The emergence of medical imaging tools has revolutionised how we can study the body and identify problems with our internal structures. For rare diseases, advancement in technology has helped form our understanding of how to diagnose and treat them. In this article, we will explore how medical imaging has helped manage the symptoms of the rare disorder, frontonasal dysplasia. 

Overview of frontonasal dysplasia

What is frontonasal dysplasia? 

Frontonasal dysplasia (FND) is a rare disorder in which the head and face become malformed due to problems with the embryonic development of the facial midline.¹ These malformations become apparent at birth and, therefore, FND is often classified as a congenital disorder.

These facial defects can take many forms, including a cleft palate, increased distance between the eyes (hypertelorism) and an underdeveloped, misshapen nose. Other features of this disorder include hair loss on the head and eyebrows or a V-shaped hairline known as ‘widow’s peak’. This disorder manifests differently between affected individuals, so some people may have mild features, whilst others may have very severe features. Whilst the severity of the disorder has been linked to genetics, many cases of frontonasal dysplasia are random and difficult to predict.

For those with severe frontonasal dysplasia, these facial malformations can be life-threatening. Those with abnormal nose shapes or nasal clefts can have narrowed nostrils, which can lead to breathing difficulties. Regardless of the severity of the disorder, having facial defects can negatively affect a person's quality of life. One way to overcome these problems is through reconstructive facial surgery.

Treatments for frontonasal dysplasia 

There is currently no cure for frontonasal dysplasia. Through many decades of scientific research, there have been emerging treatments, including gene therapy and tissue engineering, to try and prevent and even reverse these facial defects. However, it will take many more years and scientific experiments before these treatments can be tested on humans.

Currently, the only treatment for frontonasal dysplasia is surgery to recorrect these facial abnormalities. Whilst this is not a cure in itself, these surgeries can greatly improve the quality of life for the affected individuals. Examples of facial surgeries include:

• Rhinoplasty - Rhinoplasty is a type of plastic surgery. The term rhinoplasty refers to a surgical procedure aimed at correcting the shape of the nose. You may have come across this term in the media, with many celebrities having a ‘’nose job’’ to alter the shape of their nose for aesthetic purposes. But rhinoplasties can be very useful in other contexts, too. For example, this surgery can be done to treat injuries (e.g. from rugby players), help with breathing problems (e.g obstructive sleep apnoea) and correct facial abnormalities like those seen in frontonasal dysplasia. Despite being a common plastic surgery, rhinoplasty is very complex to do due to the small size and complex shape of the nose. As such, rhinoplasties require great skill and care from surgeons to ensure the operation is carried out without complications
• Facial bipartition - facial bipartition is a surgical procedure aimed at repositioning the face by bringing the facial bones closer together. In the context of frontonasal dysplasia, this surgery can be used to correct the widely spaced eye positions and abnormal head shape that some individuals with frontonasal dysplasia may have. This surgery requires great communication between plastic surgeons and neurosurgeons. Therefore, appropriate surgical planning is crucial to prevent any complications from occurring

The emergence of medical imaging tools

Types of medical imaging tools 

Imaging technologies have been very valuable tools to help clinicians accurately diagnose diseases and identify different anatomical structures and abnormalities within the body. If you have ever broken a bone or had a sore toothache, you may have seen an X-ray of your bones before. Whilst X-ray images can help with assessing the severity of an injury and plan out the next steps for treatments, these are only static 2D images and so have limited use for more complicated cases.

The emergence of 3D imaging tools in recent decades has vastly improved the accuracy of disease diagnosis as they allow a more detailed view of the anatomical structures within the body. 3D imaging tools have a range of applications in medicine, ranging from dentistry, pregnancy and cancer screening. Some examples of imaging tools include: 

CT scans

A computerised tomography (CT) scan uses X-rays and special computer technology to create cross-sectional images of the body. CT scans create much more detailed images than singular X-ray images, so they are far more advantageous to use in a medical setting. CT scans are able to provide images of both soft and hard tissues of the body, and are useful in visualising the brain and facial features. Despite the advantage over X-rays, CT scans are very expensive and can deliver a high dose of radiation to the individual who needs them.

Cone beam CT scans (CBCT)

A CBCT scan can overcome some of the issues with conventional CT scans by delivering lower doses of radiation to the patient. CBCT scans can be used to create images of the head and neck and have been particularly useful in the dentistry field to visualise the jaw. The use of CBCT scans in the management of patients with cleft lips was found to deliver almost 4 times lower dose than a normal CT scan,² highlighting its suitability as a tool to manage the treatment of congenital facial malformations, including those seen in frontonasal dysplasia. 

MRI scans

A magnetic resonance imaging (MRI) scan uses a strong magnetic field and radio waves to create high-resolution images of soft tissues. MRI has allowed scientists to visualise the grey and white matter of the brain and has become an important diagnostic tool for brain injuries. 

Ultrasound

Ultrasound works by using sound waves to create images of our internal organs. When the sound waves reach an internal organ, the waves can bounce and echo which is then transformed into an electrical current. This can be used to generate an image or a sonogram, which can be interpreted in real time. Whilst ultrasound can create 2D images, like those used during pregnancy check-ups, 3D ultrasound images can be created too. Ultrasound images are far more practical than CT or MRI imaging techniques as it is non-invasive, cheap and free from radiation. 

These imaging tools have become very important to help with the diagnosis of and plan out surgery for those with frontonasal dysplasia.

Application of medical imagery: diagnosis

Pregnancy ultrasound is the standard procedure used to check the health of the baby, identify the gender and check for any abnormalities. In the case of frontonasal dysplasia, ultrasound can be used as a tool to identify any facial abnormalities.

In one case study, 3D ultrasound was used during a pregnancy check-up of a young woman at 20 weeks.³ During the checkup, facial abnormalities were noted, including a cleft lip, widely spaced eyes and underdeveloped nerves in the brain, suggesting the foetus had severe frontonasal dysplasia. After talks with the clinicians, the couple chose to terminate the pregnancy and the diagnosis of frontonasal dysplasia was later confirmed. Of note, genetic tests run on the parents and the amniotic fluid showed no signs of mutations, which highlighted the inherent random nature of this disorder. Ultimately, this study demonstrated how 3D ultrasound can be a useful tool for early diagnosis of frontonasal dysplasia. 

Application of medical imagery: surgical planning

Facial reconstructive surgeries are complex operations and come with high risk. For the majority of cases, young children will not be operated on as it is expected that their faces will continue to develop and change. However, exceptions must be made, especially for those who are already suffering the consequences of severe facial abnormalities.

One case study followed the surgical planning for a young boy with frontonasal dysplasia who required facial bipartition surgery to correct the space between his eyes.⁴ CT scans were used to plan out his surgery and simulate the volume of bone that needed to be removed to ensure alignment of the face. These 3D models of his face were used to calculate customised cutting guides before the operation. This meant that during the operation, the overall time in surgery and exposure to anaesthetic was decreased whilst simplifying the procedure for the surgeons involved. Therefore, this pre-operative ‘virtual’ surgical planning helped to reduce the risk of surgical complications.

Summary 

3D imaging tools have become very important in the diagnosis and treatment of frontonasal dysplasia. They have helped to improve the quality of patients' lives and deepened our understanding of the disorder. Having 3D imaging tools allows for personalised patient management plans to be thought of and can help parents make informed decisions about the future of their children.