Evaluation of apparent diffusion coefficients in the cerebellar tonsils and bulbus in chiari type i malformations: comparison before and after surgery
Year: 2017
Type: article
Abstract: Computerized tomography and conventional magnetic resonance imaging (MRI) have been used to show many structural alterations that can either develop because of, or accompany, CMI.These include cerebellar tonsillar herniation, small posterior fossa volume, basilar invagination, occipitalization of the atlas, hydrocephalus, and syringomyelia (4,9,15).In addition, many specific morphometric findings have been reported, such as a shallow posterior cranial fossa, short anteroposterior length of the foramen magnum, and a large angle of the tentorium (4).Although correlations have been confirmed between these structural alterations and clinical presentations in various studies, the degree of tonsillar herniation has not always been compatible with the █ INTRODUCTIONT ype 1 Chiari malformation (CMI) is the most common Chiari malformation, and is characterized by caudal displacement of the cerebellar tonsils into the cervical canal through the foramen magnum.The clinical signs and symptoms of CMI are believed to be manifestations of these anatomical changes.Consistent with this, patients with CMI exhibit various clinical signs and symptoms, due to cerebellar signs, brainstem compression, cranial nerve dysfunction, and spinal cord injury.Prominent examples include head, neck, back, and limb pain, as well as limb movement disorders, spasticity, sensory disturbances, vertigo, ataxia, nystagmus, and dysphagia (5,9,16).AIM: To evaluate the preoperative and postoperative 6 th month mean apparent diffusion coefficient (ADC) values of the cerebellar tonsils and bulbus in patients with Chiari Malformation Type I (CMI), and to compare the results with healthy controls. MATERIAL and METHODS:We included 15 patients with CMI who underwent suboccipital decompression, upper cervical laminectomy, and duraplasty surgery, and compared them with 10 healthy individuals.Three regions of interest were placed, one each in the cerebellar tonsils and one in the bulbus.The mean ADC values were measured separately in each region.RESULTS: Among the patients, mean ADC values were significantly decreased after surgery compared with before surgery.The mean ADC values before surgery were significantly higher for patients than for controls; however, although the mean ADC values were slightly higher after surgery for patients than for controls, the differences were not significant.Thus, after surgical intervention, ADC values in patients with CMI became close to those of normal individuals. CONCLUSION:The increased ADC values in patients with CMI before surgery implied that not only morphologic changes but also increased diffusivity may play a key role in the pathophysiology and clinical presentation of the disease.Decompression surgery can produce favorable diffusional alterations.
Source: Turkish Neurosurgery
Institution: Fırat University
Language: English
Subfield: Clinical Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2777065670