Can Upright MRI Show Chiari Malformation and CCI?

It can be deeply frustrating to experience disabling positional symptoms—like headaches that worsen when you stand—only to be told your standard MRI is “normal.” For most patients, a conventional flat (supine) MRI is the gold standard for diagnosing a Chiari malformation and evaluating the brain and spinal cord ^[1]. However, for some patients, particularly those with joint hypermobility, an upright or dynamic MRI may be considered to answer specific clinical questions about how gravity and movement affect their anatomy ^[2].

When to Seek Immediate Care: Imaging takes time to arrange, but some symptoms require urgent medical attention. Seek emergency care for new or rapidly worsening weakness, trouble walking, loss of bladder or bowel control, difficulty breathing or swallowing, or sudden severe neurological changes.

Gravity and the Hypermobile Spine

In a healthy spine, strong ligaments hold the skull securely on top of the neck. In people with Ehlers-Danlos syndrome (EDS) or other connective tissue disorders, these ligaments can be excessively stretchy ^[3].

When you lie flat for a traditional MRI, the weight of your head is supported by the table, and the ligaments in your neck are not bearing weight. In this resting state, the brain and upper spine may sit in an anatomically normal alignment ^[2]. For some individuals, standing up puts stress on lax ligaments, potentially leading to cranial settling (altered relationships between the skull base and upper vertebrae) or changes in the position of the cerebellar tonsils (the lower part of the brain) ^[2][4].

Because of this, an upright MRI might reveal posture-dependent findings in selected patients ^[2]. However, a normal supine MRI is not automatically a “false negative.” Standard MRIs typically offer higher image resolution and remain the best way to evaluate the nervous system initially ^[1].

Types of Imaging Used

Understanding the difference between imaging tests can help you discuss them with your doctor. They are often used as complementary tools rather than replacements for one another.

Safety Note for Dynamic Imaging: If your doctor orders a flexion/extension scan, the movement should always be performed within a safe, comfortable range under supervision. Never force your neck into a painful position to try to get a “better” image, and tell the technician immediately if you experience severe pain, dizziness, or neurological symptoms.

Understanding Positional Findings

When interpreting upright or dynamic MRIs, specialists look for specific measurements. One common measurement is the clivo-axial angle (CXA), which measures the angle between the skull base and the spine ^[2].

While a significantly narrowed CXA can sometimes indicate that the brainstem is draped tightly over the bones of the spine, interpreting this is complex. Research shows that the CXA changes significantly depending on neck position, even in completely healthy people without any symptoms ^[6]. There is currently no universally accepted cutoff measurement that proves you have craniocervical instability (CCI) or definitively explains your symptoms ^[6][5]. Therefore, imaging findings must always be interpreted alongside a thorough physical examination ^[1].

The Bigger Picture: Syringomyelia and Dysautonomia

Evaluating the spine helps doctors see how Chiari malformation might interact with other conditions common in hypermobile patients:

• Syringomyelia: This is a fluid-filled cyst (syrinx) inside the spinal cord ^[7]. When Chiari malformation alters the normal flow of cerebrospinal fluid (CSF), it can contribute to the formation of a syrinx ^[7]. Because a syrinx can form anywhere in the spine, doctors frequently order a standard whole-spine MRI to evaluate for it ^[1].
• Dysautonomia: Many patients with Chiari and EDS experience autonomic nervous system dysfunction, such as Postural Orthostatic Tachycardia Syndrome (POTS) ^[3][8]. While some researchers hypothesize that mechanical stress on the brainstem might contribute to these issues, this is highly debated and unproven. POTS and dysautonomia can occur independently of Chiari or CCI, so it is vital to undergo a separate, dedicated autonomic evaluation rather than assuming your symptoms are solely caused by a structural spinal issue ^[3].