A stationary hemispherical SPECT imager for three-dimensional brain imaging.

A completely stationary, hemispherical-coded aperture SPECT imaging system was designed to produce three-dimensional images of the brain. The system consisted of a hemispherical multiple-pinhole coded aperture and 20 small (100 x 100 mm crystal area) digital gamma cameras. Reconstructions and measured performance specifications from two laboratory versions of the imager are presented. The reconstructed field of view of these systems was an ellipsoidal region with semi-diameters of 100 x 100 x 50 mm. The reconstructed spatial resolution for a point source in air at the center of this field was found to be 4.8 mm FWHM and the corresponding system sensitivity was 36 cps/microCi. An analysis using an ideal-observer model indicated that the multiplexed projection data suffered a 21% degradation relative to similar, but nonmultiplexed SPECT data. Therefore, by this measure, the effective sensitivity of the brain imager was 79% of the measured value.

Computed tomography in the evaluation of penetrating neck trauma: a preliminary study.

HYPOTHESIS: Penetrating neck trauma has traditionally been evaluated by surgical exploration and/or invasive diagnostic studies. We hypothesized that computed tomography (CT), used as an early diagnostic tool to accurately determine trajectory, would direct or eliminate further studies or procedures in stable patients with penetrating neck trauma. DESIGN: Retrospective case series. SETTING: Academic, urban, level I trauma center. PATIENTS: Hemodynamically stable patients without hard signs of vascular injury or aerodigestive violation who had sustained penetrating trauma to the neck. INTERVENTIONS: Patients underwent a spiral CT as an initial diagnostic study after initial evaluation in the trauma bay. Further invasive studies were directed by CT findings. MAIN OUTCOME MEASURES: Number of invasive studies performed. RESULTS: Twenty-three patients were identified during the 30-month period. Nineteen patients sustained gunshot wounds; 3, shotgun wounds; and 1, a stab wound. One patient died of a cranial gunshot wound. Three isolated zone I, 1 isolated zone II, 9 isolated zone III, and 10 multiple neck zone trajectories were evaluated. Thirteen patients were identified by CT to have trajectories remote from vital structures and required no further evaluation. Ten patients underwent angiography. Only 2 underwent bronchoscopy and esophagoscopy. Four patients were discharged from the emergency department; 7 other patients were discharged within 24 hours. No adverse patient events occurred before, during, or after CT scan. CONCLUSIONS: Computed tomography in stable selected patients with penetrating neck trauma appears safe. Invasive studies can often be eliminated from the diagnostic algorithm when CT demonstrates trajectories remote from vital structures. As a result, efficient evaluation and early discharge from the trauma bay or emergency department can be realized. Further prospective study of CT scan after penetrating neck trauma is needed.

Timing of neonatal testosterone exposure in the differentiation of estrogenic regulatory systems for aggression.

Neonatal female CF-1 mice were exposed to testosterone (T) or oil vehicle on Days 1-3, 4-6, or 7-9 postpartum and were tested for the display of male-like aggressive behavior in response to diethylstilbestrol (DES) after ovariectomy during adulthood. The results showed that only the Day 1-3 T treatment established the capacity to exhibit fighting behavior following estrogen administration. These data suggest that sexual differentiation of an estrogen-responsive regulatory system for aggressive behavior occurs during a highly restricted period early in life.