SonoStudy: Is Pelvic Ultrasound necessary after negative CT in non-pregnant women? #FOAMed

In the July 2013 issue of Clinical Radiology, the authors from Harvard Medical School review 126 patient charts of non-pregnant women who had a negative abdominal/pelvic CT from 2005- 2010 who then had a pelvic ultrasound for pelvic pain. Despite the obvious question, which is “why did they get a CT and not an ultrasound in the first place?” which will not be discussed, their findings were surprising. Im not sure why, but I guess it goes to show how good multi-detector CT imaging is for these patients now. This raises the question whether a pelvic ultrasound is needed in these patients given the low yield. It would be nice if this was a multi-site study with thousands of patients to increase the power, but the numbers here cannot be ignored. Below is the abstract:

AIM:

To determine the diagnostic value of pelvic ultrasound following negative abdominal/pelvic computed tomography (CT) in women presenting to the emergency room (ER) with abdominal/pelvic pain, and whether ultrasound altered clinical management in the acute-care setting.

MATERIALS AND METHODS:

Between January 2005 to October 2010, 126 consecutive, non-pregnant women with abdominal/pelvic pain underwent pelvic ultrasound within 24 h following negative abdominal/pelvic CT in the ER. Imaging findings/reports for the CT and ultrasound examinations, and clinical data/outcomes were recorded. The time interval between the CT and ultrasound examinations was calculated. Mean length of stay (LOS) was compared to that of age-matched controls who did not have subsequent ultrasound using the t-test.

RESULTS:

Only 3% (four of 126 cases) of the pelvic ultrasound examinations showed positive findings, all of which were endometrial abnormalities. One patient was diagnosed with an endometrial polyp, whereas the others were lost to follow-up. In none of the four cases was the pelvic ultrasound finding relevant to the acute presentation or altered acute care. The average time between CT to ultrasound was 3 h and 4 min. Mean LOS was 22 h and 13 min for the cohort, and 16 h and 8 min for the age-matched controls, although this was not statistically significant (p = 0.29).

CONCLUSION:

Immediate ultrasound re-imaging of the pelvis following negative CT in women with acute abdominal/pelvic pain yields no additional diagnostic information and does not alter acute care.

 

A similar study was done and published in 2011 out of NYU – abstract below:

Abstract

To determine the added value of reimaging the female pelvis with ultrasound (US) immediately following multidetector CT (MDCT) in the emergent setting. CT and US exams of 70 patients who underwent MDCT for evaluation of abdominal/pelvic pain followed by pelvic ultrasound within 48 h were retrospectively reviewed by three readers. Initially, only the CT images were reviewed followed by evaluation of CT images in conjunction with US images. Diagnostic confidence was recorded for each reading and an exact Wilcoxon signed rank test was performed to compare the two. Changes in diagnosis based on combined CT and US readings versus CT readings alone were identified. Confidence intervals (95%) were derived for the percentage of times US reimaging can be expected to lead to a change in diagnosis relative to the diagnosis based on CT interpretation alone. Ultrasound changed the diagnosis for the ovaries/adnexa 8.1% of the time (three reader average); the majority being cases of a suspected CT abnormality found to be normal on US. Ultrasound changed the diagnosis for the uterus 11.9% of the time (three reader average); the majority related to the endometrial canal. The 95% confidence intervals for the ovaries/adnexa and uterus were 5-12.5% and 8-17%, respectively. Ten cases of a normal CT were followed by a normal US with 100% agreement across all three readers. Experienced readers correctly diagnosed ruptured ovarian cysts and tubo-ovarian abscesses (TOA) based on CT alone with 100% agreement. US reimaging after MDCT of the abdomen and pelvis is not helpful: (1) following a normal CT of the pelvic organs or (2) when CT findings are diagnostic and/or characteristic of certain entities such as ruptured cysts and TOA. Reimaging with ultrasound is warranted for (1) less-experienced readers to improve diagnostic confidence or when CT findings are not definitive, (2) further evaluation of suspected endometrial abnormalities. A distinction should be made between the need for immediate vs. follow-up imaging with US after CT.
One reason for reviewing this is that women may feel uncomfortable with this procedure. Recently there was a lawsuit filed stating a transvaginal US felt like “rape” – take care in your technique. I dont know any specifics of the case, but saw the news report and hoping more info comes.

SonoStudy and Review: The Beta hCG, the Ectopic, and the Ultrasound Findings – do they correlate?

In a recent article in the Journal of Ultrasound in Medicine (through AIUM), a study was done that illustrates exactly what we all experience in practice – an ectopic pregnancy can occur at any beta hCG level….AND a normal pregnancy can result despite a higher bHCG and no IUP seen. The conversations with the radiologists who still believe in “screening” who should and should not be scanned based solely on the beta hCG level will minimize – so we hope. The lowest beta hcg I have ever seen with a diagnosed ectopic? Brace yourselves…….152 ! There have been other case reports and cohort multi-site studies that you can read herehere, here, and here about low hCG and diagnosis of ectopic pregnancy. ACEP even has an article on it. But what if the beta hCG is high? …and you see nothing in the uterus on your ultrasound? There was a study done in 2011 by Wang, et al out of UCSF that discussed this too, asking if we should increase the discriminatory zone. There are also studies that show if you DO see something in the uterus, what does that mean in relation to ectopic pregnancy? Well, first, let’s talk physiology – Now, hCG is made by the syncytiotrophoblasts of the placenta after fertilization occurs, and correlates with the size and developing of the fetus…. well, Im going to stop there, as the only reason I stated that was to type “syncytiotrophoblasts” as I rarely have the opportunity to do so (insert sarcasm).

There is, however, a term used to describe the maternal serum hCG level above which a gestational sac should be consistently visible on transvaginal sonography – “discriminatory zone” – coined in the 1980s (yup, that’s right, 30 years ago!). This was thought to be 1,000, 1,500, or 2,000 on transvaginal ultrasound (and 3,600 or 6,000 on transabdominal ultrasound) depending on the study you read. So, if the hCG is above that zone and no IUP is seen – then you have yourself an ectopic pregnancy ….until proven otherwise! – and doctors would think treating for ectopic is the appropriate next step. Then there was a hiccup – There was a study that showed an HCG of 2,000 may not mean ectopic as 33% of the study’s subjects had a normal IUP after having no IUP on ultrasound when they were above that discriminatory zone. Oopsy! But, the prior studies all kinda had a possible gestational sac, but defined an IUP as the presence of a double decidua sign or yolks sac. So, this study wanted to know if there was no gestational sac and the bHCG was above this discriminatory zone, will there be an IUP, and if so, then what is the prognosis – in other words, is this discriminatory zone be valid?

“Objectives—The human chorionic gonadotropin (hCG) discriminatory level—the maternal serum β-hCG level above which a gestational sac should be consistently visible on sonography in a normal pregnancy—has been reported to be 1000 to 2000 mIU/mL for transvaginal sonography. We assessed whether a woman with a β-hCG above 2000 mIU/mL and no intrauterine fluid collection on transvaginal sonography can subsequently be found to have a live intrauterine gestation and, if so, what the prognosis is for the pregnancy.

 Methods—We identified all women scanned between January 1, 2000, and December 31, 2010, who met the following criteria: serum β-hCG testing and transvaginal sonography were performed on the same day; β-hCG was positive and sonography showed no intrauterine fluid collection; and a live intrauterine pregnancy was subsequently documented. We tabulated the β-hCG levels in these cases and assessed pregnancy outcome.

Results—A total of 202 patients met the inclusion criteria, including 162 (80.2%) who had β-hCG levels below 1000 mIU/mL on the day of the initial scan showing no intrauterine fluid collection, 19 (9.4%) with levels of 1000 to 1499, 12 (5.9%) 1500 to 1999, and 9 (4.5%) above 2000 mIU/mL. There was no significant relationship between initial β-hCG level and either first-trimester outcome or final pregnancy outcome (P> .05, logistic regression analysis and Fisher exact test). The highest β-hCG was 6567 mIU/mL, and the highest value that preceded a liveborn term baby was 4336 mIU/mL.

[Also: "Comparing outcomes in cases with β-hCG below 1000 versus above 1000 mIU/mL also showed no significant difference: 89.9% (125 of 139) live at the end of the first trimester in the low hCG group versus 88.6% (31 of 35) live in the high hCG group; 86.6% (110 of 127) liveborn in the low hCG group versus 80.6% (25 of 31) liveborn in the high hCG group (P > .05 for both comparisons Fisher exact test)]“

Conclusions—The hCG discriminatory level should not be used to determine the management of a hemodynamically stable patient with suspected ectopic pregnancy, if sonography demonstrates no findings of intrauterine or ectopic pregnancy.

 A great discussion on this also heard here BroomeDocs’ Casey Parker: here

For a great 5 minute talk on Ectopic pregnancy and how to identify it by ultrasound, see Dr. Phil Perera’s Soundbytes insert – but, as the studies above suggest, if you see no IUP despite an hCG above the discriminatory zone, there may not be an ectopic pregnancy – make sure to look around the adnexal region, and have close follow up with the Ob/Gyn doctor.

SonoStudy: Emergency Physicians can estimate gestational age in 1st trimester pregnancies

I recently posted about how emergency physicians can decrease the length of stay of patients with first trimester vaginal bleeding/pelvic pain (ruling out ectopic pregnancy) by performing a bedside pelvic ultrasound, which also had a couple cases to ponder about. As emergency physicians are getting more and more savvy with bedside ultrasound, it may benefit the patient’s future care if we are also able to tell them the gestational age. Well, this study (and great review) on emergency physicians-performed ultrasound estimating gestational age (compared with radiology results) highlights exactly that! And, guess what? we CAN estimate gestational age – shocking, I know. Below is the abstract:

ABSTRACT:

BACKGROUND: Patient reported menstrual history, physician clinical evaluation, and ultrasonography are used to determine gestational age in the pregnant female. Previous studies have shown that pregnancy dating by last menstrual period (LMP) and physical examination findings can be inaccurate. Radiology department ultrasound has proven to be the most accurate way of determining gestational age. The aim of this study is to determine the accuracy of emergency department ultrasound as an estimation of gestational age (EDUGA) in an emergency department (ED) population.

METHODS:

A prospective convenience sample of ED patients presenting in the first trimester of pregnancy (based upon self-reported LMP) regardless of their presenting complaint were enrolled. EDUGA was compared to gestational age estimated by ultrasound performed in the department of radiology (RGA) as the gold standard. Pearson’s product moment correlation coefficient was used to determine the correlation between EDUGA compared to RGA.

RESULTS:

Sixty-eight pregnant patients presumed to be in the 1st trimester of pregnancy based upon self-reported LMP consented to enrollment. When excluding the cases with no fetal pole, the median discrepancy of EDUGA versus RGA was 2 days (interquartile range (IQR) 1 to 3.25). The correlation coefficient of EDUGA with RGA was 0.978. When including the six cases without a fetal pole in the data analysis, the median discrepancy of EDUGA compared with RGA was 3 days (IQR 1 to 4). The correlation coefficient of EDUGA with RGA was 0.945.

CONCLUSION:

Based on our comparison of EDUGA to RGA in patients presenting to the ED in the first trimester of pregnancy, we conclude that emergency physicians are capable of accurately performing this measurement. Emergency physicians should consider using ultrasound to estimate gestational age as it may be useful for the future care of that pregnant patient.

SonoStudy: Bedside Pelvic Ultrasound decreases length of stay in the emergency department

In a recent study in Pediatric Emergency Care, the folks at newark Beth Israel in New Jersey studied whether performing a pelvic ultrasound decreases length of stay. Now, we all can appreciate this – you have a pregnant patient with first trimester vaginal bleeding or abdominal pain, you see an intrauterine pregnancy without any risks/signs of heterotopic (which is incredibly rare anyway) – you’re done! You dont even have to wait for the beta hCG! Of course that decreases length of stay! Now, this wasnt the first study of it’s kind. Another study by Blaivas et al. basically did the same thing… 13 years ago! And by Burgher…. 16 years ago. And by Shih…. 16 years ago! There was a great review of pelvic ultrasound done in 2009 that shows its accuracy and utility too.

Well, here is what they state: abstract below

“OBJECTIVES: Diagnostic ultrasounds by emergency medicine (EM) and pediatric emergency medicine (PEM) physicians have increased because of ultrasonography training during residency and fellowship. The availability of ultrasound in radiology departments is limited or difficult to obtain especially during nighttime hours. Studies have shown that EM physicians can accurately perform goal-directed ultrasound after appropriate training. The goal of this study was to compare the length of stay for patients receiving an ultrasound to confirm intrauterine pregnancies. The hypothesis of this study is that a bedside ultrasound by a trained EM/PEM physician can reduce length of stay in the emergency department (ED) by 1 hour.

METHODS: This was a case cohort retrospective review for patients aged 13 to 21 years who received pelvic ultrasounds in the ED during 2007. Each patient was placed into 1 of 2 groups. Group 1 received bedside ultrasounds done by institutionally credentialed EM/PEM attending physicians. Group 2 received radiology department ultrasound only. Each group had subanalysis done including chief complaint, time of presentation, time to completion of ultrasound, length of stay, diagnosis, and disposition. Daytime was defined as presentation between 7 AM and 9 PM when radiology ultrasound technologists were routinely available.

RESULTS: We studied 330 patients, with 244 patients (74%) in the bedside ultrasound group. The demographics of both groups showed no difference in age, presenting complaints, discharge diagnoses, and ultimate disposition. Group 1 had a significant reduction (P < 0.001) in time to complete the ultrasound compared with group 2 (mean, 82 minutes [range, 1-901 minutes] vs 149 minutes [range, 7-506 minutes]) and length of stay (142 [16-2268] vs 230 [16-844]). Of those presenting during the day (66%), group 1 showed a significant reduction in length of stay (P < 0.001) compared with group 2 (220 [21-951] vs 357 [156-844]). Of those who presented at night (34%), group 1 showed a significant reduction in length of stay (P < 0.002) compared with group 2 (270 [16-2268] vs 326 [127-691]).

CONCLUSIONS: The use of ED bedside ultrasound by trained EM/PEM physicians produced a significant reduction in length of stay in the ED, regardless of radiology ultrasound technologist availability.”

Some interesting cases for your review:

SonoCase: 30 yr old with pelvic pain, LMP 5 weeks ago, stable vitals, mild tenderness in suprapubic area, pelvic exam normal. Your Transabdominal pelvic view on ultrasound shows the below. What do you do next?

Well, we see a full bladder – which is a must if you actually care about your pelvic views – and we see a gestational sac with a double decidua sign – the earliest sign of an intrauterine pregnancy, BUT it is not enough to diagnosis a definitive intrauterine pregnancy – you need a yolk sac within your gestational sac to say that! So, get your endocavitary ultrasound probe and take a look (after emptying the bladder), you may just see the yolk sac!

SonoCase: 24 yr old with pelvic pain, LMP 6 weeks ago, stable vitals, mild tenderness in suprapubic area, pelvic exam normal. Your Transabdominal pelvic view on ultrasound shows below. What is the diagnosis? What do you do next?


Well, there is an empty bladder (unfortunately), so the visualization is not its best, but while we slowly fan through the pelvis there is a fluid filled circular cystic-like structure with mild acoustic enhancement (brightness deep to it) which allows you to also see a gestational sac within the uterus. There is an ovarian cyst. Is that what’s causing the pelvic pain? Are you sure it’s not an ectopic? Not yet – get your endocavitary probe now that the bladder is empty and take a look for the yolk sac or fetal pole. If the fetal pole has cardiac activity visualized then we can say it is a LIVE intrauterine pregnancy.