A pelvic ultrasound will detect any type of fibroid you may have, below is the different types of fibroids you could have;
Intramural fibroids - fibroids that are within the muscle of the wall of the uterus. Small fibroids are often asymptomatic and do not need treatment. If there are several fibroids, or they become very large, or are causing heavy menstrual bleeding (HMB) they may require treatment.
Subserosal fibroids - fibroids that are on the outside of the uterus, and very rarely cause a problem unless they are very large and press on other organs.
Submucosal fibroids - fibroids that grow inside the cavity of the uterus and most commonly cause heavy bleeding. These can often be easily removed with a Hysteroscopy.