Preparation before ultrasonography

Ultrasonography (USG) is painless, fast and easy way to diagnose a number of diseases. Now a days, it is quite common test available in most part of Bangladesh. Ultrasound machine uses reflected sound wave to produce image of an organ or structure inside the body.
Some ultrasound exams like arm, shoulder, wrist, hand, leg, knee, foot, chest, thyroid (non biopsy), testes (scrotal) or penis can be done readily at anytime and does not require any preparation. However, some require special preparation. It is important that you follow the preparation guidelines so the sonographer can obtain the best possible images.
If you are advised to do an abdominal or combined abdomen and pelvic USG, you need to take special preparation. You should stop eating and drinking four to six hours before your scan, but oral medications can be taken with a small amount of water. If you are diabetic, you may have one piece of dry toast and one glass of juice before a morning exam — if your scan is in the afternoon then you may have a light, low- or no-fat diet.
If your doctor orders only pelvic USG (pelvis is the area below hip), you must have a full bladder before the test to see pelvic organ properly. You should cease drinking and voiding for two hours before your scan, but oral medications can be taken with a small amount of water.  If you are post-menopausal and do not have periods, your exam can be done at any time. If you are pre-menopausal (having periods) or are post-menopausal on sequential hormone replacement (you have regular period-like bleeding), your exam should be done between day 6 and day 10 of your menstrual cycle.
If you are pregnant and advised to do USG for pregnancy profile, you also need preparation. In early pregnancy, ultrasound is used to determine fetal age and viability. In the second and third trimesters, ultrasound is used to evaluate the fetus, monitor fetal growth and position, check amniotic fluid, survey the placental location etc. In this condition, there are no dietary restrictions, but you should cease voiding for one hour before your scan.
If you have any concern with your thyroid glad (Adams Apple) and your doctor orders a thyroid biopsy ultrasound, you should cease eating and drinking four to six hours before your scan is performed by scanning and identifying an area of concern in the thyroid gland requiring tissue sampling for histological diagnosis. If you are taking Aspirin or any blood thinners during the period, you should stop five to seven days prior to your appointment.

The writer is a Member of American College of Radiology. He works at Bangladesh Japan Institute of Radiology & Imaging, Dhaka.
E-mail: shan31st@gmail.com