Are coding systems of frontal sinuses anatomically reliable? A study of correlation among morphological and metrical features.

Frontal sinuses are of special interest for personal identification thanks to their high variability. A common procedure for comparing ante-mortem and post-mortem material is based on coding systems classifying frontal sinuses according to their morphological and metrical characteristics. However, the calculation of possible combinations is performed on the hypothesis that all the classified features are independent one from each other. This study aims at analysing the correlation among morphological and metrical characteristics of frontal sinuses. Two hundred CT scans of patients equally divided between males and females were segmented through the ITK-SNAP software. Number of accessory septations, scalloping and supra-orbital cells, side asymmetry and superiority, breadth, height, length and volume were extracted from the frontal sinuses of each subject. A possible relationship among morphological and metrical features was analysed through Pearson's correlation test, Mann-Whitney test or chi-square test according to the type of compared data (p < 0.05). In general, a positive correlation was found for all comparisons among metrical measurements (breadth, height, depth and volume) and number of septations, scalloping and supra-orbital cells (p < 0.05), but not between the number of scalloping and supra-orbital cells. In addition, side of asymmetry was positively related with side of superiority of the upper profile of frontal sinuses (p < 0.05). This study proved that morphological and metrical characteristics of frontal sinuses are strictly related one with each other: therefore, the coding systems based on these features should be applied with caution for personal identification, as the number of possible combinations is lower than reported by literature.

Three-Dimensional Assessment of Pharyngeal Volume on Computed Tomography Scans: Applications to Anesthesiology and Endoscopy.

Pharyngeal volume is important in anesthesiology for correctly assessing intubation procedures. However, most of studies are based on patients in upright position and do not assess possible relationships between pharyngeal volume and cranial size. This study aims at measuring pharyngeal volume in CT-scans and to assess possible statistically significant differences according to sex.Eighty healthy subjects (40 males and 40 females) aged between 21 and 86 years were retrospectively chosen from a hospital database of maxillofacial CT-scans; 3D segmentation was performed separately for naso-, oro- and laryngopharyngeal portion through ITK-SNAP software, and their volume was calculated. Three cranial measurements were obtained: distance between anterior and posterior nasal spine, upper facial height (nasion-prosthion) and biorbital breadth (ectoconchion-ectoconchion distance).The effect of sex on volume for each pharyngeal portion was assessed through one-way ANCOVA test using each of the 3 cranial measurements as covariate (P < 0.05).On average, the volume of nasopharynx, oropharynx and laryngopharynx was 7.2 ±â€Š2.7 cm, 7.5 ±â€Š4.2 cm, 3.5 ±â€Š2.2 cm respectively in males, and 6.4 ±â€Š2.9 cm, 5.2 ±â€Š2.1 cm, 3.0 ±â€Š1.8 cm in females. Statistically significant differences according to sex were found only for oropharyngeal volume, independently from cranial measurements (P < 0.05).This study provides data concerning volume of pharyngeal air space in supine subjects: these reference standards can be useful for anaesthesiologic procedures.

Relation between volume of sphenoid sinuses and protrusion of Vidian nerve: possible applications to Vidian neurectomy.

PURPOSE: Vidian neurectomy is a surgical procedure applied to different pathological conditions, including chronic rhinitis and sphenopalatine neuralgia. The choice of the correct surgical approach depends upon the possible protrusion of Vidian nerve into the sphenoid sinuses. The present study analyzes the possible relationship between protrusion of Vidian nerve and volume of sphenoid sinuses. METHODS: In total, 320 maxillofacial CT-scans were retrospectively assessed. Subjects equally divided among males and females (age range 18-94 years) were divided into three groups according to the profile of Vidian nerve protrusion: type 1: Vidian nerve inside the sphenoid corpus; type 2: partially protruding into the sphenoid sinus; and type 3: entirely protruding into the sphenoid sinus through a stalk. Volume of sphenoid sinuses was extracted through the ITK-SNAP-free software and automatically calculated. Possible statistically significant differences in prevalence of the three types between males and females were assessed through Chi-squared test (p < 0.05). Differences in volume of sphenoid sinuses in subjects included within the three types were assessed through one-way ANOVA test (p < 0.05), separately for males and females. RESULTS: Type 2 was the most prevalent (46.5%), followed by type 1 (38.8%) and type 3 (14.7%), without significant differences according to sex (p > 0.05). Volume significantly increased passing from type 1 to type 3 both in males (p < 0.01) and in females (p < 0.01). CONCLUSIONS: The results prove the existence of a strict relationship between sphenoid sinuses pneumatization and protrusion of the Vidian canal and give a contribution to the knowledge of this important anatomical variant in endoscopic surgery.

Relationship between sphenoid sinus volume and accessory septations: A 3D assessment of risky anatomical variants for endoscopic surgery.

Sphenoid sinus accessory septations involve serious complications during their removal for the injury of the internal carotid artery (ICA) and the optic nerve (ON). The relationships of this anatomical variant with sphenoid size still remain unclear. In the present study, 260 patients (equally divided among sexes, aged between 18 and 92 years) were retrospectively assessed. Number of accessory septations and their relationship with ICA and ON were recorded. The 3D model of sphenoid sinuses was extracted. Pearson's coefficient was calculated to assess correlations between the volume of sphenoid sinuses and the number of septations (P < 0.05). Sex-related differences in prevalence of septations inserted onto ICA or ON were assessed through chi-square test (P < 0.05). Differences in volume between patients with and without ICA or ON septal insertions were assessed through Mann-Whitney test (P < 0.05). In most of the cases, two septations were found (24.6%), whereas only 21.9% of patients did not show any septum. ICA and ON septal insertions were found in 20.8% and 7.7% of cases, respectively. Number of septations significantly increased with sinus volume, independently from sex (P < 0.001). Moreover, volume was significantly higher in patients with ICA septal insertion (P < 0.001), whereas no difference was found between subjects with and without ON septal insertion (P > 0.05). The present study first proved that septations and probability of ICA insertion are related with sphenoid volume. On the other side, ON insertion does not depend upon sphenoid sinuses size. Anat Rec, 303:1300-1304, 2020. © 2019 American Association for Anatomy.

Three-dimensional analysis of sphenoid sinus uniqueness for assessing personal identification: a novel method based on 3D-3D superimposition.

Sphenoid sinuses are considered the most variable structures of human body: therefore, they may be used for personal identification, through the application of 3D segmentation procedures. This study aims at proposing a new protocol for personal identification based on 3D-3D superimposition of sphenoid sinuses segmented from head CT scans. Adult subjects (equally divided among males and females) who underwent two head CT scans were extracted from a hospital database. Sphenoid sinuses were segmented through ITK-SNAP software and the corresponding 3D models were automatically superimposed to obtain 40 matches (when they belonged to the same person) and 260 mismatches (when they were extracted from different individuals). The RMS (root mean square) point-to-point distance was then calculated for all the superimpositions: differences according to sex and group (matches and mismatches) were assessed through the Mann-Whitney test (p < 0.05). On average, the RMS value was almost ten times smaller in matches (0.22 ± 0.11 mm) than in mismatches (2.16 ± 0.57 mm) with a statistically significant difference according to group (p < 0.05), but not to sex (p > 0.05). The study proposed a new method for assessing personal identification from segmented 3D models of sphenoid sinuses, useful in the forensic contexts where other methods might not be implementable or successful.

Relationship between sphenoid sinus volume and protrusion of internal carotid artery and optic nerve: a 3D segmentation study on maxillofacial CT-scans.

PURPOSE: Anatomy of sphenoid sinuses has acquired a growing importance with the diffusion of transsphenoidal surgical procedures. A common risk in these practices is the damage of internal carotid artery (ICA) and optic nerve (ON), which may protrude into the sphenoid air cavities. This study aims at analysing the relationships between sphenoid sinuses volume and protrusion of ICA and ON. METHODS: 260 head CT-scans were retrospectively analysed (equally divided among males and females, age range 20-92 years). Volume was segmented through ITK-SNAP software. In addition, the subjects were classified into four groups: no protrusion of any structure (group 1), protrusion of ICA (group 2), protrusion of ON (group 3), protrusion of both ICA and ON (group 4). Possible statistically significant differences in prevalence of the four groups according to gender were assessed through Chi-squared test (p < 0.05). Differences in volume between the four groups were assessed through one-way ANOVA test (p < 0.05), separately for males and females. RESULTS: Group 1 was the most frequent (40.0%), followed by group 4 (27.7%) and group 2 (18.5%), without any difference according to gender. For what concerns volume, cases of ICA and concomitant ICA + ON protrusion had significantly larger sinuses, whereas isolated ON protrusion did not modify sinus volume. CONCLUSIONS: Results show that protrusion of ICA is positively related with the volume of sphenoid sinuses, whereas the same relation was not verified for ON: surgeons should accurately consider possible ON protrusion in each case, as it may occur independently from sphenoid sinuses volume.

Anatomic Characteristics of Intrapetrous Carotid Artery: A 3-Dimensional Segmentation Study on Head Computed Tomography Scan.

BACKGROUND: The intrapetrous carotid artery (IPCA) is one of the most unexplored anatomic regions, and its 3-dimensional reconstruction in living subjects is still missing. This study aims to describe the IPCA on 3D models extracted from head computed tomography (CT) scans. METHODS: The intrapetrous carotid artery was manually segmented on head CT scans of 100 healthy patients free from vascular and neurologic pathologies (50 men and 50 women; age range, 18-91 years). Angles of the posterior and anterior genu, diameter and length of the horizontal portion, and volume of the entire canal were calculated through 3D analysis software. Statistically significant differences according to sex and side were assessed through 2-way analysis of variance (P < 0.05). Correlation of each measurement with age was calculated as well. RESULTS: On average, the angles of the posterior and anterior genu were 120.1° ± 10.4° and 118.0° ± 10.0° in men and 119.5° ± 9.2° and 117.6° ± 10.3° in women, respectively, without statistically significant differences according to sex or side (P > 0.05). The average length and diameter of the horizontal part were, respectively, 25.5 ± 2.9 and 5.8 ± 0.8 mm in men and 24.0 ± 2.3 and 5.3 ± 0.8 mm in women. The volume of the IPCA was 0.941 ± 0.215 cm3 in men and 0.752 ± 0.159 cm3 in women. The length and diameter of the horizontal portion and the volume of the IPCA showed statistically significant differences according to sex (P < 0.05). No correlation with age was found. CONCLUSIONS: This study provides data concerning not only linear and angular measurements, but also volumes of the IPCA, which are useful in planning surgical interventions of the cranial base.

An innovative 3D-3D superimposition for assessing anatomical uniqueness of frontal sinuses through segmentation on CT scans.

Anatomical uniqueness plays a significant role in the personal identification process of unknown deceased. Frontal sinuses have been widely used in the past decades for this purpose, mostly using 2D X-ray techniques. However, the modern 3D CT-based segmentation methods may help in developing novel and more reliable methods of identification. This study aims at assessing the anatomical uniqueness of frontal sinuses through the 3D model registration. Thirty subjects who underwent two maxillofacial CT scans (interval: 1 month to 5 years) were selected from a hospital database. Frontal sinuses were automatically segmented through ITK-SNAP open source software and the 3D models belonging to the same patient were automatically superimposed according to the least point-to-point difference between the two surfaces. Two hundred patients were randomly selected from the same database and undergo the same procedure to perform 200 superimpositions of frontal sinuses belonging to different individuals, equally divided between males and females (mismatches). Statistically significant differences of average root mean square (RMS) point-to-point distance between the group of matches and mismatches, as well as possible differences according to sex, were assessed through Mann-Whitney U test (p < 0.05). In the group of matches, RMS ranged between 0.07 and 0.96 mm (mean RMS 0.35 ± 0.23 mm), while in the group of mismatches, it ranged between 0.96 and 10.29 mm (mean RMS 2.59 ± 1.79 mm), with a statistically significant difference (p < 0.0001). Neither the matches nor the mismatches group showed statistically significant differences according to sex. This study proposes a novel 3D approach for the assessment of anatomical uniqueness of frontal sinuses, providing both morphological and quantitative analysis, and a new method of identification based on 3D assessment of frontal sinuses, applicable when ante-mortem CT scans are available.

Anatomy of the pterygopalatine fossa: an innovative metrical assessment based on 3D segmentation on head CT-scan.

PURPOSE: The pterygopalatine fossa is an important anatomical structure for several surgical and anaesthesiologic procedures; yet, very few data are available about its size. This study aims at providing a metrical assessment of pterygopalatine fossa through an innovative 3D segmentation procedure on head CT-scans. METHODS: CT-scans from 100 patients (50 males and 50 females) aged between 18 and 85 years were chosen for the study. Right and left pterygopalatine fossae were segmented through ITK-SNAP open source software. Height and volume were calculated on the acquired 3D models. In addition, anterior-posterior nasal spine distance, upper facial height (nasion-prosthion) and biorbital breadth (ectoconchion-ectoconchion) were measured as well. Statistically significant differences of height and volume according to sex and side were assessed through two-way ANOVA test: sexually dimorphic measurements were further assessed through one-way ANCOVA test using the three cranial measurements as covariates (p < 0.05). RESULTS: On average pterygopalatine fossa height was 24.1 ± 3.5 mm in males, and 22.8 ± 3.4 mm in females, whereas volume was 0.930 ± 0.181 cm3 in males and 0.817 ± 0.157 cm3 in females, with statistically significant differences according to sex (p < 0.05), but not to side (p > 0.05); interaction was negligible for both the measurements. ANCOVA test verified that sexual dimorphism of both measurements is independent from general cranial size (p < 0.05). CONCLUSIONS: The present study highlighted the sexual dimorphism of pterygopalatine fossa: results may improve the knowledge of this anatomical structure difficult to explore, but crucial in several fields of clinics and surgery.

Can Volumetric and Morphological Variants of Sphenoid Sinuses Influence Sinuses Opacification?

Improvements in computed tomography and in functional endoscopic sinus surgery have recently increased interest toward paranasal sinus anatomy and anatomic variations that can be observed in patients affected by sinusitis. Isolated sphenoid sinusitis is a relatively rare pathology, often related to nonspecific symptoms, therefore making diagnosis difficult. The correlation between this type of sinusitis and anatomical variants remains unclear.The authors' aim was to retrospectively revise paranasal sinuses computed tomography scans of patients affected by sphenoid sinusitis, compared with a control group, analyzing the types of sphenoid sinus and the presence of aberrant pneumatization, and performing a segmentation of the sphenoid sinuses to calculate the volumes.Sphenoid sinuses of 60 patients affected by sinus opacification, compared with a control group, were segmented. Type of sinus (sellar, presellar, postsellar) and presence of aberrant pneumatization were assessed as well. Possible statistically significant differences in volumes according to sex and group were assessed through 2-way ANOVA test (P < 0.05). Post-hoc test was assessed through Student t test. χ test was applied in order to verify the statistically significance of differences in frequency of different types of sinus pneumatization variants (P < 0.05).Average volume of sphenoid sinuses in males was of 7.672 cm and of 7.751 cm in females within the group of patients; statistically significant differences in volume were found according to sex (P: 0.342), but not between the patients and control group (P: 0.0929). Post-hoc test verified that males affected by sinus opacification showed smaller volumes in comparison with the control males (P < 0.05). In addition, patients by affected sinus opacification showed more frequently the postsellar type and were less affected by pneumatization variants of the sphenoid bone than the control group (P < 0.05).This study first suggests the possible protective role of variants of pneumatization in the development of sphenoid sinus opacification.

Anatomical variants of ethmoid bone on multidetector CT.

Anatomical variants of the ethmoid bone have a special importance in several fields, especially in otolaryngology; a precise understanding of the complex anatomy and anatomic variations of the ethmoid bone is crucial for radiological diagnosis of paranasal pathology and for surgical work-up in order to avoid potential complications. The present study aims at helping general radiologists to become familiar with the most common forms of ethmoid anatomical variants and their clinical relevance.

Assessing symmetry of zygomatic bone through three-dimensional segmentation on computed tomography scan and "mirroring" procedure: A contribution for reconstructive maxillofacial surgery.

PURPOSE: Surgical reconstruction of zygomatic bones in cases of traumatic injuries is a frequent event: assessment of symmetry is mandatory for a correct restoration of zygomatic shape, but the literature is discordant about its quantification. The purpose of this study is to show a novel method for assessing symmetry of zygomatic bone through mirroring of 3D models segmented on CT-scan. MATERIALS AND METHODS: A total of 100 patients (50 male and 50 female), divided into two age groups (18-49 years and 50-92 years) were selected from the computed tomography (CT) scan database of a hospital in northern Italy. Zygomatic bones from each patient were segmented, and the left bone was automatically mirrored and registered on the right one according to the least point-to-point distance between the two surfaces. The mean and root mean square (RMS) distance between the two models was then calculated. Statistically significant differences according to sex and age groups were assessed through two-way analysis of variance (p < 0.05). In addition, the effect size of differences was calculated. RESULTS: The method proved to be repeatable, with inter- and intraoperator errors lower than 5%. Overall, mean and RMS point-to-point distances were respectively 0.01 mm and 0.84 mm, without statistically significant differences according to sex or age (p > 0.05), and with negligible effect size. CONCLUSION: This study provides an innovative method for assessing the symmetry of the zygomatic bone based on surface analysis. Results may provide useful indications for the reconstruction of zygomatic bones in maxillofacial surgery.

Sella turcica bridging and ossified carotico-clinoid ligament: Correlation with sex and age.

Aim Sella turcica bridging and ossified carotico-clinoid ligament are two variants of the sella turcica, the origin of which is partially unknown. These variations should be properly recognised, as they may hamper the removal of the anterior clinoid process in surgical procedures. Therefore, our aim was to determine the prevalence of these two anatomical variants and to investigate their prevalence according to patient sex and age in a series of maxilla computed tomography scans. Materials and methods We revised 300 computed tomography scans of the head from northern Italian patients, stratified into three age groups (18-40 years, 41-60 years, >60 years): a logistic regression analysis was used to explore an association of sella turcica bridging with age and sex through Matlab software, also including a test for the extracted model ( P < 0.05). Results The mean prevalence of sella turcica bridging and ossified carotico-clinoid ligament were 0.16 ± 0.06 (48/300, 16.0%) and 0.09 ± 0.03 (26/300, 8.7%), respectively. Statistically significant differences according to sex were found neither for sella turcica bridging ( P = 0.345) nor for ossified carotico-clinoid ligament ( P = 0.412). Only sella turcica bridging showed a correlation with age ( P = 0.007). In addition, the two variants were often associated, as patients without sella turcica bridging usually did not show ossified carotico-clinoid ligament ( P < 0.001). Discussion Our results suggest an association between the two variants, and provide a novel contribution to the debate around their origin.

Volumetric assessment of sphenoid sinuses through segmentation on CT scan.

PURPOSE: Computed tomography represents the gold standard for the assessment of morphological characteristics of sphenoid sinuses, whose anatomy has acquired a novel interest because of the recent introduction of transsphenoidal surgery and robot-assisted procedures. One of the most relevant parameters for planning surgical intervention is the volume of sphenoid sinuses, and with time few population studies have been published. However, at present, no data are available concerning the relation between volume and anatomical variants of sphenoid sinuses. METHODS: We retrospectively evaluated head CT-scans of 100 patients (age range 25-99 years; mean age males 45.0; mean age females 50.5 years) to calculate the volume of sphenoid sinuses through automatic segmentation. Possible statistically significant differences according to sex and variants of pneumatization, and type of sinus were assessed, respectively, through Student's t test and one-way ANOVA test (p < 0.05). RESULTS: Average volume of sphenoid sinuses in males was 10.005 ± 5.101 cm3, in females 7.920 ± 3.176 cm3. Differences according to sex were statistically significant (p < 0.05). Patients with pneumatization of pterygoid processes, dorsum sellae and anterior clinoid processes had a significantly higher volume than unaffected subjects. Moreover, differences of volume according to the type of sphenoid sinus were statistically significant (p < 0.05). CONCLUSIONS: Results show that volume of sphenoid sinuses strongly depend upon the type of sinus and possible pneumatization variants. Moreover, the important of ethnic variability is confirmed.

Anatomical variants of sphenoid sinuses pneumatisation: a CT scan study on a Northern Italian population.

Sphenoid bone may be affected by different variants of pneumatisation, which have a relevant importance from a clinical and surgical point of view. The description of such variants in different populations may give useful information. However, few articles describe the variability of sphenoid pneumatised structures and none of them focuses on Northern Italian population. Variants of pneumatisation of sphenoid bone were described in a sample of 300 Northern Italian patients who underwent a CT scan. More than fifty-seven percent of patients showed a form of anatomical variant: the most common form was the pneumatised pterygoid processes (39.6%), followed by dorsum sellae (32.9%) and clinoid processes (20.3%), without statistically significant differences between males and females (p > 0.01). In 26.3% of patients, a combined pneumatisation of these three structures was observed, being the combination pterygoid processes-dorsum sellae the most frequent (11.3%). In 9.3%, all the three sphenoid structures were affected. This article is the first description of the prevalence of different variants of pneumatisation in a Northern Italian population: the occurrence of such forms has to be acknowledged for their possible clinical and surgical consequences.