- Bayer Indonesia
Finding a disease early on can have a great impact on treatment. A doctor must know their patient’s specific disease, as well as how far the disease has progressed, before they can develop a treatment plan.
A picture with power
Often it starts small - a tingling, a non-specific pain, lethargy or just not feeling “right.” The next step is usually a visit to a doctor for advice. This can be the start of a long journey of blood tests and monitoring clinical symptoms. In some cases, diagnostic imaging may be required to either exclude the possibility of a specific disease or identify the cause of symptoms. This might mean an ultrasound procedure, an X-ray, a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan is ordered to complement initial findings with a view inside the body. In many cases, a detailed picture of an inner part of the body helps to determine the best treatment.
The diagnostic imaging technique chosen will depend on the part of the body being examined, the amount of time available (e.g., emergency cases), the age of the patient and/or certain patient characteristics that might not permit a particular scan. The radiologist will decide whether or not to use a contrast agent, and whether to administer it by hand or by an injector.
Once a medical imaging scan has been performed, the radiologist will study the image and provide a formal assessment and recommendation to the treating doctor who will discuss the results with the patient during a follow-up appointment.
Diagnostic imaging techniques
- Computer Tomography (CT)
A CT scan combines a series of X-ray images taken from different angles and provides more detailed information than a two-dimensional X- ray.
A CT scan is particularly well-suited to quickly examine people in emergency situations due to its fast image acquisition time. A CT scan can be used to visualize nearly all body parts, and is used to find and characterize a disease or injury, as well as to plan medical, surgical or radiation treatment.
Your doctor may recommend a CT scan to help:
- Diagnose muscle and bone disorders, such as bone tumors and fractures
- Find and localize a tumor, infection or blood clot
- Guide procedures such as surgery, biopsy and radiation therapy
- Detect diseases and monitor progression in conditions such as cancer, heart disease, lung nodules and liver masses
- Monitor treatment success
- Detect internal injuries and internal bleeding
During a CT scan, patients are briefly exposed to ionizing radiation. The amount of radiation is higher than a plain X-ray because a CT scan is compiled of multiple X-ray scans from different angles, providing more detailed information.
Recent technical innovations have contributed to lowering the radiation dose from CT scans. The physician will assess, however, the benefits and risks of a CT scan depending on the patient’s medical history.
The radiologist will determine whether adding a contrast agent during a CT procedure is needed or indicated. A contrast agent is needed for some CT scans to help highlight the areas of the patient’s body being examined.
A contrast agent might be given:
- By mouth: If your esophagus or stomach is being scanned, you may need to swallow a liquid contrast agent.
- By injection: A contrast agent is injected through a vein to help certain organs or blood vessels stand out in the scans.
- By enema: A contrast agent may be inserted in your rectum to help visualize your intestines.
Managing radiation dose
It is the radiologist’s goal to determine the lowest possible radiation dose while achieving the highest quality diagnostic image. With this in mind, both contrast dose and radiation dose need to be carefully managed.
Reactions to a contrast agent in CT
In certain cases, your doctor may recommend you receive a contrast agent during the CT imaging procedure. Although rare, a contrast agent can cause medical issues or allergic reactions. The imaging procedure, including the potential use of contrast, will be explained by the radiologist, and patients will be informed about their individual risk-benefit ratio. Tell your doctor if you've ever had a reaction to a contrast agent.
Magnetic resonance imaging (MRI)
MRI is a type of medical imaging used to examine almost any part of the body. MRI can be used to help diagnose a variety of medical conditions from concussions to cancers, or assess how well a current treatment is working and plan future treatments. It’s commonly used to diagnose diseases and injuries in the brain, spine, abdomen, pelvis and joints. It can also detect blockages in blood vessels, as well as swelling or inflammation. MRI helps doctors choose the best available therapy and see if it’s working or needs to be altered.
Most MRI machines are large, donut-shaped magnets. When lying inside an MRI machine, the magnetic field temporarily realigns hydrogen atoms in their body. Radio waves cause these aligned atoms to produce very small signals, which are used to create cross-sectional MRI images.
When the patient goes into the scanner, the magnet aligns the hydrogen atoms in the body so they point in the direction of the magnetic field. A very short pulse of radio waves is then turned on, which makes the atoms temporarily change orientation. After the radio waves are switched off, the hydrogen atoms realign, giving off tiny radio signals that are picked up by the coil (a radio antenna) which is placed around the part of the body being imaged. This is all completely painless, and the patient is never aware that it is happening.
The MRI technologist will operate the scanner from a separate room, using a computer that is kept away from the magnetic field created by the MRI scanner. The technologist will talk with the patient through an intercom system.
Although there are no moving parts, there are magnets inside the MRI scanner that are switched on and off quickly. This causes them to vibrate, which produces the knocking sounds that are heard when it’s working. This is perfectly normal and part of the imaging process. The patient will be given earplugs or headphones to manage the noise.
Depending on the part of the body being scanned, patients will enter the scanner either head or feet first. The scan will last between 15 and 90 minutes, depending on the size of the area being scanned and the number of images being taken. Once the scan is over, a computer converts the data into the detailed image that the radiologist analyzes. The results allow the radiologist to determine whether adding a contrast agent during an MRI procedure is needed.
An MRI contrast agent is a colorless liquid which is used to improve image quality. It makes parts of the image appear brighter and increases the level of detail on the scan. This helps doctors make a faster and more reliable diagnosis.
A small amount of a contrast agent will be injected during the scan, either by hand or by a pump called an “injector.” In some cases, a patient might experience a cold feeling in their arm – this is normal and dissipates shortly.
Injectors help to manage when, how much and at what rate a contrast agent is administered through the vein while an image is captured. All these factors can impact quality of the resulting image. Smart and connected devices – for instance, injectors that are able to collect and distribute contrast media dose information – can help radiologists to improve quality and care aspects.
Reactions to a contrast agent in MR
In certain cases, doctors may recommend patients receive a contrast agent during the MRI procedure. While injecting a MR contrast agent, there is the possibility of adverse effects. Although rare, contrast can cause medical issues or allergic reactions. The imaging procedure, including the potential use of a contrast agent, will be explained by the radiologist, and patients will be informed about their individual risk- benefit ratio. Patients should tell their doctor if they’ve ever had a reaction to a contrast agent.
A contrast agent in CT and MRI is used to enhance image quality, reveal more information, identify small lesions, or characterize and differentiate certain tissue structures. A contrast agent for CT is based on iodine while an MRI contrast agent uses Gadolinium molecules.
Injectors help to manage when, how much and at what rate a contrast agent is administered through the vein while an image is captured. All these factors can impact the quality of the resulting image. Smart and connected devices – for instance, injectors that are able to collect and distribute contrast media dose information – can help radiologists to improve quality and care aspects.
Advice for patients : Each body reacts differently to medicines. Therefore, it is impossible to tell which medicine works best for you. Please consult your physician.