1. Imaging the pregnant patient with right lower quadrant pain
Julia R. Fielding, M.D.
RSNA 2010

2. Ultrasound is test of choice
First trimester
With bleeding
exclude ectopic pregnancy
renal stones
-Without bleeding
ovarian pathology

3. Ectopic Pregnancy No IUP and positive pregnancy test
1/3 of those with ectopic pregnancy will have a normal US exam
Those with a simple adnexal cyst have a 10% likelihood of ectopic pregnancy
A complex non-ovarian mass has a sensitivity of 84%, specificity 99% and positive predictive value of 96% for ectopic pregnancy
Complex fluid/blood is often present
Dighe M et al, J Clin Ultrasound 2008;36:

4. ECTOPIC PREGNANCY
Courtesy Dr. D. Brown, Mayo Clinic

5. Renal stones Incidence of 1/1500 pregnancies
Stones that are >5mm, located in the proximal ureter and of irregular shape usually will require treatment
US will identify hydronephrosis
Ureteral jets indicate an incompletely obstructed ureter and may spare the patient a stent

6. HYDRONEPHROSIS
BLADDER STONE

7. Right mid ureteral stone
SCOUT
10 MINUTE

8. Differential diagnosis ovarian pathology
Corpus luteum cyst
Usually 2-5cm, can be up to 10cm in size
Regresses week as placenta develops
Simple cyst/hemorrhagic cyst/endometrioma/dermoid
Torsion – 70% cases with abnormal adnexa
Cancer very rare

9. Simple Cyst
Courtesy Dr. D. Brown, Mayo Clinic

10. Ovarian torsion

12. Use of CT increasing
N Engl J Med 2007;357:

13. What are the numbers?
62 million CT scans annually, 4 million in children
University of North Carolina ER data:
, pediatric admissions increased 2%, chest CT increased by 435%, abdominal CT by 49% (Emerg Radiol 2007;14:227-32)
Brown University, Rhode Island Hospital data:
Number of pregnant women scanned increased 89% in 10 years with only a 7% increase in admissions (RSNA 2007)

14. Why do we worry?
In general, fetal absorption is 40% that of maternal abdomen
Ex: Maternal pelvic CT dose is 4cSv, fetal dose is cSv (1cSv =1 rem)
This is well below the 10cSv level for teratogenic effects
However….
Invest Radiol 2000;35:

15. Why do we worry?
Young children (and presumably those in utero) are most susceptible to radiation damage and therefore at higher risk for development of cancers later in life
Organs involved are brain, digestive tract, bone marrow (leukemia)

16. N Engl J Med 2007;357:

17. N Engl J Med 2007;357:

18. What can we do? Have a plan!
1.Balance risks/benefits – talk over the procedure with the referring physician and make sure CT is needed and is the test of choice.
2. Let the referring physician discuss and document the need for the CT scan in the medical record

19. What can we do?
3.Get written and oral informed consent for use of radiation (see new ACR guidelines)
4.Avoid multiple CT scans – radiation effects are cumulative
5.Use best scanning techniques – automatic dose reduction is useful, beware dropping the maS so low that the scan is not diagnostic

20. What are the indications for CT scan in pregnancy?
1. Renal stones when US is indeterminate particularly in 2nd/3rd trimester
2. Appendicitis – MR is now test of choice, CT appropriate for IBD, obstruction
3. Cancer staging – substitute MR if possible
4. Lung disease – PE studies and V/Q scans yield similar radiation doses
5. Trauma – use your routine protocol, most common cause of fetal death is maternal death
6. Intracranial hemorrhage

21. What is the radiation dose to the fetus?
For CT examination of head, extremities and chest, minimal <10 mSv
For CT of the abdomen/pelvis, moderate cSv

22. Is there a risk to the use of IV contrast agent?
Very minimal risk of depression of fetal thyroid function by free iodide
Water-soluble contrast agents (100cc) contain 5 micrograms of free iodide, less than 1/10th the level known to cause thyroid dysfunction in neonates
Exception would be maternal renal failure when free iodide not excreted back across placenta
Eur Radiol 2005;15:
Radiology 2010;256:

23. Flank pain/obstructing ureteral stone
Choice 1: Ultrasound with hydronephrosis, severe pain, stent placed prophylactically under ultrasound guidance
Choice 2: <24 weeks, limited IVU
Choice 3: >24 weeks, helical CT

24. HYDRONEPHROSIS
SINGLE LEFT JET

25. RIGHT HYDRONEPHROSIS

26. DIILATED URETER

27. COMPRESSED URETER

28. Lower abdominal pain with suspicion of appendicitis
Ultrasound, followed by
Choice 1: MRI of the abdomen and pelvis
Choice 2: Contrast-enhanced helical CT

29. 27 year old woman, 33 weeks pregnant with negative ultrasound
Noemi garcia
Courtesy Dr. E. Lazarus, Rhode Island Hospital

30. Ultrasound demonstrated echogenic material around the proximal appendix which was thought to represent possible air in phlegmon from rupture, but the CT demonstrated that the appendix was enveloped by cecum

31. 27 years old, 22 weeks pregnant

32. Cancer staging of the abdomen and pelvis
Choice 1: MRI of the abdomen and pelvis, judicious use of Gd-DTPA
Choice 2: Contrast-enhanced CT of the abdomen/pelvis

33. Jejunal adenoCA with SBO
I+ CT

35. Recurrent gastric cancer

37. TRAUMA Use your routine protocol
Intravenous contrast agent always necessary, oral contrast agent varies by institution

38. Ruptured splenic artery aneurysm

40. When do we use MRI in pregnancy?
1. The information requested from the MR study cannot be acquired using US
2. The data are needed to affect the care of the patient or fetus during the pregnancy
3. The referring physician does not feel is is prudent to wait until the patient is no longer pregnant to obtain these data.

41. When do we use MRI during pregnancy?
In general, when the information to be obtained is absolutely essential to the well being of the mother or child
Specifically,
RLQ pain, suspicion of appendicitis/bowel disease
Characterization of an adnexal mass
Cancer staging
Choledocholithiasis
Head and back injuries
Fetal/placental abnormalities

42. Safety issues
Present data have not conclusively documented any deleterious effects of MR imaging exposure on the developing fetus
All pregnant women should understand and sign a consent for the performance of MRI

43. What about Gd chelates and fetal renal development?
Gd chelates do pass through the placenta and remain in the amniotic fluid
Because of our lack of knowledge regarding contrast/fetal kidneys, avoid Gd chelates in pregnant women unless absolutely necessary - cancer staging/vascular issues such as aneurysm, AVM

44. Basic protocol for maternal abd/pelvis
Sagittal/axial/coronal ultrafast T2 weighted images (HASTE/SSFSE) using large FOV and torso coil if possible. Axial T2W series performed with fat saturation.
Ax T1 weighted image with fat sat through pelvis (to locate blood)
Patient supine or in left lateral decubitus position

45. Appendicitis Incidence 1:1500 pregnancies
Graded compression US is impractical after the first trimester
MRI is test of choice – excellent NPV for appendicitis in those patients with a normal US (94%)
Alternative is CT (fetal dose 1.8cGy)
Appearance on T2WI: Tube >6mm, often vertical, just below TI with adjacent high signal edema

46. Case 1

49. Case 2

51. TERMINAL ILEUM

52. APPENDIX

53. Case 3 Acute appendicitis with perforation
Low signal appendicolith adjacent to appendix

56. Bowel inflammation/obstruction
Incidence SBO in pregnancy is 1 in 1500 to 1 in 66,500.
Majority due to adhesions, volvulus, internal hernias and inflammatory bowel disease
MRI has a 95% sensitivity for obstruction, while location of transition point can be identified in 70-90%

57. Small bowel adhesions Third trimester pregnancy
s/p total colectomy for UC with formation of J pouch
Small bowel obstruction to right of uterus

58. POINT OF TRANSITION

60. Uterine leiomyomata
Leiomyoma is the most common adnexal mass with an prevalence of 40%
These masses grow during pregnancy
May torse, bleed or interfere with fetal development or delivery (LUS fibroid)
Bridging vessels from the uterus and/or continuirity of the serosa are diagnostic of a fibroid

61. Uterine leiomyomata Round, well-demarcated
Variable T2 signal intensity
High T1 signal intensity indicated bleeding, “red degeneration”

62. Fibroid in patient with lupus

63. First trimester pregnancy

64. Pancreatitis
Pregnant female, 2nd trimester with abdominal pain and elevated amylase
Diagnosis – pancreatitis
Are there stones involved?

65. YES!

66. T2-weighted/fat sat images - PANCREATITIS

67. CHOLEDOCHOLITHIASIS

68. Renal mass identified on US

69. Placenta previa

70. Does this work with AIP? Usually not
Percreta may sometimes be identified if there is extension of placenta into bladder or when the placenta is posterior
Accreta and increta can rarely be identified

71. References
Pedrosa I, et al. Magnetic resonance imaging of right lower quadrant pain in pregnant and non-pregnant patients. Radiographics 2007; 27:
Fielding JR, et al. Magnetic resonance imaging of abdominal pain during pregnancy. Top Magn Reson Imaging 2006;17:

72. References
Wieseler KM, Imaging in pregnant patients: Examination appropriateness. Radiographics 2010; 30:

73. Thank you