Tag Archives: obstetric

Optimize Screening of the Fetal Heart

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The keys to optimizing screening of the fetal heart are to understand how the ultrasound machine’s functions and controls can affect your image, utilize the entire maternal abdomen, adjust your image presets, and optimize your angle of insonation. So how do you do all that?

You start with the transducer. Be sure to select a transducer that allows for adequate penetration and optimal resolution. All transducers have different operating frequencies and capabilities; high frequencies produce better detail resolution but, of course, with limited sound penetration. These frequencies can be applied in all trimesters, particularly since the advent of high-resolution transducers, which are helpful when imaging delicate heart structures, such as the valves and vessel walls. If, however, the imaging is subpar with a high-frequency transducer, switch to a low-frequency transducer, which is more useful in your patients with a high body mass, in the late second trimester, in the third trimester, and in the event that there is also polyhydramnios syndrome, even when there is rib shadowing. Keep in mind too, that transvaginal imaging is helpful for evaluating the fetal heart in the first or early second trimester, in the event that there is suspected fetal cardiac abnormality, and even when maternal body habitus causes imaging to be difficult.

For your next step, adjust your image presets to optimize your temporal resolution so that you maintain a high frame rate of greater than 25 frames per second. A few of the technical settings that affect temporal resolution are the frame rate (in Hz), frequency selection, depth & focus, sector angle width, and zoom magnification. The better the temporal resolution, the improved detail resolution. To optimize your image, avoid unnecessary depth and make sure your focus is on the region of interest. A multiple focal zone may be applied to structures that don’t move, such as the placenta, but when looking at the 4-chamber heart, you will need a single focal zone. In addition, adjust your sector angle width. Reducing it increases lateral line density, which improves the image quality. Finally, make small adjustments to your settings, such as applying speckle-reduction imaging, adjusting the dynamic range (more or less gray), and scanning in different tones.

When incorporating color Doppler, the color box, color gain, wall motion filter, velocity scale/pulse repetition frequency (PRF), balance, and angle of insolation can each affect the image. The color box slows the frame rate by a significant degree so the smaller the color box, the higher the frame rate. Set color gain initially on low (ie, less color) and gradually increase it until you have optimized the amount of color. The wall motion filter eliminates signals caused by wall motion and low velocities. The velocity scale is the range of mean velocities or PRF in the region of interest. If it is too low, it can produce aliasing, which could lead to a misdiagnosis; too high and the low-velocity flow will not be displayed. Here is a sample of potential ideal velocity flows:

High-velocity flow (>60–80 cm/sec)Low-velocity flow (<30 cm/sec)
Atrioventricular valvesPulmonary veins
Semilunar valvesBicaval (IVC/SVC)
The great vessels (3VV)Evaluating atrial and ventricular septum
The scale is dependent on factors such as body mass index and fetal positioning within the uterus.

The balance allows you to display how much grayscale and color Doppler information you would like to see. Reducing the balance will show grayscale elements within the color box. And, finally, the angle of insonation is very important to keep in mind as the signal from the transducer should be parallel to the direction of blood flow.

J of Ultrasound Medicine, Volume: 35, Issue: 1, Pages: 183-188, First published: 01 January 2016, DOI: (10.7863/ultra.15.02036)

One of the major challenges in ultrasound imaging is scanning a morbidly obese patient. This is a result of the increased distance between the transducer and fetal anatomy, causing degraded resolution. Some techniques for optimizing your imaging in these cases include scanning above the tissue, when the patient’s bladder is full, through the umbilicus, or when the patient is in the Sim’s position (with the patient on their left side), which allows the extra tissue to fall to the left side. Also, keep in mind that when scanning an obese patient, the color doesn’t always fill in. Lowering the color attenuation can help clarify the image.

So, remember, the key to optimizing your fetal heart imaging is in understanding your machines’ functions and controls and how they can affect your image, utilizing the entire maternal abdomen, adjusting your image presets, and optimizing your angle of insonation!

To learn more and see case scenarios, see the American Institute of Ultrasound in Medicine’s (AIUM’s) on-demand webinar with speaker Mishella Perez, MS, RDMS, RDCS, “Fetal Heart Image Optimization: The Key to Screening”, from which this post was adapted. AIUM members can access the webinar for free.

Interested in learning more about fetal imaging? Check out the following resources from the American Institute of Ultrasound in Medicine (AIUM):

The Eyes and Ears of The Patient(s)

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I began my ultrasound career in 2001 after graduating from the DMS program, but truth be known, it began sooner than that. I was incidentally placed at a maternal-fetal medicine clinic to do a rotation to get my clinical hours due to a preceptor being absent for an extended period of time at my “established” site, unbeknownst to me or anyone else just how much this would impact not only my career but my life.

When I was exposed to high-risk obstetrics (OB), I was instantly intrigued. I was told that I would need a minimum of 5 years of scanning experience before I could enter that field. For those that know me, know I’m always up for a challenge! I was prepared to do what it took.

At the end of my rotation, my preceptor, the one who would become the most impactful mentor I’d ever had, Ivy Myles, asked if I would be interested in returning to finish my clinicals at their practice, of course, I jumped on it.

Fast forward to today, I have learned that we, as sonographers, are the eyes and ears of the patient, and being in high risk, we are the eyes and ears of TWO patients. That is an incredible amount of responsibility and should not be taken lightly.

So, what does it mean when the job you love comes with so much responsibility? It means that we are in a position to advocate for the patient(s); we listen to them, ask questions that may seem out of curiosity to the patient, but in fact, tell a story of what may or may not be happening with mom and baby. I believe that we are not “picture takers,” we are “storytellers,” presenting our cases to the providers that have learned to trust our skills, talents, and insights.

Over the years, I have fallen more in love with this field and it has become a passion of mine. I want to learn more, teach more, and do more. I have a special place in my heart for the students and new sonographers that want to delve into the high-risk world because of how I entered this field. So, I carry on what my preceptor and mentor gave to me. She saw my skills and my heart for the field and gave me a chance. When a patient is told they are “high risk” and need specialty care at a perinatal center, this is typically not taken lightly. The patient is concerned for her baby and herself. In most perinatal centers where I have worked, the sonographers have a unique position and freedom to talk with our patients, explain the ultrasound, any concerns we may have about the ultrasound (without a diagnosis), we are able to provide a tour of their baby before they meet them, and let the family see their baby being a baby before meeting them on the outside. What a blessing for all!

Carrie Bowen, RDMS, RDCS​, is a sonographer at Perinatal Associates of New Mexico.

Interested in learning more about obstetric ultrasound? Check out the following posts from the Scan:

Ultrasound Imaging of Obese Pregnant Women

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As the rate of obesity continues to increase worldwide (last reported by the CDC as 42.4% as of 2017–2018), it has become even more evident that there is a great need to improve fetal cardiac visualization in obese pregnant women. Less than 50% of morbidly obese women have successful fetal 4-chamber and outflow tract visualization, compared to almost 90% of nonobese women.

Obese women are also significantly more likely than normal-weight women to have children with a congenital heart disease, with an even higher risk in morbidly obese women, who give birth to children who have higher odds of having atrial septal defects, hypoplastic left heart syndrome, aortic stenosis, pulmonic stenosis, and tetralogy of Fallot.

And when obese pregnant women have reduced rates of complete anatomic surveys, lower detection rates, and increased risk of fetal anomalies due to less than perfect anatomy visualization, how do we improve the fetal cardiac visualization?

A team of researchers from Eastern Virginia Medical School looked into whether ultrasound (US) imaging in early gestation could help.

Amara Majeed, MD; Alfred Abuhamad, MD; Letty Romary, MD; and Elena Sinkovskaya, MD, PhD, performed a study in which all study participants (obese pregnant women) with a gestational age of 13 weeks to 15 weeks 6 days, underwent an US exam using a transvaginal or transabdominal approach and color Doppler US for fetal cardiac screening, which they defined as complete when all components of the 4-chamber, right ventricular outflow tract, left ventricular outflow tract, and 3-vessel views were clearly visualized. The participants also underwent a traditional transabdominal examination at 20 to 22 weeks, and if that exam was incomplete, underwent another 2 to 4 weeks later.

What they found was that the addition of early-gestation US to the 20- to 22-week US exam of obese pregnant women substantially improved the visualization of fetal cardiac anatomy. And for the women with a BMI of greater than 40 kg/m2, the cardiac screening completion rate was even higher (significantly so) for the early-gestation exam plus a traditional exam (90%) than for the traditional exam plus the second traditional exam (72.7%).

Adding an ultrasound exam at a gestation age of 13 weeks to 15 weeks 6 days substantially improved the visualization of fetal cardiac anatomy, particularly for the women with a BMI of greater than 40 kg/m2. Having complete or more complete anatomy screening can enable an earlier, accurate diagnosis.

To read more about this study, download the Journal of Ultrasound in Medicine article, “Can Ultrasound in Early Gestation Improve Visualization of Fetal Cardiac Structures in Obese Pregnant Women?”. Members of the American Institute of Ultrasound in Medicine can access it for free. Join today!

If you have any questions about the study, please ask in the comments; the authors of the article will be happy to respond.

What’s Your Dialogue?

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Ultrasound image of a uterus showing the crown rump length of the fetus is 0.34 centimeters.

Beneath the paper drape of the “2:30 OB Confirmation” lies your next patient. Despite the application of the ultrasound study performed, a variety of stressors wreak havoc on a patient’s mental state prior to examination. The impact of what we say and how we say it, or the very lack of it, can shape a person’s view of testing, staff, or even healthcare as a whole. Yet, how much of an emphasis in ultrasound training is placed on effective communication? Especially in obstetrics where early pregnancy loss is prevalent, a blank stare at the monitor and averted eyes feels disconnected and insensitive. Let’s ask ourselves:

  • How do we, as ultrasound providers, communicate with our patients?
  • Do we attempt to provide comfort or empathy when needed?
  • How important is this interaction to our patients?

We owe it to quality patient care to take a deeper dive.

In settings where our patients show fear, stress, or grief, what’s your dialogue?
How should it look and sound?

Perhaps your patient, waiting nervously under the drape, presents with a poor OB history. Performing an ultrasound examination should encompass more than the stoic mechanical bedside manner. We should engage with the person behind the diagnosis code.

We see it often in OB. Despite reassurances of last week’s scan and normally-rising labs post early spotting, the patient leaves her appointment only to consult Dr. Google where she absorbs every related link about bleeding in pregnancy from previa to placental abruption. It’s been the L O N G E S T week of her life, and she’s sure fate will deliver yet another D&C instead of the child she desires. Miscarriage is the kind of trauma that leaves a woman emotionally scarred and fearful that history will repeat itself. It’s imperative we contemplate the real trepidation some patients feel for their examinations—and act accordingly.

Photo credit: Kat Jayne, pexels.com

For the brief time a patient resides in our care, we sonographers control the environment. We drive the equipment, manage the time, and guide our patients. It is completely within our power to greet them with warmth and direct eye contact, to adopt a caring tone in our explanations, to ensure comfort in our care, and to assure answers for their questions—where we can.

It’s a fine balancing act, isn’t it? …A tightrope walk between what we sonographers can share with an inquiring patient and what we cannot. Though protocols vary, we all surely must learn what information we are allowed to impart. Precisely how we convey it is up to us. After all, our patients must disrobe before a perfect stranger who is not their physician; in turn, we must overcome the propensity for a swift robotic contest against the clock to be more attentive. We may not manage a patient’s care, but for a short time, we are a patient’s provider and caregiver. The interchange with our patients is as much an integral part of our job as is concise reporting.

Effective patient communication should be a cornerstone of every curriculum and commence as early as learning sagittal versus transverse. Every veteran sonographer who relishes the confidence of cultivated skill and experience began the same way. Typically, navigating this technology for most students requires a long learning curve to perform it well and accurately. It’s quite easy for the initial focus to lie with capturing textbook images, not connecting with the patient. Learning appropriate and competent dialogue is as imperative as exam protocol. The new sonographer must observe and mimic this personal interaction before the first steps beyond the classroom.

Photo credit: Stas Knop, pexels.com

Conversely, the skillful sonographer, buried in the demands of a hectic patient load, may lose the tendency over time to prioritize this communication. Juggling the demands of a full schedule with urgent add-ons and after-hours call, we sometimes end up fanning the flames of burnout where a slide into the hurried robotic pace of patient-in, patient-out feels unavoidable. Don’t lose sight of the importance of your work and who depends on you. Every patient you scan lies on your table, and your’s alone. We are each responsible for the level of quality care we provide.

Now, examine your own daily patient interactions. Are they mechanical and rushed? Or do you take the time to employ earnest conversation? Do you attempt to allay fears or offer an empathetic tone when needed? Do you extend the care you would want, need, and expect if on the receiving end of healthcare? I challenge each of you to put forth the very same degree of consideration you’d like for your mother, your sister, your daughter, yourself…if the white coat fear was your own, if the anxiety of a test result was your own, if the pregnancy loss was your own. The appreciation our patients show can mystifyingly renew a sense of purpose in our work today and fuel our career tomorrow.

So, what’s your dialogue?

Sandra M. Minck, RDMS, is the creator of UltrasoundUnwrapped.com and @ultrasound_unwrapped on Instagram, a resource for accurate ultrasound information for expectant parents. She is the author of Ultrasound Unwrapped: A Pregnancy Image Guide, soon to be published.

Interested in learning more about communicating with patients? Check out the following posts from the Scan:

Saving Lives With Ultrasound: How to Improve Placenta Accreta Spectrum Antenatal Detection and Management

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“You think of pregnancy as joy, laughter, preparation for a new life. Never did I think it was possible that I could risk losing my uterus or my life because of pregnancy.”

If I had a nickel for every time I heard this from a patient diagnosed with the placenta accreta spectrum (PAS)…

Many have never heard of PAS, where the placenta grows past the endometrial lining of the uterus and into or beyond the uterine wall. Blood vessels tend to be engorged due to the increased uterine blood supply to support pregnancy. New, abnormal vessels are recruited. This makes surgical management tricky at best and the risk for massive hemorrhage a reality at worst.

The good news is that antenatal identification of PAS has been proven in multiple observational studies to lead to improved outcomes. Why? Antenatal detection allows patients to be referred to centers with experienced, multi-disciplinary PAS teams.

In the U.S., a majority of patients with PAS undergo a cesarean hysterectomy, the definitive surgical approach. Other centers may offer alternative approaches, including delayed hysterectomy, partial myometrial resection, or truly conservative management, where the placenta is left in place after delivery until the placenta resorbs, gets expelled, or complications arise. No matter the approach, the risk for major morbidity and mortality is proven to be lower when patients are cared for by experienced, multidisciplinary teams.

PAS encompasses placenta accreta, increta, and percreta, and truly represents a broad spectrum of abnormal placentation.

Why the sudden interest in PAS?

Many experts believe that the incidence of PAS is rising worldwide. Most large population-based studies show that the incidence ranges more consistently between 1 in 1000 to 5 per 10,000 pregnancies. While these rates are lower than traditionally cited (1 in 200 to 500 deliveries, as cited from referral centers), the increased risk for morbidity and mortality drive the need for vigilance when evaluating patients. PAS can be detected with ultrasound with 80–95% sensitivity and specificity in expert centers, but the overall antenatal detection rate runs closer to 40–50% according to population-based studies.

How is PAS detected before delivery?

Ultrasound is the cornerstone, as it is noninvasive, relatively inexpensive, and readily available. Some experts consider referral to MRI if the placenta is not adequately seen. MRI is not a superior, however, but rather it permits visualization of the placenta in a different way. The sensitivities and specificities of ultrasound and MRI are similar. As with imaging modality, diagnostic accuracy depends upon the expertise of the people acquiring and interpreting the images. Referral to experienced imaging centers is recommended for patients with significant risk factors or if PAS is suspected.

What are the risk factors for PAS?

Most commonly, previous cesarean deliveries and placenta previa. Other risk factors include myomectomy, endometrial ablation, smoking, and in vitro fertilization.

How can we improve antenatal ultrasound detection?

Using standardized protocols and checklists to “prime the mind” are important.  One cannot find what one does not seek, therefore, it is important to evaluate the placenta thoroughly.

A few quick tips:

  1. Fill the bladder. The full bladder creates an acoustic window that improves visualization of the lower segment. Irregular placental bulging and hypervascularity can also be seen with better accuracy.
  2. Angle matters. The lower uterine segment curves away from (perpendicular to) the transabdominal probe. This causes shadowing. Position the patient bed head down and angle the probe such that the handle parallels the patient’s thighs and the lowermost segment appears clearly.
  3. Image transvaginally. Using a transvaginal approach identifies deep, cervical invasion and can provide a clear view of the lower uterine segment.
  4. Interrogate the ENTIRE placental surface. Sweep sagitally left to right, transversely both the midline and along each (to look for parametrial involvement).
  5. 3D and color Doppler. These imaging tools can help identify hypervascularity and bladder contour irregularities.

If there were ever a silver lining, the spotlight on PAS as is fueling us all to work to identify best practices and to improve training at all levels.

Karin A. Fox, MD, MEd, FACOG, is an Associate Professor, Associate Fellowship Director, and Clinical Director of the Placenta Accreta Spectrum Care Team in the Division of Maternal-Fetal Medicine, Department of OB-GYN, at Baylor College of Medicine, as well as is Medical Director of Maternal Transport for the Kangaroo Crew at Texas Children’s Hospital Pavilion for Women.

Interested in learning more about placenta accreta spectrum? Check out the following resources:

Ultrasound at the Zoo

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Zoo medicine is quite the paradox. In one way, zoo veterinarians are specialists in that what we do daily; it is very unique and specialized and there are few licensed veterinarians that are employed as full-time clinicians in zoological parks. On the contrary, zoo veterinarians are also the ultimate general practitioners as our patients include everything from invertebrates to great apes and elephants (and all life forms in-between)… and for this wide variety of patients, we attempt to be their pediatrician, surgeon, dermatologist, cardiologist, radiologist, etc. I am fortunate to be the Senior Staff Veterinarian at the Louisville Zoo in Louisville, Kentucky.

In terms of imaging modalities, most zoo hospitals are equipped with plain radiography (film or digital) and have some ultrasound capabilities. A few of the larger zoos in the country have computed tomography (CT) in their on-site hospitals. In Louisville, when one of our patients requires advanced imaging, we make arrangements with local facilities with CT or MRI capabilities.

For ultrasound imaging, we have a portable Sonosite M-Turbo unit with both a curvilinear, 5-2 MHz transducer for primarily transabdominal imaging, and a linear array, 10-5 MHz transducer for primarily transrectal imaging. In addition, we have several donated large rolling Phillips Sonos units with an assortment of probes for both echocardiography and transabdominal imaging. One remains in the Zoo’s Animal Health Center and others are stored and used in animal areas for pregnancy diagnosis, echocardiograms on awake gorillas (through the mesh barrier), or just training/conditioning animals for awake ultrasound exams.

Zoo animals may present unique challenges when ultrasound imaging transcutaneously. In the case of fish and amphibians, imaging through a water bath (without even touching the patient!) can be very effective and noninvasive. The rough scaly skin of some reptiles makes a warm water bath similarly effective as a conductive medium for imaging snakes and lizards. Birds are not often examined via ultrasound because of the extensive respiratory (air sac) system they possess that interferes with the sound waves. For mammals, different species present different challenges. Many mammal species are thickly furred necessitating clipping of hair to establish good contact between the transducer and the skin. For transabdominal imaging, some species are very gassy (hippos, gorillas), which may complicate diagnostic imaging. Large or dangerous mammals that are examined awake via training need to be conditioned to present the body part of interest (chest, abdomen) at the barrier mesh and trust their trainer/keeper to allow contact with the probe. Often the greatest hurdle is habituating the animal to the ultrasound gel! When performing transabdominal imaging in our pregnant African elephant cow, rather than go through gallons of ultrasound gel smeared on her flank to fill in all the cracks and crevices in her thick skin, we run water from a hose just above wherever the transducer is placed.

DSC_4176

As general practitioners, zoo veterinarians have variable amounts of training in ultrasonography. We strive to do the best we can and are constantly learning, but the high variability in our daily tasks makes becoming an expert in ultrasound very difficult. So “it takes a village,” and we will regularly utilize specialists in our community to assist us in providing the best medical care for our patients. If I have a zebra or related species that requires a reproductive ultrasound exam, we will reach out to a local equine veterinarian that can apply their expertise in horses to a related species. Great apes have a high incidence of heart disease so whenever a gorilla or orangutan is anesthetized for an exam, part of the comprehensive care they receive is an echocardiogram by a human sonographer. Female great apes may get attention from our volunteer gynecologic sonographer as part of a reproductive evaluation. If the ultrasound exam is on a sea lion, wolf, or bear, I may contact a veterinary radiologist or veterinary internist competent in ultrasonography to assist.

In summary, ultrasonography represents a valuable, noninvasive, diagnostic tool for the zoo veterinarian.

Have you ever performed an ultrasound examination at a zoo? What was your experience? Comment below, or, AIUM members, continue the conversation on Connect, the AIUM’s online community. 

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Zoli Gyimesi, DVM, is the Senior Veterinarian at the Louisville Zoo in Louisville, Kentucky.

From Sonographer to Ultrasound Practitioner: My Career Journey

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I have been a sonographer for 18 years, and this year I was awarded Distinguished Sonographer at the 2018 AIUM Annual Convention. I can say without reservation that it is the biggest career honor that I have ever received and a moment that I will never forget. My path to becoming an Ultrasound Practitioner with a faculty appointment in the Department of Reproductive Medicine at UC San Diego has been rewarding, but it has not been easy. To be honest, I wasn’t always sure that I wanted to be a sonographer for more than a few years. I remember asking myself: Is this career as a sonographer enough or should I push myself further and go back to medical school? I have an incredible husband (who is also a sonographer) and he would have supported any choice I made, but ultimately – I decided not to pursue medical school. Even though I made that choice, I also told myself that there was nothing stopping me from learning as much as I could—my degree would not limit my potential and would not be what defines me.tantonheadshotblog

Since then, I have been studying the fetal heart A LOT. I enjoy all aspects of Maternal-Fetal Medicine (MFM) ultrasound, but the heart has always been an area of fascination for me. I love that it is both dynamic and complex, and, in my opinion, the most challenging aspect of fetal ultrasound. I have taken every opportunity to learn as much as I can from the incredible mentors that I have had the privilege of working with over the years. To this day, I am still learning, and I am amazed at all of the details we can see in these tiny little hearts! I eventually got the opportunity to cross train in pediatric echo and I jumped at that chance as well. I really enjoy being a part of a team of providers that can help the families affected by congenital heart disease.

I am, or I guess I should say I used to be, terrified of public speaking. I am proud of myself for overcoming this fear. Being in an academic center, I was used to teaching one on one, but it was about 8 years ago when I really pushed myself out of my comfort zone by lecturing to larger groups in the San Diego community. Putting together lectures can be time-consuming, difficult, and even stressful. I have spent many hours on weekends and evenings working on them, but I have also learned so much in the process. I started by speaking at local societies and hospitals, but over the years I have progressed and now I am proud to be invited to lecture at AIUM, SMFM, and other CME events around the country. Overcoming my fear of public speaking has been a huge stepping stone in my career and I love representing the sonographer voice on a larger platform.

So, how did I become a Practitioner with a faculty appointment?

I had a vision of how an Ultrasound Practitioner could function in our department. After all, by that point in my career, I was a seasoned MFM sonographer with 10 years of experience and I was still incredibly driven to learn and grow. I was keen to expand my skill set to function as a mid-level provider. Ultrasound Practitioner is not a new concept; SDMS had proposed a working model for an Ultrasound Practitioner in 2001. Dr. Beryl Benacerraf, among others, had already been successfully using an Ultrasound Practitioner for years. But working in a large academic center – my vision took years to bring to reality. I knew it would never happen if I didn’t continue to push for it. Along the way, I struggled, I questioned myself, I got overwhelmed, but I never gave up. I also had the support of some key physicians who believed in me. Their support was crucial to my eventual success.

I have now been an Ultrasound Practitioner for 6 years and as our department has grown to 8 ultrasound rooms, my role has expanded. Some of my responsibilities include: checking sonographers’ cases for quality and completeness, directing sonographers to get more images, obtaining images on difficult or complex cases, deeming the exam complete, writing preliminary reports, and discussing routine sonographic findings with patients. This working model frees up the physicians to spend more time with patients with abnormal findings and also allows the sonographers to keep moving with their schedules while ensuring quality patient care. Of course, this is only a snapshot of my day to day work, I still perform many of the fetal echocardiograms. I love to scan and I wouldn’t have it any other way.

My path to becoming a faculty member in the Department of Reproductive Medicine at UC San Diego was similar to my journey to becoming an Ultrasound Practitioner: it took time, lecturing nationally as well as teaching locally, coauthoring research papers and once again, having mentors who supported my appointment.

So, when people ask me about my success, I tell them it is because of hard work, persistence, believing in myself, and having mentors who believe in me too. My advice to sonographers is to know how important your role is; you are not “just a sonographer.” You should always keep learning, take pride in your work, and don’t be intimidated by the hierarchy of medicine. Our voice is crucial to the care of our patients, and that is really what matters.

Benacerraf BR, Bromley BS, Shipp TD, et al. The making of an advanced practice sonographer. J. Ultrasound Med 2003; 22:865–867.

Lockhart ME, Robbin ML, Berland LL, Smith JK, Canon CL, Stanley RJ. The sonographic practitioner: piece to the radiologist shortage puzzle. J Ultrasound in Med 2003; 22:861–864.

Bude RO, Fatchett AS, Lechtanski RT. The Use of Additionally Trained Sonographers as Ultrasound Practitioners. J Ultrasound Med 2006; 25:321–327

Society of Diagnostic Medical Sonography. Ultrasound Practitioner master’s degree curriculum and questionnaire: response by the SDMS membership. J Diagn Med Sonography 2001; 17:154–161.

How has ultrasound shaped your career? If you are an Ultrasound Practitioner, how did you get there? Comment below, or, AIUM members, continue the conversation on Connect, the AIUM’s online community. 

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Tracy Anton, BS, RDMS, RDCS, FAIUM, is an Ultrasound Practitioner with a faculty appointment in the Department of Reproductive Medicine at University of California, San Diego.

Determining Umbilical Cord Blood Flow

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Umbilical cord blood flow is among the most highly desired parameters for monitoring fetal well-being. This is because cord blood flow directly reflects placental volume flow, which is considered to be as important in the fetus as cardiac output and lung perfusion are in adults.1 Yet, presently employed noninvasive methods, such as umbilical artery Doppler waveform analyses, use surrogate flow evaluation parameters, such as systolic/diastolic ratios, which do not directly reflect placental-fetal blood flow.2,3 Volume flow estimation overcomes this by measuring true flow, and it has been shown that volume flow changes in the umbilical vein occur before umbilical artery flow indices become abnormal.4

Yet, the present volume flow measurement method has severe problems limiting its utility. These include technical difficulties in flow measurement in umbilical cords and faulty assumptions employed in the measurement. The present method using spectral Doppler is

                 Q = V × A                    (1),

where Q is volume flow, V is the mean velocity through the Doppler sample volume, and A is the cross-sectional area of the vessel of interest. This formula assumes that the 2D flow profile is cylindrically symmetric with a circular cross-section, and the line of the Doppler sampling cuts perfectly through the center of the sampled vessel. The velocity estimates require angle correction, and if the vessel is tortuous, as in umbilical cords, the sampling position placement and angle correction are hard to perform. Multiple investigators have warned that small errors in volume flow components can result in large errors in the calculation of volume flow.5-7

A new, easy-to-perform volume flow method overcomes almost all of the limitations of the standard technique. The new method is angle independent, flow profile independent, and vessel geometry independent. It works as follows:

Volume flow is defined as the total flux across any surface, S, intersecting the vessel. This is written as

Eq2

where Q is again volume flow, V is the local velocity through each area element dA, and “∙” is the dot product which projects the local velocity V onto the normal vector for each area element. This is known as Gauss’s theorem. The intersecting surface, known as the “C” surface, is very simple to obtain using 3D ultrasound (Figure8). In order to validate this method, we obtained an AIUM EER-funded research grant.

Fig

Figure: (A) Four-panel view of a single 3D color flow acquisition of the umbilical cord. The four views are as follows: upper-left is axial-lateral, upper-right is axial-elevational, bottom-left is elevational-lateral (ie, the c-surface), and bottom-right is a rendered 3D reconstruction. Arteries are shown in blue and the vein is shown in red. The schematic in (B) illustrates the orientation of the probe and the corresponding c-surface in the elevational-lateral imaging plane. The vessel colors in (B) match the directionality in (A). The entire umbilical cord passes through the c-surface but only the cross-sections of the umbilical arteries and umbilical vein are illustrated in (B). The two arteries are separated in power Doppler (not shown). (Printed with permission from Pinter et al. J Ultrasound Med. 2012;31(12):1927-34. © 2016 by the American Institute of Ultrasound in Medicine)

We had 2 specific aims: 1) Test the reproducibility of the volume flow measurement, and 2) evaluate the relationship of volume flow to clinical outcome in a high-risk patient population.

In the first aim, we performed studies on 35 subjects between the gestational ages of 22–37 weeks, 26 high risk and 9 normal.9 We attempted to measure umbilical cord blood flow at 3 sites in the cord in each subject, and we averaged 28.3 ± 3.3 (mean ± standard deviation) samples per site. We used a GE LOGIQ E9 ultrasound system with a 2.0–8.0 MHz bandwidth convex array transducer to acquire multiple volume 3D color and power mode data sets. Since we were measuring mean blood flow, we assessed variability using relative standard error (standard error /mean) (RSE). The average RSE for blood flow at each cord position was ±5.6% while the average RSE among the measurements in each subject was ±12.1%.

For the second aim, we compared the volume flow measurements in 5 subjects that developed preeclampsia with the 9 normal subjects. Even with these small numbers, we detected a significant difference between the mean depth-corrected, weight-normalized umbilical vein blood volume flows in the two groups (P = .035). Further, blood flow abnormalities were detected either at the same time or preceded the hypertensive disorder in 4 of the 5 subjects. This is consistent with our prior publication where blood flow changes preceded the onset of pre-eclamptic symptoms in a study subject.8

With the introduction of 2D array transducers, umbilical cord volume flow estimates can be performed in seconds and given the valuable information provided by this method, umbilical cord volume flow will hopefully become a standard component of fetal examinations.

References:

  1. Tchirikov M, Rybadowski C, Huneke B, Schoder V, Schroder HJ. Umbilical vein blood volume flow rate and umbilical artery pulsatility as ‘venous-arterial index’ in the prediction of neonatal compromise. Ultrasound Obstet Gynecol. 2002;20:580-5.
  2. Newnham JP, Patterson LL, James IR, Diepeveen DA, Reid SE. An evaluation of the efficacy of Doppler flow velocity waveform analysis as a screening test in pregnancy. Am J Obstet Gynecol. 1990;162:403-10.
  3. Acharya G, Wilsgaard T, Bernsten GKR, Maltau JM, Kiserud T. Doppler-derived umbilical artery absolute velocities and their relationship to fetoplacental volume blood flow: a longitudinal study. Ultrasound Obstet Gynecol. 2005;25:444-53.
  4. Rigano S, Bozzo M, Ferrazzi E, Bellotti M, Battaglia FC, Galan HL. Early and persistent reduction in umbilical vein blood flow in the growth-restricted fetus: a longitudinal study. Am J Obstet Gynecol. 2001;185:834-8.
  5. Evans DH. On the measurement of the mean velocity of blood flow over the cardiac cycle using Doppler ultrasound. Ultrasound Med Biol. 1985;11(5):735-41.
  6. Gill R. Measurement of blood flow by ultrasound: accuracy and sources of error. Ultrasound Med Biol. 1985;11:625-41.
  7. Lees C, Albaiges G, Deane C, Parra M, Nicolaides KH. Assessment of umbilical arterial and venous flow using color Doppler. Ultrasound Obstet Gynecol. 1999;14:250-5.
  8. Pinter SZ, Rubin JM, Kripfgans OD, Treadwell MC, Romero VC, Richards MS, Zhang M, Hall AL, Fowlkes JB. Three-dimensional sonographic measurement of blood volume flow in the umbilical cord. J Ultrasound Med. 2012;31(12):1927-34.
  9. Pinter SZ, Kripfgans OD, Treadwell MC, Kneitel AW, Fowlkes JB, Rubin JM. Evaluation of umbilical vein blood volume flow in preeclampsia by angle-independent 3D sonography [published online ahead of print December 15, 2017]. J Ultrasound Med. doi:10.1002/jum.14507.

How do you determine umbilical cord blood flow? What problems have you encountered using the traditional method? Comment below or let us know on Twitter: @AIUM_Ultrasound.

Jonathan Rubin, MD, PhD, FAIUM, is Professor Emeritus of Radiology at University of Michigan.

Dating Pearls

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Assisted reproductive technology (ART) dating trumps all other sonographic dating. If the dating is off with ART, think about asking if the embryo was put in the uterus at 5 days, and not zero days, as that is how it is often calculated. This can be important if the embryo is larger than expected, as ART pregnancies have an increased incidence of Beckwith Weidman Syndrome, which is an overgrowth syndrome. If the embryo is smaller than expected, then the embryo should be followed more closely for possible congenital or chromosomal anomalies.

If the pregnancy is not ART, dating should be based on the 2014 ACOG/AIUM Committee Recommendations (Methods for Estimating the Due Date. Committee Opinion No, 700. American College of Obstetricians and Gynecologists. Obstet Gynecol 2017; 129:e150–154).

Measurement of the embryo or fetus in the first trimester is the most accurate method to determine gestational age. In the first trimester, the 2014 Recommendations state that if the pregnancy is less than 8 weeks 6 days, the embryo should be within 5 days of LMP (last menstrual period) and otherwise should be re-dated using ultrasound dates of the crown rump length. One mistake often made at this time is to include the gestational sac size in dating; the crown rump length is more accurate than the sac size and thus it should not be averaged into the estimated gestational age.

Crown rump length growth curves have been updated by Pexsters et al (Ultrasound Obstet Gynecol 2010; 35:650–655) using 4387 exams, whereas Hadlocks curves (Hadlock et al Radiology 1992; 182:501–505) were only based on 416 exams. These have some significant discrepancies in the 5–7 weeks gestational age range so we recommend using the Pexsters curves.

Crown Lump Length

From 9 weeks to 16 weeks 6 days, the 2014 Recommendations suggest that the dating should be within 7 days and be re-dated if greater than “7-day” discrepancy.

From 16 weeks to 21 weeks 6 days, the 2014 Recommendations suggest that the dating should be within 10 days and be re-dated if greater than “10-day” discrepancy.

From 22 weeks to 27 weeks 6 days, the 2014 Recommendations suggest that the dating should be within 14 days and be re-dated if greater than “14-day” discrepancy.

From 28 weeks and beyond, the 2014 Recommendations suggest that the dating should be within 21 days and be re-dated if greater than “21-day” discrepancy.

We should not re-date a pregnancy in the second or third trimester if there are good ultrasound dates in the first trimester. If the patient gives “excellent dates” based on history (eg keeping a temperature chart, knowing date of conception based on specific dates of being with partner) and there is a greater than expected discrepancy of dates, then a follow-up sonogram should be recommended in 2–4 weeks, depending on the time of gestation (4 weeks in the second trimester and 2 weeks in the third trimester) so that appropriate growth can be assessed.

Serial growth is important in assessing dating. A fetus that grows 4 weeks in a 4-week period is likely dated appropriately. When the fetus grows more than 4 weeks in a 4-week period then accelerated growth should be reported, suggesting either an LGA (large for gestational age) or macrosomic fetus. History of prior pregnancies can be particularly helpful in these cases. Placement of the calipers at the outer edge of the subcutaneous tissue is particularly important in these cases. We often require 3 measurements, which are averaged to assess LGA/macrosomic fetuses.

When fetuses grow less than 4 weeks in a 4-week period then SGA (small for gestational age) or IUGR (intrauterine growth restriction) are suspected. Additional studies for well-being should be performed, such as umbilical artery Doppler, middle cerebral artery Doppler, maximum vertical pocket of amniotic fluid, biophysical profile, cerebroplacental ratio (CPR), or antenatal testing.

Do you have any tips on sonographic dating? Comment below or let us know on Twitter: @AIUM_Ultrasound.

Dolores H. Pretorius, MD, is a Professor of Radiology at University of California, San Diego, and Director of Imaging at UC San Diego Maternal-Fetal Care and Genetics, an AIUM-accredited practice.

Andrew D. Hull, MD, is a Professor of Clinical Reproductive Medicine at University of California, San Diego, and Director of UC San Diego Maternal-Fetal Care and Genetics, an AIUM-accredited practice.

Do You Allow Patients to Video?

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An expecting new mother comes into your practice for a routine ultrasound exam. During the exam she pulls out her cell phone to capture a few photos and maybe a short video. What do you do?

As cell phone use has become ubiquitous, the AIUM has been receiving more and more calls and messages asking about cell phone use policies during obstetric exams. Practices are searching for guidance on how to set such a policy and what should be included.

To get a sense of how practices are dealing with this issue, last month, the AIUM sent a short survey to 1,652 individuals in 1,138 AIUM OB-accredited practices. Nearly 22% of recipients completed the survey.

video

Allow patients to record exams?

According to the results, 88% said their practice does not allow videotaping during OB exams. However, only 51% said their practice has a written policy that supports this.

Why Have a Policy?
Those practices that forbid or restrict videotaping do so for a number of reasons. Some of the most commonly cited reasons include:

policy

Written policy in place?

  • It is distracting. Several respondents mentioned that having people videotaping is very distracting to the sonographers and physicians who are trying to conduct a medical examination. To help these individuals focus on medical care, videotaping is not allowed.
  • Legality. In order to protect the patient’s medical information and staff identity, practices do not allow videotaping.
  • Findings. When a sonographer or physician begins an examination, they do not know what they might find. To avoid the widespread sharing of unread studies or potentially personal information or decisions, practices ask that patients keep their phones off.

Enforcement
While nearly half of AIUM-accredited practices stated they do not have a written policy, there are several ways in which patients are told or asked to refrain from videotaping. Those methods include:

  • Information in new patient packages
  • Signs posted throughout the practice: waiting rooms, exam rooms, on the ultrasound machines
  • Verbal statements from sonographers and physicians

Even using these methods, survey respondents acknowledge that enforcement is difficult because people still pull out their phones and hit record. Some practices do empower their employees by allowing them to stop the exam should a visitor not comply with the videotaping rules.

When Is It OK?
Of those practices that allow videotaping, most have rules about when and how it is allowed.

  • Some practices allow short videos showing certain anatomy.
  • Others state that patients can’t videotape staff or require that staff stay silent when patients are videotaping.
  • In some practices, the sonographers and physicians use their discretion to control when and for how long videotaping can occur.
  • Others allow unlimited videotaping after the diagnostic portion of the exam.
  • Some practices will allow FaceTime (non-permanent) video during the exam but prohibit permanent videotaping.
  • And still others are completely open and allow the entire exam to be videotaped.

Even among those practices that forbid videotaping, some may be allowed. The typical exceptions are for deployed parents or foreign parents of a surrogate. Many practices mentioned that they try to avoid the videotaping issue altogether by stating their policy and then following that by telling the patient they will supply some pictures or short video clips.

What can you do?
If your practice is looking to set a policy or even seeking resources to support your policy, here are some items that might help.

  • Legal Counsel—If you are concerned about the legal aspect of allowing videotaping, or you are looking to set an official policy, seek legal advice and counsel.
  • AIUM’s Keepsake Imaging Official Statement—This resource may help you in framing your policy, and it serves as a great document to share with patients.
  • HIPAA—Several practices mentioned HIPAA compliance in their policies or statements as a reason for not allowing the use of videotaping during exams.
  • Consent Law—In setting your policy, you may have support through your state’s consent laws.

In most cases, obstetric patients are not videotaping with ill intent. But as physicians and sonographers, there are legitimate and medical reasons to consider whether your practice should institute a policy on the use of videotaping equipment. While it can be a challenge to balance legal liability, best practice guidelines, and customer service, working with your staff, your legal counsel, and your customers, you can create a policy that works for all.