The Scan That Spoke: A Patient’s Journey With MRI Technology and Moyamoya Disease

---

“In 2021, I was exercising and all of a sudden I couldn’t move my left hand.” This was EA’s chief complaint, coming into the ER upon realizing that she was unable to perform everyday activities like athletics due to mobility in parts of her body, beginning with her left hand. Confused and panicked by the numbness and fatigue throughout her body, she visited the emergency room (ER). And within a few hours of being admitted to the ER, she had received a diagnosis, an answer to her questions: EA had Moyamoya Disease and had just experienced a stroke.

Those few hours in the ER were vital for her diagnosis because the hospital’s treatment team recommended tests like an angiogram, Computed Tomography (CT) scans, and finally a Magnetic Resonance Imaging (MRI) scan, the game changer in her treatment process. For EA, this medical technology method bridged the gap between concerning symptoms and a formal diagnosis.

Now 27 years old, EA, who works at a non-profit to help children enroll in preschool, looks back on her treatment journey six years ago and admits that although she knew little about MRIs and CT scans, just the basics from high school biology classes. Moyamoya Disease was a foreign name to her at the time.

Moyamoya Disease (MMD) is a rare neurological disorder in which cerebral arteries which supply blood to the brain become progressively narrowed, causing limited blood flow and inadequate oxygen supply to the brain. As a result, the brain develops many smaller blood vessels that appear fine and feathery like “puffs of smoke”, translating to moyamoya in Japanese. The narrowed arteries make the brain more vulnerable to strokes, as blood clots are more likely to block the arteries. People with MMD often experience a type of stroke called a transient ischemic attack (TIA), where blood flow is disrupted only for a few minutes at a time and results in paralysis on one side of the body for up to one day each time. It was during one of these mini-strokes that EA chose to receive medical examination at the hospital, allowing ER physicians to promptly recommend the use of special brain scans like the MRI scan to visualize blood flow through her brain’s blood vessels and identify brain areas with narrowed blood vessels.

Magnetic Resonance Imaging (MRI) is a non-invasive medical technology used for producing detailed two-dimensional anatomical images, relying on the magnetic properties of protons in the body. The National Institute of Biomedical Imaging and Bioengineering labels it as one of the prominent “technologies to shape the future of health” (Magnetic), explaining that MRI technology leverages the fact that much of the human body is made of water molecules, made of hydrogen and oxygen atoms that contain protons, neutrons, and electrons.

Patients like EA are placed inside an MRI machine, which contains magnets that produce a magnetic field, and the body’s protons align with this magnetic field. When a radiofrequency current is transmitted through the patient’s body, the protons spin out of equilibrium and strain against this magnetic field. Then, when the current is turned off, the protons realign with the magnetic field and energy is released in the process. MRI sensors embedded in the MRI machine can detect the amount of energy released and the amount of time required for the protons to return their alignment to the magnetic field. Variations in these energy and time quantities can differentiate between various types of tissues found in the body and brain. Even more crucial is the fact that MRI technology does not utilize harmful radiation that is often involved in CT scanning or x-rays, making it the safer imaging method for investigating symptoms in sensitive body sites such as the brain, especially when frequent repeated imaging was required to monitor EA’s condition over time. The magnetic differences produced a brighter or darker image in different brain areas, resulting in a black-and-white image of the brain. With this visualization of her brain’s structure, doctors now had the means to detect EA’s TIA strokes and identify the impacted blood vessels and brain, justifying the loss of function in her left hand.

EA vividly remembers the large MRI machine, being instructed to remain still for over 40 minutes during the scanning process. She notes that the treatment team warned her of the discomfort involved in the scanning process, including the machine’s noisiness, cold temperature, and the claustrophobic sensation it produced, giving her earplugs, a blanket, and a fidget toy ball to squish if she felt claustrophobic and wanted to exit the scanner machine. Yet despite the heads-up, she still remembers being startled by the machine being “really noisy and annoying…[and] also really cold.” Furthermore, she vividly remembers being told to remove all metal objects from her body as well as numerous fears related to the MRI device itself, pointing out that she “had the irrational fear that [she] accidently had a magnet in [her] pocket and [she] was gonna get smashed.” Despite these concerns, she is satisfied that the scan went smoothly and the resulting image proved useful during the diagnosis process.

EA joins millions of other individuals around the world who have been diagnosed with Moyamoya Disease through MRI technology, with clinical research indicating that high-resolution MRI techniques allow for differentiation between Moyamoya disease presentation and other similar arteriopathies, such as intracranial atherosclerotic disease (ICAD). Preliminary diagnostic tests typically involve a cerebral angiogram, an x-ray imaging method that depicts blood vessels in the brain, which focuses on the blood vessels’ lumen, or the hollow cavity in the vessels through which blood flows (NCI). A striking research finding is that visual images of the cerebral blood vessel lumen present similarly in patients with MMD and ICAD.

Although their blood vessel lumen presentation overlaps, the blood vessel wall presentation of MMD and ICAD do not -- and high-resolution MRI optimizes these blood vessel wall differences to make significant advances in MMD diagnosis. Since MRI imaging utilizes a magnetic field approach instead of x-ray radiation, it is able to directly visualize the shape and size of blood vessel walls of the small-sized middle cerebral artery. High-resolution MRI imaging has indicated that patients with MMD typically present with a smaller outer diameter of the MCA vessel wall on average, compared to the larger outer diameter of the MCA vessel wall for patients with ICAD. The MRI device’s ability to highlight these nuanced differences in blood vessel pathology make it the key to an accurate diagnosis of MMD and eliminating other similar medical conditions. This expands a medical professional’s diagnostic evidence beyond solely a patient’s medical history, which would provide an incomplete profile of the patient’s current condition.

Reflecting on the moment when doctors showed her the MRI scan results, EA shares that she believed the MRI was “pretty important because it helped doctors see what caused the stroke” and this imaging technology helped doctors provide an MMD diagnosis faster and with greater accuracy. With a confirmed diagnosis, EA could promptly undergo a surgical procedure which would reopen the narrowed blood vessels and thereby prevent more severe strokes in the future. Since her initial diagnosis, she has undergone followup MRI scans once every year to monitor her condition and ensure that “blood is flowing correctly in [her] brain.”

From a patient’s perspective, EA still acknowledges that the MRI imaging still has scope for improvement. She notes that seeing these images did not make her MMD diagnosis feel more real or understandable, partly because medical providers used “a lot of medical terms” which she could not fully comprehend, and she hopes for future patients to receive a more thorough explanation of MRI scan results so they can become more engaged in the treatment process. When asked what she would want medical students, engineers, or healthcare professionals to understand about the patient experience with MRI diagnostic technology, she would like providers to empathize with patients that the MRI scanning process is “a little scary first going into it” and she hopes for breakthroughs in development which will make MRI imaging “less noisy and more cozy” for herself and other patients who are required to undergo MRIs as part of their diagnostic or treatment process.

Much is left to be discovered about MRI technology and its potential to diagnose and monitor medical conditions like MMD. Aware that other imaging methods such as x-rays and CT scans are associated with poor health effects from ionizing radiation, EA expressed curiosity regarding the long-term consequences of these newer MRI imaging techniques. She shared that she would like doctors or engineers designing MRI devices to study “any negative effects to getting [an MRI] done,” providing relief and clarity to patients in her shoes who initially feel nervous and hesitant to enter the MRI scanner and undergo this imaging process. With MRI devices’ ability to distinguish between similar conditions such as MMD and ICAD, this imaging method also can be utilized to detect subtle neurobiological changes in the brain, providing a confirmed diagnosis when medical providers struggle to tell two similar conditions with overlapping symptoms apart. Only time will tell where MRI devices can take us, hopefully onto a path of declining misdiagnoses, increasing comfort, and ultimately a greater quality of life for patients around the world. †

Written by Editor and Staff Writer Sriya Bairy (sbairy@ucsd.edu)

Works Cited

Kang, et al. “Symptomatic Steno-Occlusion in Patients with Acute Cerebral Infarction:

Prevalence, Distribution, and Functional Outcome." Journal of Stroke, vol. 16, no. 1, 31

Jan. 2014, pp. 36–43, doi.org/10.5853/jos.2014.16.1.36. 

“Magnetic Resonance Imaging (MRI).” National Institute of Biomedical Imaging and

Bioengineering, U.S. Department of Health and Human Services,

www.nibib.nih.gov/science-education/science- topics/magnetic-resonance-imaging-

mri. Accessed 27 Mar. 2026. 

Moyamoya Disease | National Institute of Neurological Disorders and Stroke,

www.ninds.nih.gov/health- information/disorders/moyamoya-disease. Accessed 27

Mar. 2026.

“NCI Dictionary of Cancer Terms.” Comprehensive Cancer Information - NCI,

www.cancer.gov/ publications/dictionaries/cancer-terms/def/lumen. Accessed 27 Mar.

2026. 

Yu, et al. “High-resolution Magnetic Resonance Imaging of Moyamoya Disease.” Chinese

Medical Journal, vol. 128, no. 23, 5 Dec. 2015, pp. 3231–3237, doi.org/10.4103/0366-

6999.170257. 

 Image Credit: Magnetic Resonance Angiography of Moyamoya Disease by Wendy Walker, via Physiopedia (Creative Commons Attribution-Share Alike 3.0 Unported License)