Assessment of 3D T2-weighted high-sampling-efficiency technique (SPACE) for detection of cerebellar tonsillar motion: new useful sign for Chiari I malformation

Clin Imaging. 2015 Jan-Feb;39(1):42-50. doi: 10.1016/j.clinimag.2014.08.011. Epub 2014 Oct 16.


Objective: To describe tonsillar blackout sign (TBS) on three-dimensional (3D)-SPACE, evaluate its performance in identifying Chiari malformation (CM1) as diagnostic marker, and investigate its role in differentiation of symptomatic and asymptomatic CM1.

Methods: One-hundred fifty-six patients were divided into two groups based on caudal displacement of cerebellar tonsils: CM1 (Group I) and non-CM1 (Group II). Group I was subclassified as symptomatic and asymptomatic by a neurosurgeon. Two radiologists evaluated TBS and cerebrospinal fluid flow abnormality.

Results: All subjects presenting TBS had CM1. Difference in presence of TBS between Group I and Group II was highly significant (P<.001).Grading of TBS in symptomatic patients was significantly higher than that in asymptomatic patients (P<.001).

Conclusion: TBS is highly suggestive of CM1 and potentially useful in differentiation of symptomatic and asymptomatic CM1.

Keywords: 3D T2-weighted high-sampling-efficiency technique (SPACE); CSF flow MR imaging; Chiari I malformation; Tonsillar motion.

Publication types

  • Evaluation Study

MeSH terms

  • Adult
  • Arnold-Chiari Malformation / diagnosis*
  • Cerebellum / pathology*
  • Female
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Young Adult