Understanding how long medical imaging scans take can help ease anxiety and prepare patients for a smoother experience. Whether you're scheduled for computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound, knowing the typical duration and what factors may affect it can provide peace of mind. This guide will walk you through the expected time frames for each type of scan and factors that may influence how long your appointment will last.

How Long Do CT, MRI, and Ultrasound Scans Take? A Patient's Guide

CT Scans: Quick and Efficient Imaging

CT scans are crucial diagnostic tools that provide detailed, cross-sectional images of the body, allowing physicians to accurately diagnose and treat a wide range of conditions.

What is a CT Scan?

CT scans are a standard medical imaging procedure in which a narrow beam of X-rays is rotated around the patient’s body, producing signals that are processed to create cross-sectional images. These images are stacked to form a three-dimensional image of the tissue of interest. CT scans excel at imaging dense structures such as bone, while soft tissues can be more challenging to visualize. In some instances, contrast agents can enhance the visibility of soft tissues or blood vessels.

Typical uses of CT scans include: 

• Imaging the heart in cases of suspected heart disease or abnormalities. 
• Lung cancer screening or imaging to detect tumors, abnormalities, blood clots, or other conditions. 
• Imaging the head to identify head injuries, brain tumors, clots, hemorrhage, or other conditions. 
• Imaging bones to investigate complex fractures or identify signs of osteoporosis. 
• Identifying potential tumors or other abnormalities in the abdomen.

Typical Duration of a CT Scan

CT scans are relatively quick and easy and last between 15 and 30 minutes, including preparation and scan time. 

• Preparation Time: Preparing for a CT scan is quick for most people, taking 5 to 10 minutes. Patients are often required to change into a gown and remove anything metal, such as jewelry, which could interfere with the scanner. 
• Scan Time: A CT scan typically takes between 10 and 20 minutes, depending on the area being scanned and the number of images required. The patient will generally lie still on a bed that moves into the CT scanner. 

Factors Affecting CT Scan Time

Several factors can affect the time a CT scan takes and extend its duration, including: 

1. Administration of contrast material. If a contrast agent is required, it will be administered either as a drink, by enema, or via injection and can add 10 to 20 minutes to the preparation time. Additionally, you may be asked to drink a certain amount of water before the scan.
2. Blood tests. Some people may need a blood test before administering contrast agents to ensure they will not lead to adverse effects. This can add a considerable amount of time to the total appointment time. ‍
3. Additional scans. In some instances, multiple scans of different areas or from different angles must be taken in a single appointment. In other cases, excessive patient movement may cause the scans to blur, necessitating repeat scans.

MRI Scans: Detailed Imaging with a Longer Duration

What is an MRI Scan?

An MRI scan is another advanced imaging technique that uses strong magnets and radio waves to create detailed pictures of the inside of the body. When you lie in an MRI machine, the magnets cause hydrogen atoms in your body to line up. The machine then sends radio waves that temporarily disrupt this alignment. As the atoms return to their original positions, they release energy, which the MRI scanner detects. Different tissues in the body give off different signals, allowing the machine to create detailed images of organs, muscles, and other internal structures.

Unlike CT scans, MRI scans effectively image soft tissues, such as muscles, tendons, and ligaments. Common uses of MRI scans include brain and spinal cord imaging, examining knee and other injuries, and detecting abnormalities in breasts, heart and blood vessels, and internal organs such as the liver, womb, or prostate gland. 

Ezra’s full-body MRI scans the following organs: 

• Brain
• Spine
• Thyroid
• Liver
• Gallbladder
• Pancreas
• Spleen
• Kidney
• Adrenal gland
• Bladder
• Ovary
• Uterus
• Prostate gland

Typical Duration of an MRI Scan

MRI scans typically take longer than CT scans but provide highly detailed images of numerous organs. Depending on the area being scanned, an MRI scan will take between 20 and 100 minutes. 

• Preparation Time: Like a CT scan, preparation for an MRI usually takes 5-10 minutes and requires changing into a hospital gown and removing metal objects.
• Scan Time: The scan time depends on the size of the area being scanned and the number of scans required, but it usually lasts 15-90 minutes. Ezra’s full-body MRI scan takes approximately one hour and requires patients to lie still on a bed while scans are taken. 

Factors Affecting MRI Scan Time

Several factors can impact the duration of an MRI scan, including: 

1. Administration of a contrast agent. Like CT scans, contrast agents are sometimes required to enhance MRI scans. This can add around 10 to 20 minutes to the total time and can necessitate a blood test, which adds additional preparation time. 
2. Scan complexity. Complex scans, scanning multiple areas of the body, or the requirement for higher resolution images can extend the time taken for scanning. 
3. Patient movement or claustrophobia. Excessive movement can mean that scans need to be retaken. Moreover, patients with claustrophobia may require additional time to familiarize themselves with the machine, ask more questions, or be administered a sedative in severe cases. 

Ultrasound Scans: Quick and Non-Invasive

What is an Ultrasound Scan?

‍Ultrasound scans use high-frequency sound waves to examine internal body structures. The sound waves are directed at the tissue of interest, and the reflected sound or echo is recorded, converted into electrical impulses, and processed to form an image. 

Ultrasound scans can be external, where the probe is moved over the skin, internal, where the probe is inserted into the body, or endoscopic, where the probe is attached to a long, flexible tube, allowing it to be passed further into the body. Ultrasound scans are most commonly known for their role in monitoring unborn babies, but they can also be used for diagnosing certain conditions or guiding surgeons during procedures. 

Typical Duration of an Ultrasound Scan

Ultrasound scans are relatively quick, usually lasting between 20 and 50 minutes. 

• Preparation Time: Preparing for an ultrasound scan can involve changing clothes, depending on the location of the scan, and applying gel. It typically takes around 5 minutes.
• Scan Time: The scan generally lasts 15 to 45 minutes, again depending on the location of the scan and clarity of the images. 

Factors Affecting Ultrasound Scan Time

Factors Affecting Ultrasound Scan Time

1. Scan type and complexity. The type of ultrasound scan can impact the time taken for numerous reasons. For example, it can take longer if multiple areas need to be examined in a single scan. Additionally, for endoscopic examinations, patients are usually administered sedatives and anesthetic spray to numb the throat, which can add extra time to the process. 
2. Patient-specific factors. Ultrasound imaging can be impacted by patient-related factors such as body habitus; in certain people, it may take longer to obtain clear images. 

Comparing the Duration of CT, MRI, and Ultrasound Scans

The choice between CT, MRI, and ultrasound is generally made by the clinical practitioner, depending on several factors, including the organ or tissue being imaged and the time available. For example, in emergency situations such as acute trauma, CT scans are often preferable due to their ability to provide fast results. Meanwhile, MRI scans are often preferable in more complex cases as well as routine screening due to the detail of the images generated and the lack of ionizing radiation making them more suitable for regular screening. Ultrasounds are the first choice for monitoring pregnancies, and they are also highly useful for guiding other procedures like biopsies. 

Average Time Comparison

CT Scan

• Preparation Time: 5-10 minutes
• Scan Time: 10-20 minutes
• Total Time: 15-30 minutes

MRI Scan

• Preparation Time: 5-10 minutes
• Scan Time: 15-90 minutes
• Total Time: 20-100 minutes

Ultrasound Scan

• Preparation: 5 minutes
• Scan Time: 15-45 minutes
• Total Time: 20-50 minutes

Conclusion

The duration of CT, MRI, and ultrasound scans varies based on the type of scan and the area being imaged. Knowing what to expect can help ease any concerns about the timing of your scan and reduce general scan-related anxieties. For any specific questions or details about your upcoming scan, it's always best to consult your healthcare provider to ensure a smooth experience.