Velopharyngeal Incompetence in Children With 22q11.2 Deletion Syndrome: Velar and Pharyngeal Dimensions.

ABSTRACT: The surgical management of velopharyngeal incompetence (VPI) in children with 22q11.2 deletion syndrome (22q11.2 DS) is challenging. There are numerous approaches and children often undergo more than one operation. Our aim was to develop a method using images from routine lateral videofluoroscopy to study the dimensions of the velopharynx in this cohort.We analyzed 22 pre-operative lateral videofluoroscopy recordings of children with 22q11.2 DS and VPI. Fourteen had a submucous cleft palate (SMCP) and 8 had no obvious palatal abnormality but who were subsequently labelled as having an occult submucous cleft palate (OSMCP). The control data were 10 historic records of children with cleft lip and an intact palate. The authors identified key points on radiographs of the velum at rest and when elevated to measure the total velar length, functional velar length and pharyngeal depth and compared them ratiometrically.The intra-observer reliability was > 0.9 whereas the inter-observer reliability was > 0.74. The velopharyngeal depth/total velar length was significantly greater in 22q11.2 DS than the control group P < 0.001. There was no difference between SMCP and OSMCP patients, P = 0.556. There was no difference in the functional velar length/total velar length between 22q11.2 DS and controls (P = 0.763).In this study, the authors demonstrate a reliable method to gain useful ratiometric measurements of the velopharynx. This may help with treatment planning. Children with 22q11.2 DS and VPI have a larger velopharyngeal depth/total velar length ratio that may explain some of the difficulty in management.

Comparison of Cartesian and Non-Cartesian Real-Time MRI Sequences at 1.5T to Assess Velar Motion and Velopharyngeal Closure during Speech.

Dynamic imaging of the vocal tract using real-time MRI has been an active and growing area of research, having demonstrated great potential to become routinely performed in the clinical evaluation of speech and swallowing disorders. Although many technical advances have been made in regards to acquisition and reconstruction methodologies, there is still no consensus in best practice protocols. This study aims to compare Cartesian and non-Cartesian real-time MRI sequences, regarding image quality and temporal resolution trade-off, for dynamic speech imaging. Five subjects were imaged at 1.5T, while performing normal phonation, in order to assess velar motion and velopharyngeal closure. Data was acquired using both Cartesian and non-Cartesian (spiral and radial) real-time sequences at five different spatial-temporal resolution sets, between 10 fps (1.7×1.7×10 mm3) and 25 fps (1.5×1.5×10 mm3). Only standard scanning resources provided by the MRI scanner manufacturer were used to ensure easy applicability to clinical evaluation and reproducibility. Data sets were evaluated by comparing measurements of the velar structure, dynamic contrast-to-noise ratio and image quality visual scoring. Results showed that for all proposed sequences, FLASH spiral acquisitions provided higher contrast-to-noise ratio, up to a 170.34% increase at 20 fps, than equivalent bSSFP Cartesian acquisitions for the same spatial-temporal resolution. At higher frame rates (22 and 25 fps), spiral protocols were optimal and provided higher CNR and visual scoring than equivalent radial protocols. Comparison of dynamic imaging at 10 and 22 fps for radial and spiral acquisitions revealed no significant difference in CNR performance, thus indicating that temporal resolution can be doubled without compromising spatial resolution (1.9×1.9 mm2) or CNR. In summary, this study suggests that the use of FLASH spiral protocols should be preferred over bSSFP Cartesian for the dynamic imaging of velopharyngeal closure, as it allows for an improvement in CNR and overall image quality without compromising spatial-temporal resolution.

Impact of orthodontic appliances on the quality of craniofacial anatomical magnetic resonance imaging and real-time speech imaging.

AIMS: The aim of this work was to investigate the effects of commonly used orthodontic appliances on the magnetic resonance (MR) image quality of the craniofacial region, with special interest in the soft palate and velopharyngeal wall using real-time speech imaging sequences and anatomical imaging of the temporomandibular joints (TMJ) and pituitaries. METHODS: Common orthodontic appliances were studied on 1.5 T scanner using standard spin and gradient echo sequences (based on the American Society for Testing and Materials standard test method) and sequences previously applied for high-resolution anatomical and dynamic real-time imaging during speech. Images were evaluated for the presence and size of artefacts. RESULTS: Metallic orthodontic appliances had different effects on image quality. The most extensive individual effects were associated with the presence of stainless steel archwire, particularly if combined with stainless steel brackets and stainless steel molar bands. With those appliances, diagnostic quality of magnetic resonance imaging speech and palate images will be most likely severely degraded, or speech imaging and imaging of pituitaries and TMJ will be not possible. All non-metallic, non-metallic with Ni/Cr reinforcement or Ni/Ti alloys appliances were of little concern. LIMITATIONS: The results in the study are only valid at 1.5 T and for the sequences and devices used and cannot necessarily be extrapolated to all sequences and devices. Furthermore, both geometry and size of some appliances are subject dependent, and consequently, the effects on the image quality can vary between subjects. Therefore, the results presented in this article should be treated as a guide when assessing the risks of image quality degradation rather than an absolute evaluation of possible artefacts. CONCLUSIONS: Appliances manufactured from stainless steel cause extensive artefacts, which may render image non-diagnostic. The presence and type of orthodontic appliances should be always included in the patient's screening, so the risks of artefacts can be assessed prior to imaging. Although the risks to patients with fixed orthodontic appliances at 1.5 T MR scanners are low, their secure attachment should be confirmed prior to the examination.

Speech MRI: morphology and function.

Magnetic Resonance Imaging (MRI) plays an increasing role in the study of speech. This article reviews the MRI literature of anatomical imaging, imaging for acoustic modelling and dynamic imaging. It describes existing imaging techniques attempting to meet the challenges of imaging the upper airway during speech and examines the remaining hurdles and future research directions.

Model validation for a noninvasive arterial stenosis detection problem.

A current thrust in medical research is the development of a non-invasive method for detection, localization, and characterization of an arterial stenosis (a blockage or partial blockage in an artery). A method has been proposed to detect shear waves in the chest cavity which have been generated by disturbances in the blood flow resulting from a stenosis. In order to develop this methodology further, we use one-dimensional shear wave experimental data from novel acoustic phantoms to validate a corresponding viscoelastic mathematical model. We estimate model parameters which give a good fit (in a sense to be precisely defined) to the experimental data, and use asymptotic error theory to provide confidence intervals for parameter estimates. Finally, since a robust error model is necessary for accurate parameter estimates and confidence analysis, we include a comparison of absolute and relative models for measurement error.

High-order space-time finite element schemes for acoustic and viscodynamic wave equations with temporal decoupling.

We revisit a method originally introduced by Werder et al. (in Comput. Methods Appl. Mech. Engrg., 190:6685-6708, 2001) for temporally discontinuous Galerkin FEMs applied to a parabolic partial differential equation. In that approach, block systems arise because of the coupling of the spatial systems through inner products of the temporal basis functions. If the spatial finite element space is of dimension D and polynomials of degree r are used in time, the block system has dimension (r + 1)D and is usually regarded as being too large when r > 1. Werder et al. found that the space-time coupling matrices are diagonalizable over [Formula: see text] for r ⩽100, and this means that the time-coupled computations within a time step can actually be decoupled. By using either continuous Galerkin or spectral element methods in space, we apply this DG-in-time methodology, for the first time, to second-order wave equations including elastodynamics with and without Kelvin-Voigt and Maxwell-Zener viscoelasticity. An example set of numerical results is given to demonstrate the favourable effect on error and computational work of the moderately high-order (up to degree 7) temporal and spatio-temporal approximations, and we also touch on an application of this method to an ambitious problem related to the diagnosis of coronary artery disease. Copyright © 2014 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons Ltd.

Adaptive averaging applied to dynamic imaging of the soft palate.

Achieving sufficient temporal and spatial resolution with adequate signal-to-noise ratio (SNR) in dynamic soft palate imaging is challenging. Triggered acquisitions require repeated reproducible speech samples, and while real-time imaging is more reliable, it may lack SNR. Adaptive averaging was implemented to improve SNR in nongated imaging during repetition of a speech task. Similar images were identified using localized cross-correlation before averaging. Adaptive averaging was applied to the soft palate region of images from six volunteers and one patient acquired with various sequences. In volunteers, soft palate SNR increased by 53 ± 17% with four averages. The additional SNR was used to enable reduced slice thickness in two example subjects. Adaptive averaging was also compared to pseudotriggered images in one example and, in another, it was applied to an unrepeated speech task. In a patient with a repaired cleft palate, the technique was used to demonstrate residual velopharyngeal insufficiency. This initial work demonstrates that increased temporal or spatial resolution may be traded for reduced SNR, which can be recovered using adaptive averaging. This will be a valuable tool in assessing velopharyngeal function, particularly in pediatric patients where cooperation may make gated studies difficult or when their head sizes require increased spatial resolution while maintaining temporal resolution.

Assessment of tissue Doppler imaging measurements of arterial wall motion using a tissue mimicking test rig.

The aim of this in vitro study is to assess the accuracy of the tissue Doppler imaging arterial wall motion (TDI AWM) technique in measuring dilation over a range of distances and velocities. A test rig, consisting of two parallel blocks of tissue mimicking material (TMM), has been developed to generate known wall motion. One block remains stationary while the other moves in a cyclical motion. A calibrated laser range finder was used to measure the TMM motion. The TDI AWM measurements were found to underestimate the dilation by 21% +/- 4.7% when using the recommended scanner parameters. The size of the error was found to increase with a decrease in ultrasound output power. Results suggested that errors in the TDI AWM dilation measurements relate to underestimates in the velocity measured by the TDI technique. The error demonstrated in this study indicates a limitation in the value of TDI AWM result obtained in vivo. (E-mail: abigail.thrush@bartsandthelondon.nhs.uk).

A new SWL titanium stent (Zebra Stent): resistance to shockwave exposure.

BACKGROUND AND PURPOSE: Recently, a new-concept lumen-less Teflon-coated double-J wire stent (Zebra stent) has been introduced to facilitate residual stone clearance, in particular after SWL. Its metal core expresses highly mismatched acoustic impedance. It was the aim of this study to exclude damage to the stent through shockwaves. Also, its Teflon coating should to some degree prevent encrustation, and stents removed from stone formers were examined for encrustation. MATERIALS AND METHODS: Series of 2000 shockwaves of an average and a maximum energy were applied to defined areas of Zebra stents in a waterbath on a Siemens Multiline Lithotriptor. Stents were then examined for core and sheath damage by digital photography, scanning electron microscopy, and microradiography. In addition, two Zebra stents and one conventional double-J stent from two stone formers were assessed in the same way for damage and encrustation. RESULTS: There was no damage whatsoever to either of the stents. Whereas there was considerable encrustation on the conventional double-J stent, there was none on the Zebra stents after 4 and 5 weeks in situ. CONCLUSIONS: Zebra stents resist shockwaves to a maximum number and energy sufficiently to be applied safely under SWL. Whether they resist encrustation to a higher degree in the short term than conventional stents remains to be established.

Surgical management of velopharyngeal incompetence in velocardiofacial syndrome.

OBJECTIVES: To analyze the results of surgery for velopharyngeal incompetence (VPI) in velocardiofacial syndrome. DESIGN: Prospective data collection, with randomized, blind assessment of speech and velopharyngeal function on lateral videofluoroscopy and nasendoscopy. SETTING: Two-site, tertiary referral cleft unit. PATIENTS: Forty-two consecutive patients with the 22q11 deletion underwent surgery for symptomatic VPI by a single surgeon. INTERVENTIONS: Intraoral examinations, lateral videofluoroscopy (+/- nasendoscopy) and intraoperative evaluation of the position of the velar muscles through the operating microscope. Based on these findings, either a radical dissection and retropositioning of the velar muscles (submucous cleft palate [SMCP repair]) or a Hynes pharyngoplasty (posterior pharyngeal wall augmentation pharyngoplasty) was performed. As anticipated, a proportion of patients undergoing SMCP repair subsequently required a Hynes. The aim of this staged approach was to maximize velar function, thereby enabling a less obstructive pharyngoplasty to be performed. Thus, there were three surgical groups for analysis: SMCP alone, Hynes alone, and SMCP+Hynes. MAIN OUTCOME MEASURES: Blind perceptual rating of resonance and nasal airflow; blind assessment of velopharyngeal function on lateral videofluoroscopy and nasendoscopy; and identification of predictive factors. RESULTS: Significant improvement in hypernasality in all three groups. The SMCP+Hynes group also showed significant improvement in nasal emission. There were significant improvements in the extended and resting velar lengths following SMCP repair and a trend toward increased velocity of closure. CONCLUSIONS: Depending on velopharyngeal anatomy and function, there is a role for SMCP repair, Hynes pharyngoplasty, and a staged combination of SMCP+Hynes, all of which are procedures with a low morbidity.

Submucous cleft palate: a grading system and review of 40 consecutive submucous cleft palate repairs.

OBJECTIVES: This study was designed to determine whether velar surgery was worthwhile for submucous cleft palate (SMCP) and evaluate whether results were dependent on the degree of the anatomical abnormality. DESIGN: A prospective study of a consecutive series of patients fulfilling the entry criteria, assessed blindly from records arranged randomly. PATIENTS: Fifty-eight patients diagnosed with SMCP and operated on by a single surgeon between June 1991 and April 1997 were reviewed. Forty patients fulfilled the entry criteria. Minimum follow-up was 6 years. INTERVENTION: Radical reconstruction of the soft palate musculature was performed by one surgeon using the operating microscope. A scoring system was devised for grading the anatomical severity of submucous cleft (SMCP score). MAIN OUTCOME MEASURES: Postoperative hypernasality and nasal emission scores and the degrees of improvement were considered the primary outcome measures, and the degree of velopharyngeal closure was also assessed. RESULTS: There were highly significant improvements in hypernasality, nasal emission, and velopharyngeal closure. A preoperative gap size of more than 13 mm was associated with less satisfactory outcomes, but gap size was not predictive of improvement. Severity of the SMCP did not correlate with the degree of preoperative speech abnormality but was a significant predictor of outcome of surgery, with the less severe (total SMCP score of 0 to 3) having less satisfactory end results and lesser degrees of improvement. Patients with less abnormal muscle anatomy had lesser degrees of improvement. CONCLUSION: Repair of the muscle abnormality in SMCP is recommended as the first line of treatment in most cases.

Rectal heat thresholds: a novel test of the sensory afferent pathway.

PURPOSE: Currently, rectal sensation may be measured by balloon distention or mucosal electrostimulation. This study investigated the application of a graded heat stimulus to the rectum using a novel thermal probe as a further method of evaluating rectal sensory afferent mechanisms. METHODS: A thermal probe specially designed in our institution was used to test rectal heat sensitivity in 31 healthy subjects. This was compared with all other standard anorectal physiologic measurements. Repeatability studies were also performed. RESULTS: Heat stimulation of the mid rectum elicited sensory responses in all subjects. The most common reported response was not heat but a sharp or prickling sensation. The median rectal heat threshold was similar in males (median, 47 degrees C; range, 44-50 degrees C) compared with females (median, 45 degrees C; range, 43-50 degrees C; P > 0.05). There was a high degree of repeatability with rectal heat and balloon distention thresholds, but not electrostimulation thresholds. A strong correlation was found between rectal heat thresholds and defecatory desire (r = 0.71; P < 0.001) and maximum tolerable volumes (r = 0.8; P < 0.001) measured with balloon distention. CONCLUSION: This is the first demonstration of a repeatable sensory response to heat stimulation in the rectum of normal subjects. Strong correlation between heat thresholds and balloon distention to maximum tolerable volumes and defecatory desire suggest common sensory afferent pathway excitation. Heat stimulation is a simple technique that has a high degree of repeatability and may be an objective assessment of polymodal nociceptor function in the rectum.

Palate re-repair revisited.

OBJECTIVE: To analyze the results of a consecutive series of palate re-repairs performed using the operating microscope and identify predictive factors for outcome. DESIGN: Prospective data collection, with blind assessment of randomized recordings of speech and velar function on lateral videofluoroscopy and nasendoscopy. PATIENTS: One hundred twenty-nine consecutive patients with previously repaired cleft palates and symptomatic velopharyngeal incompetence (VPI) and evidence of anterior insertion of the levator veli palatini underwent palate re-repairs by a single surgeon from 1992 to 1998. Syndromic patients, those who had significant additional surgical procedures at the time of re-repair (23 patients), and all patients with inadequate pre- or postoperative speech recordings were excluded, leaving a total of 85 patients in the study. INTERVENTIONS: Palate re-repairs, with radical dissection and retropositioning of the velar muscles, were performed using the operating microscope with intraoperative grading of anatomical and surgical findings. MAIN OUTCOME MEASURES: Pre- and postoperative perceptual speech assessments using the Cleft Audit Protocol for Speech (CAPS) score, measurement of velar function on lateral videofluoroscopy, and assessment of nasendoscopy recordings. RESULTS: There were significant improvements in hypernasality, nasal emission, and nasal turbulence and measures of velar function on lateral videofluoroscopy, with improvement in the closure ratio, velopharyngeal gap at closure, velar excursion, velar movement angle, and velar velocity. CONCLUSIONS: Palate re-repair has been shown to be effective in treating VPI following cleft palate repair, both in patients who have not had an intravelar veloplasty and those who have had a previous attempt at muscle dissection and retropositioning. Palate re-repair has a lower morbidity and is more physiological than a pharyngoplasty or pharyngeal flap.