Imaging of Non-Fetal Complications of Pregnancy - HD

Introduction

My name is Dr. Teco. I'm a professor of radiology and obstetrics and gynecology at the University of Arkansas for Medical Sciences in Little Rock, Arkansas USA.

The name of my talk for today is Non-Fatal Complications in Pregnancy.

The topic of imaging of non fetal complications of pregnancy is unique in the sense that we are not going to discuss anything that could possibly be wrong with the fetus, but all other factors that can affect the pregnancy outside of the fetus.

Our general categories for discussion are uterine conditions such as anomalies and masses in the adnexa or the uterus, adnexal conditions such as cysts, ovarian torsions, dermoids, and a lot of miscellaneous abdominal conditions such as abdominal pregnancies where the fetus is otherwise normal. Cysts, nephrosis and hydronephrosis, deep venous thrombosis, appendicitis, and the unique case of splenic artery aneurysm.

Uterine Anomalies

As far as uterine anomalies go, the duplication anomalies can lead to infertility or early pregnancy loss. The majority of these cannot be diagnosed or are not diagnosed before pregnancy because they're essentially asymptomatic. Most common ones are bicornuate uterus or uterus didelphys, but if detected early in pregnancy, they can be differentiated from each other.

The more rare unicornuate uterus is difficult to diagnose in pregnancy, but I have a case that I can show you about that also severe retroflexion can lead to incarceration of pregnancy and should be detected early in the second trimester.

So here's an example of a bicornuate uterus with images taken on the transabdominal approach and the endovaginal approach. As you can see, there are two horns of this uterus on the transverse or coronal view, and the fetus is in the right side horn, whereas the left sided horn is empty and all you can see is the thickened decidua of a pregnant uterus.

When you do a transvaginal approach, you can see the top of the fundus of the uterus where you can see a clear division between the two horns of the uterus, the normal pregnancy on the right and the empty uterine cavity on the left. As you go more inferior, you can see that the deformity of the fundus of the uterus is not as apparent, but you can still see the different uterine cavities, the one with the pregnancy on the right and the empty one on the left.

Now what happens when you have a twin pregnancy in a bicornuate uterus? One of the twins implant on one horn and the other twin implants in the other horn, she can see there's a muscular septation that separates the two pregnancies and there are two separate placenta in this dichorionic diamniotic set of twins.

When the placenta grows into the dividing myometrial septum between the two uterine cavities, then that could create some problems with the pregnancy later. But most of the time these are uncomplicated pregnancies and are managed just like singleton pregnancies.

Otherwise, in a case of uterus didelphys, it may be difficult to diagnose the condition in ultrasound unless it is suspected. So these are coronal images of the uterus. Again, there's a pregnancy in the right side of the uterine cavity and the left side of the uterine cavity is empty. As you go down lower, the differentiation between the two uterine cavities becomes harder because now you couldn't see the uterine cavity on the right that contains the pregnancy.

On a longitudinal or sagittal view, you can see the cervix of the right side uterus with the endometrial cavity containing the pregnancy and the left side uterus. Again, you can see the cervix and the corresponding empty endometrial canal. So that is how you can diagnose a uterus didelphys.

Now, most of the time when complications occur, it is very difficult for ultrasound to see exactly what the problem is. So we resort to other imaging modalities like MRI.

In this typical patient who presents with a mass palpable in the vagina since she's a primigravida, there was no prior workup that suggested that she's a uterus didelphys. When the examining obstetrician did a pelvic examination, all she can feel is this very soft and boggy mass in the vagina and the uterus otherwise contained a normal looking pregnancy with no abnormalities seen in the fetus because it was an unusual case and we have no earthly idea what this big mass was in the vagina. An MRI was performed and it shows you that there is a normal fetus, but associated with it is a nonpregnant uterine cavity that is completely separate from the cavity that contains the normal fetus.

What happens is you have a membrane obstructing the vagina at this point and therefore all of the blood that has been shed by the endometrium of the right-sided uterus has been pooling not just inside uterine cavity but in the obstructed vagina. So there is no way that this normal fetus can be delivered vaginally and had to be delivered by cesarean section. So obviously there has to be a vaginoplasty that was done after the delivery to make sure that there is a continuity between the uterine cavity on the right and the distal vagina.

In this transverse or axial view of the MRI exam, you can see the normal fetus in the left side uterus and the obstructed uterine cavity with blood within it in this T one weighted sequence on all three images. So as you can see, this is the mass that was seen on the ultrasound that was soft and boggy.

Uterine Retroflexion Leading to Incarceration

Now the case of uterine retroflexion that could result in incarceration is an unusual, uncommon but unique situation that everybody should be aware of. This happens in about six to 19% of first trimester pregnancies. The uterus is severely retroflexed, not just retroverted, and the retroversion or retroflexion is persistent into the second trimester that leads to uterine incarceration.

So if it is not discovered before 16 weeks the pregnancy, the fetus can grow into the pelvis instead of into the abdomen like it normally would in an anteverted uterus. The incidence is approximately one in 3000 pregnancies and beyond 20 weeks. Persistent retroversion is rare, so if it is remedied before then it might be possible to change the version of the uterus and allow the pregnancy to proceed normally.

So what are the symptoms of uterine retroflexion that causes incarceration? The symptoms primarily are pelvic pressure, urinary retention or incontinence and constipation. Because of the pressure of the fetal head on the rectum, the cervix cannot be appreciated on a physical exam, even on speculum examination because it is retracted very high and anterior in the pelvis, then of course labor is protracted. There's a long delay in the second stage of labor and on ultrasound it could be mistaken for an abdominal pregnancy like in our case.

So here is the longitudinal image of the retroflex uterus that was not suspected before the patient presented in the emergency room. The cervix cannot be seen on a speculum examination, but if suspected may be seen on endovaginal sonography. And this particular case, the cervix is in this area over here and the uterine fundus is down here in the sacral area.

What we call the myometrial shelf is the posterior wall of the uterus that is folded upon itself because of the severe retroflexion of the uterus. So the fetus is really in breech presentation because the cervix is over here, but it looks like it's in cephalic presentation on the longitudinal view on ultrasound because the head was located much lower than the fetal rump, and this was mistaken to be the small uterus and that the pregnancy was outside the uterus.

So the diagnosis of an abdominal pregnancy was suspected and a classical cesarean section was performed. So just to show the confusing picture, this is the longitudinal view. This image was obtained low where you pass through the uterine septum and this is the uterine septum that you see here. The fetus is posterior and the fetal extremities is anterior together with majority of the amniotic fluid as you go up higher.

This particular transverse section was obtained at this level and you can see the amniotic cavity continuous with the body of the fetus with the extremity shadows showing here. So here it's continuous and here it is interrupted because there's an intervening myometrium that is folded upon itself. So as you can see, this created a very confusing picture, an ultrasound leading to the suspicion that we may be dealing with an abdominal pregnancy at surgery.

The obstetrician who delivered the baby drew what he saw at cesarean section. And if you compare it to the published images of a retroflex uterus that resulted in incarcerated pregnancy, you can see how exactly the obstetrician sketch corresponded to the image. So this was exactly the case in this patient.

Actually this patient became pregnant again and had the same phenomenon, but this time we were anticipating the problem. So at 13 weeks the uterus was managed conservatively and manual manipulation of the uterus allowed the fundus to be anteflexed, and the second pregnancy did not become incarcerated like the first pregnancy. So early detection is important, so early manipulation of the uterus can be performed.

Uterine Leiomyomas

What about leiomyomas? This is the most common tumor of the uterus that is benign and about 20 to 30% of women over the age of 30 has this and it goes higher above the age of 40. They're often multiple and asymptomatic unless they become implanted in a endometrial cavity prolapsing from the submucosal position or become a submucosal myoma that would create erosion of the endometrium causing bleeding. Some of them could even prolapse out of the cervix and into the vagina in 4% of women.

The myoma can be diagnosed initially early in pregnancy, but sometimes if it's not diagnosed that early, it could grow with the pregnancy because of the influence of estrogen, about 50% of myomas can grow during pregnancy because of that hormonal influence.

So here's an example of a uterus that is full of myomas. This is the largest myoma down in the lower uterine body. This is a much higher myoma towards the left side of the fundus. And as you can see, this is the placenta. The fetus is over here and it's very difficult to tell what the rest of the uterus looks like because the myometrium basically has been replaced by this multiple myomas, but the pregnancy otherwise appeared normal. The placenta is here and the fetus is normal.

The fetus may have to be delivered by cesarean section. If the myoma acts as a tumor previa. The rapid growth of fibroids can result in degeneration like this is the myoma on ultrasound. It is a central necrotic cavity that can cause severe pain. And if you did an MRI on these patients, you can see the degree of degeneration of the myoma causing pain that can mimic an acute abdomen in the late third trimester. And the pain is usually localized to the fibroid that is degenerating and it has a lucent center that tells you it is necrotic.

When myomas grow in the cervix or low in the uterine body preventing delivery of the fetus vaginally, we call that a tumor previa. Or if myomas grow at the site of implantation of the placenta, it could compromise blood flow into the placenta and result in intrauterine growth restriction.

Spontaneous abortions can occur secondary to the submucosal location of the myoma and ectopic pregnancies can also occur because of tubal obstruction by the myomas. When myomas torsade or become hemorrhagic just like any other mass in the pelvis, they can result in acute abdominal pain in about seven to 8% of cases and can even mimic an acute appendicitis if it is located in the right lower quadrant. And some obstetricians would order a CT examination to distinguish between appendicitis and other causes of severe right lower quadrant pain.

So here examples of tumor previa, this is a myoma growing in the posterior lip of the cervix. The external os is over here and as we go higher you can see where the internal os is. And if this pregnancy grows into the third trimester, you can imagine as this myoma grows, there will be automatic obstruction of the cervical canal that prevents the fetus from being delivered.

Normally, this is another case in a different patient. This is the pregnancy over here that is otherwise normal. The cervix is obscured by this large myoma that is predominantly arising from the anterior wall of the cervix. So these are two more previa.

Now in a case where the uterus is primarily replaced with myomas, you have defined the endometrial cavity to know what kinds of myomas you're dealing with and what the chances of this patient having recurrent abortions because they are unable to establish a good or normal implantation of the fertilized blastocyst into the endometrial cavity. So you have to look for the location of the endometrium in this field that is very confusing because of the multiple myomas.

So once myomas occlude the entrance of the fallopian tube into the uterine cavity, there could be a resulting ectopic pregnancy like in this case over here the uterus ends here and the otherwise normal looking gestational sac is completely outside of the uterus. This is endometrial cavity. So you can tell that this pregnancy is not within the normal uterine cavity. So this is how ectopic pregnancies can occur when there are a lot of myomas distorting the uterine anatomy.

What about premature labor? This is a patient that was diagnosed to have a fundal myoma in the first trimester, came back to the emergency department in the second trimester with severe right lower quadrant pain, which was suspected to be acute appendicitis because of the location and nobody bothered to check her first ultrasound because the symptoms were classic. And as you can tell, this myoma has degenerated and that's what has caused the severe right lower quadrant pain. And by the time the ultrasound was repeated after the CT examination, the fetus was already being passed into the cervical canal. So this was a spontaneous abortion, resulting from premature labor in the second trimester.

So again, it emphasizes the fact that if the patient has a prior examination, it's always beneficial to review that. So you can tell whether the case is really appendicitis or degenerated myoma.

Differential Diagnosis of Myomas

Differential diagnosis of myomas usually is a focal myometrial contraction. This can happen in the first trimester. The patient cannot feel this and like false labor in the third trimester you will just see this an ultrasound. And when this happens, you ask the patient if she's hurting anywhere and she will say, no, this is just myometrium that is contracting and the placenta is anterior. It could look like a myoma if you're not careful.

But the difference is myomas will bulge the external contour of the uterus but only bulge the internal contour of the uterus into the placenta. And the best test is for you to wait, oh, be 45 minutes to one hour and usually that contraction will disappear and the myometrium will show you a beautiful continuity with the surrounding myometrium telling you that the contraction that you see here came from this anterior part of the lower uterine body.

So the characteristics of focal myometrial contraction, again, it only deforms the endometrial surface but not the serosal surface. It has the same echogenicity as the adjacent myometrium and most importantly it disappears with time.

Now, some of them can persist after one hour. So in a very busy clinic, when you have no time to wait for two hours, you could bring the patient back next day and hope that the myometrial contraction has disappeared.

So differential diagnosis, pregnancy fibroid versus bicornuate uterus. You can see how you could mistake the myoma transabdominally in vaginally in a unicornuate uterus compared to a true bicornuate uterus where you have two horns and this one mimics the line myoma that you saw in the other case. So those are just two important points that will help you distinguish these two different entities.

Now this particular case is a huge myoma and this particular case has a bicornuate uterus. Again, very difficult to tell the difference on one picture, but this is a true duplication of the uterus right horn, left horn, whereas this one has only one uterine cavity, but there's a large fibroid preventing vaginal delivery of this fetus.

Adnexal Masses

What about adnexal masses? You diagnose adnexal masses in about 2% of pregnant patients. The vast majority of them are benign and most of them will resolve without intervention. So corpus luteum cysts in the first trimester that should resolve by the second trimester can be followed up. There are theca lutein cysts that occur in some women who have a higher sensitivity to circulating beta HCGs and those will resolve approximately six to eight weeks after delivery, but they could grow into huge masses in the adnexa. I will show you later, 94% of masses are less than six centimeters and can be detected in the first trimester and they resolve spontaneously if they persist into the second trimester. Still you have 25% of them resolve, but much less than those that can resolve in the first trimester detection.

If the mass persists to delivery, they can be managed postpartum and be resected like teratomas or cystadenomas. The problem is sometimes they could mimic malignancies and patients would elect to abort the pregnancy for fear that they may be growing a malignant mass in the adnexa. So one in 1300 live births, sometimes would require removal of the adnexal mass because of potential complications just like hemorrhage or torsion, just like any adnexal mass. And really a small percentage of masses turn out to be malignant and the rate is one in 5,000 to 22,000 live births. So the chances of an adnexal mass being malignant is not really as high as its chances of being benign.

So here's the breakdown of the adnexal masses that are most common associated with pregnancy. Dermoids are about 23% followed by cystadenomas, which is about the same frequency fibromas very common and these other cysts that are less common than the top three.

This is where magnetic resonance becomes helpful. It can define the organ of origin, it can tell you what the nature of the mass is and it could decrease the need for surgery during pregnancy because it will define the mass better for you.

So here's an example of a corpus luteum cyst that's the hemorrhage. It's usually a very clear simple cyst that occurs in the first trimester and are usually asymptomatic only detected on ultrasound for routine dating for instance. If however, the pregnancy is evaluated because of pain, it's because the corpus luteum has hemorrhaged into the cavity and you can see layering debris of hemorrhagic fluid within the corpus luteum. And here's again another example. Normal pregnancy in the first trimester with an associated corpus luteum that was asymptomatic.

Now, cystadenomas typically are simple, but they can also have very thin septations. This is reverberation arising from the anterior wall of the uterus. The septations that are thin are classic for cystadenomas. The problem however, is cystadenomas can be borderline malignant. They could have flow on the rim and sometimes their septations can be thicker and you really have a hard time distinguishing a cystadenoma from a cystadenocarcinoma.

So some people would go ahead and do an MRI hoping to look inside the mass and see if they can find some other evidence of malignancy or some people would just do a follow-up and see if it grows or develops in more malignant characteristics. But it is very common associated with pregnancy this condition called hyperreactio luteinalis is really just bilateral theca lutein cysts in very large ovaries.

So in this particular patient you have a right-sided cystic mass in the left-sided cystic mass and they average between 17 and 13 centimeters. Now in spite of their size, these were not palpable clinically, which is typical for this particular case. And as bad as they look, it is very important to remember that these can really regress and become normal at six to eight weeks after delivery of the fetus.

These are the same types of cysts you see in molar pregnancies, or in ovarian hyperstimulation syndromes in women on fertility drugs.

This is an unusual case of a combination of many factors and the anatomy only became clear to us after the surgery because at presentation in the emergency room, this patient was in real severe pain. And as you can see, there's a normal looking first trimester pregnancy and there's an associated small corpus luteum cyst, but there's a big cystic mass that is separate from the urinary bladder. And in addition to that, at the site of the pain is an ill-defined solid looking mass at surgery.

This ill-defined solid looking mass was the torsed ovary that was causing the pain. The cystic mass that appeared simple was the cystadenoma and this is a corpus luteum cyst.

Now, if surgery has to be performed because for instance torsion, just like in this case or the removal of an associated cystadenoma, it is best performed in the early part of the second trimester when the uterus is least irritable. To diminish the incidents of spontaneous abortions, dermoids can look like anything in the pelvis. It is the biggest mimic of all the adnexal masses.

The classic dermoid will show you multiple tissues within the mass. There's a lot of fluid components. There's components that are predominantly fat. These are floating hair strands that you can see. Some of them can have solid components and a lot of times they're asymptomatic and most of the time they are benign. But there are borderline dermoids that could present a problem. And sometimes we have to resort to magnetic resonance imaging to confirm that this is indeed a dermoid.

In this particular case, you have again a normal first trimester pregnancy at 11 weeks. When in vaginal examination you can see a typical dermoid with solid components called the dermoid plug and the suspension of fat and fluid that you see together with the mass. If you perform an MRI, you can see that this solid mass over here is really the fatty portion of the dermoid together with other tissues that may be in it. And when you suppress that, you could see that the fat suppresses, but the rest of the dermoid is better defined after fat suppression.

Abdominal Pregnancies

What about abdominal pregnancies? They are special types of ectopic pregnancies. They're not like the interstitial pregnancies that can rupture or the tubal pregnancies that can grow for a few weeks and then create symptoms and can be detected. Abdominal pregnancies are a product of fertilization of the egg by the sperm within the distal fallopian tube.

But instead of proceeding to implant into the uterine cavity, it either ruptures out of the tube and looks for other places to implant in the abdomen or sometimes the theory suggests that there's retrograde peristalsis and instead of rupturing through the tube, the fertilized egg travels backwards into the fimbria of the tube and looks for an area in the abdomen where it can implant. So it could really be anywhere. It could implant under the liver in the left upper quadrant near the spleen. On the meso bowel on top of the uterus, anywhere you can find a good blood supply that can support the placenta.

So the patient feels very vague, mild symptoms of abdominal pain. Occasionally they may have some vaginal spotting, but these abdominal pregnancies, once they establish good blood supply, can carry to near term before being detected. And the ultrasound findings can be subtle.

The hints that you will have to make the diagnosis of abdominal pregnancy is a very unusual fetal lie, like it's not, you're straight up and down longitudinal, breech or cephalic presentation. It's either oblique or transverse or some very unusual position. And the placenta is not normally shaped like an elongated mass in a normal pregnancy. It could be round, it could be irregular, it could be unusual in location in the pelvis. That should give you the hint that you're not dealing with a normal implantation.

The most important thing to do is to really have the discipline to establish the continuity between the cervical canal and the uterine cavity or between the cervical musculature and the myometrium superior to it. So you should always get that image where you have the vaginal canal lined up with the cervical canal lined up with the uterine cavity. And take that picture to know that the pregnancy that you're looking at is really within the uterus and not outside.

If you can't see the cervix below the presenting part, no matter how much you try, that's another hint that you may be dealing with an abdominal pregnancy. And sometimes the fetus is very, very close to maternal bowel gas, which should never happen because there should be an intervening myometrium. And if you see that the maternal gas is basically interdigitating between fetal parts, then you know something's wrong. And of course you should follow the myometrium. A normal pregnancy should have myometrium completely surrounding the fetus. If you cannot detect that, and again, that's another good sign you may be dealing with an abdominal pregnancy.

So here's the first case of abdominal pregnancy that I got involved in. This is the vagina, this is the urinary bladder and the transabdominal approach. We thought we can establish cervical continuity with the uterine cavity, but we never really saw the cervical canal. And then we went up higher into the pelvis and thought that we were dealing with a uterine myoma in the anterior wall of the uterus because this is the fetus. And then we realized that this is maternal gas in the bowel, which was located between the fetus and what we thought was the uterine myoma. So something was not right.

And then if you look at the back of this pregnancy, you cannot find myometrium here. All you see is the fetus, the placenta and bowel gas. And the most telling part is this is a transverse view of the abdomen, the maternal abdomen. This is the maternal spine and this is the right common iliac artery. And every time it pulsates you can see the body of this fetus bounce with it. And again, there's no myometrium behind and this is the placenta.

So because of these unusual findings, we decided to do an MRI. This is another patient that shows you what an abnormal looking placenta would look like in an abdominal pregnancy. And again, there's no continuity of the cervical canal with the myometrial canal and maternal gas, again intimately related to the fetus. So here's the corresponding MRI exam. This is the uterus, not the cervix because the placenta has basically implanted on top of the small uterus and the fetal brain is here under the colon close to the liver and on on the transverse view. The rest of the fetus is really curled up in the right upper quadrant. Again, this is the abnormal looking placenta and this was established as an abdominal pregnancy really late in the third trimester another MRI abdominal pregnancy.

You can see on a single sagittal view, you would think that this is an intrauterine pregnancy, but on the coronal view, you can appreciate that the pregnancy in the placenta are really outside of the uterus. And you know that's the uterus because when you do a T two weighted image, you can see the endometrial canal here and it's completely separate from the placenta and the fetus that has implanted outside the uterus. So MRI makes a diagnosis of abdominal pregnancy pretty accurately.

So at surgery you will see the uterus and the abdominal pregnancy growing right next to it and you can start seeing the baby being delivered. And believe it or not, this baby went home the normal number of days postpartum and they were able to deliver the placenta. Although parts of it remained when you have a placenta that's implanting on bowel or liver or any mesentery, you can only remove as much as you can, but not all of it. And hopefully the body will take care of it and not create any trouble in the future.

Right after that diagnosis was made, we had this case an MRI because we thought this was the uterus and that we were dealing with an abdominal pregnancy. So we did an MRI, and this is really just a very weird looking anterior uterine myoma. There's the cervix in continuity with the endometrial canal that contains the normal fetus. And as you can see, the cervical wall is in direct continuity with the posterior uterine wall. So this was a false positive diagnosis for an abdominal pregnancy.

Another weird one is a large dermoid with a lot of contents in it that mimicked a placenta and a dead baby superimposed on top of what looked like a uterus that has pregnancy in it. It became very confusing. We thought we had a twin pregnancy. One was growing outside as an abdominal pregnancy and the other one was within the uterus. So that was a another false positive diagnosis. So dermoids could be problematic.

This is the only example that I have of a unicornuate uterus. And basically it is an abnormality where there's only one horn in the uterus, but it is a very restrictive horn. This is the placenta over here. This is the otherwise normal fetus and there's very little space for the fetus to grow. This is the cervix underneath here and it's very difficult to see amniotic fluid surrounding the body of these fetus. This is a longitudinal view, this is the spine of the fetus. And again, this was mistaken as an abdominal pregnancy because of its very unusual position in the abdomen. And we thought the cervix was the small uterus. So another pitfall in the diagnosis of an abdominal pregnancy.

Biliary Disease in Pregnancy

So we now go to biliary disease that can complicate pregnancy. Pregnancy tends to increase the incidences of gallstones by about 12 to 13%. It's because progesterone causes gallbladder atony. It increases the cholesterol in bile, it has an abnormal phospholipid concentration, and stones can occur anywhere from three per thousand live births and increases with advancing gestation.

So in a mother that complains with right upper quadrant pain after the onset of pregnancy, this should be the number one differential diagnosis you should entertain. So an ultrasound, typical gallstones, you know, with acoustic shadowing that move on a lateral decubitus position is classic in the diagnosis of stones. Obviously if you try to elicit a Murphy sign sonographically by pressing the transducer on the gallbladder fundus, your diagnosis of acute cholecystitis becomes established.

Sometimes some of the stones will go down into the common bile duct causing obstruction of the common bile duct. And this can be diagnosed with MRCP using thick slab imaging heavily T two weighted and it shows you dilated intra hepatic bile ducts in a large common bile duct, secondary to the obstructing stone. And if intervention is needed in a pregnant woman, ERCP can be performed, but could be a little problematic if the uterus makes visualization of the ULA difficult.

Urinary Tract in Pregnancy

What about the urinary tract in pregnancy? The smooth muscles relax and the uterine compression can lead to dilated ducts in the kidney and ureter. So the right ureter is known to be more dilated than the left, especially the distal ureter that tapers below the iliac vessels. You cannot see in ultrasound, it would normally revert to normal by six weeks.

It also increases the protein and glucose in the urine and the pain may be atypical and the diagnosis may be difficult. On urinalysis, you can see a lot of red blood cells in the urine and doing a single shot plain film of the abdomen radiographically may not show you the stone. So before you jump into doing a CT or an MRI to look for a stone in the distal ureter, you should do ultrasound first. And this can be done either transvaginally or transabdominally with a full bladder. But more and more people are trying to diagnose this transvaginally.

This is an example of an ultrasound image of a dilated right kidney dilated the hydronephrosis and calyces and continued dilated ureter on ultrasound, you can't see beyond maybe two to three centimeters of proximal ureter. So if you wanna see the distal ureter, you have to resort to MRI or ct.

Occasionally it will just be a dilated right collecting system that is physiologic in pregnancy and you may not find a stone. Some people may go ahead and do follow up examinations depending upon patient's symptomatology.

Recently they have described what they call a twinkle artifact that increases detection of stones in the kidneys and sometimes in the ureter. A twinkle artifact is a doppler imaging artifact that is caused by the intrinsic noise or called phase jitter within the Doppler machine. What it does is it creates these color doppler reverberation looking artifacts because of the reflection from the rough surfaces of the stone. So the rougher the stone, the more twinkle artifacts you see, and this is color doppler twinkle artifacts in multiple stones within the kidney and they could mimic gas within the collecting systems.

Pitfalls in Stone Disease in Pregnancy

Pitfalls in stone disease in pregnancy, sometimes you would think that doing ureteral jets, we'll color doppler can exclude a stone in a distal ureter, but they're unpredictable. They could be difficult to see because only about 15% of patients may have absent ureteral jets on one side. So if you see it on the left, but not on the right, you couldn't say that the right is obstructed because you may not be able to witness it as it's doing the jets.

Sometimes you could have an over distended urinary bladder that can create some partial obstruction to the distal ureter. So here you have a stone that could be just right at the trigone that may be blocking the ureteral jet on the right side. But again, the ureteral jets are not very reliable as diagnosis for obstruction.

Other causes of flank pain, while you could just have renal obstruction from other causes, you could have the stone at the ureterovesical junction. They could be echogenic if you can detect them on ultrasound, either transvaginally or transabdominally. But you also could have flank pain because of infection. Urinary tract infection or cystitis can cause non gynecologic or other causes of non gynecologic gynecologic pelvic pain can mimic stone disease. So you always have to think about those other causes.

Deep Venous Thrombosis in Pregnancy

Pregnant women are also prone to developing deep venous thrombosis and they may be difficult to detect an ultrasound, but when you do, it will look just like any clot filling up the whole vein. You see the corresponding artery has normal doppler echoes and then the corresponding vein does not show echoes. And this one happens to be seen well because it is right below the lower uterine body. And you can see in the right groin that there's a huge distended vein. And on venography you can see confirmation. We don't usually do venographies anymore because we can see the clot as well on CT or MRI.

Splenic Artery Aneurysm

And finally, this is this unusual lady who comes from the emergency room in the middle of the night with pain. She's known to be pregnant late second trimester. This is the fetal head presenting and if you look at the fundus of the uterus, you can see what looks like a mass. And everybody thought, okay, well she's having pain because she has a myoma, maybe degenerating, so therefore, we should just wait and see. But her pain became worse within a few hours and so they brought her back. And this time we were able to see fluid not only under the right lobe of the liver, but also fluid surrounding the spleen. And at the hilum of the spleen, we have this rounded structure that if you turn on the color doppler tells you that this is a vascular structure. This is a large splenic artery aneurysm.

And what happened here is the aneurysm has already ruptured by the time we got to her and she was leaking and having a lot of peritonitis secondary to the irritation of the blood and the peritoneum. And just to verify that is indeed an aneurysm. You obtain wave forms that tells you that you're dealing with a combination of wave forms characteristic of arterial flow.

So they did the CT just to determine whether they should intervene or not. So these are images obtained in the upper abdomen and this is in the mid abdomen. As you can see, all these fluid around the liver, around the spleen going into the pelvis is all hemorrhagic fluid. So here as a very high attenuation secondary to fresh blood, and if you go down lower, it even gets worse as you go down into the pelvis. Here's the pregnancy surrounded by blood within the peritoneal cavity. That's pretty massive.

So ordinarily if you have a splenic artery aneurysms that are less than three centimeters, the chances of rupturing are less than if you have one that is greater than three centimeters. So those small splenic artery aneurysms tend to be observed or followed up, but when they rupture like this, it may be too late to save the fetus, which happen in this case because of the irritation this fetus was spontaneously aborted at the time of diagnosis. So again, there's really nothing you can do to prevent that from happening because obviously this is a congenital problem, but the diagnosis could have been done a little earlier before the rupture of the aneurysm.

Conclusion

So in conclusion, we continue to do ultrasound as our screening modality in the evaluation of pregnant patients because of its known advantages. It's low cost, has real time capabilities easily accessible and available in many emergency departments. And many of these non fetal complications of pregnancy can be diagnosed because of the increasing use of ultrasound in pregnancy.

But when there is doubt as to what the diagnosis is, should never hesitate to do complimentary imaging like CT or MRI to make sure that we are not jeopardizing the safety of the patient and the fetus and emergency conditions need to be differentiated from those that can be managed postpartum, such as benign adnexal masses that probably should not deter the patient from waiting until after the postpartum period to take care of the problem.