Reliability of the STIR sequence for acute type II odontoid fractures.

BACKGROUND AND PURPOSE: The STIR sequence is routinely used to assess acute traumatic osseous injury. Because the composition of the odontoid in older individuals may be altered with osteopenia and decreased vascularity, the STIR sequence may not accurately depict the acuity of an odontoid fracture. The purpose of this study was to evaluate the reliability of the STIR sequence to differentiate acute-versus-chronic type II odontoid fractures in older patients, particularly those with osteopenia. MATERIALS AND METHODS: A retrospective review was performed for patients with type II odontoid fractures during a 10-year period with both CT and MR imaging performed within 24 hours of injury. Patients were paired with controls of similar ages and were grouped by age. The STIR images were evaluated in a blinded fashion for the presence of hyperintensity in the odontoid. Demographic and clinical characteristics were also recorded. RESULTS: Seventy-five patients with type II odontoid fracture and 75 healthy controls (mean and median age of 57 years) were identified. The sensitivity of STIR to detect fracture in the age group 57 years and older was significantly worse than that in the age group younger than 57 years (54% and 82%, respectively; P = .018). CONCLUSIONS: Older patients, particularly those with osteopenia, may have acute odontoid injuries without corresponding STIR hyperintensity. Additionally, interobserver agreement in STIR interpretation decreases with increasing patient age. As such, in this patient population, in which the presence of bone marrow edema as an indicator of fracture acuity may impact therapeutic decisions, correlation with CT findings and clinical history is crucial.

The Pittsburgh study of normal sleep in young adults: focus on the relationship between waking and sleeping EEG spectral patterns.

The effects of age and gender on spectral characteristics of the waking EEG were investigated in a large sample of young adult men and women. In addition, relationships between spectral characteristics of the waking and sleeping EEG within an individual were explored. The sample included 28 females and 33 males in two age groups: 20-29 years (n = 32), and 30-40 years (n = 29). Spectral analysis was used to quantify EEG frequency characteristics for waking EEG just prior to sleep onset, as well as for the entire sleep recording. Significant effects of age were seen in the waking EEG but only in the delta frequency range (0.5-4.5 Hz) with lower delta activity in the older group (F = 11.6, P = 0.001). No significant gender effects were found in the waking EEG. Independent of age and gender, spectral profiles in the delta, theta, alpha and beta frequency bands of a subject's waking EEG were found to be highly correlated with their sleep EEG. In addition, subjects with high voltage alpha profiles during waking were found to sleep significantly longer and deeper than those with low voltage records. Significant correlations between waking and sleep EEG suggest that the spectral signature of an individual's EEG may be found across sleep/wake states.