POSTER SECTIONS Coverpage Learning objectives Background Findings and procedure details Conclusion Personal information and conflict of interest References

ECR 2023 / C-24563

How to read a temporal bone CT in 5 simple steps… and some tricks

Congress:

ECR 2023

Poster Number:

C-24563

Type:

Educational Exhibit

Keywords:

Anatomy, Ear / Nose / Throat, Head and neck, Cone beam CT, CT, CT-High Resolution, Education, Normal variants, Technical aspects, Education and training

Authors:

N. Villarreal del Bosque, M. Sada

DOI:

10.26044/ecr2023/C-24563

DOI-Link:

https://dx.doi.org/10.26044/ecr2023/C-24563

Learning objectives

1. Review the radiological anatomy of the temporal bone and show some tricks and pearls to identify the anatomical structures 2. Show a proper protocol for a temporal bone CT 3. Describe how to read a CT scan of the temporal bone in 5 steps

Background

CT of the temporal bone is the imaging study of choice for most ear pathologies, the interpretation carries some challenges due to the complex anatomy and the small size of the structures. These educational exhibits explain the essential points for an adequate assessment of the temporal bone CT.

Findings and procedure details

Acquisition and reconstruction of CT protocol: A large FOV acquisition of the skull base with soft tissue window and bone algorithm 1.25 mm (Fig 1), the scan must be performed avoiding direct irradiation of the lens of the eye [Fig 1] A small FOV for each ear with bone algorithm 0.625 mm, with the following planes: ”True axial”: parallel to the lateral semicircular canal (Fig 2)[Fig 2] Coronal plane: passes perpendicular to the hard palate Sagittal plane: passes perpendicular to the coronal (Fig 3)[Fig 3]...

Conclusion

The evaluation of the ear by CT offers an excellent representation of the anatomy. Understanding the anatomy of the temporal bone is essential to recognize pathologies. An adequate acquisition and reconstruction of the images are necessary for a correct interpretation. Using some signs, structures can be adequately recognized.

Personal information and conflict of interest

N. Villarreal del Bosque: Nothing to disclose M. Sada: Nothing to disclose

References

Som, P. M., & Curtin, H. D. (2011). Head and neck imaging. Mosby Elsevier. Kim YW, Mansfield LT. Fool me twice: delayed diagnoses in radiology with emphasis on perpetuated errors. AJR Am J Roentgenol. 2014;202 (3): 465-70 Amy F. Juliano, Daniel T. Ginat, Gul Moonis. Imaging Review of the Temporal Bone: Part I. Anatomy and Inflammatory and Neoplastic Processes. (2013) Radiology. Isaacson B. Anatomy and Surgical Approach of the Ear and Temporal Bone. (2018) Head and neck pathology. 12 (3): 321-327. Mansour S, Magnan J,...

Fig 1: CT axial plane with bone algorithm (A) and soft tissue window (B). Lateral...

Fig 2: True axial plane of the temporal bone (A) passes parallel to the lateral...

Fig 3: Examples of a CT in coronal plane (A) and sagittal plane (B) for each ear.

Fig 4: Axial CT scan (A) showing the Poschl (B) and Stenvers (C) planes, passing...

Fig 5: Axial CT scan with soft tissue window showing the anatomy of the nasopharynx in...

Fig 6: 3D surface volume rendering of the pinna showing its anatomical references.

Fig 7: CT scan showing the external auditory canal (EAC) in a sagittal plane (A), an...

Fig 8: CT scan showing the mastoid cells in a axial plane (A). The antrum (B) connect...

Fig 9: Poschl plane (A) and axial plane (B) showing the tympanic membrane formed by...

Fig 10: Coronal section of a computed tomography of the ear showing the tympanic...

Fig 11: CT in axial plane in successive slices (A-E) showing the most important parts...

Fig 12: CT in axial plane (A) and with magnification (B) showing the Prussak´s space,...

Fig 13: CT in axial plane in successive slices (A-F) showing the most important parts...

Fig 14: CT in axial plane in successive slices (A-C) showing the most important parts...

Fig 15: CT in axial plane in successive slices (A-B) showing the most important parts...

Fig 16: CT in sagittal plane (A) and coronal plane (B) showing the roof or tegmental...

Fig 17: The head of the malleus and the body and short process of the incus lie above...

Fig 18: Hex key (A), CT in axial plane showing the incudostapedial joint as a inverted...

Fig 19: CT in axial plane showing the oval and round window (A and B). CT in Poschl...

Fig 20: CT in axial plane in successive slices (A-D) showing the parts of the facial...

Fig 21: CT in axial plane (A-C) showing the cochlea and vestibule. CT in coronal plane...

Fig 22: CT axial plane al the level of the fissula antefenestram (A). The fissula...

Fig 23: CT in axial plane (A-B) showing the IAC, porus acusticus and Bill´s bar. CT in...

Fig 24: What to look for each plane of section (sagittal, coronal, Stenvers and Poschl)

Fig 25: CT on sagittal plane in successive slices (A-C) showing the anatomical...

Fig 26: CT on sagittal plane in successive slices (A-D) showing the anatomical...

Fig 27: CT on coronal plane in successive slices (A-C) showing the anatomical...

Fig 28: CT on coronal plane in successive slices (A-C) showing the anatomical...

Fig 29: CT on Stenvers plane in successive slices (A-D) showing the anatomical...

Fig 30: CT on Poschl plane in successive slices (A-E) showing the anatomical structures...