Tag Archives: obstetric

Ultrasound: How to respond to questions about its safety

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“Is ultrasound safe for my baby?” and “I know someone whose baby was born too small because of all the ultrasound she received during her pregnancy”. These are two sentences that you might hear during your busy day in the ultrasound unit. The AIUM Official Statement “Conclusions Regarding Epidemiology for Obstetric Ultrasound” states: “Based on the available epidemiologic data, there is insufficient justification to warrant conclusion of a causal relationship between diagnostic ultrasound and recognized adverse effects in humans. The epidemiologic evidence is based primarily on exposure conditions existing prior to 1992, the year in which maximum recommended levels of acoustic output for ultrasound machines were substantially increased for fetal/obstetric applications. Some older studies have reported effects of exposure to diagnostic ultrasound during pregnancy, such as low birth weight, delayed speech, dyslexia, and non-right-handedness. Other more recent studies have not demonstrated such effects. The absence of definitive epidemiologic evidence does not preclude the possibility of adverse effects of ultrasound in humans.”

Why is this statement important to all practitioners of ObGyn ultrasound?

Because knowing the information will enable you to answer patient questions and comments mentioned at the beginning of this post. What the AIUM statement explains is that studies performed on specific large human populations, with defined methods did not show that diagnostic ultrasound is responsible for harm in humans. (Studies such as this are what epidemiology does: examine how often diseases occur in different groups of people and why.)

While in the past, there were some publications that suggested some effects, such as low birth weight, more controlled studies have not been able to demonstrate such effects in humans. An important point is that many studies are relatively old and were performed before maximum recommended output of ultrasound machines meant for OB use was increased from 94mW/cm2 to 720mW/cm2.  This increase was intended to obtain more detailed images. The US Food and Drug Administration (USFDA) agreed with ultrasound instrument manufacturers’ requests to allow this increase, on the condition that two numbers were displayed in real-time on the monitor of the ultrasound system:

  • The thermal index (TI) to show the possibility of increased temperature, secondary to energy absorption by the tissues, and
  • The mechanical index (MI) to convey the risk of direct effects of the sound waves.

If these are kept low, no noxious effects are demonstrable, as expressed in the Epidemiology statement. This includes physical as well as mental effects. What are low indices? If the TI is <1 (the scientific number is 0.7, but 1 is easier to remember), there appears to be no risk of thermal effects for exposure under 1 hour. Regarding non-thermal or mechanical effects, based on the absence of gas bubbles in the fetal lungs and bowels (the two organs where effects were shown in animals after birth), no effects are expected in human fetuses. Demonstrating long-term effects or lack thereof, particularly if subtle, is much more complicated.

The statements issued by the AIUM’s Bioeffects Committee are intended as baseline considerations in practice. As ultrasound continues to be adopted into clinical use, the Bioeffects Committee will continue to monitor outcomes in order to inform and educate the community.

Jacques S. Abramowicz, MD, is a professor in the Department of Obstetrics and Gynecology at the University of Chicago.

Interested in learning more about the bioeffects of ultrasound? Check out the following AIUM Official Statements:

Also:

Abramowicz JS, Fowlkes JB, Stratmeyer ME, Ziskin MC. Bioeffects and Safety of Fetal Ultrasound Exposure: Why do we Need Epidemiology? In: Sheiner E, (ed.): Textbook of Epidemiology in Perinatology. New York: Nova Science Publishers, Inc.; 2010.

Ultrasound to Differentiate Benign From Malignant Ovarian Tumors—Are We There Yet?

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Adnexal (ovarian) tumors present a complex problem. Ovarian cancer (Ovca) is the second most common gynecologic cancer in the United States with the highest mortality rate of all gynecologic cancer, 7th among all cancers, and with a general survival rate of 50%.1 Thus, missing Ovca when performing any kind of test (false negative) will have grave consequences but suspecting it when not present (false positive) can have almost as critical results with morbidity and mortality secondary to (unnecessary) intervention.

The purpose of this post is not to review the differential diagnosis of ovarian tumors nor to discuss chemical markers such as CA125 or cancer-specific signal found on cell-free DNA (cfDNA) but to concentrate on ultrasound. Some tumors are relatively easy to recognize because of defined ultrasound characteristics: corpus luteum with the classic “ring of fire” or endometrioma with the ground-glass appearance content, for instance (image 1a and b). Conversely, a large, multilocular lesion with solid components and profuse internal Doppler blood flow leaves little doubt about its malignant nature (image 2).

Image 1a: Corpus luteum with the classic
“ring of fire”.
Image 1b: Endometrioma with the
ground-glass appearance.
Image 2: A large, multilocular lesion with solid components.

What are the ultrasound characteristics we look at?

  1. Size: Unilocular cystic ovarian tumor < 10 cm in diameter or simple septated cystic ovarian tumor < 10 cm in diameter rarely, if ever, are neoplastic.2
  2. Volume: Normal volume for premenopausal and postmenopausal ovaries are < 20 cm3 and 10 cm3, respectively.
  3. Appearance: Risk of malignancy in simple, unilocular anechoic cyst, less than 5 cm is < 1% in premenopause and about 2.8% in postmenopause.3
  4. Blood flow criteria: The rationale is that arteries formed by neovascularization in malignant tumors lack tunica media, resulting in lowered impedance (= less resistance to blood flow). Thus, resistance indices will be lower in cancer than in benign tumors. Malignancy was suspected with Doppler indices: pulsatility index (PI)<1 and/or resistive index (RI)<0.4.4 However, too much overlap makes reliance on only Doppler unjustified.

A very important point is that the expert performs very well when analyzing the ultrasound images of an ovarian mass, with a sensitivity of 92–98% and a specificity of 89%. The issue is how to help the non-expert decide whether he/she can continue the care of the patient or needs to refer her to a specialist. Based on several ultrasound criteria, scoring systems were implemented. The first one, in 1990, included appearance (unilocular, unilocular solid, multilocular, multilocular solid, or solid cyst) and presence of papillae (graded according to their number: 0 [none], 1 [one to five], or 2 [more than five]). This method had a sensitivity (true positive rate, or chance that person testing positive actually has Ovca) for malignancy of 82% with a specificity (true negative rate or chance that person with a negative test does not have Ovca) of 92%.5 Two important additional scoring systems were described later: the Morphology Index (MI) combining tumor volume, wall structure, and septal structure and the Risk of Malignancy Index (RMI), the product of ultrasound morphology score, CA 125 level, and menopausal status.6 Additional systems included the Logistic Regression 1 (LR1) and 2 (LR2). None of the published scoring systems were superior to image assessment by an expert, including in a meta-analysis of 47 articles, including over 19000 adnexal masses7 and, in reality, were not used widely in clinical practice.

The International Ovarian Tumor Analysis (IOTA) models

In 2000, a large group of European experts (gynecologists, radiologists, statisticians, biology, and computer experts) published a standardized terminology for the characterization of adnexal masses.8

The two important systems are the Simple Rules (SR) and the Assessment of Different NEoplasias in the adneXa (ADNEX) model. These were externally validated in numerous centers across the world but not in the USA.9 Recently, however, validation on the largest hitherto US population was published.10 This study showed for the first time that the models were effective in this population, regardless of menopausal status or race. These models are easy to learn and are geared towards non-experts.11 It is important to note that the IOTA group was one of the first to incorporate acoustic shadow as a key feature, and the acoustic shadow has been shown to be an important sonographic feature to consider.12

  1. Simple Rules: The IOTA Simple-Rules consist of 2 sets of 5 elements each: benign and malignant.13 Three simple rules are applied: if only benign characteristics are present, the mass is classified as benign. If only malignant features are present, the mass is considered malignant. If no features or both are, the findings are inconclusive. This model works well in about 80% of cases. The other 20% should be referred to an expert.
  2. ADNEX model14: This is a multiclass prediction model to differentiate between benign and malignant tumors and allows automatic calculation of sub-classification of malignant tumors into borderline tumors, Stage I, and Stage II–IV primary cancers, and secondary metastatic tumors. “The advantage of this model is that it gives a personalized risk score for each patient, based on age, whether the patient is seen at an oncology center or not, maximal diameters of the lesion and the solid parts, number of cysts and papillary projections, whether acoustic shadows are present, whether ascites is present and CA125 value (if available, not mandatory for calculation). With a cut-off value for malignancy risk set at 10%, the ADNEX model (with CA125) had a sensitivity of 94.3%, with a specificity of 74%, positive predictive value of 76%, and negative predictive value of 93.6%.”14

The O-RADS model

In 2020, the American College of Radiology convened an international multidisciplinary committee that developed an ultrasound model based on an MRI model used in mammography (the BI-RADS atlas), the O-RADS model (the Ovarian-Adnexal Reporting and Data System) to facilitate differentiation between benign and malignant ovarian tumors.15 It relies on the sonographic nomenclature developed by the IOTA group, but it classifies tumors into 1 of 6 categories (O-RADS 0–5), from normal to high risk of malignancy. O-RADS also includes guidelines for the management of the findings. It should be noted that the O-RADS first model did not take into account the presence or absence of an acoustic shadow, although this has now been amended.

A description of the most recent common ultrasound scoring systems (SR, ADNEX, and O-RADS) is available in the Journal of Ultrasound in Medicine (JUM): Yoeli-Bik R, Lengyel E, Mills KA, Abramowicz JS. Ovarian masses: The value of acoustic shadowing on ultrasound examination. J Ultrasound Med 2023; 42:935–945.    

References

  1. https://www.cancer.org/cancer/types/ovarian-cancer/about/key-statistics.html
  2. Saunders et al. Risk of malignancy in sonographically confirmed septated cystic ovarian tumors. Gynecol Oncol 2010; 118:278–282.
  3. Valentin et al. Risk of malignancy in unilocular cysts: a study of 1148 adnexal masses classified as unilocular cysts at transvaginal ultrasound and review of the literature. Ultrasound Obstet Gynecol 2013; 41:80–89.
  4. Bourne et al. Transvaginal colour flow imaging: a possible new screening technique for ovarian cancer. BMJ 1989; 299:1367–370.
  5. Granberg S et al. Tumors in the lower pelvis as imaged by vaginal sonography. Gynecol Oncol 1990; 37: 224–229.
  6. Yamamoto Y, Yamada R, Oguri H, Maeda N, Fukaya T. Comparison of four malignancy risk indices in the preoperative evaluation of patients with pelvic masses. Eur J Obstet Gynecol Reprod Biol 2009; 144:163–167.
  7. Meys EM et al. Subjective assessment versus ultrasound models to diagnose ovarian cancer: A systematic review and meta-analysis. Eur J Cancer 2016; 58:17–29.
  8. Timmerman D, Van Calster B, Testa A, et al. Predicting the risk of malignancy in adnexal masses based on the simple rules from the international ovarian tumor analysis group. Am J Obstet Gynecol 2016; 214:424–437.
  9. Abramowicz JS, Timmerman D. Ovarian mass-differentiating benign from malignant: the value of the International Ovarian Tumor Analysis ultrasound rules. Am J Obstet Gynecol 2017; 217:652–660.
  10. Yoeli-Bik R, Longman RE, Wroblewski K, Weigert M, Abramowicz JS, Lengyel E. Diagnostic performance of ultrasonography-based risk models in differentiating between benign and malignant ovarian tumors in a US cohort. JAMA Netw Open 2023; 6:e2323289.
  11. Valentin L, Ameye L, Jurkovic D, et al. Which extrauterine pelvic masses are difficult to correctly classify as benign or malignant on the basis of ultrasound findings and is there a way of making a correct diagnosis? Ultrasound Obstet Gynecol 2006; 27:438–444.
  12. Yoeli-Bik R, Lengyel E, Mills KA, Abramowicz JS. Ovarian masses: The value of acoustic shadowing on ultrasound examination. J Ultrasound Med 2023; 42:935–945.
  13. Timmerman D, Testa AC, Bourne T, et al. Simple ultrasound-based rules for the diagnosis of ovarian cancer. Ultrasound Obstet Gynecol 2008; 31:681–90.
  14. Van Calster B, et al. Evaluating the risk of ovarian cancer before surgery using the ADNEX model to differentiate between benign, borderline, early and advanced stage invasive, and secondary metastatic tumours: prospective multicentre diagnostic study. BMJ 2014; 349:g5920.
  15. Andreotti RF, Timmerman D, Strachowski LM, et al. O-RADS US risk stratification and management system: a consensus guide-line from the ACR ovarian-adnexal reporting and data system committee. Radiology 2020; 294:168–185.

Appendix

Classification of primary ovarian tumors

  1. Ovulatory: functional or corpus luteum cyst; theca lutein cyst; polycystic ovary
  2. Infectious or inflammatory: tubo-ovarian abscess; hydrosalpinx
  3. Benign: serous or mucinous cystadenoma; endometrioma; mature cystic teratoma (most common primary benign tumor of the ovary); paraovarian/paratubal cysts
  4. Borderline: serous, mucinous
  5. Malignant
  6. Epithelial: high-grade serous carcinoma (HGSC; 70 to 80%); endometrioid carcinoma (10%); clear cell carcinomas (10%); mucinous carcinoma (3%); Low-grade serous carcinoma (LGSC; <5%); Brenner tumor; carcinosarcoma or malignant mixed müllerian tumor (MMMT); undifferentiated,
  7. Germ cell (20%): teratoma: immature, specialized teratomas of the ovary (struma ovarii, carcinoid tumor); dysgerminoma; yolk sac tumor: endodermal sinus tumor; embryonal carcinoma; choriocarcinoma: <1% of ovarian tumors; malignant mixed germ cell tumor
  8. Sex cord / stromal ovarian tumors (8–10%): fibrothecoma (fibroma, thecoma); Sertoli-Leydig cell tumor; granulosa cell tumor (juvenile or adult); small cell carcinoma

Jacques S. Abramowicz, MD, is a professor in the Department of Obstetrics and Gynecology at the University of Chicago.

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

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.

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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.