Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging technique. It uses strong magnetic fields and radio waves to generate detailed images of organs, soft tissues, bone, and other internal body structures. Patients often inquire about the expected duration of an MRI scan.
Typical MRI Scan Durations
MRI scan durations vary, though most procedures range from 15 to 90 minutes. The specific body area being examined is a primary determinant. For instance, a shoulder MRI might take 15 minutes, while a comprehensive cardiac MRI could extend to 90 minutes. Brain and spinal cord scans typically fall within 30 to 60 minutes.
Abdominal MRIs can take 30 to 90 minutes, though some detailed scans might last up to two hours. Breast MRIs usually require 30 to 60 minutes. Knee, ankle, and hip MRIs often take 25 to 60 minutes, depending on the required detail.
Key Factors Influencing Scan Time
Several factors influence MRI scan time. The specific body part scanned directly impacts duration, as different anatomical regions necessitate distinct imaging sequences and views to capture comprehensive detail. For example, a brain MRI involves different protocols than a knee MRI, leading to varying scan times.
The complexity of the examination also plays a role; a scan focusing on a single area for a routine check-up will be quicker than one requiring multiple areas or a highly detailed investigation. If a contrast material, such as gadolinium, is administered intravenously, additional scan sequences are performed after the injection, which can add 15 to 30 minutes to the total procedure time.
Patient movement during the scan can significantly prolong the process. Any motion can blur images, requiring sequences to be repeated to achieve diagnostic quality. If a patient, such as a child or someone experiencing claustrophobia, requires sedation to remain still, additional time is needed for the administration of the sedative and monitoring. The technologist operating the MRI machine may also need to make adjustments to imaging sequences based on initial images, which can add a few minutes to the overall scan.
Preparing for Your MRI
Proper preparation helps ensure a smooth and efficient appointment. Patients are advised to arrive 15 to 30 minutes before their scheduled scan to complete paperwork and change into a hospital gown. This allows ample time for administrative procedures and reduces delays.
Given the powerful magnetic field, it is essential to remove all metal objects prior to the scan. This includes jewelry, watches, hairpins, eyeglasses, dentures, hearing aids, and clothing with metal zippers or fasteners. Patients are asked to disclose their medical history, including any implanted devices like pacemakers or artificial joints, allergies, and claustrophobia, as these details are important for safety and scan planning.
Specific dietary restrictions, such as fasting, may be required for certain MRI scans, particularly if contrast material is used or if the abdomen is being imaged. Instructions regarding eating and drinking are provided in advance if applicable.
What to Expect During the Scan
During the MRI scan, patients lie on a motorized table that slides into a large, cylindrical machine. The machine is open at both ends, and patients may enter head-first or feet-first depending on the body part. The MRI machine produces loud tapping, thumping, and knocking noises as it operates, which are normal. Earplugs or headphones are provided to reduce the noise.
Maintaining absolute stillness throughout the scan is crucial for clear, high-quality images. The technologist may provide instructions, such as holding your breath for short periods, to ensure image clarity. An intercom system allows continuous two-way communication between the patient and the technologist, who monitors the scan from an adjacent control room. While the procedure is generally painless, the enclosed space can cause anxiety for some individuals. The scan is composed of multiple short sequences, each lasting a few seconds to a few minutes, rather than one continuous long scan.