Magnetic Resonance Imaging (MRI) is a medical technology that uses powerful magnetic fields and radio waves to generate detailed pictures of internal body structures. Unlike X-rays or CT scans, MRI excels at visualizing soft tissues, making it invaluable for examining the brain, spinal cord, ligaments, and organs. Receiving your results involves two distinct components: the visual images themselves and the written report prepared by a radiologist. Understanding both the visual data and the structured medical language helps patients grasp what the scan has revealed about their health.
Visualizing the Scan: The Grayscale Images
The output of an MRI machine is a collection of images presented as thin, cross-sectional slices of the body. These images are always rendered in shades of grayscale, where the intensity of the signal from the tissues determines whether an area appears bright, dark, or intermediate. The machine captures these slices from multiple orientations, known as planes, to provide a complete three-dimensional view of the anatomy being scanned.
The three standard planes are axial (horizontal slices), coronal (vertical slices from front to back), and sagittal (vertical slices from side to side). Viewing the anatomy from these different angles helps radiologists precisely locate and characterize any abnormalities, ensuring no subtle findings are missed. The brightness or darkness of a tissue is referred to as its signal intensity.
Radiologists interpret the images based on two primary acquisition sequences, T1-weighted and T2-weighted, which highlight different tissue properties. On T1-weighted images, fat tissue appears bright, while fluid-filled areas like cerebrospinal fluid (CSF) or cysts appear dark. This sequence is particularly good for showing anatomical detail and the structure of organs.
The T2-weighted sequence is more often used to detect pathology because both fat and areas with high water content, such as inflammation, edema, or many tumors, appear bright. By comparing how a structure looks on both T1 and T2 images—for example, an area that is dark on T1 but bright on T2—radiologists can determine if a finding represents fluid, fat, or a disease process. Cortical bone, which has very few free-moving protons, appears dark on both T1 and T2 images.
Anatomy of the Written Report
The written MRI report is a standardized medical document drafted by the radiologist who interprets the images. It translates the visual findings into structured, technical language primarily intended for the referring physician. The report is organized into distinct sections, each communicating specific details of the exam and its results.
Clinical Indication/History
This initial section establishes the context for the scan by stating the reason it was ordered, often listing the patient’s symptoms or the diagnostic question the referring physician is trying to answer. The clinical indication helps the radiologist focus the interpretation on the relevant anatomy and potential pathology.
Technique
The technique section details how the scan was performed, including the specific imaging sequences used and whether an intravenous contrast agent, such as a gadolinium-based dye, was administered. Contrast agents are sometimes injected to make vascular structures, inflammation, or certain types of tumors stand out more clearly on the images.
Comparison
If the patient has had previous imaging studies of the same area, this section notes which prior scans the radiologist used for comparison. Comparing current images to older ones helps determine if a finding is new, stable, or has changed over time.
Findings
The Findings section is the descriptive core of the report, containing a detailed, system-by-system or region-by-region list of the radiologist’s observations. This part is typically dense with medical terminology, describing specific anatomical structures and noting any abnormalities, often using terms like “T2 hyperintensity” (meaning bright on T2-weighted images) or “hypointense” (meaning dark). For example, a radiologist might describe a lesion’s size, shape, and exact location within the scanned anatomy.
Impression/Conclusion
The Impression, or Conclusion, is the most concise and medically relevant part of the entire report for the patient and the ordering physician. This section summarizes the key findings from the descriptive section and provides the radiologist’s interpretation of their significance, often translating them into potential diagnoses or medical concerns. The impression may also include recommendations for further follow-up imaging, such as a repeat scan in six months, or suggest an alternative diagnostic test.
Translating the Findings to the Patient
After the radiologist has completed the report, the process shifts to communicating the results and their implications to the patient. For routine scans, the finalized report is typically sent to the referring doctor within 24 to 72 hours, though the patient may not hear the results until a follow-up appointment is scheduled. In cases where the scan reveals a finding that requires immediate action, the radiologist will often contact the ordering physician or the patient directly right away.
Patients can often access the written report and images through an online patient portal before their follow-up consultation. Reading the report without the context of the ordering physician, however, can lead to confusion because of the technical language and lack of clinical context.
The referring physician translates the radiologist’s Impression and applies it to the patient’s overall clinical picture. They integrate the imaging results with the patient’s symptoms, medical history, and physical examination findings to arrive at a final diagnosis. This consultation is where the next steps, such as treatment options, medication, or follow-up procedures, are discussed.