Multiple Gestations

Variant: 1 Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.

Procedure	Appropriateness Category	Relative Radiation Level
US pregnant uterus transabdominal	Usually Appropriate	O
US pregnant uterus transvaginal	Usually Appropriate	O
US assessment for TTTS	Usually Not Appropriate	O
US cervix transvaginal	Usually Not Appropriate	O
US duplex Doppler fetal middle cerebral artery	Usually Not Appropriate	O
US duplex Doppler fetal umbilical artery	Usually Not Appropriate	O
US echocardiography fetal	Usually Not Appropriate	O
US pregnant uterus biophysical profile	Usually Not Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O
MRI fetal without IV contrast	Usually Not Appropriate	O

Variant: 2 Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.

Procedure	Appropriateness Category	Relative Radiation Level
US pregnant uterus transabdominal	Usually Appropriate	O
US pregnant uterus transvaginal	Usually Appropriate	O
US cervix transvaginal	May Be Appropriate	O
US echocardiography fetal	May Be Appropriate	O
US assessment for TTTS	Usually Not Appropriate	O
US duplex Doppler fetal middle cerebral artery	Usually Not Appropriate	O
US duplex Doppler fetal umbilical artery	Usually Not Appropriate	O
US pregnant uterus biophysical profile	Usually Not Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O
MRI fetal without IV contrast	Usually Not Appropriate	O

Variant: 3 Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.

Procedure	Appropriateness Category	Relative Radiation Level
US cervix transvaginal	Usually Appropriate	O
US echocardiography fetal	Usually Appropriate	O
US pregnant uterus transabdominal	Usually Appropriate	O
US duplex Doppler fetal umbilical artery	May Be Appropriate	O
US pregnant uterus transvaginal	May Be Appropriate	O
US assessment for TTTS	Usually Not Appropriate	O
US duplex Doppler fetal middle cerebral artery	Usually Not Appropriate	O
US pregnant uterus biophysical profile	Usually Not Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O
MRI fetal without IV contrast	Usually Not Appropriate	O

Variant: 4 Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.

Procedure	Appropriateness Category	Relative Radiation Level
US assessment for TTTS	Usually Appropriate	O
US cervix transvaginal	Usually Appropriate	O
US duplex Doppler fetal umbilical artery	Usually Appropriate	O
US echocardiography fetal	Usually Appropriate	O
US pregnant uterus transabdominal	Usually Appropriate	O
US duplex Doppler fetal middle cerebral artery	May Be Appropriate	O
US pregnant uterus transvaginal	May Be Appropriate	O
MRI fetal without IV contrast	May Be Appropriate	O
US pregnant uterus biophysical profile	Usually Not Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O

Variant: 5 Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.

Procedure	Appropriateness Category	Relative Radiation Level
US pregnant uterus transabdominal	Usually Appropriate	O
US cervix transvaginal	May Be Appropriate	O
US duplex Doppler fetal middle cerebral artery	May Be Appropriate	O
US duplex Doppler fetal umbilical artery	May Be Appropriate	O
US echocardiography fetal	May Be Appropriate	O
US pregnant uterus biophysical profile	May Be Appropriate	O
US pregnant uterus transvaginal	May Be Appropriate	O
US assessment for TTTS	Usually Not Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O
MRI fetal without IV contrast	Usually Not Appropriate	O

Variant: 6 Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.

Procedure	Appropriateness Category	Relative Radiation Level
US assessment for TTTS	Usually Appropriate	O
US duplex Doppler fetal middle cerebral artery	Usually Appropriate	O
US duplex Doppler fetal umbilical artery	Usually Appropriate	O
US pregnant uterus transabdominal	Usually Appropriate	O
US cervix transvaginal	May Be Appropriate	O
US echocardiography fetal	May Be Appropriate	O
US pregnant uterus biophysical profile	May Be Appropriate	O
US pregnant uterus transvaginal	May Be Appropriate	O
MRI fetal without IV contrast	May Be Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O

Variant: 7 Multiple gestations. Dichorionic or multichorionic higher order multiples or monochorionic gestations. Known abnormality or discordance between fetuses (fluid, size, weight). Growth and antepartum surveillance.

Procedure	Appropriateness Category	Relative Radiation Level
US duplex Doppler fetal middle cerebral artery	Usually Appropriate	O
US duplex Doppler fetal umbilical artery	Usually Appropriate	O
US pregnant uterus biophysical profile	Usually Appropriate	O
US pregnant uterus transabdominal	Usually Appropriate	O
US assessment for TTTS	May Be Appropriate	O
US cervix transvaginal	May Be Appropriate	O
US echocardiography fetal	May Be Appropriate	O
US pregnant uterus transvaginal	May Be Appropriate	O
MRI fetal without IV contrast	May Be Appropriate	O
MRI fetal without and with IV contrast	Usually Not Appropriate	O

Panel Members

Summary of Literature Review

Introduction/Background

Special Imaging Considerations

Initial Imaging Definition

Discussion of Procedures by Variant

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
A. MRI Fetal Without and With IV Contrast

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
B. MRI Fetal Without IV Contrast

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
C. US Assessment for TTTS

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
D. US Cervix Transvaginal

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
E. US Duplex Doppler Fetal Middle Cerebral Artery

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
F. US Duplex Doppler Fetal Umbilical Artery

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
G. US Echocardiography Fetal

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
H. US Pregnant Uterus Biophysical Profile

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
I. US Pregnant Uterus Transabdominal

Variant 1: Known or suspected multiple gestations. Monochorionic or dichorionic. First trimester. Initial imaging.
J. US Pregnant Uterus Transvaginal

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
A. MRI Fetal Without and With IV Contrast

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
B. MRI Fetal Without IV Contrast

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
C. US Assessment for TTTS

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
D. US Cervix Transvaginal

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
E. US Duplex Doppler Fetal Middle Cerebral Artery

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
F. US Duplex Doppler Fetal Umbilical Artery

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
G. US Echocardiography Fetal

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
H. US Pregnant Uterus Biophysical Profile

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
I. US Pregnant Uterus Transabdominal

Variant 2: Multiple gestations. Monochorionic or dichorionic. First trimester. First trimester ultrasound performed. Next imaging study.
J. US Pregnant Uterus Transvaginal

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
A. MRI Fetal Without and With IV Contrast

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
B. MRI Fetal Without IV Contrast

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
C. US Assessment for TTTS

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
D. US Cervix Transvaginal

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
E. US Duplex Doppler Fetal Middle Cerebral Artery

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
F. US Duplex Doppler Fetal Umbilical Artery

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
G. US Echocardiography Fetal

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
H. US Pregnant Uterus Biophysical Profile

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
I. US Pregnant Uterus Transabdominal

Variant 3: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Second trimester anatomy examination. Follow-up imaging.
J. US Pregnant Uterus Transvaginal

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
A. MRI Fetal Without and With IV Contrast

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
B. MRI Fetal Without IV Contrast

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
C. US Assessment for TTTS

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
D. US Cervix Transvaginal

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
E. US Duplex Doppler Fetal Middle Cerebral Artery

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
F. US Duplex Doppler Fetal Umbilical Artery

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
G. US Echocardiography Fetal

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
H. US Pregnant Uterus Biophysical Profile

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
I. US Pregnant Uterus Transabdominal

Variant 4: Multiple gestations. Monochorionic twins. Second trimester anatomy examination. Follow-up imaging.
J. US Pregnant Uterus Transvaginal

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
A. MRI Fetal Without and With IV Contrast

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
B. MRI Fetal Without IV Contrast

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
C. US Assessment for TTTS

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
D. US Cervix Transvaginal

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
E. US Duplex Doppler Fetal Middle Cerebral Artery

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
F. US Duplex Doppler Fetal Umbilical Artery

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
G. US Echocardiography Fetal

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
H. US Pregnant Uterus Biophysical Profile

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
I. US Pregnant Uterus Transabdominal

Variant 5: Multiple gestations. Dichorionic twins or multichorionic higher order multiples. Growth and antepartum surveillance.
J. US Pregnant Uterus Transvaginal

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
A. MRI Fetal Without and With IV Contrast

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
B. MRI Fetal Without IV Contrast

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
C. US Assessment for TTTS

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
D. US Cervix Transvaginal

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
E. US Duplex Doppler Fetal Middle Cerebral Artery

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
F. US Duplex Doppler Fetal Umbilical Artery

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
G. US Echocardiography Fetal

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
H. US Pregnant Uterus Biophysical Profile

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
I. US Pregnant Uterus Transabdominal

Variant 6: Multiple gestations. Monochorionic twins. Growth and antepartum surveillance.
J. US Pregnant Uterus Transvaginal

Variant 7: Multiple gestations. Dichorionic or multichorionic higher order multiples or monochorionic gestations. Known abnormality or discordance between fetuses (fluid, size, weight). Growth and antepartum surveillance.

Summary of Recommendations

Supporting Documents

The evidence table, literature search, and appendix for this topic are available at https://acsearch.acr.org/list. The appendix includes the strength of evidence assessment and the final rating round tabulations for each recommendation.

For additional information on the Appropriateness Criteria methodology and other supporting documents, please go to the ACR website at https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Appropriateness-Criteria.

Safety Considerations in Pregnant Patients

Appropriateness Category Names and Definitions

Appropriateness Category Name	Appropriateness Rating	Appropriateness Category Definition
Usually Appropriate	7, 8, or 9	The imaging procedure or treatment is indicated in the specified clinical scenarios at a favorable risk-benefit ratio for patients.
May Be Appropriate	4, 5, or 6	The imaging procedure or treatment may be indicated in the specified clinical scenarios as an alternative to imaging procedures or treatments with a more favorable risk-benefit ratio, or the risk-benefit ratio for patients is equivocal.
May Be Appropriate (Disagreement)	5	The individual ratings are too dispersed from the panel median. The different label provides transparency regarding the panel’s recommendation. “May be appropriate” is the rating category and a rating of 5 is assigned.
Usually Not Appropriate	1, 2, or 3	The imaging procedure or treatment is unlikely to be indicated in the specified clinical scenarios, or the risk-benefit ratio for patients is likely to be unfavorable.

Relative Radiation Level Information

Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level (RRL) indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, because of both organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for pediatric examinations are lower as compared with those specified for adults (see Table below). Additional information regarding radiation dose assessment for imaging examinations can be found in the ACR Appropriateness Criteria^® Radiation Dose Assessment Introduction document.

Relative Radiation Level Designations
Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
☢	<0.1 mSv	<0.03 mSv
☢☢	0.1-1 mSv	0.03-0.3 mSv
☢☢☢	1-10 mSv	0.3-3 mSv
☢☢☢☢	10-30 mSv	3-10 mSv
☢☢☢☢☢	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as “Varies.”

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Disclaimer

The ACR Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient’s clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient’s condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the FDA have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination