the no-bifurcation calcarine sulci. These included single peak (11.67%), line (16.67%), S-shape (10.00%), double peak (10.00%) and others (5.00%) shapes. Based on the location of the posterior calcarine sulcus, three types of patterns were identified in the median sagittal plane-inferior (70.00%), middle (21.67%) and superior (8.33%). The accessory occipital ventricles were distinguished in 22of the 60 hemispheres (36.67%). No significant asymmetry was found in the raw or the normalized calcarine sulcal parameters of male.Conclusion:No significant asymmetry was found in the raw or the normalized calcarine sulcal parameters of male. Three-dimensional reconstruction was an effective method in study the morphology and the measurement of calcarine sulcus.Part3:Gender effect on the size and morphology of calcarine sulcusPurpose:To study the gender effect on the size and morphology of calcarine sulcus and provide an basis for future functional brain studies and clinical diseases.Methods:High-resolution and transverse MR images were obtained from 60 volunteers (30 males,30 females). Brainvisa software was used to reconstruct the calcarine sulcus and measure its average length, depth and width automatically. After observing the morphology and measuring the parameters of calcarine sulcus, SPSS 17.0 was used for Windows to analyze the gender effect.Results:No significant gender differences were found in the morphology patterns or in the location patterns. Before normalization, not only the size of calcarine sulcus was relatively larger in males than in females, but also the difference in the depth of left calcarine sulcus was significant (t=3.06, p=0.003). No significant gender differences were found after normalization which removed the gross differences in brain size.Conclusion:The significant gender effect which detected in the left calcarine sulcus disappeared after removed the gross difference in brain size. This indicate that most of the gender differences we detected were due to individual differences in cerebral volume.Conclusion and SignificanceUsing a parametric ribbon method, we detected the morphology and size of calcarine sulcus after 3D reconstruction of MRI and the effect of lateralization and gender on sulcal patterns. Compared with prior postmortem studies, this vivo study provides useful stereotaxic information for clinical diagnoses, surgery and functional studies. However, given the tight age-range of our subjects, no age-related trend of calcarine sulcus was discovered. Further studies should be conducted to explore the relationships between the different morphological patterns and size of the calcarine sulcus and the function of vision.
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