Ultrasound vs X-Ray in Ajax: Which Test and Why

X-ray and ultrasound are two of the most commonly ordered imaging tests in Canada, and they often appear side by side on the same requisition form. Patients reasonably wonder why their provider chose one rather than the other, whether one is “better,” and what the practical differences are when it comes to booking, preparing and the exam itself.

The short version is that the two tests use completely different physics, see different parts of the body well, and answer different clinical questions. Neither is a more advanced version of the other. Your health-care provider chooses based on what they are trying to find out. This guide explains the reasoning so that the choice makes more sense when you see it on your requisition, and so you know what to expect when you come in to a clinic in Ajax for either test.

Two very different ways of making a picture

How X-ray works

An X-ray machine sends a brief, controlled beam of X-ray energy through the body toward a detector. Dense tissues, such as bone, absorb more of the beam and appear bright on the image. Soft tissues let more of it pass through and appear in shades of grey, while air-filled spaces such as the lungs appear dark.

The result is a still, two-dimensional picture, something like a shadow map of the body. Because it relies on differences in density, X-ray is excellent at showing bones and the contrast between air and tissue in the chest.

How ultrasound works

Ultrasound uses no X-rays at all. A handheld device called a transducer sends high-frequency sound waves into the body, well above the range humans can hear. Those waves bounce back as they meet boundaries between different tissues, and a computer turns the returning echoes into a live, moving image.

A small amount of gel is placed on the skin so the sound travels well. The sonographer moves the transducer over the area and records images and short clips as they go. Some ultrasound techniques, called Doppler, can also show the direction and speed of blood flow in vessels.

What each test sees best

Because they work so differently, each test has a “home territory.”

Where X-ray usually leads

• Possible fractures or dislocations
• Arthritis changes in the bones of a joint
• Spine alignment and some back concerns
• Chest concerns, such as a persistent cough
• Some immigration and employment medical requirements, such as an immigration chest X-ray

Where ultrasound usually leads

• Abdominal organs such as the liver, gallbladder, kidneys and spleen
• Pelvic organs
• Pregnancy, from early dating scans through later growth checks
• The thyroid and other structures in the neck
• Lumps or swellings just under the skin
• Tendons, ligaments and muscles, using musculoskeletal ultrasound
• Arteries and veins, using vascular ultrasound, which looks at blood flow and can help assess for clots or narrowing

The radiation question

Many people’s first question is about radiation, so it is worth addressing directly.

Ultrasound does not use ionizing radiation. That is one reason it is the standard imaging test used routinely in pregnancy, and why it is often a first choice for looking at soft-tissue concerns in children.

X-ray does use ionizing radiation, but a standard diagnostic X-ray uses a low dose, and imaging teams work to keep exposure as low as reasonably achievable. Technologists narrow the beam to the area being examined and choose settings suited to the patient and the body part.

It is important not to treat “no radiation” as automatically “better.” If your provider needs to see a bone, ultrasound simply cannot give the same information. Choosing a test that cannot answer the question would only delay the answer. If you have concerns, including the possibility of pregnancy, the best step is to talk them over with your provider and to tell the technologist or sonographer before your exam.

Preparing for each test

This is where the two tests feel most different from a patient’s point of view.

Preparing for an X-ray

For most plain X-rays there is no special preparation. You may be asked to:

• Remove jewellery, a belt, glasses or other metal near the area being examined
• Change into a gown for some exams
• Hold still, and for chest images, hold your breath for a moment

Preparing for an ultrasound

Ultrasound preparation depends on the area being examined, and the instructions matter because they affect image quality:

• Some abdominal scans require fasting beforehand, because food and the gas it produces can make some organs harder to see and the gallbladder changes after a meal.
• Pelvic scans may require a full bladder. A full bladder acts as a window that helps sound waves reach the pelvic organs.
• Other scans, such as many musculoskeletal or neck ultrasounds, need little or no preparation.

At Rossland Diagnostic Clinic, you will receive instructions for your specific ultrasound before your appointment. If anything is unclear, call the clinic and ask. Always bring your health card.

What the visit feels like

An X-ray visit

At our Ajax clinic, X-ray is offered as a walk-in service: Monday to Friday 9:00am to 5:00pm and Saturday 8:00am to 3:30pm. The department may close once daily capacity is reached, so calling ahead for live availability is wise. Once you are in the room, most of the time is spent positioning you carefully. Each exposure lasts only a moment, and several views are often taken.

An ultrasound visit

Ultrasound is done by appointment, which gives time for any preparation and for the sonographer to complete the full set of images your provider requested. You lie on an exam table, gel is applied, and the sonographer moves the transducer over the area, sometimes pressing gently to get a clear view. You may be asked to turn, hold your breath or change position. The gel can feel cool but wipes off easily afterward.

An ultrasound usually takes longer than a plain X-ray, because the images are captured live and the sonographer works through a series of views. Many patients find it a quiet, comfortable experience.

When you might have both

It is common to have both tests for the same concern, and that does not mean something is wrong. Each test fills in part of the picture.

Some examples of how providers may use them together:

1. A painful shoulder. An X-ray can show the bones and joint spaces, while an ultrasound can look at the tendons and fluid around the joint.
2. A sore heel or ankle after an injury. An X-ray checks for a fracture; if it is clear and pain continues, an ultrasound may be used to look at the tendons and ligaments.
3. A lump or swelling. Ultrasound often comes first to see whether it is fluid-filled or solid, with X-ray sometimes added to look at nearby bone.
4. Breast imaging. Mammography is a specialized low-dose X-ray of the breast, and breast ultrasound is sometimes used alongside it to look more closely at a specific area.

Your provider decides the order and combination of tests. If you are unsure why both were ordered, it is fine to ask them what each one is meant to show.

Questions to ask your provider

A few questions can make the choice feel clearer:

• What are you hoping each test will show?
• Is there any preparation I need to do, and do I need to book ahead?
• If I might be pregnant, does that change which test is used?
• How and when will I hear about the results?

Results from both X-ray and ultrasound are sent to the health-care provider who ordered the test, who will review them with you and discuss next steps.

A few common mix-ups

Patients in Ajax sometimes arrive with ideas about these tests that are worth gently correcting:

• “Ultrasound is only for pregnancy.” Pregnancy scans are the best-known use, but ultrasound is used every day for organs, the thyroid, soft-tissue lumps, tendons and blood vessels in people of all ages.
• “An X-ray shows everything inside.” Plain X-ray is very good at bone and the chest, but soft tissues such as tendons, ligaments and many organs show up only faintly, if at all.
• “If my X-ray was normal, nothing is wrong.” A normal X-ray means nothing concerning was seen on that test. If symptoms continue, your provider may still want a different test to look at structures X-ray does not show well.
• “A longer test means something was found.” Ultrasound naturally takes longer because images are captured live and the sonographer works through a set series of views. The length of the exam is not a sign of a result either way.
• “I can choose the test myself.” Your health-care provider orders the test that fits the clinical question. If you would prefer a different option, raise it with them so they can explain their reasoning.

The bottom line

X-ray and ultrasound are partners rather than rivals. X-ray is quick and excellent for bones and the chest. Ultrasound is radiation-free and excellent for soft tissues, organs, blood flow and pregnancy. Your provider picks the tool that fits the question, and sometimes the best answer comes from using both.

Patients across Ajax, Pickering and Whitby can access both tests at Rossland Diagnostic Clinic, Unit 102, 300 Rossland Road East, with free parking and ground-floor access. To book an ultrasound, request an appointment online or call 905-426-3111. For a walk-in X-ray, call the same number to check live availability before you come.