Pelvic Pain: Positive Pregnancy Test - SD

Disclosures and Learning Objectives

I have no financial relationships to disclose.

My learning objectives today are to review features of ectopic pregnancy and I'll be focusing on some of the more uncommon types including cesarean scar and interstitial ectopic pregnancy.

I'll also discuss the physiologic changes and common etiologies for pelvic pain in the pregnant patient.

And I'll list our sonographic approach for evaluating the pregnant patient who has pelvic pain.

Review of Ectopic Pregnancy

A brief review of ectopic pregnancy is what I wanna discuss.

First, everyone knows that this occurs when a blastocyst implants outside the uterine cavity.

Most commonly the blastocysts will implant in different portions of the fallopian tube as listed here, the ampullary fibular or isthmic part of the tube.

And much less common the blastocysts will implant in the interstitial part of the tube at the cesarean scar in the cervix, the ovary or the peritoneal cavity.

Classic Tubal Ectopic Pregnancy

This is a classic tubal ectopic pregnancy.

A radiologist will have no trouble making the diagnosis.

There's no IUP and there's an adnexal mass containing a yolk sac completely separate from the ovary.

Here's a cine clip and if you follow the fallopian tube along, you'll see the ectopic pregnancy and I bet that's in the ampullary part of the fallopian tube.

Ectopic Pregnancy Facts

A few more ectopic pregnancy facts.

Ectopic pregnancy is not that common.

It is about 2% of all pregnancies, but the true incidence is likely higher.

Most important to know is that ectopic pregnancy is the leading cause of death in the first trimester, up to nine to 14% mortality from rupture of the pregnancy.

It is the onus of the radiologist to make the diagnosis as 50% of patients are asymptomatic and up to 50% of patients will have no risk factors.

Risk Factors for Ectopic Pregnancy

But the risk factors for ectopic pregnancy include a prior ectopic pregnancy, having a history of PID or gynecologic surgery, in vitro fertilization, smoking, congenital uterine anomalies and endometriosis.

Presentation of Ectopic Pregnancy

The majority of ectopic pregnancy does not present as that tubal ring as I showed in that first image.

Rather, there have been studies that have shown this.

One retrospective study that I listed below showed that 54% of ectopic pregnancy presented as a non-specific adnexal mass separate from the ovary.

Role of Beta HCG

And what about the role of beta HCG?

The most important thing for everyone to know is that there is no lower level value cutoff that will exclude ectopic pregnancy.

So you can have a beta of 10 and still have a significant rupture ectopic.

Echogenic Free Fluid in Pelvis

So you get this case to read and the technologist shows you there's no IUP in the uterus and then you see this complex fluid in the pelvis.

So what does that mean? And the patient is pregnant.

Well, the echogenic free fluid does suggest hemoperitoneum associated with an ectopic pregnancy.

And there were many reports in the literature stating a high specificity for this finding.

But then there were subsequent studies that showed that this echogenic free fluid is not specific for hemoperitoneum from a ruptured or leaking ectopic.

This particular patient did have an ectopic pregnancy.

Case Examples of Pelvic Pain in Pregnancy

So I'm gonna show a case this is a pregnant patient who came in with acute onset of pelvic pain.

What do we do? First?

We always start with the transabdominal survey.

We wanna be able to get an overview of what's going on in the pelvis.

Is there a hemoperitoneum? Are there masses in the pelvis?

And if we see abnormalities, we wanna survey up higher in the abdomen.

So these three images show very amorphous and complex looking material within the pelvis that are kind of outlining the bowel loops.

It's very difficult to delineate any clear anatomy within the pelvis.

Here's a transverse image of the uterus.

There is no IUP visible and we look up in Morrison's pouch and there's a large amount of fluid there.

So we know that this patient has a lot of hemoperitoneum.

This patient went to the OR and had a ruptured left tubal ectopic pregnancy.

She had a hemoglobin of eight.

She had three to four liters of blood within her pelvis.

So now let's contrast that patient with this one.

This woman was pregnant and also had an acute onset of pelvic pain.

So the arrows are showing you some hemoperitoneum within the pelvis.

There was a normal right ovary, the left adnexa looked like this.

There was some blood clot and amorphous material, an enlarged left ovary.

This patient went to the OR to have a second look.

She had a ruptured left corpus luteum and the arrow there points to the blue arrow, shows you an early IUP with an intradecidual sign.

This patient, her report initially was read out as ruptured left ectopic pregnancy.

So the gynecologist who was taking care of this patient called me and said, I think that there might be a pregnancy here.

Do you agree an IUP? And I said, absolutely.

So this is a case that that shows you that hemoperitoneum is not specific for ectopic pregnancy.

Do not give methotrexate in the setting of a potential IUP patients who are unstable or who have a lot of pain need to go to the OR for further evaluation.

Differentiating Corpus Luteum from Tubal Ring

So I wanted to take a moment to discuss how to differentiate the corpus luteum from the tubal ring of ectopic pregnancy.

Sometimes these two appearances can look similar and it can be a diagnostic dilemma.

So some of the differentiating features are that a tubal ring will appear more echogenic than the ovarian parenchyma.

The tubal ring, which is composed of trophoblastic material, can appear similar in echogenicity as the endometrium and the corpus luteum is less echogenic than the ovary and less echogenic than the endometrium.

And what about the role of color doppler?

Well this image, this set of images will show you.

So this is a tubal ring of an ectopic.

The color doppler shows a ring of flow.

And this is a corpus luteum also showing ring of flow.

So the color doppler is not helpful.

Are there other things that we can do to differentiate a tubal ring from a corpus luteum if they're adjacent to one another?

So in this case this is adjacent to the ovary, but we can also use something called the sliding sign and apply transducer pressure to show that one moves separate from the other.

Heterotopic Pregnancy Case

So I want everyone to take a look at this case and tell me how they would read it out.

You can do it in your mind.

This is a pregnant patient who had pelvic pain.

She was G five P three, three meaning three ectopic pregnancies and had one and one child.

So if you look here, there is a sac like structure.

She had an IUP and then in the pelvis she also had another sac like structure.

Now this was read out as IUP next case.

So what happened to the patient?

She came back four weeks later.

Now we have a hemorrhagic mass in the area of this sac like structure and also hemoperitoneum.

This was read out as changes of spontaneous abortion with a ruptured hemorrhagic cyst.

This patient went on to get a CT scan and the person who read the CT scan said, let me look back at the initial images and saw that there was a tubal ring of ectopic pregnancy on the first scan.

And they finally made the diagnosis of heterotopic pregnancy.

Do not let the presence of an IUP prevent you from calling a concomitant ectopic pregnancy, particularly in patients who are at increased risk, those who have history of ectopic who have had assisted reproduction.

If you also look here, this tubal ring is as echogenic as the endometrium here and that's another clue.

And there's a yolk sac within this gestational sac.

This is the only case of heterotopic pregnancy that I have seen, but call it when it's there.

Uncommon Types of Ectopic Pregnancy

Cesarean Scar Ectopic Pregnancy

So moving on to a different pregnant female who had heavy bleeding and pelvic pain.

So these are two transvaginal images of the uterus.

It's showing you a sac that looks low lying within the endometrial endocervical canal.

If you look on the transabdominal image, you'll see that the sac is actually located at the cesarean scar.

And this white arrowhead points you to that cesarean scar.

This case had initially been reported as a spontaneous abortion in progress.

This is a different patient showing how color doppler can be useful in showing you the implantation site of a pregnancy.

So the arrows are pointing towards trophoblastic flow in this sac that is implanted in the anterior lower uterine segment.

We also see that there's cardiac activity within the embryo.

And here's the corresponding MRI that had been performed, showing you clearly that this is a cesarean scar ectopic pregnancy.

Now this is another patient who had a low lying sac, low lying gestational sac, also interpreted as spontaneous abortion in progress, the M mode shows that there's regular cardiac activity.

This is a cesarean scar, ectopic pregnancy.

And then if we look back at the initial transabdominal survey, the arrow is showing you the exact location of the gestational sac implantation.

This patient came back nine days later and this is how I got to see the case.

I got to see the case when the sac had passed, but there were retained products of conception manifested by increased color doppler flow with low resistive index.

So the cesarean scar ectopic pregnancy is one that I see commonly missed, commonly interpreted as spontaneous abortion in progress.

It's really crucial to elicit the history of C-section from the patient or see that divot in the anterior lower uterine segment.

When you're looking at the uterus, though it's reported to be rare, I think that the incidence is likely higher and it requires a very high index of suspicion for diagnosis as most patients or a high degree of patients are asymptomatic.

And the imaging findings, the transabdominal scan, I believe the large field of view images are really key in telling you where that sac is located.

Also, you'll see this empty uterine cervical canal and then the color doppler flow can show you trophoblastic flow.

And it's very important to differentiate from a spontaneous abortion in progress.

And if you're not sure, it does no harm to recommend close interval follow-up, you just need to suggest this in the diagnosis.

So this is an example of the history that our technologists take on our patients.

We get all kinds of information when their last menstrual period was if they've had a C-section, any myomectomy, anything else.

We even asked them what their favorite color is.

Just kidding.

Cervical Ectopic Pregnancy

So this is a different patient who was pregnant with vaginal bleeding.

There is a low lying sac.

The sac is located in the endocervical canal.

It is below the level of the internal os on this coronal 2D reformat.

There's a yolk sac within the sac.

And the M mode shows cardiac activity.

So this is a cervical ectopic pregnancy.

We know that if there's a heartbeat within the embryo that it must have implanted at that site.

This is another one that is often confused for spontaneous abortion in progress.

But recommend a follow-up study if you're not sure, 'cause cervical ectopics will persist.

And it's important to diagnose this entity early because if a D&C is performed, that can lead to significant hemorrhage because there's no muscle within the endocervical wall to stop the bleeding.

Interstitial Ectopic Pregnancy

Okay, I want each of you to take a moment to take a look at these three different pregnant patients who have pelvic pain.

So one of these is an ectopic pregnancy.

And so just in your mind, think about which one you would call as ectopic and then I'll go through all these cases.

These are all transverse images of the uterus with the sac.

So let's look at the first two.

So the first one on the left is an IUP angular intrauterine pregnancy.

So the IUP angular is when the gestational sac implants in the upper lateral aspect of the endometrial canal medial to the utero tubal junction.

And there's a large broad-based connection with the endometrium.

The interstitial ectopic pregnancy is when the pregnancy implants in the intramural portion of the fallopian tube.

So these blue arrows show that there's a broad base connection of the sac to the endometrium with the IUP angular pregnancy.

And then on this side, the arrows are showing you that there's a thin band of myometrium separating the sac from the endometrial cavity.

It can be a difficult 2D diagnosis.

And at my institution we do 3D ultrasound and get the coronal view on all patients pregnant or non-pregnant.

And we have found increased sensitivity in making this diagnosis with the 3D view.

So this is a coronal 2D view showing you the location of the interstitial part of the fallopian tube.

So it's this little hypoechoic line.

And then this is a different patient showing an interstitial ectopic pregnancy with the corresponding intraoperative photo showing you the bulging of the gestational sac and the increased vascularity in the arcuate vessels that occur with the pregnancy.

See, this is a different patient who had an interstitial ectopic pregnancy.

There's no IUP, there's a gestational sac kind of bulging off the side of the uterine fundus.

You can see that there's an echogenic chorionic rim trophoblastic tissue is very echogenic and then there is a embryo with the yolk sac inside.

Now this was initially diagnosed or interpreted as a right adnexal ectopic.

So technically that is partially correct, the interstitial wasn't mentioned that it was an interstitial ectopic.

So it's important to differentiate between the two because interstitial ectopic pregnancy is managed differently from an adnexal ectopic in the different parts of the fallopian tube.

Surgical management is usually used to treat interstitial ectopic rather than methotrexate.

Here's a different patient who had an interstitial ectopic pregnancy and here's the cine loop showing you that ectopic gestational sac in the interstitial part of the tube.

And then here, this is that thin band of myometrium that I was talking about that separates the ectopic from the endometrium.

And also note how echogenic that this chorionic rim, the trophoblastic tissue is and how it's similar echogenicity to the endometrium.

So interstitial tubal ectopic is two to 4% of all ectopic pregnancy.

The pregnancy results in a bulge in the uterine contour lateral to the utero tubal junction.

It grows up to 12 weeks due to the surrounding myometrium, but it leads to life-threatening hemorrhage if it is not diagnosed before it ruptures.

So there are many different signs that have been reported in the literature regarding interstitial tubal ectopic, including an empty endometrial canal, a myometrial mantle sign.

The interstitial line sign, the bulging sign.

But I do think that the hypoechoic myometrium that separates the inner border of the echogenic ectopic sac from the endometrial cavity and at the coronal 3D showing you the exact location of the sac, I find those two to be the most helpful.

So what about case number three? So where's this pregnancy?

Well, I didn't discuss until now the presence of A IUP or gestational sac in a uterus with the mullerian duct anomaly.

So this patient had an IUP in the left uterine horn of a sub septate uterus.

Look at how it looks like there's a bulging of the uterus and how it can be confusing.

So this is a case that one of my colleagues called me about and said, can I get a second opinion?

I'm not sure where this pregnancy is located.

So these are transverse and sagittal images of the uterus.

Now would you call this an IUP or would you call this an interstitial ectopic pregnancy?

So how many of you have read these reports?

This appears to be a possible borderline indeterminate, equivocal suspected possible probably of questionable significance.

Clinical correlation needed, maybe interstitial ectopic pregnancy cannot be excluded, but it's probably an IUP.

Now how useful is that to our clinical colleagues?

It's not.

So this one on the coronal 3D, there's no question that it is an intrauterine pregnancy.

So how about this case?

It looks like there are two endometrial canals.

There is a rim of myometrium around this gestational sac.

There's some bulging of the uterine contour.

This is pointing to two different cervical canals.

This was an IUP in the left uterine moiety of a complete septate uterus.

So in which of these is an ectopic? It was number two.

Physiologic Changes in Pregnancy

So now I wanna change gears a little bit to the pregnant woman.

So what are some of the anatomic and physiologic changes that occur during pregnancy?

Well, the changes of pregnancy can mask and delay appropriate diagnosis.

And I know this because I have been pregnant two times.

My second pregnancy was with twins and I had significant symptoms during that pregnancy.

So I know kind of the dilemmas that clinicians can face when a pregnant patient has pain.

Okay, so what happens with the gravid uterus?

So the gravid uterus will start compressing the IVC after 20 weeks and it wreaks all kinds of havoc because it displaces the appendix and the diaphragm upward.

It compresses the distal right ureter.

And in addition, the maternal physiology of hypercoagulability leukocytosis the increased blood volume as well as all the hormones, the progesterone and the prostaglandins result in decreased muscle tone and then can result in physiologic collecting system dilatation as well as lax ligaments.

So the abdominal pain, nausea, vomiting, which are very common symptoms in a normal pregnancy can and they can occur, they can really overlap with pathology and it really causes a diagnostic dilemma and challenge to differentiate pathology from underlying normal physiology.

Imaging Approach for Pelvic Pain in Pregnancy

So what does the ACR say?

The ACR recommends ultrasound as the first line test to perform in a pregnant patient with acute pelvic pain when non gynecologic etiology is suspected.

And again, ultrasound when gynecologic etiology is suspected.

So I wanna go through a few cases.

Appendicitis Case

So this is a case of a pregnant patient with right lower quadrant pain and we've had several wonderful lectures today about appendicitis.

So this is a patient who had acute appendicitis and it's the same appearance as in a non-pregnant patient.

And here's a cine loop showing you a thick appendix.

There's an increased echogenic submucosa, increased echogenicity of the adjacent fat.

There's a little lymph node.

So she had an acute appendicitis.

This was a different patient who had a non-diagnostic ultrasound.

But perhaps if we had done some of the tips that Dr. Jeffrey mentioned, we would've found her appendix.

Her appendix is fluid filled with inflammation on this axial T2 weighted image and sometimes MRI is performed in patients who have difficulty finding the appendix on ultrasound.

So I don't wanna go into the technique too much except to say that it is technically difficult in the third trimester and LPO or LLD position should be attempted as well as the transvaginal approach.

An MRI is used at my institution for problem solving.

So other facts about appendicitis, the acute appendicitis is the most common cause of an acute abdomen during pregnancy.

And it's important to diagnose this early because it can result in fetal loss up to 20% if the appendix ruptures.

Adnexal Torsion Case

So this is a different patient she was 10 weeks pregnant with right lower quadrant pain.

We have images of a slightly enlarged ovary.

You can wonder if there's some increased echogenicity of the ovarian stroma.

Well, this was mentioned but the patient was doing clinically better with medication, but the next day she got much worse.

So she was re imaged and now the ovary has markedly enlarged and she has marked stromal edema and she had a right adnexal torsion.

So as mentioned in the previous lecture, there is a slightly higher increased incidence of adnexal torsion during pregnancy due to the lax ligaments.

And it occurs earlier in the pregnancy, usually between the sixth and 14th weeks of gestation.

Hydronephrosis Case

Okay, this is a different patient, 20-year-old female with right flank pain, 33 weeks pregnant.

Now this is one of the most common things that presents itself to my ER, ultrasound technologists and staff.

We have a right kidney that has hydronephrosis or is it physiologic dilatation due to pregnancy.

What can we do?

Well, we look carefully to see if there's any perinephric fluid.

We look for any renal calculi.

We compare echogenicity right to left and also within the kidney to see if there are any areas that are more echogenic or more swollen than other areas.

We can compare the resistive indices of both kidneys.

There are studies that have shown that an increased resistive index in the side that is dilated can be due to obstruction rather than physiologic dilatation.

And then we can also look at the urinary bladder for jets.

So if you do not see a ureteral jet in the supine position, what you should do is turn the patient left lateral decubitus and then you can often get a right ureteral jet.

And that's because if you think about it, the uterus is compressing that distal ureter and you wanna move that uterus off of the ureter in order to enhance urine peristalsis down the ureter into the bladder.

So this was a patient who had physiologic dilatation of pregnancy.

Comprehensive Imaging Strategy

So we have a pregnant patient who had right lower quadrant pain.

We confirmed an IUP.

This cine loop shows you that there was a normal appendix, there was a little bit of gas within the lumen, there was no surrounding inflammation.

What do you do next?

Do you just send the patient back up to the ER and say normal appendix IUP?

The technologist in this case said, Dr. Rogers, I think that this patient had a lot more pain than I would expect.

So this leads me to how we do it.

So this is our imaging strategy for pregnant patients who present with abdominal or pelvic pain.

So we make sure the patient has an IUP, but if we find the appendix or the right lower quadrant ultrasound is not revealing, what do we do?

Will we survey over the area of pain and we also take images of the gallbladder.

We look at the kidney for stones, pyelonephritis, perinephric fluid, examine the ureter, look at the urinary bladder for debris, look for jets.

Make sure that the appendix and the adjacent bowel looks normal.

Look at the ovary.

Make sure that it also is normal size without signs of hemorrhagic cyst or abnormal corpus luteum.

And also important to look for any fibroids or masses within the pelvis.

So we actually created a new exam code in our system where we have combined an ultrasound abdomen limited with an ultrasound pelvis limited so that we can scan both the abdomen and the pelvis and survey these common areas that can be caused for pain.

And we did this because we saw too many patients with these negative appendix ultrasounds.

Then go on to get an MRI of the abdomen and pelvis and they were found to have pyelonephritis or acute cholecystitis or as an obstructing calculus.

So we thought why not do some additional survey images while we have them an ultrasound and really add value and make the diagnosis the first time around.

So that patient that I showed you the normal appendix, we surveyed the right kidney and we saw some perinephric fluid.

We saw a dilated ureter.

We found a stone within the distal ureter with color doppler twinkling artifact.

And she had an obstructing right ureterovesical junction calculus.

And then here's a different pregnant patient who had right flank pain.

We see a normal ovary.

And then whoops, there's this little echogenic structure within a thick wall tube.

So if we look at that on the sagittal, she had a distal UVJ calculus with urothelial thickening that was causing her pain.

This is a different pregnant patient who had right lower quadrant pain.

The appendix was not identified.

She had an IUP, her ovaries were normal, she was discharged.

She came back two weeks later, but this time the technologist took an image transabdominally and then we could see that she had a degenerating fibroid and that was the site of pain.

So I put this in to make sure to remind everybody that you need to start with your transabdominal images to make sure you don't miss these exophytic fibroids or other masses or free fluid that could be missed if you just use the small field of view.

Transvaginal images, this is a different patient who had a degenerating fibroid.

She, this is the IUP, there's a large heterogeneous fibroid.

This patient had pain over the fibroid and then three years later you could see how the fibroid shrinks and it has that classic peripheral calcification that occurs in degenerated fibroids.

So fibroids are prone to degeneration in pregnant patients due to rapid growth of the uterus and decreased blood supply to the fibroid during pregnancy.

Endometriomas Case

So I'm gonna end now with two of my favorite cases.

These are cases that I think were very important in my career.

And if I look back, you have some, you have these cases that really meant a lot to you and taught you things.

So these two cases were very important to me.

So this is a pregnant woman who was in the second trimester and she had an adnexal mass on the ultrasound.

So in this is in the cul-de-sac and we see one structure on the right and the other on the left we see echogenic nodules with vascularity, particularly on the left side.

And I wanna show you cine loop showing you how there's all of these echogenic nodules that are within these bilateral cystic structures.

So we thought that these were ovaries containing endometriomas and we thought that this was decidualized endometriosis within the endometriomas.

And then you can catch a glimpse of the fetal head right here.

So she had an MRI and it showed the classic appearance of endometriomas.

So we have T1 fat suppressed images showing you the T1 hyperintense hemorrhage.

And she had bilateral increased signal intensity in these nodules that represented the decidualized endometriosis.

So we followed her.

Every four weeks she came back for ultrasound.

And so this went to this actually resorbed three months after delivery.

And it was the longest six months of my life that I held my breath until she came back.

And I got to see that these went away because what can happen is they can be mistaken for malignancy as they mimic ovarian cancer.

And the teaching point is that the T2 signal of the mural nodule should be isointense to the endometrium.

These should be monitored, but know that this can occur in pregnancy.

Intussusception Case

And the last case is this is a pregnant woman who was 32 weeks pregnant and she had significant pain.

They ordered her right upper quadrant ultrasound and the tech said, I think she has acute cholecystitis 'cause she has so much pain.

And I saw that the gallbladder was moderately distended with the little bit of sludge.

The wall was thickened, but it just didn't seem acute cholecystitis, like it wasn't ballooned out.

And I said, what about all these other structures?

So we went back in and I took a look and I asked the patient, did you ever have any surgery?

Because it looked like there was bowel within bowel and an intussusception.

So this was her cine loop that I took.

And she had had a gastric bypass three years earlier.

And what happened was she had a jejunojejunal intussusception with ischemic bowel.

The general surgeon took the patient to the OR and found that it had been necrotic and he actually did a resection and another anastomosis and he was able to save the mother as well as the pregnancy.

So those pregnant patients are at increased risk for JJ intussusception.

Final Thoughts

So my final thoughts, imaging the pregnant patient with acute abdominal pelvic pain should start with ultrasound.

Confirm an IUP and exclude ectopic pregnancy.

Have a high index of suspicion for cervical interstitial and cesarean scar Ectopic pregnancy 3D ultrasound increases sensitivity and also increases specificity and gives you more confidence.

Remember to take the TA images first and remember to use decubitus imaging for jets.

And consider transvaginal imaging for the appendix and distal ureteral calculi image where the patient has pain.

And be the Sherlock Holmes of that patient.

Broaden your search pattern, figure it out, add value as a radiologist to your patients.

Thank you.