The effect of magnetic resonance imaging on neural tube development in an early chicken embryo model.

PURPOSE: We aimed to determine whether varying the magnetic field during magnetic resonance imaging would affect the development of chicken embryos and neural tube defects. METHODS: Following incubation for 24 h, we exposed chicken embryos to varying magnetic fields for 10 min to assess the impact on development. Three magnetic resonance imaging devices were used, and the eggs were divided into four groups: group 1 is exposed to 1 T, group 2 is exposed to 1.5 T, group 3 is exposed to 3 T, and group 4, control group, was not exposed to magnetic field. After MRI exposure, all embryos were again put inside incubator to complete 48 h. "The new technique" was used to open eggs, a stereomicroscope was used for the examination of magnified external morphology, and each embryo was examined according to the Hamburger and Hamilton chicken embryo stages. Embryos who had delayed stages of development are considered growth retarded. Growth retardation criteria do not include small for stage. RESULTS: Compared with embryos not exposed to a magnetic field, there was a statistically significant increase in the incidence of neural tube closure defects and growth retardation in the embryos exposed to magnetic fields (p < 0.05). However, although the incidence of neural tube closure defects was expected to increase as exposure (tesla level) increased, we found a higher rate of defects in the 1.5-T group compared with the 3-T group. By contrast, the highest incidence of growth retardation was in the 3-T group, which was consistent with our expectation that growth retardation would be more likely as tesla level increased. CONCLUSIONS: We therefore conclude that the use of magnetic resonance imaging as a diagnostic tool can result in midline closure defects and growth retardation in chicken embryos. We hypothesize that this may also be true for human embryos exposed to MRI. If a pregnant individual is to take an MRI scan, as for lumbar disc disease or any other any other reason, our results indicate that consideration should be given to an avoidance of MRI during pregnancy.

Olfactory functions after transsphenoidal pituitary surgery: endoscopic versus microscopic approach.

OBJECTIVES/HYPOTHESIS: Olfactory disturbances could be observed following transsphenoidal pituitary surgeries. To our knowledge, no previous comparative studies on olfactory functions after transsphenoidal endoscopic and microscopic approaches have been performed. STUDY DESIGN: Prospective study comparing olfactory functions between endoscopic and microscopic transsphenoidal pituitary surgery. METHOD: Twenty-five patients operated on with the endoscopic approach and 25 patients operated on with the microscopic transsphenoidal approach have been evaluated. The Smell Diskettes Olfaction Test was used during the preoperative period, 1 month after the operation, and 6 months after the operation. In addition, the relationship between intraoperative cerebrospinal fluid leakage from the pituitary and postoperative synechiae formation with olfaction system was evaluated. The results were analyzed using the Friedman test, Mann-Whitney test, and Chi-Square test. RESULTS: In the endoscopic group, there were two hyposmic patients and no anosmic patients. In the microscopic group, there were 13 hyposmic patients and five anosmic patients. The data was statistically different between both groups (P <0.05). Cerebrospinal fluid leakage was observed in nine patients in the endoscopic group and in 10 patients in the microscopic group. There was no statistically significant difference between cerebrospinal fluid leakage and olfactory disturbances in both groups (P >0.05). Synechia was observed in nine patients in the microscopic group and in only one patient in the endoscopic group. There was a statistically significant difference between the presence of synechia and olfactory disturbances (P <0.05). CONCLUSIONS: This is the first study to seek the difference between the endoscopic and microscopic transsphenoidal approaches on the olfactory system during pituitary surgery. The obtained results indicate that an endoscopic approach seems to be more advantageous than a microscopic approach for protecting olfactory system and function.