Academic literature on the topic 'Diaphragm fluoroscopy'

To develop an accurate method to measure the volume displaced by diaphragm motion (ΔVdi) breath by breath, we compared ΔVdi measured by a previously evaluated biplanar radiographic method (Singh B, Eastwood PR, and Finucane KE. J Appl Physiol 91: 1913–1923, 2001) at several lung volumes during vital capacity inspirations in 10 healthy and nine hyperinflated subjects with 1) ΔVdi measured from the same chest X-rays by two previously described uniplanar methods (Petroll WM, Knight H, and Rochester DF. J Appl Physiol 69: 2175–2182, 1990; Verschakelen JA, Deschepper K, and Demendts M. J Appl Physiol 72: 1536–1540, 1992) and a proposed method that considered actual cross-sectional shape of the rib cage and spinal volume (ΔVdiS); and 2) ΔVdiS measured by lateral fluoroscopy in the same 10 healthy subjects. Relative to biplanar ΔVdi, ΔVdiS values from lateral chest X-rays and fluoroscopy were not different, whereas ΔVdi values of Petroll et al. and Verschakelen et al. were increased by (means ± SD) 1.98 ± 1.59 and 1.16 ± 0.82 liters, respectively (both P< 0.001). During quiet breathing, ΔVdiS by lateral fluoroscopy was 66 ± 16% of tidal volume and similar to that between functional residual capacity and one-half inspiratory capacity by the biplanar radiographic method. We conclude that accurate breath-by-breath measurements of ΔVdi can be made by using lateral fluoroscopy.

In eight healthy volunteers we simultaneously measured the axial diaphragmatic motion by fluoroscopy and the cross-sectional area changes of the rib cage (RC) and abdomen (ABD) by Respitrace (RIP) during semistatic vital capacities (VC). We found that, if the fluoroscopic axial displacement of the posterior part of the diaphragm between residual volume (RV) and total lung capacity (TLC) is considered equal to 100%, the movement of the middle part is 90%, whereas that of the anterior part is only approximately 60%; the ratio of the axial displacements to mouth volume, furthermore, decreases at high lung volumes, especially for the anterior part. The RIP signal is nearly linearly related to mouth volume, but the contribution of the RC (delta RC) progressively increases (and is approximately 80% RIP at TLC), whereas the volume contribution of the ABD (delta ABD) levels off (to 20% RIP at TLC). The diaphragmatic volume displacement calculated from the theoretical analysis described by Mead and Loring also levels off at high volumes similarly as the ABD but is approximately 50% RIP at TLC. Finally, the axial movements of the three parts of the diaphragm are linearly related to the RC and ABD cross-sectional-area changes (r 0.91–0.97) and are even significantly better correlated with the “calculated” diaphragmatic volume displacement.

During physiological spontaneous breathing maneuvers, the diaphragm displaces volume while maintaining curvature. However, with maximal diaphragm activation, curvature decreases sharply. We tested the hypotheses that the relationship between diaphragm muscle shortening and volume displacement (VD) is nonlinear and that curvature is a determinant of such a relationship. Radiopaque markers were surgically placed on three neighboring muscle fibers in the midcostal region of the diaphragm in six dogs. The three-dimensional locations were determined using biplanar fluoroscopy and diaphragm VD, curvature, and muscle shortening were computed in the prone and supine postures during spontaneous breathing (SB), spontaneous inspiration efforts after airway occlusion at lung volumes ranging from functional residual capacity (FRC) to total lung capacity, and during bilateral maximal phrenic nerve stimulation at those same lung volumes. In supine dogs, diaphragm VD was approximately two- to three-fold greater during maximal phrenic nerve stimulation than during SB. The contribution of muscle shortening to VD nonlinearly increases with level of diaphragm activation independent of posture. During submaximal diaphragm activation, the contribution is essentially linear due to constancy of diaphragm curvature in both the prone and supine posture. However, the sudden loss of curvature during maximal bilateral phrenic nerve stimulation at muscle shortening values greater than 40% (ΔL/LFRC) causes a nonlinear increase in the contribution of muscle shortening to diaphragm VD, which is concomitant with a nonlinear change in diaphragm curvature. We conclude that the nonlinear relationship between diaphragm muscle shortening and its VD is, in part, due to a loss of its curvature at extreme muscle shortening.

Muscle shortening and volume displacement (VD) are critical determinants of the pressure-generating capacity of the diaphragm. The present study was designed to test the hypothesis that diaphragm VD is heterogeneous and that distribution of VD is dependent on regional muscle shortening, posture, and the level of muscle activation. Radioopaque markers were sutured along muscle bundles of the peritoneal surface of the crural, dorsal costal, midcostal, and ventral costal regions of the left hemidiaphragm in four dogs. The markers were followed by biplanar video fluoroscopy during quiet spontaneous breathing, passive inflation to total lung capacity (TLC), and inspiratory efforts against an occluded airway at three lung volumes spanning the vital capacity [functional residual capacity, functional residual capacity + ½ inspiratory capacity, and TLC in both the prone and supine postures]. Our data show the ventral costal diaphragm had the largest VD and contributed nearly two times to the total diaphragm VD compared with the dorsal costal portion. In addition, the ventral costal diaphragm contributed nearly half of the total VD in the prone position, whereas it only contributed a quarter of the total VD in the supine postition. During efforts against an occluded airway and during passive inflation to TLC in the supine position, the crural diaphragm displaced volume equivalent to that of the midcostal portion. Regional muscle shortening closely matched regional VD. We conclude that the primary force generator of the diaphragm is primarily dominated by the contribution of the ventral costal region to its VD.

Radiopaque markers were attached at 1- to 2-cm intervals along three nearby muscle bundles to cover rectangular regions of the mid-costal diaphragms of seven dogs. The markers were tracked by biplane video fluoroscopy during spontaneous breathing (SB), mechanical ventilation with the same tidal volume (MV), and at inflation to total lung capacity (TLC) in the prone and supine positions. The three-dimensional positions of the markers at functional residual capacity (FRC), at end inspiration during SB and MV, and at TLC were determined, and the strains in the plane of the diaphragm relative to FRC were calculated. The principal strains were found to lie nearly along the muscle bundle direction and perpendicular to it. The principal strains along the muscle bundles, which describe muscle shortening, were uniform among the three bundles and uniform along the bundle for MV. For SB, in the prone and supine positions, shortening was approximately 30% greater in the middle of the bundle than near the central tendon and chest wall. Although the tidal volumes were the same for SB and MV, the shortening was larger for SB. The strains perpendicular to the bundle direction were not significantly different from zero. It appears that, for the loads that occur during tidal breathing, the diaphragm is inextensible in the direction perpendicular to the muscle direction. There is a very small displacement of the costal diaphragm at its insertion on the chest wall. The displacement at the central tendon is primarily a result of muscle shortening and rotation of the arc of the muscle around its insertion on the chest wall.

We tested the hypothesis that diaphragm muscle shortening modulates volume displacement and kinematics of the lower rib cage in dogs and that posture and mode of ventilation affect such modulation. Radiopaque markers were surgically attached to the lower three ribs of the rib cage and to the midcostal region of the diaphragm in six dogs of ∼8 kg body masses, and the locations of these markers were determined by a biplane fluoroscopy system. Three-dimensional software modeling techniques were used to compute volume displacement and surface area of the midcostal diaphragm and the lower three ribs during quiet spontaneous breathing, mechanical ventilation, and bilateral phrenic nerve stimulation at different lung volumes spanning the vital capacity. Volume displaced by the diaphragm relative to that displaced by the lower ribs is disproportionately greater under mechanical ventilation than during spontaneous breathing in the supine position ( P < 0.05). At maximal stimulation, diaphragm volume displacement grows disproportionately larger than rib volume displacement as lung volume increases ( P < 0.05). Surface area of both the diaphragm and the lower ribs during maximal stimulation of the diaphragm is reduced compared with that at spontaneous breathing ( P < 0.05). In the prone posture, mechanical ventilation results in a smaller change in diaphragm surface area than spontaneous breathing ( P < 0.05). Our data demonstrate that during inspiration the lower rib cage moves not only through the pump- and bucket-handle motion, but also rotates around the spine. Taken together, these data support the observation that the kinematics of the lower rib cage and its mechanical interaction with the diaphragm are more complex than previously known.

We measured the transdiaphragmatic pressure (Pdi) during bilateral phrenic nerve stimulation and evaluated the determinants of its change with lung volume, chest wall geometry, and respiratory system impedance in supine dogs. Four rows of radiopaque markers were sewn onto muscle bundles of the costal and crural diaphragm between their origin on the central tendon and their insertion on the rib cage and spine. The length of the diaphragm (L) was determined from the projection images of marker rows using biplane fluoroscopy. Measurements were made at lung volumes between total lung capacity and functional residual capacity before and after the infusion of Ringer lactate solution into the abdominal cavity. In contrast to relaxation, during tetanic stimulation the active lengths of the muscle bundles were similar at all volumes, but the diaphragm assumed different shapes. Although the small differences in active muscle length with volume and liquid loads are consistent with only small changes in muscle force output, Pdi varied by a factor of greater than or equal to 5. There was no single L/Pdi curve that fitted all data during 50-Hz stimulations. We conclude that under these experimental conditions Pdi is not a unique measure of the force produced by the diaphragm and that lung volume, chest wall geometry, and respiratory system impedance are important determinants of the mechanical efficiency of the diaphragm as a pressure generator.

A 57 year old woman was presented to the emergency department with upper abdominal pain and left sided chest discomfort. No cardiac or pulmonary cause could be determined and the patient underwent upper gastrointestinal endoscopy. Inversion of the scope to the fundus and subsequent fluoroscopy revealed a diaphragmatic hernia with a large herniation of the gastric fundus. Immediate laparotomy showed a 3 cm orifice of the diaphragm. The orifice was widened and a partial necrosis of the incarcerated fundus was resected. The patient recovered fully and was discharged 12 days after laparotomy.

During semistatic inspiratory and expiratory vital capacity (VC) maneuvers, axial motion of the diaphragm was measured by lateral fluoroscopy and was compared with diaphragmatic volume displacement. Axial motion was measured at the anterior, middle, and posterior parts of the diaphragm, and the mean of these measurements was used. The volume displacement was calculated in two ways: first, from respiratory inductive plethysmograph-(Respitrace) derived cross-sectional area changes of rib cage and abdomen (Vdi,RIP) by means of a theoretical analysis described by Mead and Loring (J. Appl. Physiol. 53: 750–755, 1982) and, second, from fluoroscopically measured changes in position and anteroposterior surface of the diaphragm (Vdi,F). A very good linear relationship was found between Vdi,RIP and Vdi,F during inspiration as well as expiration (r greater than 0.95), indicating that the analysis of Mead and Loring was valid in the conditions of the present study. The diaphragmatic volume displacement (active or passive) accounted for 50–60% of VC. A very good linear relationship was also found between mean axial motion and volume displacement of the diaphragm measured with both methods during inspiration and expiration (r greater than 0.98). Our data suggest that, over the VC range, diaphragmatic displacement functionally can be represented by a pistonlike model, although topographically and anatomically it does not behave as a piston.

Background Diaphragmatic excursion during spontaneous ventilation (SV) in normal supine volunteers is greatest in the dependent regions (bottom). During positive pressure ventilation (PPV) after anesthesia and neuromuscular blockade and depending on tidal volume, the nondependent region (top) undergoes the greatest excursion, or the diaphragm moves uniformly. The purpose of this study was to compare diaphragmatic excursion (during SV and PPV) in patients with chronic obstructive pulmonary disease (COPD) with patients having normal pulmonary function. Methods Twelve COPD patients and 12 normal control subjects were compared. Cross-table diaphragmatic fluoroscopy was performed while patients breathed spontaneously. After anesthetic induction and pharmacologic paralysis and during PPV, diaphragmatic fluoroscopy was repeated. For analytic purposes, the diaphragm was divided into three segments: top, middle, and bottom. Percentage of excursion of each segment during SV and PPV in normal subjects was compared with the percentage of excursion of each segment in patients with COPD. Results There was no significant difference in the pattern of regional diaphragmatic excursion (as a percentage of total excursion)-top, middle, bottom-when comparing COPD patients with control subjects during SV and PPV. In the control subjects, regional diaphragmatic excursion was 16 +/- (5), 33 +/- (5), 51 +/- (4) during SV and 49 +/- (13), 32 +/- (6), 19 +/- (9) during PPV. In COPD patients, regional diaphragmatic excursion was 18 +/- (7), 34 +/- (5), 49 +/- (7) during SV and 47 +/- (10), 32 +/- (6), 21 +/- (9) during PPV. Conclusion Regional diaphragmatic excursion in patients with COPD during SV and PPV is similar to that in persons with normal pulmonary function.

[Truncated abstract] The function of the diaphragm as a volume pump has not been adequately evaluated because there are no accurate methods to measure the volume displaced by diaphragm motion (ΔVdi). As a consequence, the work done, power output and efficiency of the diaphragm have not been measured. Efficiency of the diaphragm could be measured by relating the power output of the diaphragm to its neural activation. The aims of this thesis were to (a) develop a new biplanar radiographic method to measure ΔVdi and use this to evaluate the effect of costophrenic fibrosis and emphysema on ΔVdi, (b) develop a new fluoroscopic method to enable breath-by-breath measurements of ΔVdi, (c) evaluate a method for quantifying neural activation of the diaphragm, and (d) combine measurements of transdiaphragmatic pressure, ΔVdi, inspiratory duration and neural activation of the diaphragm to quantify the neuromechanical efficiency of the diaphragm

In this work several algorithms for diaphragm detection in 2D views of cone-beam computed tomography (CBCT) raw data are developed. These algorithms are tested on 21 Siemens megavoltage CBCT scans of lungs and the result is compared against the diaphragm apex identified by human experts. Among these algorithms dynamic Hough transform is sufficiently quick and accurate for motion determination prior to radiation therapy. The diaphragm was successfully detected in all 21 data sets, even for views with poor image quality and confounding objects. Each CBCT scan analysis (200 frames) took about 38 seconds on a 2.66 GHz Intel quad-core 2 CPU. The average cranio-caudal position error was 1.707 ± 1.117 mm. Other directions were not assessed due to uncertainties in expert identification.

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Fluoroscopy is considered the most reliable method for evaluating diaphragmatic mobility, yet most existing methods for measuring diaphragmatic mobility using fluoroscopy are complex. Thus, this study proposes a new way to measure diaphragmatic mobility. The objective of this study was to evaluate the validity and reliability of the evaluation method of diaphragmatic motion using fluoroscopy by digital radiography; and to compare diaphragmatic mobility on the right side to the left side and diaphragmatic mobility between male and female subjects. 26 adults between 20 and 47 were evaluated, according to the parameters: anthropometry, pulmonary function test and diaphragm mobility. The evaluation of diaphragm mobility by means of the fluoroscopy by digital radiography method was conducted randomly by two raters (A and B). Concurrent validity was analyzed by Pearson coefficient correlation (r) ando the intraclass correlation coefficient (ICC[2,1]) and with confidence interval of 95% (CI) to evaluate the relationship and agreement between digital diaphragmatic mobility (MDdig) and distance (MDdist). Intra and interraters reliability of the diaphragmatic motion measurement was determined using the ICC and with CI 95%. The Bland & Altman plot for better visualization of the data was used. The high correlation was found between DMdig and DMdist for mobility of the right hemidiaphragm (RH) (r = 0.97, p = 0.00) and the left (LH) (r = 0.88, p = 0.00). There was good reliability for mobility in both hemidiaphragms (RH: ICC[2,1] = 0.98, CI95% = 0.96 to 0.99; LF: ICC[2,1] = 0.93, CI95% = 0.84 to 0.97). The first assessment of interrater reliability showed a high correlation for right hemidiaphragm mobility and moderate correlation for left hemidiaphragm mobility (ICC[2,1 = 0.89, CI95% =0.76 to 0.95 and ICC[2,1 = 0.73, CI95% = 0.48 to 0.87 respectively). The second assessment, showed a good reliability for right and left hemidiaphragm mobility for rater A (ICC[2,1 = 0.83, CI95% = 0.66 to 0.92 and ICC[2,1 = 0.86, CI95% = 0.70 to 0.93, respectively) and for the rater B (ICC[2,1 = 0.89, CI95% = 0.76 to 0.95) (ICC[2,1 = 0.83, CI95% = 0.65 to 0.92) respectively. There was no statistically significant difference in the mobility measured between the right and left hemidiaphragms, and between mobility measured in men and women. The evaluation of diaphragmatic motion using fluoroscopy for digital radiography proved to be a valid and reliable method.
A fluoroscopia é considerada o método mais confiável para avaliar a mobilidade diafragmática, contudo a maioria dos métodos existentes para mensurar a mobilidade diafragmática por meio da fluoroscopia é complexo. Diante disso, este estudo propõe uma nova forma para mensurar a mobilidade diafragmática. O objetivo do estudo foi avaliar a validade e a confiabilidade de um novo método de avaliação da mobilidade diafragmática utilizando a fluoroscopia por radiografia digital e comparar a mobilidade diafragmática do lado direito com a do lado esquerdo e a mobilidade diafragmática entre os indivíduos do sexo masculino e feminino. Foram avaliados 26 adultos, entre 20 e 47 anos, segundo os parâmetros: antropometria, prova de função pulmonar e mobilidade do diafragma. A avaliação da mobilidade diafragmática por meio do método da fluoroscopia por radiografia digital foi realizada, de forma aleatória, por dois observadores (A e B). A validade concorrente foi analisada pelo coeficiente de correlação de Perason (r) e pelo coeficiente de correlação intraclasse (CCI) e com intervalo de confiança de 95% (IC) para avaliar a relação e a concordância entre as mobilidades diafragmática digital (MDdig) e distância(MDdist). A confiabilidade inter e intra-observadores da mensuração da mobilidade diafragmática foi determinada pelo CCI e com IC 95%. Foi utilizada a disposição gráfica de Bland-Altman para melhor visualização dos dados. Foi encontrada alta correlação entre a MDdig e a MDdist (r= 0,97, p= 0.00) e boa confiabilidade na mobilidade dos hemidiafragmas dos dois métodos (Hemiafragma direito: CCI[2,1] = 0,98, IC95% = 0,96-0,99; Hemidiafragma esquerdo: CCI[2,1] = 0,93, IC95% = 0,84-0,97). Houve boa confiabilidade interobservador na mobilidade do hemidiafragma direito (CCI = 0,89, IC95% = 0,76-0,95) e moderada no esquerdo (CCI = 0,73, IC95% = 0,48-0,87) na 1ª avaliação. Na 2ª avaliação, houve boa confiabilidade nos hemidiafragmas direito (CCI = 0,84, IC95% = 0,68-0,93) e esquerdo (CCI = 0,78, IC95% = 0,56-0,89), respectivamente. Houve boa confiabilidade intraobservador na mobilidade dos hemidiafragmas direito (CCI = 0,83, IC95% = 0,66-0,92) e esquerdo (CCI = 0,86, IC95% = 0,70- 0,93) para o observador A e para o observador B (CCI = 0,89, IC95% = 0,76-0,95) e (CCI = 0,83, IC95% = 0,65-0,92), respectivamente. Não houve diferença estatisticamente significante para a mobilidade mensurada entre os hemidiafragmas direito e esquerdo, e entre a mobilidade aferida nos homens e nas mulheres. A avaliação da mobilidade diafragmática utilizando a fluoroscopia por radiografia digital demonstrou ser um método válido e confiável.

The chapter titled imaging modalities describes various methods of imaging the thorax. Imaging of patients presenting with thoracic complaints typically begins with chest radiography. Ambulatory patients should undergo posteroanterior (PA) and lateral chest radiographs. Anteroposterior (AP) chest radiography should be reserved for debilitated, critically ill and traumatized patients. Special chest radiographic projections such as decubitus chest radiography may be employed for specific indications. Chest CT is the imaging study of choice for evaluating most abnormalities found on radiography. Contrast-enhanced chest CT is optimal for evaluation of vascular abnormalities, the hila and some mediastinal lesions. CT angiography is routinely employed in patients with suspected pulmonary thromboembolism or acute aortic syndromes. High-resolution chest CT is reserved for the evaluation of diffuse infiltrative lung disease and often includes expiratory and prone imaging. FDG PET/CT is increasingly employed in the assessment of patients with malignancy for the purposes of initial staging and post therapy re-staging of affected patients. Ventilation/perfusion scintigraphy is used in the assessment of pulmonary thromboembolism. Additional thoracic imaging techniques include: Fluoroscopy for evaluation of the diaphragm, and ultrasound for evaluation of the thyroid and the pleural space.