What is IMSI?
IMSI stands for intracytoplasmic morphologically selected sperm injection. IMSI is an advanced IVF technology developed to improve pregnancy outcome in severe low sperm quality. Usually, the conventional ICSI technique is used to choose sperm for fertilization in the male factor infertility problems,
However, conventional ICSI is not effective in all cases because the magnification is still too low to see the sperm in clearer detail. What happens if we choose the wrong sperm under low magnification? The answer is the pregnancy success will be low and the miscarriage rate will be higher. We still have room for improving the chances of success by choosing the best sperm using a higher magnification than that of conventional microscopy.
The beginning of IMSI
Professor Benjamin Bartoov has developed a technique to see the sperm in much greater detail, which is called IMSI. While conventional ICSI can magnify sperm by 400–600 times, IMSI magnifies it by at least 6000 times and can increase this to more than 10000 times when combined with the digital system on the monitor screen. The sperm that looks normal at 400 times may be abnormal and not good enough for choosing when seen at a magnification of 6000 times or more, which explains why ICSI with low magnification does not achieve such good success.
However, most cases involve many factors that impact on success and the sperm is one of the most important of these, especially in the case of very low-quality sperm.
The Leica microsystem is the outstanding IMSI system that provides superb image quality for best analysis. Dr. Suchada had the opportunity to attend an IMSI workshop run by Professor Benjamin Bartoov and to be trained in using the Leica DMI6000 B by Dr. Christiane Wittemer and Bruno Laborde at Strasbourg University, France, where is the authorized training center of Leica company for the Leica microsystem. Furthermore, IMSI research is the graduation topic of Dr. Suchada from Clinical Embryology and Andrology at Jones Institute, EVMS, US. We have had great experience in using the IMSI technique since 2009.
The high magnification selection of sperm under the IMSI system might help to improve pregnancy outcome, especially in cases where conventional ICSI cannot work successfully. The sperm head contains sperm DNA that is the pivotal part of creating normal human life. Nuclear vacuole is a sperm DNA defect, which looks like a hole in the sperm head area. It is difficult to be identified under low magnification, which is why the IMSI system can improve pregnancy rates, especially for those who have a high nuclear vacuole rate.
Do sperm defects impact on the quality of embryos?
It is not always the case that sperm defects will result in bad embryo quality but they may not be implanted successfully or might result in miscarriage. It is
obvious that the sperm factor is one of the most difficult infertility factors to resolve in some cases. Defective sperm can have good fertilization rates and produce good quality embryos but have a poor pregnancy outcome. Usually in the case of poor sperm quality, the fertilization rates and implantation rates are low. Because of this, in some cases that have multiple IVF failure even if we have a perfect embryo for transfer, we must think about sperm defects and try to find the best solution for them.
What is the ideal sperm for selection?
The criteria of good sperm are normal oval nuclear shape and without a large vacuole. In cases where we cannot find ideal sperm, we still need to find the second class of sperm, which have less sperm defects and still have the potential for pregnancy outcome. The second class of sperm are oval and of a narrow shape without a large nuclear vacuole.
How does IMSI work to improve pregnancy outcome?
IMSI is an advanced technology extends the process of conventional ICSI. The procedure is time-consuming and needs a skillful person who is well trained in sperm selection under high magnification. Due to the clearer detail of sperm seen in the IMSI setting, sperm selection is done correctly, which is the most a promising way to improve pregnancy outcome in cases of sperm defect that cannot be identified with conventional ICSI.