Role of imaging in pediatric chest disorder by dr. rushabh shah

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  • 2. INTRODUCTION Pediatric chest radiology is a complex subject and hence a full understanding of all the relevant pathologies is necessary. Clinically the pediatric patient with a thoracic disorder usually presents with fever, wheezing, shortness of breath, tachypnea , hoarseness, stridor, cough with or with out expectoration, feeding problems in newborn patients etc. However, these signs and symptoms of thoracic disorders in pediatric patients are relatively non-specific and often caused by multiple disorders of varying pathogenesis. For example, wheezing can be caused by infection (viral or bacterial), toxic exposure (inhalation), trauma (aspirated foreign body) or congenital anomalies (such as tracheal compression by a vascular ring, such as a double aortic arch). Radiation exposure in the first 10 years of life is estimated to produce a risk of total aggregated detriment 5–7 times greater than exposure after the age of 50. The role of diagnostic imaging is to provide the clinician probable underlying etiology of the patients’ symptomatology with the knowledge of the relative advantages and disadvantages of the various modalities for the wide range of disorders in infants and children keeping the dosage of radiation minimum to the patient. 2
  • 3. AIMS AND OBJECTIVES (1) To describe different modalities available for imaging of pediatric chest with their advantages and disadvantages. (2) To present a brief overview of the various chest pathologies in neonate and children (3) To consider radiological appearances of various chest pathologies (4) To discuss current approaches for radiologic analysis and diagnosis of these pathologies (5) To consider role of imaging for providing anatomical operative planes for surgeons. 3
  • 4. ANATOMY OF LUNG THE LUNGS Each lung is divided into lobes surrounded by pleura. There are two lobes on the left: the upper and lower, separated by the major (oblique) fissure; and three on the right: the upper, middle and lower lobes separated by the major (oblique) and minor (horizontal) fissures. The fissures are frequently incomplete, particularly medially, containing localized defects which form an alveolar pathway for collateral air drift and the spread of disease. For a fissure to be visualized on conventional radiographs, the X-ray beam has to be tangential to the fissure. In most people, some or all of the minor fissure is seen in the frontal projection, but neither major fissure can be identified. In the lateral view, both the major and minor fissures are often identified, but usually only part of any fissure is seen; in fact, it is very unusual to see both left and right major fissures in their entirety. The major fissures have similar anatomy on the two sides. They run obliquely anteriorly and inferiorly from approximately the fifth thoracic vertebra to pass through the hilum and contact the diaphragm 0–3 cm behind the anterior costophrenic angle. The minor fissure fans out anteriorly and laterally from the right hilum in a horizontal direction to reach the chest wall. On a standard chest radiograph, the minor fissure contacts the chest wall at the axillary portion of the right sixth rib. THE CENTRAL AIRWAYS The trachea is a straight tube that, in children and young adults, passes inferiorly and posteriorly in the midline. In subjects with unfolding and ectasia of the aorta the trachea may deviate to the right and may also bow forward. In cross-section the trachea is 4
  • 5. usually round, oval, or oval with a flattened posterior margin. The trachea divides into the two mainstem bronchi at the carina. In children the angles are symmetrical. The main stem bronchi further divide into lobar bronchus and then into segmental bronchus dividing lungs into segments. Nomenclature approved by the Thoracic Society is given as below: UPPER LOBE Right Left 1. Apical bronchus 1. Apicoposterior bronchus 2. Posterior bronchus 2. Anterior bronchus 3. Anterior bronchus MIDDLE LOBE/LINGULA 4. Lateral bronchus 4. Superior bronchus 5. Medial bronchus 5. Inferior bronchus LOWER LOBE 6. Apical bronchus 6. Apical bronchus 7. Medial basal (cardiac) 8. Anterior basal bronchus 8. Anterior basal bronchus 9. Lateral basal bronchus 9. Lateral basal bronchus 10. Posterior basal bronchus 10. Posterior basal bronchus 5
  • 6. MODALITIES FOR PEDIATRIC CHEST IMAGING CHEST X RAY: - TECHNICAL FACTORS, VARIATIONS AND ARTEFACTS Chest radiograph is usually the first imaging modality used for thoracic signs and symptoms. • Technical Factors of chest x ray in pediatric patient A. LUNG VOLUME:- Findings of a good inspiratory film: • Heart projects below the dome less than 1/3rd • Flat domes of diaphragm on frontal view • Vertically oriented hemidiaphragms on lateral view • Anterior 6th / 7th rib crossing the diaphragm • Triangle of air behind heart B. POSITION OF THE PATIENT:- In supine position, the vascular supply to upper and lower lobes is equal since gravity has no effect as compared to child sitting or standing when due to gravity upper- lobe vessels are less distended than lower-lobe vessels. Findings of a rotated film:- • Anterior ribs- not equidistant from ipsilateral pedicles • Medial aspects of clavicles- asymmetrical in relation to midline • Position of carina to the left of right pedicles (normally approx. right pedicles) • Ribs seen posteriorly • Differential aeration of lung field 6
  • 7. C. PROJECTION OF THE X RAY:- In supine film, there is inherent magnification of mediastinal structures and absence of the effect of gravity on pulmonary vascularity. D. ADEQUACY OF EXPOSURE:- In properly exposed film, the detailed spine and pedicle through the heart and the pulmonary vessels in the peripheral lung are visible. If only the spine but not the pulmonary vessels are seen, the film is overexposed. E. THYMUS:- The mediastinum of infants including neonates appears abnormally wide or misshapen, due to the variable appearance of the thymus. Enlargement of the thymus may occur after an acute illness—normal ‘thymic rebound’, and may simulate mediastinal mass. Features of normal thymus : lower attenuation structure allowing vessels to be seen through it, uniform reflectivity on US and not displacing the trachea. • Technical factors of chest x ray in neonate: 1. PA projection: - difficult to take in neonate. 2. AP projection: - supine, tube–film distance is 36–40 in. 3. Lateral projection :- by turning patient to one side “cross table lateral view”- particularly for free air . The normal appearance of neonatal chest differs from older pediatric chest. It is almost cylindrical in shape, having horizontal ribs with higher anterior portions of diaphragm. • Difficulties in interpretation of neonatal chest x ray due to technical and anatomical factors:- 1. A normal neonate breathes at a rate of 30–50/min, and it is therefore difficult to get a “good inspiratory film”. 2. The trachea in the neonate and young infant is “too long” for the contracted chest in expiration and therefore buckles. 7
  • 8. 3. Skin folds can be seen as curvilinear densities projecting over the lung bases laterally mimicking a pneumothorax. 4. A rotated film can simulate abnormal mediastinal shift. 5. “Ductus bump”:- Frontal views in an infant shows “bump” in the upper mediastinum caused by the superimposition of the main pulmonary artery, left pulmonary artery, and ductus arteriosus. The latter gradually retracts, and the mass disappears by 3rd day. • Neonatal Chest with Normally Positioned Tubes and Lines The position of the tubes and lines on a neonatal chest x-ray should be: 1. Nasogastric tube tip: within the stomach 2. Feeding tube tip: within the third portion of the duodenum 3. Central venous line tip From subclavian/jugular/antecubital approaches: within superior vena cava. From a femoral approach: low in the inferior vena cava (below L3) or at the junction of the inferior vena cava and right atrium 4. Umbilical artery catheter (UAC) tip: either high (between T7 and T11) or low (Below L3). On the lateral film the UAC dips into the pelvis from the umbilicus through one of the paired umbilical arteries and then courses through the internal iliac artery and then into the common iliac artery and aorta. UAC projects over the left side of the spine on the AP film. 5. Umbilical venous catheter (UVC) tip: at the junction of the right atrium and the superior vena cava.On the lateral film the UVC extends cephalad from the umbilicus through the umbilical vein and then courses into the portal vein, across the ductus venosus, and into the inferior vena cava. The UVC projects over right side of the spine on the AP film. 8
  • 9. FLOUROSCOPY It has limited role due to high radiation dose, but may be useful for assessment of diaphragmatic movement, air trapping, oesophageal lesions. ULTRASONOGRAPHY USG should be considered as a second line modality for the evaluation of those processes which are intrathoracic but peripheral in location as there is no sound transmission through air filled lungs3 . USG is useful for presence and characterisation of pleural effusions, chest wall leisons, peripheral lung lesions and anterior mediastinal mass in young childern. COMPUTED TOMOGRAPHY CT is often considered when radiography is insufficient for the diagnosis or for surgical planning. CT provides excellent global assessment of thoracic and intrathoracic structure with the help of IV contrast media. HRCT provides early information regarding diffuse pulmonary parenchymal disease. Relative disadvantages are need of sedation in younger childern, artefacts due to cardiac and respiratory motions , less tissue contrast due to paucity of mediastinal fat and risks of IV contrast. MRI MR imaging is considered as a problem solving tool in evaluation of chest wall, spinal, paraspinal region and cardiovascular disease. NUCLEAR MEDICINE Nuclear medicine help delineate cardiac function, lung ventilation/perfusion, pulmonary embolism and inflammtory lung disease. 9
  • 10. CLASSIFICATION OF PEDIATRIC CHEST PATHOLOGIES Α) MEDICAL CONDITIONS:- NEONATE INFANTS AND YOUNG CHILDERN Transient tachypnea of newborn Infections Hyaline membrane disease AIDS Aspiration syndrome Aspiration pneumonia Neonatal pneumonia Hilar adenopathy Pulmonary Hemorrhage Cystic fibrosis Complication of Therapy- Interstitial lung disease Early:- Pneumothorax Pneumomediastinum Pulmonary interstitial emphysema Late:- Bronchopulmonary dysplasia Wilson- Mikity syndrome Β) SURGICAL CONDITIONS:- 1. LUNG:- Congenital:- Abnormal lung bud development: - Congenital lobar emphysema Unilateral pulmonary agenesis Pulmonary hypoplasia and Hypogenetic syndrome Abnormal separation of lung bud: - Sequestration Hamartomatous lesions: - Congenital cystic adenomatoid Malformation (CCAM) Lung cysts Hamartoma Vascular anomalies Congenital AV malformation 10
  • 11. Infective:- Lung abscess Hydatid cyst Neoplastic:- Metastasis Pulmonary sarcoma/blastoma 2. AIRWAY:- Congenital:- Tracheo-esophageal fistula Tracheal stenosis Tracheomalacia Infective:- Bronchiectasis Obstruction:- Foreign body inhalation 3. MEDIASTINUM:- Developmental:- Lymphangioma Anterior thoracic meningocele Duplication cyst Mediastinal mass: described below 4. PLEURAL AND CHEST WALL:- Infective: - Empyema Neoplastic:- PNET (Primitive neuroectodermal tumor) Ewing’s sarcoma Rhabdomyosarcoma 5. DIPHRAGM:- Diaphragmatic eventration Diaphragmatic herniation 11
  • 12. CLASSIFICATION OF MEDIASTINAL MASSES For classification of mediastinal masses, mediastinum is divided into three compartments. For this various classifications have been given but most common followed radiographically is as mentioned below: Anterior: - The space in front of the heart and great vessels Middle: - The space between the anterior and posterior mediastinal components, including heart, airway, esophagus, and lymph nodes Posterior: - Everything behind a line that passes through 1 cm behind anterior border of vertebral body 12
  • 13. Category Anterior Middle Posterior Congenital Normal thymus Cystic Hygroma Morgagni Hernia Foregut Duplication Cyst Bronchogenic Cyst Esophageal duplication cyst Neurenteric cyst Cystic Hygroma Hiatus hernia Achalasia Cardiomegaly Vena caval enlargement Bochdalek Hernia Foregut cysts Hiatal Hernia Inflammatory Lymphadenopathy Lymphadenopathy Tuberculosis, sarcoidosis, Histoplasmosis, Metastasis Lymphoma Paravertebral abscess Neoplastic Lymphoma & leukemia Germ cell tumours Thymoma Thymolipoma Extension of those arising from Anterior mediastinum Ganglion cell tumour Lymphoma Mesenchymal tumours Vascular Aortic aneurysm Aortic aneurysm Azygous & hemiazygous enlargement Other Paravertebral Hematoma Extramedullary Hematopoesis 13
  • 14. RADIOLOGICAL APPEARANCES OF COMMON PEDIATRIC CHEST DISEASES Respiratory distress syndrome( RDS, or hyaline membrane disease, HMD):- a. Preterm b. Diffuse ground glass opacities- fine reticular shadows throughout c. Accentuation of air bronchogram d. Confluent shadows obscuring diaphragmatic and cardiac contour e. Effusion is very rare f. Traditionally low volume Neonatal pneumonia:- a. Any pattern possible (focal opacity, multifocal opacity, focal or diffuse ground glass opacities) b. Asymmetry of the findings is more favouring c. Normal or increased lung volume d. Term or preterm appearing child e. Small to moderate pleural effusion is much more common Aspiration syndromes: can be amniotic fluid alone, blood, or fluid with meconium—the latter results in most severe changes) a. Generally, term neonate b. Patchy areas of hyperinflation and atelectasis (or other heterogeneous opacities) c. Pneumothorax or pneumomediastinum d. Effusion is not typical Transient tachypnea of the newborn (TTN) or retained foetal lung fluid a. Term neonate b. Increased lung volume c. Streaky, predominantly central opacities d. Usually symmetrical, more on right side e. Small pleural effusion f. Radiographic resolution by 48-72 hrs of age 14
  • 15. Pneumothorax:- Air in pleural cavity, usually anterior and medial to lung Increased radiolucency of hemithorax Increased sharpness of mediastinal border from superior extent to diaphragm Compression of thymus Pneumomediastinum:- Air in mediastinum, able to dissect into various spaces Not associated with respiratory distress Oval or round lucency on either side of diaphragm Not extend to diaphragm due to its anterior location Elevation of thymus Pulmonary interstitial emphysema (PIE):- Air leaking into the interstitial space and spreading throughout the lymphatics and along the perivascular sheaths Radiological appearance is of small bubbles of air radiating out from the hilum. When severe, the lungs are overinflated. PULMONARY INFECTIONS:- Most common cause of respiratory related morbidity in pediatric patient. Etiologies acco. To different ages:- Congenital(at birth) Newborn(less than 1 mth) Group B streptococcus Group B streptococcus Gram –ve organisms Gram –ve organisms Congenital viruses Staph. Aureus Toxoplasmosis Chlamydia Trachomatis Listeria Monocygenes Pneumocystis carinii Viruses 15
  • 16. Early years (1 to 5 yrs) Older children (more than 5 yrs) Viruses Viruses Streptococcus pneumoniae Mycoplasma pneumoniae H. Influenzae Strepto. Pneumoniae Staph. Aureus H. Influenzae Radiological appearance: X RAY:- Bacterial Pneumonia Focal (more common than multifocal) opacity Ill-defined margin Air space involvement: air bronchogram (hallmark of airspace disease) Lobar or segmental distribution Normal lung volumes Associated pleural effusion or empyema Hilar adenopathy Viral pneumonitis Generally symmetric: centralized or diffuse Interstitial Involvement Peribronchial thickening Streaky hilar opacities On lateral, these superimpose to create full looking hila Pitfall: may look like adenopathy Hyperinflated lungs Atelectasis Hilar adenopathy 16
  • 17. Appearance specific to organism:- Staph. Aureus: - Severe, necrotizing, segmental and lobar consolidation Associated with cavitation and pneumatocele Associated with pleural effusion and empyema ‘Ghost cavities’ may persist after resolution Pertussis: - Classical finding is of shaggy heart border due to sublobar Consolidation Pneumocystis carinii pneumoniae:- Most common opportunistic infection in children with HIV Affects children between 3 months to 7 months Radiographic appearance includes increased interstitial markings, which spread from an initial perihilar distribution to the periphery. Alveolar opacities often accompany progression of interstitial disease Round pneumonia:- In children less than 8 years of age in whom the collateral pathways of circulation are not well developed, pneumonia can have a very round appearance and mimic a mass8 .In a child with fever and appropriate symptoms, round pneumonia should be the primary diagnosis when a round mass is seen on chest X ray. Follow-up after antibiotic therapy needed to exclude an underlying mass, such as a bronchogenic cyst. Most cases are related to Streptococcal pneumoniae infection. Fungal infection:- usually non specific, but hallmark is the prescence of nodules6 . USG:- The role of USG for in infectious processes is primarily limited to evaluation of the presence and of characteristics of pleural fluid, or in confirming that an opacity is parenchymal and not pleural. 17
  • 18. CT:- CT is used in evaluation of parenchymal infections that are not responsive to therapy and associated with progressive consolidation or development for large pleural fluid collection. CT examination is the second-line modality in evaluation of pulmonary infectious process following serial radiographs. Findings include necrosis, cavitation, pleural abnormalities (bronchopleural fistulae, fluid collections) or chest wall involvement. IV contrast-enhanced CT is useful to define adjacent vessels, potential enhancement of viable lung which may be atelectatic, or absence of enhancement of consolidated lung suggesting necrosis. It also gives the best assessment of the nature and extent of infection, including the presence of pneumatocele formation. PULMONARY TUBERCULOSIS:- Lung is the most commonly involved organ by Mycobacterium. Radiological manifestation includes:- Primary pulmonary complex: Consolidation:- usually single, < 2cm, homogneous with illdefined margins Tuberculoma:- round/oval mass like opacity, more in upper lobes and on right side Satellite lesions in 80%, cavitation and calcification in 10 to 50% Lymphnode:- In 96% of pts. On same side, usually hilar or bronchial, then others are involved CT usually shows > 2cm in size with central area of low density with rim enhancement of irregular thick wall with preserved or obliterated perinodal fat. Other patterns are homogenous enhancement, uniform rim enhancement. Airway involvement:- Atelectesis due to either primary endobronchial TB or extrinsic compression by lymph node. Pleural involvement:- Pleural effusion – absent or mild 18
  • 19. Progressive primary disease:- Consolidation:- lobar or segmental Collapse Pleural involvement:- may be massive, can lead to empyema Bronchogenic spread:- confluent multiple foci of alveolar shadows Miliary tuberculosis: - tiny, pinpoint opacities uniformly through out both lung Fields, more at bases. Post primary lesion:- Calcification, both parenchymal and nodal Fibrosis ASTHMA:- Should be performed to exclude complication Findings are signs of overinflation and bronchial wall thickening and peribronchial cuffing. CYSTIC FIBROSIS:- Autosomal recessive disease associated with chronic pulmonary sepsis and malabsorption (pancreatic exocrine insufficiency, cirrhosis, and gut involvement). Early radiographic features include air trapping and bronchial wall thickening, features that are radiographically indistinguishable from asthma or recurrent pneumonia. Later a diffuse interstitial pattern, bronchiectasis, cyst formation and changes of pulmonary hypertension occurs. LOBAR COLLAPSE:- It is one of the common radiological manifestation of various pediatric chest conditions. When these lobes collapse, they retain their hilar attachment, and the other lobes often expand to compensate. The patterns of the lobar collapse are identified in two ways: by seeing the collapsed lobe in a recognizable pattern, and by noticing subtle shifts of intrathoracic structures such as the fissures 19
  • 20. between lobes of the lung and loss of normal radiological borders (silhouette sign) Things to determine when an opacity is seen that appears to be a lobar collapse to identify the lobe involved and its probable etiology: ● Shift of mediastinum ● Deviation of major and minor fissure ● Silhouette of normal structures e.g. cardiac borders, diaphragmatic contour ● Pulled up or pulled down hila ● Elevation of dome of diaphragm A common cause of lobar collapse in children is mucus plugging in postoperative and asthmatic patients. Always look for foreign bodies by carefully examining the right and left main-stem bronchi. Masses such as lymph nodes (due to tuberculosis, other infections, or lymphoma), or extrinsic masses such as bronchogenic cysts, can also cause lobar collapse. CONGENITAL LUNG MALFORMATIONS Solid mass-like Air-filled mass-like Bronchogenic cyst CCAM Pulmonary sequestration Congenital diaphragmatic hernia Rarely, CCAM: more often air-filled CLE Diaphragm elevation Pneumatocele CONGENITAL LOBAR EMPHYSEMA (CLE):- Age & Sex: - less than 6 mths, male preponderance Symptoms and signs:- Respiratory distress Chest x ray:- Primary imaging tool Predilection for the upper lobes and right middle lobe. 20
  • 21. Sequence of appearance: within 24 hrs, alveoli appear distended and opaque, then gradually distends with air and shows acinar shadowing, a reticular interstitial pattern and finally becomes hyperlucent. Adjacent lobes are compressed, the ipsilateral hemidiaphragm is depressed, and rib spacing is increased. Differntial diagnosis:- Attenuated lung markings seen in the overinflated lobe, helps to differentiate it from a pneumothorax. With a pneumothorax, the lung collapses around the hilum. Other differential diagnosis include secondary lobar emphysema; congenital lung cysts (including type I CCAM); pneumatoceles; and the Swyer-James syndrome (unilateral hyperlucent lung). CT scans:- demonstrates involved lobes or segments.The affected lobe is overdistended and hypodense, with attenuated vascular markings. Peripherally situated septa and vascular structure20 . No cysts or soft tissue are seen. CT is useful to exclude secondary causes of lobar overinflation,i.e a vascular ring or a mediastinal mass lesion. CCAM(Congenital cystic adenomatoid malformation):- CCAM results from a failure of normal bronchoalveolar development.There is communication between the individual cysts within the CCAM and also with the tracheo-bronchial tree. Classification of Stocker11 :- Type I CCAMs: Most common, approx. 70%21 contain one or more cysts measuring over 2 cm in diameter, surrounded by multiple smaller cysts. Appearance:- A multicystic lesion,although there can be one dominant cyst 21
  • 22. Mass effect can cause contralateral mediastinal shift, inversion of the ipsilateral hemidiaphragm,and compression and atelectasis of both ipsilateral and contralateral pulmonary lobes. The involved lobe may herniate across the midline to the opposite side Type II CCAMs: 15 o 20% contain cysts measuring up to 2 cm in diameter. Asso. With other anomalies-renal ,cardiac & lung Type III CCAMs: usually contain cysts less than 0.5 cm in diameter seen as a homogeneous, soft tissue density mass. Location:- Equal frequency in the upper and lower lobes, less often in right middle lobe.Typically, they are unilobar, but multisegmental CCAMs have been reported Antenatal ultrasound examinations:- An echogenic mass, which may/ may not contain cysts May be associated with the development of maternal polyhydramnios or fetal nonimmune hydrops fetalis. CT scan:- Document the involved pulmonary segments or lobes appears as a multicystic mass, with few air fluid levels and fluid filled cysts. Overinflation and lack of definite air bronchogram differentiates it from necrotizing pneumonitis2 . Differential diagnosis:- Diaphragmatic hernia ( Intact diaphragm & normal bowel pattern) Pulmonary sequestration CLE Bronchogenic cyst 22
  • 23. SCIMITAR SYNDROME:- Commonly affects right lung, which is hypoplastic and is drained by anomalous vein that extends below the diaphragm to join IVC, hepatic or portal vein. Chest Xray:- Small affected lung with small hilum with ipsilateral mediastinal shift Curved turkish sword continuing below the diaphragm BRONCHOPULMONARY SEQUESTRATION:- Congenital mass of nonfunctioning lung tissue lacking communication with tracheobronchial tree 2 types Intralobar Extralobar Presents with recurrent pneumonia Coincidental mass Systemic bld supply Systemic bld supply Drains into left atrium into systemic veins Have normal pleural covering separate pleural covering Older age infancy Mostly in lower lobe,on left side on left side,conti with diaphragm Features: Spherical or triangular basal opacity, may be associated with emphysema of surrounding lung tissue Demonstration of abnormal vascular supply by angiography, CTA or MRA. Cystic parenchymal lesion can be a presentation. LUNG ABSCESS:- Due to necrosis, suppuration and cavitation in localized infection in lung Early stage:- discrete pneumonic consolidation on chest x ray At this stage, CT may demonstrate low density area in area of consolidation with no air bronchogram in region of abscess Late stage:- Cavitary leison with air fluid level and thick and shaggy wall 23
  • 24. HYDATID CYST:- Due to infestation with Echinococcus CxR:- shows spherical or oval well defined homogenous opacity. May be single, multiple, unilateral or bilateral Rarely calcify. USG shows characteristic cystic mass with floating membranes in lesions abutting chest wall or diaphragm CT or MR shows fluid content of cyst and floating membranes. PULMONARY METASTASIS:- In children, due to Wilm’s tumour, rhabdomyosarcoma, osteosarcoma , ewing’s sarcoma, germ cell tumours, neuroblastoma, lymphoma and leukemia TRACHEO-OESOPHAGEAL FISTULA:- Most important congenital malformation of oesophagus 5 types, H type being commonly associated with respiratory distress Demonstration by injecting contrast at various levels of esophagus BRONCHIECTASIS:- Localized irreversible dilatation of bronchial tree Cystic fibrosis,most important cause in children 3 types:- cylindrical, varicose and saccular CxR:- multiple cystic spaces with/without air fluid level, tramline shadows due to bronchial wall thickening CT(HRCT)- detects type, distribution, severity and extent of disease Cylindrical:- dilated thick walled bronchi towards the periphery On end on along with artery, signet ring sign Varicose:- beaded bronchial lumen Saccular:-marked dilatation of bronchi with cluster of cysts FOREIGN BODY:- 24
  • 25. Most common cause of respiratory distress < 3yrs of age. More on right side. Opaque being 5-15% Findings:- Partial blockade- unilateral hyperlucency due to air trapping and obstructive emphysema Complete Blockade:- atelectasis with mediastinal shift to same side Expiratory films, decubitus films with involved side dependent and fluoroscopy is useful. EMPYEMA:- Due to bacterial infection, secondary to septic pulmonary emboli, lung abscess or spread from adjacent infectious process Fluid rich in protein and tend to loculate CxR:- d/d from lung abscess & consolidation important USG:- septation with echoes within fluid CT:- localize site & extent of fluid collection, determine adequacy of tube drainage, and to d/d between pulmonary and pleural lesion Lenticular , obtuse angle of interface with chest wall and changes with change in position of the patient. Demonstrates “split pleura sign” and compression of adjacent structures. D/D from lung abscess:- round shape, thick irregular wall,acute angle at interface with chest wall and absence of evidence of lung compression, shows air bubbles in wall. Parietal pleural enhancement, parietal pleural thickening greater than 2 mm, extrapleural thickening and increased attenuation of the extrapleural space, and adjacent chest wall edema favours empyema more than transudative effusion in parapneumonic effusion.14,15 . PNET(ASKIN’S and EWING’S SARCOMA) Most common chest wall tumours in children Locally aggressive and associated with rib destruction and pleural effusion19 25
  • 26. Diffucult to d/d between two, only histology is useful. DIAPHRAGMATIC HERNIA:- Bochdalek’s hernia Morgagni’s hernia More on left side More on right side Posterolateral Anteromedial Earlier presentation Late presentation Large in size Small in size Cystic/complex mass(solid mass if x ray has been taken before air enters bowel) in hemithorax with mediastinal shift,failure to visualize stomach, abnormal position of stomach and abdominal viscera and abnormal position of NG tube. D/D from CCAM:- position of stomach normal,in diaphragmatic hernia either stomach is not visualized or central in abdomen. EVENTRATION OF DIAPHRAGM:- d/t thin diaphragm, usually partial involving ½ to 1/3 of hemidiaphragm usually anteromedial portion of right hemidiaphragm CxR:- Elevated hemidiaphragm with smooth hump blending with contour of hemidiaphragm Poor or paradoxical movement MEDIASTINAL MASSES:- Cysts and Cystic Conditions Fat-containing masses True thymic cysts Thymolipoma Germ cell tumours Germ cell tumour (usually mature teratoma) Lymphatic malformation Vascular malformations Lymphoma Thymoma Foregut duplication cysts Calcification Germ cell tumour 26
  • 27. Thymic cysts THYMIC MASSES:- Normal thymus Thymic cysts:- developemntal, unilocular or multilocular Thymoma:- 5-8%, after 10 yrs of age, calcification in 10% GERM CELL TUMORS:- 2 age peaks: 2 yrs and adolescence 80% teratoma and benign, rest others Calcification & areas of fat, displacement of adjacent structure CYSTIC HYGROMA:- Mostly in neck, 10% extend in mediastinum Low attenuation cystic mass with insinuation in surrounding structures NEUROGENIC TUMOURS:- Neuroblastoma (malignant, < 5yrs), ganglioneuroblastoma(5-10yrs) Ganglioneuroma(benign, >10yrs) X ray:- paravertebral soft tissue mass with calcificaiton in 30% Thinning, separation of ribs and enlargement of intervertebral foramina CT:- Calcification in 90%12 , inhomogenous enhancement FOREGUT CYSTS:- Bronchogenic cysts:- Round/oval, unilocular, homogenous water density mass with well defined borders Types:-paratracheal, carinal, hilar and paraoesophageal Oesophageal duplication cyst:- Larger, to the right of midline extending in posterior medistinum Approximately 60% of EDCs are located in the distal third of the esophagus, 17% are in the middle third, and 23% are at the cervical level22 . Neurenteric cyst:- Maintains connection with spinal canal, more on right side 27
  • 28. Vertebral body anomalies are associated. LYMPHOMA Hodgkin’s disease NHL Usually > 10 yrs Any age in children Mostly localized. Mediastinal in 85% Disseminated in > 75% Displacement is more likely Compression is more likely Lung involvement in 10% of cases Pulmonary involvement is higher INTERSTITIAL LUNG DISEASE:- HRCT is the best investigation available for the evaluation of interstitial lung disease in older children. Findings are similar to that of adults: ground glass opacity, tree-in-bud, lobular air trapping, reticular opacities, and centrilobular nodules. Indications of HRCT in children:- Infantile cellular interstitial pneumonitis and pulmonary interstitial glycogenosis Chronic pneumonitis of infancy Persistent tachypnea of infancy Surfectant protein abnormality Systemic disease: glycogen storage disorder, hemosiderosis, connective tissue disorder APPROACH TO EARLY DIAGNOSIS IN PEDIATRIC CHEST X RAY6 Large cystic hemithorax Large lucent hemithorax Large opaque hemithorax CCAM Pneumothorax Pleural fluid CDH Partially obstructed CDH PIE lung CCAM Pneumatocele Compensatory hyperinflation Neoplasm 28
  • 29. REVIEW OF LITERATURE 1. In a 1986 publication, Swischuk LE, Hayden Jr CK9 et al evaluated the ability of radiographic patterns of infection to predict whether or not a child had bacterial pneumonia based on clinical criteria, such as rapid or short duration of illness, high fever, high white blood cell count, and rapid response to antibiotics .There was no analysis for organisms performed. They reported that the radiographic presentation predicted which children meet the clinical criteria for bacterial illness with an accuracy rate of 90%. 2. A study published by Ramnath et al 16 suggested a very simple ultrasound grading system in which parapneumonic effusions were graded as low-grade (anechoic fluid with no septations) or high-grade (presence of echogenic fronds, septations, or loculations) Those patients with high-grade parapneumonic effusions, as demonstrated by ultrasound, and treated with aggressive therapy had a 50% decrease in duration of hospital stay as compared with those who were conservatively managed. 3. In one study done by Donnelly LF, Klosterman LA studying role of imaging in persistent or recurrent pneumonia, IV contrast-enhanced CT identified an underlying suppurative cause of the persistent illness in 100% of patients15,17 . 4.In a study done by Stigers KB, Woodring JH1 et al given lobar predilection of CLE, most common site being left upper lobe(43%) followed by right middle lobe (32%) and right lower lobe (20%). 5. Frush DP, Donnelly LF4 et al concluded that Helical CT is the imaging modality of choice in sequestration in demonstration of systemic arterial supply and characterization 29
  • 30. of lung lesion. They also demonstrated association of other anomalies with extralobar sequestration in 65% of cases they studied. 6. Donnelly LF, Klosterman LA5 et al studied patients with cavitary necrosis and showed that 41% of these patients were detected on x ray as compared to CT. 7. In evaluating trauma, Sivij CJ, Taylor GA7 et al showed that chest trauma is responsible for 25% of deaths occurring in children due to trauma. 8. Siejel MJ10 et al stated that mediastinal lymphnodes generally are not seen on CT or MR in children prior to puberty and their presence should be considered abnormal. 9. Whitsett JA, Pryhuber GS, Rice WR18 et al studied acute respiratory syndrome in neonate and showed that approximately 50% of neonates born between 26 and 28 weeks and 20–30% of neonates born at 30–31 weeks of gestation develop RDS. 10. Conran RM, Stocker JT23 et al studied 50 cases of extralobar pulmonary sequestration and showed its association with type II CCAM in 50% of cases. 11. Macpherson RI22 studied Gastrointestinal tract duplications anomalies and showed distribution of esophageal duplication cyst: 60% in distal third, 17% in middle third and 23% in cervical third. 12. Billmire DF26 et al while studying germ cell tumours showed that Germ cell tumors account for 6% to 18% of mediastinal tumors. 13. Fishman SJ25 et al showed that cystic hygroma are rare causes of mediastinal masses. 30
  • 31. 14. Meza MP, Benson M, Slovis TL24 et al showed of all pediatric mediastinal masses studied, 30% to 40% occur in the posterior mediastinum. Most (85%–90%) of these masses are of neurogenic origin. 31
  • 32. MATERIALS AND METHODS Sixty patients were selected based on clinical suspicion from May2007 to October2009. Patients below the age of 14 years have been considered. All patients underwent chest xray as first line of investigation on bases of symptomatology. Followed by this depending upon the need of the clinician further investigations were carried out. Though heart is within the thoracic cage, I have excluded cardiovascular system from my study to concentrate more over respiratory system problems. Those patients were selected in whom more than one imaging modality was used for the purpose of evaluation of condition. X rays of patients were taken most of the times in PA position with appropriate exposure factors either making the child stand or holding the infant by their parents and keeping them protected with lead aprons. Rest of times supine AP x-ray was taken. US was next investigation in patients having suspected pleural effusion.US was performed on a Esaote, Philips unit, using 3.5 and 5.0 MHz transducers. CT scan was performed when further evaluation was deemed necessary and when the investigation was affordable and accessible to the patient. It was carried out on helical CT unit of Schimazdu, civil hospital, Ahmedabad. MRI was performed on Philips Gyroscan 0.5 T machine for the evaluation of infective process involving spine and spinal canal. Ultrasound guided fluid aspiration was done when indicated. As most of the patients with pediatric chest diseases conservatively treated, they were followed up to know the outcome of the therapy. In surgical conditions,outcome and follow up whenever available were recorded. Imaging findings were correlated with surgical and histopathological findings whenever available. The role of radiology played in each case was critical. 32
  • 33. OBSERVATION AND ANALYSIS Table 1: Age distribution Age group No. of patients Less than or equal to 1 mths 3 1 mth to 1 yr 8 1 yr to 5 yr 24 5yr to 9 yr 17 9yr to 14 yr 8 Total 60 Out of the 60 patients, most common age of presentation with pediatric chest disease is 1 yr to 5 yr(40%). Table 2 : Sex distribution Sex of patient No. of patients Male 41 Female 19 Total 60 Out of studied 60 patients, majority are males (68%) as compared to females (32%). Table 3: Presentation with respiratory symptoms 33
  • 34. Symptom No. of patients Percentage Fever 41 68% Cough with or without sputum production 48 80% SOB or breathing difficulty/ choking 26 43% Chest pain 12 20% Major symptoms in pediatric chest symptomatology are cough with or without expectoration (80%) followed by fever( 68%). Table 4: Etiological classification of pediatric chest pathologies Disease Group No. of Patients Percentage Congenital 10 15 Inflammatory 41 70 Traumatic 1 1.6 Neoplastic 2 3.3 Interstitial 1 1.6 Other 6 10 Total 60 100 In studied patients, major group of disease involving pediatric chest is inflammatory (70%) followed by congenital (15%). Table 5 : Regional involvement of pediatric chest 34
  • 35. Region of chest involved No. of patients Parenchymal 23 Pleural 7 Airway 6 Mediastinum 3 Diaphragm 3 Chestwall 1 Diaphragm and parenchymal 2 Pleural and parenchymal 14 Multicompartemental 1 Total 60 Most common region of chest involved in studied 60 pediatric patients is pulmonary parenchyma (38%) followed by both pleural and parenchymal (23%) and pleural disease(12%). Table 6: X ray – CT correlation in relation to pulmonary and mediastinal pathology PATHOLOGY X RAY CT Airbronchogram 9 16 Soft tissue opacity in patient with consolidation 16 20 Collapse 7 20 Cavity 5 5 Mediastinal shift 12 17 Associated lymph node 0 6 Calcification in lung parenchyma 1 1 35
  • 36. Calcification in mediastinal mass 1 3 Pneumomediastinum 0 1 Table 7:- X ray – CT correlation in pleural pathology Pathology X ray CT Total no. of pt undergoing both x ray and CT with pathology Pleural effusion 15 17 17 Pneumothorax 6 8 8 CT showed effusion and pneumothorax in all patients as compared to x ray demonstrating same in 88% and 75% of patients respectively. Table 8:- X ray – USG correlation in pts with pleural effusion Pleural fluid X ray USG Total No. of pts undergoing both x ray and USG Present 8 12 12 X ray was able to detect pleural fluid in 67% of patients as compared to USG in patients undergoing both x ray and USG. 36
  • 37. Table 9:- USG –CT correlation in pleural collection in pts undergoing both USG and CT* Pleural collection USG CT Fluid present 10 10 Septation 8 0 Echoes 7 0 USG showed presence of septation and echoes in majority of patients as compared to CT which was not able to demonstrate the same in any patient. *- Total number of patients undergoing USG and CT—10 Table 10:- X ray and CT correlation in pts with pleural effusion Pleural fluid X ray CT Present 15 18 X ray demonstrated pleural fluid in 83% of patients as compared to CT in patients undergoing both X ray and CT. Table 11:- X ray and CT demonstrating both pleural and pulmonary pathology Pathology X ray 37
  • 38. Only pleural pathology 6 Only parenchymal pathology 1 Both pleural and pulmonary pathology 7 Total no. of patients detected by CT having both pleural and pulmonary pathology 14 X ray was able to detect both pleural and pulmonary involvement in 50% of patients studied. DISCUSSION In this study, 60 patients of pediatric age group with chest disease were studied by various radiological methods based on clinical methodology. • Most common age being presented with pediatric chest disease is between 1 yr to 5 yr (40%). • Pediatric chest diseases are found to be more common is males in this study (68%). • Most common symptomatology was found to be cough with or without expectoration (80%) and fever (68%). • Among the basic disease groups, the most common disease group is inflammatory 41 cases (70%) followed by congenital 10 cases (15%), foreign body 4 cases (7%), rest comprising of neoplastic (2 cases), interstitial and traumatic and nonneoplastic mediastinal mass (1case each). • In this study, most common region of chest involved were pulmonary parenchyma 23 cases (38%), both pleural and parenchymal pathology 14 cases(23%), pleural pathology 7 cases(12%) and airway involvement 6 cases(10%). Rest comprising of mediastinum and diaphragmatic involvement in 5 cases each. 38
  • 39. Congenital lesions:- • Out of 10 cases of congenital origin, 5 are diaphragmatic in origin, 3 being diaphragmatic hernia and 2 being eventration of diaphragm. Other four are CCAM, CLE, lung aplasia, TOF with esophageal atresia and bronchopulmonary sequestration. • In diaphragmatic hernia, herniation of bowel loops noted in all cases and spleen noted in one case which was better demonstrated on CT. Bowel loops were easily visualized with barium examination. • In CCAM and CLE, CT was useful to determine the lobar involvement and guiding the surgeon. • Esophageal atresia was seen as a curling of IFT in esophagus. There was presence of gas in stomach, so the diagnosis is TOF with esophageal atresia. • One case of bronchopulmonary sequestration appeared as patch of consolidation on chest x ray and revealed to be a soft tissue density mass supplied independently from a systemic artery arising from aorta. Thus CT was essential for diagnosis. Inflammatory lesions:- • Out of 41 patients having inflammatory etiology, majority cases are of only parenchymal involvement 17 cases (41.5%), both parenchymal and pleural pathology 14 cases (34%), only pleural pathology 7 cases (17%), 2 cases of lung involvement with mediastinal node involvement and one case of airway involvement. • Amongst these cases, 3 were in neonatal age group having bilateral diffuse reticulonodular opacity diagnosed as respiratory distress syndrome. 39
  • 40. • In this study, x ray was able to define the various characteristics such as ABG, soft tissue opacity, collapse, and mediastinal shift in 56%, 80%, 35%, and 71 % of patients respectively as compared to CT. • In collapse which was not diagnosed on x ray were mostly resorptive in nature and segmental in distribution. • X ray did not demonstrated mediastinal lymph nodes in 6 pts detected having lymph nodes on CT. • X ray was able to demonstrate cavitary lesions in all 5 patients as their sizes were large. • For detection of pleural fluid, USG as well as CT shown better accuracy than x ray. • Out of 8 pts with pneumothorax, x ray diagnosed in 6 cases (75%) as compared to CT in all patients. • While for characterization of pleural fluid, USG showed presence of echoes and septations in 8 patients. CT was not able to detect echoes and septations in any patient. • X ray showed simultaneous detection of both pulmonary and parenchymal pathology in 50% of patients as compared to CT (7 out of 14 cases). • One case of airway involvement showed bronchiectasis and it showed presence of fluid levels on HRCT. • Thus CT is useful in inflammatory lesions to characterize the lesion, extent of involvement, associated pleural fluid and mediastinal nodal involvement and any associated complication e.g. Brochopleural fistula, pneumatocele formation. Airway involvement:- There were 3 cases of hyperinflation on x ray among which CT was done in two cases and showed presence of soft tissue density foreign body in one case. Another case was diagnosed as ? Obstructive emphysema/?? CLE and was found to be foreign body on bronchoscopy. Another case showed presence of metallic foreign body in bronchus. 40
  • 41. Traumatic lesions:- • One studied case of trauma showed presence of bilateral subcutaneous emphysema on x ray was found to be associated with pneumothorax and Pneumomediastinum on CT. Neoplastic lesions and mediastinal masses:- • Out of 60 patients studied, two cases (3.6%) of neoplasm and 3 mediastinal mass (5%) were found out. • A case of neoplasm presented with opaque hemithorax on x ray showed large necrotic chest wall neoplasm with invasion of pulmonary and mediastinal compartments, diagnosed as PNET. • Mediastinal masses were thymic germ cell tumour, bilateral paravertebral abscess and pericardial cyst. • One case of thymic germ cell tumour showed presence of calcification and fat in the region of thymus and thymus was not seen separately from the lesion. • The pericardial cyst was having partially calcified rim. • Bilateral paravertebral abscess with calcification had same component in epidural region of spinal canal with kyphoscoliosis of spine. Intraspinal extension was better shown on MR examination. Other:- • One case of patient undergoing multiple blood transfusions noted having bilateral diffuse alveolar opacities and was diagnosed as having idiopathic pulmonary hemosiderosis. 41
  • 42. CONCLUSION Various imaging modalities such as X ray, USG, Flouroscopy, CT scan and MRI are available for diagnosis and evaluation of pediatric chest lesions. They have many advantages and disadvantages in common. It is difficult to isolate a single modality with distinct advantage over others. Chest radiography is the first and often only (e.g. for pneumonia) imaging modality used to assess thoracic signs or symptoms providing a survey of lung parenchyma, cardiovascular structures, mediastinum and chest wall structures. Though air being highly reflective, USG is considered invaluable in evaluation of pleural fluid, pleural masses, diaphragmatic lesions and evaluation of thymus as being noninvasive and non radiating. CT is though expensive and having higher radiation dosage, it is quite useful in management of the patient with pediatric chest lesions demonstrating extent of the lesion, particularly in congenital lung malformation. Simultaneous assessment of cross sectional anatomy can be done. With IV contrast, it provides enhancement of vascular structures. CT provides crucial diagnosis in conditions having similar appearance on radiograph e.g. between pneumonia and sequestration, between pneumonia and AV 42
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