Normal Thorax Research Articles

Attenuation Tomography Using Low-Frequency Ultrasound for Thorax Imaging: Feasibility Study.

Low-frequency ultrasound can permeate human thorax and can be applied in functional imaging of the respiratory system. In this study, we investigate the transmission of low-frequency ultrasound through the human thorax and propose a waveform matching method to track the changes in the transmission signal during subject's respiration. The method's effectiveness is validated through experiments involving ten human subjects. Furthermore, the experimental findings indicate that the traveltime of the first-arrival signal remains consistent throughout the respiratory cycle. Leveraging this observation, we introduce an algorithm for ultrasound thorax attenuation factor differential imaging. By computing the paths and energy variation of the first-arrival signal from the received waveform, the algorithm reconstructs the distribution of attenuation factor differences between two different thorax states, providing insights into the functional status of the respiratory system. Numerical experiments, using both normal thorax and defective thorax models, confirm the algorithm's feasibility and its robustness against noise, variations in transducer position and orientation. These results highlight the potential of low-frequency ultrasound for bedside, continuous monitoring of human respiratory system through functional imaging.

Image Human Thorax Using Ultrasound Traveltime Tomography with Supervised Descent Method

The change of acoustic velocity in the human thorax reflects the functional status of the respiratory system. Imaging the thorax’s acoustic velocity distribution can be used to monitor the respiratory system. In this paper, the feasibility of imaging the human thorax using ultrasound traveltime tomography with a supervised descent method (SDM) is studied. The forward modeling is computed using the shortest path ray tracing (SPR) method. The training model is composed of homogeneous acoustic velocity background and a high-velocity rectangular block moving in the domain of interest (DoI). The average descent direction is learned from the training set. Numerical experiments are conducted to verify the method’s feasibility. Normal thorax model experiment proves that SDM traveltime tomography can efficiently reconstruct thorax acoustic velocity distribution. Numerical experiments based on synthetic thorax model of pleural effusion and pneumothorax show that SDM traveltime tomography has good generalization ability and can detect the change of acoustic velocity in human thorax. This method might be helpful for the diagnosis and evaluation of respiratory diseases.

PO-618-03 REDUCTION IN DEFIBRILLATION THRESHOLD BY MODIFICATIONS TO THE SUBCUTANEOUS ICD COIL

Subcutaneous Implantable Cardioverter Defibrillators (S-ICDs) generally have higher defibrillation thresholds (DFTs) than transvenous ICDs, necessitating larger S-ICD generators and with S-ICD VF conversion testing recommended at implantation. We sought to determine whether modifications to the S-ICD coil configuration or characteristics would reduce DFTs compared to the standard S-ICD coil based on a computer model of defibrillation. We utilized a computer model built from MRI images of a normal thorax and simulation of electrical fields generated by defibrillation. The specific electrical properties of tissues and organs were assigned, as well as other characteristics of the shock circuit, with DFT defined as energy required to achieve an electrical field of 4V/cm in > 95% of ventricular myocardium. Coil configurations examined included a standard parasternal S-ICD coil, dual parallel para-sternal coils, dual coils in series (parasternal and along the left ribcage), and a larger flattened parasternal coil. The standard parasternal S-ICD coil configuration (with < 1mm intervening fat under the coil and generator) resulted in an estimated DFT of 33J. The other coil configurations resulted in marked reductions in DFT by as much as 37% (to 21J) (figure), predominantly related to lower shock impedance and improved electrical field distribution. Our modeling work suggests that modifications to the S-ICD coil design could lead to marked reductions in DFT. This could allow for the creation of S-ICDs with lower energy requirements and correspondingly smaller generators compared to current devices and might obviate the need for VF conversion testing with S-ICDs.

CD3+ lymphocytes predominate in the dermis, epidermis, and adnexal epithelia of the normal dorsolateral thorax of horses

CD3+ lymphocytes predominate in the dermis, epidermis, and adnexal epithelia of the normal dorsolateral thorax of horses

Mortality and Reinfection Rates of the Patients with Mild COVID-19 at the Sixth Month after the Infection

Introduction: The management of the patients with COVID-19 is depend on the clinical presentation. We aimed to evaluate the hospitalization rates due to the progression of the illness in the fist month, the mortality and reinfection rates of the patients with mild COVID-19 during the six months follow-up. Materials and Methods: The study with retrospective design included all SARS CoV-2 PCR positive patients presenting with mild disease to our hospital and who were recommended at-home follow-up during the first month of the COVID-19 pandemic. Demographic characteristics, baseline symptoms, laboratory results and the treatments administered were recorded. The patients were called by phone at six months after the diagnosis. Patients were asked to report hospitalisation at first month, hospitalisation due to any reason and possi- ble reinfections and current symptoms at six month. We noted the mortality rates at first month and at six months from hospital records. Results: The study included 210 patients;130 patients were male. The mean age was 42.3 +/- 15.7 (16-96) years. At baseline, 168 patients (80%) were symptomatic. Fifty-two patients (75.2%) had comorbidities. Thorax computed tomography (CT) was congruent with COVID-19 infection in 46 patients (26%). Twenty-seven patients (16.5%) were hospitalised due to the progression of clinical condition and four (2.4%) needed intensive care transmission. In multivariate analysis, those with comorbidity had having 8.2 fold (95%CI 2.2933.12) D-dimer >= 1 ug/mL had 17.8 fold (OR: 17.8, %95 GA: 3.42-113.3), and diffuse infiltrations in thorax CT scan had 5.36-fold (95% CI 1.46-21.76) higher relative risk for post-COVID hospitalisation. Two (4.1%) out of 48 patients younger than 50 years old and with no risk factors and a normal thorax CT needed hospitalisation. There was no mortality at first month. Four patients (1.9%) died due to deterioration of underlying condition during the six-month follow up. Six patients (3.6%) were considered to be reinfected six months after the first episode. Twenty-six patients (15.6%) had current symptoms which they belived had occured after COVID-19 infection. Conclusion: In the case of the presence of comorbidities, high D-dimer value and diffuse infiltration in thorax CT scan in mild COVID-19 patients, hospitalisation may be the optimal approach.

Correlation of chest CT and RT-PCR testing in coronavirus disease 2019 (COVID-19) in Turkey

Aim: Chest CT plays an important role in the treatment and diagnosis of COVID-19. It is important to remember that patients with RT-PCR test positive for COVID-19 infection may have normal chest CT. Material and Methods: This study included patients who underwent RT-PCR and chest CT tests, as well as patients with suspected and confirmed COVID-19 positive cases according to the algorithm of the Institute of Science of Ministry of Health in Turkey were included in this study. The patients were divided into two groups as positive and negative according to RT-PCR results. These groups were divided into two subgroups: with CT findings compatible with COVID-19 and without them. When the RT-PCR test was taken as the gold standard, the specificity, sensitivity, PPV, NPV, and accuracy rates of chest CT were investigated in detecting COVID-19 infection. Results: RT-PCR was positive in 192 patients and negative in 418 patients. The chest CT scan was positive in 43% (82/192) of 192 patients whose RT-PCR results were positive. Chest CT scan was positive in 25% (108/418) of 418 patients whose RT-PCR results were negative. In 31% of the patients (190/610), chest CT findings were positive for COVID-19. When RT-PCR results were taken as a reference, accuracy, specificity, and sensitivity values in terms of COVID-19 infection of chest CT were 44% (95% CI, 392/610 patients), 43% (95% CI, 82/192 patients), and 74% (95% CI, 310/418 patients) respectively. Discussion: According to these data, we think that chest CT is not very successful in detecting patients infected with COVID-19, contrary to the literature. Clinicians should always be careful to identify patients with COVID-19 infection with normal thorax CT or negative RT-PCR testing.

Automated Identification Model of Ground-Glass Opacity in CT-Scan Image by COVID-19

Ground-Glass Opacity (GGO) is an object found in the thorax due to infection. This object interferes with the normal function of the thorax in breathing. The characteristic of GGO has slightly lighter turbidity compared to normal thorax tissue on radiological images, so it is very difficult to identify it precisely. This study aims to identify the GGO pattern and find the exact area of the CT-scan image of COVID-19 sufferers. The data tested were 34 images from 34 different patients. The image was taken using CT-Scan equipment with the tube model 46274891G1 axially. Each patient is taken one image with the reading position right above the chest using the file format Joint Photographic Experts Group (jpg). An automatic image processing model developed in this study uses several interrelated and continuous technical steps; Image Enhancement, Convert to Binary Image, Morphology Operation, Image Inverted, Active Contour Model, Image Addition, Convert Matrix to Grayscale, Image Filtering, Convert to Binary Image, Image Subtraction and Region Properties. The results of this study can identify GGO in all patient test images, where each patient has GGO. The smallest area of GGO was 3.9%, and the highest was 34.2% of the total thorax area. This level of comparison is greatly influenced by the severity of the COVID-19 virus patient. This area of GGO weakens the normal function of the thorax in the respiratory process of the patient. Thus, this research can be used as a model recommendation in identifying thorax damage due to COVID-19 very well in following up on more intensive treatment in the future.

How does external lateral stabilization constrain normal gait, apart from improving medio-lateral gait stability?

Background: The effect of external lateral stabilization on medio-lateral gait stability has been investigated previously. However, existing lateral stabilization devices not only constrain lateral motions but also transverse and frontal pelvis rotations. This study aimed to investigate the effect of external lateral stabilization with and without constrained transverse pelvis rotation on mechanical and metabolic gait features. Methods: We undertook two experiments with 11 and 10 young adult subjects, respectively. Kinematic, kinetic and breath-by-breath oxygen consumption data were recorded during three walking conditions (normal walking (Normal), lateral stabilization with (Free) and without transverse pelvis rotation (Restricted)) and at three speeds (0.83, 1.25 and 1.66 m s−1) for each condition. In the second experiment, we reduced the weight of the frame, and allowed for longer habituation time to the stabilized conditions. Results: External lateral stabilization significantly reduced the amplitudes of the transverse and frontal pelvis rotations, in addition to medio-lateral, anterior–posterior, and vertical pelvis displacements, transverse thorax rotation, arm swing, step length and step width. The amplitudes of free vertical moment, anterior–posterior drift over a trial, and energy cost were not significantly influenced by external lateral stabilization. The removal of pelvic rotation restrictions by our experimental set-ups resulted in normal frontal pelvis rotation in Experiment 1 and significantly higher transverse pelvis rotation in Experiment 2, although transverse pelvis rotation still remained significantly less than in the Normal condition. Step length increased with the increased transverse pelvis rotation. Conclusion: Existing lateral stabilization set-ups not only constrain medio-lateral motions (i.e. medio-lateral pelvis displacement) but also constrain other movements such as transverse and frontal pelvis rotations, which leads to several other gait changes such as reduced transverse thorax rotation, and arm swing. Our new set-ups allowed for normal frontal pelvis rotation and more transverse pelvis rotation (yet less than normal). However, this did not result in more normal thorax rotation and arm swing. Hence, to provide medio-lateral support without constraining other gait variables, more elaborate set-ups are needed.

Classification of Thorax X-ray Results on Corona Virus Infection Based on Internet of Things (IoT)

The spread of the corona virus in Indonesia is still growing until now. One important thing to note is about the handling of patients exposed to the coronavirus. This study aims to be able to classify thorax x-ray images against corona virus infection based on the Internet of Things (IoT). IoT is a concept of internet connectivity that is connected continuously between remote devices. This study uses a supervised learning method, namely directed learning in which the expected results of the user have been trained in advance and the information is stored in the system (database). The training data used is a Thorax x-ray image that is processed based on image processing with segmentation and edge detection based on the Sobel operator with real time connected to the internet. The results showed that the 100 times experiment obtained the accuracy value of the normal Thorax X-ray image of 94% and the Thorax covid-19 X-ray image of 96%. Overall system test showed 95% on target and 5% error.

Evaluation of radiological findings in pediatric patients with COVID-19 in Turkey.

OBJECTIVE:The objective of the study was to describe the findings of pediatric patients diagnosed with COVID-19 in computed tomography (CT) and chest X-ray (CXR) images. Therefore, the aim of this study is to show protecting the children from radiation as much as possible while guiding the diagnosis.METHODS:Between March and June 2020, 148 pediatric patients examined who underwent CT due to suspicion of COVID-19. Fifty patients of 148 with normal thorax CT and negative reverse transcription polymerase chain reaction (RT-PCR) were excluded from the study. Of the remaining 98 patients were evaluated retrospectively by two pediatric radiologists with 15 years of experience.RESULTS:The demographic, clinical, and laboratory data were evaluated for 52 RT-PCR-positive patients. CT finding of 23 RT-PCR positive and 12 negative patients was classified. According to our study, unilateral (61–67%), multifocal (50–52%), and peripheral (83–91%) involvement were higher in all groups. Lower lobe involvement was frequently detected (58–65%). The most frequently detected parenchymal lesion was ground-glass opacity followed by consolidated areas accompanying ground-grass opacities. Halo sign and vascular enlargement signs were the common signs of lung lesions (35%). In addition, some rare findings not previously described in this disease in children were mentioned in this study. The clinical course of all our patients was mild and control radiological imaging checked by CXR.CONCLUSION:Most pediatric patients have a mild course. Hence, a balance between the risk of radiation and necessity for chest CT is very important. Low-dose CT scan is more suitable for pediatric patients but still it should be used cautiously.

Anatomical Assessment of the Thorax in the Neonatal Foal Using Computed Tomography Angiography, Sectional Anatomy, and Gross Dissections.

The purpose of this study was to correlate the anatomic features of the normal thorax of neonatal foals identified by CTA, with anatomical sections and gross dissections. Contrast-enhanced transverse CTA images were obtained in three neonatal foals using a helical CT scanner. All sections were imaged with a bone, mediastinal, and lung windows setting. Moreover, cardiac volume-rendered reconstructed images were obtained. After CT imaging, the cadaver foals were sectioned and dissected to facilitate the interpretation of the intrathoracic cardiovascular structures to the corresponding CTA images. Anatomic details of the thorax of neonatal foals were identified according to the characteristics of CT density of the different organic tissues and compared with the corresponding anatomical sections and gross dissections. The information obtained provided a valid anatomic pattern of the thorax of foals, and useful information for CTA studies of this region.

The costochondral length in patients with pectus excavatum is longer than that of the normal thorax.

Recently, several investigators reported that costal cartilage does not overgrow in pectus excavatum (PE). We wished to clarify whether costochondral length is longer in PE than the normal thorax and we tried to clarify the change of the shape of precordial concavity according to the growth in PE. We evaluated 243 CT axial images of patients with PE and 246 CT axial images of patients without thoracic deformity. We divided the fifth costal cartilage into several lengths. We considered each part to be a straight line and calculated the length of the lines. We compared the approximate costochondral length between PE and normal thorax. We analyzed the distance between both anterior tips of fifth rib, and the ratio of the width and the depth of concavity to thoracic diameter in PE. The costochondral length in patients with PE is highly likely to be longer than that of the normal thorax. The length of costal cartilage may be longer in asymmetric PE than symmetric PE. It may start in infantile period in PE that the thoracic shape turns into asymmetry from symmetry. The precordial concavity of PE may be shaped by overgrowth of both costal cartilages and ribs.

Comparison of Grayscale and Histogram Thorax Computed Radiography (CR) Image in Tuberculosis (TBC) Patients with Normal Thorax Image

Comparison of Grayscale and Histogram Thorax Computed Radiography (CR) Image in Tuberculosis (TBC) Patients with Normal Thorax Image

The measurement of the normal thorax using the Haller index methodology at multiple vertebral levels.

The Haller index is a ratio of thoracic width and height, measured from an axial CT image and used to describe the internal dimensions of the thoracic cage. Although the Haller index for a normal thorax has been established (Haller etal. 1987; Daunt etal. 2004), this is only at one undefined vertebral level in the thorax. What is not clear is how the Haller index describes the thorax at every vertebral level in the absence of sternal deformity, or how this is affected by age. This paper documents the shape of the thorax using the Haller index calculated from the thoracic width and height at all vertebral levels of the thorax between 8 and 18years of age. The Haller Index changes with vertebral level, with the largest ratio seen in the most cranial levels of the thorax. Increasing age alters the shape of the thorax, with the most cranial vertebral levels having a greater Haller index over the mid thorax, which does not change. A slight increase is seen in the more caudal vertebral levels. These data highlight that a 'one size fits all' rule for chest width and depth ratio at all ages and all thoracic levels is not appropriate. The normal range for width to height ratio should be based on a patient's age and vertebral level.

New-Onset Sarcoidosis After Remission of Cushing's Syndrome.

Exposure to high levels of endogenous or exogenous glucocorticoids suppresses the inflammatory response genes. Excessive endogenous hypercortisolism may mask the active inflammatory diseases. Rebound immune modulation may occur after Cushing's syndrome (CS) remission, leading to the new onset of autoimmune diseases. Here, we report a 27-year-old female patient who was recently diagnosed with sarcoidosis after remission of CS. Normal thorax imaging showed that the patient was free of disease during the course of CS and without any symptoms of sarcoidosis. After complete remission of CS, she was diagnosed with sarcoidosis based on clinical and radiological evidence. Excessive hypercortisolism may suppress the active inflammatory stage of sarcoidosis. However, the disease became apparent after the reduction of cortisol levels following the treatment of CS.

Thoax CT Scan as Invasive Fungal Infection (IFI) Screening In Neutropenic Patients, a Prospective-Retrospective Experience of It Impact on Therapeutic Intervention.

AbstractAbstract 4554 Introduction:Persistent fever in high risk neutropenic patients (HRNF) after day 5 of empiric treatment is a sign of high susceptibility for IFI with elevated morbidity and mortality. Diagnostic tools in this setting are inaccurate to determine the occurrence of IFI and most patients start with empiric antifungal agents. Drugs are usually associated with increasing costs and toxicity. It is challenging to establish the population of patients in whom in spite of persistent fever and neutropenia, avoidance of antifungal treatment is a reasonable strategy. Methods:We have prospectively allocated 229 HRNF patients in different empiric antimicrobial regimens over a 4.5 year period. In a retrospective revision, there were 33 patients with persistent fever on day 5 of empirical antimicrobial treatment and no evident new infection episode or clinical impairment. In 28 patients, a thorax CT scan was performed as part of the evaluation of persistent fever. The clinical outcome was evaluated regarding the presence or absence of pulmonary infiltrates in the CT scans. Initial empiric antifungal treatment, transfusions, days in hospital, days with neutropenia, antimicrobial treatment, and days with fever were evaluated. Results:Nineteen patients (68%) of 28 presented with pulmonary infiltrates. All of them received antifungal treatment. In 9 patients with normal CT scan antifungal treatment was deferred. The difference of the decision in not giving antifungals according CT scans was highly significant (p <0,0001). Transfusions of red blood cells and platelets were significantly less in the group of normal scans (p 0,0004 and 0,005 respectively). Antimicrobial treatment, days in hospital and days with fever were not significantly different in both groups. There was one death in the normal scan group due to relapse. Mortality was not significantly different in both groups. Conclusion:In HRNP, normal thorax CT scan changed the clinical decision in not starting antifungal treatment in spite of persistent fever. There was no difference in mortality with patients under antifungal treatment, allowing continuing with this strategy in more patients in the future. Disclosures:No relevant conflicts of interest to declare.

Three-dimensional MRA Study of the Normal Canine Thorax: MIP Sections and Volume Rendering

The purpose of this study was to investigate the feasibility of three-dimensional contrast-enhanced magnetic resonance angiography (3D-CE-MRA) for the non-invasive anatomical evaluation of the thoracic vasculature in five normal Beagles. After intravenous gadolinium administration and a cardio-respiratory gating protocol, fast 3D gradient echo pulse sequence MRA was performed employing a 1.5 Tesla magnet and a human thorax coil. Three-dimensional vascular software was applied. Sagittal, transverse and dorsal maximum intensity projection (MIP) sections and volume rendering (VR) images were obtained and labelled. Anatomical literature, dissections and gross sections were employed to assist the identification of the vascular structures. With improvements in scanner technology, MIP sections and VR images are a promising, non-invasive and accurate method of evaluating the canine thoracic vasculature. Images provide a reference material for clinical studies of the canine thorax for radiologist-surgeon teamwork assessment and also encourage the development of this technique in veterinary medicine.

P0634 ABDOMINAL TUBERCULOSIS WITHOUT PULMONARY INVOLVEMENT: DIFFERENTIAL DIAGNOSTIC WITH CROHN???S DISEASE

Introduction: Tuberculosis is a relatively common disease in developing countries. Abdominal tuberculosis(AT)is a rare location of this infectious disease with diagnostic difficulties until today. In most, disease is confined to the terminal ileum and cecum. We report one case of colonic commitment, similar to Crohn’s disease. Methods: Restrospective study of clinical records Results: A ten-year-old boy, with diary abdominal pain, low-grade fever, weight loss and mucopurulent chronic diarrhea for the last 4 months was admitted at the gastropediatric unit of Hospital Municipal Jesus. The severity of symptoms majored with bloody diarrhea and severe pain. No previous pathological history was found. BCG scar was present, PPD reaction and anti- HIV were negative, normal thorax scan, ESR = 90 mm, hemoglobin= 9,7g/dl, hematocrite= 30,5% abdominal ultrasound (US) with evidences of thickening of mesentery and colonic wall (distal transverse colon and proximal left colon), narrowing of intestinal lumen, similar to inflammatory bowel disease. Sulfasalazine was the initial therapy on Day(D) 2 of evolution, associated to metilprednisolone on D10. Fever, pain and diarrhea decreased after D11. On D28, abdominal US demonstrated reduction of mural thickness of the colon and colonoscopy with thickening of splenic flexure, nodularity of mucosal surface with some ulceration similar to Crohn’s disease. Metilprednisolone was switched to prednisona. On D43, barium enema had evidencieted luminal narrowing of splenic flexure. Clinical improvement was achieved but on D44, the colonic biopsy was compatible with granulomatous inflammatory process with innumerous BAAR (Ziel-Nielsen positive). The corticotherapy was then progressive suspended and The RIP schema was began (usual doses). He went home on D56 without symptoms. After 3 months of RIP treatment, an intestinal suboclusion leads to colectomy of distal transverse and proximal left colon with evidences of fistulas. Tuberculosis was confirmed byhistopathological study of the specimen. Conclusion: The therapy was suspended with success after 9 months. The patient remains well until now. The diagnosis of AT was misdiagnosed because the absence of laboratorial evidence of the infection and clinical improvement after Crohn’s disease therapy.

O controle da tuberculose entre os índios Yanomami do Alto Rio Negro

Summary Due to the high incidence of the tuberculosis registered on year 2000 (all forms of tuber culosis = 1.61 1,3 for 100.000 inhabitants; pulmonary positives = 402,8 for 100.000 inhabitants) at the aboriginal villages MaturacAE, Ariabu and Auxiliadora of the Yanomami people, in the Amazon region of the high Black River in the State of Amazon, in April of 2002, efforts aiming the control of tuberculosis those indians,. The action consisted of an active search of tuberculosis cases in the villages through the examination (X-ray, PPD and baciloscopia) of those with respiratory symptoms and the contacts of cases of pulmonar y tuber culosis with positive smear notified during the last 2 years. Installing a por table X-ray equipment in the proper village resulted in gr eat utility, allowing 75 examinations in few days Beyond 2 positive pulmonary cases already known by the local system of health in the year of 2002, more 13 cases of tuber culosis (2 pulmonar y positives, 9 pulmonar y without bacteriological confirmation and 1 extra-pulmonar y) wer e discover ed. The patients were tr eated and the contacts of the positive cases without symptoms or suggestive signals of tuber culosis, strong reactors to the test with PPD, x-ray of normal thorax, the underwent chemoprophilaxis using isoniazida. After 11 months, in March of 2003, no new case had been registered and the repetition of the test with the PPD did not detect reaction in childr en of 15 years old or less.

The characteristics of thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis.

1. Thoracic insufficiency syndrome is the inability of the thorax to support normal respiration or lung growth. 2. The rare condition of fused ribs and congenital scoliosis may result in a three-dimensional thoracic deformity with adverse effects on thoracic growth and function with development of thoracic insufficiency syndrome. 3. The normal thorax is defined by two characteristics: normal, stable volume and the ability to change that volume. Volume depends on the width and depth of the rib cage, and the thoracic spine provides height. The ability to change volume, termed thoracic function, is provided by the diaphragm and the secondary muscles of respiration. 4. On radiographs, the loss of the vertical height of the lung of the concave, restricted hemithorax is defined by the percentage of space available for the lung. 5. Spine rotation causes a windswept thorax, with both restriction of the volume of the convex hemithorax and restriction of the motion of the involved ribs. 6. Constrictive three-dimensional deformity of the thorax may cause extrinsic, restrictive lung disease. 7. Progressive thoracic insufficiency syndrome is diagnosed on the basis of clinical signs of respiratory insufficiency, loss of chest wall mobility as demonstrated by the thumb excursion test, worsening indices of three-dimensional thoracic deformity on radiographs and computed tomography scans, or a relative decline in percent predicted vital capacity due to thoracic "failure to thrive," as demonstrated by pulmonary function tests. 8. Treatment of progressive thoracic insufficiency syndrome should provide an acute increase in the thoracic volume with stabilization of any flail chest-wall defects and maintain these improvements as the patient grows, without the need for spine fusion.