Anterior Junction Line Research Articles

Fascial structure of the anterior mediastinum: the surgical figure of the sternopericardial ligament and the role of affixing the thymus to the pericardium.

The fascial anatomy of the anterior mediastinum has not been thoroughly investigated. Only the sternopericardial ligament (SPL) has been defined and is often described as two independent tendons. However, these descriptions differ from our observations of thoracic surgery. Here, we aimed to precisely investigate the fascial anatomy, particularly the SPL, of the anterior mediastinum. We surgically and radiologically observed and analyzed the fascial anatomy of the anterior mediastinum in patients who underwent surgery for anterior mediastinal disease at our institution between July 2009 and August 2018. A total of 55 thoracoscopic surgeries were performed. We observed a sagittal layer of fibrous tissue bridging the pericardium and sternum, in addition to the well-known fascial layers. Behind the lower bifurcation of the thymic glands, the thymic capsule was firmly fixed to the pericardium around the anterior aortopulmonary trunk. It thickened locally, formed a small white stripe, and occasionally deformed the pericardium by pulling it anteriorly. No other tendon-like structure was observed. Our observation of the SPL showed differences from classical descriptions. The SPL is a sagittal fibrous collection showing a unique figure. Part of the SPL is thickened behind the thymus, anchoring the thymus to the pericardium in the midline. The SPL is part of the bottom of Grodinsky's Space 3 in the thorax. The SPL is visible in radiologic images, such as the anterior junction line on a plain chest radiograph.

Correlation of quantitative and qualitative parameters of high-resolution computed tomography with pulmonary function test for diagnosing and assessing the severity of obstructive pulmonary disease.

PurposeThe aim of the study was to evaluate the role of high-resolution computed tomography (HRCT) in the prediction of presence and severity of chronic obstructive pulmonary disease (COPD), based on the pulmonary function test (PFT), to correlate the various quantitative and qualitative indices of COPD in HRCT with PFT values, and to derive at the threshold values for various quantitative HRCT indices of COPD.Material and methodsA one-year retrospective and prospective evaluation of the HRCTs of 90 cases and 38 controls was performed. Quantitative and qualitative parameters of COPD were assessed in HRCT and were correlated with PFT.ResultsAmong the qualitative parameters, significant correlation with spirometry was found with the qualitative scoring for emphysema and presence and inhomogeneous attenuation. Among the quantitative indices, anterior junction line length, thoracic cage ratio at both aortic arch and inferior pulmonary vein level, thoracic cross-sectional area/[height]² at the aortic arch were found to have good correlation with spirometry. There was significant strong correlation of anterior junction line length and tracheal index with residual volume/total lung capacity (RV/TLC). The threshold values of chest X-ray and HRCT quantitative parameters were calculated and were found to be lower than those of the western population.ConclusionHRCT has a definite role in the diagnosis of COPD and can be used to predict the severity of emphysema.

Computed tomography of solitary fibrous tumor of the pleura abutting the mediastinum: A diagnostic challenge

Background:Solitary fibrous tumor of the pleura (SFTP) arising from the mediastinal pleura may be confused with primary mediastinal tumors. We studied the computerized tomographic (CT) findings of patients with SFTP that could suggest a diagnosis of SFTP.Materials and Methods:At our hospital from January 1995 to June 2012, 39 patients with histologically confirmed SFTP were surgically treated; seven of them abutting the mediastinal pleura. The study group included seven patients aged between 53 and 81 years. Baseline CT scans were retrospectively reviewed to identify radiological findings suggestive of SFTP including: (1) smooth and sharply delineated contours; (2) obtuse, acute, or tapering angles between the lesion and the mediastinum depending on the size; (3) homogeneous soft-tissue attenuation; (4) “geographic pattern” due to the contemporary presence of large vessels, necrosis, and calcifications; (5) displacement of the lung parenchyma; (6) presence of a cleavage plane; and (7) absence of lymphadenopathy or pleural methastasis.Results:All tumors formed acute angles with the pleura. Six out of the seven presented smoothly tapering margins, three had a “geographic pattern” of attenuation and displaced the anterior junction line; one showed an outside junction line development. Four cases had a clear pleural origin.Conclusions:The possibility of SFTP should be taken into account when a mass abuts the mediastinum projecting inside the thoracic cavity in the presence of an intense and “geographical pattern” of enhancement without lymphoadenopathy or pleural metastasis. These findings assume greater significance in the presence of discrepancy between the size of the lesion and the clinical presentation.

Long term radiological features of radiation-induced lung damage

PurposeTo describe the radiological findings of radiation-induced lung damage (RILD) present on CT imaging of lung cancer patients 12 months after radical chemoradiation. Material and methodsBaseline and 12-month CT scans of 33 patients were reviewed from a phase I/II clinical trial of isotoxic chemoradiation (IDEAL CRT). CT findings were scored in three categories derived from eleven sub-categories: (1) parenchymal change, defined as the presence of consolidation, ground-glass opacities (GGOs), traction bronchiectasis and/or reticulation; (2) lung volume reduction, identified through reduction in lung height and/or distortions in fissures, diaphragm, anterior junction line and major airways anatomy, and (3) pleural changes, either thickening and/or effusion. ResultsSix patients were excluded from the analysis due to anatomical changes caused by partial lung collapse and abscess. All remaining 27 patients had radiological evidence of lung damage. The three categories, parenchymal change, shrinkage and pleural change were present in 100%, 96% and 82% respectively. All patients had at least two categories of change present and 72% all three. GGOs, reticulation and traction bronchiectasis were present in 44%, 52% and 37% of patients. ConclusionsParenchymal change, lung shrinkage and pleural change are present in a high proportion of patients and are frequently identified in RILD. GGOs, reticulation and traction bronchiectasis are common at 12 months but not diagnostic.

Radiographic evaluation of mediastinal lines as a diagnostic approach to occult or subtle mediastinal abnormalities

The mediastinal lines visible at conventional radiography represent the interfaces between the mediastinum and adjacent lung parenchyma. Preservation, obliteration, thickening and distortion of these lines represent the key to detecting and localising mediastinal abnormalities on chest radiographs. The learning objectives of this review are to: illustrate radiographic anatomy of the mediastinum with particular attention to mediastinal lines; describe radiographic signs that allow identification of mediastinal abnormalities that are difficult to detect on conventional chest radiographs; describe findings that help localise abnormalities in the anterior, middle or posterior mediastinum. The anterior junction line obliteration, the hilum overlay sign, the preservation of the posterior mediastinal lines and the silhouette sign with the right cardiac border are radiographic signs that allow identification and localisation of anterior mediastinal lesions. Widening of the right paratracheal stripe, distortion of the azygo-oesophageal recess and the convex border of the aortopulmonary window indicate the presence of a middle mediastinal abnormality. Thickening, distortion or disruption of paraortic and paraspinal lines and posterior junction line obliteration are caused by posterior mediastinal lesions. Knowledge of normal radiographic mediastinal anatomy and mediastinal lines is crucial to identifying subtle mediastinal abnormalities that can be easily missed on conventional radiography. Moreover, this approach allows identification of the involved mediastinal compartment on chest radiographs, thereby directing the most appropriate further diagnostic workup.

Automated lung segmentation for thoracic CT: Impact on computer-aided diagnosis 1

Automated lung segmentation in thoracic computed tomography scans is essential for the development of computer-aided diagnostic (CAD) methods. A core segmentation method may be developed for general application; however, modifications may be required for specific clinical tasks. An automated lung segmentation method has been applied (1) as preprocessing for automated lung nodule detection and (2) as the foundation for computer-assisted measurements of pleural mesothelioma tumor thickness. The core method uses gray-level thresholding to segment the lungs within each computed tomography section. The segmentation is revised through separation of right and left lungs along the anterior junction line, elimination of the trachea and main bronchi from the lung segmentation regions, and suppression of the diaphragm. Segmentation modifications required for nodule detection include a rolling ball algorithm to include juxtapleural nodules and morphologic erosion to eliminate partial volume pixels at the boundary of the segmentation regions. For automated lung nodule detection, 4 of 82 actual nodules (4.9%) were excluded from the lung segmentation regions when the core segmentation method was modified compared with 14 nodules (17.1%) excluded without modifications. The computer-assisted quantification of mesothelioma method achieved a correlation coefficient of 0.990 with 134 manual measurements when the core segmentation method was used alone; correlation was reduced to 0.977 when the segmentation modifications, as adapted for the lung nodule detection task, were applied to the mesothelioma measurement task. Different CAD applications impose different requirements on the automated lung segmentation process. The specific approach to lung segmentation must be adapted to the particular CAD task.

Mediastinal interfaces and lines in children: radiographic-CT correlation.

Various mediastinal interfaces and lines are well known in adults, but not fully understood in children. To review the mediastinal interfaces and lines on plain radiographs in the paediatric age group with CT correlation. Soft copies of 195 sets of CT examinations and concurrent chest radiographs in 180 paediatric patients (age 1 month to 15 years) were retrospectively reviewed. The frequency of visualisation and the anatomical basis of the mediastinal interfaces and lines were assessed. The evaluated mediastinal interfaces and lines were superior vena cava interface, descending aorta interface, left paraspinal interface, azygoesophageal recess interface, right paratracheal stripe, anterior junction line and posterior junction line. Chest radiographs showed the SVC interface in 161, the descending aorta interface in 155, the left paraspinal interface in 98, the azygoesophageal recess in 94, the right paratracheal stripe in 53, the anterior junction line in 15 and the posterior junction line in 10. Non-visualisation of mediastinal interfaces and lines on plain radiographs was explained by normal anatomical difference compared with the adult and underlying intrathoracic abnormalities when they were correlated with CT. The frequency of visualisation of the SVC interface, descending aortic interface, left paraspinal interface and azygoesophageal recess fluctuated with age, while the frequency of the right paratracheal stripe, anterior junction line and posterior junction line increased with age. Awareness of the frequency of visualisation and the anatomical basis of the mediastinal interfaces and lines in paediatric patients may be helpful for interpretation of chest radiographs.

Pneumomediastinum revisited.

Pneumomediastinum may result from a variety of causes that may be either intrathoracic (eg, narrowed or plugged airway, straining against a closed glottis, blunt chest trauma, alveolar rupture) or extrathoracic (eg, sinus fracture, iatrogenic manipulation in dental extraction, perforation of a hollow viscus [corrected]. The radiographic signs of pneumomediastinum depend on the depiction of normal anatomic structures that are outlined by the air as it leaves the mediastinum. These signs include the thymic sail sign, "ring around the artery" sign, tubular artery sign, double bronchial wall sign, continuous diaphragm sign, and extrapleural sign. In distal esophageal rupture, air may migrate from the mediastinum into the pulmonary ligament. Pneumomediastinum may be difficult to differentiate from medial pneumothorax and pneumopericardium. Occasionally, normal anatomic structures (eg, major fissure, anterior junction line) may simulate air within the mediastinum. Iatrogenic entities that may simulate pneumomediastinum include helium in the balloon of an intraaortic assist device. In addition, pneumomediastinum may be simulated by the Mach band effect, which manifests as a region of lucency adjacent to structures with convex borders. The absence of an opaque line, which is typically seen in pneumomediastinum, can aid in differentiation. Computed tomographic (CT) digital radiography and conventional CT can also be helpful in establishing or confirming the diagnosis.

A Case Report of Displaced Anterior Junction Line Mimicking

A Case Report of Displaced Anterior Junction Line Mimicking

Can Anterior Junction Line be Used to Distinguish Right Middle from Right Upper Lobe on CT Scan?

Can Anterior Junction Line be Used to Distinguish Right Middle from Right Upper Lobe on CT Scan?

Normal position of trachea and anterior junction line on CT.

In unilateral diseases of the chest accompanied by either volume loss or expansion there is mediastinal shift and mediastinal "herniation" of one lung into the opposite hemithorax. This may also be accompanied by changes in the size of the hemithoraces. Although early detection of these changes may be difficult on chest radiography, one can detect all these changes on CT with greater ease. Since the normal range of position of the mediastinal structures on CT and the symmetry of the hemithoraces have not been studied before, we conducted a prospective study of normal chest CT to define the range of position of the trachea and the anterior junction line, as well as the normal range of differences in the parasagittal diameters of the two hemithoraces. The trachea was < or = 1.6 cm to the right and 0.7 cm to the left of midline; the anterior junction line was < or = 1 cm to the right and 2 cm to the left. The hemithoraces were asymmetric in 84%, with the difference in the parasagittal diameters of the two hemithoraces < or = 1.5 cm. These data may help radiologists detect subtle mediastinal shifts and asymmetry in patients with unilateral pleural or pulmonary disease.

CT Measurement of Mediastinal Anterior Junction Line in Emphysema Patients

The anterior junction line (AJL), the sterno-aortic distance and the sagittal thoracic diameter were measured in CT sections at the carinal level in 22 patients with emphysema and 22 controls. The measured distances were all significantly larger in the emphysema patients. An AJL of 3 cm or more and a sterno-aortic distance of 4 cm or more was found in respectively 10 and 16 of the 22 emphysema patients but in none of the control patients.

Ct Measurement of Mediastinal Anterior Junction Line in Emphysema Patients

Ct Measurement of Mediastinal Anterior Junction Line in Emphysema Patients

The anterior junction line: a radiographic sign of bilateral pneumothorax in neonates.

The anterior junction line is a normal anatomic landmark on chest radiographs of healthy adults and older children caused by the visceral and parietal pleurae of the two lungs meeting anteriorly at the midline. It is not seen on chest radiographs of healthy infants. When this sign is identified on the supine frontal view of a neonate, it signifies bilateral pneumothorax. In this situation the line is formed by the meeting of the medial parietal pleurae on each side as they herniate anteriorly in front of the thymus and heart. The sign is best seen when the patient is rotated slightly to the left. It is not seen when there is unilateral pneumothorax or a concomitant pneumomediastinum. Although the anterior junction line is not a highly sensitive indicator of bilateral pneumothorax, it is highly specific and its recognition can promote faster diagnosis.

Frequencies of pleuro-mediastinal lines in healthy subjects. A contribution to the knowledge of the normal roentgen anatomy of the mediastinum (author's transl)

The postero-anterior chest radio-grams of 1.000 consecutive adults with no evidence of intrathoracic diseases were evaluated and the frequencies of the common pleuro-mediastinal lines in four age groups were calculated. The following lines are less frequent in the age (percentages in the youngest group, ages 18-25, and the oldest group, ages 41-65, respectively): posterior lines in the infra-azygos area (51-19%, p less than .001), right paraspinal line (28-8%, p less than .001), left paraspinal line (11-1%, p less than .01), anterior junction line (41-21%, p less than 0.1), and posterior lines in the supraazygos area (86-66%, p less than .05). The incidences of the right paratracheal stripe (76%), of the aortic nipple (4%) and of the double-contour in the supra-aortic area (51%) were independent from age. The physiologic variations of these lines are discussed. The posterior boundaries of the lung in the supraazygos area manifest as a right pleuro-esophageal line (36%) or as a posterior junction line (64%). A small sickle-like pleuro-esophageal stripe is found in 9%.