Female, 21 years old, blurry vision for 6 months with Chiari I malformation on MRI, CSF flow study recommended. The cerebellar tonsils descend below the level of the foramen magnum, approximately 5 mm on the left and 7 mm on the right. The tonsils do, however, maintain their round morphology, and there is preservation of the CSF space posterior to the tonsils and anterior to the brainstem. CSF flow imaging is suboptimal despite an attempt to correct this by adjusting the technical parameters of the sequence. Given this limitation, there does seem to be robust flow anterior to the brainstem through the foramen magnum. There may be some degree of flow posterior to the spinal cord and along the cerebellar tonsils but this is difficult to assess with certainty.The remainder of the examination is unremarkable. Parenchymal morphology and attenuation are within normal limits. No areas of signal abnormality are suspected. No intracranial hemorrhage or abnormal extra-axial fluid is seen. The ventricles are normal in size.
Descent of the cerebellar tonsils as described above is compatible with Chiari I malformation. However, the cerebellar tonsils maintain a round morphology, and there is little if any actual crowding at the foramen magnum with preservation of CSF space both anterior to the brainstem and around the cerebellar tonsils. Therefore, the relevance of the Chiari malformation to the patient's presenting symptoms is unclear. CSF flow imaging is compromised by technical difficulties which could not be corrected at the time of scanning. The sequence, therefore, contributes little diagnostic information. If this information is felt to be necessary for clinical management, the patient may return to repeat the flow sequence only at no additional charge.