Three-dimensional imaging of the pediatric trachea in congenital tracheal stenosis

Non-operative management of congenital tracheal stenosis: criteria by computed tomography

OBJECTIVES

Whether to perform surgical or conservative treatment for congenital tracheal stenosis (CTS) is controversial. Thus, the computed tomography (CT) criteria for conservative treatment of CTS were investigated.

METHODS

From 2005 to 2017, 28 CTS cases were included. The operative cases and preoperative death cases constituted the required intervention group (group I), and the non-operative surviving cases constituted the observation group (group O). The diameter of the tracheal narrowest part (DTNP) on CT was evaluated as a criterion for non-operative follow-up.

RESULTS

Chest CT was performed 19 times in 19 group I cases and 18 times in 9 group O cases. The median age of the patients that underwent CT scan examinations was 3.4 months (range 0-25 months) in group I and 22 months (range 0-60 months) in group O. The cut-off values of the non-operative criteria were 40.8% (AUC: 0.82, p < .01) normal for age of the trachea's narrowest part, and 41.6% normal for body weight (AUC: 0.92, p < .01), respectively.

CONCLUSIONS

DTNP is 40% and more of the normal diameter appears necessary for non-surgical management. The present study suggests that the criteria for conservative management of CTS are that the DTNP is not less than 40% of the normal tracheal diameter, with a few symptoms.

Role of multi-slice and three-dimensional computed tomography in delineating extracardiac vascular abnormalities in neonates

BACKGROUND

Recent advances in multi-slice computed tomography (MSCT) and three-dimensional computed tomography (3D CT) provide good-resolution images and short scan time for complete diagnosis of congenital heart disease (CHD). In the present study, we found that MSCT rapidly provides clinically relevant information for diagnosing extracardiac vascular anatomy in neonates with CHD. It is less invasive, necessitating only minimum or no sedation and a relatively small amount of contrast material. These advantages are crucial, especially for critically ill neonates.

METHODS

Between January 2007 and December 2008, MSCT scans were conducted on 41 neonates who were admitted to our neonatal intensive care unit. All the neonates were suspected to have complex CHD after an initial echocardiography examination. The scans were focused on detecting extracardiac vascular anatomy and abnormalities. All the image data sets were sent to image processing workstations for multiplanar interactive viewing and 3D reconstruction.

RESULTS

High-resolution MSCT scan images were obtained from 41 patients. Reported indications and findings of extracardiac abnormalities and related structural anatomy pertaining to congenital heart disease from MSCT and 3D CT findings were confirmed by clinical and surgical findings by a team of multidisciplinary congenital heart disease specialists.

CONCLUSION

Based on clinical and surgical confirmation of the MSCT scan results from a multidisciplinary congenital heart disease specialist team, we concluded that adequate information on CHD, specifically that regarding extracardiac abnormalities of the anatomy, can be obtained and MSCT can be used to replace cardiac catheterization.

CT demonstration of "chicken trachea" resulting from complete cartilaginous rings of the trachea in ring-sling complex

We report a 10-month-old infant who presented with tetralogy of Fallot and respiratory disease in whom the suspicion of a ring-sling complex was confirmed by high-resolution CT. CT demonstrated the typical association of left pulmonary artery sling and the "chicken trachea" resulting from complete cartilaginous rings of the trachea.

[Volume CT: recent advances in acquired abnormalities of the trachea]

OBJECTIVES

To show the recent improvements in CT imaging of the trachea due to the introduction of multidetector computed tomography (MDCT).

MATERIAL AND METHODS

MDCT technology, which was introduced in the early 00's, allows acquiring the entire airways within few seconds while using low dose parameters thanks to the natural high contrast of the airways.

RESULTS

Volume acquisition with isotropic voxels offers an excellent anatomical resolution in all directions, improving the quality of multiplanar reformations and 3D reconstructions, including virtual bronchoscopy. Therefore, the ability of CT for detecting and localizing tracheal abnormalities are improved, which is useful for planning endoscopy or open surgery, or assess their results. Dynamic acquisition during expiration is the last refinement permitted by MDCT, which is of value to detect tracheomalacia.

CONCLUSIONS

MDCT is a non-invasive technique to image the trachea. Its applications are numerous, such as depiction of anatomical or functional abnormalities, evaluation of local extent of the disease, planning and assessing open surgery or interventional endoscopy.

The role of conservative management in congenital tracheal stenosis: an evidence-based long-term follow-up study

BACKGROUND/PURPOSE

Surgery has been the management of choice for severe congenital tracheal stenosis (CTS). The role of conservative management of CTS however is not clear. The aim of this study is to characterize the natural history of CTS, review the radiologic evidence of tracheal growth, and evaluate the clinical outcome and selection criteria of conservative management of CTS.

METHODS

A retrospective study was carried out on 22 consecutive children with symptomatic CTS admitted into a single institution between 1982 and 2001. The patients were categorized into operation (n = 11) and observation (n = 11) groups. Six patients of the observation group were followed up with serial computed tomography scan. Their tracheal growth was compared with that of healthy children of the same age.

RESULTS

The mortality rates of observation and operation groups were 9% and 27%, respectively, although the latter group consisted of more severely affected patients. The pathologic categorization of the CTS influenced the survival rates (P = .046, chi2), with the long segment type having the worst prognosis (67%). Serial computed tomography scans of 6 conservatively managed patients revealed that all stenotic tracheas continued to grow (P = .039, 2-tailed paired Student's t test). Of the 6 stenotic tracheas, 5 grew at a faster-than-normal rate, and the stenotic tracheal diameters approached those of normal diameters by the age of 9 years.

CONCLUSIONS

The management of patients with symptomatic CTS should be individualized. A selected group of patients with CTS can be safely managed nonoperatively.

Evaluation of obstructive airway lesions in complex congenital heart disease using composite volume-rendered images from multislice CT

BACKGROUND

Multislice CT (MSCT) allows high-quality volume-rendered (VR) and composite volume-rendered images.

OBJECTIVE

To investigate the clinical usefulness of composite VR images in the evaluation of the relationship between cardiovascular structures and the airway in children with complex congenital heart disease (CHD).

MATERIALS AND METHODS

Four- or 16-slice MSCT scanning was performed consecutively in 77 children (mean age 6.4 months) with CHD and respiratory symptoms, a chest radiographic abnormality, or abnormal course of the pulmonary artery on ECHO. MSCT scanning was performed during breathing or after sedation. Contrast medium (2 ml/kg) was administered through a pedal venous route or arm vein in all patients. The VR technique was used to reconstruct the cardiovascular structures and airway, and then both VR images were composed using the commercial software (VoxelPlus(2); Daejeon, Korea).

RESULTS

Stenoses were seen in the trachea in 1 patient and in the bronchi in 14 patients (19%). Other patients with complex CHD did not have significant airway stenoses.

CONCLUSIONS

Composite VR images with MSCT can provide more exact airway images in relationship to the surrounding cardiovascular structures and thus help in optimizing management strategies in treating CHD.

Computed tomography versus bronchography in the diagnosis and management of tracheobronchomalacia in ventilator dependent infants

AIM

To assess the relative accuracy of dynamic spiral computed tomography (CT) compared with tracheobronchography, in a population of ventilator dependent infants with suspected tracheobroncho-malacia (TBM).

SETTING

Paediatric intensive care unit in a tertiary teaching hospital.

PATIENTS AND METHODS

Infants referred for investigation and management of ventilator dependence and suspected of having TBM were recruited into the study. Tracheobronchography and CT were performed during the same admission by different investigators who were blinded to the results of the other investigation. The study was approved by the hospital research ethics committee, and signed parental consent was obtained.

RESULTS

Sixteen infants were recruited into the study. Fifteen had been born prematurely, and five had cardiovascular malformations. In 10 patients there was good or partial correlation between the two investigations, but in six patients there was poor or no correlation. Bronchography consistently showed more dynamic abnormalities, although CT picked up an unsuspected double aortic arch. Radiation doses were 0.27-2.47 mSv with bronchography and 0.86-10.67 mSv with CT.

CONCLUSIONS

Bronchography was a better investigation for diagnosing TBM and in determining opening pressures. Spiral CT is unreliable in the assessment of TBM in ventilator dependent infants. In addition, radiation doses were considerably higher with CT.

Surgical Treatment of Pulmonary Artery Sling and Tracheal Stenosis

BACKGROUND

Pulmonary artery sling is a rare vascular ring and is commonly associated with tracheal stenosis. Symptomatic newborns and infants with these complex lesions have a high mortality rate without surgical intervention. The ideal operation remains controversial, with debate focusing on the need for left pulmonary artery for reimplantation and the technique of tracheal reconstruction.

METHODS

From 1983 to 2003, 14 patients with pulmonary artery sling (mean age, 7 months; range, 6 days to 27 months) underwent repair of pulmonary artery sling alone (6 patients), tracheoplasty alone (1 patient), and pulmonary artery sling repair with tracheoplasty (7 patients). Preoperatively, 7 patients were intubated, 2 had VATER (vertebral, anal, tracheal, esophageal, and radial anomalies) syndrome, and 2 patients had agenesis of the right lung. The left pulmonary artery was reimplanted at the ductal insertion site in 13 patients. One patient had left pulmonary artery translocation. Tracheoplasty employing extracorporeal circulation consisted of autologous pericardial patch (6 patients) or slide tracheoplasty (2 patients). Six patients with pulmonary artery sling and mild tracheal stenosis required only left pulmonary artery reimplantation. Concomitant procedures included closure of atrial septal defect (4 patients), ventricular septal defect (4 patients), and shunt for Fallot's tetralogy (2 patients).

RESULTS

There were 2 hospital deaths (2 of 14;14%) from abdominal sepsis (1) and renal failure (1). Reoperations included diaphragm plication (2), tracheostomy (1), and bronchoscopy with laser resection of granulation tissue (5 patients: 2 slide, 3 pericardium). Follow-up was complete in all patients (mean, 42 months) with 1 late death from fungal sepsis. At follow-up, all left pulmonary artery anastomoses were patent by echocardiography, and no patient has required reoperation for trachea reconstruction.

CONCLUSIONS

These data demonstrate that tracheal repair is not always necessary in the presence of pulmonary artery sling; that agenesis of the right lung is not a contraindication to successful complete repair; and that simultaneous correction of intracardiac defects can be safely performed in selected patients. This study suggests that in newborns and infants, pericardial patch and slide tracheoplasty are effective methods for trachea reconstruction.

The management of congenital tracheal stenosis

This paper reviews current concepts and results in the management of congenital tracheal stenosis (CTS). Diagnostic options are considered and the requirements for successful management defined. Chief amongst these is a multi-disciplinary approach with individualised patient management. Severe long-segment CTS represents the biggest challenge to clinicians and the worst problems for affected families. Near-death episodes are frequent in affected infants and some cannot be ventilated and require ECMO. Associated cardiovascular anomalies are frequent. Patients require immediate resuscitation and transfer to a specialist unit. After careful assessment, accurate diagnosis and discussion, primary resection and end-to-end repair with a slide technique should always be the first option, with concomitant repair of associated cardiac anomalies. If this is impossible because of the severity of the lesion, some form of patch tracheoplasty will be indicated. Cardiopulmonary bypass is often required. Patches include pericardium, autograft trachea, carotid artery, cartilage, and allograft trachea. Mortality ranges from 0 to 30% in the literature, which largely comprises single-centre long-term experience. Recurrence is common and can be managed by stenting and tracheal homograft implantation. Long-term quality of life of survivors is little reported but seems good. Physiological data are lacking. To improve results, we suggest a treatment algorithm to rationalise care.

Tracheobronchography and angiocardiography of paediatric cardiac patients with airway disorders

OBJECTIVE

We report our experience in combining tracheobronchography and angiocardiography in the assessment of a selected cohort of paediatric cardiac patients with problematic airway disorders.

METHODOLOGY

The clinical records of 11 patients who underwent 17 studies at a median age of 5.5 months (range 3 months to 10.8 years) were reviewed. Tracheobronchography and angiocardiography were performed under general anaesthesia using a non-ionic contrast agent. The findings were compared with those of flexible bronchoscopy and magnetic resonance imaging (MRI).

RESULTS

Seven patients had cardiac lesions associated with vascular anomalies potentially compressing the airway, while four had no identifiable aberrant or enlarged vessels. All examinations but one were performed without complications. Tracheobronchography demonstrated extrinsic vascular compression with secondary airway malacia in three (27%), intrinsic tracheobronchial stenosis in five (45%), and airway malacia in three patients (27%). Precise measurement of the airway calibre and real-time fluoroscopic monitoring facilitated transcatheter tracheobronchial interventions (six balloon dilations, three stent implantations) in four patients. In conjunction with angiocardiography, cine-tracheobronchography provided detailed information on the spatial relationship between vascular and airway structures in all patients; allowed dynamic assessment of airway malacia; and facilitated preoperative planning in six patients. In contrast, bronchoscopy failed to differentiate malacia from extrinsic compression in four patients (36%), while MRI, performed in six patients, was unsatisfactory in one due to a motion artefact and failed to diagnose airway malacia and extrinsic compression in three patients.

CONCLUSIONS

Tracheobronchography is relatively safe in paediatric cardiac patients. Combined tracheobronchography and angiocardiography, a less operator-dependent imaging modality compared to bronchoscopy and MRI, delineated the airway and vascular anatomy in detail; facilitated preoperative planning; and permitted transcatheter tracheo-bronchial interventions. The dynamic capability of tracheobronchography supplements that of flexible bronchoscopy and MRI in the diagnosis of airway malacia.

Clinical applications of 2D and 3D CT imaging of the airways--a review

Hardware and software evolution has broadened the possibilities of 2D and 3D reformatting of spiral CT and MR data set. In the study of the thorax, intrinsic benefits of volumetric CT scanning and better quality of reconstructed images offer us the possibility to apply additional rendering techniques to everyday clinical practice. Considering the large number and redundancy of possible post-processing imaging techniques that we can apply to raw CT sections data, it is necessary to precisely set a well-defined number of clinical applications of each of them, by careful evaluation of their benefits and possible pitfalls in each clinical setting. In diagnostic evaluation of pathological processes affecting the airways, a huge number of thin sections is necessary for detailed appraisal and has to be evaluated, and information must then be transferred to referring clinicians. By additional rendering it is possible to make image evaluation and data transfer easier, faster, and more effective. In the study of central airways, additional rendering can be of interest for precise evaluation of the length, morphology, and degree of stenoses. It may help in depicting exactly the locoregional extent of central tumours by better display of relations with bronchovascular interfaces and can increase CT/bronchoscopy sinergy. It may allow closer radiotherapy planning and better depiction of air collections, and, finally, it could ease panoramic evaluation of the results of dynamic or functional studies, that are made possible by increased speed of spiral scanning. When applied to the evaluation of peripheral airways, as a completion to conventional HRCT scans, High-Resolution Volumetric CT, by projection slabs applied to target areas of interest, can better depict the profusion and extension of affected bronchial segments in bronchiectasis, influence the choice of different approaches for tissue sampling by better evaluation of the relations of lung nodules with the airways, or help to detect otherwise overlooked slight pathological findings. In the exploration of the air-spaces of the head and neck, targeted multiplanar study can now be performed without additional scanning by retro-reconstructed sections from original transverse CT slices. Additional rendering can help in surgical planning, by simulation of surgical approaches, and allows better integration with functional paranasal sinuses endoscopic surgery, by endoscopic perspective rendering. Whichever application we perform, the clinical value of 2D and 3D rendering techniques lies in the possibility of overcoming perceptual difficulties and 'slice pollution', by easing more efficient data transfer without loss of information. 3D imaging should not be considered, in the large majority of cases, as a diagnostic tool: looking at reformatted images may increase diagnostic accuracy in only very few cases, but an increase in diagnostic confidence could be not negligible. The purpose of the radiologist skilled in post-processing techniques should be that of modifying patient management, by more confident diagnostic evaluation, in a small number of patients, and, in a larger number of cases, by simplifying communication with referring physicians and surgeons. We will display in detail possible clinical applications of the different 2D and 3D imaging techniques, in the study of the tracheobronchial tree, larynx, nasal cavities and paranasal sinuses by Helical CT, review relating bibliography, and briefly discuss pitfalls and perspectives of CT rendering techniques for each field.

Slide tracheoplasty in the management of congenital tracheal stenosis

Long-segment congenital tracheal stenosis (LSCTS) is a rare condition. Originally, it was felt to be uniformly fatal; however, advances in technique have made surgical repair and survival possible. Our objective is to report results and technique of slide tracheoplasty for the treatment of LSCTS in the context of the overall experience at the Children's Memorial Hospital in Chicago. We reviewed 37 cases of infants and children with LSCTS. Thirty of the 37 infants underwent surgical intervention. Slide tracheoplasty resulted in survival in 1 of 2 infants, and pericardial patch tracheoplasty resulted in survival in 21 of 28 (75%). Of the 30 patients who had surgical repair, 7 (23%) have died, and 1 has been lost to follow-up (3%). Follow-up has ranged from 6 months to 13 years. Slide tracheoplasty is a satisfactory adjunct to existing techniques. With early diagnosis and appropriate management of LSCTS, survival is possible in a majority of patients.

Three-dimensional imaging of the pediatric airway

Accurate imaging of the pediatric tracheobronchial tree is indicated for the evaluation of congenital or acquired abnormalities. Conventional axial computed tomography (CT) is now considered the best imaging modality for evaluation of the trachea and major bronchi, and has almost completely replaced the former gold standard of tracheobronchography. Preliminary results indicate that CT scan performance is further enhanced through the application of spiral technology and two-dimensional (2D) and 3D representation of the tracheobronchial tree. Spiral CT scans with 3D surface rendering offers an opportunity to replace traditional tracheobronchography with a safer, less invasive modality.

Spiral computed tomography with 3-dimensional reconstruction for the diagnosis of tracheobronchial stenosis

We report on the usefulness of spiral computed tomography (CT) with 3-dimensional (3D) reconstruction in the diagnosis of tracheobronchial abnormalities based on three cases of children with congenital tracheobronchial strictures. Images were reconstructed using a curved planar reformat and shaded surface display. The images obtained from our three cases of tracheal stenosis, subglottic stenosis and tracheobronchial strictures were extremely clear. Spiral CT with 3D reconstruction provides excellent anatomic delineation of the tracheobronchial airway, and is safe and less invasive than tracheobronchography.

3D virtual endoscopy of the upper airway: optimization of the scan parameters in a cadaver phantom and clinical assessment

Our goal was to evaluate the influence of the scan parameters on the 3D virtual endoscopy of the larynx and trachea and the clinical assessment. Helical CT (HiSpeed Advantage; GE, Milwaukee, WI, U.S.A.) of a cadaver phantom was performed with increased collimation (1-10 mm) and pitch (0.5-3). Seventy-two patients with complaints of the upper airways were investigated by virtual endoscopy and their results were compared with the findings of regular endoscopy. Best correlation between virtual endoscopy and anatomical findings, diagnostic quality of the axial slices, and useful longitudinal coverage of the examination were obtained with a collimation of 3 mm and a pitch of 1.5. Space-occupying tumors and stenosis were detected correctly, but the mucous membrane could not be visualized. 3D virtual endoscopy proved to be a valuable method for displaying anatomical structures. For an optimal protocol, a collimation of 3 mm with a pitch of 1.5 is recommended.

Spiral computed tomographic scanning of the chest with three dimensional imaging in the diagnosis and management of paediatric intrathoracic airway obstruction

BACKGROUND

The usefulness of spiral computed tomographic (CT) scans of the chest with three dimensional imaging (3D-CT) of intrathoracic structures in the diagnosis and management of paediatric intrathoracic airway obstruction was assessed.

METHODS

A retrospective review was made of five consecutive cases (age range six months to four years) admitted to the paediatric intensive care unit and paediatric radiology division of a tertiary care children's hospital with severe respiratory decompensation suspected of being caused by intrathoracic large airway obstruction. Under adequate sedation, the patients underwent high speed spiral CT scanning of the thorax. Non-ionic contrast solution was injected in two patients to demonstrate the anatomical relationship between the airway and the intrathoracic large vessels. Using computer software, three-dimensional images of intrathoracic structures were then reconstructed by the radiologist.

RESULTS

In all five patients the imaging results were useful in directing the physician to the correct diagnosis and appropriate management. In one patient, who had undergone repair of tetralogy of Fallot with absent pulmonary valve, the 3D-CT image showed bilateral disruptions in the integrity of the tracheobronchial tree due to compression by a dilated pulmonary artery. This patient underwent pulmonary artery aneurysmorrhaphy and required continued home mechanical ventilation via tracheostomy. In three other patients with symptoms of lower airway obstruction the 3D-CT images showed significant stenosis in segments of the tracheobronchial tree in two of them, and subsequent bronchoscopy established a diagnosis of segmental bronchomalacia. These two patients required mechanical ventilation and distending pressure to relieve their bronchospasm. In another patient who had undergone surgical repair of intrathoracic tracheal stenosis three years prior to admission the 3D-CT scan ruled out restenosis as the reason for her acute respiratory decompensation.

CONCLUSIONS

3D-CT scanning is a useful additional diagnostic tool for intrathoracic airway obstruction in paediatric patients.

Tracheobronchography in children

Tracheobronchography (TBG) can provide anatomic information supplementing endoscopy in evaluating complex congenital and acquired tracheal abnormalities. With the use of modern non-ionic contrast agents and flexible fiberoptic bronchoscopes, TBG can be performed safely and comfortably in children. As some tracheal lesions have a significant risk of mortality, obtaining maximum definition of the abnormality is imperative prior to attempting surgical management. Twenty-two patients underwent TBG at St. Christopher's Hospital for Children (Philadelphia) from July 1990 through June 1995. With the use of iohexol as a contrast agent, flexible bronchoscopes and adequate sedation and analgesia, without the need for intubation or general anesthesia, there were no significant complications or discomfort during or after the procedure. Techniques and illustrative radiographs are presented. TBG provides a useful adjunct to endoscopy.

Spiral CT with multiplanar and three-dimensional reconstructions accurately predicts tracheobronchial pathology

BACKGROUND

This study was designed to evaluate the clinical accuracy of multiplanar reconstructions and three-dimensional shaded surface displays compared with conventional transaxial computed tomography, bronchoscopy, and surgical pathologic findings.

METHODS

Transaxial computed tomographic images, two-dimensional nonstandard multiplanar reconstruction images, and three-dimensional images obtained from patients with tracheobronchial disease were prospectively evaluated for the relationship to adjacent structures, lesion characterization, and surgical anatomic correlation before invasive procedures.

RESULTS

Compared with conventional transaxial computed tomographic images, multiplanar reconstructions and three-dimensional shaded surface displays provided a correlative map of bronchoscopic and surgical anatomy in patients with benign and malignant tracheobronchial pathology. The longitudinal extent of abnormalities are better demonstrated on the multiplanar reconstruction and three-dimensional images, whereas the transverse extent of disease and relationships to adjacent structures were better shown on axial computed tomographic sections.

CONCLUSIONS

Three-dimensional and multiplanar two-dimensional images are additive to transaxial computed tomography for evaluation of diseases involving the central airways. They are beneficial for planning invasive procedures. More importantly, they provide consistent, highly accurate measurements for routine follow-up and for future clinical trials.

Tracheobronchial tree: three-dimensional spiral CT with bronchoscopic perspective

The purpose of this report is to describe an original 3D technique that permits bronchoscopic perspective simulations of the tracheobronchial tree on an affordable workstation. Software based on surface shading was developed to permit navigation through the central airways using spiral CT data. Multiplanar reformations are displayed simultaneously with the virtual bronchoscopy simulations to give information about tissues surrounding the airways. Two clinical examples are reported to illustrate the value of this advanced computer technique.