33.Normal and abnormal findings of VF Key points of VF for children

Explanation

This module describes findings obtained by videofluorography (VF) and key points in performing VF in children.

Explanation

Before we start, please check the definitions of the important words used in this module.

Explanation

The first part of this module describes VF findings in adults. To know what normal findings look like, we must fully understand the anatomy of important structures and watch VF movies of normal individuals, such as the movies presented in this module. The abnormal findings presented here are representative examples to give an idea of what the VF findings of aspiration look like. Recently, swallowing evaluation using 1 320-row mulltislice CT scanner has been developed. We will see the 3D-CT images of normal individual acquired from this CT, because these images promote understanding of normal swallow.

Explanation

Here we see the anatomical landmarks that we need to know when evaluating VF findings.

On the right is a static VF image and on the left is a plain X-ray of the same case.

On X-ray images, black areas are where X-rays pass through and white areas are where they do not pass through. So, bones appear white and water and air appear blackish. In this patient, the intensely white areas on the X-ray image represent dental metals or impacted molar teeth (wisdom teeth).

The opposite applies to VF images: white areas are where X-rays pass through and black areas are where they do not pass through. So, barium and bones appear black. This VF image is a static image before swallowing, showing barium in the anterior oral cavity (barium was not used during plain X-ray and is not seen on the X-ray image).

At first glance, the image on the left is clearer because the bone, soft tissue, and air are clearly bordered and the laryngeal cartilage can also be seen. By comparison, the VF image is blurred overall, with the laryngeal cartilage not visible. This is due to the difference in image quality (resolution) between photographs and videos, with the latter having lower resolution. So, structural evaluation should be done using plain X-ray images. It is therefore advisable for X-ray images be taken immediately before VF.

Aspiration is defined as the passage of a food bolus through the glottis. The glottis is composed of the vocal cords, which are thin layers of soft tissue and they are not clearly visualized on X-rays. So, we have to locate the glottis by assuming a line parallel to the cricoid cartilage slightly below the laryngeal prominence in lateral projection (dotted line in the figure. On the X-ray, the laryngeal vestibule is closed; this is not seen on the VF image because the VF image was taken when the larynx was elevated). The laryngeal prominence is therefore an important landmark.

The hyoid bone is another important landmark. The movement of the hyoid bone is known to signal the start of the swallowing reflex. Because the swallowing reflex causes the hyoid to rapidly move upward and forward, the point in time when the hyoid begins to move is recognized as the starting point of the swallowing reflex.

Other important structures in lateral projection include the posterior margin of the hard palate and the intersection of the lower margin of the mandible and the back of the tongue. The posterior margin of the hard palate also represents the border between the oral cavity and pharynx. The intersection of the lower margin of the mandible and the back of the tongue represents the boundary of the oropharynx. The vallecula serves as the upper border of the hypopharynx.

Explanation

These are VF images in anteroposterior (AP) projection. The round object seen at the left of each image is a lead ball, 10 mm in diameter, used as a scale.
Both images cover the area from the oral cavity to the upper esophagus. On the left image taken before swallowing, no important structures can be seen except for the mandible and barium.
On the right image, which is a static image taken immediately before the onset of swallowing, a V-shaped food bolus is being transported and the right and left valleculae and the right and left piriform sinuses  can be seen.
Note that this healthy individual was instructed to intentionally swallow the bolus slowly and such VF findings are usually not obtained.

Explanation

These movies show discrete swallowing of 10 mL of watery barium. The movie on the right is a slow-motion movie showing the swallowing reflex.
Note that the hyoid bone starts to move rapidly immediately before the tip of the bolus reaches the valleculae.
We can also see that while the larynx is elevated, the laryngeal vestibule is completely closed and no air can be seen, indicating complete laryngeal closure.

Explanation

This is a VF image of discrete swallowing of liquid in AP projection. It is difficult to identify the valleculae and piriform sinuses  because this person swallows in a normal way. Almost no laterality in swallowing is seen.

Explanation

The movie on the left shows a person eating 8 g of barium-coated cookie. The bolus moves to the pharynx while being chewed and is swallowed after being accumulated in the oropharynx for a few seconds. This is a typical example of the swallowing pattern in the process model.
The movie on the right shows a person eating a two-phase food mixture consisting of 4 g of semisolid food (barium-containing corned beef) and 5 mL of liquid contrast agent. After chewing starts, the liquid component moves ahead to the pharynx, although swallowing doesn't occur until the liquid reaches the hypopharynx and a substantial amount of the bolus is accumulated in the piriform sinuses. It is very important to note that this swallowing pattern is different from that of the discrete swallow even with the presence of a liquid component.

Explanation

This is a VF movie of chew-swallowing of a cookie (8 g). The object that appears around the right cheek during the movie is a 10-yen coin used as a scale.
You can see that the cookie is placed on the molar teeth on both sides and is processed by the vertical and lateral grinding movements of the jaws.

Explanation

Aspiration is an important finding and can be classified into 3 types depending on whether it occurs before, during, or after swallowing.
This classification helps understand the pathophysiology of aspiration.
Aspiration before the swallow occurs before onset of the swallowing reflex in association with conditions that make the swallowing reflex unlikely to occur, such as severe bulbar palsy, consciousness disturbance, and pseudobulbar palsy. In these conditions, the presence of oral-stage disorders and delayed onset of the swallowing reflex may result in uncontrolled bolus transport to the pharynx without stimulating the reflex.
Aspiration during the swallow occurs when the swallowing reflex occurs with delayed laryngeal closure or incomplete vocal cord closure.
Aspiration after the swallow is caused by the overflow of residual bolus material from the pharynx into the larynx after the swallowing reflex is complete. This type of aspiration is caused by pharyngeal residue, so it is associated with conditions that cause pharyngeal residue such as impaired pharyngeal contraction (reduced intrapharyngeal pressure) and insufficient opening of the UES. It is also possible that food residue in the oral cavity gradually moves to the pharynx and builds up as pharyngeal residue, leading to aspiration (although some investigators insist that this type of aspiration be classified as aspiration before the swallow).

Explanation

This movie shows a VF finding of aspiration before the swallow. The bolus enters the subglottic region before onset of the swallowing reflex.

The bolus falls from the oral cavity into the pharynx in an almost uncontrolled manner without inducing the swallowing reflex. After about 10 s without the swallowing reflex, an attempt is made to induce swallowing by applying physical stimulation with a finger, which results in aspiration (0:09-0:10). A second patient was fed a test food with a syringe. The food bolus was not held in the oral cavity and pooled in the pharynx. When the swallowing reflex occurred, the test food overflowed from the piriform sinuses  into the larynx, causing aspiration (0:14-0:15).

Explanation

This movie shows a VF finding of aspiration during the swallow. The same movie is played twice, with the action paused in the second movie for better visualization of aspiration. Aspiration occurs between onset and completion of the swallowing reflex (at 0:01 and at 0:05-0:06). Although the bolus moved to the pharynx and stimulated the swallowing reflex relatively smoothly, laryngeal penetration and subsequent aspiration occurred due to incomplete vocal cord closure.

Explanation

This movie shows a VF finding of aspiration after the swallow. The patient has cervical spinal deformity causing severe lordosis, with osteophyte formation in the 5th cervical vertebra. Although the swallowing reflex is stimulated smoothly, oropharyngeal pooling occurs during the swallow due to insufficient contraction from oropharynx to hypopharynx s and insufficient laryngeal elevation. This oropharyngeal residue remains in the piriform sinuses  after swallowing. Aspiration occurs before the subsequent swallowing reflex (starting from 0:10).

Explanation

This is a VF movie of aspiration of a two-phase food mixture. Command swallowing of liquid leads to laryngeal penetration, but not to aspiration. However, with a two-phase food mixture, the liquid component enters the subglottic region and causes aspiration (0:14-0:15). Thus, swallowing a two-phase food mixture is a more complicated task than swallowing liquid alone.
Note that the cough reflex did not occur after aspiration in most of the cases presented here. This means that they had silent aspiration. It has been reported that silent aspiration accounts for as many as 70% of all aspiration events detected by VF in patients with suspected dysphagia.

Explanation

In this patient, the upper esophageal sphincter does not open, resulting in bolus material pooling in the valleculae and piriform sinuses . Note that laryngeal penetration is observed halfway through the movie.

Explanation

Head  rotation is one of the maneuvers commonly used in clinical practice. The head is rotated to the opposite side where the bolus is intended to be transported. For example, if we want the bolus to pass through on the right side, rotate the head to the left. In this slide, the food bolus is in the right pharynx, but does not move smoothly into UES due to functional impairment on the right side. When the head is rotated to the right, the bolus moves toward the left, the functional side, and then into the esophagus. (Aspiration of bolus residue from the previous swallow is also observed. This movie is a typical VE finding of aspiration in AP projection.)

Explanation

Here we see a 4D-CT image of normal swallowing captured with a 320-row multislice CT scanner (a movie of a 3D image). This technique is currently in clinical use only in a limited number of institutions for such purposes as kinesiological evaluation of swallowing and detailed analysis of the effect of training.

This movie was created and provided by Dr. Yoko Inamoto from the Faculty of Rehabilitation, School of Heath Sciences, Fujita Health University School of Medicine. This movie is the best example for an overview of the normal swallowing process and should be watched repeatedly for better understanding.

Explanation

The rest of the module now over the key points, especially aspects to be taken care of, when performing VF in children.

Explanation

Children are more worried about undergoing examinations than adults. Just being in a fluoroscopy room, an environment that is very different from their usual environment, can cause them significant psychological stress. So, efforts should be made to minimize this stress. Examiners should establish relationships with the children in advance. It is also advisable for the children's parents and familiar caregivers to be present in the examination room. This makes the children feel more at ease and also helps parents and caregivers to gain a better understanding of the children's problems by observing what happens in the examination. Parents' help may also be needed to have the children capture the test food (eg. when the children refuse the examiner's assistance but accept the parent's).

Be sure that any mother in attendance is not pregnant and is wearing adequate protective gear (that covers all around the waist and neck).

For infants, it is difficult to perform the compensatory swallowing maneuvers used with adults, because they can't understand the instructions. So, it is more important to adjust the child's posture, physical properties of the food, and size of the mouthful. Use an appropriate device to maintain the child in a sitting position in order to reproduce an appropriate posture. Try to use the devices routinely used with the child, if any. Otherwise, use a cushion or pillow that can be placed on the stretcher, with sufficient care to prevent falling.

Children may reject a contrast agent because of its taste and may spit it out. This is more likely to occur when using iodine-based contrast agents due to their bitter taste. Barium also tastes bad, but it is not irritative and children rarely spit it out.

It is difficult to instruct infants to do a command swallow. Therefore, there is no choice but to let them capture and swallow the test food at their own pace. Some children need to capture food at a constant pace and disturbing this pace may lead to aspiration. In some cases, it is necessary to reproduce the regular pace at which they capture food as well as the eating rhythm.

Some children don't experience aspiration during the first half of the meal but do experience it in the last half of the meal. In such cases, consider starting VF before eating, then have the child eat and then perform VF again during the second half of the meal to look for any signs of aspiration.

Explanation

Basically, the same contrast agents as those used in adults can be used in children, such as barium sulfate, although it is advisable to dilute them to lower concentrations than those used in adults to minimize impact in case of aspiration. For children known to be at increased risk of aspiration, the use of iodine-based contrast agents may be considered. These agents are contraindicated in children allergic to iodine. We can determine whether a child has an allergy to a contrast agent by applying a small amount of the agent on the lip and monitoring them for 10 min for allergic signs, such as redness and swelling. Many of the iodine-based contrast agents taste bitter and cannot be used undiluted, but they may lose their contrast-enhancing capacity when diluted too much. When < 0.3 mL is administered, the agent should be used undiluted because it can be substantially diluted by saliva. When ≥ 0.3 mL is administered, the agent can be diluted up to 1:3. Visipaque tastes sweet and is child-friendly even when used undiluted.

Explanation

Here are some ways to help with postural adjustment: a cushion chair mounted on a trolley used in the hospital; a cushion placed on the stretcher; and a child safety seat mounted on an examination chair for VF.

Explanation

The examination procedure is basically the same as that for adults, except that no compensatory swallowing maneuvers can be used. Before starting the examination, make sure that the reclining angle and the size of the mouthfuls are appropriate.

Children who are not eating orally should be placed in a position that minimizes the risk of aspiration, more specifically, a reclined position at around 30°. If this position results in inappropriate neck positioning or abnormal muscle tension, adjust the position by increasing the angle, for example, using a cushion to create a posture that reduces muscle tension. In this new position, start the examination using a very small amount of the test food and observe reactions to determine whether the examination can be continued. When aspiration occurs, change the posture, such as reducing the reclining angle, before continuing with the examination.

Perform the examination in other postures that individual children can easily assume in daily life, considering the possibility for them to eat in this way in daily life. If no major problems are observed with a particular posture, it means that they can eat with that posture. If there is any problem, then it indicates the need for careful postural adjustment.

The initial examination should be performed with a very small amount of test food. In infants, start with as little as 0.1-0.2 mL of test food (using a 1 mL syringe) to examine the series of movements in the oral cavity and pharynx.

For children eating orally, try to reproduce their daily eating conditions during the examination. Try to use spoons and other items of cutlery they actually use in daily life. Although the actual size of mouthfuls in daily life can be used in the examination, a smaller amount should be used in children with suspected aspiration.

Explanation

This movie shows the effect of reclining in an infant whose head is not stabilized.
The movie on the left shows the infant sitting on a cushioned chair and the movie of the right shows the same infant sitting with an additional 30° wedge reclining (see also slide 21).
As seen in this example, in infants whose head is not held up, we can often achieve more stable swallowing by increasing the reclining angle. In children with severe aspiration, aspiration may be prevented by placing them in a horizontal recumbent position.
Horizontal recumbency is not appropriate if it causes overextension of the neck or depression of the tongue base. In such cases, the reclining angle should be adjusted to avoid this.

Explanation

This child doesn't shoe aspiration with the neck in a neutral position but does shoe aspiration with the neck overextended.
Although overextension of the neck generally has a negative impact on swallowing, children whose neck has not been fully stabilized tend to assume this posture. The extent to which the neck can be extended should also be determined. Note that some children need to have their neck extended for ease of breathing and, in these children, the neck cannot be placed in a neutral or anteflexed position.

Explanation

Greater prudence is required when interpreting VF findings in children than in adults.

VF findings from infants may not reflect their actual capabilities, because they are unable to communicate with the examiner and are susceptible to the effects of the environment, as mentioned earlier. Needless to say, in our evaluations, we should consider not only the VF findings, but also the atmosphere of the entire examination situation (eg. whether infants were in a good or bad mood or if they looked different from usual, and how this would affect the findings). When interpreting the obtained findings, we should remember that false-positive or false-negative findings are more likely in infants than in adults.

Whether children can perform direct training and oral feeding should be comprehensively determined from the VF findings, clinical findings, and other examination findings. In the event of aspiration, it is important to determine whether the degree of aspiration is acceptable for the child (i.e. if it could be a false-positive finding), whether it can be improved in a different condition, and whether the condition can be reproduced in actual eating situations in daily life.

Finally, children are growing constantly and this growth is accompanied by morphological and functional changes. If functional growth cannot catch up with morphological growth, swallowing function may deteriorate as they grow. Taking into account such possibilities, we need to plan regular, timely examinations.

References

1. The Japanese Society of Dysphagia Rehabilitation Medical Review Committee. Standard examination method for swallowing contrast (detailed version). Journal of Japanese Society of Dysphagia Rehabilitation 8 (1): 71-86, 2004.
2. J Muray: Videofluoroscopic Examination. in Manual of Dysphagia Assessment in Adults. Singular, San Diego, 1999, pp113-152.
3. Ohmae Y.: The evaluation and diagnosis of dysphagia; Fujishima I (ed.): Yokuwakaru engeshogai 2nd ed. [in Japanese], Nagai Shoten Co., Ltd., Osaka, 2005, pp93-109.
4. Baba M.: The videofluoroscopic examination of swallowing; E Saitoh, Y Mukai (ed.): Dysphagia Rehabilitation 2nd ed. Ishiyaku Publishers, Tokyo, 2007, pp143-152.
5. Y Inamoto, et al.: The effect of bolus viscosity on laryngeal closure in swallowing: kinematic analysis using 320-row area detector CT. Dysphagia 28: 33-42, 2013