Cine MRI

Cine MRI

Cine MRI – Understanding CSF Flow Imaging

A Cine MRI (cine phase-contrast MRI), pronounced “sin-ee” is a specialized type of magnetic resonance imaging that captures moving images, allowing doctors to observe the flow of cerebrospinal fluid (CSF) and other dynamic processes in real-time. “Cine” is derived from the word “cinema,” reflecting its capability to create a series of images that show motion, similar to a movie.

This MRI is taken the same way as a traditional MRI, with the addition of either a wristband or EKG leads on the patient’s chest to measure the heart rate. Each time your heart beats, the cerebrospinal fluid is forced out of your brain, down toward the spine in response to the flow of blood that enters the brain with each beat. The MRI machine is equipped with an additional software package that allows the images to be put together, showing the flow of the cerebrospinal fluid (CSF) as it is moving.

Cine MRI - A specialized type of magnetic resonance imaging

Procedure:

  • Preparation: The patient is positioned in the MRI machine, similar to a standard MRI procedure. They may need to hold their breath or follow specific instructions to ensure clear images.
  • Imaging: The MRI scanner uses magnetic fields and radio waves to create detailed images. For cine MRI, the scanner takes multiple images over a period, creating a sequence that shows movement.
  • Analysis: Radiologists and specialists analyze the cine MRI images to determine the amount of fluid that is moving and compare that with normal subjects.

Cine MRI Usage in Chiari Malformation Diagnosis:

  • CSF Flow Assessment: Cine MRI is particularly useful in Chiari malformation for evaluating the flow of CSF at the foramen magnum (the opening at the base of the skull). It helps determine if the herniated cerebellar tonsils are blocking CSF flow, which could result in syringomyelia or hydrocephalus. The presence of these additional symptoms can guide treatment decisions.
  • Chiari 0: Cine MRI’s can be useful in cases of “borderline” Chiari malformations or when the question of whether or not decompression is needed is not readily answered using a traditional MRI.
  • Pre- and Post-Surgery: It can be used both before and after decompression surgery to evaluate the effectiveness of the procedure in restoring normal CSF flow.

Cine MRI scans are not as widely available as standard MRI scans. This limited availability can be due to the specialized nature of the equipment and expertise required to perform and interpret cine MRI studies. The practical use of cine MRI in clinical practice is still a topic of debate among physicians. Some clinicians find it valuable for diagnosing and managing conditions like Chiari malformation and hydrocephalus, while others question its necessity and cost-effectiveness compared to other diagnostic methods.

Radiology in the Diagnosis of Chiari I Malformation

by Victor Haughton, MD, University of WI-Madison

For some patients with the Chiari I malformation CSF flow studies may be helpful in determining if surgical management is appropriate. Some patients with a Chiari malformation may not need the flow studies.

The position of the tonsils can be evaluated by a routine MR scan or even a CT scan, making the identification of the Chiari I malformation simple. The definition of the Chiari I malformation for radiologists is the descent of the tonsils 5 mm below the foramen magnum. Although this amount of tonsilar malposition is found once in approximately every 150 scans, it is not always a finding that needs to be evaluated further or treated. In some cases, it is an incidental finding, that is not related to the conditions or symptoms for which the scan was requested. In other cases, the finding may explain the patient’s symptoms or conditions. For example, in patients with Valsalva-induced headaches (exertional headaches), syringomyelia (spinal cord cysts), apneic spells (temporary interruption of breathing pattern), the Chiari I malformation can be diagnosed as the cause of the symptoms with a high degree of confidence. In other patients, having MR because of a pituitary disorder for example, the low position of the tonsils does not likely relate to the patient’s symptoms. In many cases, the patient’s signs and symptoms may not be easily attributed to one cause and not confidently explained by the tonsil position. Such patents might include patients with less distinctive types of headaches for example.

Therefore CSF flow studies have been developed to provide a functional test of the effect of the tonsils, to distinguish the “symptomatic Chiari I” (with symptoms resulting from the tonsil position) from the “asymptomatic Chiari I” (with symptoms or symptoms unrelated to the tonsil position). The usual test of CSF flow is the cardiac-gated Phase Contrast MR study (PC MR). This study shows the pattern and measures the velocity of CSF flow. The study may be viewed as a cine loop showing the changes in CSF flow during the cardiac cycle, or it may be viewed as a series of images representing different phases in the cardiac cycle. The images may be analyzed to measure the velocity of the CSF and, with sophisticated mathematical techniques, the pressures, pressure waves, flow directions, and flow structure.

PC MR shows different CSF flow patterns in Chiari I patients than in normal subjects. It shows different patterns in “symptomatic” than in “asymptomatic” patients). In PC MR, the symptomatic patients display “synchronous bidirectional flow” and greater CSF velocity magnitudes compared to the “asymptomatic patients. PC MR has good but not perfect accuracy (1). The PC MR test for abnormal CSF flow should include axial images at the tip of the tonsils and perhaps sagittal images.

New research suggests that the accuracy of the test may be improved by obtaining axial PC MR images at multiple levels. The goal of research is to define the critical CSF flow parameters that result necessarily in signs and symptoms. Sophisticated techniques, Computation Flow Design, are used by some investigators in attempt to explain how obstruction of CSF flow by the tonsils results in a syrinx, spinal cord cyst, inches below the obstruction. These studies are enhancing our understanding of CSF flow and promising to improve our diagnosis and care of the Chiari I malformation.

Related Videos

Learn more about the role of radiology in CM/SM from these expert presentations at ASAP conferences:

Craniocervical Anatomy in Black & White – Carina Yang, MD

The Fundamentals of Chiari & Syringomyelia from a Neuroradiologist’s Perspective – Carina Yang, MD

Advanced Imaging Technologies & AI for Chiari Malformation & Beyond – Moss Zhao, DPhil

A Glimpse Inside the MRI of Chiari, Syringomyelia & Related Disorders – Carina Yang, MD

Engineering-based Diagnostics for Assessment of Chiari Malformation – Gwen Williams, MD

References

  1. Hofkes SK, Iskandar BJ, Turski PA, Gentry LR, McCue JB, Haughton VM. Differentiation between symptomatic Chiari I malformation and asymptomatic tonsilar ectopia by using cerebrospinal fluid flow imaging: initial estimate of imaging accuracy. Radiology. 2007 Nov;245(2):532-40. Epub 2007 Sep 21.