Paranasal Sinus Computed Tomography Images Research Articles

The accuracy of deep learning models for diagnosing maxillary fungal ball rhinosinusitis.

To assess the accuracy of deep learning models for the diagnosis of maxillary fungal ball rhinosinusitis (MFB) and to compare the accuracy, sensitivity, specificity, precision, and F1-score with a rhinologist. Data from 1539 adult chronic rhinosinusitis (CRS) patients who underwent paranasal sinus computed tomography (CT) were collected. The overall dataset consisted of 254 MFB cases and 1285 non-MFB cases. The CT images were constructed and labeled to form the deep learning models. Seventy percent of the images were used for training the deep-learning models, and 30% were used for testing. Whole image analysis and instance segmentation analysis were performed using three different architectures: MobileNetv3, ResNet50, and ResNet101 for whole image analysis, and YOLOv5X-SEG, YOLOv8X-SEG, and YOLOv9-C-SEG for instance segmentation analysis. The ROC curve was assessed. Accuracy, sensitivity (recall), specificity, precision, and F1-score were compared between the models and a rhinologist. Kappa agreement was evaluated. Whole image analysis showed lower precision, recall, and F1-score compared to instance segmentation. The models exhibited an area under the ROC curve of 0.86 for whole image analysis and 0.88 for instance segmentation. In the testing dataset for whole images, the MobileNet V3 model showed 81.00% accuracy, 47.40% sensitivity, 87.90% specificity, 66.80% precision, and a 67.20% F1 score. Instance segmentation yielded the best evaluation with YOLOv8X-SEG showing 94.10% accuracy, 85.90% sensitivity, 95.80% specificity, 88.90% precision, and an 89.80% F1-score. The rhinologist achieved 93.5% accuracy, 84.6% sensitivity, 95.3% specificity, 78.6% precision, and an 81.5% F1-score. Utilizing paranasal sinus CT imaging with enhanced localization and constructive instance segmentation in deep learning models can be the practical promising deep learning system in assisting physicians for diagnosing maxillary fungal ball.

The Effects of Nasal Septal Deviation on Anterior Skull Base Parameters.

Introduction Functional endoscopic sinus surgery and endoscopic skull base surgery are frequently performed surgeries today. Nasal septal deviation is a common finding and can affect the surgical area. Therefore, it is important to examine the effect of this deviation on other anatomical structures. Objectıve The aim of the present study was to determine whether there is a relationship between the degree of nasal septal deviation and anterior skull base structures using computed tomography (CT). Methods A total of 312 patients (aged 18 to 65 years old) whose paranasal sinus CT images were available were included in the study. Measurements were obtained on images retrieved from Picture Archiving and Communication System (PACS) and Horos image archive systems in the bone window in the coronal and axial plane. Results The mean age of 312 patients was 33.00 years old (standard deviation [SD] 11.22 years). The presence of septal deviation was not associated with changes in olfactory fossa (OF) depths, Keros degrees, and the angle between the lateral lamella and the cribriform lamella. However, OF depths and Keros degrees on the deviated side of the septum were found to change at a significant level ( p < 0.05). No significant association was observed between the degree of septal deviation and cribriform lamella-lateral lamella angle. Conclusion The study showed significantly increased OF depth and Keros degree on the deviated side of the nasal septum. Performing CT scans before endoscopic sinus surgery and endoscopic skull base surgery is important to increase the chances of a successful surgical outcome and to reduce complications.

Pneumatization of the sphenoid sinus is the major factor determining the variations of adjacent vital structures

BackgroundSphenoid sinus (SS) is an important landmark for endoscopic sinus surgery (ESC) and endoscopic skull base surgery. This study examines the relation of the extent of pneumatization of the sphenoid sinus with adjacent vital structures such as the internal carotid artery, optic canal, and Vidian nerve by using paranasal sinus computed tomography (PNSCT).MethodsThe study was designed retrospectively. PNSCT images in axial, coronal, and sagittal planes on both sides (right, R; left, L) were examined for sphenoid sinus, Vidian canal (VC), optic canal (OC), and carotid canal (CC) bilaterally.ResultsThe carotid canal did not show identification on the SS wall in females compared to males bilaterally (right, p= 0.002 and left, p= 0.002). The mean age was significantly higher in patients with a presellar type of sphenoid sinus (p=0.003). The mean age was significantly lower on the right side with a VC completely within the sphenoid sinus (p=0.005). The mean age of patients with an optic canal protrudation to the SS wall was significantly higher than patients with an optic canal indentation to the SS wall (p= 0.007). On the left side, cases with an optic canal protruding to the SS wall were older than cases with an optic canal indentation to the SS wall (p= 0.008). SS variations on the sagittal plane were significantly correlated with RVC, RCC, LVC, and LCC variations. Also, SS variations on the coronal plane were significantly related to types of LVC and RVC.ConclusionsPneumatization of SS significantly affects the development of surrounding vital structures, especially with increasing age.

Imaging of the Ethmomaxillary Sinus, its Prevalence, and Evaluation of its Relationship with Chronic Rhinosinusitis

Objective: The presence of an ethmomaxillary sinus (EMS) may increase the susceptibility to inflammatory paranasal sinus diseases such as chronic rhinosinusitis (CRS) and cause difficulties in surgical interventions to the paranasal sinuses. Therefore, this study aimed to examine the EMS in patients with and without CRS. Methods: The study included 150 patients (300 sides) diagnosed with CRS by the ear–nose–throat clinic and 151 individuals (302 sides) without CRS. Paranasal sinus computed tomography images were reviewed retrospectively. The presence of an EMS (bilateral or not) and its relationship with age and sex were examined. The severity of CRS was determined with the Lund–Mackay scoring system, and its relationship with EMS was evaluated. Results: The EMS was detected in 7 patients (7/301, 2.32%) and 9 sides (9/602, 1.49%) of 301 patients (602 sides) included. The incidence in the CRS group was 2.6%. Three cases were unilateral, and one was bilateral. The incidence in the control group was 1.98%, two cases were unilateral, and one was bilateral. According to the Lund–Mackay scoring system, the mean CRS severity was 8.62 (±5.47). Its severity was 5.25 (±3.94) in the EMS group and 8.71 (±5.48) in the non-EMS group. Conclusion: No statistically significant difference was found between the groups with and without CRS in terms of the presence of EMS (p = 0.723). No evidence reveals that EMS increased the severity of CRS.

Maxillary sinus volume and adenoid tissue size in children: computed tomographic evaluation

Abstract OBJECTIVES. Adenoid hypertrophy is related to obstructive sleep apnea syndrome (OSAS). In this study, we investigated the relationship between adenoid tissue size and maxillary sinus volumes by examining the paranasal sinus computed tomography (PNSCT) images. MATERIAL AND METHODS. PNSCT images of 41 children were included in this study. According to the adenoid/nasopharynx (A/NP) ratio, two groups were identified. Group 1 (n=19, 9 males and 10 females): A/NP≤0.50 and Group 2 (n=22, 16 males and 6 females): A/NP&gt;0.50. The following measurements were performed: adenoid width, NP width, A/NP ratio, air column, soft palate, maxillary sinus volume and mucosal thickening. RESULTS. Adenoid width of group 2 (16.11±2.26 mm) was higher than that of group 1 (10.97±2.26 mm). In group 2, with an A/NP ratio of 0.61±0.07, the air column value (6.30±2.27 mm) was lower than that of group 1 with an A/NP ratio of 0.40±0.07 (air column value: 10.06±3.78 mm). NP width, soft palate and maxillary sinus volumes were not different between groups 1 and 2. As the adenoid width increased, the A/NP ratio increased, and the air column decreased. CONCLUSION. The increase of the A/NP ratio was related to the decreased air column. In older children, air column and bilateral maxillary sinus volumes increased. In males, the adenoid width value was larger than that in females. There was no significant relationship between A/NP ratio and maxillary sinus volume or NP width values. However, higher A/NP ratio values were related to lower air column measurements.

Assessment of the prelacrimal recess in different maxillary sinus pneumatizations in relation to endoscopic prelacrimal recess approaches: a computed tomography study.

To assist in planning before the endoscopic prelacrimal recess (PLR) approach, we aimed to investigate the relationship between morphometry and variations of PLR in maxillary sinus (MS) pneumatizations. Retrospective analysis of the paranasal sinus computed tomography images of 150 patients was conducted to determine the pneumatization patterns of the MS, PLR variations, and the applicability of the PLR approach. The results were compared based on lateralization, gender, and age groups. The PLRwidth, the anteroposterior diameter of the nasolacrimal duct (NLD), the vertical and horizontal diameters of the MS were the highest in hyperplasic MS, and decreased significantly with increasing age (p = 0.005, p = 0.017, p = 0.000), respectively. Most of the morphometric measurements were higher in hyperplasic MS, while the medial wall thickness of PLR was higher in hypoplasic MS. The PLRwidth for feasibility of the PLR approach were Type I (48%) in hypoplasic MS and Type III (80%) in hyperplasic MS (p < 0.001), respectively. The PLR medial wall thickness was higher in Type I, while the piriform aperture angle (PAA), MS volume, length, and slope of the NLD were higher in Type III PLRwidth (p = 0.000), respectively. The highest anterior and separation-type variations of the PLR were observed in hyperplasic MS, whereas 31.0% of hypoplasic MS had no PLR (p < 0.001). This study revealed that PLRwidth and PAA were the highest in hyperplasic MS, which allows the endoscopic PLR approach to be performed more easily. For safer and uncomplicated surgery, surgeon should be aware of the PLR anatomy in different MS pneumatization patterns.

Relationship Between Nasal Septal Deviation Angles and Turbinates: A Computed Tomography Study.

Background This study aimed to evaluate inferior turbinate hypertrophy caused by nasal septum deviation, nasal septal deviation (SD) angles, and age differences with the help of paranasal computed tomography (CT) and to investigate the relationship between these parameters. Methodology The paranasal sinus CT images of 100 patients (50 males and 50 females) were retrieved from the hospital's picture archiving and communication system. In this retrospective study, patients were examined in two groups. There were 50 patients aged >35 years in group 1 and 50 patients aged <35 years in group 2. The SD side was determined using a coronal image and was mentioned as the ipsilateral side. The contralateral side of the SD side was mentioned as the contralateral side. Additionally, the SD curve angle (SDCA), superior SD angle (SSDA), and diameters and mucosal thicknesses of the inferior turbinates were measured. Concomitant ipsilateral sinusitis and ipsilateral concha bullosa (in the middle concha) were also noted as present or absent. Results In our study, the SDCA values of the ≥35-year age group were significantly higher than those of the <35-year age group (p < 0.05). Furthermore, the SSDA values of the ≥35-year age group were significantly lower than those ofthe <35-year age group (p < 0.05). In each of the age groups, ipsilateral inferior turbinate mucosal thickness and ipsilateral inferior turbinate diameter values were significantly higher than those of the contralateral sides (p < 0.05). Ipsilateral concha bullosa was present in 30.0% of the <35-year age group and 18.0% of the ≥35-year age group.Ipsilateral sinusitis was present in 34.0% of the <35-year age group and 52.0% of the ≥35-year age group. Conclusions SD and inferior turbinate hypertrophies should be evaluated together and measured with paranasal CT to provide more efficient nasal aeration. Studies with larger patient series are needed to elucidate the etiology.

Maxillary sinus volume and mucosal thickening according to the septal deviation angle and age of the children.

We examined the relationship between nasal septal deviation (SD) angle and maxillary sinus volumes by examining the paranasal sinus computed tomography (PNSCT) images in children. In this retrospective study, PNSCT images of 106 children with one-sided nasal SD were included. According to the SD angle, two groups were identified: Group 1 (n = 54): SD angle ≤ 11°, Group 2 (n = 52): SD angle > 11°. There were 23 children between 9 and 14 years and 83 children between 15 and 17 years. Maxillary sinus volume and mucosal thickening were evaluated. In 15- to 17-year age group, maxillary sinus volumes of males were higher than females bilaterally. For each of the males and females, ipsilateral maxillary sinus volume was significantly lower than the contralateral side in all children and in 15- to 17-year age group. In each of the SD angle values (≤11 or >11) separately, ipsilateral maxillary sinus volume was lower; and in the SD angle > 11° group, maxillary sinus mucosal thickening values were higher than those of the contralateral side. In young children in 9- to 14-year age group, bilateral maxillary sinus volumes decreased, in this group maxillary sinus volume was not affected according to the SD. However, in 15- to 17-year age groups, maxillary sinus volume was lower on the ipsilateral SD side; and ipsilateral and contralateral maxillary sinus volumes of the males were significantly higher than those in the females. SD should be treated at an appropriate time to prevent SD-related maxillary sinus volume shrinkage and rhinosinusitis.

Supraorbital ethmoid cells (SOECs), anterior ethmoid artery notch and ethmoid roof relation in PNSCT

ObjectivesWe investigated supraorbital ethmoid cell (SOEC) presence and types in paranasal sinus computed tomography (PNSCT). MethodsThe PNSCT images of 188 adult patients (93 males and 95 females) were evaluated as SOEC group (n = 87 sides), and non-SOEC group (n = 289 sides, control). In both groups, anterior ethmoid artery (AEA) notch-ethmoid roof distance and presence of AEA canal were evaluated. In the SOEC group, SOEC types (type 1 to 3) and SOEC angle are also examined. ResultsSOEC was detected in 87 sides (23.13 %). SOEC type 2 was the most detected type (71.3 %). AEA notch-ethmoid roof distance of the SOEC group was significantly higher than those in the non-SOEC group. AEA notch-ethmoid roof distance of the SOEC Type 3 group was significantly higher than SOEC Type 2 group. AEA notch-ethmoid roof distance was 3.74 ± 1.81 mm in the SOEC group and 0.68 ± 1.16 mm in the non-SOEC group. When SOEC types were considered, this distance was 5.29 ± 2.66 mm in type 3, 3.35 ± 1.35 mm in type 2 and 3.48 ± 0.92 mm in type 1. In higher SOEC types, SOEC angle; and AEA notch-ethmoid roof distance increased. ConclusionIn more pneumatized SOEC presence, SOEC angle increase, and AEA notch-ethmoid roof distance increases, AEA runs inferiorly in the ethmoid cells and freely below the skull base; and is more susceptible to injury. The surgeons should be more careful not to damage AEA in the FESS when detecting well-pneumatized SOECs (SOEC Type 3).

Assessment of low-dose paranasal sinus CT imaging using a new deep learning image reconstruction technique in children compared to adaptive statistical iterative reconstruction V (ASiR-V)

PurposeTo compare the effects of deep learning image reconstruction (DLIR) and adaptive statistical iterative reconstruction V (ASiR-V) on image quality in low-dose computed tomography (CT) of paranasal sinuses in children.MethodsLow-dose CT scans of the paranasal sinuses in 25 pediatric patients were retrospectively evaluated. The raw data were reconstructed with three levels of DLIR (high, H; medium, M; and low, L), filtered back projection (FBP), and ASiR-V (30% and 50%). Image noise was measured in both soft tissue and bone windows, and the signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the images were calculated. Subjective image quality at the ethmoid sinus and nasal cavity levels of the six groups of reconstructed images was assessed by two doctors using a five-point Likert scale in a double-blind manner.ResultsThe patients’ mean dose-length product and effective dose were 36.65 ± 2.44 mGy·cm and 0.17 ± 0.03 mSv, respectively. (1) Objective evaluation: 1. Soft tissue window: The difference among groups in each parameter was significant (P < 0.05). Pairwise comparisons showed that the H group’ s parameters were significantly better (P < 0.05) than those of the 50% post-ASiR-V group. 2. Bone window: No significant between-group differences were found in the noise of the petrous portion of the temporal bone or its SNR or in the noise of the pterygoid processes of the sphenoids or their SNRs (P > 0.05). Significant differences were observed in the background noise and CNR (P < 0.05). As the DLIR intensity increased, image noise decreased and the CNR improved. The H group exhibited the best image quality. (2) Subjective evaluation: Scores for images of the ethmoid sinuses were not significantly different among groups (P > 0.05). Scores for images of the nasal cavity were significantly different among groups (P < 0.05) and were ranked in descending order as follows: H, M, L, 50% post-ASiR-V, 30% post-ASiR-V, and FBP.ConclusionDLIR was superior to FBP and post-ASiR-V in low-dose CT scans of pediatric paranasal sinuses. At high intensity (H), DLIR provided the best reconstruction effects.

Effect of treatments for head and neck cancer on sinus shadow on computed tomography

ObjectiveHead and neck surgeries may cause changes in the nasal airflow, and radiotherapy irreversibly damages paranasal sinus epithelial cells. Some chemotherapeutic drugs have been reported to negatively affect airway ciliary activity in mice, and chronic rhinosinusitis could be an adverse effect of head and neck cancer (HNC) treatment. To evaluate whether HNC treatment is a risk factor for developing sinonasal mucosal thickening that may reflect paranasal sinus inflammation, we compared pre- and post-treatment paranasal sinus computed tomography (CT) images of patients treated for HNC at a single university hospital. MethodsThe patients who received curative treatment for HNC (oral, pharyngeal, and laryngeal cancers) and started receiving first-line therapy between January 2015 and December 2019 were included. Data on age, sex, primary lesion, clinical stage, treatment, smoking history, drinking history, comorbidities (diabetes and chronic lung disease), and pre- and post-treatment (three months and one year after the final treatment) paranasal sinus CT images were analyzed from medical records. Pre- and post-treatment paranasal sinus CT images were scored using the Lund–Mackay (LM) staging system. ResultsIn total, 245 patients participated in this study. Three months after the final treatment, 80.4% of patients had no change in their total LM scores (p=0.621). Almost 80% of patients who underwent total laryngectomy also had no change in their total LM scores (p=0.833). One-third of patients with nasopharyngeal cancer (NPC) had worse LM scores after treatment (5/15), although no significant difference was observed (p=0.171). None of the various factors collected were significantly related to changes in LM scores three months after the completion of treatment. One year after the final treatment, 211 patients were included and no significant changes in the pre-and post-LM scores were observed in the same analyses, while changes in LM scores were significantly different between T categories (T1-2 vs. T3-4) (p=0.020). ConclusionWe found no significant changes in the LM scores after HNC treatment in all the patients, which implies that HNC treatment may not be an apparent risk factor for sinonasal mucosal inflammation.

ORTA ANADOLU'DA KRONİK RİNOSİNÜZİTİN BİREYSEL ÖZELLİKLER VE ÇEVRESEL FAKTÖRLERLE İLİŞKİSİ

OBJECTIVE: The aims of this study were to investigate the prevalence and distribution of sinonasal diseases in patients that underwent paranasal sinus computed tomography (CT) due to chronic rhinosinusitis (CRS) with or without nasal polyps, and to explore the association between CRS and sinonasal variations and the effect of environmental factors.MATERIAL AND METHODS: The paranasal sinus CT images and files of 1000 patients that referred to a tertiary health center in Ankara were retrospectively evaluated. The CT findings, smoking status, presence of allergies, place of residence (urban/rural), and history of functional endoscopic sinus surgery were noted.RESULTS: CRS was seen in 68% of the patients, and most common in maxillary sinuses (53%). Nasal polyps with CRS were noted in 11% of the cases. CRS was also more common among smokers (p&amp;lt;0.001). In CRS accompanied by nasal polyps, no difference was found between urban and rural residence. However, most cases of CRS with nasal polyps lived in urban areas (81.4%, p=0.006). There was no difference between allergy and CRS with and without nasal polyps or between sinonasal variations and CRS development.CONCLUSIONS: In the region investigated, the prevalence of CRS with nasal polyps was higher in the urban area (higher air pollution); however, the prevalence of CRS without nasal polyps did not change according to the place of residence. CRS was generally more common among smokers, but there was no significant difference in patients with CRS accompanied by nasal polyps. CRS was not more common in people with allergies.

The relationship between nasal septal deviation and anatomical variations of the paranasal sinus

Objectives: The aim of this study was to determine the relationship between septum deviation and anatomic variations of the paranasal sinus. Methods: A total of 157 (79 males, 78 females) patients between the ages of 17 and 77 years (mean age: 33.7 ± 14.9 years) were included in the study. Using paranasal sinus computed tomography imaging, anatomical variations including nasal septal deviation, Agger nasi cells, Haller cells, Onodi Cells, sphenoid sinus pneumatisation, paradoxical middle turbinates, middle turbinate pneumatisation, maxillary sinus septa,vertical septa in the sphenoid sinus, optic nerve dehiscenceand cribriform plate lamina lateralis height were evaluated. Results: Agger nasi cells were present in 47.1% of cases, Haller cells were seen in 5% of cases and Onodi cells were observed in 23.6% of cases. In 70.1% of cases, one vertical septa in the sphenoid sinus was observed. Maxillary sinus septa was observed in 16.5% of cases. There was a significant negative correlation between the female gender and increased sphenoid sinus pneumatisation (p = 0.035). There was a positive correlation between maxillary sinus septa and the presence of Onodi cells (pright =0.045, pleft = 0.017). There was also a negative correlation between maxillary sinus septa and sphenoid sinus pneumatisation (pright = 0.001, pleft = 0.005). Conclusions: In our study, we found that maxillary sinus septa, Agger nasi, Haller cells, cribriform plate lamina lateralis height, sphenoid sinus septation and Onodi cells were interrelated. We recommend that surgeons evaluate patients with these variations to prevent complications.

Combination of the endoscopic septonasal flap technique and bioabsorbable steroid-eluting stents for repair of congenital choanal atresia in neonates and infants: a retrospective study

BackgroundMultiple surgical approaches have been proposed to repair the congenital choanal atresia. However, there remains no general consensus about the optimal surgical technique. This study aimed to describe and evaluate outcomes of the endoscopic septonasal flap technique combined with bioabsorbable steroid-eluting stents for repair of congenital choanal atresia in neonates and infants.MethodsClinical data of 37 neonates and infants with congenital choanal atresia who received nasal endoscopic surgery with the flap technique between January 2018 and July 2020 were analyzed retrospectively. All patients underwent the ultra‑low‑dose paranasal sinus computed tomography imaging preoperatively to confirm diagnosis and plan the surgery. In these patients, the mirrored L-shaped flap technique was performed for bilateral atresia and the cross-over L-shaped flap technique was performed for unilateral atresia. A total of 22 patients had silicone stents postoperatively and 15 patients had bioabsorbable steroid-eluting stents postoperatively. Silicone stents were removed at one month postoperatively under secondary general anesthesia, while no anesthesia was needed to remove the bioabsorbable steroid-eluting stents. Postoperative follow-up ranged from 10 months to 3 years.ResultsThe septonasal flap technique was performed in all patients. Compared with the silicone stents group, the average operative duration and the hospital length of stay in the bioabsorbable steroid-eluting stents group were decreased [(97.46 ± 15.37) min vs (83.49 ± 19.16) min t = 13.733, P < 0.001] [(12.8 ± 3.22) d vs (7.67 ± 3.91) d t = 15.082, P < 0.001], the average number of procedures was reduced [(2.04 ± 0.64) vs (1.00 ± 0.00), t = 82.689, P < 0.001], the differences were statistically significant. There were no reports of postoperative restenosis and complications in the bioabsorbable steroid-eluting stents group, and follow-up endoscopic examinations showed patency and stable nasal passages in all cases.ConclusionsThe endoscopic septonasal flap technique can effectively expose and expand the choanal bony structure for repair of congenital choanal atresia in neonates and infants. The combined use of this technique along with bioabsorbable steroid-eluting stents can help prevent the need for revision procedures and also against stent-related injuries.

Olfactory Fossa and New Angle Measurements: Lateral Lamella-Cribriform Plate Angle.

The authors investigated the olfactory fossa (OF) in patients with unilateral nasal septal deviation (NSD) and presented the lateral lamella-cribriform plate angle (LLCPA). Paranasal sinus computed tomography images of 300 adult subjects with unilateral NSD (111 males, 189 females) were evaluated retrospectively. Septal deviation angle (SDA), Keros Classification, OF depth and width, LLCPA; and orbital plate and cribriform plate (OPCP) distance were measured. The OF depth values (ipsilateral, contralateral) were found as Keros III >Keros II >Keros I (Padjusted <0.0175). The OF width values (ipsilateral) were detected as Keros I >Keros II and Keros I >Keros III (Padjusted <0.0175). In patients with higher SDA values, ipsilateral OF depth values decreased (P <0.05). The LLCPA and OPCP values were higher in Keros I and lower in Keros III (P <0.05). In patients with lower LLCPA and OPCP, endoscopic sinus surgery will be more dangerous for trauma to lateral lamella and intracranial penetration.

Carotid canal and optic canal at sphenoid sinus.

In the present study, we investigated the relationship between sphenoid sinus, carotid canal, and optic canal on paranasal sinus computed tomography (PNSCT). This study was performed retrospectively. PNSCT images of 300 adult subjects (159 male, 141 female). Sphenoid sinus (pneumatisation, dominancy, septation, inter-sinus septa deviation), anterior clinoid process pneumatisation, Onodi cell, carotid and optic canals (width, dehiscence, classification) were measured. In males, type 3 pneumatised sphenoid sinus (in both sides) and in females type 2 pneumatised sphenoid sinus (right side) and type 3 pneumatised sphenoid sinus (left side) were detected more. Anterior clinoid pneumatisation was present 47.2% in males and 39.7% in females. In male group, more septation (i.e. 22.6%, ≥ 3 septa) in sphenoid sinus were detected. Onodi cell was present 26.6 and 19.1% in males and females, respectively. Carotid canal protrudation to the sphenoid sinus wall was present 23.9-32.1% in males and 35.5-36.2% in females. Dehiscence in carotid canal was detected more in females (34%) compared to males (22%). Optic canal protrudation was 33.3 and 30.5% in males and females. Type 4 optic canal was detected more in both gender. Optic canal dehiscence was detected 11.3 and 9.9% in males and females. Carotid and optic canal diameters were higher in males. In pneumatised sphenoid sinuses and in females, type 3 carotid canal (Protrudation to SS wall) (bilaterally) and type 1 optic canal type (No indentation) (ipsilateral side) were detected more. In elderly patients, carotid and optic canal width increased. When carotid canal protrudation was detected, there was no indentation in optic canals In pneumatised SS, carotid canal protrudation was observed with a greater risk in surgery. However, type 1 (non indentation) optic canal was present in highly pneumatised SS with lower risk for the surgery. In women, the risk of carotid canal protruding (about 1/3) is greater than that of males, and carotid canal dehiscence rates are also higher in females. Therefore, physicians should be very careful during the preparatory stages of the sphenoid sinus surgery. Otherwise, it may not be possible to prevent lethal carotid artery bleeds.

Low-Dose Noncontrast Examination of the Paranasal Sinuses Using Volumetric Computed Tomography.

The objective of this study was to evaluate image quality of low dose in noncontrast paranasal sinus computed tomography (CT) using single volumetric 320-row multidetector CT technique. The low-dose protocol including tube voltage of 135 kV and tube current of 5 mAs was chosen based on results of the present phantom study. Forty-six patients were assigned to control group with factory standard settings (120 kVp, 75 mAs), and 46 patients were assigned to study group and underwent noncontrast CT of paranasal sinus with low-dose protocol using single volumetric 320-row multidetector CT device. Objective and subjective image qualities were performed. Effective radiation dose calculated for control group scans was 0.45 (SD, 0.39) mSv. It was 0.038 (SD, 0.004) mSv for study group scans. The effective radiation dose of study group was statistically significant lower than control group (P < 0.001). Noncontrast paranasal sinus CT imaging can be performed at very low radiation exposure maintaining high image quality with 135 kVp and 5 mAs.

Computed Tomography Evaluation of Nasal Bone and Nasal Pyramid in the Turkish Population.

To classify shapes of the nasal bones in the Turkish population and comparatively evaluate the sizes of nasal bone and piriform apertures. Two- and three-dimensional paranasal sinus computed tomography images of 363 patients were evaluated. Upper, intermediate, and inferior thickness of bilateral nasal bones and thickness of medial and lateral osteotomy line were measured. The shapes of the nasal bones were classified. The mean thickness of nasal bone in the study participants was 1.99 ± 0.40 mm, the mean thickness at the level of medial osteotomy line was 1.99 ± 0.40 mm, the mean thickness at the level of lateral osteotomy line was 1.75 ± 0.30 mm, the mean length of nasal bone was 1.75 ± 0.30 mm, maximum width and height of piriform aperture were 23.41 ± 2.68 and 36.76 ± 7.06 mm, respectively. When the patients were classified according to the type of nasal bone, 26.7% had type A, 10.5% had type B, 19.6% had type D, and 15.4% had type E nasal bone. The results of the current study provide information about morphological characteristics of nasal bone and piriform aperture in the Turkish population and would therefore reduce postoperative complications after reconstructive surgery and contribute otolaryngology and anthropology.

Vidian Canal Types and Dehiscence of the Bony Roof of the Canal: An Anatomical Study.

To determine the prevalence of Vidian canal types and dehiscence of the bony roof of the canal. This study included 594 patients (391 males and 203 females; average age, 32.43±11.98 years; range, 18-65 years). Computed tomography (CT) images were analyzed in terms of the prevalence of Vidian canal types and dehiscence of the bony roof of the canal. Vidian canal types 1, 2, and 3 based on the sphenoid sinus body were found on the right side in 33.8%, 29.7%, and 6.5%, and on the left side in 36.4%, 27.4%, and 36.2% of the patients, respectively. Dehiscence of the bony roof of the canal was found on the right side in 22.2% of the patients and on the left side in 26.6%. In terms of Vidian canal types based on the sphenoid sinus floor, types 1, 2, 3, and 4 were found on the right side in 53.5%, 27.4%, 7.6%, and 11.5%, and on the left side in 54.9%, 26.6%, 6.6%, and 11.9% of the patients, respectively. On the right side, Vidian canal type 2 was significantly (p=0.002) more frequent in males than in females. When studying the complex anatomy of the sphenoid sinus, it is essential to consider Vidian canal types. Before endoscopic sinus surgery the Vidian canal and other anatomical structures should be carefully evaluated in all patients during preoperative paranasal sinus CT imaging to avoid complications.

Frontal sinus parameters in computed tomography and sex determination.

The frontal sinus is a sturdy part of the skull that is likely to be retrieved for forensic investigations. We evaluated frontal sinus parameters in paranasal sinus computed tomography (CT) images for sex determination. The study was conducted on 200 normal paranasal sinus CT images of 100 men and 100 women of Persian origin. We categorized the studied population into three age groups of 20-34, 35-49 and ⩾ 50 years. The number of partial septa in the right frontal sinus and the maximum height and width were significantly different between the two sexes. The highest precision for sex determination was for the maximum height of the left frontal sinus (61.3%). In the 20-34 years age-group, height and width of the frontal sinus were significantly different between the two sexes and the height of the left sinus had the highest precision (60.8%). In the 35-49 years age-group, right anterior-posterior diameter had a sex determination precision of 52.3%. No frontal sinus parameter reached a statistically significant level for sex determination in the ⩾ 50 years age-group. The number of septa and scallopings were not useful in sex determination. Frontal sinus parameters did not have a high precision in sex determination among Persian adults.