Radiometric and Morphologic Analysis of Arnold Chiari Type-I Malformation and Idiopathic Syringomyelia: A Case Series from Pakistan

Background and objective: Chiari I Malformation-associated syringomyelia (CM) and idiopathic syringomyelia (IS) are often confused together. They require different diagnostic approach and treatment modalities; it is important to distinguish between the two. We aimed to evaluate the radiological and morphologic characteristics of CM and IS in adult and pediatric patients in Pakistani population.

Methods: Our retrospective case series was conducted at the Department of Radiology, Punjab Institute of Neurosciences assessing the operated cases of CM and IS cases from January 2022 to December 2023. Preoperative morphologic and radiological data was collected for adult and pediatric patients.

Results: Out of 16 patients, 75% were adults and four were children. Twelve patients were male. The mean age of adult patients at presentation was 30.50 ± 9.20 years. There were nine cases of Chiari I Malformation and seven cases of idiopathic syringomyelia. Craniocervical junction (CCJ) was the most common site of syrinx formation in adults (41.66%) in both Chiari I and IS groups. The mean size of syrinx in adults in IS was 7.842 ± 1.93 and in CM was 4.740 ± 0.45. Mean size of syrinx in children was 4.84 ± 0.48 mm. Moniliform shape was the most common form of syrinx in patients in both CM and IS groups.

Conclusion: In the Pakistani population, this study focuses on the radiological characteristics of idiopathic syringomyelia (IS) and Chiari I Malformation (CM), both of which commonly exhibit a moniliform syrinx. The craniocervical junction was frequently involved in CM, but IS exhibited a wider, bigger syrinx. Accurate diagnosis as well as treatment depend on imaging.