CT Anatomy of sinuses | enteducationswansea

Interpreting CTs of the Nose and Sinuses

Studying CT scans can help with your understanding of anatomy and is a vital prelude to understanding pathological findings revealed by the investigation. On this page are presented normal CT anatomy in two planes and a selection of pathological scans with commentary.

There are some things that you need to know before you start.

Key facts.

1. 40% of people have abnormalities in the sinuses on CT scanning. This means that four out of ten people without any nasal symptoms or problems with their sinuses have an abnormality when scanned.

2. Rhinosinusitis is diagnosed clinically. This means that we use our knowledge of the disease and our physical examination skills to make the diagnosis. We do not use a CT scan.

3. A CT scan is used when we are planning surgery as it gives a good view of the anatomy of the sinuses and shows the surgeon where important structures such as the lamina papyracea and cribriform plate are.

4. Plain X-rays of the sinuses are no help in making a diagnosis in the majority of patients.

Introduction

A good knowledge of the anatomy of the face, nose and sinuses is essential before trying to understand the CT anatomy. CT scans can be formatted in any plane: axial, coronal and parasagittal. In practice we use the coronal scans most but when we operate on the sinuses all views are useful. Review the tutorial on the physiology and anatomy of the nose before proceeding.

Normal Radiological Anatomy

The following sequence of slides shows normal anatomy in the axial plane and then the coronal plane. Once you understand the radiological appearances of the sinuses we will look at pathology.

Axial Anatomy

Axial CT scan through the forehead

Axial CT scan through the root of the nose

Axial CT scan through the orbit

Axial CT scan through the cheek

Axial CT scan through the palate

Coronal Anatomy

Coronal CT through the nose

Coronal CT through frontal Sinuses

Coronal CT through the Cribriform Plate

Coronal CT through Posterior Nose

Coronal CT through the Orbital Apex

Coronal CT through Sphenoid Sinus

Cases with Pathology

Below are examples of CT scans with pathology. It is not usually possible to state what the exact pathology is by looking at a CT scan and clinical examination with histological study give a better understanding. Don’t be tempted to make a diagnosis on the scan alone, always correlate the scan with clinical findings.

Case courtesy of A.Prof Frank Gaillard

The scan shows extensive opacity of the left maxillary sinus and left ethmoids sinus.

The right sided sinuses are not affected. The contents of the left orbit are normal.

The patient was suffering a left sided acute sinusitis.

Case courtesy of Dr Bruno Di Muzio

Here we see opacification in both maxillary and both ethmoids sinuses. The patient had bilateral chronic rhinosinusitis.

Case courtesy of Dr Fakhry Mahmoud Ebouda

The scan shows opacification of the right maxillary sinus and a polyp filling the right nasal cavity.

This was an antro-choanal polyp and the polyp extended backwards into the back of the nose. These polyps can sometimes be seen through the open mouth.

There is a small amount of mucosal swelling in the left maxilla.

Case courtesy of Dr Paresh K Desai

The left side of this patient shows opacification throughout the maxilla and ethmoids sinuses. The density of the opacity is different in the maxilla from that in the ethmoids.

This patient had an inverting papilloma in the nose that had obstructed the maxillary drainage and caused a secondary maxillary sinusitis.

You can see that the papilloma is expanding and pushing the septum to the right.

Inverting papillomas have a slight tendency to become malignant.

Case courtesy of Dr Abdel-Rahman Abdel-Halim

Here we see opacification of the left sphenoid sinus and an adjacent posterior ethmoids cell.

The patient had a sphenoid sinusitis and headache. This case is unusual and we usually see sphenoid disease in cases where all of the sinuses are involved.

Case courtesy of Dr Fakhry Mahmoud Ebouda

This scan shows a number of interesting features.

The right maxilla and ethmoids are full of a soft tissue which has variable opacification. The lamina papyracea is broken down in places and the septum also appear to be eroded.

This is an invasive fungal sinusitis – a rapidly fatal disease if left untreated.

It is commoner in immunocompromised patients.

Management is with aggressive medical and surgical treatment.