Why do I need an MRI?

Headaches, lower back pain, swelling of the knee, heart palpitations? Are these every day health grievances, or are they warning signs of a more serious affliction? Depending on your specific circumstance, your doctor may recommend an MRI scan. As advancements in medicine continue to accelerate by leaps and bounds, how do you know if an MRI scan should be the next step in your treatment plan? Let's start answering that question with what exactly an MRI scan entails. 

What is an MRI?

Magnetic resonance imaging (MRI) is a widely utilized medical exam that captures images of the interior of the body. This system creates extremely detailed, high-resolution images of organs, bones, joints, and other soft tissues. An MRI scanner is a large, doughnut shaped machine with a table in the center on which a patient lies. The doughnut shape houses a very large and powerful magnet which is a key component to MR.

An MRI machine works because the human body is made mostly of water, which means there are countless hydrogen atoms inside our soft tissues. When an MRI machine is in use, it creates a magnetic field around the patient’s body that alters the natural alignment of the hydrogen atoms, causing them to line up and point in the same direction. Radio wave pulses are added to the magnetic field, causing them to spin randomly. When the radio wave sequences are halted, the atoms realign themselves to their normal positions and emit a radio signal. These signals are received and interpreted by a computer that then converts the information into images that can be examined by a radiologist.

Modern MRI technology can create three-dimensional, cross sectional images, often compared to slices in a loaf of bread.  Radiologists can interpret these images and easily differentiate between healthy and abnormal tissue.

Why Should I get an MRI?

Of the available medical imaging modalities, MRI scans provide high quality and accurate images. This clarity gives radiologists an enhanced view of any injury or condition that is ailing a patient. It also provides diagnostic confidence when assessing the condition and determining a treatment plan. Here are the advantages of an MRI scan:

  • MRI can show the precise location of any injury or tissue mass
  • MRI can characterize a mass as benign or malignant
  • MRI can demonstrate the number, size, and condition of abnormalities, and determine if metastasis has occurred
  • MRI is noninvasive and does not use ionizing radiation

MRI is a valuable tool due to its diagnostic and prognostic capabilities. MRI can be used to detect abnormalities, assess the condition, develop a treatment plan, and track its progress. This exam is most often used in the following anatomy areas:

  • Brain
  • Spinal cord
  • Heart and blood vessels
  • Internal organs
  • Bones and joints

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MRI of the brain and spinal cord

MRI is the most common imaging test for the brain and spinal cord. When imaging the brain specifically, a process known as functional MRI (fMRI) is used to determine the precise location in the brain where a certain function occurs, such as speech, movement, or memory.1 An fMRI is performed when the patient is conscious, and they are asked to perform small tasks, such as answering questions or tapping their fingers. This helps surgeons pinpoint the exact location of a functional area in the brain, allowing them to perform an operation more precisely.

A physician may order a brain MRI if their patient has sustained an injury to the head, or is demonstrating symptoms of dizziness, weakness, seizures, blurry vision, and chronic headaches. Brain MRIs provides information for several health conditions including:

  • Aneurysms
  • Hydrocephalus
  • Stroke
  • Tumors
  • Cysts
  • Traumatic injury

An MRI can also provide high quality images of the patient’s spine. Especially, the vertebrae that make up the spine, the ligaments that hold the vertebrae together, and the discs, spinal cord, and spaces between the vertebrae. In these cases, MRI helps determine the presence of structural abnormalities, such as tumors, multiple sclerosis, herniation, degeneration of discs, and congenital abnormalities.


In most cases, a physician will not refer a patient for an MRI unless they believe it necessary to better assess the patient’s condition and ultimately provide the best treatment of care. Based on both a clinical examination and a thorough understanding of the patient’s health history, a physician will then determine if MRI is the right option for them. While other imaging modalities can provide useful diagnostic information, the image quality and detailed valuable information gained with an MRI exam is significant and can help to develop a more personalized patient care plan. 




  1. "Magnetic Resonance Imaging of the Spine and Brain."John Hopkins Medicine. Web. 30 August 2018. <,P07651>.