Intra-articular steroids for the treatment of coxarthrosis; a retrospective cohort study comparing three contrast techniques.

INTRODUCTION: Intra-articular steroid injections (IAS) are a treatment for coxarthrosis. This study examines the efficacy of three fluoroscopy-guided IAS contrast techniques for coxarthrosis: contrast-assisted (Iohexol), air arthrogram-assisted and blind (contrast/air free) and stratifies efficacy based on multiple patient variables. MATERIALS AND METHODS: A cohort of 307 hip IAS was retrospectively analysed over a four-year period. The primary outcome was efficacy of IAS between each technique group, defined by duration of symptomatic relief. The secondary outcome was efficacy based on multiple patient variables. Variables included age, BMI, gender, type of osteoarthritis, grade of osteoarthritis, smoking status, co-morbidity index and duration of pre-injection symptoms. Chi-squared, Pearson, One Way ANOVA and F-tests were used for statistical analysis. RESULTS: Total failure (< 1 week symptomatic relief) was 20% (contrast 20%, air 14%, blind 26%). >3 months of symptomatic relief was experienced by 35%, with the air arthrogram technique containing the largest proportion of IAS achieving > 3months of relief within its own group (contrast 35%, air 38%, blind 28%). Non-smokers experienced a longer duration of symptomatic relief in the air arthrogram group (p = 0.04). Older patients had a longer duration of symptomatic relief with the blind technique (p = < 0.001). There were no significant differences between the three techniques based on the other patient variables. CONCLUSION: Air arthrogram is an effective method of confirming injection placement in hip IAS for coxarthrosis and the use of a contrast agent (e.g., Iohexol) may not be required. Non-contrast techniques may produce longer duration of symptomatic relief in non-smokers and in older patients.

Submillimeter T1 atlas for subject-specific abnormality detection at 7T.

PURPOSE: Studies at 3T have shown that T1 relaxometry enables characterization of brain tissues at the single-subject level by comparing individual physical properties to a normative atlas. In this work, an atlas of normative T1 values at 7T is introduced with 0.6 mm isotropic resolution and its clinical potential is explored in comparison to 3T. METHODS: T1 maps were acquired in two separate healthy cohorts scanned at 3T and 7T. Using transfer learning, a template-based brain segmentation algorithm was adapted to ultra-high field imaging data. After segmenting brain tissues, volumes were normalized into a common space, and an atlas of normative T1 values was established by modeling the T1 inter-subject variability. A method for single-subject comparisons restricted to white matter and subcortical structures was developed by computing Z-scores. The comparison was applied to eight patients scanned at both field strengths for proof of concept. RESULTS: The proposed method for morphometry delivered segmentation masks without statistically significant differences from those derived with the original pipeline at 3T and achieved accurate segmentation at 7T. The established normative atlas allowed characterizing tissue alterations in single-subject comparisons at 7T, and showed greater anatomical details compared with 3T results. CONCLUSION: A high-resolution quantitative atlas with an adapted pipeline was introduced and validated. Several case studies on different clinical conditions showed the feasibility, potential and limitations of high-resolution single-subject comparisons based on quantitative MRI atlases. This method in conjunction with 7T higher resolution broadens the range of potential applications of quantitative MRI in clinical practice.

Event-driven enabled regression aided multi-loop control for SEC minimisation in SWRO desalination considering salinity variation.

This paper addresses the energy minimised operation of seawater reverse osmosis (SWRO) desalination process by simultaneous manipulation of feed pressure and reject valve opening. The specific energy consumption (SEC) analysis of SWRO desalination process for maintaining constant permeate flow during feed salinity variation is performed. The analysis is carried out to identify the suitable manipulating variables that can reduce the energy requirement for regulating permeate flow during feed salinity variation. Based on the analysis, a multi-loop control strategy using event-driven programming paradigm aided by regression based predictive model is proposed. The proposed methodology is more desirable than traditional event-driven multi-loop PID control due to smoother control transition and energy reduction. The investigation of SEC and analysis of proposed control strategy were performed using a previously validated dynamic model for SWRO desalination process. The simulation results show that the proposed methodology is superior to conventional PID control by enabling energy-minimised operation of RO process with significant reduction of feed pressure. The analysis shows that the proposed control approach reduces the feed pressure requirement by approximately 300 kPa during feed salinity variation.

Lung simulation to support non-invasive pulmonary blood flow measurement in Acute Respiratory Distress Syndrome in animals.

Patients undergoing mechanical lung ventilation are at risk of lung injury. A noninvasive bedside lung monitor may benefit these patients. The Inspired Sinewave Test (IST) can measure cardio-pulmonary parameters noninvasively. We propose a lung simulation to improve the measurement of pulmonary blood flow using IST. The new method was applied to 12 pigs' data before lung injury (control) and after lung injury (ARDS model). Results using the lung simulation shown improvements in correlation in both simulated data (R2 increased from 0.98 to 1) and pigs' data (R2 increased from <0.001 to 0.26). Paired blood flow measurements were performed by both the IST (noninvasive) and thermodilution (invasive). In the control group, the bias of the two methods was negligible (0.02L/min), and the limit of agreement was from -1.20 to 1.18 L/min. The bias was -0.68 L/min in the ARDS group and with a broader limit of agreement (-2.49 to 1.13 L/min).Clinical Relevance- the inspired sinewave test can be used to measure cardiac output noninvasively in mechanically ventilated subjects with and without acute respiratory distress syndrome.

Inferior vena cava revisited - Real-time flow MRI of respiratory maneuvers.

Recent MRI studies of blood flow in the inferior vena cava (IVC) resulted in findings which are inconsistent with earlier observations by invasive procedures - most likely because ECG-gated MRI techniques are unable to resolve dynamic adjustments due to respiration. The purpose of this work was to apply real-time phase-contrast MRI at 50 ms resolution to re-evaluate IVC flow in response to normal and deep breathing as well as breath holding and Valsalva maneuver (11 young healthy subjects). Real-time flow MRI relied on highly undersampled radial gradient-echo sequences and a model-based nonlinear inverse reconstruction. A frequency analysis of the predominant pulsatility classified IVC flow in individual subjects as "cardiac", "respiratory" or "mixed" type. Peak flow velocities during free breathing ranged from 30 to 58 cm s-1 , while flow rates varied from 15 to 37 ml s-1 . The subject-specific IVC flow pattern persists during deep breathing although the enhanced respiratory influence may shift subjects form "cardiac" to "mixed" or from "mixed" to "respiratory" type. Peak velocities increased relative to normal breathing but led to similar flow rates of 16 to 34 ml s-1 . Inspiration during deep breathing elicited brief periods of flow reversal in all subjects with mean peak velocities of -21 cm s-1 . The observation of only mildly flattened parabolic velocity distributions within the IVC indicated mostly laminar flow. Breath holding reduced blood flow velocities and rates by more than 40% on average, while Valsalva maneuvers completely abolished venous return. In conclusion, IVC blood flow is dominated by the acquired respiratory behavior of individual subjects and its pressure-induced alterations relative to cardiac pulsation. The responses to breath holding and Valsalva maneuver are in full agreement with previous invasive observations of reduced or even ceased flow, respectively.

Rapid and motion-robust volume coverage using cross-sectional real-time MRI.

PURPOSE: To develop a rapid and motion-robust technique for volumetric MRI, which is based on cross-sectional real-time MRI acquisitions with automatic advancement of the slice position. METHODS: Real-time MRI with a frame-by-frame moving cross-section is performed with use of highly undersampled radial gradient-echo sequences offering spin density, T1 , or T2 /T1 contrast. Joint reconstructions of serial images and coil sensitivity maps from spatially overlapping sections are accomplished by nonlinear inversion with regularization to the preceding section-formally identical to dynamic real-time MRI. Shifting each frame by 20% to 25% of the section thickness ensures 75% to 80% overlap of successive sections. Acquisition times of 40 to 67 ms allow for rates of 15 to 25 sections per second, while volumes are defined by the number of cross-sections times the section shift. RESULTS: Preliminary realizations at 3T comprise studies of the human brain, carotid arteries, liver, and prostate. Typically, coverage of a 90- to 180-mm volume at 0.8- to 1.2-mm in-plane resolution, 4- to 6-mm section thickness, and 0.8- to 1.5-mm section shift is accomplished within total measuring times of 4 to 6 seconds and a section speed of 15 to 37.5 mm per second. However, spatiotemporal resolution, contrast including options such as fat saturation and total measuring time are highly variable and may be adjusted to clinical needs. Promising volumetric applications range from fetal MRI to dynamic contrast-enhanced MRI. CONCLUSION: The proposed method allows for rapid and motion-robust volume coverage in a variety of imaging scenarios.

Tongue involvement in embouchure dystonia: new piloting results using real-time MRI of trumpet players.

BACKGROUND: The embouchure of trumpet players is of utmost importance for tone production and quality of playing. It requires skilled coordination of lips, facial muscles, tongue, oral cavity, larynx and breathing and has to be maintained by steady practice. In rare cases, embouchure dystonia (EmD), a highly task specific movement disorder, may cause deterioration of sound quality and reduced control of tongue and lip movements. In order to better understand the pathophysiology of this movement disorder, we use real-time MRI to analyse differences in tongue movements between healthy trumpet players and professional players with embouchure dystonia. METHODS: Real-time MRI videos (with sound recording) were acquired at 55 frames per second, while 10 healthy subjects and 4 patients with EmD performed a defined set of exercises on an MRI-compatible trumpet inside a 3 Tesla MRI system. To allow for a comparison of tongue movements between players, temporal changes of MRI signal intensities were analysed along 7 standardized positions of the tongue using a customised MATLAB toolkit. Detailed results of movements within the oral cavity during performance of an ascending slurred 11-note harmonic series are presented. RESULTS: Playing trumpet in the higher register requires a very precise and stable narrowing of the free oral cavity. For this purpose the anterior section of the tongue is used as a valve in order to speed up airflow in a controlled manner. Conversely, the posterior part of the tongue is much less involved in the regulation of air speed. The results further demonstrate that healthy trumpet players control movements of the tongue rather precisely and stable during a sustained tone, whereas trumpet players with EmD exhibit much higher variability in tongue movements. CONCLUSION: Control of the anterior tongue in trumpet playing emerges as a critical feature for regulating air speed and, ultimately, achieving a high-quality performance. In EmD the observation of less coordinated tongue movements suggests the presence of compensatory patterns in an attempt to regulate (or correct) pitch. Increased variability of the anterior tongue could be an objective sign of dystonia that has to be examined in further studies and extended to other brass instruments and may be also a potential target for therapy options.

Real-time multi-directional flow MRI using model-based reconstructions of undersampled radial FLASH - A feasibility study.

The purpose of this work was to develop an acquisition and reconstruction technique for two- and three-directional (2d and 3d) phase-contrast flow MRI in real time. A previous real-time MRI technique for one-directional (1d) through-plane flow was extended to 2d and 3d flow MRI by introducing in-plane flow sensitivity. The method employs highly undersampled radial FLASH sequences with sequential acquisitions of two or three flow-encoding datasets and one flow-compensated dataset. Echo times are minimized by merging the waveforms of flow-encoding and radial imaging gradients. For each velocity direction individually, model-based reconstructions by regularized nonlinear inversion jointly estimate an anatomical image, a set of coil sensitivities and a phase-contrast velocity map directly. The reconstructions take advantage of a dynamic phase reference obtained by interpolating consecutive flow-compensated acquisitions. Validations include pulsatile flow phantoms as well as in vivo studies of the human aorta at 3 T. The proposed method offers cross-sectional 2d and 3d flow MRI of the human aortic arch at 53 and 67 ms resolution, respectively, without ECG synchronization and during free breathing. The in-plane resolution was 1.5 × 1.5 mm2 and the slice thickness 6 mm. In conclusion, real-time multi-directional flow MRI offers new opportunities to study complex human blood flow without the risk of combining differential phase (i.e., velocity) information from multiple heartbeats as for ECG-gated data. The method would benefit from a further reduction of acquisition time and accelerated computing to allow for extended clinical trials.

Simultaneous dual-plane, real-time magnetic resonance imaging of oral cavity movements in advanced trombone players.

BACKGROUND: This paper describes the use of real-time magnetic resonance imaging to simultaneously obtain magnetic resonance imaging (MRI) videos in both a sagittal and coronal plane during the performance of a musical exercise in five advanced trombone players. METHODS: Dual-slice recordings were implemented in a frame-interleaved manner with 20 ms acquisitions per frame to achieve two interleaved videos at a rate of 25 frames per second. A customized MATLAB toolkit was used for the extraction of line profiles from MRI videos to quantify tongue movements associated with exercise performance from both perspectives. RESULTS: Across all subjects, the analyses revealed precise coupling of vertical movements of the dorsal tongue surface (DTS), viewed from a sagittal perspective, with reduction in the vertical and horizontal dimensions of the air channel formed between the DTS and the hard palate, viewed from a coronal perspective. The cross-correlation between these movements was very strong (mean R=0.967). CONCLUSIONS: These results demonstrate the unique utility of this dual-slice technology in describing the coordination of complex tongue movements occurring in two planes (i.e., three directions) simultaneously, lending a deeper understanding of lingual motor control during trombone performance.

Effect of Sagittal Dentoskeletal Discrepancies on the Vermilion Height and Lip Area.

OBJECTIVE: A frontal evaluation of the lips could provide important information during a routine clinical evaluation of facial aesthetics. There is a lack of ample evidence in the literature regarding variations in the vermilion height and lip area in various sagittal discrepancies when assessing facial aesthetics. The aim of this cross-sectional study was to evaluate and compare the vermilion height and lip area in dentoskeletal Class I, Class II, and Class III malocclusions. METHODS: Subjects included female patients divided into four groups (Angle's Class I bimaxillary proclination [Class I BMP], Class II Division I [Class II Div 1], Class III and Class I normal [Class I N]) with 36 samples each. Standardized frontal facial photographs were taken at rest and during a posed smile. Thirty-five landmarks on the upper and lower lips were identified for measurements of the vermilion height and lip area. A one-way analysis of variance was used to identify overall differences, and the post-hoc Bonferroni test was applied for multiple comparisons. RESULTS: Class III showed a significantly smaller upper-lip area and significantly higher ratios of the upper-to-lower lip vermilion height/area. The ratios displayed an increasing trend from the midline to the corners of the mouth. Class I BMP and Class II Div 1 had significantly larger upper and lower-lip areas. CONCLUSION: Morphology of the lips is significantly correlated with underlying anteroposterior dentoskeletal discrepancies. During a clinical examination, a critical frontal evaluation of the lips is important as it is apparently indicative of the underlying sagittal discrepancy, especially in skeletal Class III malocclusions.

Spinal CSF flow in response to forced thoracic and abdominal respiration.

BACKGROUND: Respiration-induced pressure changes represent a powerful driving force of CSF dynamics as previously demonstrated using flow-sensitive real-time magnetic resonance imaging (MRI). The purpose of the present study was to elucidate the sensitivity of CSF flow along the spinal canal to forced thoracic versus abdominal respiration. METHODS: Eighteen subjects without known illness were studied using real-time phase-contrast flow MRI at 3 T in the aqueduct and along the spinal canal at levels C3, Th1, Th8 and L3. Subjects performed a protocol of forced breathing comprising four cycles of 2.5 s inspiration and 2.5 s expiration. RESULTS: The quantitative results for spinal CSF flow rates and volumes confirm previous findings of an upward movement during forced inspiration and reversed downward flow during subsequent exhalation-for both breathing types. However, the effects were more pronounced for abdominal than for thoracic breathing, in particular at spinal levels Th8 and L3. In general, CSF net flow volumes were very similar for both breathing conditions pointing upwards in all locations. CONCLUSIONS: Spinal CSF dynamics are sensitive to varying respiratory performances. The different CSF flow volumes in response to deep thoracic versus abdominal breathing reflect instantaneous adjustments of intrathoracic and intraabdominal pressure, respectively. Real-time MRI access to CSF flow in response to defined respiration patterns will be of clinical importance for patients with disturbed CSF circulation like hydrocephalus, pseudotumor cerebri and others.

Tongue Position Variability During Sustained Notes in Healthy vs Dystonic Horn Players Using Real-Time MRI.

OBJECTIVE: Embouchure dystonia (EmD) is a variant of focal task-specific dystonia in musicians characterized by the loss of control in facial and oral muscles while controlling airflow into the mouthpiece of a wind or brass instrument. We compared tongue position variability (TPV) during sustained notes between healthy, elite horn players and horn players affected by EmD. METHODS: Real-time MRI films at 33.3 ms resolution were obtained from 8 healthy elite and 5 EmD horn players as they performed on a non-ferromagnetic horn at each of three different dynamic levels: pianissimo, mezzo forte, and fortissimo. Nine profile lines (3 from anterior, 3 from middle, and 3 from posterior oral cavity regions) were overlaid on each image using a customized MATLAB toolkit, and the variability of the dorsal tongue edge position was examined at each dynamic from temporal intensity profiles produced by MATLAB. RESULTS: Despite trends for more pronounced TPV (larger standard deviations) in the elite musicians (p=0.062), 2-way repeated measures ANOVA revealed no significant differences between groups. However, dynamic level significantly influenced TPV for all subjects, combined (p=0.048) and different regions of the oral cavity showed differing TPV (p<0.001). When only the most active region (anterior oral cavity) was included in the model, differences between groups reached statistical significance (elite > EmD, p<0.048), particularly at the fortissimo dynamic. We postulate that these differences may be due, in part, to a greater degree of generalized orofacial muscle tension in the EmD subjects that includes the tongue.

Multi-slice real-time MRI of temporomandibular joint dynamics.

OBJECTIVES: The purpose of this work was to improve the clinical versatility of high-speed real-time MRI studies of temporomandibular joint (TMJ) dynamics by simultaneous recordings of multiple MRI movies in different sections. METHODS: Real-time MRI at 3 T was realized using highly undersampled radial FLASH acquisitions and image reconstruction by regularized nonlinear inversion (NLINV). Multi-slice real-time MRI of two, three or four slices at 0.75 mm resolution and 6 to 8 mm thickness was accomplished at 50.0 ms, 33.3 ms or 25.5 ms temporal resolution, respectively, yielding simultaneous movies at 2 × 10, 3 × 10 or 4 × 10 frames per second in a frame-interleaved acquisition mode. Real-time MRI movies were evaluated by three blinded raters for visibility of the anterior and posterior border of disc, shape of the disk body and condyle head as well as movement of the disc and condyle (1 = excellent, 5 = no visibility). RESULTS: Effective delineation of the disk atop the mandibular condyle was achieved by T1-weighted images with opposed-phase water-fat contrast. Compared to 8 mm sections, multi-slice recordings with 6 mm thickness provided sharper delineation of relevant structures as confirmed by inter-rater evaluation. Respective dual-slice and triple-slice recordings of a single TMJ as well as dual-slice recordings of both joints (one slice per TMJ) received the highest visibility ratings of ≤ 2 corresponding to high confidence in diagnostic content. CONCLUSIONS: The improved access to TMJ dynamics by multi-slice real-time MRI will contribute to more effective treatment of temporomandibular disorders.

Quantification of spinal cord compression using T1 mapping in patients with cervical spinal canal stenosis - Preliminary experience.

BACKGROUND: Degenerative changes of the cervical spinal column are the most common cause of spinal cord lesions in the elderly. Conventional clinical, electrophysiological and radiological diagnostics of spinal cord compression are often inconsistent. MATERIALS AND METHODS: The feasibility and diagnostic potential of a novel T1 mapping method at 0.5 mm resolution and 4 s acquisition time was evaluated in 14 patients with degenerative cervical spinal canal stenosis (SCS) and 6 healthy controls. T1 mapping was performed in axial sections of the stenosis as well as above and below. All subjects received standard T2-weighted MRI of the cervical spine (including SCS-grading 0-III), electrophysiological and clinical examinations. RESULTS: Patients revealed significantly decreased T1 relaxation times of the compressed spinal cord within the SCS (912 ±â€¯53 ms, mean ±â€¯standard deviation) in comparison to unaffected segments above (1027 ±â€¯39 ms, p < .001) and below (1056 ±â€¯93 ms, p < .001). There was no difference in mean T1 in unaffected segments in patients (p = .712) or between segments in controls (p = .443). Moreover, T1 values were significantly lower in grade II (881 ±â€¯46 ms, p = .005) than in grade I SCS (954 ±â€¯29 ms). Patients with central conduction deficit tended to have lower T1 values within the SCS than patients without (909 ±â€¯50 ms vs 968 ±â€¯7 ms, p = .069). CONCLUSION: Rapid high-resolution T1 mapping is a robust MRI method for quantifying spinal cord compression in patients with cervical SCS. It promises additional diagnostic insights and warrants more extended patient studies.

Carotid artery flow as determined by real-time phase-contrast flow MRI and neurovascular ultrasound: A comparative study of healthy subjects.

BACKGROUND: The assessment of carotid artery flow by neurovascular ultrasound (nvUS) can be complemented by real-time phase-contrast (RT-PC) flow MRI which apart from quantitative flow parameters offers velocity distributions across the entire vessel lumen. MATERIALS AND METHODS: The feasibility and diagnostic potential of RT-PC flow MRI was evaluated in 20 healthy volunteers in comparison to conventional nvUS. RT-PC flow MRI at 40 ms temporal resolution and 0.8 mm in-plane resolution resulted in velocity maps with low phase noise and high spatiotemporal accuracy by exploiting respective advances of a recent nonlinear inverse model-based reconstruction. Peak-systolic velocities (PSV), end-diastolic velocities (EDV), flow volumes and comprehensive velocity profiles were determined in the common, internal and external carotid artery on both sides. RESULTS: Flow characteristics such as pulsatility and individual abnormalities shown on nvUS could be reproduced and visualized in detail by RT-PC flow MRI. PSV to EDV differences revealed good agreement between both techniques, mean PSV and EDV were significantly lower and flow volumes were higher for MRI. CONCLUSION: Our findings suggest that RT-PC flow MRI adds to clinical diagnostics, e.g. by alterations of dynamic velocity distributions in patients with carotid stenosis. Lower PSV and EDV values than for nvUS mainly reflect the longer MRI acquisition time which attenuates short peak velocities, while higher flow volumes benefit from a proper assessment of the true vessel lumen.

Intra- and interobserver variability in the diagnosis of GERD by real-time MRI.

The purpose of this study was to assess the reproducibility of functional and anatomical parameters of swallowing events as determined by real-time MRI at 40 ms temporal resolution (25 frames per second). Twenty-three consecutive patients with gastroesophageal reflux disease (GERD) underwent real-time MRI of the gastroesophageal junction at 3.0 T. Real-time MRI was based on highly undersampled radial fast low angle shot (FLASH) acquisitions with iterative image reconstruction by regularized nonlinear inversion (NLINV). MRI movies visualized the esophageal transport of a pineapple juice bolus, its passage through the gastroesophageal junction and functional responses during a Valsalva maneuver. His-angle, sphincter position, sphincter length and sphincter transit time were assessed by two radiologists. Interobserver and intraobserver intraclass correlation coefficients (ICC) were evaluated and Bland-Altman plots were constructed to assess the observer agreement. Interobserver agreement was excellent for sphincter transit time (ICC = 0.92), His-angle (ICC = 0.93), His-angle during Valsalva maneuver (ICC = 0.91) and sphincter-to-diaphragm distance (ICC = 0.98). Sphincter length and oesophageal diameter showed good interobserver agreement (ICC = 0.62 and ICC = 0.70). Intraobserver agreement was good for sphincter length (ICC = 0.80) and excellent for sphincter transit time, His-angle and His-angle during Valsalva maneuver, sphincter-to-diaphragm distance, and esophageal diameter (ICC = 0.91; ICC = 0.97; ICC = 0.97; ICC = 0.998; ICC = 0.93). All functional parameters of the gastroesophageal junction had good to excellent reproducibility. Visual assessment of Bland Altman plots did not reveal any systematic interobserver bias. In conclusion, the visualization of swallowing events by real-time MRI has a high potential for clinical application in gastroesophageal reflux disease.

Respiration and the watershed of spinal CSF flow in humans.

The dynamics of human CSF in brain and upper spinal canal are regulated by inspiration and connected to the venous system through associated pressure changes. Upward CSF flow into the head during inspiration counterbalances venous flow out of the brain. Here, we investigated CSF motion along the spinal canal by real-time phase-contrast flow MRI at high spatial and temporal resolution. Results reveal a watershed of spinal CSF dynamics which divides flow behavior at about the level of the heart. While forced inspiration prompts upward surge of CSF flow volumes in the entire spinal canal, ensuing expiration leads to pronounced downward CSF flow, but only in the lower canal. The resulting pattern of net flow volumes during forced respiration yields upward CSF motion in the upper and downward flow in the lower spinal canal. These observations most likely reflect closely coupled CSF and venous systems as both large caval veins and their anastomosing vertebral plexus react to respiration-induced pressure changes.

Diagnosis of disk displacement using real-time MRI: Clinical report of two patients.

The clinical application of real-time magnetic resonance imaging (MRI) for the diagnosis of temporomandibular joint disk displacement (DD) with and without reduction is presented. In 2 patients with presumed DD, real-time MRI at 15 frames per second was performed during the natural opening and closing of the mouth. In one patient unilateral DD with reduction and in the other patient bilateral DD without reduction were observed. In contrast with conventional static MRI, real-time MRI moving images of temporomandibular joint DD offer comprehensive information about the dynamics of all involved structures, which in turn promises more reliable diagnoses. Real-time MRI is more rapid, more reliable, more informative, and less stressful for patients with temporomandibular disorders (TMDs).