Intracytoplasmic sperm injection (ICSI) has become the most successful technique in male infertility treatment. For ICSI only one sperm is needed per egg retrieved, which is injected directly into the egg.
Intracytoplasmic Morphological Sperm Injection (IMSI) is similar to ICSI with the one exception: a doctor before microinjection using a multiple magnification of the microscope - about 6,000 times - carefully examines the sperm, chooses the most "healthy", without pathological changes. Only after that doctor takes a sperm for its introduction into the egg.