In order to achieve the most accurate results, there are a few ultrasound studies that are best scheduled within a certain time frame. Namely, these studies are: sonohysterograms, studies performed for evaluation of the endometrium, nuchal translucency, and anatomy studies.
The best time to evaluate the endometrium for possible polyp, fibroid invasion, irregularity of the endometrium, or to get an accurate measurement when determining endometrial thickness, is between days 7 and 10 of the menstrual cycle. This is also very important when performing a sonohysterogram to avoid a false positive result. If your patient is spotting between periods or having abnormal bleeding, accurate evaluation of the endometrium and the timing of the evaluation are very important.
The guidelines given by the NTQR state that nuchal translucency (NT) ultrasound is to be performed between 11 weeks and 13 weeks 6 days. The objective is to balance early detection of a problem with the ability to see the baby well enough. Performing an NT ultrasound between 12 ½ and 13 ½ weeks will help allow for accurate evaluation. Sometimes, when performed earlier, it is difficult to clearly evaluate the NT due to the size of the baby.
With anatomy scans, we face the same issue. We want to detect abnormalities as early as possible, however, we also want to be able to see small structures well enough to clearly evaluate them. When we are looking at small structures such as the chambers of the heart, it is important that that we have the clearest view possible. Performing anatomy scans close to the 19-20th week rather than week 16 may help one evaluate these smaller structures.
I have been in the field of ultrasound for 25 years and I am able to advise your office on many ultrasound related subjects. Feel free to contact me for advice on how to make sure your ultrasound practice is of the highest accuracy and quality.
Denise Barbato RDMS