INTRACYTOPLASMIC MORPHOLOGYCALLY SELECTED SPERM INJECTION – In vitro fertilization, the zona pellucida prevent entry of abnormal sperm, so the normal sperm can enter and fertilized the oocyte. Since ICSI bypass the natural sperm selection process, there is an increased risk of genetic abnormalities being transmitted to the offspring. Hence, several sperm selection method had been developed to select the most normal spermatozoa, prominent, which is the intracytoplasmic morphologically selected sperm injection technique.
The ICSI is normally performed at 200 – 400 x magnification which allow visualization of major sperm morphological defect, such as head abnormalities (round, tapering, etc.), midpiece defect (bent neck and thick midpiece), tale defect (short stubby and double) whereas minor morphological defects, such as vacuole in the sperm head, which play a scientific role in ICSI outcome, cannot be visualized.
The IMSI technique, is the new modified version of ICSI where in the sperm are magnified to about 6600 times and subjected to MOSMP criteria ( motile sperm organelle morphology examination) allowing us to select the most morphologically normal spermatozoa just prior to performing the ICSI. The IMSI system consist of an inverted light microscope attached with high power nomarski optics enhanced by digital imaging to achieve a magnification of 6600x using IMSI, the sperm is analyzed for integrity thereby allowing sperm selection and injection of normal sperm head free of vacuoles.