Midsagittal Surface Research Articles

Preliminary evidence of links between ayahuasca use and the corpus callosum.

Recent research suggests that ayahuasca and its alkaloid-containing ingredients may be helpful in the treatment and prevention of certain movement and neurodegenerative disorders. However, such research is still in its infancy and more studies in normative samples seem necessary to explore effects of ayahuasca on clinically relevant brain structures, such as the corpus callosum. The purpose of the present study was to investigate links between ayahuasca use and callosal structure in a normative sample. Using structural imaging data from 22 ayahuasca users and 22 matched controls we compared the thickness of the corpus callosum between both groups at 100 equidistant points across the entire midsagittal surface. In addition, we investigated point-wise correlations between callosal thickness and the number of past ayahuasca sessions. The corpus callosum was significantly thicker within the isthmus in the ayahuasca group than in the control group. There was also a significant positive correlation between callosal thickness and the number of past ayahuasca sessions within the rostral body, albeit none of these effects survived corrections for multiple comparisons. No region was significantly thicker in the control than in the ayahuasca group, and no callosal region was negatively linked to ayahuasca use, even at uncorrected significance thresholds. This study provides preliminary evidence of links between ayahuasca use and the corpus callosum. However, future studies need to replicate these findings, preferably using larger sample sizes and ideally also utilizing longitudinal research designs, to draw any practical conclusion and offer implications for follow-up clinical research.

Corpus callosum injury after neurosurgical intervention for posthemorrhagic ventricular dilatation and association with neurodevelopmental outcome at 2 years.

Direct injury to the corpus callosum (CC) due to neurosurgical interventions in infants with posthemorrhagic ventricular dilatation (PHVD) has not been reported in the literature. The authors observed a subset of infants who had suffered penetrating CC injury after neurosurgical interventions for PHVD and hypothesized that this pattern of injury may result in suboptimal CC maturation and neurodevelopmental impairment. In this multicenter, retrospective, observational study, 100 preterm and 17 full-term infants with PHVD were included and compared with 23 preterm controls. Both neonatal and postneonatal brain MRI scans were assessed for injury, and measurements were performed on postneonatal MRI scans at 2 years' corrected age. Neurodevelopmental outcome was assessed at 2 years' corrected age. A total of 269 brain MRI scans of 140 infants were included. Of infants with PHVD, 48 (41%) had penetrating CC injury following neurosurgical interventions. The median (IQR) CC midsagittal surface area was smaller in infants with CC injury when compared with infants with PHVD who had intact CC and controls (190 mm2 [149-262 mm2] vs 268 mm2 [206-318 mm2] vs 289 mm2 [246-320 mm2], respectively; p < 0.001). In the univariate analysis, the area of the CC was associated with cognitive Z score (coefficient 0.009 [95% CI 0.005-0.012], p < 0.001) and motor Z score (coefficient 0.009 [95% CI 0.006-0.012], p < 0.001). In the multivariable model, CC injury was not independently associated with cognitive and motor Z score after adjusting for gestational age and presence of periventricular hemorrhagic infarction (coefficient 0.04 [95% CI -0.36 to 0.46] and -0.37 [95% CI -0.83 to 0.09], p = 0.7 and 0.1, respectively). CC injury was not uncommon following neurosurgical interventions for PHVD in both preterm and full-term infants. At the age of 2 years, the CC midsagittal surface area was smaller in infants with injury, but CC injury was not independently associated with cognitive and motor outcomes at 2 years' corrected age.

Corpus callosum morphology across the lifespan in baboons (Papio anubis): A cross-sectional study of relative mid-sagittal surface area and thickness

The corpus callosum enables integration and coordination of cognitive processing between the cerebral hemispheres. In the aging human brain, these functions are affected by progressive axon and myelin deteriorations, reflected as atrophy of the midsagittal corpus callosum in old age. In non-human primates, these degenerative processes are less pronounced as previous morphometric studies on capuchin monkey, rhesus monkeys, and chimpanzees do not find old-age callosal atrophy. In the present study, we extend these previous findings by studying callosal development of the olive baboon (Papio anubis) across the lifespan and compare it to chimpanzee and human data. For this purpose, total relative (to forebrain volume) midsagittal area, subsectional area, and regional thickness of the corpus callosum were assessed in 91 male and female baboons using non-invasive MRI-based morphometry. The studied age range was 2.5–26.6 years and lifespan trajectories were fitted using general additive modelling. Relative area of the total and anterior corpus callosum showed a positive linear trajectory. That is, both measures increased slowly but continuously from childhood into old age, and no decline was observed in old age. Thus, comparable with all other non-human primates studied to-date, baboons do not show callosal atrophy in old age. This observation lends supports to the notion that atrophy of the corpus callosum is a unique characteristic of human brain aging.

Lifespan trajectories of relative corpus callosum thickness: Regional differences and cognitive relevance

The cerebral hemispheres are specialized for different cognitive functions and receive divergent information from the sensory organs, so that the interaction between the hemispheres is a crucial aspect of perception and cognition. At the same time, the major fiber tract responsible for this interaction, the corpus callosum, shows a structural development across the lifespan which is over-proportional. That is, compared to changes in overall forebrain volume, the corpus callosum shows an accentuated growth during childhood, adolescence, and early adulthood, as well as pronounced decline in older age. However, this over-proportionality of growth and decline along with potential consequences for cognition, have been largely overlooked in empirical research. In the present study we systematically address the proportionality of callosal development in a large mixed cross-sectional and longitudinal sample (1867 datasets from 1014 unique participants), covering the human lifespan (age range 4–93 years), and examine the cognitive consequences of the observed changes. Relative corpus callosum thickness was measured at 60 segments along the midsagittal surface, and lifespan trajectories were clustered to identify callosal subsections of comparable lifespan development. While confirming the expected inverted u-shaped lifespan trajectories, we also found substantial regional variation. Compared with anterior clusters, the most posterior sections exhibited an accentuated growth during development which extends well into the third decade of life, and a protracted decline in older age which is delayed by about 10 years (starting mid to late 50s). We further showed that the observed longitudinal changes in relative thickness of the mid splenium significantly mediates age-related changes in tests assessing verbal knowledge and non-verbal visual-spatial abilities across the lifespan. In summary, we demonstrate that analyzing the proportionality of callosal growth and decline offers valuable insight into lifespan development of structural connectivity between the hemispheres, and suggests consequences for the cognitive development of perception and cognition.

Spatial possibilistic fuzzy C-Mean segmentation method integrated with brain Mid-Sagittal Surface information extracted by an evolutionary algorithm

Spatial possibilistic fuzzy C-Mean segmentation method integrated with brain Mid-Sagittal Surface information extracted by an evolutionary algorithm

Measurement of normal fetal cerebellar vermis at 24–32 weeks of gestation by transabdominal ultrasound and magnetic resonance imaging: A prospective comparative study

ObjectivesFetal cerebellar vermis may be assessed by ultrasound (US) or magnetic resonance imaging (MRI), and median-plane views are best for evaluation. The purpose of this study was to compare measurements of normal fetal vermis at 24–32 weeks of gestation obtained in median plane by transabdominal 2D-US, 3D-US, and MRI. MethodsA prospective study was conducted, examining normal singleton fetuses between 24 and 32 weeks of gestation. Within a 24-h period, median-plane views of posterior fossa were generated using 2D-US, 3D-US, and MRI. Measurements of anteroposterior (AP) diameter, craniocaudal (CC) diameter, mid-sagittal surface area, brainstem-vermis (BV) angle and brainstem-tentorium (BT) angle were obtained to compare these imaging modalities. ResultsA total of 180 fetuses were studied. Correlation among imaging methods was good, marked by the following intraclass correlation coefficients: AP diameter, 0.955; CC diameter, 0.956; mid-sagittal surface area, 0.982; BV angle, 0.810; and BT angle, 0.865 (p < 0.001). ConclusionsVisualization rates of MRI, 3D-US, and transabdominal 2D-US were decremental, MRI being superior in this regard. However, these three imaging modalities correlated well in measuring cerebellar vermis and its surroundings.

SIDEDNESS OF CAROTID ARTERY STENOSIS AND BRAIN VOLUME LOSS IN THE LEFT AND RIGHT HEMISPHERE: THE SMART-MR STUDY

Previous studies found an association between carotid stenosis degree and progression of brain atrophy, however no study reported on the relationship between sidedness of carotid stenosis and brain volume in the left and right hemispheres. We assessed the association between carotid stenosis side and changes in cerebral hemispheric volumes in patients with vascular disease. Within the SMART-MR study 1.5tesla MRI was performed in 1232 patients at baseline (mean age 58±10 years) and 663 after 4 years of follow-up. Carotid artery stenosis duplex measurements were performed at baseline and stenosis was defined at the cutpoint of 70%. Automated brain segmentation was used to quantify brain volumes and CSF. Volumes of the left and right hemispheres were calculated using the midsagittal surface. Using ANCOVA mean volume at baseline and mean change in volume between baseline and follow-up of the left and right hemisphere was estimated across 4 groups: no stenosis; left-sided stenosis only; right-sided stenosis only; bilateral stenosis adjusting for age and sex. In the total sample, brain volume (BV) of the left hemisphere was smaller than the right hemisphere (mean difference -1.06 %ICV; 95% CI -1.13 to -1.00) but this difference did not increase with age. Cross-sectionally, compared to participants without stenosis, those with left-sided stenosis had significantly smaller volume of the left but not the right hemisphere. However, right-sided stenosis was associated with smaller volumes of both hemispheres (Figure 1A). Similarly, in the longitudinal analysis a significant decrease in volume of both hemispheres was found in participants with right-sided stenosis, but not for left-sided stenosis (Figure 1B). In this population, as opposed to left-sided stenosis, right-sided stenosis results in brain volume reduction in both hemispheres. Studies should investigate whether other factors may explain this association or whether brain hemispheres have differential vulnerability to risk factors with aging. Left and right brain volumes in 4 groups: without carotid stenosis, left-sided stenosis, right-sided stenosis and bilateral stenosis. Bars represent mean (standard error) BV as % ICV. * p < 0.05 for difference in BV compared to corresponding hemisphere of the group without carotid stenosis (mean difference left hemisphere in left-sided stenosis -0.86 %lCV; 95% Cl -1.55 to -0.17, right hemisphere in right-sided stenosis -1.28 %ICV; 95% CI -1.90 to -0.67). Δp = 0.06 for difference in BV compared to the left hemisphere of the group without carotid stenosis (mean difference -0.60 %lCV; 95% Cl -1.22 to 0.03). lCV = intracranial volume. Longitudinal association between carotid stenosis groups and change in BV. Bars represent mean (standard error) change in BV as % ICV after a mean 3.9 years of follow-up. * p < 0.05 for decrease in BV compared to corresponding hemisphere of the group without carotid stenosis (mean difference left hemisphere in right-sided stenosis -0.45 %ICV; 95% CI -0.86 to -0.03, right hemisphere in right-sided stenosis -0.95 %ICV; 95%CI -1.37 to -0.53, left hemisphere in bilateral stenosis -0.81 %ICV; 95% CI -1.36 to -0.29, right hemisphere in bilateral stenosis -0.62 %ICV; 95% CI -1.16 to -0.09). ICV = intracranial volume.

Brain mid-sagittal surface extraction based on fractal analysis

In a normal human brain, inter-hemispheric fissure separates the brain into the left and the right hemispheres. In this paper, we model IF as a mid-sagittal surface on the input 3D brain MR image. For this purpose, we introduce a new method to extract MSS. In the proposed method, lacunarity is used to extract an initial symmetry plane, and then, fractal dimension is calculated in order to measure similarity degree between two brain hemispheres. Inside of each axial slice, a thin-plate spline surface is constructed based on the FD and intensity values, and a local optimization is applied to fit this TPS surface to the brain data using a robust least-median-of-squares estimator. Finally, MSS is modelled as a stack of the fitted TPSs, and the optimization is applied again in order to smooth the final MSS. MSS is the output of our method. The efficiency of the proposed method is evaluated using both simulated and real MR images and is compared to the state of the art. Our studies show that the proposed method discovers significant mid-sagittal surface with respect to the increased noise level and INU existence, in clinical images and pathological samples. This superiority is reasonable because of using FD and lacunarity being noise and INU independent and optimizing by TPS working locally.

Spatial Possibilistic Fuzzy C-Mean Segmentation Algorithm Integrated with Brain Mid-sagittal Surface Information

A normal human brain holds a high level of bilateral reflection symmetry. On the sagittal view, the brain can be separated into the left and the right hemispheres with approximately identical anatomical properties, so that symmetric mirror pixels have similar properties. As a result, the symmetry information can be used to enhance results of brain segmentation methods. In this paper, we introduced a new version of the Fuzzy C-Mean segmentation method, Symmetry Spatial Possibilistic FCM. SymSPFCM integrates symmetry information with SPFCM which is an extension of PFCM on 3D MR images, and uses the spatial information to calculate possibilistic values and fuzzy membership values. We added spatial and possibilistic information in order to solve the noise sensibility defect of FCM. To integrate the symmetry information, we first extracted the mid-sagittal surface using our proposed method. According to this method, inside each axial slice, a thin-plate spline surface was constructed and local optima were applied to fit this TPS surface to the brain data. Then, the symmetry degree of each symmetry pair was calculated. Finally, the membership values in SPFCM were updated based on the corresponding symmetric values. The efficiency of the proposed method, SymSPFCM, was evaluated using both simulated and real magnetic resonance images and was compared to the state-of-the-art methods. Our results showed images with different degrees of intensity non-uniformity and different levels of noise were segmented efficiently by the SymSPFCM.

Robust contour tracking in ultrasound tongue image sequences

ABSTRACTA new contour-tracking algorithm is presented for ultrasound tongue image sequences, which can follow the motion of tongue contours over long durations with good robustness. To cope with missing segments caused by noise, or by the tongue midsagittal surface being parallel to the direction of ultrasound wave propagation, active contours with a contour-similarity constraint are introduced, which can be used to provide ‘prior’ shape information. Also, in order to address accumulation of tracking errors over long sequences, we present an automatic re-initialization technique, based on the complex wavelet image similarity index. Experiments on synthetic data and on real 60 frame per second (fps) data from different subjects demonstrate that the proposed method gives good contour tracking for ultrasound image sequences even over durations of minutes, which can be useful in applications such as speech recognition where very long sequences must be analyzed in their entirety.

Automatic estimation of midline shift in patients with cerebral glioma based on enhanced voigt model and local symmetry.

Cerebral glioma is one of the most aggressive space-occupying diseases, which will exhibit midline shift (MLS) due to mass effect. MLS has been used as an important feature for evaluating the pathological severity and patients' survival possibility. Automatic quantification of MLS is challenging due to deformation, complex shape and complex grayscale distribution. An automatic method is proposed and validated to estimate MLS in patients with gliomas diagnosed using magnetic resonance imaging (MRI). The deformed midline is approximated by combining mechanical model and local symmetry. An enhanced Voigt model which takes into account the size and spatial information of lesion is devised to predict the deformed midline. A composite local symmetry combining local intensity symmetry and local intensity gradient symmetry is proposed to refine the predicted midline within a local window whose size is determined according to the pinhole camera model. To enhance the MLS accuracy, the axial slice with maximum MSL from each volumetric data has been interpolated from a spatial resolution of 1mm to 0.33mm. The proposed method has been validated on 30 publicly available clinical head MRI scans presenting with MLS. It delineates the deformed midline with maximum MLS and yields a mean difference of 0.61±0.27mm, and average maximum difference of 1.89±1.18mm from the ground truth. Experiments show that the proposed method will yield better accuracy with the geometric center of pathology being the geometric center of tumor and the pathological region being the whole lesion. It has also been shown that the proposed composite local symmetry achieves significantly higher accuracy than the traditional local intensity symmetry and the local intensity gradient symmetry. To the best of our knowledge, for delineation of deformed midline, this is the first report on both quantification of gliomas and from MRI, which hopefully will provide valuable information for diagnosis and therapy. The study suggests that the size of the whole lesion and the location of tumor (instead of edema or the sum of edema and tumor) are more appropriate to determine the extent of deformation. Composite local symmetry is recommended to represent the local symmetry around the deformed midline. The proposed method could be potentially used to quantify the severity of patients with cerebral gliomas and other brain pathology, as well as to approximate midsagittal surface for brain quantification.

Changes of the corpus callosum in the parkinsonism

The corpus callosum (CC) is the largest white-matter fibre tract in the brain that plays essential role in communicating sensory, motor and cognitive information between the two cerebral hemispheres. Corpus callosum area has been examined extensively in neurodegenerative diseases as a marker for cortical pathology and for differential diagnosis. However, there have been very few studies that examined CC area in Parkinson’s disease (PD). In the present study, we aimed to determine whether there are alterations in the CC of PD. The study included 20 (9 females and 11 males) adult controls and 20 (8 females and 12 males) patients with PD. Structural MRI was done to both patients and controls. Dicom images were analysed using ImageJ software. Midsagittal surface area of the corpus callosum and intracranial cavity were measured using the planimetry technique. The projection area fraction (PAF) of the CC was measured in the midsagittal section of magnetic resonance images.The mean of midsagittal surface area of the corpus callosum and intracranial cavity in healthy subjects were 5.93±0.75 cm 2 and 147.20±9.11 cm 2 , respectively, and were 6.26±0.75 cm 2 and 151.10±13.68 cm 2 for patients. The mean of the projection area fraction (PAF) for controls and patients were 4.04 cm 2 ± 0.54 and 4.16 cm 2 ±0.53.There were no statistical differences between groups regarding the midsagittal surface area of the corpus callosum, intracranial cavity and PAF (p≤0.05). In the light of the literature there are few studies for the assessment of the CC in PD, the obtained data of those studies didn’t show statistical significant differences between groups and gender. We conclude that the patient with PD do not have CC atrophy in contrast to other neurodegenerative diseases.

Automatic Extraction of the Midsagittal Surface from Brain MR Images using the Kullback–Leibler Measure

The midsagittal surface separates the two hemispheres of the cerebrum. This surface is often typified as a geometrical plane: the midsagittal plane. However, in subjects with a considerable amount of naturally occurring brain torque, the midsagittal surface deviates to a large extent from a plane. In the present study, an automated method to extract the midsagittal surface is proposed, evaluated on a large dataset, and compared to a conventional midsagittal plane representation. The midsagittal plane was extracted from MR images with a technique based on the Kullback-Leibler measure. This plane was used to initialize a surface, that was deformed to represent the midsagittal surface. One hundred subjects were selected from the SMART-MR study: fifty subjects with brain torque and fifty random subjects. Manual delineations of the midsagittal surface were used for evaluation. The extracted midsagittal planes and surfaces were compared to the manual delineations by assessing the absolute volume of misclassified cerebrum tissue. The midsagittal surface resulted in significantly better separations of the hemispheres. In the randomly selected subjects, the error reduced from 2.71 ± 1.05 ml to 2.20 ± 0.66 ml and in subjects with brain torque from 4.85±2.79 ml to 2.23±0.77 ml, with improvements up to 16.6 ml in individual subjects with marked brain torque.

Long anterior mandibular tooth roots in Neanderthals are not the result of their large jaws

Tooth root length has been shown to taxonomically distinguish Neanderthals from modern humans. However, this may result from differences in jaw size between both taxa, although most previous studies have revealed a very low or non-existent correlation between tooth size and jaw size in recent modern humans. We therefore investigated, within a broader taxonomical frame, to what extent measurements on the anterior tooth roots and the symphyseal region covary.Our samples comprise permanent mandibular incisors and canines from Mauer, Neanderthals, and extant and fossil modern humans sensu lato. Using micro-computed tomography, we took linear and cross-sectional surface area measurements of the roots and the symphyseal region and calculated the root volume. We also measured 3D landmarks to quantify the overall size of the mandible using centroid size. Furthermore, we analyzed the relationship between root size and symphyseal shape, based on Procrustes shape variables of semi-landmarks along the symphyseal outline.Our results show that Neanderthals have significantly larger anterior tooth roots than recent modern humans in terms of root length, mid-sagittal surface area and volume, even after correction for mandibular size. In contrast, symphyseal height and width do not differ significantly between both taxa, whereas, without scaling, the mid-sagittal symphyseal surface area and the centroid size of the mandible do differ. Importantly, no significant correlation was found between any of the root and symphyseal measurements after correction for overall mandibular size. The shape analyses revealed that Neanderthals have a vertical symphyseal profile with an evenly-thick symphysis, whereas recent modern humans display an unevenly-thick symphysis, comprising a pronounced incurvatio mandibularis and a bony chin. These results suggest a negative evolutionary allometry for the recent modern human anterior root size. Therefore, root length and other root dimensions can be considered taxonomically relevant for distinguishing Neanderthals from modern humans.

Social communication in young children with traumatic brain injury: Relations with corpus callosum morphometry

The purpose of the present investigation was to characterize the relations of specific social communication behaviors, including joint attention, gestures, and verbalization, with surface area of midsagittal corpus callosum (CC) subregions in children who sustained traumatic brain injury (TBI) before 7 years of age. Participants sustained mild (n=10) or moderate–severe (n=26) noninflicted TBI. The mean age at injury was 33.6 months; mean age at MRI was 44.4 months. The CC was divided into seven subregions. Relative to young children with mild TBI, those with moderate–severe TBI had smaller surface area of the isthmus. A semi-structured sequence of social interactions between the child and an examiner was videotaped and coded for specific social initiation and response behaviors. Social responses were similar across severity groups. Even though the complexity of their language was similar, children with moderate–severe TBI used more gestures than those with mild TBI to initiate social overtures; this may indicate a developmental lag or deficit as the use of gestural communication typically diminishes after age 2. After controlling for age at scan and for total brain volume, the correlation of social interaction response and initiation scores with the midsagittal surface area of the CC regions was examined. For the total group, responding to a social overture using joint attention was significantly and positively correlated with surface area of all regions, except the rostrum. Initiating joint attention was specifically and negatively correlated with surface area of the anterior midbody. Use of gestures to initiate a social interaction correlated significantly and positively with surface area of the anterior and posterior midbody. Social response and initiation behaviors were selectively related to regional callosal surface areas in young children with TBI. Specific brainbehavior relations indicate early regional specialization of anterior and posterior CC for social communication.

Explaining Function with Anatomy: Language Lateralization and Corpus Callosum Size

The anatomy of the corpus callosum (CC) has been advocated as a potential marker for functional lateralization because its size is supposedly proportional to the number of fibers connecting the hemispheres. Previous morphometric studies of this relationship have compared CC size in groups of subjects who are more or less likely to show differences in their lateralization (e.g., left vs right handers). The findings, however, have been inconsistent, and to our knowledge, no previous study has directly compared CC size with lateralization assessed by functional imaging data. We therefore combined anatomical measurements of CC size with left versus right hemisphere language activation in 74 normal subjects. After controlling for perceptual and motor output effects, as well as for global white-matter volume, handedness, gender and age, we found that subjects who had a larger CC showed more left lateralization for language in posterior temporal and inferior frontal regions. Examination of these effects revealed that, as CC size increased, stronger lateralization resulted from more left hemisphere activation in both regions as well as reduced right hemisphere activation in the posterior temporal region. Our observations provide the first clear evidence in normal subjects that the midsagittal surface area of the CC contributes to the degree to which language is functionally lateralized. We discuss the complex interhemispheric processes that might underlie this effect.

Compensatory responses to unexpected jaw loading during speech observed with magnetometry

Observations were made of articulator and formant trajectories during speech perturbed by unexpected mechanical loads applied to the jaw. Subjects produced multiple repetitions of the phrase ‘‘see X avis,’’ where X was one of ‘‘raw,’’ ‘‘rob’’ or ‘‘rod.’’ Perturbation forces were applied using a jaw-coupled robot, and triggered using a thresholding criterion applied to real-time tracking of the initial low to high transition in the first formant. Perturbations were delivered one out of every five repetitions, selected at random, with half applied upwards and half downwards, and forces sustained throughout the remainder of the utterance. Three EMMA sensors located on the anterior midsagittal surface of the tongue in addition to lower mandibular and upper lip sensors were used to track articulator positions. Audio and surface EMG (masseter, ABD, and OOS) were collected concurrently. Formants show initial deviation from control trajectories and then recovery that begins approximately 75 ms after the onset of perturbation. Compensation in most instances is nearly complete, even though jaw position does not recover its unperturbed trajectory. Perturbed tongue sensor trajectories are strongly distinguished by coda type, but show a pattern converging on the unperturbed tongue shape consistent with the tongue’s presumed role in effecting formant recovery.

Preoperative Visualization of the Artery of Adamkiewicz by Intra-Arterial CT Angiography

CT and MR angiographies have been reported to visualize the artery of Adamkiewicz (AKA) noninvasively to prevent spinal cord ischemia in surgery of thoracic descending aortic aneurysms. The purpose of this work was to compare the usefulness of CT angiography (CTA) with intra-arterial contrast injection (IACTA) with that of conventional CTA with intravenous contrast injection (IVCTA). We enrolled 32 consecutive patients with thoracic or thoracoabdominal aortic aneurysms who were scheduled for surgical repair or endovascular stent-graft treatment. All of the CTA images were obtained using a 16-detector row CT scanner and 100 mL of contrast material (370 mg/mL) injected at a rate of 5 mL/s. Contrast was injected via the antecubital veins of 15 patients and via a pig-tail catheter placed at the proximal portion of the descending aorta in 17 patients who underwent IVCTA and IACTA, respectively. Two datasets were reconstructed from 2 consecutive scans. The AKA was identified as a characteristic hairpin curved vessel in the anterior midsagittal surface of the spine and by the absence of further enhancement in the second rather than in the first phase. Continuity between the AKA and aorta was confirmed when the vessel could be traced continuously by paging the oblique coronal multiplanar reconstruction or original axial images. Intra-arterial contrast injection was significantly more sensitive in identifying the AKA than IVCTA: 16 (94.1%) of 17 versus 9 (60.0%) of 15 (P = .033). Continuity between the AKA and aorta through intercostal or lumbar artery was confirmed in 14 (87.5%) of 16 and 5 (55.6%) of 9 of the IACTA and IVCTA groups, respectively. Intra-arterial contrast injection detected the AKA at a high rate and verified continuity from the aorta to the AKA.

Craniofacial Morphology in Muenke Syndrome

The purpose of this study was to test whether the severity of the cranial phenotype in Muenke syndrome infants with unicoronal synostosis is greater than in infants with nonsyndromic unicoronal synostosis. A total of 23 infants were included in the study. All infants included in the study had a computed tomography (CT)-verified synostosis of the coronal suture. The patients were either placed into the "Muenke" group (n=11) or the "non-Muenke" control group (n=12) on the basis of a test for the P250R mutation in the FGFR3 gene. On the basis of CT scans, a three-dimensional surface model corresponding to bone was created for each individual. The sutures were inspected for synostosis, and the degree of synostosis was assessed. Increased digital markings were recorded for both groups. Craniofacial morphology was assessed quantitatively using bony landmarks and recording of the midsagittal surface of the calvaria, cranial base, and maxillary complex. Increased digital markings were more severe posteriorly in Muenke patients than in non-Muenke patients. The Muenke patients with unilateral coronal synostosis showed a somewhat more severe asymmetry in the anterior part of the skull than the non-Muenke patients. The study indicates differences with regard to severity of increased digital markings and craniofacial asymmetry between the infants with Muenke syndrome and the infants with nonsyndromic unilateral coronal synostosis.

Cerebellar vermis morphology in children with spina bifida and Chiari type II malformation

Posterior fossa size and cerebellar weight and volume are reduced in Chiari type II malformation (CII). This is assumed to affect the cerebellum uniformly. We quantified the presumed reduction in vermis size on magnetic resonance imaging (MRI). A midsagittal brain MRI slice was selected from each of 68 participants with CII (mean age 13 years). Control participants were 28 typically developing children (mean age 14.1 years). Midsagittal surface areas occupied by the intracranial fossa, posterior fossa, vermis, and its lobules were measured. Mean posterior fossa area was significantly smaller (P<0.003), although mean vermis area was significantly larger (P<0.0001), in participants with CII than in control participants. This expansion involved vermis lobules I-V and VI-VII areas (P<0.0001). The midsagittal vermis was expanded and not reduced in size in participants with CII. This is attributed to compressive displacement of midline structures within the confines of a small posterior fossa.