CT-based manual segmentation and evaluation of paranasal sinuses

Analysis of sphenoid sinus and ethmoid sinus volume and asymmetry by sex: A 3D-CT study

PURPOSE

To measure the volume of the sphenoid and ethmoid sinuses and to analyse the asymmetry index values by age/gender.

METHODS

Three-dimensional (3D) Computed Tomography (CT) images of 150 individuals (75 females, 75 males) of both sexes between the ages of 18-75 were included in our study. Sphenoid and ethmoid sinus volumes were measured using the 3D Slicer software package on these images, and the asymmetry index was calculated.

RESULTS

In our study, mean sphenoid sinus volume (female right: 4264.4 mm3, left: 3787.1 mm3; male right: 5201.1 mm3, left: 4818.2 mm3) and ethmoid sinus volume (female right: 3365.1 mm3, left: 3321.2 mm3; male right: 3440.9 mm3, left: 3459.5 mm3) were measured in males and females. Left sphenoid sinus values of males were statistically higher than females (p = 0.036). No statistically significant relationship existed between age, sinus volumes, and asymmetry index (p > 0.05). A statistically weak positive correlation existed between males' left sphenoid and ethmoid sinus volume (rho = 0.288; p = 0.012). There was no statistical relationship between asymmetry index in the whole group (p > 0.05). A statistically weak negative correlation was found between sphenoid and ethmoid sinus asymmetry index in males (rho=-0.352; p = 0.002). There was no statistical relationship between asymmetry index in females (p > 0.05).

CONCLUSION

Knowing paranasal sinus morphology, morphometry, and asymmetry index value will be significant for preoperative and postoperative periods.

Evaluation of the relationship between sphenoid sinus morphology and area and volume by computed tomography

OBJECTIVES

The aim of this study is to investigate the effect of sphenoid sinus pneumatization types, Onodi cell (OC), internal carotid artery (ICA), optic nerve (ON) on sinus volume and area on computed tomography (CT) images.

METHODS

The CT images of 150 patients were evaluated. Sphenoid sinus pneumatization types, OC prevalence, protrusion and dehiscence of ICA and ON, the volume and area were evaluated.

RESULTS

The sinus volume and area were statistically higher in patients with bilateral protrusion of ICA and ON then patients without protrusion of ICA and ON. The mean volume and area of sinus were 9949.4 ± 351.0 mm3 and 4570.9 ± 1604.9 mm2, respectively. The volume and area of sphenoid sinus did not differ significantly between groups with and without OC. The postsellar b type sphenoid sinus had the highest volume, while conchal type has the least volume.

CONCLUSIONS

Bilateral protrusion and dehiscence of ICA and bilateral protrusion of ON caused a significant increase in the sphenoid sinus volume and area. The presence of ICA and ON, the pneumatization of the sinus is an anatomical structure that can affect the sinus volume and area. Before the operation, three-dimensional evaluation should be performed to determine whether these structures are bilateral/unilateral and it should be remembered that the sinus volume and area can change.

Sex Estimation From the Paranasal Sinus Volumes Using Semiautomatic Segmentation, Discriminant Analyses, and Machine Learning Algorithms

ABSTRACT

The aims of this study were to determine whether paranasal sinus volumetric measurements differ according to sex, age group, and right-left side and to determine the rate of sexual dimorphism using discriminant function analysis and machine learning algorithms. The study included paranasal computed tomography images of 100 live individuals of known sex and age. The paranasal sinuses were marked using semiautomatic segmentation and their volumes and densities were measured. Sex determination using discriminant analyses and machine learning algorithms was performed. Males had higher mean volumes of all paranasal sinuses than females ( P < 0.05); however, there were no statistically significant differences between age groups or sides ( P > 0.05). The paranasal sinus volumes of females were more dysmorphic during sex determination. The frontal sinus volume had the highest accuracy, whereas the sphenoid sinus volume was the least dysmorphic. In this study, although there was moderate sexual dimorphism in paranasal sinus volumes, the use of machine learning methods increased the accuracy of sex estimation. We believe that sex estimation rates will be significantly higher in future studies that combine linear measurements, volumetric measurements, and machine-learning algorithms.

Contribution of Morphology of Frontal Sinuses (Linear and Volumetric Measurements) to Gender Identification Based on Cone Beam Computed Tomography Images (CBCT): A Systematic Review

Human identification is considered as an important step in the reconstruction of biological profiles, especially of unknown individuals. Frontal sinuses (FS) have been regarded as an ideal anatomical structure for individualisation because few pathological conditions can potentially alter their shape.

AIM

The aim of this review was to evaluate scientific evidence published since January 2010 and determine whether the dimensions and volume of FS might be useful parameters for gender determination and human identification, based only on cone beam computed tomography images (CBCT).

METHODS

This review was performed in accordance with the PRISMA statement. Four databases were searched for articles published between January 2010 and June 2022.

RESULTS

A total of 195 records were initially identified, and 90 remained after a manual duplicate check. Eight articles were selected for a full review according to the inclusion and exclusion criteria after title and abstract screening. A total of 718 participants (359 males and 359 females) were identified from the included studies. Frontal sinus volume (FSV) was significantly higher in male individuals. Frontal sinus height (FSH) and volume were the superior discriminating parameters for forensic identification.

CONCLUSIONS

This review demonstrates that assessment of FS based on CBCT images could be beneficial for gender identification in forensic science. According to the obtained studies, frontal sinus volume (FSV) and frontal sinus height (FSH) are significant greater in males than in females, providing an additional complementary method. Larger sample size and common measurement protocols are needed to verify their usefulness.

Deep learning-based fully automatic segmentation of the maxillary sinus on cone-beam computed tomographic images

The detection of maxillary sinus wall is important in dental fields such as implant surgery, tooth extraction, and odontogenic disease diagnosis. The accurate segmentation of the maxillary sinus is required as a cornerstone for diagnosis and treatment planning. This study proposes a deep learning-based method for fully automatic segmentation of the maxillary sinus, including clear or hazy states, on cone-beam computed tomographic (CBCT) images. A model for segmentation of the maxillary sinuses was developed using U-Net, a convolutional neural network, and a total of 19,350 CBCT images were used from 90 maxillary sinuses (34 clear sinuses, 56 hazy sinuses). Post-processing to eliminate prediction errors of the U-Net segmentation results increased the accuracy. The average prediction results of U-Net were a dice similarity coefficient (DSC) of 0.9090 ± 0.1921 and a Hausdorff distance (HD) of 2.7013 ± 4.6154. After post-processing, the average results improved to a DSC of 0.9099 ± 0.1914 and an HD of 2.1470 ± 2.2790. The proposed deep learning model with post-processing showed good performance for clear and hazy maxillary sinus segmentation. This model has the potential to help dental clinicians with maxillary sinus segmentation, yielding equivalent accuracy in a variety of cases.

Three-Dimensional Evaluation of the Frontal Sinus in Koreans

(1) Background: Among the four paranasal sinuses, the frontal sinus is in the frontal bone. Recent research trends have been focusing on identifying sex based on the frontal sinus. Thus, this study aimed to provide reference data for the frontal sinus in Korean adults by comparing their sizes using a 3D program. Moreover, this study examined the correlation between the size of the frontal sinus and the length of cranial bone. (2) Methods: Cone-beam computed tomography (CBCT) data were obtained from 60 (male 30, female 30) patients in their 20 s who visited the Department of Dankook University Hospital (DKUDH IRB 2020-01-007). The provided patient CBCT data were utilized to reconstruct the patients’ frontal sinuses and cranial bones in 3D using the Mimics (version 22.0, Materialise, Leuven, Belgium) 3D program. All measurements were analyzed using SPSS (ver. 23.0, IBM Corporation, Armonk, NY, USA). (3) Results: By comparing the frontal sinus size of Korean adults according to sex using a 3D program, this study revealed that males had larger frontal sinuses than females. (4) Conclusions: The findings of this study could help in preventing complications that occur in various clinical treatments and analyzing the growth of the frontal sinus in the future.

CAFS: An Attention-Based Co-Segmentation Semi-Supervised Method for Nasopharyngeal Carcinoma Segmentation

Accurate segmentation of nasopharyngeal carcinoma is essential to its treatment effect. However, there are several challenges in existing deep learning-based segmentation methods. First, the acquisition of labeled data are challenging. Second, the nasopharyngeal carcinoma is similar to the surrounding tissues. Third, the shape of nasopharyngeal carcinoma is complex. These challenges make the segmentation of nasopharyngeal carcinoma difficult. This paper proposes a novel semi-supervised method named CAFS for automatic segmentation of nasopharyngeal carcinoma. CAFS addresses the above challenges through three mechanisms: the teacher-student cooperative segmentation mechanism, the attention mechanism, and the feedback mechanism. CAFS can use only a small amount of labeled nasopharyngeal carcinoma data to segment the cancer region accurately. The average DSC value of CAFS is 0.8723 on the nasopharyngeal carcinoma segmentation task. Moreover, CAFS has outperformed the state-of-the-art nasopharyngeal carcinoma segmentation methods in the comparison experiment. Among the compared state-of-the-art methods, CAFS achieved the highest values of DSC, Jaccard, and precision. In particular, the DSC value of CAFS is 7.42% higher than the highest DSC value in the state-of-the-art methods.

Maxillary Sinusitis of Odontogenic Origin: Prevalence among 3D Imaging—A Retrospective Study

The aim of this study was to investigate the prevalence of maxillary sinus mucosal thickening and compare it to the presence of odontogenic pathology of adjacent teeth. Three hundred and twenty-one full maxilla cone-beam computed tomography scans were examined. The parameters investigated included signs of maxillary sinus mucosal thickening and the diagnosis and proximity of the adjacent teeth. Statistical analysis was conducted using IBM SPSS version-16.0 (SPSS Inc., Chicago, IL, USA). Out of the 2001 teeth examined, 888 (44.4%) were associated with mucosal thickening with a significant difference between the different tooth types (p = 0.04). Mucosal thickening in a maxillary sinus was more likely if the neighboring teeth had apical disease. Interruption of the maxillary sinus floor was noticed more in specific teeth, particularly the first and second molars (p < 0.001). Sinusitis of odontogenic origin can be more prevalent than clinicians expect. The treatment of odontogenic sinusitis should be straightforward, whereby the diseased tooth is root treated or extracted. The sinusitis will then resolve if there are no other etiological factors.

Semi-Supervised Deep Learning Semantic Segmentation for 3D Volumetric Computed Tomographic Scoring of Chronic Rhinosinusitis: Clinical Correlations and Comparison with Lund-Mackay Scoring

Background: The traditional Lund-Mackay score (TLMs) is unable to subgrade the volume of inflammatory disease. We aimed to propose an effective modification and calculated the volume-based modified LM score (VMLMs), which should correlate more strongly with clinical symptoms than the TLMs. Methods: Semi-supervised learning with pseudo-labels used for self-training was adopted to train our convolutional neural networks, with the algorithm including a combination of MobileNet, SENet, and ResNet. A total of 175 CT sets, with 50 participants that would undergo sinus surgery, were recruited. The Sinonasal Outcomes Test-22 (SNOT-22) was used to assess disease-specific symptoms before and after surgery. A 3D-projected view was created and VMLMs were calculated for further comparison. Results: Our methods showed a significant improvement both in sinus classification and segmentation as compared to state-of-the-art networks, with an average Dice coefficient of 91.57%, an MioU of 89.43%, and a pixel accuracy of 99.75%. The sinus volume exhibited sex dimorphism. There was a significant positive correlation between volume and height, but a trend toward a negative correlation between maxillary sinus and age. Subjects who underwent surgery had significantly greater TLMs (14.9 vs. 7.38) and VMLMs (11.65 vs. 4.34) than those who did not. ROC-AUC analyses showed that the VMLMs had excellent discrimination at classifying a high probability of postoperative improvement with SNOT-22 reduction. Conclusions: Our method is suitable for obtaining detailed information, excellent sinus boundary prediction, and differentiating the target from its surrounding structure. These findings demonstrate the promise of CT-based volumetric analysis of sinus mucosal inflammation.

Research Active Posterior Rhinomanometry Tomography Method for Nasal Breathing Determining Violations

This study analyzes the existing methods for studying nasal breathing. The aspects of verifying the results of rhinomanometric diagnostics according to the data of spiral computed tomography are considered, and the methodological features of dynamic posterior active rhinomanometry and the main indicators of respiration are also analyzed. The possibilities of testing respiratory olfactory disorders are considered, the analysis of errors in rhinomanometric measurements is carried out. In the conclusions, practical recommendations are given that have been developed for the design and operation of tools for functional diagnostics of nasal breathing disorders. It is advisable, according to the data of dynamic rhinomanometry, to assess the functioning of the nasal valve by the shape of the air flow rate signals during forced breathing and the structures of the soft palate by the residual nasopharyngeal pressure drop. It is imperative to take into account not only the maximum coefficient of aerodynamic nose drag, but also the values of the pressure drop and air flow rate in the area of transition to the turbulent quadratic flow regime. From the point of view of the physiology of the nasal response, it is necessary to look at the dynamic change to the current mode, given the hour of the forced response, so that it will ensure the maximum possible acidity in the legend. When planning functional rhinosurgical operations, it is necessary to apply the calculation method using computed tomography, which makes it possible to predict the functional result of surgery.

Adaptive Localizing Region-Based Level Set for Segmentation of Maxillary Sinus Based on Convolutional Neural Networks

In this paper, we propose a novel method, an adaptive localizing region-based level set using convolutional neural network, for improving performance of maxillary sinus segmentation. The healthy sinus without lesion inside is easy for conventional algorithms. However, in practice, most of the cases are filled with lesions of great heterogeneity which lead to lower accuracy. Therefore, we provide a strategy to avoid active contour from being trapped into a nontarget area. First, features of lesion and maxillary sinus are studied using a convolutional neural network (CNN) with two convolutional and three fully connected layers in architecture. In addition, outputs of CNN are devised to evaluate possibilities of zero level set location close to lesion or not. Finally, the method estimates stable points on the contour by an interactive process. If it locates in the lesion, the point needs to be paid a certain speed compensation based on the value of possibility via CNN, assisting itself to escape from the local minima. If not, the point preserves current status till convergence. Capabilities of our method have been demonstrated on a dataset of 200 CT images with possible lesions. To illustrate the strength of our method, we evaluated it against state-of-the-art methods, FLS and CRF-FCN. For all cases, our method, as assessed by Dice similarity coefficients, performed significantly better compared with currently available methods and obtained a significant Dice improvement, 0.25 than FLS and 0.12 than CRF-FCN, respectively, on an average.

[Automated system of the determination of maxillary sinus morphometric parameters]

THE AIM OF THE STUDY

Was to compare manual, semi-automatic and automatic methods for determining the maxillary sinus volume using cone beam computed tomography (CBCT).

MATERIAL AND METHODS

CBCT images from 48 patients (96 maxillary sinuses) with no history of sinus and alveolar bone surgery, who were presented to Minsk medical centers, were used in this study. Neural network training was performed on CBCT scans of 42 patients (84 maxillary sinuses).The height, depth and width of the sinus were measured manually on CBCT scans of 6 patients (12 maxillary sinuses). Maxillary sinus volume (V) was calculated by the formula: V=height´depth´1/3 width. Semi-automatic segmentation was carried out by an expert radiologist. The convolutional neural network technology was applied for maxillary sinus automatic segmentation.

RESULTS

The largest values were revealed by using the automatic method for sinus volume measurement. These values were within the 95% confidence interval (±4.29 cm³) of the average sinus volume obtained from semi-automatic method.

CONCLUSION

The data obtained using the convolutional neural network technique (artificial intelligence) has a high correlation with the results of sinus morphometric analysis acquired through manual and semi-automatic methods. Automatic maxillary sinus segmentation technique does not require special user knowledge. This method is reproducible and it is implemented in a short time interval.

Volumetric Investigation of Sphenoid Sinus in an Elderly Population

The aims of this study were to determine the sphenoid sinus volume in an Austrian population, evaluate the relationship between volume and different types of pneumatization and investigate possible age-related sphenoid sinus volume degeneration in the elderly. A total of 50 human cadaver including 25 male and 25 female samples (=100 sphenoid sinuses, age range 65-100, mean age 84.52 ± 9.50) were selected to obtain volume and anatomical variants of pneumatization by using sphenoid sinus casts, made of quadrofunctional hydrophilic addition reaction silicone. The mean sphenoid sinus volume was 4.79 ± 2.39 cm. Males showed statistically significant larger sinus volumes than females (P = 0.048). The volume differed statistically significant for the different types of pneumatization (P < 0.001). The combined type of sphenoid sinus pneumatization presented the largest volume with 7.20 cm, followed by lateral, clival, sphenoid body, presellar, and conchal sinus type with 5.72, 5.63, 4.25, 2.08, and 0.5 cm, respectively. No significant correlation between age and sphenoid sinus volume was found (P = 0.707). This study highlights the close relationship between volume and morphology of sphenoid sinus and confirms ethnic variability. Moreover, our data shows no age-related volume degeneration.

A retrospective and tridimensional study of the maxillary sinus in patients with cleft lip and palate

INTRODUCTION

Structural or anatomic differences may arise during the development of the maxillary sinus and the process of fusion of the palate in the presence of cleft lip and palate. The present study aimed to compare the maxillary sinus volume of patients with unilateral cleft lip and palate and a control group (noncleft patients).

METHODS

In this retrospective case-control study, 160 cone-beam computed tomography images of 80 unilateral cleft lip and palate patients (41 males and 39 females; mean age, 12.7 ± 6.03 years) and 80 control patients (43 males and 37 females; mean age, 13.1 ± 6.27 years) were evaluated through the ITK-SNAP software (Cognitica, Philadelphia, Pa) to access the maxillary sinus volume. Analysis of covariance and regression analysis were used to assess the differences between the groups while considering the relationship between maxillary sinus volume, age, and sex.

RESULTS

No statistically significant differences were found in the maxillary sinus volume analyzing a unilateral cleft lip and palate and a control group (P = 0.677). Considering the cleft group, there is a tendency for the maxillary sinus volume of the cleft side to be smaller than its contralateral (P < 0.001). Statistically significant differences were found in the maxillary sinus volume, regarding the age and sex of cleft and noncleft patients (P < 0.001 for age; P = 0.001 for sex).

CONCLUSIONS

According to these results, the presence of unilateral cleft lip and palate did not affect the maxillary sinus volume, comparing cleft and noncleft patients. A biphasic growth pattern of the maxillary sinus and a presence of sexual dimorphism were found.

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.

Volumetric assessment of paranasal sinus opacification on computed tomography can be automated using a convolutional neural network

BACKGROUND

Computed tomography (CT) plays a key role in evaluation of paranasal sinus inflammation, but improved, and standardized, objective assessment is needed. Computerized volumetric analysis has benefits over visual scoring, but typically relies on manual image segmentation, which is difficult and time-consuming, limiting practical applicability. We hypothesized that a convolutional neural network (CNN) algorithm could perform automatic, volumetric segmentation of the paranasal sinuses on CT, enabling efficient, objective measurement of sinus opacification. In this study we performed initial clinical testing of a CNN for fully automatic quantitation of paranasal sinus opacification in the diagnostic workup of patients with chronic upper and lower airway disease.

METHODS

Sinus CT scans were collected on 690 patients who underwent imaging as part of multidisciplinary clinical workup at a tertiary care respiratory hospital between April 2016 and November 2017. A CNN was trained to perform automatic segmentation using a subset of CTs (n = 180) that were segmented manually. A nonoverlapping set (n = 510) was used for testing. CNN opacification scores were compared with Lund-MacKay (LM) visual scores, pulmonary function test results, and other clinical variables using Spearman correlation and linear regression.

RESULTS

CNN scores were correlated with LM scores (rho = 0.82, p < 0.001) and with forced expiratory volume in 1 second (FEV₁ ) percent predicted (rho = -0.21, p < 0.001), FEV₁ /forced vital capacity ratio (rho = -0.27, p < 0.001), immunoglobulin E (rho = 0.20, p < 0.001), eosinophil count (rho = 0.28, p < 0.001), and exhaled nitric oxide (rho = 0.40, p < 0.001).

CONCLUSION

Segmentation of the paranasal sinuses on CT can be automated using a CNN, providing truly objective, volumetric quantitation of sinonasal inflammation.

Intraoperative Sphenoid Sinus Volume Measurement as an Alternative Technique to Intraoperative Computer Tomography

Isolated sphenoid sinus disease (ISSD) is where there is a group of pathologies characterized by inflammation in one or both sphenoid sinuses. Although computer tomography (CT)-based 3D reconstruction remains the gold standard among noninvasive approaches to ISSD diagnostics, no standardized techniques for direct intraoperative measurements of the sphenoid sinus volume in ISSD patients have been documented. We suggest a novel technique for the intraoperative measurement of the sphenoid sinus volume. Our technique is based on filling the sinus with 0.01% methylene blue solution after an endoscopic endonasal sphenoidotomy. The proposed technique was applied to 40 ISSD patients during surgery. Obtained intraoperative measurements were compared to noninvasive measurements from 3D reconstructions based on preoperative CT scans. Our results demonstrated that the obtained measurements did not exhibit significant differences exceeding 0.4 cm³, with CT-scan-based measurements in 39 out of 40 cases (p < 10⁻⁶, Wilcoxon sign-rank nonparametric test), thus confirming the accuracy of the proposed technique. Disagreements between direct intraoperative and CT-based measurements in a single case have been attributed to the presence of remaining pathological masses in the sinus, which was further confirmed during the secondary check of the operated sinus. Accordingly, we suggest that the agreement between the CT-based and intraoperative volume measurements can be used as an indicator of the successful elimination of all pathological masses from the sinus without having to perform an adequate exposure of the entire sphenoid sinus to reduce intraoperative bleeding. The proposed technique is accurate and does not require the involvement of specialized intraoperative CT scanners and avoids additional radiation exposure for the patient during an additional postoperation CT scan to confirm the success of the surgery.

Sphenoid sinuses: pneumatisation and anatomical variants-what the radiologist needs to know and report to avoid intraoperative complications

PURPOSE

Sphenoid sinuses are pneumatised structures, placed in the body of the sphenoid bone, with highly variable morphology. The strict relationships with vascular and nervous structures determine the importance of their anatomical variants in otorhinolaryngology and neurosurgery; a precise understanding of the complex anatomy and anatomic variations of these structures is pivotal for radiological diagnosis of paranasal sinuses pathology and for surgical planning, to avoid potential complications. Our aim is to describe the anatomical variants of sphenoid sinuses, and to help general radiologists and specialists in endoscopic surgery in becoming familiar with these sensitive anatomical structures.

METHODS

A literature search of PubMed and Embase (Elsevier) databases was performed using the keywords "sphenoid sinus" and "anatomy, "sphenoid sinus" and "anatomic variants", "sphenoid sinus", and "anatomic variations".

RESULTS

We described the anatomical variants of the sphenoid sinuses anatomy, according to their size, shape, degree of pneumatisation, protrusion of anatomical structures into their lumen, superimposition of ethmoid cells (Onodi cells), and presence of accessory septations CONCLUSION: The information provided by this study may help in the identification and description of the anatomical variations of the sphenoid sinuses and their relationship to neurovascular structures.

Evaluation of maxillary sinus volume and surface area in children with β-thalassaemia using cone beam computed tomography

OBJECTIVES

Among children with β-thalassaemia, skeletal changes and abnormalities, such as decreased volume or obliteration of the sinus, result primarily from hypertrophy and expansion of the erythroid marrow due to ineffective erythropoiesis. This study evaluated the volumes and surface areas of the maxillary sinuses of children with β-thalassaemia using cone beam computed tomography (CBCT), and compared these findings with corresponding measurements in age- and sex-matched control children.

METHODS

CBCT images were retrospectively evaluated for 16 children with β-thalassaemia, 19 children with a class I skeletal pattern (class I group), and 18 children with a class II skeletal pattern (class II group). After three-dimensional analyses and segmentation of each maxillary sinus, the volumes and surface areas were calculated.

RESULTS

The volumes and surface areas of the right (p > 0.05 and p > 0.05) and left maxillary sinuses (p > 0.05 and p > 0.05) and SNA angles (p > 0.05) were not significantly different among the groups. The ANB (p < 0.05) and SNGoMe (p < 0.05) angles were significantly greater and the SNB (p < 0.05) angle was significantly smaller in the class II and thalassaemia groups than in the class I group.

CONCLUSION

Children with thalassaemia tended to have lower maxillary sinus volumes and surface areas on both right and left sides, compared to those of children with class I and class II skeletal patterns; however, these differences were not statistically significant. In children with thalassaemia, a large intermaxillary discrepancy (ANB) indicated a tendency toward the class II skeletal pattern.

The Relationships Between Craniofacial Structure and Frontal Sinus Morphology: Evaluation With Conventional Anthropometry and CT-Based Volumetry

The purpose of this study was to investigate the effects of craniofacial structure and nasal septal deviation on frontal sinus morphology 3-dimensionally. This study of anatomy, anthropology, morphology, and radiology included 74 dry skulls as study sample. The craniofacial measurements were made through conventional anthropometric methods by the use of calipers. The nasal septal deviation measurements were done by computerized software on photographs taken from frontal view. Frontal sinus volumes were estimated by the computerized tomography-based volumetry. The relationships between craniofacial structure, nasal septal deviation, and frontal sinus morphology were tested by linear regression and correlation analysis. The analysis of numerical variables and categorical variables within different groups was done by Mann-Whitney U/Kruskal-Wallis, and χ² tests, respectively. There appeared a positive relationship between the dimensions of the frontal sinuses and the maximal cranial length and the nasal height especially on the left side (P < .05). However, after multivariate linear regression model for both factors was created, solely the nasal height kept being a positive factor for frontal sinus size as an independent variable. No statistical relevance was detected between the presence of metopic suture and frontal sinus morphology. Septal deviation itself affected frontal sinus morphometry, but the morphometry did not differ between the deviation side and the opposite side. In conclusion, the cranial structure does not affect the frontal sinus morphology but nasal structure affects. The true influences, among measured craniofacial elements, in relationship with the pneumatization of frontal sinus are appeared to be the nasal structure related.

Pneumosinus Dilatans: An exploration into the association between Arachnoid Cyst, Meningioma and the pathogenesis of Pneumosinus Dilatans

OBJECTIVES

To investigate the association between certain intracranial masses (meningioma and arachnoid cyst) and the incidence of Pneumosinus Dilatans (PSD) - including whether the size of the mass correlates with severity of the condition.

PATIENTS AND METHODS

A review of the available case reports on PSD was performed. Clinical data was extracted from 111 case reports for analysis. A further case-control study was performed using CT Head datasets to investigate the aetiological relationship between intracranial masses and PSD. Cases included patients with confirmed arachnoid cyst or meningioma. Controls included patients with no intracranial masses.

RESULTS

PSD is most common in the frontal (48%) and sphenoid sinuses (43%). Men are twice as likely to be affected as women. 58% of cases occur in patients aged 35 or under. The most common symptoms reported are facial deformities (39%), headache (24%) and visual loss (15%). Unexplained visual changes (e.g. diplopia, reduced visual acuity) are strongly correlated with sphenoid sinus involvement. PSD is more common in patients with skull-base meningioma (OR 5.67) and middle cranial fossa arachnoid cysts (OR 10.00). Mean sinus volume in patients with PSD can increase by up to 4 times.

CONCLUSION

We present the first direct investigation into the relationship between meningioma, arachnoid cyst and Pneumosinus Dilatans. There is a statistical correlation between skull-base meningioma and middle cranial fossa arachnoid cysts and the incidence of PSD. This specific anatomical relation suggests that local factors contribute to the pathogenesis of the condition. Alterations in intracranial pressure due to mass effect or vascular occlusion, in addition to the localised release of bone growth factors (IGF-1, IGF-2, PDGF), are possible mechanisms for this. The first peak in incidence of PSD coincides with the completion of normal sinus pneumatisation, which raises the further possibility that predisposing genetic factors also contribute.

Dynamic Regulation of Level Set Parameters Using 3D Convolutional Neural Network for Liver Tumor Segmentation

Segmentation of liver tumors plays an important role in the choice of therapeutic strategies for liver disease and treatment monitoring. In this paper, we generalize the process of a level set with a novel algorithm of dynamic regulation to energy functional parameters. The presented method is fully automatic once the tumor has been detected. First, a 3D convolutional neural network with dense layers for classification is used to estimate current contour location relative to the tumor boundary. Second, the output 3D CNN probabilities can dynamically regulate parameters of the level set functional over the process of segmentation. Finally, for full automation, appropriate initializations and local window size are generated based on the current contour position probabilities. We demonstrate the proposed method on the dataset of MICCAI 2017 LiTS Challenge and 3DIRCADb that include low contrast and heterogeneous tumors as well as noisy images. To illustrate the strength of our method, we evaluated it against the state-of-the-art methods. Compared with the level set framework with fixed parameters, our method performed better significantly with an average DICE improvement of 0.15. We also analyzed a challenging dataset 3DIRCADb of tumors and obtained a competitive DICE of 0.85 ± 0.06 with the proposed method.

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.

Is it possible to measure hemodynamic changes in the prefrontal cortex through the frontal sinus using continuous wave DOT systems?

The present work shows the capability of near infrared (NIR) light to reach the cerebral cortex through the frontal sinus using continuous-wave techniques (CW-DOT) in a dual study. On the one hand, changes in time during the tracking of a blood dye in the prefrontal cortex were monitored. On the other hand, hemodynamic changes induced by low frequency of transcranial magnetic stimulation applied on the prefrontal cortex were recorded. The results show how NIR light projected through the frontal sinus reaches the cerebral cortex target, providing enough information to have a reliable measurement of cortical hemodynamic changes using CW-DOT.

Increased Accuracy, Confidence, and Efficiency in Anterior Ethmoidal Artery Identification with Segmented Image Guidance

OBJECTIVE

To determine whether using image guidance technology with 3-dimensional image segmentation increases the endoscopic surgeon's accuracy, efficiency, and confidence in identifying the anterior ethmoidal artery.

METHODS

This is a cross-sectional study of attending physicians and residents at an academic medical center. Because identification of the anterior ethmoidal artery during image-guided surgery can be challenging, we studied the effect of anterior ethmoidal artery image segmentation (ie, partitioning and coloring) on surgeon test performance. A computerized test was administered to 16 surgeons who were asked to identify the anterior ethmoidal artery on multiplanar computed tomographic images and to answer multiple-choice questions. Half the questions showed segmented images of the anterior ethmoidal artery, and half showed images without segmentation. Efficiency and accuracy of identification and subjective surgeon confidence were determined for each question. Descriptive statistics were used to compare test performance for identification of the anterior ethmoidal artery on images with or without segmentation.

RESULTS

Percentage of correct answers ( P < .001), efficiency ( P < .001), and confidence ( P < .001) in identification of the anterior ethmoidal artery were significantly better with segmented computed tomographic images.

DISCUSSION

We demonstrated that use of segmented images improves surgeons' accuracy, confidence, and efficiency for identification of the anterior ethmoidal artery.

IMPLICATIONS FOR PRACTICE

We describe how segmentation can allow surgeons to improve the surgical course by increasing their accuracy, confidence, and efficiency in identifying the anterior ethmoidal artery.

Virtual reconstruction of paranasal sinuses from CT data: A feasibility study for forensic application

PURPOSE

The purpose of this study was to report the feasibility of computed modelization and reconstitution of the paranasal sinuses, before and after trauma, from CT data.

MATERIALS AND METHODS

We modeled and reconstructed the paranasal sinuses of two patients (A and B), before and after trauma, using two different softwares (3DSlicer^® and Blender^®). Both patients had different numbers and locations of fractures. The 3DSlicer^® software was used to create a 3D model from CT data. We then imported the 3D data into the Blender^® software, to reconstruct and compare the dimensions of the paranasal sinuses before and after trauma.

RESULTS

The 3 fragments of patient A and the 7 fragments of patient B could be repositioned in the pre-traumatic configuration. Distance measurements proved to be similar between pre- and post-traumatic 3D volumes.

CONCLUSION

After simple trauma, bone facial anatomy reconstruction is manually feasible. The whole procedure could benefit from automatization through machine learning. However, this feasibility must be confirmed on more severely fractured paranasal sinuses, to consider an application in forensic identification.

Impact of Hard Palate Angulation Caused by Septal Deviation on Maxillary Sinus Volume

Objective

To investigate the effect of hard palate angulation caused by septal deviation on the volume of the maxillary sinus.

Methods

Coronal computed tomographic (CT) scans of 1568 patients aged from 18 to 60 were examined. CT scans of 402 patients were included in the study. On these scans, the maxillary sinus volume, the angle of the nasal septal deviation, and the angulation of the hard palate were calculated using the ImageJ software. Each maxillary sinus volume was statistically compared with each other and with those in the control group. Correlations between palatal angulation and septal deviation were determined.

Results

Deviated nasal septum whether with or without deflection of the hard palate was noted to have caused changes in the volume of the maxillary sinus in both female and male patients. The volume of the maxillary sinus on the deviated side was less than that of the opposite side, and the differences between the volumes of both sinuses were statistically significant (p<0.05). No significant differences were noted when compared with the control group. A positive correlation was observed between the nasal septal deviation angle and the angulation of the hard palate.

Conclusion

Regardless of whether or not it affects the hard palate, nasal septal deviation reduces the volume of the maxillary sinus on the deviated side but does not affect the total volume of the maxillary sinuses. Significant differences between the volumes on the two sides can lead to facial asymmetry.

Computed tomography-based volumetric tool for standardized measurement of the maxillary sinus

Volume measurements of maxillary sinus may be useful to identify diseases affecting paranasal sinuses. However, literature shows a lack of consensus in studies measuring the volume. This may be attributable to different computed tomography data acquisition techniques, segmentation methods, focuses of investigation, among other reasons. Furthermore, methods for volumetrically quantifying the maxillary sinus are commonly manual or semiautomated, which require substantial user expertise and are time-consuming. The purpose of the present study was to develop an automated tool for quantifying the total and air-free volume of the maxillary sinus based on computed tomography images. The quantification tool seeks to standardize maxillary sinus volume measurements, thus allowing better comparisons and determinations of factors that influence maxillary sinus size. The automated tool utilized image processing techniques (watershed, threshold, and morphological operators). The maxillary sinus volume was quantified in 30 patients. To evaluate the accuracy of the automated tool, the results were compared with manual segmentation that was performed by an experienced radiologist using a standard procedure. The mean percent differences between the automated and manual methods were 7.19% ± 5.83% and 6.93% ± 4.29% for total and air-free maxillary sinus volume, respectively. Linear regression and Bland-Altman statistics showed good agreement and low dispersion between both methods. The present automated tool for maxillary sinus volume assessment was rapid, reliable, robust, accurate, and reproducible and may be applied in clinical practice. The tool may be used to standardize measurements of maxillary volume. Such standardization is extremely important for allowing comparisons between studies, providing a better understanding of the role of the maxillary sinus, and determining the factors that influence maxillary sinus size under normal and pathological conditions.

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.

Influence of implant number, length, and tilting degree on stress distribution in atrophic maxilla: a finite element study

This study aims to evaluate the stress values, created in peri-implant region as a consequence of loading on fixed hybrid dentures that was planned with different implant numbers, lengths, or tilting angulations. Thirteen three-dimensional (3D) finite element analysis models were generated with four, five, or seven implants (group A, B, and C). Except the distal implants, all implants were modeled at 4.1 mm (diameter) and 11.5 mm (length) in size. Distal implants were configured to be in five different lengths (6, 8, 11.5, 13, and 16 mm) and three different implant inclination degrees (0°, 30°, and 45°). A 150-N load was applied vertically on prosthesis. Released stresses were evaluated comparatively. The lowest von Mises stress values were found in group C, in the 11.5-mm implant model. Tilting the distal implants 30° caused higher stress values. In 45°-tilting implant models, lower stress values were recorded according to the 30°-tilting models. The ideal implant number is seven for an edentulous maxilla. Tilting the implants causes higher stress values. A 45° inclination of implant causes lower stress values according to the 30° models due to a shorter cantilever. The ideal implant length is 11.5 mm.

Robot-assisted endoscope guidance versus manual endoscope guidance in functional endonasal sinus surgery (FESS)

BACKGROUND

Having one hand occupied with the endoscope is the major disadvantage for the surgeon when it comes to functional endoscopic sinus surgery (FESS). Only the other hand is free to use the surgical instruments. Tiredness or frequent instrument changes can thus lead to shaky endoscopic images.

METHODS

We collected the pose data (position and orientation) of the rigid 0° endoscope and all the instruments used in 16 FESS procedures with manual endoscope guidance as well as robot-assisted endoscope guidance. In combination with the DICOM CT data, we tracked the endoscope poses and workspaces using self-developed tracking markers.

RESULTS

All surgeries were performed once with the robot and once with the surgeon holding the endoscope. Looking at the durations required, we observed a decrease in the operating time because one surgeon doing all the procedures and so a learning curve occurred what we expected. The visual inspection of the specimens showed no damages to any of the structures outside the paranasal sinuses.

CONCLUSION

Robot-assisted endoscope guidance in sinus surgery is possible. Further CT data, however, are desirable for the surgical analysis of a tracker-based navigation within the anatomic borders. Our marker-based tracking of the endoscope as well as the instruments makes an automated endoscope guidance feasible. On the subjective side, we see that RASS brings a relief for the surgeon.

The effects of gender and age on forensic personal identification from frontal sinus in a Turkish population

Objectives:

To define the dimensions of the frontal sinus in groups standardized for age and gender and to discuss the reasons and the effects of the variations.

Methods:

Frontal sinus measurements were obtained from paranasal CT scans of 180 males and 180 females in the Radiology Department of Dursun Odabas Medical Center of Yuzuncu Yil University, Van, which is located in Eastern Turkey, between February and March 2016. The width and height of sinuses were measured on a coronal plane, and the anteroposterior length was measured on an axial plane. Volumes were calculated using the Hospital Information Management Systems and Image Archiving and Management System program. The Statistical Package of the Social Science version 13 was used for statistical analyses.

Results:

We determined differences in the frontal sinus measurements of different age groups in a Turkish adult population. Frontal sinus dimensions were usually higher in females and lower in males after 40-49 years of age than their younger counterparts, but the measurements were lower in females and higher in males in 70≤ years of age group than 60-69 years of age. Left frontal sinus was dominant in young age groups but right frontal sinus was dominant in groups 40-49 years of age or older.

Conclusion:

We observed crossing of the measurements between the different age groups, which we could not find clear explanations. The results of such studies may affect forensic identification from frontal sinus measurements.

New algorithm for semiautomatic segmentation of nasal cavity and pharyngeal airway in comparison with manual segmentation using cone-beam computed tomography

INTRODUCTION

Our objectives were to assess reliability, validity, and time efficiency of semiautomatic segmentation using Segura software of the nasal and pharyngeal airways, against manual segmentation with point-based analysis with color mapping.

METHODS

Pharyngeal and nasal airways from 10 cone-beam computed tomography image sets were segmented manually and semiautomatically using Segura (University of Alberta, Edmonton, Alberta, Canada). To test intraexaminer and interexaminer reliabilities, semiautomatic segmentation was repeated 3 times by 1 examiner and then by 3 examiners. In addition to volume and surface area, point-based analysis was completed to assess the reconstructed 3-dimensional models from Segura against manual segmentation. The times of both methods of segmentation were also recorded to assess time efficiency.

RESULTS

The reliability and validity of Segura were excellent (intraclass correlation coefficient, >0.9 for volume and surface area). Part analysis showed small differences between the Segura and manually segmented 3-dimensional models (greatest difference did not exceed 4.3 mm). Time of segmentation using Segura was significantly shorter than that for manual segmentation, 49 ± 11.0 vs 109 ± 9.4 minutes (P <0.001).

CONCLUSIONS

Semiautomatic segmentation of the pharyngeal and nasal airways using Segura was found to be reliable, valid, and time efficient. Part analysis with color mapping was the key to explaining differences in upper airway volume and provides meaningful and clinically relevant analysis of 3-dimensional changes.

Association between frontal sinus morphology and craniofacial parameters: A forensic view

The aim of this study was to evaluate the morphologic structure of the frontal sinuses with postero-anterior cephalometric radiographs in Turkish adolescents and to compare the findings between genders. The study sample consisted of 148 subjects divided into two groups (74 male subjects; mean age: 14.55 ± 1.42 years-74 female subjects; mean age: 14.95 ± 1.80 years). The right and left maximum height and width of the frontal sinus, maxillary width, nasal width, cranial width, antegonial width parameters were measured in 148 postero-anterior cephalometric radiographs. The data were analyzed using independent t and Mann Whitney U test. Spearman correlation analyses were used to evaluate the relationships of the frontal sinus measurements and transversal cephalometric parameters. The mean values of the right and left frontal sinus width, maxillary width, antegonial width, and cranial width were larger in males than females (P < 0.05). The right frontal sinus height were positively correlated with antegonial width (r = 0.243; P < 0.05) and the right frontal sinus width were positively correlated with antegonial width (r = 0.327; P < 0.01) in males. The right frontal sinus width were positively correlated with nasal width (r = 0.244; P < 0.05) and the left frontal sinus width were positively correlated with nasal width (r = 0.231; P < 0.05) in females. Frontal sinuses were unique to each individual due to their morphological structures, and in forensic science, taking advantage of these features was very important for personal identification.

Nasal Septal Deviation and Concha Bullosa - Do They Have an Impact on Maxillary Sinus Volumes and Prevalence of Maxillary Sinusitis?

Background

The aim of the study was to assess if the presence of nasal septal deviation and concha bullosa is connected with the development of sinuses and the incidence of inflammation within them.

Material/Methods

We retrospectively analysed 214 patients who underwent paranasal sinus computed tomography. There were 125 females and 89 males, the mean age being 47.67±16.74 years (range 18–97). Exclusion criteria included: age under 18 years, prior sinonasal surgery and S-shaped septum.

Results

Mean volume of the right maxillary sinus was 17.794 cm³, while for the left one it was 17.713 cm³. Nasal septal deviation was found in 79.9% of computed tomography examinations and concha bullosa was observed in 42.1% of the patients’ examinations. There was an association between the presence of unilateral or dominant concha bullosa and contralateral direction of septal deviation [right-sided (p=0.039), left-sided (p=0.003)]. There was higher incidence of bilateral maxillary sinusitis in patients with septal deviation (p=0.007). Bilateral concha bullosa did not influence the incidence of bilateral maxillary sinusitis (p=0.495). Neither septal deviation (right sided: p=0.962; left-sided: p=0.731), nor unilateral/dominant concha bullosa (right: p=0.512; left: p=0,430) affected the asymmetry in volumes of maxillary sinuses. Bilateral concha bullosa was connected with larger volume of maxillary sinuses (right sinus: p=0.005; left sinus: p=0.048).

Conclusions

Nasal septal deviation, contrary to concha bullosa, has influence on the development of maxillary sinusitis. There is a connection between the presence of concha bullosa and direction of septal deviation. Only bilateral concha bullosa affects maxillary sinus volumes.

The Age-Related Development of Maxillary Sinus in Children

INTRODUCTION

Paranasal sinuses are complex structures and show individual variation. Providing normative values for paranasal sinus size and their changes related to age could be helpful in evaluating the presence of some diseases related to sinonasal region. The purpose of the current study was to investigate the development of maxillary sinuses and evaluate the volume changes according to age and sex by using stereological and ellipsoidal formula methods after that to compare these approaches with each other in children.

MATERIALS AND METHODS

This retrospective volumetric computed tomography (CT) study was carried out on 361 individuals (180 females, 181 males) between 0 and 18 years old (10 females, 10 males in each group, only 14 age group includes 11 males) with no signs of sinus pathology volumetric estimations determined on CT images using point-counting approach of stereological methods and ellipsoid formula by using morphometric data.

RESULTS

Maxillary sinus volume measurements that were obtained using 2 methods were increased with age in both sexes until 16 years old. There was a significant correlation determined between 2 methods (ICC 0.894-1.000 for right and 0.862-0.999 for left maxillary sinus measurements). According to the sex, the right and left mean maxillary sinuses volumes were determined at 8.30 ± 5.19 and 8.57 ± 5.53 cm(3) in male and at 7.60 ± 4.57 and 7.99 ± 4.73 cm(3) in female by using ellipsoid formula respectively. By the stereological method these values were 8.28 ± 5.26, 8.44 ± 5.35 cm(3) and 7.64 ± 4.55, 7.85 ± 4.73 cm(3) respectively. There was no statistically significant difference between the volume of maxillary sinuses with sex and side using both methods.

CONCLUSIONS

This study presents the basic data for studies relative to the development of the maxillary sinus in children according to 2 methods. The current study demonstrated that the point-counting method and ellipsoid formula are both effective in determining volume estimation of maxillary sinuses and are well suited for CT studies.

Incidental paranasal sinusitis on routine brain magnetic resonance scans: association with atherosclerosis

BACKGROUND

Incidental paranasal sinusitis (IPS) is common on imaging for non-sinusitis disorders, usually without symptoms or obstructive features, and possibly arising from periodontitis (PD). PD associations with atherosclerosis have been widely reported. We test if IPS may also be associated with atherosclerosis.

METHODS

IPS was scored retrospectively in a random sample of 180 magnetic resonance (MR) brain scans and compared with chart review for atherosclerosis (all subtypes), rhinosinusitis, and related factors (smoking, asthma, and relevant surgery). IPS was scored out of 30, from all sinuses, with maxillary sinuses weighted double volumetrically. Significant IPS (Sig IPS) was designated as 6 or more out of 30. Bivariate logistic regression was used to test for associations of Sig IPS to the clinical data, with multivariate analysis then testing for potential confounders.

RESULTS

A total of 173 subjects were analyzed (7 exclusions). MR indications included suspected acute/prior stroke (22.0%). Sig IPS found in 20 (11.6%). Positive histories for atherosclerosis were cerebral, 57 (32.9%); coronary, 48 (27.7%); and peripheral arterial disease, 14 (8.1%). IPS ≥6 was strongly associated with cerebrovascular disease (odds ratio [OR] 6.0, p < 0.001), and less robustly to smoking (OR 2.9, p = 0.07) and rhinosinusitis (OR 2.4, p = 0.09). No associations with coronary or peripheral artery diseases were found. After controlling for smoking and rhinosinusitis, yielding significant subclinical sinusitis, the link of Sig IPS to cerebrovascular disease persisted (modified OR 5.2, p = 0.002).

CONCLUSION

Significant incidental sinusitis, which is mostly subclinical sinusitis, is associated with cerebrovascular disease but not other atheroscleroses. This suggests possible common causation of both by PD.

Paranasal sinus opacification-to-pneumatization ratio applied as a rapid and validated clinician assessment

BACKGROUND

The utility of clinician-applied instruments, particularly the Lund-Mackay score, in the assessment of paranasal sinus computed tomography (CT) in chronic rhinosinusitis (CRS) remains incompletely defined. The purpose of this study was to determine if a new approach to the evaluation of sinus CT could accurately predict the extent of opacification while remaining simple for clinician use.

METHODS

Twenty-four sinus CT scans were measured for the percent of sinus opacification using three-dimensional (3D) volumetric analyses. The same scans were also evaluated using the Lund-Mackay score to measure opacification and the Assessment of Pneumatization of the Paranasal Sinuses (APPS) score to measure total sinus volume (TSV). Correlation analysis was performed for the Lund-Mackay to APPS score ratio as a predictor of percent opacification. Validation analysis was also performed to determine the optimal orientation for Lund-Mackay scoring, which has not previously been described.

RESULTS

The Lund-Mackay to APPS score ratio was very strongly correlated with the percentage of sinus opacification measured by 3D volumetric analysis (r = 0.862, r² = 0.743, p < 0.001). Lund-Mackay scoring was not statistically different between axial-only, coronal-only, or triplanar groups for interrater (p = 0.379) and intrarater reliability (p = 0.312).

CONCLUSION

The Lund-Mackay score is validated for rater reliability in multiple orientations. Using the APPS score as a measure of TSV, the Lund-Mackay-to-APPS ratio very strongly correlates with the percentage of sinus opacification by 3D volumetric analysis. Further study will be required to determine if this ratio is predictive of symptom severity.

Computed tomography based forensic gender determination by measuring the size and volume of the maxillary sinuses

PURPOSE

Identification of human body or remains after death is a forensic procedure, which is difficult to perform and is mandatory by law and in compliance with social norms. Sexing the recovered human remains is an integral part of the identification process. Maxillary sinus can be used for gender determination as it remains intact even when the skull and other bones may be badly damaged in casualties where the body is incinerated. Computed tomography (CT) provides an excellent method for examining maxillary sinuses.

MATERIALS AND METHODS

CT images were used to measure the mediolateral, superoinferior, and anteroposterior dimensions and the volume of the maxillary sinuses in 30 patients (15 males and 15 females) to investigate whether these parameters could be used to determine the gender of an individual for forensic identification. The t-test for independent samples was used to compare these values in males and females and the data were subjected to discriminative analysis using SPSS software.

RESULTS

Our method was able to predict the gender with an accuracy of 80.0% in males and 86.7% in females, with an overall accuracy rate of 83.3%.

CONCLUSION

The accuracy rate in this study was comparable, if not higher than many other methods that have been used to predict the gender of an individual from skeletal remains. The length, width, height, and volume of the maxillary sinuses together with other bones could be used for gender determination with a fair degree of accuracy when the whole skeleton is not available.

The classification of frontal sinus pneumatization patterns by CT-based volumetry

PURPOSE

We aimed to define the classification of frontal sinus pneumatization patterns according to three-dimensional volume measurements.

METHODS

Datasets of 148 sides of 74 dry skulls were generated by the computerized tomography-based volumetry to measure frontal sinus volumes. The cutoff points for frontal sinus hypoplasia and hyperplasia were tested by ROC curve analysis and the validity of the diagnostic points was measured.

RESULTS

The overall frequencies were 4.1, 14.2, 37.2 and 44.5 % for frontal sinus aplasia, hypoplasia, medium size and hyperplasia, respectively. The aplasia was bilateral in all three skulls. Hypoplasia was seen 76 % at the right side and hyperplasia was seen 56 % at the left side. The cutoff points for diagnosing frontal sinus hypoplasia and hyperplasia were '1131.25 mm(3)' (95.2 % sensitivity and 100 % specificity) and '3328.50 mm(3)' (88 % sensitivity and 86 % specificity), respectively.

CONCLUSIONS

The findings provided in the present study, which define frontal sinus pneumatization patterns by CT-based volumetry, proved that two opposite sides of the frontal sinuses are asymmetric and three-dimensional classification should be developed by CT-based volumetry, because two-dimensional evaluations lack depth measurement.

Maxillary Sinus Aeration in Allergic Rhinitis

OBJECTIVE

We aimed to investigate the relationship between allergic rhinitis, which is an important reason of nasal obstruction, and maxillary sinus aeration.

PATIENTS AND METHODS

Three hundred fifteen patients who have a complaint of nasal obstruction and scheduled to undergo skin prick test (SPT) with a suspicion of allergic rhinitis (AR) were enrolled for this study. Thirty-two patients with positive SPT result and 30 patients with a negative SPT result were determined as group 1 and 2 (control group), respectively. A 3-dimensional reconstruction of computed tomography images of the 62 patients was used to assess and calculate maxillary sinus volumes (MSVs).

RESULTS

Total maxillary sinus volumes were measured as 21.87 cm(3) and 30.15 cm(3) in group 1 and group 2, respectively. A statistically significant difference was observed between the MSVs of the groups (P < 0.001).

CONCLUSION

Total maxillary sinus volumes were found to be significantly smaller for patients with a positive SPT compared to patients with a negative SPT. Thus, we may conclude that AR has a negative impact on maxillary sinus aeration.

Two- and three-dimensional anatomy of paranasal sinuses in Arabian foals

The 2- and 3-dimensional (3D) anatomy and the morphometric properties of the paranasal sinuses of the foal have received little or no attention in the literature. The aim of this study was to obtain details of the paranasal sinuses using multiplane CT imaging to create 3D models and to determine morphological and morphometric data for the sinuses using the 3D models. The heads of five female foals were used in this study. The heads were scanned using computed tomography (CT) in the rostrocaudal direction. After the heads had been frozen, anatomical sections were obtained in the scan position. The 3D models of sinuses and the skull were prepared using MIMICS^®. These models were used to assess the surface area and volume of the sinuses, the width, height and orientation of the apertures connecting these sinuses and finally the planar relation of the sinuses with the skull. The right and left sides of all anatomical structures, except the sphenoid sinuses, had symmetric organization on CT images and anatomical sections. The total sinus surface area and volume on both sides were 214.4 cm² and 72.9 ml, respectively. The largest and the smallest sinuses were the frontal sinus (41.5 ml) and the middle conchal sinus (0.2 ml), respectively. It was found that the planes bounding the sinuses passed through easily palpable points on the head. In conclusion, 3D modeling in combination with conventional sectional imaging of the paranasal sinuses of the foal may help anatomists, radiologists, clinicians and veterinary students.

Using semi-automated segmentation of computed tomography datasets for three-dimensional visualization and volume measurements of equine paranasal sinuses

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three-dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2-25 years, were analyzed by the use of separate semi-automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi-automated segmentation of CT-datasets improved understanding of this anatomically challenging region.

The effect of nasal septal deviation on maxillary sinus volumes and development of maxillary sinusitis

OBJECTIVES

The purpose of this study was to determine the possible role of nasal septal deviation on volume of maxillary sinuses and its relationship with development of maxillary sinusitis.

MATERIALS AND METHODS

Between May 2010 and September 2012, paranasal sinus computed tomography (CT) findings of 825 patients (470 males, 355 females), who admitted to Ear Nose and Throat Department of Bozok University Medical Faculty were retrospectively analyzed. By excluding the other co-existent sino nasal pathologies, 109 consecutive patients (47 males, 62 females mean age 36 ± 13.4 years; range 18-71 years) with isolated nasal septal deviations were recruited for the study. The convex side of the septal curvature was accepted as the direction of deviation. The findings were grouped according to the radiologically measured angle of nasal septal deviations. The deviation angle of the nasal septum was described as; mild (<9°), moderate (the angle between 9° and 15°), or severe (15° and up). The volume of each maxillary sinus (ipsi- and contralateral to the deviation side) was also calculated using the computer program. Sinusitis was defined as any evident thickening of the maxillary sinus mucosa.

RESULTS

There were 62 females and 47 males with a mean age of 36 ± 13.4. Nasal septal deviation angles were found to range between 5° and 27.2° (mean 13° ± 3.4°). The right sided deviations included 19 mild (<9°, Group I), 16 moderate (9°-15°, Group II), and 16 severe (15° and up, Group III) cases. The left sided deviations included 19 mild (<9°, Group I), 19 moderate (9°-15°, Group II), and 20 severe (15° and up, Group III) subjects. Maxillary sinus volumes were compared between right and left sided deviation groups. We could not demonstrate a statistically significant difference between the right maxillary sinus volumes of Groups I and II in left sided deviation cases (p = 0.77). In the same side, comparison of Groups I-III and Groups II-III, the maxillary sinus volume differences were found to be significantly meaningful (p = 0.001 and p = 0.013, respectively). Identical results were yielded in the right sided septal deviation group related to the maxillary sinus volumes of Groups I and II and Groups I-III and Groups II-III compartments (p = 0.99, p = 0.004 and p = 0.003, respectively). In both right and left deviation groups, ipsi and contralateral maxillary sinus volume comparements produced statistically significant results (p = 0.002 and p = 0.04, respectively). The presence of maxillary sinusitis findings were significantly increased in both group (p = 0.00). Statistical significance was set at p < 0.05.

CONCLUSION

Our findings suggest that maxillary sinus volumes tend to be higher at the contralateral side of the severe septum deviations. In addition, the chance of finding maxillary sinusitis findings on ipsilateral to the severe septum deviation was significantly increased.