High-frequency Intraluminal Ultrasound Research Articles

Comparative study for predictability of type 1 gastric variceal rebleeding after endoscopic variceal ligation: High-frequency intraluminal ultrasound study.

BACKGROUNDThe efficacy of endoscopic ultrasonography for the follow-up of gastric varices treated with endoscopic variceal ligation (EVL) has not been established. AIMTo evaluate the diagnostic correlation of esophagogastroduodenoscopy (EGD) and high-frequency intraluminal ultrasound (HFIUS) for type 1 gastric varices (GOV1) after EVL and to identify the predictability for rebleeding of EGD and HFIUS. METHODSIn liver cirrhosis patients with GOV1, we performed endoscopic follow-up using EGD and HFIUS synchronously after EVL for hemorrhage from GOV1. Endoscopic grading and red color signs were analyzed using EGD, and the largest variceal cross-sectional areas were measured using HFIUS. In addition, 1-year follow-up was performed. Variceal rebleeding was defined as the presence of hematemesis, hematochezia, or melena without other evidence of bleeding on endoscopic follow-up. RESULTSIn 26 patients with GOV1, variceal cross-sectional areas on HFIUS of GOV1 was poorly correlated with EGD grading of GOV1 (r = 0.36). In 17 patients who completed the 1-year follow-up, variceal cross-sectional areas on HFIUS was a good predictor of subsequent rebleeding, whereas EGD grading was not a predictor of subsequent rebleeding. CONCLUSIONHFIUS measurement is more predictive of GOV1 rebleeding than EGD grading, so HFIUS measurement may be necessary for endoscopic follow-up after EVL in patients with GOV1.

Catheter‐based high‐frequency intraluminal ultrasound imaging is a powerful tool to study esophageal dysmotility patients

High-resolution manometry (HRM) is currently the most important diagnostic test for esophageal motility disorders, providing information on the contraction pattern of the circular muscle layer, which helps classify these esophageal motor diseases. However, with the increasing development of ultrasound, other techniques, such as high-frequency intraluminal ultrasound (HFIUS), have gained importance. This technique uses a flexible shaft with a central wire integrated into a standard endoscope, which facilitates real-time sonography. Its main utility is to provide anatomical information on the structure of the esophageal wall, including both the circular and longitudinal layers that constitute the esophageal muscularis propria. Increasing knowledge about these motility disorders has led to the hypothesis that, in addition to an abnormal contraction pattern of the circular muscle, an overall increased muscle thickness and an abnormal longitudinal muscle contraction could be added as pathophysiological factors. The increase in muscle thickness could be an important indicator of the severity of diseases, such as achalasia, distal esophageal spasm, or hypercontractile esophagus. More studies are required before definitive conclusions can be reached, but HFIUS employed simultaneously with HRM could provide a more complete and precise evaluation of these esophageal motor disorders.

Characteristics of esophageal proper muscle in patients with non‐cardiac chest pain using high‐frequency intraluminal ultrasound

It is unclear which mechanisms play a predominant role in the pathogenesis of esophageal non-cardiac chest pain (NCCP). We aimed to examine the features of esophageal proper muscle and esophageal contractility using a high-frequency intraluminal ultrasound (HFIUS) in patients with NCCP. A total of 68 patients with NCCP were classified into two groups according to the results of typical reflux symptoms and/or esophagogastroduodenoscopy and/or 24-h esophageal pH monitoring: gastroesophageal reflux disease (GERD)-positive NCCP (n = 34) and GERD-negative NCCP groups (n = 34). Additionally 16 asymptomatic healthy subjects were included as controls. Using HFIUS, we analyzed the esophageal proper muscle thickness and cross-sectional area (CSA) at 3 cm above lower esophageal sphincter (LES) and 9 cm above LES during baseline rest and peak contraction periods among the control, GERD-positive NCCP and GERD-negative NCCP groups, and examined the completeness of three phases of esophageal action during five wet swallows in the three groups. The muscle thickness and CSA tended to be larger in GERD-negative NCCP than in GERD-positive NCCP and in control groups at esophageal body during both periods. All of the controls and patients with GERD-positive NCCP presented the complete peristaltic type. Whereas, 11 of 34 patients with GERD-negative NCCP presented the incomplete peristaltic type. Using HFIUS, patients with GERD-negative NCCP had increased muscle thickness and CSA. Some GERD-negative NCCP had the incomplete peristaltic type.

A novel pattern of longitudinal muscle contraction with subthreshold pharyngeal stimulus: a possible mechanism of lower esophageal sphincter relaxation.

A subthreshold pharyngeal stimulus induces lower esophageal sphincter (LES) relaxation and inhibits progression of ongoing peristaltic contraction in the esophagus. Recent studies show that longitudinal muscle contraction of the esophagus may play a role in LES relaxation. Our goal was to determine whether a subthreshold pharyngeal stimulus induces contraction of the longitudinal muscle of the esophagus and to determine the nature of this contraction. Studies were conducted in 16 healthy subjects. High resolution manometry (HRM) recorded pressures, and high frequency intraluminal ultrasound (HFIUS) images recorded longitudinal muscle contraction at various locations in the esophagus. Subthreshold pharyngeal stimulation was induced by injection of minute amounts of water in the pharynx. A subthreshold pharyngeal stimulus induced strong contraction and caudal descent of the upper esophageal sphincter (UES) along with relaxation of the LES. HFIUS identified longitudinal muscle contraction of the proximal (3-5 cm below the UES) but not the distal esophagus. Pharyngeal stimulus, following a dry swallow, blocked the progression of dry swallow-induced peristalsis; this was also associated with UES contraction and descent along with the contraction of longitudinal muscle of the proximal esophagus. We identify a unique pattern of longitudinal muscle contraction of the proximal esophagus in response to subthreshold pharyngeal stimulus, which we propose may be responsible for relaxation of the distal esophagus and LES through the stretch sensitive activation of myenteric inhibitory motor neurons.

A 44-Year-Old Female With Dysphagia Presenting a Thin Muscle Thickness on High-Frequency Intraluminal Ultrasound

A 44-year-old female visited the Digestive Disease Center for the evaluation of dysphagia. She complained of severe dysphagia to both solids and liquids for 5 years. Additionally, she regurgitated for 3 years and lost 10 kg for a year. On upper endoscopic finding, the esophageal mucosa appeared to be normal, but there was retained fluid in the distal esophagus and severe contractions leading to resistance in advancing the scope to esophagogastric junction (Fig. 1). Esophagogram showed the dilated aperistaltic esophagus and beaklike narrowing near esophagogastric junction (Fig. 2). High-resolution manometry showed no significant pressurization within the esophageal body with impaired lower esophageal sphincter relaxation (Fig. 3). These findings led to the diagnosis of type 1 achalasia based on a recent high-resolution manometry classification proposed by Pandolfino et al.1 Figure 1 Upper endoscopy. Retained fluid is found in the distal esophagus and powerful contractions are observed on the esophagogastric junction. Figure 2 Esophagogram. This view shows the typical findings of achalasia: dilated aperistaltic esophagus and beaklike narrowing near the esophagogastric junction. Figure 3 High-resolution manometry. There is no significant pressurization within the esophageal body with impaired lower esophageal sphincter relaxation. A number of investigators have reported the use of high-frequency intraluminal ultrasound (HFIUS) to measure muscle thickness and cross sectional area (CSA) of esophagus.2-5 According to the reports using HFIUS, the primary esophageal motility disorders including achalasia, diffuse esophageal spasm and nutcracker esophagus are associated with hypertrophy of the circular as well as longitudinal muscle layers.4 However, HFIUS images in this patient showed a markedly dilated esophagus with a thin muscle thickness (Fig. 4). Additionally, even though the muscle was thin, muscle CSA was larger than the controls from our previous report.5 Figure 4 Muscle thickness and muscle cross sectional area (CSA) in high-frequency intraluminal ultrasound images. The image shows a markedly dilated esophagus with a thin muscle. Note that the muscle CSA is larger (157 mm2), even though the muscle is thin (1.65 ... Interestingly, the presented case showed the thin muscle thickness and large muscle CSA on HFIUS which was different from the traditional type of achalasia presenting a thick muscle thickness.

Oesophageal shortening: in vivo validation of high-frequency ultrasound measurements of oesophageal muscle wall thickness

Background and aimsAssessment of oesophageal muscle wall thickness with high-frequency intraluminal ultrasound (HFIUS) is proposed as a method to evaluate longitudinal muscle contraction and oesophageal shortening in patients with oesophageal...

Change in cross‐sectional area of esophageal muscle does not correlate with the outcome of achalasia after pneumatic balloon dilatation

Patients with achalasia have a thicker muscularis propria compared to normal patients. Because pneumatic balloon dilatation (PD) is an effective treatment for achalasia, the changes in the esophageal muscles after PD may predict treatment outcomes, if muscular change is of primary importance. In the present study, we aimed to observe the changes in esophageal muscle thickness following PD and assessed whether symptom relapse can be predicted on the basis of the esophageal muscle cross-sectional area (CSA), as measured by high-frequency intraluminal ultrasound (HFIUS). Fifteen patients treated by PD were studied and followed up for a median of 3.6 years. An HFIUS was done before PD and 6 months after PD. The esophageal muscle CSA measured at the lower esophageal sphincter (LES), and 3 and 6 cm above the LES, was used to see whether any association was present between symptom recurrence and the esophageal muscle CSA. A single PD resulted in a 2-year remission rate of 66%. A significance variance in change (-65%-248%) was noticed in the muscle CSA after PD. The predilation muscle CSA, post-dilation muscle CSA, and change in the muscle CSA after PD was not associated with symptom recurrence. Our findings suggest that measuring the muscle CSA does not help to predict treatment outcome. Muscular changes in achalasia might be just reactive changes.

418 H. pylori Stimulated Conventional Dendritic Cells Retained Toleragenicity of Immature Dendritic Cells While Upregulating Proinflammatory Cytokines

Background/Aims: Eosinophilic esophagitis (EE) is being recognized with increasing frequency in both pediatric and adult populations. Esophageal manometry, which measure circular muscle (CM) function, shows normal to non-specific motor abnormalities in EE. We observed & describe dysfunctional longitudinal muscle (LM) in EE. METHODS: High frequency intraluminal ultrasound (HFIUS) imaging andmanometry were recorded simultaneously to assess the LM and the CM contraction during swallow-induced peristalsis in 10 normal and 8 patients with EE (histological diagnosis). The US transducer was axially located close to the side hole. 5 ml water swallow were recorded, 2 cm above the LES. RESULTS: Amplitude and duration of CM contraction (measured by manometry) in the controls and patients were not different, (mean amplitude 101 ± 25 vs 90 ± 13 mmHg, and mean duration 3.7 ± 0.7 vs 3.1 ± 0.3 seconds) and pressure waves were peristaltic in both groups. HFIUS images reveal that the baseline muscle thickness was not different between the 2 groups, however there were major differences in the change in muscle thickness during contraction. The peak muscle thickness was significantly smaller in the EE, (peak thickness 3 ± 0.6 ± mm vs 1.69 ± 0.3 mm and duration of muscle thickness increase 4.6 ± 1.1 vs 1.6 ± 0.2 seconds, (P<0.001). In controls, the muscle thickness from baseline to peak was 121% (range 65% to 214%) , in the EE patients it was increased 37% (range 20% to 49%). In normal subjects the CM and LM contract simultaneously but in patients contractions were asynchronous (delta time 0.03 secs in normal and 0.7 seconds in patients (P<0.01)). In 1 patient there was complete dissociation between the CM and LM contraction (EE 1 in Fig 1). CONCLUSIONS: In patients with EE the LM function is significantly impaired even though the CM function is preserved. The role of LM dysfunction in the pathogenesis of dysphagia in EE requires further investigation.

Asynchrony Between the Circular and the Longitudinal Muscle Contraction in Patients With Nutcracker Esophagus

The increases in intraluminal pressure and muscle cross-sectional area (CSA) during esophageal contraction are markers of circular and longitudinal muscle contractions. The goal of our study was to determine temporal synchrony between circular and longitudinal muscle contraction in healthy subjects and patients with nutcracker esophagus. Pressure and high-frequency intraluminal ultrasound (HFIUS) images were recorded simultaneously in healthy subjects and patients with nutcracker esophagus at 2 and 10 cm above the lower esophageal sphincter during wet swallow. HFIUS images were digitized and analyzed for the muscle CSA. The time interval (delta-t) between the peak muscle CSA and the peak pressure was determined. In healthy subjects, a close temporal correlation existed between the peak contraction pressure and the peak muscle CSA with a maximum delta-t of 0.5 seconds at the 2- and 10-cm levels (0-0.5 seconds). On the other hand, the patient group had a median delta-t of 1.25 seconds (0.75-3.5 seconds) at the 2-cm level and 0.75 seconds (0-2.0 seconds) at the 10-cm level. Ninety-eight of 103 contractions in patients showed a delta-t >0.5 seconds. There was a significant correlation between delta-t and the amplitude of pressure wave, the duration of pressure wave, and the peak muscle CSA. The duration of pressure wave but not the duration of CSA wave was longer in patients with nutcracker esophagus as compared with healthy subjects. Patients with nutcracker esophagus show temporal asynchrony between the contractions of circular and longitudinal muscle layers.

Motor and Sensory Function of the Esophagus

Catheter based high frequency intraluminal ultrasound (HFIUS) imaging is a powerful tool to study esophageal sensory and motor function and dysfunction in vivo in humans. It has provided a number of important insights into the longitudinal muscle function of the esophagus. Based on the ultrasound images and intraluminal pressure recordings, it is clear that there is synchrony in the timing as well as the amplitude of contraction between the circular and the longitudinal muscle layers of the esophagus in normal subjects. On the other hand, in patients with spastic disorders of the esophagus, there is an asynchrony of contraction related to the timing and amplitude of contraction of the two muscle layers during peristalsis. Achalasia, diffuse esophageal spasm, and nutcracker esophagus (spastic motor disorders of the esophagus) are associated with hypertrophy of the circular as well as longitudinal muscle layers. A sustained contraction of the longitudinal muscle of the esophagus is temporally related to chest pain and heartburn and may very well be the cause of symptoms. Longitudinal muscle function of the esophagus can be studied in vivo in humans using dynamic ultrasound imaging. Longitudinal muscle dysfunction appears to be important in the motor and sensory disorders of the esophagus.

Measuring esophageal distention by high-frequency intraluminal ultrasound probe

This investigation used a high-frequency intraluminal ultrasound (HFIUS) probe to study changes in esophageal muscle thickness as a marker of muscle contraction. The aim of this study was to determine whether this technique could accurately measure distention of the esophagus during swallows of liquid bolus and during gastroesophageal reflux (GER) in normal subjects. Despite some limitations, HFIUS appears to be a valid technique for both of these measurements in normal subjects. Future studies in patients with symptomatic GER disease (GERD) should be able to determine whether typical symptoms such as heartburn, as well as atypical symptoms such as chest pain, are related to the GER-related distention of the esophagus.

Distension-related responses in circular and longitudinal muscle of the human esophagus: an ultrasonographic study.

Both circular muscles (CM) and longitudinal muscles (LM) of the esophagus participate in peristalsis. Various measurement techniques have yielded conflicting information as to the temporal correlation between contraction in the two muscle layers. High-frequency intraluminal ultrasound (HFIUS) is a novel technique to detect contraction of LM and CM of the esophagus. We investigated the temporal correlation between the CM and LM contraction during ascending excitatory and descending inhibitory reflexes using HFIUS. A manometric catheter equipped with two balloons and a 12.5-MHz ultrasound transducer catheter was used to study 10 normal healthy subjects. The changes in muscle thickness and pressure, proximal and distal to esophageal distension, were recorded at 5 and 10 cm above the lower esophageal sphincter (LES). The esophageal distension induced an increase in pressure and an increase in muscle thickness of both CM and LM layers proximal to the distension site. The onset of increase in muscle thickness and peak muscle thickness in two layers occurred at the same time. There was a close temporal correlation between the changes in pressure and changes in muscle thickness. Atropine inhibited the distension-related pressure and muscle thickness increase in both layers. Distal to the esophageal distension, there was no change in pressure but a decrease in the thickness of the two muscle layers. The decrease in muscle thickness of the two layers occurred at the same time. The responses of the two muscle layers to distension were similar at 5- and 10-cm sites above the LES. HFIUS is a relatively noninvasive technique to study the LM layer response during peristalsis in vivo. Our data indicate that the two muscle layers may contract and relax together during distension-related peristaltic reflexes in the esophagus.