What is the Difference Between ICSI and IMSI

The main difference between ICSI and IMSI is that in ICSI, a single sperm cell is injected directly into the cytoplasm of the egg cell.t But, IMSI is an advanced version of ICSI where high-quality sperms are injected into the egg cells. Furthermore, ICSI is associated with comparatively lower pregnancy rates, while IMSI is always associated with higher pregnancy rates. 

In brief, ICSI (Intracytoplasmic sperm injection) and IMSI (Intracytoplasmic morphologically selected sperm injection) are two laboratory techniques used for in vitro fertilization (IVF) treatments. And, in both techniques, the egg fuses with the sperm outside the body. Also, both methods involve the selection of sperms under the microscope.

Key Areas Covered 

1. What is ICSI
     – Definition, Procedure, Importance
2. What is IMSI
     – Definition, Procedure, Importance
3. What are the Similarities Between ICSI and IMSI
     – Outline of Common Features
4. What is the Difference Between ICSI and IMSI
     – Comparison of Key Differences

Key Terms 

ICSI, IMSI, In Vitro Fertilization, Pregnancy Rates, Sperm Selection

What is ICSI 

ICSI (intracytoplasmic sperm injection) is a method of in vitro fertilization (IVF), requiring a single sperm cell for the injection into the cytoplasm of an egg cell directly. Besides, IVF is a technique in which the fertilization of the egg cells and sperms occurs outside the body. Although the steps followed before and after fertilization are the same in both techniques, ICSI requires a single sperm while IVF requires 50-100 thousand sperms for fertilization. Here, the higher number of sperm cell requirement is due to the occurrence of the acrosome reaction in IVF.

Figure 1: ICSI

Furthermore, sperms are selected under 200× to 400× magnification, and normal-looking spermatozoa are injected into the egg cells under 200× magnification.  

What is IMSI 

IMSI (intracytoplasmic morphologically selected sperm injection) is an advanced method of ICSI. Basically, the most significant feature of IMSI is the selection of sperms under high magnification (6,600×). Furthermore, the quality sperms are smooth, symmetric, having an oval configuration, with average length, and width limits (4.75±0.28 µm and 3.28±0.20 µm, respectively).

Figure 2: General Procedure of ICSI and IMSI

Also, they have a homogeneous nuclear chromatin mass, with no regional nuclear disorders, and containing no more than one small vacuole with a borderline diameter of 0.78±0.18 µm. Significantly, due to the high quality of sperms, IMSI always associates with high pregnancy rates. 

Similarities Between ICSI and IMSI  

• ICSI  and IMSI are two techniques of in vitro fertilization (IVF)  treatments.  
• Generally, in both techniques, the egg cell fuses with a sperm outside the body under laboratory conditions. Hence, both of them involve monitoring and stimulating a woman’s ovulatory process,  removing an egg or eggs from the woman’s ovaries and letting the sperms to fertilize them in a liquid in a laboratory.    
• After that, the fertilized egg (zygote)  undergoes embryo culture for  2–6 days; it is implanted in the uterus,  with the intention of establishing a successful pregnancy.    
• Both are techniques of assisted reproductive technology for infertility treatment and gestational surrogacy. 

Difference Between ICSI and IMSI 

Definition 

ICSI (Intracytoplasmic sperm injection) refers to an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg. Meanwhile, IMSI (Intracytoplasmic morphologically selected sperm injection) refers to a laboratory technique used for in vitro fertilization treatments in which high-quality sperms are injected into the egg for fertilization; it is an advanced version of ICSI. 

Significance 

ICSI is a method of IVF, requiring a single sperm cell for the injection directly into the cytoplasm of the egg cell, while IMSI is an advanced version of ICSI, using high-quality sperms for the injection into the egg cells. 

Sperm Selection 

ICSI requires only one sperm per egg cell, while sperm selection occurs under high magnification (6,600x) in IMSI. 

Importance 

ICSI avoids the taking place of the acrosome reaction, while as IMSI is an advanced technique associated with high pregnancy rates. 

Conclusion 

In brief, ICSI (intracytoplasmic sperm injection) is a modification of IVF where a single sperm is enough for the fertilization of an egg cell. Also, it avoids the occurrence of the acrosome reaction as in traditional IVF. Meanwhile, IMSI (intracytoplasmic morphologically selected sperm injection) is an advanced method of ICSI where the sperm selection occurs for the fertilization under high magnification. Therefore, it always associates with high pregnancy rates as the process uses high-quality sperms. Hence, the main difference between ICSI and IMSI is the method of sperm selection and pregnancy rates. 

References:

1. Kim, Hyung Jun et al. “Comparison between intracytoplasmic sperm injection and intracytoplasmic morphologically selected sperm injection in oligo-astheno-teratozoospermia patients.” Clinical and experimental reproductive medicine vol. 41,1 (2014): 9-14. doi:10.5653/cerm.2014.41.1.9.

Image Courtesy:

1. “Icsi” (Public Domain) via Commons Wikimedia   
2. “Blausen 0060 AssistedReproductiveTechnology” By BruceBlaus. “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia