One of the most important elements of modern medicine is the diagnostic process especially in medical imaging. Diagnostic errors may result in delayed treatments or worse, incorrect and potentially toxic medications. Over-diagnosis is also a concern, which often end up in over-treatment and undue stress to the patient. Getting the correct diagnosis is key to providing not just the correct medicines and/or medical procedures, but also the quick restoration of the patient’s quality of life.
There are various technologies that help with the diagnostic process. These include various medical imaging equipment, from microscopes, x-ray machines, to ultrasound and MRI machines and CT scanners.
Upon the collection of specimen like blood, spinal fluid, or muscle tissue, doctors prepare slides of these samples after which they are stained or dyed. Different cells react to different stains or dyes, and the resulting colors will help guide the doctors in determining the patient’s medical condition.
Once the slide is placed under the lens of the microscope, it’s only a matter of zooming into the cells to find out if anything is wrong. Most microscopes used in diagnostic processes are already automated and digital, and are up to 400 times more powerful than human vision, so even the smallest changes to a cell’s structure can be detected. Automated digital microscopes are also equipped with motorized microscope stages, which allows the operator to precisely position the sample for sequential or scanning imaging. Meanwhile, the objectives of these modern microscopes are fitted with linear motors so that they can be moved relative to the sample and maintain the required focus for clearer images.
X-Ray Machines and CT Scanners
One of the most common diagnostic imaging tools is the X-ray machine. Also called radiographs, X-ray machines send a blast of electromagnetic waves through the body part being scanned. Denser matter like bones and tumors absorb this radiation, so they appear whiter on the X-ray film or the resulting digital image. Soft tissues like muscle and ligaments allow the radiation to pass through, so they look more translucent. If there are solid white parts in these sections that are supposed to be clear, it simply means that something is out of place and your doctor may issue more tests.
CT scanners, on the other hand, use a combination of X-rays and computer imaging to take detailed, cross-section pictures inside the body. The usual targets of CT scans are the organs, such as the heart, intestines, kidneys, liver, lungs, and pancreas, although it can also be used to study the blood vessels and bones. When done correctly, CT scans can reveal tumors and cancer cells, organ enlargement, infections, and blockages like kidney stones and embolisms, among others. CT scanners can also help doctors during tissue biopsy; the resulting image can guide the proper placement of the needle to prevent puncturing neighboring tissues.
Like CT scanners, MRI or magnetic resonance imaging machines also provide cross-sectional images. However, instead of using X-rays, MRIs use magnetic fields to take high-resolution photos of tissues. This is why you should advice your doctor if you have implants, pacemakers, or other metal objects as these can lead to false positives or even damage these devices.
In medical imaging technology, MRI machines work by creating a magnetic field around your body, and then pulsing radio waves to the part of your body that needs to be studied. Your tissues then vibrate, and a computer records and translates these vibrations into a two-dimensional image. Usually, MRIs are recommended to diagnose problems in the brain, chest, abdomen, and pelvis.
When people think of ultrasounds in medical imaging technology, they usually imagine a pregnant woman checking up on her unborn child’s health, or perhaps checking if she should buy pink or blue baby clothes. However, apart from fetal imaging, ultrasounds can also be used to diagnose conditions that affect the organs and soft tissues like the eyes, hear, kidneys, bladder, ovaries or testicles, and gallbladder. Because it uses high-frequency sounds that bounce against tissues in order to produce an image, an ultrasound isn’t used to take images of body parts that hold air or gas, like the intestines. However, ultrasound imaging may be used to guide doctors in needle biopsies as well as in treating soft-tissue injuries.
The first step in getting better is knowing exactly what disease you need to treat. Thanks to these medical imaging solutions, doctors can come up with correct diagnoses to help patients receive proper and timely medical care.
Medical Imaging and Diagnostics
Medical imaging and diagnostics are vital in a wide range of medical settings. They help doctors find tumors and blood clots; locate broken bones; and guide surgeons during operations.
When you were a kid, did you ever daydream about having superhero powers like x-ray vision? Well, medical imaging is a lot closer to that fantasy than you might think.
Computed tomography (CT) scans
A computed tomography (CT) scan or CAT scan provides doctors with detailed pictures of internal organs, blood vessels and soft tissues. It can also show bone damage or a tumor. It works similarly to standard X-rays. A narrow beam of radiation passes through the body part being studied and a plate captures the variations in the amount of radiation that hits it. Different body parts absorb different amounts of radiation, so the resulting images show up in shades of gray. Bones appear white, while heart and other organs appear darker. A computer then puts the information together to create two-dimensional cross-sectional images of a selected area. The images can then be rearranged to give a three-dimensional view. A CT scan can be used to identify a wide range of diseases and injuries, including brain tumors, fractured bones, liver or kidney problems and other infections.
A CT scan can be performed at a hospital or radiology clinic. You will be asked to lie down on an exam table, and your doctor may use straps or pillows to help you stay still. You may be given a contrast dye to help your organs and blood vessels stand out in the images. It is often swallowed as a liquid, but it can also be injected into a vein (IV). Depending on the type of scan, you might need to wear a gown or remove some of your jewelry or other items that might interfere with the results.
After the scan, you will be asked to wait while the results are processed. The radiologist, who is a physician specially trained to oversee and interpret radiology exams, will review the images and send an official report to your doctor. Your doctor will explain the findings and discuss treatment options. Occasionally, your doctor will order a follow-up exam to see how well your treatment is working or if there has been any change in an existing problem. A follow-up exam may involve more views of the area or a different imaging technique.
X-rays are an important diagnostic tool and are commonly used to detect fractures, dislocations and some illnesses. They are also useful in evaluating the effectiveness of medical treatments.
Unlike other forms of electromagnetic radiation, X-rays can pass through the human body without being absorbed or reflected. However, a portion of the energy is absorbed by the tissue, which causes it to produce an image on the detector. This is the basic principle behind X-ray imaging.
The images produced by X-rays are called radiographs and can be seen on film or displayed digitally. X-rays can be used to view bones, muscles, blood vessels and some internal organs. The bones appear white against a black background on an X-ray, while soft tissues (such as lung and abdominal walls) appear shades of gray. Bones are more dense than other tissues, so they show up more clearly on X-rays.
In some cases, doctors may use a contrast agent with an X-ray to make certain tissues, such as the kidneys, appear more clearly. During this procedure, the doctor will inject you with a contrast medium, such as barium or iodine, either orally or intravenously. You may feel some temporary side effects, such as pain or bloating from the injection. Your appointment letter will mention whether you are likely to have a contrast agent.
You can expect an X-ray examination to be simple and quick. The technician will ask you to stand or sit in different positions as they take pictures from various angles. In some cases, they may use pillows or sandbags to prop up your body part to get a better view of it. You may be asked to hold your breath or keep still during the test. A radiologist will then assess the results and send the report to your doctor, who will explain them to you.
An X-ray exposes you to a small amount of radiation, but this is unlikely to cause any harm, especially for children. If you are pregnant, talk to your doctor before having an X-ray as it can expose the foetus to radiation. There is a small increased risk of cancer in later life for people who receive too many X-rays, so it is important to limit your exposure as much as possible.
Fluoroscopy (floo-ROS-kuh-pee) is a special imaging test that makes x-ray movies of your body as it moves. These x-rays are shown on a screen, like a TV monitor, in real time. They can help your doctor diagnose problems and guide other procedures. For example, your doctor might use fluoroscopy to guide a catheter into a blood vessel or duct. The x-ray movie lets your doctor see where the catheter is going and helps them avoid hitting a blood vessel or nerve. Fluoroscopy is also used to guide the placement of other objects, such as stents, into narrow or blocked blood vessels.
The type of preparation you need for fluoroscopy depends on the kind of procedure being done. You may be asked to wear comfortable clothing without zippers or buttons and to remove metal objects such as jewelry. You will be asked to lie on a table and to follow your doctor’s instructions for how to position yourself for the exam. Some patients are given a contrast dye during the fluoroscopy procedure. There is a small risk of having an allergic reaction to the contrast dye. Your doctor will let you know if you need to prepare for this ahead of time.
Even though fluoroscopy is not as commonly used today as it once was, it still has many valuable uses. It can serve as an adjunct to other, higher-resolution cross-sectional imaging modalities such as CT, MRI, and ultrasound. It can also be useful for the diagnosis of esophageal malignancy, particularly in conjunction with endoscopy, and it is a necessary tool in the pre- and post-treatment assessment of patients with gastroesophageal reflux disease. Additionally, it is a diagnostic modality capable of demonstrating morphologic abnormalities that might not be readily identifiable with pH monitoring alone. Lastly, it is an important tool for the training of radiology residents.
Ultrasound uses sound waves to produce images of the body. The test does not use ionizing radiation, and a physician can view the results in real-time. Doctors can also record the data for subsequent study. Unlike CT and MRI scans, ultrasound is relatively inexpensive and portable. It can be used to examine the heart, lungs and gallbladder, as well as other organs. Ultrasound is most commonly known for its role in fetal monitoring during pregnancy.
The technologist applies a gel to the skin and then moves a transducer over the area to be examined. The sound wave emitted from the transducer bounces off of the area and back to the probe, generating echoes that are recorded and displayed on the video monitor. The computer creates an image based on the intensity (amplitude) and pitch (frequency) of the returned signals and the type of body tissue the sound is passing through.
A doctor can adjust the probe position and frequency to better see certain areas of the body. A color-coded display allows the physician to easily identify various tissues and blood vessels. The procedure is also commonly used to examine tendons, muscles and ligaments, as well as the surfaces of bones. Often, doctors use musculoskeletal ultrasound to help with diagnosis of joint pain and injury. It is also useful for locating foreign objects such as needles during a procedure, such as a joint injection.
Although ultrasound has several advantages, it is not without its limitations. The sound waves do not pass well through air or bone, and so they cannot see some body structures obscured by these materials. Additionally, it can be difficult to accurately diagnose structures deep in the body because overlying fat attenuates the sound waves.
The FDA recommends that healthcare providers follow the principles of As Low As Reasonably Achievable (ALARA) when using diagnostic imaging technologies, including ultrasound. The agency cautions that ultrasound equipment does introduce energy into the patient’s body, which can cause physical effects such as pressure oscillations and a rise in temperature. This energy can lead to damage to tissues and cells.