IMSI; Intracytoplasmic morphologically selected sperm injection observes the sperm by ultrahigh magnification, selecting healthy looking sperm and using it for micro-insemination (ICSI). In normal ICSI, we select sperm to be injected into oocytes by 400× magnification, but in IMSI it is magnified 6000× and a detailed sperm form (empty cells of the sperm head, tail and mid-section abnormalities) can be confirmed.
Because the sperm head is packed with genetic information and enzymes necessary for fertilization, with IMSI it is expected that the fertilization rate and pregnancy rate will be improved by using healthy looking sperm with no empty cells in the head.
It is used in cases when ICSI is performed several times and when sperm morphology is not good.
Although the validity of this method has not been established, firm evidence at the present time, it is said that abortion rate decreases, it is useful for malformation spermatosis, and so on. However, there are also reports that the results do not change with regular ICSI.
There is no invasive damage to the sperm by this method, but because it does take time to select the sperm there is concern about harmful effects (decrease of sperm motility rate and motility). Additionally, when morphologically good sperm is not obtained, there is a possibility to do ICSI with malformed sperm.