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1.
Ear Hear ; 43(5): 1416-1425, 2022.
Article in English | MEDLINE | ID: mdl-35139052

ABSTRACT

OBJECTIVE: Hearing loss (HL) has been associated with cognitive impairment in high-income countries. However, no study has investigated this association in low- and middle-income countries. Therefore, our aim was to investigate the association between cognitive function and HL in the Brazilian Longitudinal Study of Adult Health. DESIGN: Cross-sectional analysis of Longitudinal Study of Adult Health (ELSA-Brasil) with 802 individuals (35-74 years old). Hearing was measured using pure-tone audiometry. A pure-tone average (s) of thresholds at 500, 1000, 2000, and 4000 Hz was calculated. HL was defined as a PTA above 25 dB in the better ear or either ear, as a categorical variable. Cognitive performance was measured using the Consortium to Establish a Registry for Alzheimer's Disease word list memory test, the semantic and phonemic verbal fluency (VF) tests, and the Trail Making test version B. To investigate the association between cognitive performance and HL, we used linear regression models adjusted for sociodemographic and clinical variables. RESULTS: Of the total of participants, 7.6% had HL. After adjustment for sociodemographic and health confounding variables, only VF was associated with HL; a 10 dB increase in the PTA in the better ear was associated with worse performance in the phonemic VF test (Ɵ = -0.115 [95% CI, -0.203 to -0.027], p = 0.01). We found a significant interaction between HL and age in the VF domain ( p = 0.01). HL was related to poor VF performance among older adults only. CONCLUSION: In a community-dwelling sample of most middle-aged adults, objectively measured HL was associated with lower VF. These results should be evaluated with caution, given the likelihood of residual confounding and the fact that only VF showed an association with HL.


Subject(s)
Deafness , Hearing Loss , Adult , Aged , Audiometry, Pure-Tone , Brazil/epidemiology , Cognition , Cross-Sectional Studies , Hearing Loss/epidemiology , Hearing Loss/psychology , Humans , Longitudinal Studies , Middle Aged
2.
Article in English | MEDLINE | ID: mdl-26157329

ABSTRACT

American English can be produced with two types of /s/: apical or laminal. These productions differ in that the apical gesture requires independent tongue tip elevation, and the laminal does not. Postglossectomy speakers, who have lost a unilateral portion of the tongue body along the outer edge, lose innervation to the tongue tip. We hypothesize that postglossectomy patients, even those with a preserved tongue tip, will be more likely to use laminal tongue shapes because of reduced control of the tongue tip. This study examines /s/ type, palate height, and related parameters in 24 control participants and 13 patients with lateral resections using cine-MRI and dental casts. Results of this dataset show that palate height affects choice of /s/ in control participants, but not in patients. Patients tend to use laminal /s/.

3.
Article in English | MEDLINE | ID: mdl-30135746

ABSTRACT

The human tongue has a complex architecture, consistent with its complex roles in eating, speaking and breathing. Tongue muscle architecture has been depicted in drawings and photographs, but not quantified volumetrically. This paper aims to fill that gap by measuring the muscle architecture of the tongue for 14 people captured in high-resolution 3D MRI volumes. The results show the structure, relationships and variability among the muscles, as well as the effects of age, gender and weight on muscle volume. Since the tongue consists of partially interdigitated muscles, we consider the muscle volumes in two ways. The functional muscle volume encompasses the region of the tongue served by the muscle. The structural volume halves the volume of the muscle in regions where it interdigitates with other muscles. Results show similarity of scaling across subjects, and speculate on functional effects of the anatomical structure.

4.
J Voice ; 31(4): 442-454, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28017460

ABSTRACT

OBJECTIVE: To compare vocal tract (VT) adjustments of dysphonic and non-dysphonic women before and after flexible resonance tube in water exercise (FRTWE) at rest and during phonation using magnetic resonance imaging. STUDY DESIGN: Prospective study. METHODS: Twenty women, aged 20-40 years, 10 dysphonic with vocal nodules (VNG) and 10 controls (CG), underwent four sets of sagittal VT MRI: two pre-FRTWE, at rest and during phonation, and two post-FRTWE, during phonation and at rest. The subjects performed 3 minutes of exercise. Nine parameters at rest and 21 during phonation were performed. RESULTS: Pre-FRTWE, eight significant differences were found, three at rest and five during phonation: at rest - laryngeal vestibule area, distance from epiglottis to pharyngeal posterior wall (PPW) and interarytenoid complex length were smaller in the VNG; during phonation - laryngeal vestibule area, angle between PPW and vocal fold (VF), epiglottis to PPW, and anterior commissure of the larynx to laryngeal posterior wall were smaller in the VNG; tongue area was larger in the VNG. Post-FRTWE, only three significant differences were found, two during phonation and one at rest: during phonation - angle between PPW and VF and the membranous portion of the VF length were smaller in the VNG; at rest - distance from epiglottis to PPW was smaller in the VNG. CONCLUSIONS: Results suggest that the habitual VT adjustments of dysphonic and non-dysphonic women are different at rest and during phonation. The FRTWE promoted positive VT changes in the VNG, reducing the intergroup differences.


Subject(s)
Dysphonia/physiopathology , Respiratory System/physiopathology , Voice Training , Adult , Dysphonia/therapy , Female , Humans , Magnetic Resonance Imaging , Prospective Studies , Respiratory System/diagnostic imaging , Young Adult
5.
J Voice ; 31(3): 389.e1-389.e8, 2017 May.
Article in English | MEDLINE | ID: mdl-27777057

ABSTRACT

OBJECTIVE: To determine the impact of jitter and shimmer on the degree of naturalness perception of synthesized vowels produced by acoustical simulation with glottal pulses (GP) and with solid model of the vocal tract (SMVT). STUDY DESIGN: Prospective study. METHODS: Synthesized vowels were produced in three steps: 1. Eighty GP were developed (20 with jitter, 20 with shimmer, 20 with jitter+shimmer, 20 without perturbation); 2. A SMVT was produced based on magnetic resonance imaging (MRI) from a woman during phonation-/ƎĀµ/ and using rapid prototyping technology; 3. Acoustic simulations were performed to obtain eighty synthesized vowels-/ƎĀµ /. Two experiments were performed. First Experiment: three judges rated 120 vowels (20 humans+80 synthesized+20% repetition) as "human" or "synthesized". Second Experiment: twenty PowerPoint slide sequences were created. Each slide had 4 synthesized vowels produced with the four perturbation condition. Evaluators were asked to rate the vowels from the most natural to the most artificial. RESULTS: First Experiment: all the human vowels were classified as human; 27 out of eighty synthesized vowels were rated as human, 15 of those were produced with jitter+shimmer, 10 with jitter, 2 without perturbation and none with shimmer. Second Experiment: Vowels produced with jitter+shimmer were considered as the most natural. Vowels with shimmer and without perturbation were considered as the most artificial. CONCLUSIONS: The association of jitter and shimmer increased the degree of naturalness of synthesized vowels. Acoustic simulations performed with GP and using SMVT demonstrated a possible method to test the effect of the perturbation measurements on synthesized voices.


Subject(s)
Acoustics , Glottis/physiology , Models, Anatomic , Speech Acoustics , Speech Intelligibility , Speech Perception , Voice Quality , Acoustic Stimulation , Adult , Dysphonia/physiopathology , Female , Glottis/diagnostic imaging , Humans , Judgment , Magnetic Resonance Imaging , Middle Aged , Phonation , Prospective Studies , Signal Processing, Computer-Assisted , Speech Production Measurement , Young Adult
6.
J Speech Lang Hear Res ; 59(3): 468-79, 2016 06 01.
Article in English | MEDLINE | ID: mdl-27295428

ABSTRACT

PURPOSE: Measuring tongue deformation and internal muscle motion during speech has been a challenging task because the tongue deforms in 3 dimensions, contains interdigitated muscles, and is largely hidden within the vocal tract. In this article, a new method is proposed to analyze tagged and cine magnetic resonance images of the tongue during speech in order to estimate 3-dimensional tissue displacement and deformation over time. METHOD: The method involves computing 2-dimensional motion components using a standard tag-processing method called harmonic phase, constructing superresolution tongue volumes using cine magnetic resonance images, segmenting the tongue region using a random-walker algorithm, and estimating 3-dimensional tongue motion using an incompressible deformation estimation algorithm. RESULTS: Evaluation of the method is presented with a control group and a group of people who had received a glossectomy carrying out a speech task. A 2-step principal-components analysis is then used to reveal the unique motion patterns of the subjects. Azimuth motion angles and motion on the mirrored hemi-tongues are analyzed. CONCLUSION: Tests of the method with a various collection of subjects show its capability of capturing patient motion patterns and indicate its potential value in future speech studies.


Subject(s)
Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging, Cine , Movement , Speech , Tongue/diagnostic imaging , Algorithms , Glossectomy , Humans , Magnetic Resonance Imaging, Cine/methods , Motion , Movement/physiology , Pattern Recognition, Automated , Principal Component Analysis , Speech/physiology , Tongue/physiology , Tongue/surgery , Tongue Neoplasms/surgery
7.
Med Image Anal ; 20(1): 198-207, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25487963

ABSTRACT

Imaging and quantification of tongue anatomy is helpful in surgical planning, post-operative rehabilitation of tongue cancer patients, and studying of how humans adapt and learn new strategies for breathing, swallowing and speaking to compensate for changes in function caused by disease, medical interventions or aging. In vivo acquisition of high-resolution three-dimensional (3D) magnetic resonance (MR) images with clearly visible tongue muscles is currently not feasible because of breathing and involuntary swallowing motions that occur over lengthy imaging times. However, recent advances in image reconstruction now allow the generation of super-resolution 3D MR images from sets of orthogonal images, acquired at a high in-plane resolution and combined using super-resolution techniques. This paper presents, to the best of our knowledge, the first attempt towards automatic tongue muscle segmentation from MR images. We devised a database of ten super-resolution 3D MR images, in which the genioglossus and inferior longitudinalis tongue muscles were manually segmented and annotated with landmarks. We demonstrate the feasibility of segmenting the muscles of interest automatically by applying the landmark-based game-theoretic framework (GTF), where a landmark detector based on Haar-like features and an optimal assignment-based shape representation were integrated. The obtained segmentation results were validated against an independent manual segmentation performed by a second observer, as well as against B-splines and demons atlasing approaches. The segmentation performance resulted in mean Dice coefficients of 85.3%, 81.8%, 78.8% and 75.8% for the second observer, GTF, B-splines atlasing and demons atlasing, respectively. The obtained level of segmentation accuracy indicates that computerized tongue muscle segmentation may be used in surgical planning and treatment outcome analysis of tongue cancer patients, and in studies of normal subjects and subjects with speech and swallowing problems.


Subject(s)
Magnetic Resonance Imaging/methods , Tongue/anatomy & histology , Databases, Factual , Game Theory , Humans , Muscles/anatomy & histology
8.
Article in English | MEDLINE | ID: mdl-26082883

ABSTRACT

Magnetic resonance imaging (MRI) is an essential tool in the study of muscle anatomy and functional activity in the tongue. Objective assessment of similarities and differences in tongue structure and function has been performed using unnormalized data, but this is biased by the differences in size, shape, and orientation of the structures. To remedy this, we propose a methodology to build a 3D vocal tract atlas based on structural MRI volumes from twenty normal subjects. We first constructed high-resolution volumes from three orthogonal stacks. We then removed extraneous data so that all 3D volumes contained the same anatomy. We used an unbiased diffeomorphic groupwise registration using a cross-correlation similarity metric. Principal component analysis was applied to the deformation fields to create a statistical model from the atlas. Various evaluations and applications were carried out to show the behaviour and utility of the atlas.

9.
J Appl Physiol (1985) ; 96(6): 2318-24; discussion 2317, 2004 Jun.
Article in English | MEDLINE | ID: mdl-14990556

ABSTRACT

To explore the mechanisms of speech articulation, which is one of the most sophisticated human motor skills controlled by the central nervous system, we investigated the force-generation dynamics of the human speech articulator muscles [orbicularis oris superior (OOS) and inferior (OOI) muscles of the lips]. Short-pulse electrical stimulation (300 micros) with approximately three or four times the sensation threshold intensity of each subject induced the muscle response. The responses of these muscles were modeled as second-order dynamics with a time delay (TD), and the model parameters [natural frequency (NF), damping ratio (DR), and TD] were identified with a nonlinear least mean squares method. The OOS (NF: 6.1 Hz, DR: 0.71, TD: 14.5 ms) and OOI (NF: 6.1 Hz, DR: 0.68, TD: 15.6 ms) showed roughly similar characteristics in eight subjects. The dynamics in the tongue (generated by combined muscles) also showed similar characteristics (NF: 6.1 Hz, DR: 0.68, TD: 17.4 ms) in two subjects. The NF was higher, and the DR was lower than results measured for arm muscles (NF: 4.25 Hz, DR: 1.05, TD: 23.8 ms for triceps long head), indicating that articulatory organs adapt for more rapid movement. In contrast, slower response dynamics was estimated when muscle force data by voluntarily contraction task were used for force-generation dynamics modeling. We discuss methodological problems in estimating muscle dynamics when different kinds of muscle contraction methods are used.


Subject(s)
Facial Muscles/physiology , Speech/physiology , Electric Stimulation , Humans , Kinetics , Motor Neurons/physiology , Muscle Contraction , Muscle, Skeletal/physiology , Stress, Mechanical
10.
Comput Med Imaging Graph ; 38(8): 714-24, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25155697

ABSTRACT

Dynamic MRI has been widely used to track the motion of the tongue and measure its internal deformation during speech and swallowing. Accurate segmentation of the tongue is a prerequisite step to define the target boundary and constrain the tracking to tissue points within the tongue. Segmentation of 2D slices or 3D volumes is challenging because of the large number of slices and time frames involved in the segmentation, as well as the incorporation of numerous local deformations that occur throughout the tongue during motion. In this paper, we propose a semi-automatic approach to segment 3D dynamic MRI of the tongue. The algorithm steps include seeding a few slices at one time frame, propagating seeds to the same slices at different time frames using deformable registration, and random walker segmentation based on these seed positions. This method was validated on the tongue of five normal subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of a total of 130 volumes showed an average dice similarity coefficient (DSC) score of 0.92 with less segmented volume variability between time frames than in manual segmentations.


Subject(s)
Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Movement/physiology , Pattern Recognition, Automated/methods , Speech/physiology , Tongue/anatomy & histology , Tongue/physiology , Algorithms , Humans , Image Interpretation, Computer-Assisted/methods , Reproducibility of Results , Sensitivity and Specificity , Subtraction Technique , User-Computer Interface
11.
J Speech Lang Hear Res ; 57(2): S626-36, 2014 Apr 01.
Article in English | MEDLINE | ID: mdl-24686470

ABSTRACT

PURPOSE Accurate tissue motion tracking within the tongue can help professionals diagnose and treat vocal tract-related disorders, evaluate speech quality before and after surgery, and conduct various scientific studies. The authors compared tissue tracking results from 4 widely used deformable registration (DR) methods applied to cine magnetic resonance imaging (MRI) with harmonic phase (HARP)-based tracking applied to tagged MRI. METHOD Ten subjects repeated the phrase "a geese" multiple times while sagittal images of the head were collected at 26 Hz, first in a tagged MRI data set and then in a cine MRI data set. HARP tracked the motion of 8 specified tissue points in the tagged data set. Four DR methods including diffeomorphic demons and free-form deformations based on cubic B-spline with 3 different similarity measures were used to track the same 8 points in the cine MRI data set. Individual points were tracked and length changes of several muscles were calculated using the DR- and HARP-based tracking methods. RESULTS The results showed that the DR tracking errors were nonsystematic and varied in direction, amount, and timing across speakers and within speakers. Comparison of HARP and DR tracking with manual tracking showed better tracking results for HARP except at the tongue surface, where mistracking caused greater errors in HARP than DR. CONCLUSIONS Tissue point tracking using DR tracking methods contains nonsystematic tracking errors within and across subjects, making it less successful than tagged MRI tracking within the tongue. However, HARP sometimes mistracks points at the tongue surface of tagged MRI because of its limited bandpass filter and tag pattern fading, so that DR has better success measuring surface tissue points on cine MRI than HARP does. Therefore, a hybrid method is being explored.


Subject(s)
Magnetic Resonance Imaging, Cine/methods , Models, Biological , Movement/physiology , Muscle Strength/physiology , Tongue/physiology , Adult , Algorithms , Female , Humans , Male , Middle Aged , Phonetics , Speech/physiology , Young Adult
12.
Rev. Salusvita (Online) ; 38(3): 567-579, 2019.
Article in Portuguese | LILACS | ID: biblio-1051377

ABSTRACT

IntroduĆ§Ć£o: Foi instituĆ­do Teste de Triagem Auditiva Neonatal Universal (TANU). CrianƧas podem passar no teste e apresentar surdez tardia ou progressiva ou, ainda, serem portadoras de perdas leves e moderadas que nĆ£o sĆ£o observadas. Objetivo: AtravĆ©s deste relato de caso, discutir os exames auditivos pertinentes em cada situaĆ§Ć£o e a orientaĆ§Ć£o dos profissionais de saĆŗde que primeiramente recebem estes pacientes. DescriĆ§Ć£o do Caso: O caso mostra a importĆ¢ncia da avaliaĆ§Ć£o da audiĆ§Ć£o para auxĆ­lio no diagnĆ³stico. Paciente foi encaminhado por quadro de atraso de linguagem e hipĆ³tese de perda auditiva. Apresentava dificuldades na interaĆ§Ć£o social e alteraƧƵes comportamentais. AvaliaĆ§Ć£o audiolĆ³gica foi normal, sendo feito diagnĆ³stico de transtorno de espectro autista (TEA). ComentĆ”rios: Pacientes com atraso e dificuldades na comunicaĆ§Ć£o podem ser difĆ­ceis de avaliar, visto que muitos dos exames auditivos sĆ£o subjetivos e dependem da interaĆ§Ć£o do examinador com a crianƧa. O caso relatado mostra uma das vĆ”rias situaƧƵes com que os profissionais podem se deparar e revela quais sĆ£o os exames adequados para uma avaliaĆ§Ć£o auditiva apropriada.


Introduction: Universal Newborn Hearing Screening (UNHS) Test was instituted to detect cases with higher probability of hearing loss. Children may pass the test and have late or progressive deafness or even mild and moderate losses that are not observed. Objective: To discuss, through this report of case, the pertinent auditory exams in each situation and the orientation of the health professionals who first receive these patients. Case Description: The case shows the importance of hearing evaluation for diagnostic assistance. Case 1 was referred for language delay and hypothesis of hearing loss. He presented difficulties in social interaction and behavioral changes. Audiological evaluation was normal, being diagnosed as Autistic Spectrum Disorder (ASD). Comments: Patients with delayed communication may be difficult to assess, since many of the auditory exams are subjective and depend on the interaction of the examiner with the child. The reported case presents one of the several situations that professionals may face and reveals what examinations are appropriate for an adequate auditory assessment.


Subject(s)
Developmental Disabilities , Speech Disorders , Neonatal Screening , Hearing Loss
13.
Article in English | MEDLINE | ID: mdl-24505742

ABSTRACT

Understanding the deformation of the tongue during human speech is important for head and neck surgeons and speech and language scientists. Tagged magnetic resonance (MR) imaging can be used to image 2D motion, and data from multiple image planes can be combined via post-processing to yield estimates of 3D motion. However, lacking boundary information, this approach suffers from inaccurate estimates near the tongue surface. This paper describes a method that combines two sources of information to yield improved estimation of 3D tongue motion. The method uses the harmonic phase (HARP) algorithm to extract motion from tags and diffeomorphic demons to provide surface deformation. It then uses an incompressible deformation estimation algorithm to incorporate both sources of displacement information to form an estimate of the 3D whole tongue motion. Experimental results show that use of combined information improves motion estimation near the tongue surface, a problem that has previously been reported as problematic in HARP analysis, while preserving accurate internal motion estimates. Results on both normal and abnormal tongue motions are shown.


Subject(s)
Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging, Cine/methods , Movement/physiology , Multimodal Imaging/methods , Robotics/methods , Tongue/anatomy & histology , Tongue/physiology , Algorithms , Humans , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Reproducibility of Results , Sensitivity and Specificity
14.
Proc IEEE Int Symp Biomed Imaging ; 2013: 816-819, 2013 Dec 31.
Article in English | MEDLINE | ID: mdl-24443691

ABSTRACT

Measuring the internal muscular motion and deformation of the tongue during natural human speech is of high interest to head and neck surgeons and speech language pathologists. A pipeline for calculating 3D tongue motion from dynamic cine and tagged Magnetic Resonance (MR) images during speech has been developed. This paper presents the result of a complete analysis of eleven subjects' (seven normal controls and four glossectomy patients) global tongue motion during speech obtained through MR imaging and processed through the tongue motion analysis pipeline. The data is regularized into the same framework for comparison. A generalized two-step principal component analysis is used to show the major difference between patients' and controls' tongue motions. A test is performed to demonstrate the ability of this process to distinguish patient data from control data and to show the potential power of quantitative analysis that the tongue motion pipeline can achieve.

15.
Proc IEEE Int Symp Biomed Imaging ; 2013: 1465-1468, 2013 Dec 31.
Article in English | MEDLINE | ID: mdl-24443699

ABSTRACT

Accurate segmentation is an important preprocessing step for measuring the internal deformation of the tongue during speech and swallowing using 3D dynamic MRI. In an MRI stack, manual segmentation of every 2D slice and time frame is time-consuming due to the large number of volumes captured over the entire task cycle. In this paper, we propose a semi-automatic segmentation workflow for processing 3D dynamic MRI of the tongue. The steps comprise seeding a few slices, seed propagation by deformable registration, random walker segmentation of the temporal stack of images and 3D super-resolution volumes. This method was validated on the tongue of two subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of 52 volumes showed an average dice similarity coefficient (DSC) score of 0.9 with reduced segmented volume variability compared to manual segmentations.

16.
IEEE Trans Biomed Eng ; 59(12): 3511-24, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23033324

ABSTRACT

Magnetic resonance images of the tongue have been used in both clinical studies and scientific research to reveal tongue structure. In order to extract different features of the tongue and its relation to the vocal tract, it is beneficial to acquire three orthogonal image volumes--e.g., axial, sagittal, and coronal volumes. In order to maintain both low noise and high visual detail and minimize the blurred effect due to involuntary motion artifacts, each set of images is acquired with an in-plane resolution that is much better than the through-plane resolution. As a result, any one dataset, by itself, is not ideal for automatic volumetric analyses such as segmentation, registration, and atlas building or even for visualization when oblique slices are required. This paper presents a method of superresolution volume reconstruction of the tongue that generates an isotropic image volume using the three orthogonal image volumes. The method uses preprocessing steps that include registration and intensity matching and a data combination approach with the edge-preserving property carried out by Markov random field optimization. The performance of the proposed method was demonstrated on 15 clinical datasets, preserving anatomical details and yielding superior results when compared with different reconstruction methods as visually and quantitatively assessed.


Subject(s)
Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Tongue/anatomy & histology , Algorithms , Brain/anatomy & histology , Brain/pathology , Computer Simulation , Databases, Factual , Humans , Markov Chains , Reproducibility of Results , Tongue/pathology , Tongue Neoplasms/pathology
17.
Proc SPIE Int Soc Opt Eng ; 83142012 Feb 04.
Article in English | MEDLINE | ID: mdl-27239084

ABSTRACT

Magnetic resonance (MR) images of the tongue have been used in both clinical medicine and scientific research to reveal tongue structure and motion. In order to see different features of the tongue and its relation to the vocal tract it is beneficial to acquire three orthogonal image stacks-e.g., axial, sagittal and coronal volumes. In order to maintain both low noise and high visual detail, each set of images is typically acquired with in-plane resolution that is much better than the through-plane resolution. As a result, any one data set, by itself, is not ideal for automatic volumetric analyses such as segmentation and registration or even for visualization when oblique slices are required. This paper presents a method of super-resolution reconstruction of the tongue that generates an isotropic image volume using the three orthogonal image stacks. The method uses preprocessing steps that include intensity matching and registration and a data combination approach carried out by Markov random field optimization. The performance of the proposed method was demonstrated on five clinical datasets, yielding superior results when compared with conventional reconstruction methods.

18.
IEEE Trans Med Imaging ; 31(2): 326-40, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21937342

ABSTRACT

Measuring the 3D motion of muscular tissues, e.g., the heart or the tongue, using magnetic resonance (MR) tagging is typically carried out by interpolating the 2D motion information measured on orthogonal stacks of images. The incompressibility of muscle tissue is an important constraint on the reconstructed motion field and can significantly help to counter the sparsity and incompleteness of the available motion information. Previous methods utilizing this fact produced incompressible motions with limited accuracy. In this paper, we present an incompressible deformation estimation algorithm (IDEA) that reconstructs a dense representation of the 3D displacement field from tagged MR images and the estimated motion field is incompressible to high precision. At each imaged time frame, the tagged images are first processed to determine components of the displacement vector at each pixel relative to the reference time. IDEA then applies a smoothing, divergence-free, vector spline to interpolate velocity fields at intermediate discrete times such that the collection of velocity fields integrate over time to match the observed displacement components. Through this process, IDEA yields a dense estimate of a 3D displacement field that matches our observations and also corresponds to an incompressible motion. The method was validated with both numerical simulation and in vivo human experiments on the heart and the tongue.


Subject(s)
Algorithms , Elasticity Imaging Techniques/methods , Heart/physiology , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Tongue/physiology , Computer Simulation , Elastic Modulus/physiology , Heart/anatomy & histology , Humans , Image Enhancement/methods , Models, Biological , Movement/physiology , Reproducibility of Results , Sensitivity and Specificity , Tongue/anatomy & histology
20.
Article in English | MEDLINE | ID: mdl-19217012

ABSTRACT

OBJECTIVE: The purpose of this study was to examine whether the diffusion tensor imaging (DTI) technique can be used as a modality to represent the structural deformation in the in vivo genioglossus (GG) muscle fibers with oral appliances (OAs). STUDY DESIGN: Three healthy subjects were recruited for the pilot study. A custom-made OA, which is modified from a tongue retaining device (TRD), was constructed for each subject before the DTI acquisitions. Recordings were made with and without OAs to compare the GG muscle fiber deformation. RESULT: DTI provided good resolution of tongue muscle fibers in vivo and successful isolation of each muscle fiber bundle. In particular, the GG muscle fiber deformation due to OAs was clearly visualized. CONCLUSIONS: This DTI technique may be used not only to identify the individual myoarchitecture, but also to assess muscle fiber deformations in vivo, such as constriction, dilatation, and rotation with OAs. Clinical studies for OSA patients will be the next step.


Subject(s)
Diffusion Magnetic Resonance Imaging/methods , Immobilization/instrumentation , Muscle Fibers, Skeletal/physiology , Muscle Tonus/physiology , Tongue/anatomy & histology , Adult , Female , Humans , Male , Pilot Projects
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