Ob-Gyn Coding Alert

Gestational age: The American College of Radiology (ACR) recommends that fetal MR be deferred until after 20 weeks. “This is in part because the fetus is so small at earlier gestational ages that MR is unlikely to add much additional information to ultrasound, but it is also because the effects of energy from the MR on the developing fetus are not completely understood. There is concern for the developing hearing structures in particular,” Witt says.

Ultrasound: Some centers always perform a complete fetal ultrasound prior to MRI. The advantages are:

• detecting fetal demise before MR is performed;
• determining fetal lie in advance so that the coils can be positioned more precisely, especially if only a few MR sequences are be taken;
• the anatomic issues are well understood so that the MR can be appropriately set to target the areas of interest.

For some centers, ultrasound first is not possible, and in this situation, it will be necessary to perform an ultrasound following the MR, or at least to have a report from recent ultrasonography to help verify fetal size and anatomy. “We will have to see if payers bundle the initial or subsequent fetal ultrasound on the same date of service,” Witt says.