Random_19 Flashcards
endemic
vs
epidemic
endemic - found in a certain geographic region or in a specific race of people
epidemic - a disease that is widespread, affecting an “atypically large number of individuals within a population, community, or region at the same time,”
Congenital lobar emphysema.
A, Radiograph obtained at 1 day of age shows diffuse lucency and enlargement
of left upper lobe (arrows). B, CT scan shows hyperlucent and enlarged left upper lobe with asymmetric attenuation of vascular structures and increased space between interstitial septa.
Congenital lobar emphysema
- over-expansion of alveoli
- most common site: LUL
- CXR:
- hyperlucent, hyperexpanded lobe
- initially may appear to be a soft tissue density due to retained fetal lung fluid. It then resolves and is replaced by progressive hyperlucency
- CT:
- air is in the alveoli
- interstitial septa and bronchovascular bundles pushed to the periphery
- air spaces are larger than adjacent normal lung
- pulmonary vessels are attenuated
- Rx: lobectomy
Congenital pulmonary airway malformation / CPAM
Congenital cystic adenomatoid malformation / CCAM
Figure:
Type 1 congenital cystic adenomatoid malformation. A, Coronal fetal MR image shows hyperexpanded, high-signal lesion (arrows) in left lobe. Note lower signal in normal right lung (R). B, Chest radiograph after birth shows lucent, multicystic lesion in left lung with rightward mediastinal shift. C, CT soon after birth shows large, lucent, multicystic lesion in left lung.
Congenital pulmonary airway malformation / CPAM
- majority are detected prenatally
- majority are present with resp distress at birth
- communicate with the bronchial tree at birth and fill with air within the first hours of life
- NO lobar predilection
- vs congenital lobar emphysema (LUL most common)
- 3 types
- Type 1 - >2cm large cysts
- Type 2 - mixed
- Type 3 - <5mm microcysts, solid appearing
- management
- symptomatic - surgical resection
- asymptomatic - controversial. ? risk of infection and malignancy
Pulmonary sequestration
Pulmonary sequestration
- most commonly presents with recurrent pneumonia, usually in late childhood
- do not communicate with the bronchial tree unless they become infected - usually appear as radiopaque mass or resp distress in newborn period
- most common location - LLL
Lobar predilection for:
- CPAM
- congenital lobar emphysema
- pulmonary sequestration
- PVPVR
Lobar predilection for:
- CPAM- NO lobar predilection
- congenital lobar emphysema - LUL
- pulmonary sequestration- LLL
- PVPVR - RUL
Bronchogenic cyst
Bronchogenic cyst
- can occur in the middle mediastinum (most common) or within the lung parenchyma (mainly perihilar in location)
- almost always solitary lesions
- common compress the distal trachea and bronchi
- do NOT contain air until they become infected
- well-defined soft tissue attenuation or cystic masses
Hyperinflation in an infant are much more easily evaluated on the lateral than on the frontal views
Hyperinflation in an infant are much more easily evaluated on the lateral than on the frontal views
Viral lower respiratory infection in a young child.
A, Frontal view shows increased perihilar markings and bandlike density (arrow) in right middle lobe, representing subsegmental atelectasis. B, Lateral view better shows marked hyperinflation with flattened hemidiaphragms, increased anterior-to-posterior diameter of the chest (chest is wider than it is tall), and barrel shape of chest. Increased perihilar markings make hila appear prominent.
Viral pneumonia
- Viral infections affect the airways, causing inflammation of the small airways and peribronchial edema.
- This peribronchial edema appears on radiography as increased peribronchial opacities—symmetric course markings that radiate
from the hila into the lung. - The central portions of the lungs appear to be ‘‘dirty’’ or ‘‘busy.’’ It is one
of the most subjective findings in radiology. - In addition, the combination of the bronchial wall edema, narrowed airway lumen, and necrotic debris and mucus in the airway leads
to small airway occlusion. This results in both hyperinflation and areas of subsegmental atelectasis.
The common causal agents of lower respiratory
tract infections in children vary greatly
with age.
- In all age groups, viral infections are much more common than bacterial infections.
- preschool (4/12 - 5y/o) - 95% viral
- school-age (6y/o - 16y/o) - most still viral; but increased streptococcal pneumonia and mycoplasma pneumonia
*
Bacterial pneumonia.
Radiograph shows focal lung consolidation (P) in lateral aspect of right lower lobe, consistent with bacterial pneumonia.
Bacterial pneumonia
- In contrast to the airway involvement in viral pneumonia, bacterial pneumonia occurs secondary to inhalation of the infectious agent into the air spaces.
- vs. viral pneumonia - affecting airways
- resultant progressive development of inflammatory exudate and edema within the acini, resulting in consolidation of the air spaces.
- air bronchograms
- a propensity for pneumonia to appear ‘‘round’’ in younger children
- more common in children younger than 8 years of age
- most often caused by S. pneumoniae
- related to poor development of pathways of collateral ventilation
- tends to be solitary and occurs more commonly posteriorly and
in the lower lobes - correlate clinically for infectious symptoms, and child should be treated with antibiotics and the chest radiograph repeated. It is best to avoid unnecessary CT examination in this clinical scenario.
- when a round opacity is seen in a child older than 8 years of age, other pathology should be suspected.
Figure:
Round pneumonia. Radiograph shows rounded opacity overlying the left hilum. This is the location of the superior segment of the left lower lobe.
Ultrasound may play a more useful role than CT in the early evaluation of parapneumonic effusions. It is not uncommon for ultrasound to show multiple septations and in the same case to show no evidence of septations on CT. We currently advocate ultrasound, rather than CT or decubitus radiographs, in the primary evaluation of parapneumonic effusions.
Figure:
Parapneumonic effusion (empyema) evaluated by CT and ultrasound. A, CT shows left parapneumonic effusion. There are no findings to suggest empyema on CT. There are no septations seen by CT, which is typical. B, Ultrasound shows consolidated lung (L) with surrounding band of pleural fluid (arrows). Note multiple echogenic septations consistent with complex effusion.
Ultrasound may play a more useful role than CT in the early evaluation of parapneumonic effusions. It is not uncommon for ultrasound to show multiple septations and in the same case to show no evidence of septations on CT. We currently advocate ultrasound, rather than CT or decubitus radiographs, in the primary evaluation of parapneumonic effusions.
Cavitary necrosis with bronchopulmonary fistula
formation.
CTshows consolidation of the right lung. Portions of the lung demonstrate cavitary necrosis (arrows). There are also areas of consolidated lung that enhance (L) and are not compromised. There is a pleural effusion (P) that contains both air and fluid. There is thickening and enhancement of the parietal pleura (white arrowhead) and thickening of the extrapleural space (black arrowhead), both findings that claimed to be suggestive of empyema rather than transudative effusion but were shown to be inaccurate.
Most common sequelae of acute pneumonia in children
Figure:
Chronic complications related to recurrent pneumonias. CT shows multiple round, soft tissue density lesions in medial right lower lobe (arrows) consistent with bronchiectasis with mucus plugging. In the left lower lobe, there is an area of air trapping (arrowheads) consistent with obliterative bronchiolitis. This area remained hyperlucent on expiratory images.
Most common sequelae of acute pneumonia in children
- bronchiectasis
- Swyer-James syndrome
- virus-induced necrotizing bronchiolitis
- oblieterative bronchiolitis
- hyperlucent and enlarged lung with air trapping; less prominent pulmonary vasculature
when lung consolidation is seen with associated lymphadenopathy or effusion in a child who is not acutely ill, there should be a high suspicion for tuberculosis. Most of the cases of pulmonary tuberculosis that I have seen have demonstrated unilateral hilar lymphadenopathy.
when lung consolidation is seen with associated lymphadenopathy or effusion in a child who is not acutely ill, there should be a high suspicion for tuberculosis. Most of the cases of pulmonary tuberculosis that I have seen have demonstrated unilateral hilar lymphadenopathy.
Tuberculosis in a 7-year-old boy.
A and B, Frontal and lateral radiographs of the chest demonstrate a left hilar mass (arrows) consistent with unilateral lymphadenopathy. There is also left upper lobe collapse. Note displaced major fissure on lateral view (arrowheads).
Fungal infection
Figure:
Fungal pneumonia in child after bone marrow transplantation for aplastic anemia. A, CT shows poorly defined nodules and associated ground-glass opacity. B, A CT taken earlier shows clear lungs. Note the striking change since this baseline study.
Fungal infection
The hallmark CT finding indicating fungal infection is the presence of nodules.
They are commonly clustered and may exhibit poorly defined margins, cavitation, or a surrounding halo that has the opacity of ground glass.
Figure:
Histoplasmosis infection. CT shows multiple nodules bilaterally. There is a biopsy site on the left, anteriorly.
Acute chest syndrome in a 6-year-old boy with
sickle cell anemia.
A, Chest radiograph obtained at admission shows low lung volumes and minimal focal opacity within the left lower lobe. B, Chest radiograph obtained 1 day later shows consolidation of a large portion of the left lung. C, Chest radiograph obtained 2 days after A shows complete left lung opacification.
Although it is debated whether the cause of such episodes is more often related to infection or infarction, many believe the lung opacities are related to rib infarction, splinting, and subsequent areas of atelectasis.
Radiography often shows segmental to lobar pulmonary opacities but can also be normal. There can be an associated increase in cardiomegaly. Bone scans may show rib infarcts.
Cystic fibrosis.
A, Radiograph shows areas of bronchial wall thickening and bronchiectasis, most prominent in the right upper lobe. B, High-resolution CT shows diffuse bronchiectasis and bronchial wall thickening within the upper lobes. There are also multiple areas of poorly defined opacities, particularly in the peripheral portions of the left upper lobe. These have a tree-in-bud appearance.
Cystic fibrosis
Imaging findings:
hyperinflation, increased peribronchial markings, mucus plugging, and bronchiectasis.
The hilar areas can become prominent because of a combination of lymphadenopathy secondary to the chronic inflammation and enlarged central pulmonary arteries related to the development of pulmonary arterial hypertension.
Lung contusion and laceration after a motor vehicle
accident.
CT shows characteristic findings of contusion on the left, including posterior location, crescent shape, nonsegmental distribution, and subpleural sparing (arrows). On the right, there is large pneumothorax (PTX) and consolidation of lung with an air-filled cyst (arrow) consistent with lung laceration.
Thymic cysts
vs
Thymic enlargement and calcifications
- Thymic cysts - associated with AIDS
- Thymic enlargement and calcificatins - associated with Langerhan cell histiocytosis
Figure:
Enlarged thymus with calcifications in child with Langerhans cell histiocytosis. CT shows prominent thymus with high-attenuation calcifications.
Pediatric thymus
“Sail sign” vs “Spinnaker sail sign”
Figure:
Normal, prominent thymus with ‘‘sail’’ sign. Radiograph shows prominent but normal thymus with rightward triangular extension (arrow).
Figure:
‘‘Spinnaker sail sign’’ in child with pneumomediastinum. Radiograph shows thymus (arrows) lifted off of mediastinum by air in mediastinum. The uplifted thymus resembles a spinnaker sail.
Lymphoma.
A, Frontal radiograph shows marked enlargement of superior mediastinum and associated right pleural effusion. B, Lateral radiograph shows posterior displacement, compression, and poor visualization of the trachea (arrow), further supporting the presence of an abnormal mediastinal mass. C, CT shows large anterior mediastinal mass (M) with compression and posterior displacement of trachea (arrow) and compression of the superior vena cava (arrowhead). Note right pleural effusion. D, Coronal CT again shows mass (M) and compression of superior vena cava (arrow).
NOTE: normal thymus will NOT cause mass effect on the adjacent structures!!
Lymphoma with pericardial effusion.
CT image from level of heart in a child with an anterior mediastinal mass; on more superior images shows extension of lymphoma mass (L) inferiorly. Note adjacent pericardial fluid (arrowheads) and bilateral pleural fluid (arrows).
Teratoma.
CT shows anterior mediastinal mass (M) that is of fat attenuation.
Neuroblastoma.
A, Radiograph shows a large mass in right upper hemithorax. There is widening (W) of the interspace between the right third and fourth ribs and erosion of the undersurface of the right third rib (arrow). The rib splaying and erosion document chest wall involvement and the posterior nature of the tumor. B, CT shows large mass (M) with compression of the trachea (arrow). The mass is so large it extends from anterior to posterior chest walls. C, MIBG scan shows avid uptake of radiotracer within the mass (arrows), consistent with a neurogenic tumor. D, Photograph taken during surgical resection shows a mass (M) arising
from the posterior chest.
the working diagnosis for posterior
mediastinal masses in young children is neuroblastoma
until proven otherwise.
the working diagnosis for posterior
mediastinal masses in young children is neuroblastoma
until proven otherwise.
Askin tumor
(primitive neuroectodermal tumor of the chest wall)
Askin tumor
(primitive neuroectodermal tumor of the chest wall)
Haller index, which quantifies the severity of the pectus deformity.
To calculate the Haller index, low tube current (mA) images are obtained through the level of the greatest degree of pectus deformity.
The Haller index is equal to the transverse left-to-right diameter of the chest, divided by the anterior-to-posterior diameter. The greater the Haller index, the
more severe the pectus.
A patient with a Haller index greater than 3.2 is considered a surgical
candidate.
Approach to CXR in congenital heart disease
Approach to CXR in congenital heart disease
- pulmonary vascularity
- normal
- increased arterial flow
- distinct and well-defined borders
- right interlobar artery larger than the trachea
- increased venous flow
- indistinct and poorly-defined borders
- congestive heart failure and pulmonary edema
- decreased arterial flow
- cardiac size
- on lateral view, if the posterior heart border extends over the vertebral bodies –> cardiomegaly
- cardiac axis - configuration of the apex
- if apex orientated superiorly - right side enlargement
- if apex oriented inferiorly - left side enlargement
- situs
- situs solitus - normal configuration
- situs inversus - mirror image of normal configuration; 3-5% associated CHD
- situs ambiguous
- asplenia - bilateral right-sidedness - associated complex, cyanotic CHD; susceptible to infections due to the lack of a spleen; malrotation; microgastria; midline gallbladder; bilateral right sided bronchi; decreased pulmonary arterial flow; azygous continuation of IVC
- polysplenia - bilateral left-sidedness - less complex, acyanotic heart disease (usually L-to-R shunts); azygous continuation of IVC; bilateral SVC; malrotation; midline liver; absent gallbladder.
- position of aortic arch
Right aortic arch
and
Truncus ateriosus
A right aortic arch is present in one third of patients. The identification
of a right aortic arch in the presence of increased pulmonary arterial flow in a cyanotic child is highly suggestive of truncus arteriosus.
Figure:
Truncus arteriosus. Chest radiograph shows increased pulmonary arterial flow, cardiomegaly, and rightsided aortic arch (arrows). Note the indentation on the right wall of the trachea and the straight course of the trachea from superior to inferior, secondary to the right aortic arch.
TAPVR can be divided into supracardiac, cardiac, or infracardiac
subtypes.
- Supracardiac is the most common form; in this form the pulmonary veins converge and form a left vertical vein that runs superiorly and connects into the innominate vein.
- With infracardiac TAPVR, the returning veins penetrate the diaphragm and connect to the IVC below the level of diaphragm.
- These veins may become obstructed, and the patient may present with a pulmonary edema pattern on chest radiography
- If the veins are not obstructed, the lesion may
appear with cardiomegaly and increased pulmonary
arterial flow, similar to other left-to-right
shunts
Figure:
Total anomalous pulmonary venous return, infracardiac type, with venous obstruction in a newborn. Chest radiograph demonstrates diffuse pulmonary opacity with indistinctness of the pulmonary vascularity.
Supracardiac TAPVR classically demonstrates a ‘‘snowman’’ appearance,
in which the dilated left vertical vein and dilated SVC form the superior portion of the snowman, and the cardiac silhouette forms the inferior portion.
Figure:
Total anomalous pulmonary venous return, infracardiac type, without venous obstruction in a newborn. The appearance is typical of a left-to-right shunt. A, Frontal chest radiograph shows mild prominence of cardiac silhouette and increased pulmonary arterial flow. B, Lateral chest radiograph shows cardiomegaly and hyperinflated lungs, which are commonly seen in left-to-right shunts.
Total anomalous pulmonary venous return, supracardiac type in an older child.
A, Chest radiograph shows ‘‘snowman’’ appearance of mediastinum. There is enlargement of the superior mediastinum (arrows) secondary to dilatated left vertical vein and SVC. There is also increased pulmonary arterial flow. B, MRI coronal gradient echo bright-blood image shows vertical vein (VV) draining into superior vena cava (SVC). C, Venogram with catheter in pulmonary vein shows left (LPV) and right (RPV) pulmonary veins draining into vertical vein (VV). D, Later image from venogram shows contrast draining from vertical vein (VV) into superior vena cava (SVC).
D-TGA is the most common congenital heart disease presenting with cyanosis during the first 24 hours of life.
The most common chest radiographic appearance of a newborn
child with D-TGA is normal. Classically described radiographic findings include narrowing of the superior mediastinum due to decreased thymic tissue and abnormal relationships of the great vessels and to increased pulmonary arterial flow, as previously mentioned. The appearance of the mediastinum has been likened to that of an egg on a string.
D-transposition of the great arteries (D-TGA) in a newborn male with a chest radiograph that appears to be relatively normal. Chest radiograph shows normal pulmonary vascularity. The classically described findings of D-TGA, such as increased pulmonary arterial flow and an egg-on-a-string appearance of the mediastinum, are absent.
Perhaps a more practical way of predicting which type of shunt is present is by determining the age at presentation.
- Patients with very large shunts, such as VSDs or atrioventricular canals, present in infancy.
- ASDs typically present later in childhood or in early adulthood.
- PDAs occur most commonly in premature infants.
- Atrioventricular canals occur commonly in patients with Down syndrome.
On chest radiography, neonates with left-toright shunts demonstrate increased pulmonary arterial flow, a variable amount of associated
increased pulmonary venous flow (pulmonary edema), and cardiomegaly.
It is common for infants with large left-to-right shunts also to have marked hyperinflation on chest radiography. This is thought to be secondary to air trapping due to the peribronchial edema.
Cor triatriatum
Cor traitriatum
Presence of a membrane dividing the left atrium into two separate chambers. The membrane has a pinlike hole centrally that is the only route for forward blood flow and causes relative obstruction.
Due to abnormal incorporation of pulmonary veins into the LA with an uncessary fibromuscular membranous subdivision through the LA.
DDx for CHF in newborn
- anatomic causes
- systemic causes
Coarctation of the aorta associated with congestive heart failure in a newborn. A, Chest radiograph shows cardiomegaly and increased and indistinct pulmonary vasculature. B, CT arteriography shows coarctation (arrows) as narrowing of the aorta in a juxtaductal location.
Hypoplastic left heart with associated congestive heart
failure in a newborn. Radiograph shows cardiomegaly and indistinct
pulmonary vasculature. Note that patients with hypoplastic left
heart do not necessarily have hearts that appear to be small.
Aortic stenosis with poststenotic dilatation. A, Radiography shows visualization and prominence of the shadow of the ascending aorta (arrows). Normally, the shadow of the ascending aorta is not seen in children. B, Aortogram shows markedly enlarged ascending aorta (A).
C, CT shows marked enlargement of the ascending aorta (A) as compared to the descending aorta (D).
Pulmonic stenosis in a 7-year-old girl. Radiograph shows slight prominence of the main pulmonary artery (arrow).