Morphologic parameters of normal swallowing events using single-shot fast spin echo dynamic MRI

Is it possible to reveal a typical swallowing pattern for specific skeletal malocclusion types using M-mode sonographic imaging of tongue movements?

PURPOSE

The present study aims to compare the M‑mode ultrasound findings of different skeletal malocclusions and to evaluate whether sonographic parameters can be used for the diagnosis of malocclusions.

METHODS

Tongue movements of 36 adolescents aged between 10.37 and 17.29 years (mean 14.25 ± 1.78 years) were assessed using simultaneous two-dimensional real-time B‑mode and M‑mode sonography. The swallowing patterns of the subjects were visualized recording the motion of the tongue surface in the ultrasound images utilizing a fixed scan line through the middle of the tongue. M‑mode scans of tongue motion during empty deglutition were recorded. The parameters range, duration, and speed were computed for the entirety of the swallowing process using M‑mode examination. Findings were evaluated and statistically analyzed.

RESULTS

No clear intraindividual repeatability in the M‑mode imaging of the subjects' swallowing process could be observed. Considering the setup used in the study, it was not always possible to distinguish individual swallowing stages in the M‑mode images with regard to the chosen reference points. The average duration, range of motion, and speed of swallowing were found to be 2.43 s, 24.06 mm, and 10.34 mm/s, respectively. The findings showed both intra- and intersubject variability during empty swallowing.

CONCLUSION

With the help of the metrics that could be calculated based on the M‑mode images, it was not possible to differentiate the swallowing acts of different skeletal malocclusion types. It remains unclear whether M‑mode imaging can accurately visualize the swallowing pattern. Therefore, further progress in technology and multidisciplinary work is needed in order to establish diagnostic references regarding swallowing.

Kinematics of lateral tongue-pushing movement in coordination with masticatory jaw movement: An anteroposterior projection videofluorographic study

OBJECTIVE

During the mastication of solid food, the tongue pushes the bolus laterally to place it onto occlusal surfaces as the jaw is opened. This movement is referred to as tongue-pushing (TP). TP has an important role in efficient chewing, but its kinematic mechanisms remain unclear. The present study quantified the kinematics of TP and its coordination with masticatory jaw movements.

METHODS

Videofluorography (VFG) in anteroposterior projection was recorded while 14 healthy young adults ate 6 g each of cookies and meat. Small lead markers were glued to the tongue surface (left, right, and anterior) and buccal tooth surfaces (upper molars and lower canines). The position of the tongue and lower canine markers relative to the upper occlusal plane was quantified with Cartesian coordinates, using the right upper molar as the origin. Jaw motion during chewing was divided into TP and Non-TP cycles, based on the lateral movement of the food and tongue markers. The side of the jaw that compressed food particles was defined as the working side, while the other side was termed the balancing side. Horizontal and vertical displacements of tongue and jaw markers were compared between TP and Non-TP cycles, as well as between food types.

RESULTS

The mediolateral displacement of all tongue markers was significantly larger in TP than in Non-TP cycles. Vertical displacement was also significantly greater in TP than in Non-TP cycles for the anterior and working side tongue markers. TP cycles occurred more frequently with meat-chewing than with cookie-chewing.

CONCLUSION

TP is accomplished by rotation and lateral movements of the tongue surface on the working side and the anterior tongue blade, along with medial movement on the balancing side. These movements produce lateral shift and rotation of the tongue surface toward the working side in concert with jaw opening. Designing exercises to improve the strength of the lateral motion and rotation of the tongue body may be useful for individuals with impaired tongue function for eating and swallowing.

Adaptability of the tongue during orthodontic apparatus treatment

To date, most dentoalveolar deformities are associated with bad habits such as thumb sucking, tongue sticking out, and so on. According to the authors, protrusion of the tongue is normal in newborns, in which the tongue lies between the gingival pads, and the lower jaw is stabilized by the facial muscles during swallowing. With the eruption of temporary teeth, this physiological phenomenon disappears. The authors pointed out that there are such concepts as «simple tongue push» and «complex tongue push». The first relates to open bite push-outs. The second is observed in children with an open bite, as well as with respiratory complications and / or with a history of chronic diseases of the nasopharynx. The act of swallowing in the physiological sense is divided into 3 stages: oral, pharyngeal and esophageal. Each stage is characterized by different positions of the tongue in the oral cavity. Orthodontic hardware treatment of such patients is aimed at eliminating these habits, as well as correcting the bite. Although many studies have been conducted since 1965, to this day, aimed at studying the tongue protrusion in infantile swallowing, as well as in various malocclusion deformities, the authors found that these studies have shortcomings. For each patient, the shape, size, as well as the trajectory of movements may vary due to anatomical features (short frenulum of the tongue). In this review article, the authors consider such concepts as the adaptive ability of the tongue during infantile swallowing, as well as its trajectory of movements when using various methods of hardware treatment; various orthodontic devices for the treatment of tongue misalignments, their components and their purposes are described. The current classification, main characteristics of this pathological condition and its connection with the dentoalveolar system are considered. Based on the study, it can be concluded that there are several directions in the treatment of infantile swallowing. One of these areas is hardware treatment in the form of the use of plates with a flap for the tongue.

3D-CT Evaluation of Swallowing: Metrics of the Swallowing Response Using Swallowing CT

Videofluoroscopy and videoendoscopy dramatically changed the evaluation and management of swallowing disorders. Later advancements in techniques for the instrumental evaluation of swallowing were limited by technique and positioning. The advent of 320-row area detector CT solved previous challenges and allowed for the study of swallowing physiology and dysphagia in greater detail. In this summary, we describe the history and evolution of CT technology and describe research and clinical applications for the evaluation of swallowing physiology and pathophysiology.

Evaluation of velopharyngeal function using high-speed cine-magnetic resonance imaging based on T2-weighted sequences: a preliminary study

The objective was to introduce a new technique for visualizing the three-dimensional (3D) movements of velopharyngeal-related muscles using high-speed cine-magnetic resonance imaging (MRI) based on T2-weighted sequences. The evaluation of phonation- and water swallowing-related events was performed in 11 healthy subjects. Specifically, whether cine-MRI could precisely visualize normal velopharyngeal function during these two events was examined. The 3D movements of the soft palate, superior pharyngeal constrictor muscles, and levator veli palatini muscles were visualized in all 11 subjects. A noteworthy finding was that the magnetic resonance signals of the superior constrictor pharyngeal muscles and the levator veli palatini muscles were significantly higher during phonation and during water swallowing than at rest. This initial study suggests that the 3D movements of velopharyngeal-related muscles can be successfully and precisely visualized without side effects. The magnetic resonance signal changes seen in the superior pharyngeal constrictor and levator veli palatini muscles using the technique described here should be useful to develop better methods of evaluation of velopharyngeal function.

The physiological linkage between molar inclination and dental macrowear pattern

OBJECTIVES

Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between antagonist teeth by testing the hypothesis that tooth inclination is one of the mechanisms driving distribution of wear in masticatory phases in addition to dietary and cultural habits.

MATERIALS AND METHODS

The present work investigates the relationship between dental macrowear patterns and tooth inclinations on a sample of complete maxillary and mandibular 3D models of dental arches from 19 young and adult Yuendumu Aboriginal individuals. The analysis was carried out on first molars (M1) from all quadrants. Occlusal Fingerprint Analysis was used for the quantification of macrowear patterns, and 2D cross-sectional geometric analysis was carried out to investigate asymmetry in dental arches.

RESULTS

The asymmetry is highly variable on both arches, and it is associated with differences in the inclination of upper M1 crowns. Each molar has variable inclination (buccal/lingual) which influence tooth to tooth contact, producing greater or lesser variation in wear pattern. Interindividual variability of morphological variation of the occlusal relationship has to be considered in macrowear analysis.

DISCUSSION

Our results suggest that overall asymmetry in the masticatory apparatus in modern humans affects occlusal contact areas between antagonist teeth influencing macrowear and chewing efficiency during ontogeny.

Tongue Shape Dynamics in Swallowing Using Sagittal Ultrasound

Ultrasound imaging is simple, repeatable, gives real-time feedback, and its dynamic soft tissue imaging may make it superior to other modalities for swallowing research. We tested this hypothesis and measured certain spatial and dynamic aspects of the swallowing to investigate its efficacy. Eleven healthy adults wearing a headset to stabilize the probe participated in the study. Both thickened and thin liquids were used, and liquid bolus volumes of 10 and 25 ml were administered to the subjects by using a cup. The tongue's surface was traced as a spline superimposed on a fan-shaped measurement space for every image from the time at which the tongue blade started moving up toward the palate at the start of swallowing to the time when the entire tongue was in contact with the palate. To measure depression depth, the distance (in mm) was measured along each radial fan line from the location at which the tongue's surface spline intersected the fan line to the point where the hard palate intersected the fan line at each timepoint. There were differences between individual participants in the imageability of the swallow, and so we defined quantitatively "measureable" and "unmeasurable" types. The most common type was measureable, in which we could find a clear bolus depression in the cupped tongue's surface. Indeed, with 10 ml of thin liquids, we were able to find and measure the depression depth for all participants. The average maximum radial distance from the palate to the tongue's surface was 20.9 mm (median) (IQR: 4.3 mm) for swallowing 10 ml of thin liquid compared to 24.6 mm (IQR: 3.3 mm) for 25 ml of thin liquid swallow (p < 0.001). We conclude that it is possible to use ultrasound imaging of the tongue to capture spatial aspects of swallowing.

Application of B+M-Mode Ultrasonography in Assessing Deglutitive Tongue Movements in Healthy Adults

Background

The purpose of this study was to evaluate tongue movements during swallowing in healthy adults using the B+M-mode ultrasonography, and to determine a common feature in the M-mode traces for quantitative measurement and individual comparison of tongue movements.

Material/Methods

Ninety healthy subjects were divided into 3 groups according to age (20–39, 40–59, and 60–80 years). The tongue movements during 3 saliva swallows were examined using real-time B+M-mode ultrasonography. The M-mode traces of tongue movements were recorded and evaluated.

Results

Both intra-individual and inter-individual differences were detected in the M-mode traces during the 3 saliva swallows. Characteristic types were seen during the individual swallowing phases of M-mode traces: 2 activity types in phase I, 2 types in phase IIb, and 3 types in phase III. However, no variations were seen during phase IIa, in which all subjects displayed a continuous upsloping trace. The average range of swallow-related tongue radial displacement during phase IIa decreased gradually with age, while the average duration of tongue movement during phase IIa increased gradually with age. These 2 trends were not statistically significant across age groups. However, differences between sexes were found in both the range of tongue radial displacement and the duration of deglutitive lingual actions during phase IIa in all 3 age groups (P<0.05).

Conclusions

B+M-mode ultrasonography may offer a quick and safe alternative for the preliminary evaluation of deglutitive tongue movements.

Sequential coordination between lingual and pharyngeal pressures produced during dry swallowing

The aim of this study was to investigate oropharyngeal pressure flow dynamics during dry swallowing in ten healthy subjects. Tongue pressure (TP) was measured using a sensor sheet system with five measuring points on the hard palate, and pharyngeal pressure (PP) was measured using a manometric catheter with four measuring points. The order and correlations of sequential events, such as onset, peak, and offset times of pressure production, at each pressure measuring point were analyzed on the synchronized waveforms. Onset of TP was earlier than that of PP. The peak of TP did not show significant differences with the onset of PP, and it was earlier than that of PP. There was no significant difference between the offset of TP and PP. The onset of PP was temporally time-locked to the peak of TP, and there was an especially strong correlation between the onset of PP and TP at the posterior-median part on the hard palate. The offset of PP was temporally time-locked to that of TP. These results could be interpreted as providing an explanation for the generation of oropharyngeal pressure flow to ensure efficient bolus transport and safe swallowing.

The use of high-speed, continuous, T2-weighted magnetic resonance sequences and saline for the evaluation of swallowing

OBJECTIVE

To introduce a new high-speed, continuous, T2-weighted magnetic resonance imaging (MRI) technique for the evaluation of swallowing by visualizing the flow of saline.

STUDY DESIGN

In 20 healthy participants, high-speed (10 frames per second), continuous MRI of the pharynx and larynx was performed during administration of 5 mL of saline. The extent to which fluid flow and swallowing (including flow to the esophagus or trachea) could be visualized was determined for all 20 participants.

RESULTS

Solution flow was visualized, and swallowing events, including the direction of flow to the esophagus, could be visualized with high-speed, continuous MRI for all 20 participants.

CONCLUSIONS

This initial study suggests that the visualization of saline flow using our method may facilitate functional evaluation of swallowing without side effects.

Optimization of parameter settings in cine-MR imaging for diagnosis of swallowing

Videofluorography is frequently used to evaluate swallowing and is considered the "gold standard" among imaging modalities. This modality, however, has several disadvantages, including radiation exposure and limitations in the detection of soft tissues. Conversely, magnetic resonance imaging (MRI) offers excellent contrast resolution in soft tissue without radiation exposure. A major drawback of MRI in evaluating swallowing, however, is that temporal resolution is poor. The aim of this study was to investigate a new cine-MRI modality. Imaging parameters were optimized and the efficacy of this new technique is discussed. Three techniques for speeding up MRI were combined: true fast imaging with steady state precession, generalized auto-calibrating partially parallel acquisition, and key-hole imaging. The effects of the receiver coils used, receiving bandwidth, slice thickness, and flip angle on each image were determined. The optimal imaging parameters obtained comprised a reduction factor of 2, receiving bandwidth of 1,000 Hz/pixel (repetition time of 151.7 milliseconds and echo time of 1.4 milliseconds), flip angle of 50°, and slice thickness of 6 mm. Neck and spine coils were used. Under these conditions, the new cine-MR imaging technique investigated showed a temporal resolution of 0.1 sec/slice (10 frames/sec). Even with optimized parameter settings, this technique did not allow a true temporal resolution of 30 frames/sec by a large margin. Motion artifacts persisted. Further study is needed on how to speed up this technique.

Analysis of passive motion of para- and retropharyngeal structures during swallowing using dynamic magnetic resonance imaging

The purpose of this study was to analyze passive motion of the para- and retropharyngeal space (PRS) during swallowing using dynamic magnetic resonance imaging (MRI). We conducted a preliminary study involving 30 healthy volunteers who underwent dynamic MRI. Consecutive MRI axial images were obtained by examining the plane parallel to the hard palate at the level of the anterior inferior corner of C2. Anterior displacement of the posterior pharyngeal wall (PPW) was measured as a motion index of pharyngeal contraction. The displacement and internal angle of the bilateral external and internal carotid arteries (ECA and ICA) and the bilateral centroids of the PRS area, as well as the increase in PRS area, were calculated at rest and at maximum pharyngeal contraction. In most participants, the bilateral ECA, ICA, and centroids were anterointernally displaced by pharyngeal contraction. The normalized ECA displacement (r = 0.64, r (2) = 0.41), normalized ICA displacement (r = 0.60, r (2) = 0.37), and normalized centroid displacement (r = 0.43, r (2) = 0.19) were more than moderately positively correlated with the normalized PPW displacement. The normalized PRS area increase (r = 0.35, r (2) = 0.12) was weakly positively correlated with the normalized PPW displacement. These results revealed that PRS area increased as the ECA and ICA were drawn anterointernally via its passive motion by pharyngeal contraction.

Evaluation of swallow function after tongue cancer treatment using real-time magnetic resonance imaging: a pilot study

IMPORTANCE

Magnetic resonance imaging (MRI) has the advantage of imaging swallow function at any anatomical level without changing the position of patient, which can provide detailed information than modified barium swallow, by far the gold standard of swallow evaluation.

OBJECTIVE

To investigate the use of real-time MRI in the evaluation of swallow function of patients with tongue cancer.

DESIGN, SETTING, AND PARTICIPANTS

Real-time MRI experiments were performed on a Signa Excite HD 1.5-T scanner (GE Healthcare), with gradients capable of 40-mT/m (milli-Tesla per meter) amplitudes and 150-mT/m/ms (mT/m per millisecond) slew rates. The sequence used was spiral fast gradient echo sequence. Four men with base of tongue or oral tongue squamous cell carcinoma and 3 age-matched healthy men with normal swallowing participated in the experiment.

INTERVENTIONS

Real-time MRI of the midsagittal plane was collected during swallowing. Coronal planes between the oral tongue and base of tongue and through the middle of the larynx were collected from 1 of the patients.

MAIN OUTCOMES AND MEASURES

Oral transit time, pharyngeal transit time, submental muscle length change, and the distance change between the hyoid bone and anterior boundary of the thyroid cartilage were measured frame by frame during swallowing.

RESULTS

All the measurable oral transit and pharyngeal transit times of the patients with cancer were significantly longer than the ones of the healthy participants. The changes in submental muscle length and the distance between the hyoid bone and thyroid cartilage happened in concert for all 60 normal swallows; however, the pattern differed for each patient with cancer. To our knowledge, the coronal view of the tongue and larynx revealed information that has not been previously reported.

CONCLUSIONS AND RELEVANCE

This study has demonstrated the potential of real-time MRI to reveal critical information beyond the capacity of traditional videofluoroscopy. Further investigation is needed to fully consider the technique, procedure, and standard scope of applying MRI to evaluate swallow function of patients with cancer in research and clinic practice.

Dynamic magnetic resonance imaging of the pharynx during deglutition

OBJECTIVES

We utilized dynamic magnetic resonance imaging to visualize the pharynx and upper esophageal segment in normal, healthy subjects.

METHODS

A 3-T scanner with a 4-channel head coil and a dual-channel neck coil was used to obtain high-speed magnetic resonance images of subjects who were swallowing liquids and pudding. Ninety sequential images were acquired with a temporal resolution of 113 ms. Imaging was performed in axial planes at the levels of the oropharynx and the pharyngoesophageal segment. The images were then analyzed for variables related to alterations in the area of the pharynx and pharyngoesophageal segment during swallowing, as well as temporal measures related to these structures.

RESULTS

All subjects tolerated the study protocol without complaint. Changes in the area of the pharyngeal wall lumen and temporal measurements were consistent within and between subjects. The inter-rater and intra-rater reliabilities for the measurement tool were excellent.

CONCLUSIONS

Dynamic magnetic resonance imaging of the swallow sequence is both feasible and reliable and may eventually complement currently used diagnostic methods, as it adds substantive information.

Relationship between Class III malocclusion and hyoid bone displacement during swallowing: a cine-magnetic resonance imaging study

Objective

The displacement of the hyoid bone (HB) is a critical biomechanical component of the swallowing function. The aim of this study was to evaluate the swallowing-induced vertical and horizontal displacements of the HB in subjects with 2 different magnitudes of skeletal Class III malocclusion, by means of real-time, balanced turbo-field-echo (B-TFE) cine-magnetic resonance imaging.

Methods

The study population comprised 19 patients with mild skeletal Class III malocclusion, 16 with severe skeletal Class III malocclusion, and 20 with a skeletal Class I relationship. Before the commencement of the study, all subjects underwent cephalometric analysis to identify the nature of skeletal malformations. B-TFE images were obtained for the 4 consecutive stages of deglutition as each patient swallowed 10 mL of water, and the vertical and horizontal displacements of the HB were measured at each stage.

Results

At all stages of swallowing, the vertical position of the HB in the severe Class III malocclusion group was significantly lower than those in the mild Class III and Class I malocclusion groups. Similarly, the horizontal displacement of the HB was found to be significantly associated with the severity of malocclusion, i.e., the degree of Class III malocclusion, while the amount of anterior displacement of the HB decreased with an increase in the severity of the Class III deformity.

Conclusions

Our findings indicate the existence of a relationship between the magnitude of Class III malocclusion and HB displacement during swallowing.

Assessment of swallowing and its disorders-a dynamic MRI study

Magnetic resonance imaging overcomes the limitations of videofluoroscopy in assessing without radiation exposure. The clinical utility of dynamic MRI for swallowing disorders is not well documented. This study demonstrates the feasibility of using dynamic MRI in assessment of swallowing disorders. Ten normal and three brainstem lesion patients participated in this study. GE Signa HDxt 1.5 Tesla MRI scanner with head-and-neck coil as a receiver and fast imaging employing steady state acquisition sequence was used. The swallow was analyzed in terms of symmetry and amplitude of movements of velum, faucial pillars, tongue, epiglottis and cricopharyngeous and images from the sagittal, coronal and axial planes. In sagittal plane posterior movement of tongue and its compression on velum, elevation of hyoid bone, elevation of larynx and lid action of epiglottis, in the coronal view the symmetrical movements of the faucial pillars and pharyngeal constrictor muscles and in axial plane three anatomical landmarks were targeted based on their role in swallowing, viz. velum, epiglottis and cricopharyngeous were studied. In brainstem lesion individuals, posterior movement of tongue, and elevation of larynx were not seen. Asymmetrical movements of faucial pillars and cricopharyngeous muscle were appreciated in the dynamic MRI. This demonstrates that, dynamic MRI is an efficient tool to understand the swallowing physiology and helps the speech language pathologist in modifying the swallowing maneuvers. Dynamic MRI is an effective tool in assessing swallowing and its disorders. This muscle specific information is not appreciated in videofluoroscopy and this information is necessary to modify the therapy maneuvers.

3 Tesla turbo-FLASH magnetic resonance imaging of deglutition

OBJECTIVES/HYPOTHESIS

In this article we describe a methodology for obtaining high-quality dynamic magnetic resonance imaging (MRI) sequences of the swallow sequence in healthy volunteers. The study includes comparison to previous work done in our lab using a 1.5 Tesla (T) magnet.

STUDY DESIGN

Case series.

METHODS

Three healthy volunteers underwent turbo-fast low angle shot MRI at 3T while swallowing liquid boluses delivered via intravenous tubing to the oral cavity. Imaging was performed in the sagittal and axial planes.

RESULTS

Imaging provided by this sequence provided high temporal resolution, with the ability to depict deglutition in the axial and sagittal planes. Comparison with imaging at 1.5 T demonstrated benefits in temporal resolution and signal-to-noise. Anatomic information provided differed from comparative videofluoroscopy.

CONCLUSIONS

MRI of swallowing using the described technique is reliable and provides a unique evaluation of the swallowing sequence.

Cine MRI of swallowing in patients with advanced oral or oropharyngeal carcinoma: a feasibility study

Treatment of oral and oropharyngeal cancer may cause dysphagia. Purpose is to examine whether cine magnetic resonance imaging (MRI) yields additional information compared to standard examination in the evaluation of posttreatment dysphagia and mobility of oral and oropharyngeal structures. Thirty-four cine MRIs were made in 23 patients with advanced oral and oropharyngeal cancer, consisting of an MR image every 800 ms during swallowing which is compared to videofluoroscopy and quality of life questionnaires. A scoring system was applied to assess mobility on cine MR and videofluoroscopy leading to a score ranging from 9 to 17. Cine MRI of the swallowing in a midsagittal plane visualized the tumor (if located in the same plane), important anatomic structures and surgical reconstructions. Posttreatment mobility on cine MRI and videofluoroscopy was significantly diminished compared to pretreatment, mean pretreatment cine MRI score was 10.8 and posttreatment 12.4 (p = 0.017). Impaired mobility on cine MRI was significantly correlated to more swallowing problems (Spearman's correlation coefficient 0.73, p = 0.04), on videofluoroscopy not. Cine MRI is a promising new technique as an adjunct to standard examinations for evaluation of swallowing in patients with oral and oropharyngeal cancer. Cine MRI directly visualizes the dynamics of swallowing and allows evaluation of pre- and posttreatment differences. Abnormal findings are significantly correlated with subjective swallowing complaints of patients.

Effect of complete denture wearing on deglutition time: a cine-magnetic resonance imaging study

Purpose of the study was to evaluate the effect of complete denture wearing on deglutition time (DT), hyoid bone and larynx movements in edentulous patients with real-time balanced turbo field echo cine-magnetic resonance imaging. Subjects were examined by cine-magnetic resonance imaging in supine position during swallowing water. Two sets of images for 23 edentulous (with/without wearing complete dentures) and one for 23 dentulous patients were obtained. Radiographic outputs representing three consecutive deglutition stages (oral, pharyngeal and oesophageal) were provided to perform measurements. Deglutition time significantly increased when edentulous patients wore their dentures (mean 0·75 s increased to 1·17 s), whereas dentulous patients' DT was about 0·91 s (P ≤ 0.05). The duration of deglutition is crucial because prolonged pharyngeal transit times increases the risk of aspiration. Within the limitations of the study, complete denture wearing could increase the shortened DT of the edentulous patients.

Functional magnetic resonance in the evaluation of oesophageal motility disorders

Functional magnetic resonance imaging (fMRI) has been recently proposed for the evaluation of the esophagus. Our aim is to assess the role of fMRI as a technique to assess morphological and functional parameters of the esophagus in patients with esophageal motor disorders and in healthy controls. Subsequently, we assessed the diagnostic efficiency of fMRI in comparison to videofluoroscopic and manometric findings in the investigation of patients with esophageal motor disorders. Considering that fMRI was shown to offer valuable information on bolus transit and on the caliber of the esophagus, variations of these two parameters in the different types of esophageal motor alterations have been assessed. fMRI, compared to manometry and videofluoroscopy, showed that a deranged or absent peristalsis is significantly associated with slower transit time and with increased esophageal diameter. Although further studies are needed, fMRI represents a promising noninvasive technique for the integrated functional and morphological evaluation of esophageal motility disorders.

Tongue movements in patients with skeletal Class III malocclusions evaluated with real-time balanced turbo field echo cine magnetic resonance imaging

INTRODUCTION

The aim of this study was to evaluate the position and movements of the tongue in patients with skeletal Class III malocclusion.

METHODS

Sixty-six patients (31 male, 35 female) with Class III malocclusion were divided into 3 groups according to cephalometric analysis. The first group comprised 23 patients (13 male, 10 female) with mandibular prognathism, the second group comprised 21 patients (9 male, 12 female) with maxillary retrognathism, and the third group comprised 22 patients (9 male, 13 female) with both maxillary retrognathism and mandibular prognathism. Twenty-two skeletal Class I patients (10 male, 12 female) were also included as the control group.

RESULTS

Dentofacial morphology affects the position and the movements of the tongue during deglutition. Contact of the anterior portion of the tongue with the rugae area of the hard palate decreased in the Class III malocclusion groups. The posterior portion of the dorsal tongue was positioned more inferiorly, and the root of the tongue was positioned more inferiorly and anteriorly in patients with Class III malocclusion than in the control group. The tip of the tongue was also in a more anterior position in the Class III groups. When the deglutition stages were evaluated, we observed that the manner of bolus transfer was different in patients with skeletal Class III malocclusion than in those with skeletal Class I malocclusion.

CONCLUSIONS

Tongue posture is affected by dentofacial structures, and adaptive changes occur in the tip, dorsum, and root of the tongue. Deglutitive tongue movements in patients with skeletal Class III malocclusion are also different from those with skeletal Class I malocclusion.

Novel 16-channel receive coil array for accelerated upper airway MRI at 3 Tesla

Upper airway MRI can provide a noninvasive assessment of speech and swallowing disorders and sleep apnea. Recent work has demonstrated the value of high-resolution three-dimensional imaging and dynamic two-dimensional imaging and the importance of further improvements in spatio-temporal resolution. The purpose of the study was to describe a novel 16-channel 3 Tesla receive coil that is highly sensitive to the human upper airway and investigate the performance of accelerated upper airway MRI with the coil. In three-dimensional imaging of the upper airway during static posture, 6-fold acceleration is demonstrated using parallel imaging, potentially leading to capturing a whole three-dimensional vocal tract with 1.25 mm isotropic resolution within 9 sec of sustained sound production. Midsagittal spiral parallel imaging of vocal tract dynamics during natural speech production is demonstrated with 2 × 2 mm(2) in-plane spatial and 84 ms temporal resolution.

B-mode and M-mode Ultrasonography of Tongue Movements during Swallowing

OBJECTIVE

This study investigated the possibility of using B-mode and M-mode ultrasonography to differentiate between the visceral and somatic swallowing patterns.

SUBJECTS AND METHODS

Tongue movements during empty swallowing by 11 volunteers with a visceral swallowing pattern were traced in B-mode and M-mode ultrasound imaging before and after successful myofunctional therapy. Thirteen subjects with a somatic swallowing pattern served as the control group. We examined and compared the B-mode sequences and M-mode images of at least six of each study subject's swallowing processes for reproducible characteristics and parameters.

RESULTS

We observed wide intraindividual variability, making interindividual comparison difficult or meaningless. We identified no qualitative characteristic features in B-mode imaging that could be designated as solely visceral or physiological swallowing movements. There was no obvious intraindividual reproducibility in the M-mode sonogram of the swallowing act. Given the experimental set-up we used (without a submandibular cushioning pad), it was not possible to differentiate individual swallowing phases, that is, the initial, transporting, and returning phases, on the M-mode images based on characteristic trace points, as described in the literature. We determined the amplitude and velocity of vertical tongue movement as well as total swallowing duration on the M-mode images. These parameters revealed wide intra- and interindividual variability.

CONCLUSIONS

No qualitative differences could be established in B-mode imaging with the ultrasound method selected for this study. The parameters that could be measured on the M-mode images are not suitable for differentiating between visceral and somatic swallowing.

Cine-MRI swallowing evaluation after tongue reconstruction

OBJECTIVE

To determine the feasibility of cine-MRI for non-invasive swallowing evaluation after surgery for lingual carcinoma with reconstruction using microvascular free flaps.

METHODS

Ten patients with stage IV carcinoma of the mobile tongue and/or tongue base treated by surgical resection and reconstruction with a free flap were evaluated after an average of 4.3 years (range: 1.5-11 years), using cine-MRI in "single-shot fast spin echo" (SSFSE) mode. Fiberoptic laryngoscopy of swallowing was performed before MRI to detect aspiration. The tolerance and ability to complete the exam were noted. The mobilities of the oral and pharyngeal structures visualized were evaluated as normal, reduced or increased.

RESULTS

Cine-MRI was well tolerated in all cases; "dry" swallow was performed for the 2 patients with clinical aspiration. Tongue base-pharyngeal wall contact was observed in 5 cases. An increased anterior tongue recoil, increased mandibular recoil, increased posterior oropharyngeal wall advancement and an increased laryngeal elevation were observed in 4 cases. One case of a passive "slide" mechanism was observed.

CONCLUSIONS

Cine-MRI is a safe, non-invasive technique for the evaluation of the mobility of oral and oropharyngeal structures after free-flap reconstruction of the tongue. For selected cases, it may be complementary to clinical examination for evaluation of dysphagia after surgery and free-flap reconstruction. Further technical advances will be necessary before cine-MRI can replace videofluoroscopy, however.

Dynamic imaging of swallowing in a seated position using open-configuration MRI

PURPOSE

To assess the feasibility of dynamic MRI of swallowing in a seated position using an open-configuration MRI scanner, and to compare its capacity for motion analysis around the pharyngeal wall with that of videofluorography.

MATERIALS AND METHODS

Six healthy individuals (four women and two men, mean age = 31.4 +/- 7.5 years) were examined with an open-configuration MRI system using a fast spoiled gradient-recalled echo (SPGR) sequence. Dynamic imaging was performed while the subjects were in a seated position after they swallowed oral contrast medium from a cup. An oral and maxillofacial radiologist measured the motion of six structures: the hyoid bone (HB), larynx (LX), upper oropharynx (UOP), lower oropharynx (LOP), pharyngoesophageal segment (PES) behind the vocal folds, and upper esophagus (ESO). The measured motions were compared with reported values from videofluorography-based observations.

RESULTS

Open-configuration MRI depicted the anatomic structures related to swallowing (lip, tongue, soft palate, mandible, pharynx, HB, LX, and PES), and the course of the mylohyoid muscle (MM). The vertical and anteroposterior displacements of these structures did not differ significantly from those measured by videofluorography.

CONCLUSION

Dynamic imaging of swallowing using open-configuration MRI provides image information comparable to that obtained from videofluorography.

Cine magnetic resonance imaging with single-shot fast spin echo for evaluation of dysphagia and aspiration

The aim of this study was to determine the feasibility of and interest in evaluation of swallowing using dynamic magnetic resonance imaging (cine-MRI) in patients with dysphagia and aspiration caused by an abnormal pharyngeal phase of swallow. A cohort of six patients previously treated for head and neck cancer with persistent dysphagia and/or aspiration were evaluated an average of 47 months after treatment. The morphology and mobility of the oral, oropharyngeal, and laryngeal structures were analyzed using cine-MRI using single-shot fast spin echo technology. The qualitative observations were compared with a clinical fiberoptic swallowing evaluation. Swallowing physiology was analyzable for dry (saliva) swallow in all patients. MRI was well-tolerated by all six patients and no clinical aspiration occurred during the MRI. In five of six cases, further information on the cause of dysphagia was obtained using cine-MRI compared with the clinical evaluation alone. In the remaining case, cine-MRI confirmed the clinical evaluation. Cine-MRI using the dry swallow technique is feasible and without risk in patients with clinical aspiration. Cine-MRI is complementary to clinical evaluation of swallowing in patients with an abnormal pharyngeal phase of swallowing resulting from treatment of cancer.

Dynamic MR imaging of the gastroesophageal junction in healthy volunteers during bolus passage

PURPOSE

To evaluate the feasibility of noninvasive dynamic fast magnetic resonance imaging (MRI) during swallowing in healthy volunteers, and to determine esophageal function at the gastroesophageal junction during swallowing.

MATERIALS AND METHODS

A total of 20 healthy volunteers underwent MRI while swallowing in the supine position. Dynamic gradient-echo (GRE) sequences (balanced fast field echo [B-FFE]) were employed in three planes on a 1.5T unit using a phased-array body coil. Buttermilk spiked with gadolinium (Gd) chelate (40:1) for bolus passage was used as an oral contrast agent. We evaluated visualization of esophageal bolus transit, bolus transit time (BTT), peristalsis, identification of the gastroesophageal junction, and reflux during the Valsalva maneuver.

RESULTS

The mean visible length of the esophagus was 16.2+/-5.3 cm in the sagittal view, and 13.8+/-4.9 cm in the coronal view. In the sagittal view the BTT was defined in 15 of 20 volunteers and was 7.6+/-1.4 seconds. The BTT in the coronal view was measured in seven of 20 volunteers and was 8+/-1.3 seconds on average. The axial view yielded higher scores (2.25) than the coronal (1.98) and sagittal (1.78) views for identification of the cardia and during the Valsalva maneuver. Bolus contrast was better displayed in the sagittal (2.2) view than in the coronal (2.08) or axial (1.73) planes. In six volunteers, gastroesophageal abnormalities, such as axial hernia, reflux, and nonperistaltic contractions, were identified. For statistical analysis we used the Friedman test and a one-way analysis of variance (ANOVA).

CONCLUSION

The results indicate that dynamic MR swallowing is a feasible and reproducible technique that warrants further studies in patients.

Dynamic MRI Evaluation of Tongue Posture and Deglutitive Movements in a Surgically Corrected Open Bite

Tongue thrust usually develops in the presence of anterior open bite in order to achieve anterior valve function. In the literature, tongue thrust is described both as the result and the cause of open bite. If it is an adaptation to malocclusion, then tongue posture and deglutitive tongue movements should change after treatment. In this case report, an adult who had skeletal open bite and Class II malocclusion caused by mandibular retrusion was treated surgically. The mandible was advanced in a forward and upward direction with a sagittal split osteotomy. The open bite and Class II malocclusion were corrected and an increase in the posterior airway space (PAS) was observed. Pretreatment and posttreatment dynamic magnetic resonance imaging (MRI) revealed that tongue tip was retruded behind the incisors and contact of the tongue with the palate increased. It was also determined that the anterior and middle portions descended, whereas the posterior portion was elevated at all stages. Advancement of the mandible, correction of open bite, and an increase in PAS affected not only the tongue posture and deglutitive movements, but also the breathing pattern of the patient.

Real time balanced turbo field echo Cine-MRI in the analysis of deglutition events and transit times

Investigation of swallowing is an important part of oral diagnosis. It usually plays a role in the aetiology of some orofacial deformities and open-bite as well as in the relapse of treated open-bite patients. In recent years, the movements of the anatomical structures that participate in deglutition have been investigated by several methods such as cineradiography, electromyography, electropalatography, electromagnetic articulography and ultrasonography. However, all these techniques have various disadvantages. Recently, dynamic magnetic resonance imaging has become available in the evaluation of swallowing function. In this study we intended to present this new technique to the dental literature and aimed to obtain dynamic images of the deglutition process. We also compared the timing of events in subjects with anterior open-bite and normal overbite during swallowing 10 mL water.

Real-time balanced turbo field echo cine-magnetic resonance imaging evaluation of tongue movements during deglutition in subjects with anterior open bite

INTRODUCTION

The aim of this study was to evaluate tongue movements in subjects with anterior dental open bites during deglutition by using real-time balanced turbo field echo cine-magnetic resonance imaging.

METHODS

The study included 28 subjects. Two groups were formed according to the presence of anterior open bite (at least 2 mm). The open-bite group (OBG) consisted of 18 patients (14 girls, 4 boys) with a mean age of 14.5 +/- 2.7 years. The control group (CG) consisted of 10 patients (5 girls, 5 boys) with a mean age of 14.5 +/- 2.6 years. We evaluated deglutition during 3 stages: oral (stage 1), pharyngeal (stage 2), and esophageal stage (3).

RESULTS

Results indicated that (1) in the OBG, from stage 2 to stage 3, the anterior portion of the tongue dorsum was elevated [corrected] whereas its midportion was lowered [corrected]; (2) in the CG, its posterior portion was lowered [corrected] from stage 2 to stage 3; (3) in the CG, the tongue tip was positioned more posteriorly [corrected] at stage 2 than at stage 1; (4) in the OBG, the tongue tip moved more anteriorly in all stages of deglutition than in the CG.

CONCLUSIONS

Compensatory tongue functions occur in patients with anterior dental open bites. Dynamic MRI is a promising tool for evaluating swallowing patterns in these patients.