Neuroimaging and the Clinical Manifestations of Chiari Malformation Type I (CMI)

Abstract

Chiari malformation type I (CMI) involves the caudal displacement of the cerebellar tonsils through the foramen magnum with resultant brainstem compression in some individuals. Due to pathophysiologic changes, secondary conditions may arise, such as syringohydromyelia (SH) and scoliosis. This disorder is unique, as the diagnosis is confirmed through radiologic findings. At times CMI is discovered incidentally on neuroimaging, but more frequently a patient will present with specific symptoms, the most common being a prototypic occipital headache. Although the true etiology of this complex condition remains speculative, the advent of neuroimaging has allowed for clarification of the enigmatic relationship between cerebrospinal fluid (CSF) dynamics, neuroanatomical compression, and clinical symptoms. Recent advancements in magnetic resonance imaging (MRI) such as diffusion tensor imaging (DTI) and CSF flow studies show promise in clarifying the underlying fluid dynamics in CMI patients and can aid in the prognosis and diagnosis of this complex disorder.

Pediatric Chiari malformation type I: long‑term outcomes following small‑bone‑window posterior fossa decompression with autologous‑fascia duraplasty

“…In infants and children who are unable to communicate verbally, headaches may manifest as crying and irritability. Other common symptoms include non-radicular pain in the shoulder, back and extremities, motor and sensory disturbances, clumsiness, ataxia and lower cranial nerve dysfunction (29). In the current cohort, two patients with atrioventricular block were also identified.…”

“…Diagnosis of CM-I depends on MRI (29). For a long time, the diagnostic criteria have been under debate.…”

“…Patients with CM-I can be asymptomatic or can present with a variety of signs and symptoms ranging from headache to severe myelopathy and brain stem compression (29). With the increasing availability of diagnostic MRI, more asymptomatic patients are being identified (4).…”

Chiari I malformation and syringomyelia in mucopolysaccharidosis type I (Hurler syndrome) treated with posterior fossa decompression: Case report and review of the literature

“…[6] The most common type is CM-1, which is present in 0.56–1% of the population. [16] The radiologic diagnosis of CM-I is best made on cranial midsagittal MRI studies, with cerebellar tonsil herniation of at least 3 mm below the basion-opisthion line suggesting the condition [Table 1]. [31115] The symptoms of CM-I include head, neck, and back pain, cape pain (shoulders), nonradicular limb pain, weakness, paresthesias, vestibular symptoms, diplopia, tinnitus, hearing loss, syncope, slurred speech, dysphagia, urinary incontinence, and sleep disturbance.…”

“…[31115] The symptoms of CM-I include head, neck, and back pain, cape pain (shoulders), nonradicular limb pain, weakness, paresthesias, vestibular symptoms, diplopia, tinnitus, hearing loss, syncope, slurred speech, dysphagia, urinary incontinence, and sleep disturbance. [16] A syrinx is present in 30–70% of cases of CM-I. [15]…”