Medical Imaging can be Confusing, aMRIght?


Over 120 years ago, the x-ray was invented. Since then, medical imaging has advanced to include MRIs, ultrasounds and CT scans.

When you visit a physiotherapist, they will conduct a thorough clinical assessment that will test the relevant integrity of your bones, ligaments, muscles and tendons. The clinical diagnosis you receive is the result of the findings of this thorough assessment, and will be the starting point of your journey to recovery- as imaging is not frequently required.

In some cases, imaging can be used when further investigation is required to form a diagnosis.

However, studies have shown that abnormalities detected via imaging are not always the reason why symptoms are occurring (Balague et al., 2012)

How Do Different Types of Imaging Work?


-One of the most commonly used medical imaging forms are x-rays.

-A plain x-ray uses radiation to create a picture of the inside of the body.

-The x-ray beam is absorbed differently by various structures in the body, such as bones and soft tissues, and this is used to create the image.


-MRI provides better differentiation between fat, water, muscle, and other soft tissue than CT Scans.

-The MRI machine is a large cylindrical device. The body part to be scanned is placed inside the tunnel. The need to keep absolutely still and the restricted space can be poorly tolerated by some people.

-Most MRI machines offer your choice of music or movies and some are even decorated to provide helpful distraction.

CT Scan

-A CT scan uses computers and rotating x-ray machines to create cross-sectional images of the body.

-These images provide more detailed information than normal x-ray images.


-Ultrasound imaging is based on the same principles involved in the sonar used by bats or even fishermen who use fish finders. When a sound wave strikes an object, it bounces back, or echoes.

-By measuring these echo waves, it is possible to determine how far away the object is as well as the object’s size, shape and consistency. This includes whether the object is solid or filled with fluid.

-Ultrasound is reflected by bone and unable to detect fractures.

-Ultrasound waves are also progressively disturbed the deeper they go, so the image integrity is limited for deep structures.

Why Would I Get Imaging Done?

X Ray

-Your Physiotherapist will only order an X-ray if a bone injury is suspected.

-The good news is, that there are validated rules that provide additional confirmation that an x-ray is required. Your Physio will combine the information from your clinical assessment and cross reference it with the results of the validated rule – to prevent you from wasting time and radiation you don’t require

-Sometimes, even when a bone injury is suspected, the Physiotherapist and the client might decide to avoid unnecessary radiation because the chosen treatment would not be changed by the findings on the x-ray.


Your physiotherapist will always conduct a thorough musculoskeletal and neurological assessment AND reach a firm Clinical Diagnosis before and MRI is considered.

Most musculoskeletal injuries and even nerve impingements respond better to physiotherapy than more invasive treatments.

Because of this and the strength of the clinical diagnosis, an MRI is only justified if the condition is unlikely to respond to conservative treatment.

CT Scan

A CT scan may be selected over an X-ray due to the higher detail they provide, as well as being able to more clearly show the soft tissues, blood vessels, and bones in various parts of the body.


-Ultrasound imaging can be used to assess soft tissue structures that are relatively superficial, such as muscles, tendons, ligaments, nerves and joints throughout the body. If your Physiotherapist makes a clinical diagnosis of a grade 2 or 3 tear, an ultrasound may be ordered to confirm.

-Your Physiotherapist has the skills to determine the severity of an injury, with or without the use of ultrasound.

-At Target Physio we also use ultrasound during a treatment. It allows us to see the working of muscles such as the pelvic floor in real time.
Being able to watch the muscle moving helps the Physiotherapist be very precise with treatment and also has tremendous value for the client who is able to watch.

How Much Radiation is Involved?

All medical imaging is performed by highly trained professionals, and is not performed unless necessary. The levels of radiation are not dangerous to your long-term health, or cause any side effects.

X Ray

-To put it into perspective, each year we are naturally exposed to approximately 3 millisieverts of ionising radiation.

-An x-ray of your spine will expose you to approximately 1.5 millisieverts of radiation, so approximately 6 months of your yearly dose.

-Whereas an image of your extremity, such as your hand or foot, will expose you to 0.001 millisieverts of radiation, so approximately 3 hours of your yearly dose.


-Unlike CT scans and X-Rays, there is no radiation with MRIs.

-MRIs do produce a strong static magnetic field which can be interfered with by any metal on or in your body.

CT Scan

-Like X-rays, CT scans do expose you to varying levels of radiation.

-A CT scan of your thoracic spine will expose you to approximately 6 millisieverts of radiation, so approximately 2.5 times your yearly dose.

-Whereas an image of your pelvis would expose you to 10 millisieverts of radiation, so approximately 4.5 times your yearly dose.


-Unlike CT scans and X-Rays, there is no radiation with ultrasounds. There are also no known risks associated with this form of imaging.

Who can refer and will I be out of pocket?

X Ray

-You will need a referral from a health professional, such as a Physiotherapist or a GP to receive an x-ray. With this referral, the cost will usually be bulk-billed through Medicare, regardless of who refers you.


-Because an MRI is an expensive investigation, it is often reserved to bring clarity prior to surgery, injection therapy or immobilisation. There are specific criteria where a GP or a Specialist may refer for bulk billed MRIs.

-Bulk billed MRIs have very restricted criteria. Self-funded MRIs are more common. There are many scenarios when the cost is no different if the referral comes from either a Physiotherapist, a GP or a Specialist.

CT Scan

-In terms of being referred for a CT scan, both GPs and specialists can provide referrals that are rebatable by Medicare.


-In terms of being referred for an ultrasound, most health professionals such as referrals by Physiotherapists and GPs are rebatable by Medicare.

View the first video in our Imaging series below, or check out the full video playlist here. 

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