Understanding MRI Scans: What Patients Should Expect and How to Prepare

Magnetic Resonance Imaging (MRI) is one of the most sophisticated diagnostic technologies in modern medicine. By harnessing strong magnetic fields and radiofrequency waves instead of ionizing radiation, MRI provides unrivaled soft-tissue contrast, allowing physicians to detect subtle neurological disorders, torn ligaments, spinal herniations, and internal organ abnormalities.

How Does an MRI Actually Work?

Unlike conventional X-rays or CT scans that utilize ionizing radiation, an MRI scanner relies entirely on the natural water content of the human body. When you enter the magnetic bore, the scanner's powerful magnetic field (typically 1.5 Tesla or 3.0 Tesla) temporarily realigns the hydrogen protons in your body's water molecules.

Radiofrequency waves are then pulsed across the target area, knocking these protons out of alignment. As the radiofrequency pulse is turned off, the protons relax back to their original orientation, emitting faint signals. Sensitive receiver coils placed around your body detect these signals, and high-performance computers mathematically reconstruct cross-sectional 2D and 3D slices with microscopic precision.

Common Clinical Indications for MRI

At X-Ray Associates of Port Huron, our fellowship-trained radiologists review specialized MRI studies across diverse subspecialties:

• Neuroradiology: Evaluation of acute ischemic stroke, multiple sclerosis plaques, brain tumors, aneurysms, acoustic neuromas, and pituitary adenomas.
• Musculoskeletal (MSK): Rotator cuff tears, labral pathology in the shoulder and hip, ACL and meniscal tears in the knee, stress fractures, and cartilage degeneration.
• Spine Imaging: Disc herniation, spinal stenosis, sciatica, cord compression, and vertebral compression fractures.
• Body & Abdominal: Multiparametric prostate MRI (PI-RADS scoring), liver lesion characterization, pancreatic cystic neoplasms, and rectal cancer staging.
• Breast MRI: High-risk genetic screening (BRCA1/2 mutations) and silicone breast implant rupture evaluation.

Essential Patient Preparation Checklist

Proper preparation is critical to both diagnostic image quality and patient safety. Please adhere to the following guidelines:

1. Leave Metal at Home: Remove all jewelry, body piercings, watches, hairpins, hearing aids, dentures, eyeglasses, and belts with metal buckles. Even metallic threads in athletic clothing can heat up in the magnetic field.
2. Notify Staff of Implanted Devices: You will complete a comprehensive safety screening questionnaire. Alert the technologist if you have cardiac pacemakers, implantable defibrillators (ICDs), neurostimulators, cochlear implants, surgical vascular clips, or metallic fragments in your eyes from welding.
3. Eating & Drinking: For routine brain, spine, or joint MRIs, you may eat, drink, and take prescribed medications normally. For abdominal or pelvic scans, fasting for 4 hours prior may be requested.
4. Intravenous (IV) Contrast: If your exam requires gadolinium-based contrast to highlight blood vessels or inflammatory lesions, blood tests (eGFR) may be reviewed to confirm adequate renal function.

What Happens During the Examination?

The examination typically lasts between 20 and 45 minutes, depending on the body part and number of pulse sequences required. You will recline on a padded motorized scanning table. A specialized receiver coil (which looks like a plastic frame or vest) will be placed over the area of interest.

During scanning, you will hear loud rhythmic knocking, thumping, or buzzing noises. These sounds are completely normal and occur when the internal magnetic gradient coils shift rapidly. Earplugs or headphones playing music will be provided to ensure your comfort.

Overcoming Claustrophobia & Anxiety

If you experience anxiety in enclosed spaces, inform your ordering physician in advance. Your doctor may prescribe a mild oral sedative for you to take shortly before the scan (you will need a driver to escort you home). Our compassionate technologists maintain continuous two-way intercom communication and will provide a hand-held emergency call ball that you can squeeze at any moment.

Receiving Your Results

Immediately following your exam, hundreds of high-resolution digital image slices are sent to the Picture Archiving and Communication System (PACS) of X-Ray Associates of Port Huron. One of our board-certified, fellowship-trained radiologists will interpret each sequence, compare with prior studies, and deliver a formal written report directly to your physician within 24 hours.