Skull Base Angle Morphometry in South Indian Population with Review on Terminology

Introduction Basal angle, Boogaard’s angle, and clival angle are frequently used in diagnosing the craniometric angle malformations either on radiography or now more on MRI. But anatomic and clinical studies have used varied terms for these parameters. We aimed to look for these parameters among a normal south Indian adult population to standardize the measurements and their terminology. Materials and Methods One hundred MRI images (50 males and 50 female) were studied retrospectively. MRI images that were reported as normal by neuroradiologist were taken up for the study. Mean and the standard deviation of males and females were calculated for basal angle, Boogaard’s angle, and clival angle, separately. Unpaired t-test was used to analyze the significant difference (p < 0.05) between the genders. The intraclass coefficient correlation was used to analyze the interobserver variability. Results The mean value of basal angle in males and females are 113°and 114°, respectively. The mean value of Boogaard’s angle in males and females are 120°and 121°, respectively. The mean value of clival angle in males and females are 157°and 155°, respectively. There was no statistically significant difference (p > 0.05) between males and females in all three angles. Conclusion Knowledge about the normal angles will be an important tool in understanding the normal and abnormal skull base. Since the type of skull varies in accordance with race, the normal craniometric angle also varies in accordance with race. The present study tried to standardize the parameters of normal skull base angles for appropriate correction of the anomalies and uniform usage of terminology.

Clival canal Angle and Basal Angle in Nepalese Population- A Computed Tomography Based Study

Background: Clival canal angle is an angle formed by the clivus and the posterior longitudinal ligament of the cervical spine and Welcher basal angle formed between the line joining the nasion to tuberculumSella and the line joining the tuberculum sellae to basion along the plane of clivus. With the aim to review the normal distribution of clival canal angle and basal angle in the Nepalese population this study was performed. Methods and materials: This is a cross-sectional analytical study with non- probability consecutive sampling technique done over the duration of 3 months. A reconstructed image of a bone window in the midsagittal plane was selected and measurement of the angles was done in CT console. Results: There was a total of 60 patients in this study with male predominance (figure 3). The mean age of the population was 49.8 (SD 18.8) years. The clival canal angle reference range was 130.8 to 168.8 degrees with a mean 149.8(SD 9.5) degree. Similarly, the reference range of Welcher basal angle in the study population was 115.49 to 140.29 degree with a mean of 127.89(SD: 6.4) degrees. Conclusion: The mean clival canal angle in the Nepalese population is 149.8 (SD: 9.5) degrees and the mean basal angle is 127.89(SD: 6.4) degree.

A new deep-sea scalpelliform barnacle, Vulcanolepas buckeridgei sp. nov. (Eolepadidae: Neolepadinae) from hydrothermal vents in the Lau Basin

The present study describes a new species of Vulcanolepas from the Lau Basin in the South Pacific. The basal angle of the tergum of Vulcanolepas buckeridgei sp. nov. is elevated from the capitular-peduncular margin at ~1/6 of the capitular height. The mandibles of V. buckeridgei sp. nov. are tridentoid; the cutting margins of the second and third teeth are long and each tooth possesses 18–20 sharp spines. The proximal segments of the anterior and posterior rami of cirrus I are protuberant and with dense, simple setae. DNA barcode sequences of Vulcanolepas buckeridgei sp. nov. are similar to Vulcanolepas sp. 1 collected from the Lau Basin (Herrera et al. 2015). Vulcanolepas buckeridgei is morphologically similar to Vulcanolepas ‘Lau A’ collected in the Lau Basin (Southward & Newman 1998). This suggests that Vulcanolepas buckeridgei sp. nov. is widespread in the Lau Basin.

Cranio-vertebral transition assessment by magnetic resonance imaging in a sample of a northeast Brazilian population

ABSTRACT Platybasia and basilar invagination are important alterations of the cranial-vertebral transition. Neuroimaging-based platybasia parameters include the Welcker basal angle, distance between the apex of the odontoid and Chamberlain’s line, and the clivus-canal angle. This study aimed to measure and correlate these parameters in a sample from northeast Brazil. Methods Cross-sectional analysis of craniometric parameters from individuals submitted to magnetic resonance at an outpatient imaging center between 2011 and 2012. Results Of 181 analyzed cases, the Welcker basal angle averaged 128.96º (SD 6.51), median distance between apex of the odontoid and Chamberlain’s line was 2.27 mm (IQR -1.23–4.47) and the median clivus-canal angle was 150.5º (IQR 143.2–157.3). The Welcker basal angle was inversely correlated to the clivus-canal angle, and correlated to the distance between the apex of the odontoid and Chamberlain’s line. Conclusion There was a tendency to platibasia, basilar invagination and narrowing of the cranio-vertebral transition.

Computed tomography evaluation of the normal craniocervical junction craniometry in 100 asymptomatic patients

OBJECT Most of the craniometric relationships of the normal craniocervical junction (CCJ), especially those related to angular craniometry, are still poorly studied and based on measurements taken from simple plain radiographs. In this study, the authors performed a craniometric evaluation of the CCJ in a population without known CCJ anomalies. The purpose of the study was to evaluate the normal CCJ craniometry based on measurements obtained from CT scans. METHOD The authors analyzed 100 consecutive CCJ CT scans obtained in adult patients who were admitted at their tertiary hospital for treatment of non-CCJ conditions between 2010 and 2012. A total of 17 craniometrical measurements were performed, including the relation of the odontoid with the cranial base, the atlantodental interval (ADI), the clivus length, the clivus-canal angle (CCA)—the angle formed by the clivus and the upper cervical spine, and the basal angle. RESULTS The mean age of the 100 patients was 50.6 years, and the group included 52 men (52%) and 48 women (48%). In 5 patients (5%), the tip of the odontoid process was more than 2 mm above the Chamberlain line, and in one of these 5 patients (1% of the study group). it was more than 5 mm above it. One patient had a Grabb-Oakes measurement above 9 mm (suggesting ventral cervicomedullary encroachment). The mean ADI value was 1.1 mm. The thickness of the external occipital protuberance ranged from 7.42 to 22.36 mm. The mean clivus length was 44.74 mm, the mean CCA was 153.68° (range 132.32°–173.95°), and the mean basal angle was 113.73° (ranging from 97.06°–133.26°). CONCLUSIONS The data obtained in this study can be useful for evaluating anomalies of the CCJ in comparison with normal parameters, potentially improving the diagnostic criteria of these anomalies. When evaluating CCJ malformations, one should take into account the normal ranges based on CT scans, with more precise bone landmarks, instead of those obtained from simple plain radiographs.

Abstract 13804: Correlation between Electrocardiographic Features and Local Activation Pattern in Arrhythmogenic Right Ventricular Dysplasia

Background: Depolarization abnormalities in the terminal portion of the QRS are frequently seen in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C). The purpose of this study was to correlate the electroanatomic activation pattern of the RV endocardium and epicardium to the surface ECG. Methods: Thirty consecutive ARVD/C patients (Mean age 33.1 +/- 11.2 years, 16 (53%) men) underwent detailed endocardial and epicardial electroanatomical mapping (EAM). Local sinus rhythm activation was annotated at the sharpest intrinsic deflection of the bipolar electrogram, including late potentials. ECG features were classified into 5 major patterns; 1. Normal QRS (12 patients) 2. Epsilon wave (5 patients) 3. Incomplete RBBB (5 patients) 4. Atypical complete RBBB (6 patients) and 5. Prolonged terminal activation duration (TAD) (2 patients) Results: The earliest endocardial and epicardial RV activation occurred on the mid anteroseptal wall on all ECG patterns. Figure 1 represented activation area (purple) after the QRS or during the delayed depolarization phase. Nearly all endocardial and epicardial RV was activated well within the QRS duration in patients with normal QRS but was activated during R’ in patients with CRBBB. The delayed activation during Epsilon wave consistently occurred in basal anterior wall and basal angle of RV. In patients with TAD, the activation of RVOT and basal angle RV represented slurred S wave. Conclusion: ECG features in ARVD/C are correlated with late activation in specific regions of RV and total endocardial activation time. The delay activation of basal anterior wall and basal angle of RV represents the Epsilon wave in the right precordial ECG.