Anatomical variants of ethmoid bone on multidetector CT

The relationship between structures affecting maxillary sinus ventilation and maxillary sinus volume: a CT study

PURPOSE

This study aims to identify anatomical variations inside and outside the maxillary sinus (MS), determine their prevalence and coexistence, and investigate their relationship with MS volume in individuals without MS pathology, using ImFusion Suite software.

METHODS

Analysis of 330 paranasal CT scans obtained from the radiology archive (2018-2021) was performed using the ImFusion Suite program. Anatomical variations, including accessory ostium, Haller cells, ethmomaxillary sinus, concha anomalies, septa, and impacted teeth, were identified and their frequency of coexistence was determined. MS volume and nasal septum deviation (NSD) angle were measured. The relationship between MS volume and gender, as well as the impact of anatomical variations on MS volume, was analyzed. Statistical analyses were conducted using SPSS software.

RESULTS

The most common anatomical variation was NSD (98%), while the least common was ethmomaxillary sinus (9.4%). Middle and inferior concha hypertrophy were more frequent in males, whereas concha bullosa and impacted teeth were more prevalent in females (p < 0.05). A normal anatomical appearance on CT scans was observed in only 2.1% of cases (3.5% in males; 1.1% in females), with a notable coexistence of multiple variations. MS volume was significantly higher in males (right: 16.79 ± 5.23 cm3; left: 16.39 ± 5.61 cm3) than in females (right: 14.44 ± 4.54 cm3; left: 14.59 ± 4.62 cm3) (p < 0.05). MS volume was significantly smaller when the NSD angle was ≥9° and larger in the presence of septa.

CONCLUSION

This study provides a comprehensive analysis of anatomical variations in the MS and their relationship with MS volume. The findings indicate that septa increase MS volume, while a higher NSD angle (≥9°) is associated with reduced MS volume. Other variations, including accessory ostium, Haller cells, and concha anomalies, showed no significant impact on MS volume. These results highlight the importance of detailed radiological evaluation in clinical and surgical planning.

Is There Any Racial Difference in Term of Anatomical Variations of Nasal and Paranasal Sinus Structures

The aim of our study was to determine the anatomical variations detected on computed tomography radiological imaging of the paranasal sinus between citizens and refugees patient groups and to reveal the differences between the two patient groups. In this study, the data from the files of 38 Turkish Citizens (Group 1), 41 Syrian Refugees (Group 2), a total of 79 patients who were admitted to the ENT Clinic of Adana City Training and Research Hospital due to rhinological complaints between 01.01.2019 and 01.01.2020 and had paranasal sinus tomography, were analyzed retrospectively. Due to the Syrian Civil War that started in 2011, more than 10 million Syrian have left their countries and immigrated to neighboring countries as refugees. The paranasal sinus area has a wide variety of variations. Congenital anomalies and normal anatomical variations in this area are important, although rarely, as they may have pathological consequences or may be a source of difficulty during surgery. In the study, 38 of 79 patients were in Group 1 (48.1%) and 41 were in Group 2 (51.9%). Of the patients, 30 were female (38%) and 49 were male (62%). The ages of the patients ranged from 9 to 78 years, with a mean age of 32.52 years. In our study, we could not find a statistically significant difference between Turkish Citizens and Syrian refugees in terms of anatomical variations detected on paranasal radiological imaging. We consider the number of patients in our study as a limitation of our study and we think that it is important to conduct studies with larger populations.

Anatomical variations of the ethmoid sinuses and their association with health or pathology of the ethmoid and maxillary sinuses in a Southern Chinese population: An analysis using cone-beam computed tomography

Purpose

The aim of this study was to evaluate the prevalence of clinically relevant anatomical variations of the ethmoid sinuses and their potential association with ethmoid and maxillary sinus pathologies on cone-beam computed tomography (CBCT) scans. Additionally, potential associations with different sides and demographic factors, including age and sex, were evaluated.

Materials and Methods

In total, 273 CBCT scans with complete ethmoid and maxillary sinuses were analyzed to determine the prevalence of Agger nasi cell, supraorbital ethmoid cell, Haller cell, Onodi cell, and ethmomaxillary sinus. In addition, the health or pathology of the ethmoid and maxillary sinuses was also recorded to assess correlations with the aforementioned variations.

Results

The prevalence of Agger nasi cell was found to be the highest (95.6%) in this study, followed by Onodi cell (60.4%), Haller cell (29.3%), and supraorbital ethmoid cell (19.4%). Ethmomaxillary sinus was the least common finding (16.5%). Males and persons above 61 years of age had a significantly higher frequency of supraorbital ethmoid cell and Onodi cell, respectively. However, no significant relationships were noted between anatomical variations of the ethmoid sinus and pathologies of the ethmoid or maxillary sinus.

Conclusion

There was a high prevalence of ethmoid sinus variations in this Southern Chinese population. The prevalence of Agger nasi cell and Onodi cell was higher than that of other anatomical variations of the ethmoid sinuses. Anatomical variations of the ethmoid sinuses were not associated with ethmoid or maxillary sinus pathologies in this patient cohort.

Ambiguous "olfactory" terms for anatomic spaces adjacent to the cribriform plate: A publication database analysis and quest for uniformity

A precise nomenclature and terminology is the foundation of communication in Anatomy and related biomedical sciences. The olfactory bulbs and nerves lie above and below the cribriform plate (CP), respectively. Hence, many anatomical landmarks in this region have names adopting the term "olfactory" as qualifiers. Ambiguous use of these "olfactory" terms exists, with some potential repercussions on patient treatments. We performed a publication database analysis to determine the frequency of misuse of names for seven anatomical "olfactory" spaces close to the CP and nasal cavity. We searched PubMed® publications having the keyword "olfactory" in their title or abstract, plus one of seven other keywords: "groove", "fossa", "recess", "cleft", "vestibule", "sulcus", and "cistern". We reviewed all abstracts for accuracy of these terms relative to accepted norms or customary definitions. By February 2020, we found all these keywords in 1255 articles. For the terms olfactory "groove" and "fossa", the number of relevant articles (and percentage of those inaccurately using these terms) were 374 (1.1%), and 49 (8.2%), respectively. All 52 abstracts containing "olfactory" and "vestibule" were irrelevant, relating to the "nasal vestibule" and olfactory function, instead of "olfactory vestibule". Overall, terms used to describe "olfactory" spaces near the CP are seldom ambiguous or inaccurate, but the terms olfactory "groove" and "fossa" are occasionally misused, We propose several new "olfactory" terms for inclusion in the Terminologia Anatomica, and stress the need for uniform nomenclature leading to greater consistency and accuracy in clinical use of anatomical terms containing the word "olfactory" as a descriptor.

Morphometric characteristics of the sphenoid sinus and potential influencing factors: a retrospective assessment using cone beam computed tomography (CBCT)

The present study aimed to evaluate the morphological characteristics of the sphenoid sinus (SS), and the impact of potential influencing factors on the morphometric features using CBCT imaging. CBCT scans of 148 patients, aged between 15 and 85 (32.88 ± 15.33) years were retrospectively evaluated. DICOM files from the CBCT scans were imported into semi-automatic software and the SS of each patient was assessed for the morphological characteristics including configuration, symmetry, extension, shape, septation, volume, and maximum diameter. Furthermore, potential influencing factors such as age, gender, side, and sinus condition were analysed. A significant association was observed between sinus extension and age. Septation was also found to be significantly associated with age, gender and sinus condition. Besides, sinus volume was significantly associated with gender and sinus condition. No significant influence of shape and side on the morphometric features was noticed. The average volume and diameter of the SS were 6576.92 ± 3748.12 mm³ and 30.48 ± 9.28 mm, respectively. In conclusion, the present findings indicate that age, gender and sinus condition have a significant impact on the morphometric characteristics of the SS. Mature sinuses exhibit a post-sellar extension pattern until middle age. In addition, males, and sinuses with healthy sinus condition have larger volumes compared to females and pathological sinuses.

Segmentation procedures for the assessment of paranasal sinuses volumes

BACKGROUND

The paranasal sinuses are complex anatomical structures, characterised by highly variable shape, morphology and size. With the introduction of multidetector scanners and the development of many post-processing possibilities, computed tomography became the gold standard technique to image the paranasal sinuses. Segmentation allows the extraction of metrical and shape data of these anatomical components that can be applied for diagnostic, education, surgical planning and simulation, and to plan minimally invasive interventions in otorhinolaryngology and neurosurgery.

DISCUSSION

Our aim was to provide a review of the existing literature on segmentation, its types and application, and the data obtained from this procedure. The literature search was conducted on PubMed (including Medline), ScienceDirect and Google Scholar databases, using the keywords as follows: 'paranasal sinuses', 'frontal sinus', 'maxillary sinus', 'sphenoid sinus', 'ethmoid sinus', in all possible combinations with the keywords 'segmentation' and 'volumetric analysis'. Inclusion criteria were: articles written in English, on living human subjects, on the adult population and focused on paranasal sinuses analysis.

CONCLUSION

This article provides an overview of the types and main application of segmentation procedures on paranasal sinuses, and the results provided by the studies on this topic.

Nasal cavities and the nasal septum: Anatomical variants and assessment of features with computed tomography

The nasal cavities are complex anatomical structures with high inter-individual variability that relates to different functions. Different anatomic variants may manifest at this site, mainly belonging to the nasal septum and turbinates. Precise knowledge of the anatomy and variants is fundamental for both radiologists and ENT surgeons. This article provides an overview of the main anatomic variants and their frequency, according to the existing literature, as well as ongoing research on nasal cavity segmentation in order to obtain personal 3D models and to predict post-surgical results.

Posterior ethmoid cell expansion towards the inferolateral region of the sphenoid sinus: a computed tomography study

OBJECTIVE

The aim of this study was to investigate the anatomical imaging characteristics of posterior ethmoid cells (PEs) expanding towards the inferolateral region of the sphenoid sinus (SS).

METHODS

This study included a total of 278 inpatients (556 sides) whose paranasal sinus computed tomography (CT) scans were reviewed and collected from May 2018 to February 2019. The anatomical imaging characteristics of PEs expanding towards the inferolateral region of the SS were observed.

RESULTS

PEs expanding towards the inferolateral region of the SS formed an inferolateral spheno-ethmoid cell (ISEC). ISECs were observed on three sides (0.54%; 3/556) in three cases (1.08%; 3/278). All of the ISECs were present unilaterally on the right side of the SS. The ISECs originated from the most posterior ethmoid cell; they were first located at the medial aspect of the orbital apex, pneumatized continually backward to the inferomedial wall of the orbital apex, and then extended into the lateral region of the SS. The ISECs further extended laterally, inferiorly and posteriorly beyond the sphenoid body into the greater wing and/or pterygoid process.

CONCLUSION

An ISEC is a rare variation of ethmoid air cells. Preoperative recognition of ISECs is essential to achieve safe and effective endoscopic sinus surgery because of the important anatomical location.

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.