Intracytoplasmic Morphologically-selected Sperm Injection (IMSI) was first introduced as an IVF technique in 2004. It is basically very similar to ICSI (Intracytoplasmic Sperm Injection) where a single sperm is injected into an egg, the only difference is that the sperm is selected using a very powerful microscope compared to the ICSI microscope. The image of the sperm is magnified around 6000 times during IMSI and this allows the embryologist to analyse it in greater detail and choose the healthiest-looking one for injection.
Understanding IVF Treatment
What exactly are the embryologists looking for?
In ICSI, the best looking sperm in a sample are always selected. Sperm with irregular-shaped heads, two tails, or two heads etc are avoided. But there may be some defects which aren’t very obvious with ICSI. The greater magnification afforded by IMSI enables embryologists to analyse the sperm in greater depth and so narrow down the sample of potential candidates even further. For example, sperm with vacuoles in their heads are avoided because these structures are considered detrimental for normal embryo development.
Studies have suggested that this technique may improve the pregnancy rate. However, critics argue that there is not a huge benefit since the embryologist will always try and select the best sperm for ICSI anyway. Research seems to suggest that IMSI may be most beneficial to selected infertile couples with a previous history of fertilisation failure or poor embryo developmental outcome. Long term studies are required to confirm the benefits as the procedure is very expensive and time-consuming. In some clinics in the UK, IMSI can be an additional £400-£500 in addition to the cost of ICSI. The equipment is expensive and of course the embryologist needs extra training and time to perform the technique, so this can explain some of the cost.
IVF Treatment and Techniques
Techniques like ICSI and IMSI have revolutionised IVF treatment in recent years. As long as techniques are appropriately used in a clinic, then patients will reap the rewards of advancements made in the field.