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Abstract Background Meningioma in the parasellar region may lead to visual impairment, so intraoperative neurological monitoring is essential for enucleation surgery. However, intraoperative neurological monitoring in pregnant women is challenging, as the anesthesia management must consider the effects and risks to the fetus. Remimazolam is a newly introduced intravenous anesthetic that has little effect on blood pressure. However, the effects of remimazolam on intraoperative neuromonitoring are little known. We treated a pregnant patient with parasellar meningioma who developed visual impairment, using remimazolam for anesthesia and intraoperative neurophysiological monitoring of the visual evoked potential. Case presentation A 34-year-old woman who was 20 weeks pregnant presented with visual acuity disturbances. Neuroimaging demonstrated a parasellar meningioma, and rapid tumor growth and worsening of symptoms subsequently occurred. Craniotomy for tumor removal was performed under anesthesia with remimazolam, which allowed monitoring of the visual evoked potentials. Her visual acuity was restored postoperatively, and no adverse events occurred in the fetus. Conclusion Our experience with intraoperative neuromonitoring of a pregnant woman in the third trimester showed that anesthesia with remimazolam allows safe brain surgery combined with intraoperative visual evoked potential monitoring. Further research is needed to determine the effects of remimazolam on the fetus, as well as the safe dosage and duration of exposure.

Although the standard method to evaluate skeletal muscle protein synthesis (MPS) is muscle biopsy, the method is invasive and problematic for multisite use. We conducted a small pilot study in volunteers to investigate changes in MPS according to skeletal muscle site using a noninvasive method in which 6 healthy young men were given yogurt (containing 20 g milk protein) or water, and 1 h later, l-[11C]methionine ([11C]Met) was administered intravenously. Dynamic PET/CT imaging of their thighs was performed for 60 min. The influx constant Ki of [11C]Met in skeletal muscle protein was calculated as an index of MPS using a Patlak plot, and found to be 0.6%-28% higher after ingesting yogurt than after water in 5 of the 6 volunteer participants, but it was 34% lower in the remaining participant. Overall, this indicated no significant increase in Ki after ingesting milk protein. However, when the quadriceps and hamstring muscles were analyzed separately, we found a significant difference in Ki. This demonstrates the potential of visualizing MPS by calculating the Ki for each voxel and reconstructing it as an image, which presents unique advantages of [11C]Met PET/CT for evaluating MPS, such as site-specificity and visualization.