The pneumatization of the sphenoid sinus, its variations and relations with surrounding neurovascular anatomic structures: A computerized tomography study

An artificial intelligence algorithm for the classification of sphenoid sinus pneumatisation on sinus computed tomography scans

BACKGROUND

Classifying sphenoid pneumatisation is an important but often overlooked task in reporting sinus CT scans. Artificial intelligence (AI) and one of its key methods, convolutional neural networks (CNNs), can create algorithms that can learn from data without being programmed with explicit rules and have shown utility in radiological image classification.

OBJECTIVE

To determine if a trained CNN can accurately classify sphenoid sinus pneumatisation on CT sinus imaging.

METHODS

Sagittal slices through the natural ostium of the sphenoid sinus were extracted from retrospectively collected bone-window CT scans of the paranasal sinuses for consecutive patients over 6 years. Two blinded Otolaryngology residents reviewed each image and classified the sphenoid sinus pneumatisation as either conchal, presellar or sellar. An AI algorithm was developed using the Microsoft Azure Custom Vision deep learning platform to classify the pattern of pneumatisation.

RESULTS

Seven hundred eighty images from 400 patients were used to train the algorithm, which was then tested on a further 118 images from 62 patients. The algorithm achieved an accuracy of 93.2% (95% confidence interval [CI] 87.1-97.0), 87.3% (95% CI 79.9-92.7) and 85.6% (95% CI 78.0-91.4) in correctly identifying conchal, presellar and sellar sphenoid pneumatisation, respectively. The overall weighted accuracy of the CNN was 85.9%.

CONCLUSION

The CNN described demonstrated a moderately accurate classification of sphenoid pneumatisation subtypes on CT scans. The use of CNN-based assistive tools may enable surgeons to achieve safer operative planning through routine automated reporting allowing greater resources to be directed towards the identification of pathology.

Sphenoid Sinus Pneumatization Types and Correlation with Adjacent Neurovascular Structures Using Cone-Beam Computed Tomography

Aims: This study aimed to assess the sphenoid sinus pneumatization types and their correlation with adjacent neurovascular structures using cone-beam computed tomography (CBCT). Materials and methods: This cross-sectional study was conducted on 97 CBCT scans of patients over 18 years of age that were retrieved from the archives of the Oral & Maxillofacial Radiology Department of School of Dentistry. Type of sphenoid sinus pneumatization based on its relationship with sella turcica (conchal, presellar, sellar, and postsellar), the correlation of internal carotid artery (ICA) and optic nerve (ON) with the sinus cavity in the axial and coronal planes (smooth or prolonged type), and presence of Onodi cells and their correlation with the sphenoid sinus (lateral, superior, and superolateral) were all evaluated on CBCT sections. Data were analyzed by the Chi-square and Fisher's exact tests (alpha = 0.05). Results: Postsellar type was the most common sphenoid sinus pneumatization type (82.5%). The Smooth type was the most common form of correlation of ON and ICA with the sphenoid sinus. Onodi cells were noted in 28.9% of the cases; among which, the lateral type had the highest prevalence. Conclusion: Considering the high prevalence of sphenoid sinus pneumatization, Onodi cells, and ON and ICA protrusion in our study population, CBCT should be requested prior to trans-sphenoidal surgical procedures to prevent perioperative and postoperative complications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03796-0.

Pneumatization of the Greater Wing of Sphenoid Utilization for Lateral Wall Decompression

The goal of orbital decompression for thyroid orbitopathy is to expand the orbital space for the contents with various techniques described. Deep lateral wall decompression is a procedure that expands the orbit by removing bone from the greater wing of sphenoid however its effectiveness is dependent on the volume of bone removed. Pneumatization of the greater wing of sphenoid is defined as an extension of the sinus beyond the VR line (a straight line crossing the medial edges of the vidian canal and the foramen rotundum) which is a demarcation between the sphenoid body and the lateral parts of the sphenoid bone, including the greater wings and pterygoid process. We present a case of complete pneumatization of the greater wing of sphenoid affording a greater volume of bony decompression in a patient with significant proptosis and globe subluxation as a result of thyroid eye disease.