Magnetic resonance imaging in tracheal compression by the innominate artery

Diagnostic Accuracy of Three-dimensional Turbo Field Echo Magnetic Resonance Imaging Sequence in Pediatric Tracheobronchial Anomalies with Congenital Heart Disease

Tracheobronchial anomalies are common in congenital heart disease (CHD), including tracheobronchial stenosis, tracheal bronchus, cardiac bronchus, and bronchial isomerism, which can cause varying degrees of respiratory illness. It is necessary to assess tracheobronchial anomalies and make a preoperative airway evaluation. Multi-slice computed tomography (MSCT) and cardiac magnetic resonance imaging (MRI) are the most effective noninvasive modalities for the diagnosis of CHD and the associated tracheobronchial anomalies. However, MSCT remains an ionizing procedure despite using low dose protocols. The aim of this study was to evaluate diagnostic accuracy of tracheobronchial anomalies in patients with CHD using three-dimensional turbo field echo(3D-TFE) magnetic resonance imaging sequence for preoperative airway evaluation. The results indicated that 3D-TFE provided better image quality as compared to that of 3D-balanced turbo field echo (3D-bTFE), and it can clearly demonstrated the tracheobronchial tree and tracheobronchial anomalies in CHD. This study confirms the clinical value of 3D-TFE in diagnosing tracheobronchial anomalies and supply helpful tracheobronchial information for preoperative strategies and postoperative follow-up.

Anatomical variation in the position of the brachiocephalic trunk (innominate artery) with respect to the trachea: a computed tomography-based study and literature review of Innominate Artery Compression Syndrome

Respiratory compromise due to tracheal compression by the brachiocephalic trunk (BT), a condition first labeled as Innominate Artery Compression Syndrome (IACS), has been controversially attributed to an anomalous origin of this vessel to the left of, and hence crossing, the trachea. The aim of this study was to establish the normal relationship between the BT and trachea in infants, children, and young adults without obstructive respiratory symptoms. One hundred and eighty-one computed tomography (CT) examinations of the thorax, in three age groups, were reviewed. In axial cross section, the origin of the BT from the aortic arch was identified. The BT origin, with respect to the trachea, was recorded as for a clock face, approximated to the nearest half hour. There were 62 CTs in Group 1 (1 day to 3 years of age), 48 CTs in Group 2 (10-15 years), and 71 examinations in Group 3 (20-40 years). In 96.8% of Group 1, 91.7% of Group 2, and 74.6% of Group 3 the BT origin was to the left of the trachea, between the half past twelve and 3 o'clock positions. The BT origin occurred more the left in Group 1 when compared with the other two groups (P < 0.001). An origin of the BT to the left of the trachea is a normal finding in children and young adults without obstructive respiratory symptoms. There is a tendency for the origin to become progressively more rightward with age.

The role of magnetic resonance imaging in the assessment of suspected extrinsic tracheobronchial compression due to vascular anomalies

AIMS

To evaluate the role of magnetic resonance imaging (MRI) in the assessment of children with suspected extrinsic tracheobronchial compression due to vascular anomalies.

METHODS

Retrospective case note review in a tertiary referral centre. Twenty nine children who underwent dynamic laryngotracheobronchoscopy (DLTB) and were found to have a clinical suspicion of extrinsic tracheobronchial compression were evaluated. All subsequently underwent thoracic MRI within 10 days. The findings on endoscopy were compared to those of MRI, and where performed, echocardiography, aortography, and surgery.

RESULTS

There were 17 males and 12 females (mean age 5 months, range 28 weeks gestation to 60 months). The most common presenting features were stridor and cyanotic episodes. MRI showed abnormalities in 21 patients. There were five vascular rings (three double aortic arches and two right aortic arches) and 11 cases of innominate artery compression. Other vascular anomalies noted included aberrant right subclavian artery and aneurysmal left pulmonary artery. Echocardiography was generally found to be unhelpful in the diagnosis of extra-cardiac vascular abnormalities. Angiography was subsequently conducted in eight children; findings agreed with those shown on MRI. Surgery was performed on all five vascular rings, one innominate artery compression, and one aneurysmal left pulmonary artery. Surgical findings were also compatible with the preoperative MRI.

CONCLUSIONS

This study shows the successful use of MRI as the initial imaging modality in endoscopically suspected extrinsic vascular compression of the upper airway. It enables accurate delineation of vascular anomalies and, unlike aortography, is non-invasive and does not require the use of contrast media.

Congenital vascular anomalies and persistent respiratory symptoms in children

Congenital cardiovascular anomalies are a rare but treatable cause of stridor in the paediatric population. Despite this, we and the authors of other series have found a delay in referral for endoscopic diagnosis. The duration of symptoms prior to endoscopic diagnosis ranged from 6 weeks to 10 years. It has been estimated that up to 3% of the population have congenital anomalies of the aortic arch complex and we feel that many patients currently being diagnosed as having recurrent croup or atypical asthma must be excluded from this group. We had 16 cases of congenital vascular anomalies causing tracheobronchial compression. Fifteen were due to innominate artery compression and one was due to a double aortic arch. Presenting symptoms included stridor (100%), persistent cough (75%), chronic dyspnoea (75%), reflex apnoea (60%), recurring respiratory tract infections (56%) and dysphagia (25%). Direct laryngoscopy and bronchoscopy was diagnostic in all cases and is our investigation of choice. Eleven underwent aortopexy (69%), one had division of the non-dominant aortic arch (6%) and four were managed conservatively (25%). They were followed for up to 9 years post-operatively and 75% had complete resolution of their symptoms. We feel that only a high clinical index of suspicion will enable these potentially fatal anomalies to be diagnosed.