MR evaluation of Chiari I malformations at 0.15 T

• Published in: American journal of neuroradiology : AJNR 1985, Vol.6 (2), p.203-208
• Main Authors: SPINOS, E, LASTER, D. W, MOODY, D. M, BALL, M. R, WITCOFSKI, R. L, KELLY, D. L. JR
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Malformations of the nervous system; Medical sciences; Neurology
• ISSN: 0195-6108; 1936-959X

Twelve patients with known or presumed Chiari I malformations and two with clinical diagnoses of multiple sclerosis were examined by magnetic resonance (MR) imaging. MR confirmed or established the diagnosis of Chiari I malformation in all 14 cases. The spin-echo technique with a short time to echo (TE = 40 msec) and a short time to recover (TR = 1000 msec) provided optimum imaging of tonsillar position, hydromyelia cavities, and cervicomedullary “kinking.” Long TE (>80 msec) and TR (>2000 msec) increase the signal intensity of cerebrospinal fluid and may obscure the pathology. Sagittal, transaxial, and coronal images provided complementary data; sagittal and coronal views best imaged the abnormal spinal cord and tonsils, but slitlike cavities were best seen on transaxial images. Cervicomedullary kinking was found in 10 (71%) of 14 patients and in 90% of the hydromyelic patients. This high incidence suggests that in other radiologic techniques tonsillar herniation masks the kinking. Symptoms of the Chiari I malformation overlap those of demyelinating diseases and brain tumors. Our early experience suggests MR is the preferred noninvasive procedure for identifying Chiari I malformation. Moreover, the ability to portray the variable cavity morphology of hydromyelia directly offers the potential for improved shunt placement.