More articles from Adult Brain
- Prevalence of Asymptomatic Middle Cranial Fossa Floor Pits and Encephaloceles on MR Imaging
A retrospective review was completed of high-resolution axial T2WI for internal auditory canal protocol imaging. The presence and laterality of middle cranial fossa pits (small bony defects containing CSF) and encephaloceles (brain parenchyma protrusion through osseous defects with or without bony remodeling) were recorded. A total of 203 patients were included in the final cohort; 106 (52.2%) were women. Forty-five (22.2%) patients had middle cranial fossa pits: 14 (31.1%) unilateral on the right, 17 (37.8%) unilateral on the left, and 14 (31.1%) bilateral. Ten (5.0%) patients had one or more encephaloceles, none of whom had a documented history of seizure in the electronic medical record. The incidence of such findings should be taken into account when identifying or treating such lesions as possible epileptogenic foci.
- Prolonged Microgravity Affects Human Brain Structure and Function
Brain MR imaging scans of National Aeronautics and Space Administration astronauts were retrospectively analyzed to quantify pre- to postflight changes in brain structure. Local structural changes were assessed using the Jacobian determinant. Structural changes were compared with clinical findings and cognitive and motor function. Long-duration spaceflights aboard the International Space Station, but not short-duration Space Shuttle flights, resulted in a significant increase in the percentage of total ventricular volume change (10.7% versus 0%). The percentage of total ventricular volume change was significantly associated with mission duration but negatively associated with age. Pre- to postflight structural changes of the left caudate correlated significantly with poor postural control, and the right primary motor area/midcingulate correlated significantly with a complex motor task completion time. These findings suggest that brain structural changes are associated with changes in cognitive and motor test scores and with the development of spaceflight-associated neuro-optic syndrome.
- Evaluation of Lower-Dose Spiral Head CT for Detection of Intracranial Findings Causing Neurologic Deficits
Projection data from 83 patients undergoing unenhanced spiral head CT for suspected neurologic deficits were collected. A routine dose was obtained using 250 effective mAs and iterative reconstruction. Lower-dose configurations were reconstructed (25-effective mAs iterative reconstruction, 50-effective mAs filtered back-projection and iterative reconstruction, 100-effective mAs filtered back-projection and iterative reconstruction, 200-effective mAs filtered back-projection). Three neuroradiologists circled findings, indicating diagnosis, confidence, and image quality. The routine-dose jackknife alternative free-response receiver operating characteristic figure of merit was 0.87. Noninferiority was shown for 100-effective mAs iterative reconstruction and 200-effective mAs filtered back-projection, but not for100-effective mAs filtered back-projection. The authors conclude that substantial opportunity exists for dose reduction using spiral nonenhanced head CT and that the dose level might potentially be reduced to 40% of routine dose levels or a volume CT dose index of approximately 15mGy if slight decreases in performance are acceptable. The beneficial effect of iterative reconstrution was most pronounced at this 15-mGy dose level.