Ultrasound in the Analysis of the Vomiting Neonate - SD

Introduction

Hi, I am Harris Cohen from the University of Tennessee, as well as Le Bonheur Children's Hospital in Memphis, Tennessee.

I'm going to be discussing ultrasound its use in the analysis of vomiting and neonates and discuss basically three scenarios that are most typical of the vomiting neonate ultrasound in the analysis of the vomiting neonate.

The objective of this discussion is to see imaging options for the analysis of the vomiting neonate and note differential diagnostic considerations, the use of ultrasound in the analysis and techniques for that ultrasound analysis.

Initial Case from 1982

This was a case that was given to me to evaluate in 1982 when I first became interested in ultrasound in the analysis of the gastrointestinal tract, particularly the upper gastrointestinal tract and it's luminal portion, the esophagus, stomach, and duodenum.

An individual ordered an exam on a newborn for abdominal distension hepatomegaly and a dropping hematocrit and assumed there was a possible liver injury status post of forceps delivery.

These were the images, dilated area of bowel was noted with echogenic material within it that was abnormal and atypical in the upper gastrointestinal tract.

The echogenic material seen in a dilated small bowel pointed out by these arrows was followed by another image seen in front of you.

This is an image of the proximal stomach GI tract, which extended in duodenum to a point with an arrow head ending.

And the arrow head ending is particularly indicative of the blind ending loop of small bowel found in patients with mid gut volvulus.

The individuals who had ordered the exam, the clinicians did not believe our diagnosis of mid gut volvulus at the time in an upper GI series was performed.

The upper GI series is seen on the right hand side of the screen and one sees contrast within the esophagus. Air and contrast within the stomach and NG tube is seen going through the stomach to the proximal duodenum.

Contrast is seen in the proximal duodenum with a blind ending in the descending duodenum before it can extend as normal small bowel would've to the left side of the screen and then again up toward the ligament of treitz.

That's the blind ending in the old days.

Early Techniques for Evaluation

In order to evaluate some of these findings, one would have a patient wrapped in a brat board. Sand heavy sandbags would be placed to the side of the patient and we would give the patient barium in order to make a diagnosis in an attempt in the early eighties to see if we could reduce radiation dosages for evaluating some abnormalities of the neonatal upper GI tract for evaluating some abnormalities of the neonatal upper gastrointestinal tract.

We reviewed the use of fluid water as a contrast agent And what did we discover? Water and ultrasound do mix, gastrointestinal ultrasound aided by water as an echo list contrast agent can be used to obtain useful information.

Much of the areas seen within this drawing may be imaged by ultrasound. That includes the distal esophagus, the stomach, the antropyloric region, the descending duodenum, and the duodenum as it crosses transversely over eventually going to the duodenojejunal flexure at the ligament of treitz.

And then extending beyond that is the jejunum, so that distal esophagus, stomach, stomach antrum, pylorus and descending duodenum as well as transverse duodenum can be well seen by ultrasound, particularly if there is echolucent fluid within the lumen.

Fluid aid ultrasound images were similar to those noted on iodinated contrast studies performed by CT at the time.

This is an example of a CT in which contrast is seen in the descending duodenum, just like this is an image of the stomach filled with echolucent material in some debris, probably from milk products that were given to the patient milk because of its contained fat is echogenic and one can see fluid within the descending duodenum.

Images were similar again to those obtained by CT in the transverse duodenum. This is contrast in the transverse duodenum seen between the SMA and the aorta, and a similar image is seen to your right in which fluid is placed into stomach. It has been followed into transverse duodenum and in this image there is fluid within the transverse duodenum and fluid within the stomach.

This is to the left side of midline proving normal rotation and the fact that it is as high as the stomach indicating normal rotation without concern for the subtle mal rotations that are sometimes seen in which bowel crosses over to the left side, but doesn't rise to the level of the duodenum or the duodenal bulb.

The four stands for the fourth portion of the duodenum, and when I see the fourth portion of duodenum filled with fluid directly behind the stomach to the left of midline, I am relatively relieved.

Fluid-Aided Ultrasound of the Luminal Pediatric GI Tract

Fluid aided ultrasound of luminal pediatric GI tract was then studied by us. We did many cases and we came up with several methodologies, most of which I still use today.

We keep the patient NPO prior to the study. We use an eight French 15 or 16 inch nasogastric tube hoping that the tube tip will be near the antrum.

We use hypoallergenic tape to place the tube steady near the nose, and two 60 cc lure slip Syringes are used to empty what stomach contents there are and fill it up with sterile water or Pedialyte or glucose water.

The exam could be performed without placement of an NG tube and by direct bottle feed, but the patient would have to be Very hungry, drink significantly with time in order to get the effect of a bolus placed in the stomach.

So I still prefer when I can to use a nasal gastric tube for filling. The tube is placed into the baby's nose. The baby will cry a few seconds. During the procedure, once it's placed in the stomach and patients who have an NG tube placed into their stomach, one can hear air and one can hear crying to prove its position in the stomach.

Obviously in the old days we used the stethoscope to discover this. Once the fluid is placed in the tube is removed, so there won't be any reflux just because of a tube crossing the GE junction.

And that allows us then to rapidly assess what a stomach filled with fluid and not one waiting for a child to fill looks like.

And one can analyze the stomach then for whether any material goes up in quotes north toward the esophagus or whether it extends without hindrance to the duodenum or whether there is any relative obstruction.

So again, the tube is pulled after fluid placement and listening for the cry when the tube is placed will be an assurance that it's incorrect position For possible VUIs.

One should use minimal fluid and the decision by many experts has been that VUIs is currently favored to be analyzed via the upper GI series. It can still be analyzed via ultrasound, but recommendations by expert panels have suggested that the upper GI series would be easier, particularly for the analysis of volvulus.

Technique for Imaging

So the fluid aided ultrasound of the pediatric GI tract technique. For images, we take images as soon as possible after filling of the stomach, the baby's in supine position.

We look transversely and longitudinally. We look at the antropyloric region. We turn the baby right side down. This helps the fluid extend from stomach to duodenum.

We take transverse and longitudinal images again at the antropyloric region. And if we had trouble finding the region, finding the area of the antropylorus, the antrum, the pylorus, we would look at the gallbladder.

Because the gallbladder and the duodenal bulb are always near each other. We also take longitudinal and transverse views of the esophagus.

The best way of seeing the distal esophagus because that's all we really see. Probably the most distal portion of the esophagus is it enters the stomach and a little portion above the diaphragm.

In order to obtain this image, we do a longitudinal view of the aorta. We point slightly to the left and anterior to the aorta. At the level of diaphragm, one will see the esophagus.

If one cannot find it, one should wait and look again, 'cause it'll be seen. This is a transducer position placed in the midline and slightly to the right of midline Using the original transducer we first did this work on, which was an offset transducer.

There are much better transducers today. We use either a vector four megahertz state megahertz transducer. If we want somewhat better images, we may use a linear array transducer with megahertz of seven or above.

There's some very nice transducers available that weren't available many, many years ago. So again, we try to do a midline longitudinal view, angling slightly to the left to find the distal esophagus.

If we wanna find the pyloric region, we will oftentimes be in a position slightly to the right of midline.

ACR Task Force on Appropriateness Criteria

The ACR task force on appropriateness criteria was created with a desire for input and control over issues of utilization cost and quality of radiologic service.

Patient care guidelines were based on pertinent literature, what was available within the literature as to clinician experience, clinical radiologist experience, and then professional expertise.

The clinical experience of a series of experts, one of the Appropriateness Criteria that were created in pediatrics was vomiting in the first six weeks of life was vomiting in the first six weeks of life.

The rest of this discussion will discuss ultrasound imaging and other imaging for vomiting based upon what was written for that work by the ACR.

Definition of Vomiting and Differential Diagnosis

The first question is what's vomiting? Vomiting is the forceful extrusion of gastric contents. It's never normal in the neonate.

It's usually due to partial or complete obstruction, somewhere between the stomach and ileum.

There may be difficulty in differentiating vomiting from mere regurgitation. Regurgitation is extremely common in children under three months of age.

Vomiting in the first six weeks of life have a differential diagnosis with common causes being gastroesophageal reflux, neonatal sepsis, hypertrophic pyloric stenosis, pyloric spasm, necrotizing enterocolitis in a specific subgroup, the premature infant with bloody stool, there are less common causes.

These include bowel mal rotation with midgut volvulus, which is a clinical emergency mal rotation without volvulus congenital small bowel atresia or stenosis and functional obstructions such as hirschsprung's disease, small left colon syndrome, meconium ileus, or meconium plug syndrome.

Even less common can be the cases of neonatal appendicitis. Intussusception in a less likely group to get into intussusception, IE the first six weeks of life. Gastric outlet obstruction, lactose intolerance and abnormalities beyond the gastrointestinal tract such as intracerebral abnormality, a subdural collection or drug or toxic agents that may cause vomiting or medical conditions such as congenital or medical slash renal abnormality causing vomiting.

When clinical and laboratory findings provided Definitive diagnosis, a treatment plan can be developed without the need for imaging.

It is only when there is medical diagnostic uncertainty that an imaging workup is required. The role of imaging and the evaluation of the vomiting child is to define a point of anatomical obstruction, if any exists.

Secondarily, to note if there is gastroesophageal reflux or delayed gastric emptying.

Three scenarios were looked at for the appropriateness criteria and we will discuss 'em here.

Scenario One: Newborn with Bilious Vomiting

Scenario one, a newborn has bilious vomiting what entity must be considered, although not the most likely, possibly one must consider mid gut volvulus new.

The newborn with bilious vomiting. It's usually due to sepsis or obstruction. This is a radiologic emergency.

Since mid gut volvulus can result in distal bowel ischemia or necrosis, either costing the baby their life on occasion or making them a bowel cripple. If they lose a lot of bowel, it's to be considered an emergency despite the fact that Lillen and Al found 45 patients vomiting in the first 72 hours of life, 32 in the first 24 hours of life who had bilious vomiting.

And among these only 20% had mid gut volvulus. 69% had a transient or idiopathic cause a transient cause and idiopathic cause 11% had a lower GI tract cause such as meconium plug syndrome or small left colon syndrome.

The key imaging question with regard to Bilious vomiting is, is there mechanical obstruction? The upper GI series is a key examination for this analysis for following the flow of contrast from stomach into duodenum across the ligament of treitz using barium preferred by most authors and rarely low osmolarity contrast for the extremely ill or very premature infant.

One can follow the contrast within stomach to small bowel as it extends down the right side, crosses over to the left and then rises to the level of ligament of treitz.

This is an example of an upper GI series in a bilious vomiter and it is abnormal. The small bowel does not cross from right to left. It does not ascend to the level of the bulb. It is not fixed the ligament of treitz.

So one follows the small bowel down here, it actually crosses over to the left pedicle, but continues down in this direction as opposed to normally crossing down, crossing across and then going up to the ligament of treitz.

So this is an image of midgut volvulus Or malrotated bowel that can lead to midgut volvulus that can involve the superior mesenteric artery and if the superior mesenteric artery is compromised, place bowel at risk ultrasound.

Like the upper GI series can image dilated small bowel proximal to an area of atresia stenosis can denote the beaked end of the twist at the end of the obstructed proximal bowel at midgut volvulus, and it can follow fluid because it's echolucent across midline to the area of ligament of treitz.

It obviously can't follow gas within gut because gas is an enemy of ultrasound and will not allow sound to properly go into the area and return to the transducer.

So this is just another example of fluid within proximal duodenum with a blind ending that is arrowhead configuration consistent with another case of midgut volvulus.

And the upper GI series equivalent to this case is very similar in which there is dilated small bowel and never crosses over and then rises, but crosses over and goes straight down as evidence of midgut volvulus.

And here's another image in which debris is seen in the stomach. We didn't add fluid and it can be followed downward and never crossing over to the left side and rising to the area of the expected ligament of treitz.

Some people use the relationship of the superior mesenteric artery. The superior mesenteric vein is a possible clue to bowel mal rotation.

Weinberger in a AJR in 1992 talked about greater than 200 children with non-bilious vomiting. And among those that they studied by ultrasound, they found five of five with the superior mesenteric vein to the left of the SMA opposite of what is typical and one of four with the superior mesenteric vein anterior to the superior mesenteric artery having bowel mal rotation.

And these are images from Weinberger that show the change in position of superior mesenteric artery with superior mesenteric vein that was proven in five of his cases of five cases to be due to malrotation.

This is another Drawing from Kathy's text, which goes over the fact that bowel, when it is embryologically developed into the layout we're used to, goes from a tube to stomach on the left, the descending duodenum on the right and ligament of treitz on the left through a series of actions which include 270 degrees of rotation, 180 degrees of which occur extracoelomically within the umbilical cord and beyond the stomach wall.

And another 90 degrees of rotation occurs after return of the superior GI tract to the abdomen, perhaps at no later than the 12th week or so of embryological life.

So anyway, one should be aware the possibility of mid gut volvulus in patients if small bowel rotates improperly or isn't well attached at the ligament of treitz, or if the normal broad mesenteric band attaching small bowel from ligament of treitz to ileocecal valve is absent, or if Ladd's bands or other points of abnormal fixation are present.

Individuals with unusual layout of their small bowel place their bowel at risk for volvulus and at the same time, place the superior mesenteric artery, which is necessary for the vascular feeding of parts of the bowel at risk.

And this is another image from CFI In this image. One sees the volvulus, one sees the twisting, one sees bowel extending down the right side more than the left side, and this person happens to have their cecum on the left as opposed to the usual right lower quadrant cecum.

Although the position of the cecum should not be what is relied upon, but one should rely on the position of the duodenum and the duodenojejunal junction.

This malposition cecum was noted by the artist have to be part of a malrotated bowel that had four complete turns at the mesenteric root, at the origin of the superior mesenteric artery, and the duodenum was obstructed.

The necessity to be particularly sensitive to bowel rotation was noted by a article of the experience of Children's Hospital of Philadelphia of people who were definitively proven to have mal rotation.

And these images show the various layouts of small bowel in these rotations. So obviously in these cases of mal rotation.

So that one can see that on the first drawing, the small bowel never crosses from right side to left side. That'll be called malrotation by anyone.

The second drawing, 29% of cases, again, doesn't cross from right side to left side, nor does the third image. The fourth image representing only 4% of cases crosses over to the left side, but never rises to the ligament of treitz level.

As is seen with the fifth image as well. The sixth image seems a little tougher to make the diagnosis since there is crossover and it does go superiorly.

So this might be a subset that one would have trouble diagnosing properly, but again, the final image of a group that they knew had mal rotation after surgery shows again non crossover to the left side of the abdomen.

The moral to this is keep very attuned to the layout of your small bowel, which is why some people favor the upper GI series rather than ultrasound.

Although ultrasound can show you this as well and could be followed with fluid in the small bowel.

Scenario Two: Four-Week-Old with Intermittent Non-Bilious Vomiting

The more helpful areas for ultrasound are scenario number two, four week old with intermittent non-bilious vomiting since birth.

The differential diagnosis of chronic vomiting or regurgitation since birth reviewed by O'Keefe in radiology in 1991 showed that in 145 cases, 43 of the cases were due to idiopathic gastroesophageal reflux.

40 cases were due to hypertrophic pyloric stenosis, 27 cases were due merely to overfeeding or voracious eating by the neonate. 15 cases were due to pyloric spasm. 14 cases was due to milk allergy and one case was due to gastroenteritis.

Regurgitation or gastroesophageal reflux is a common finding in the first three months of life. It's usually without an evident etiology and resolves with time.

Some cases are due to displacement of a portion of the stomach into the chest. Other cases implicate theories of lower esophageal sphincter pressures or delayed gastric emptying.

Diagnostic workup of GER in any patient might include the extended pH probe, which is a current standard. The upper GI series, which has greater sensitivity compared to the pH probe, but lower specificity.

So one doesn't know who the really true negatives are. The Tuttle tests and the esophageal motility studies that some people have performed historically are said to be unreliable in a young child.

Ultrasound obviously can be used in the workup. It shows more reflux episodes in the upper GI series for reflux.

Ric Bono in 1992 showed a hundred percent sensitivity and 87.5% specificity. We in 1987 saw 48 true positives, six true negatives and one false negative.

And false negatives can be decreased the longer one looks, it is easier to look via ultrasound where you're not radiating the child than when you radiate the child via upper GI series and don't know when to stop looking.

Some people have used nuclear medicine studies, Which give less radiation than fluoroscopy, but it is not recommended for the first three months of life.

This is an example of ultrasound used to diagnose gastroesophageal reflux. The longitudinal image seen to your left shows air bubbles, which are the bright dots seen in the stomach and also seen in the esophagus seen above the stomach, both below the diaphragm, this echogenic line and above the diaphragm.

This was seen after there was no fluid within the esophagus. The patient was fed via NG tube and everything seen on this image was from stomach extending northward via real time.

This transverse plane image also shows stomach with a few bright dots in it, which is related to aeration and much water is aerated when first placed in.

And the material in the stomach is also seen in the esophagus. The esophagus being posterior to diaphragm here, suggesting that it's within the chest.

So those are two examples of esophageal reflux. This is another example of esophageal reflux arrows point to the very dilated esophagus.

Ultrasound does not show the entire esophagus to evaluate its mucosa, but McCauley Roy McCauley of Boston many years ago said, using upper GI series, the gastroesophageal reflux grading is greatest when the distal esophagus is dilated.

And this methodology can be used with ultrasound and we've used it successfully. With those cases, we're able to perform AVI files, which I'm not including here would certainly help. Audience analysis of the esophageal reflux.

This was a vomiting six day old as possible hypertrophic pyloric stenosis. Fluid was placed in the stomach, fluid was seen in the pyloric channel and in the duodenal bulb going against hypertrophic pyloric stenosis.

But there was a relative hangup, the pyloric channel a little dilated, the duodenal bulb, perhaps a little more apparent over time, and there was a little bit of narrowing beyond it.

We sent the patient to the operating room for probable stenosis duodenum two, the second portion of the duodenum. And we were proven correct.

This is again, a dilated pyloric channel with stenosis in proximal duodenum two, the clinician after we made the diagnosis via ultrasound, required us to prove of the upper GI series.

And this is the upper GI series that showed the narrowing just beyond the dilated duodenal bulb.

This Was another vomiting newborn. There was a question about whether stomach was actually seen within the abdomen. This is not stomach but colon.

And there's a soft tissue mass seen in the left low chest, and that was of concern. We did an ultrasound on the patient and we were able to see stomach with fluid and the aeration within it, anterior to the diaphragm on the right side, but posterior to this echogenic line of diaphragm on the left side, suggesting that part of the stomach was above the diaphragm.

And that was proven via upper GI series in which the, there is a hiatal hernia. The stomach is seen predominantly in the chest and abnormally rotated bowel.

A small bowel is seen extending inferiorly without crossing over or rising superiorly proving it to be malrotated bowel in a patient with a congenital hiatal hernia.

Scenario Three: Six-Week-Old with New Onset Projectile Vomiting

Scenario three is the most common one for ultrasound to be accepted by. Essentially all practitioners six week old with new onset projectile vomiting after having been normal since birth.

New onset projectile vomiting at six weeks has a differential diagnosis including viral gastroenteritis, gastroesophageal reflux, pyloric spasm, and most the thing we're most concerned about is hypertrophic pyloric stenosis.

Hypertrophic pyloric stenosis is idiopathic thickening of circular muscle. It occurs in males to a greater extent than females. It's more common in firstborns. And those with a positive family history, particularly on the maternal side.

Classically, there's a normal infant who develops projectile vomiting at about four to six weeks of age.

Upper GI series is an excellent method for diagnosing obstructive causes of vomiting in this age group. Cases of HPS hypertrophic pyloric stenosis may show on the upper GI series a mass impression on the antrum, the shoulder sign, a filled proximal pylorus, the beak sign, or a filled entire elongated pylorus noted as the string sign.

Each of these have their equivalent the ultrasound, but here are some positive plain film and upper GI series images showing what is known as the caterpillar sign.

One sees an air-filled stomach, which is peristalsing, and hence it looks to some people like a caterpillar walking from the right side of the left side.

This caterpillar sign, this is the beak sign of a little bit of contrast seen in a mass impression on the antrum of the stomach and very little contrast within the pyloric channel.

This is an example of a very elongated pylorus with mass impression on the antrum, the so-called caterpillar sign, the so-called shoulder sign and beak sign, and the so-called string sign.

This is also an upper GI series image of what's known as the double track sign in which contrast within the lumen. Because of pressure from the increased muscle in the pyloric wall, makes the single luminal line look like two or more lines.

Teal and Smith in 1977, first used ultrasound using static contact scanning to denote the mass of hypertrophic pyloric stenosis. This was noted in their New England Journal of Medicine article ultrasound and the diagnosis of idiopathic hypertrophic pyloric stenosis.

This is an example of the bagel or donut sign of HPS in a seven week old first born male projectile vomiting since week four. So the patient hadn't been picked up for a while.

One can see the thickening via all these measurements surrounding the mucosa of the pylorus one sees the thickened wall. All these measurements greater than four millimeters. They measured 5.3 all the way down to 4.1 millimeters.

This is a drawing that shows the equivalent area. This is another image of a thickened elongated pylorus and hypertrophic pyloric stenosis.

Again, there was a thickening of greater than four millimeters, both anterior and posterior, to an elongated pyloric channel whose proximal portion was best seen because there was fluid in the stomach.

You can see how if air was seen in the stomach, one might have had ring down or other problems. The ultrasound image that would not allow one to properly measure the true length of this pyloric channel.

This is an upper GI series in which prior to clinicians accepting ultrasound as a the best tool for hypertrophic pyloric stenosis, I was forced to place a glove on the baby and place contrast into the elongated pylorus via pressure from the stomach in order to prove a case of hypertrophic pyloric stenosis that was readily diagnosed via ultrasound.

This is a more modern linear array transducers showing a case of hypertrophic pyloric stenosis with an elongated pylorus and a very thickened muscle.

Sometimes with the better transducers, you can see these vertical lines within the muscle. This happens to be the gallbladder and you can see the relationship between the gallbladder and the antrum duodenal bulb region.

Criteria for Abnormal Pylorus

So what's an abnormal pylorus, when do you call it positive for hypertrophic Pyloric stenosis Wilson and Van Hoot in 1984 set a two centimeter pyloric length is definitively abnormal in 33 cases.

Stunden in 1986 said all positive cases that they noted were 18 millimeters or longer, and all negative cases were 14 millimeters or less, and we've traditionally used 18 millimeters of length.

And four millimeters of thickness is positive. The four millimeters of thickness is definitively abnormal.

It is well known that you can have positive cases of three millimeters, and I think particularly in the very young or the premature, but if one has an unchangeable greater than three millimeter thickness and an unchangeable 18 millimeter or greater length, we will diagnose the patient is having hypertrophic pyloric stenosis.

I did not have permission to use the monkey, so I won't talk about the monkey. One of the things one has to know in measuring the pylorus is that because the pylorus is somewhat curved, because it goes somewhat posteriorly in the child, because sometimes the child has enough milk products from a previous feed to make it even more difficult to see the pylorus, the measurement of the pylorus is not always best as a straight line, and sometimes one needs a trace method or added straight lines looking at a curve in order to get the true measurements.

So this measurement, which could have been performed as the hypotenuse of a triangle, would've for shortened what is a 2.6 centimeter measurement using a trace method.

Ancillary Ultrasound Findings

Ancillary ultrasound findings hypertrophic pyloric stenosis are just like those of upper GI series. The double track sign can be noted with echogenic parallel lines denoting the mucosal complex of the pylorus, the shoulder sign showing hypertrophic muscle impression on the gastric wall and the mucosal nipple sign or antral heaping sign, which we've called it, which is antral protrusion of redundant pyloric mucosa as the pylorus lengthens.

As there is more significant pressure on the pyloric channel as the mucosa may increase in amount some of it Is almost herniated back into the stomach.

So a small mass of mucosa can be seen proximal to pyloric channel. This is an example of a double track sign in which this child who is given fluid via NG tube, is noted to have two tracks within an elongated pylorus.

The drawing allows you to note how you could get two lines, even though it's one structure, one tube, but impressed upon by hypertrophy of muscle.

This is another example of a double track sign in hypertrophic pyloric stenosis. And this is an example of mucosal heaping in which a little bit of the mucosa is seen within the fluid within the stomach as opposed to the pyloric channel.

Differentiating Pyloric Spasm from Hypertrophic Pyloric Stenosis

So the ultrasound diagnosis from what I've just shown you, you would think would be simple. However, that's a yes and no answer to that.

Pyloric spasm is not tidy group of cases easy to separate from hypertrophic pyloric stenosis. Hernan Schulman, who's written excellent work on hypertrophic pyloric stenosis in a review of HPS noted seven patients with pyloric spasm, their muscle wall thickness range between 1.2 and 2.7 millimeters and their pyloric length between 10 and 14 millimeters, suggesting that there is no problem 'cause there's no crossover with hypertrophic pyloric stenosis.

However, that has not been our experience and we have had crossover of measurement and crossover of image pyloric spasms.

Ultrasound findings can simulate those of hypertrophic pyloric stenosis, although there's a difference in how they're treated. A hypertrophic pyloric stenosis patient goes to surgery and gets a pyloromyotomy, a pyloric spasm patient is watched and usually nothing's done for them.

Some may give them antispasmodics pyloric spasm. Patients can have an elongated length of pylorus. They can have a thickened pyloric muscle. They can have a double track sign.

The main difference is that hypertrophic pyloric stenosis findings are essentially unchangeable during the study. And pyloric spasm patients have changeable findings during the study. Images again may vary during the exam.

This is someone who appears to have any elongated pylorus with thickened pyloric wall muscle looks like hypertrophic pyloric stenosis, but several seconds or minutes later, no longer has any elongated pylorus.

The thickening is only seen in a portion of the area and therefore the patient has pyloric spasm. This is another example, images of pyloric spasm showing what looks like HPS near the gallbladder off the stomach changing a little bit on the next film and on the following cut image one sees a stomach with fluid in it and fluid completely filling antrum and no evidence of muscle or thickened pylorus.

These this is evidence of a double track sign in a patient who proved to have pyloric spasm. That's the antrum. And those are two lines within the pyloric channel, which changed.

And what about the diagnosis with measurements that simple one would think, but it probably isn't. It's yes and no. This is part of a study we performed in which the pyloric length measurement in pyloric stenosis can simulate those of hypertrophic pyloric stenosis.

What we did was we took the longest length of cases of pyloric spasm and marked them on this graph, this chart. And one sees that if one thinks the normal pyloric measurement should be no greater than 18, that at least four of these measurements are above it, and three are at 18.

If one used 14 millimeters, which is not a correct measurement to use, but a measurement reported in at least one textbook, one sees that many of the cases are greater than 14 millimeters in length.

This is another scattergram showing both HPS patients in black and pyloric spasm patients in circles without black in them, noting the wall thickness that they had at the at least the greatest wall thickness during the study.

And you see a large number of HPS and pyloric spasm cases having greater than four millimeters of wall thickness.

We discovered this in 38 cases of hypertrophic pyloric stenosis and 35 cases of pyloric spasm. And again, four millimeters is what's considered definitively positive.

So four millimeters thick does not always mean hypertrophic pyloric stenosis unless it's unchangeable during the study.

So for Pyloric spasm, we watch how the Pylorus handles a fluid load. We check that wall thickness and length measurements Are either abnormal throughout the study or if they're normal. At some point during the study, we bring up pyloric spasm rather than hypertrophic pyloric stenosis, and we see if the pyloric region is changeable.

Changeability suggests pyloric spasm. Patience is a virtue.

Conclusions

So some conclusions. Ultrasound can aid the diagnosis of hypertrophic pyloric stenosis, hypertrophic pyloric stenosis shows little, if any variability of image during an ultrasound study.

This may be of greater importance than actual measurements. Definitively abnormal measurements for HPS are four millimeters of thickness, although we know greater than three millimeters can be positive and an 18 millimeter or greater length for the pyloric channel.

With regard to pyloric spasm, ultrasound aided in its diagnosis in patients with pyloric spasm, variability of the image during the study may be of greater importance than the actual measurements.

Measurements and images may overlap. Those suggesting hypertrophic pyloric stenosis.

The end.