Pediatric Chest X Ray Dr Hussein Abass 2023.pptx

for all health workers

1. Pediatric Chest X-Ray Dr Hussein Abass Consultant of Pediatrics Egypt 2023

2. Do not forget to interpret CXR in Conjunction with the Clinical Findings

3. Wilhelm Conrad Röntgen (27 March 1845 – 10 February 1923) was a German mechanical engineer and physicist, who, on 8 November 1895, produced and detected electromagnetic radiation in a wavelength range known as X-rays or Röntgen rays , an achievement that earned him the inaugural Nobel Prize in Physics in 1901 .In honour of Röntgen's accomplishments, in 2004 the International Union of Pure and Applied Chemistry (IUPAC) named element 111, Roentgenium , a radioactive element with multiple unstable isotopes, after him. The unit of measurement Roentgen was also named after him.

4. X-rays X-rays are a form of electromagnetic radiation. They belong to the short-wavelength , high-frequency end of the electromagnetic spectrum, between the gamma and the ultraviolet radiation. They have wavelengths in the range of to (10nm – 0.01nm). Their frequency range is 3x Hz to 3x Hz. X-Ray Range X-rays can be produced in several ways: by the movement of electrons in atoms or by transformation of kinetic energy to Bremsstrahlung radiation. It is when particles with high energy (ex: electrons, protons or heavier ions) or photons hit the surface of a solid material (ex: metal) that x-rays are produced. When a photon collides with another atom, the atom may absorb the photon’s energy causing an electron to jump to a higher energy level. This can only happen if the energy level of the photon matches the energy difference between the two electron levels. The electron then falls back to its original energy level, releasing the extra energy in the form of a light photon. When the fast electrons, protons or heavier ions collide with the atoms of the solid material, they slow down or completely stop. This is when their kinetic energy is transformed to Bremsstrahlung radiation. Bremsstrahlung has a wide rage of X-ray wavelengths and in the spectrum you can also find characteristic X-rays that are associated with the atoms of the material that is used. The soft tissue in our body is composed of atoms that do not absorb X-ray photons very well, because their energy levels do not match the energy of the photons. However, the bone tissue absorbs these same photons quite well, due to the calcium atoms that have higher energy levels between its atoms that match the photons' energy. In air filled organs there is hardly any absorption (because of the air) and the photons easily just pass through, hence the clear boundaries.  

5. X-rays can be generated by an X-ray tube, a vacuum tube that uses a high voltage to accelerate the electrons released by a hot cathode to a high velocity. The high velocity electrons collide with a metal target, the anode, creating the X- rays.In medical X-ray tubes the target is usually tungsten or a more crack-resistant alloy of rhenium (5%) and tungsten (95%), but sometimes molybdenum for more specialized applications, such as when softer X-rays are needed as in mammography. In crystallography, a copper target is most common, with cobalt often being used when fluorescence from iron content in the sample might otherwise present a problem. The maximum energy of the produced X-ray photon is limited by the energy of the incident electron, which is equal to the voltage on the tube times the electron charge, so an 80 kV tube cannot create X-rays with an energy greater than 80 keV. When the electrons hit the target, X-rays are created by two different atomic processes: Characteristic X-ray emission (X-ray electroluminescence): If the electron has enough energy, it can knock an orbital electron out of the inner electron shell of the target atom. After that, electrons from higher energy levels fill the vacancies, and X-ray photons are emitted. This process produces an emission spectrum of X-rays at a few discrete frequencies, sometimes referred to as spectral lines. Usually, these are transitions from the upper shells to the K shell (called K lines), to the L shell (called L lines) and so on. If the transition is from 2p to 1s, it is called Kα, while if it is from 3p to 1s it is Kβ. The frequencies of these lines depend on the material of the target and are therefore called characteristic lines. The Kα line usually has greater intensity than the Kβ one and is more desirable in diffraction experiments. Thus the Kβ line is filtered out by a filter. The filter is usually made of a metal having one proton less than the anode material (e.g. Ni filter for Cu anode or Nb filter for Mo anode).

6. Bremsstrahlung : This is radiation given off by the electrons as they are scattered by the strong electric field near the high-Z (proton number) nuclei. These X-rays have a continuous spectrum. The frequency of Bremsstrahlung is limited by the energy of incident electrons. So, the resulting output of a tube consists of a continuous Bremsstrahlung spectrum falling off to zero at the tube voltage, plus several spikes at the characteristic lines. The voltages used in diagnostic X-ray tubes range from roughly 20 kV to 150 kV and thus the highest energies of the X-ray photons range from roughly 20 keV to 150 keV. Both of these X-ray production processes are inefficient, with only about one percent of the electrical energy used by the tube converted into X-rays, and thus most of the electric power consumed by the tube is released as waste heat. When producing a usable flux of X-rays, the X-ray tube must be designed to dissipate the excess heat. A specialized source of X-rays which is becoming widely used in research is synchrotron radiation, which is generated by particle accelerators. Its unique features are X-ray outputs many orders of magnitude greater than those of X-ray tubes, wide X-ray spectra, excellent collimation, and linear polarization. Short nanosecond bursts of X-rays peaking at 15 keV in energy may be reliably produced by peeling pressure-sensitive adhesive tape from its backing in a moderate vacuum. This is likely to be the result of recombination of electrical charges produced by triboelectric charging. The intensity of X-ray triboluminescence is sufficient for it to be used as a source for X-ray imaging.

7. Types of X-rays There are two types of X-rays, according to their photon energy. The photon energy is given by the formula E = hν where E is the energy in Joules , h is Planck's constant and ν is the frequency of the photon . The frequency of the photon (ν) can also be obtained from the equation c = λν where c is the speed of light (~3.0 * 108 m/s) and λ is the photon's wavelength. Because Planck's constant is small ( ~6.62 * 10-34 Joule-seconds), it is typically more convenient to work in electron-Volts (eV) where one eV is about 1.602 * 10-19 Joule. For example, visible light photons with wavelengths between 700nm and 400nm have energies between 1.77 eV and 3.1 eV respectively. Soft X-rays These x-rays are defined by having photon energies below 10keV . They have less energy than the hard x-rays, therefore they have longer wavelength . Soft X-rays are used in radiography to take pictures of bones and internal organs. Because of their lower energy, they do not cause much damage to tissues, unless they are repeated too often. Hard X-rays Hard X-rays have photon energies above 10 keV . They have shorter wavelength than the soft x-rays. These X-rays are used in radiotherapy , a treatment for cancer. Due to their higher energy , they destroy molecules within specific cells, thus destroying tissue. Another use for these X-rays is in airport security scanners to examine baggage. keV = kilo electron volt = 1000 electron volts Kilovolt (kV) or kilo electron volt (keV means the energy equal to that acquired by a particle with one electron charge in passing through a potential difference of one thousand volts in a vacuum. Current convention is to use kV for photons and keV for electrons.

8. Production of X-rays The X-rays were discovered in 8th November in 1895 when Wilhelm Conrad Rontgen was working with a cathode ray tube in his laboratory. X-rays for medical diagnostic procedures are produced in a X-ray tube. X-ray tube The tube itself is evacuated, and contains two electrodes: -Cathode: the heated filament acts as the cathode (negative) from which electrons are emitted -Anode: the anode (positive) is made of a heavy metal, usually tungsten. An external power supply produces a voltage of up to 200 kV between the two electrodes. This accelerates the electrons across the gap between the cathode and the anode. The kinetic energy of an electron arriving at the anode is around 200 kV. When the electrons strike the anode at high speed, parts of their kinetic energy is transformed into X-ray photons that emerge in all directions. Only a small fraction of kinetic energy of electrons are converted into x-rays. The rest of the energy is transfered to the anode as thermal energy. Some X-ray tubes have water circulating through the anode to remove this surplus of heat. The X-rays that emerge from the x-ray tube have a range of energies, represented in a X-ray spectrum. This spectrum have two components: the Brehmsstrahlung radiation and the characteristic X-rays. These arise from different ways is related to the way which an individual electron loses it's energy when crashes into the anode. When the electron striking into anode loses its energy and interacts with the electric fields of the anode nucleus this may result in a single X-ray photon or several photons. These all contribute to Brehmsstrahlung radiation. An electron may cause a rearrangement of the electrons in the anode atom in which an electron drops from a high energy level to a lower energy level. As it does so, it emits a photon with a defined frequency. This contributes to the characteristic X-rays that are characteristic of the anode (if the anode is made of copper instead of tungsten the characteristic X-rays will be different).

9. Rolf Maximilian Sievert (6 May 1896 – 3 October 1966) was a Swedish medical physicist whose major contribution was in the study of the biological effects of ionizing radiation. The sievert ( Sv ) , the SI unit representing the stochastic health risk of ionizing radiation, is named for him. He has been called the " Father of Radiation Protection ".

10. The sievert = Sv is a unit in the International System of Units (SI) intended to represent the stochastic health risk of ionizing radiation, which is defined as the probability of causing radiation-induced cancer and genetic damage. The sievert is important in dosimetry and radiation protection. It is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dose measurement and research into the biological effects of radiation. The sievert is used for radiation dose quantities such as equivalent dose and effective dose, which represent the risk of external radiation from sources outside the body, and committed dose, which represents the risk of internal irradiation due to inhaled or ingested radioactive substances. According to the International Commission on Radiological Protection (ICRP) one sievert results in a 5.5% probability of eventually developing fatal cancer based on the disputed linear no-threshold model of ionizing radiation exposure. To calculate the value of stochastic health risk in sieverts, the physical quantity absorbed dose is converted into equivalent dose and effective dose by applying factors for radiation type and biological context, published by the ICRP and the International Commission on Radiation Units and Measurements (ICRU). One sievert equals 100 rem, which is an older, CGS radiation unit. Conventionally, deterministic health effects due to acute tissue damage that is certain to happen, produced by high dose rates of radiation, are compared to the physical quantity absorbed dose measured by the unit gray ( Gy ).

11. The sievert is named after Rolf Maximilian Sievert. As with every SI unit named for a person, its symbol starts with an upper case letter ( Sv ), but when written in full it follows the rules for capitalisation of a common noun; i.e., "sievert" becomes capitalised at the beginning of a sentence and in titles, but is otherwise in lower case. Frequently used SI prefixes are the millisievert (1 mSv = 0.001 Sv ) and microsievert (1 μSv = 0.000 001 Sv ) and commonly used units for time derivative or "dose rate" indications on instruments and warnings for radiological protection are μSv /h and mSv/h. Regulatory limits and chronic doses are often given in units of mSv/a or Sv /a, where they are understood to represent an average over the entire year. In many occupational scenarios, the hourly dose rate might fluctuate to levels thousands of times higher for a brief period of time, without infringing on the annual limits. The conversion from hours to years varies because of leap years and exposure schedules, but approximate conversions are: 1 mSv/h = 8.766 Sv /a 114.1 μSv /h = 1 Sv /a Conversion from hourly rates to annual rates is further complicated by seasonal fluctuations in natural radiation, decay of artificial sources, and intermittent proximity between humans and sources. The ICRP once adopted fixed conversion for occupational exposure, although these have not appeared in recent documents: 8 h = 1 day 40 h = 1 week 50 weeks = 1 year Therefore, for occupation exposures of that time period, 1 mSv/h = 2 Sv /a 500 μSv /h = 1 Sv /a

12. rem Like all methods of radiography, chest radiography employs ionizing radiation in the form of X-rays to generate images of the chest. The mean radiation dose to an adult from a chest radiograph is around 0.02 mSv (2 mrem)= millirem roentgen equivalent man (rem) for a front view (PA, or posteroanterior) and 0.08 mSv (8 mrem) for a side view (LL, or latero-lateral). Together, this corresponds to a background radiation equivalent time of about 10 days. The roentgen equivalent man (rem) is a CGS unit of equivalent dose, effective dose, and committed dose, which are dose measures used to estimate potential health effects of low levels of ionizing radiation on the human body. Quantities measured in rem are designed to represent the stochastic biological risk of ionizing radiation, which is primarily radiation-induced cancer. These quantities are derived from absorbed dose, which in the CGS system has the unit rad. There is no universally applicable conversion constant from rad to rem; the conversion depends on relative biological effectiveness (RBE). The rem has been defined since 1976 as equal to 0.01 sievert, which is the more commonly used SI unit outside the United States. Earlier definitions going back to 1945 were derived from the roentgen unit, which was named after Wilhelm Röntgen , a German scientist who discovered X-rays. The unit name is misleading, since 1 roentgen actually deposits about 0.96 rem in soft biological tissue, when all weighting factors equal unity. Older units of rem following other definitions are up to 17% smaller than the modern rem. Doses greater than 100 rem received over a short time period are likely to cause acute radiation syndrome (ARS), possibly leading to death within weeks if left untreated. Note that the quantities that are measured in rem were not designed to be correlated to ARS symptoms. The absorbed dose, measured in rad, is a better indicator of ARS. A rem is a large dose of radiation, so the millirem (mrem), which is one thousandth of a rem, is often used for the dosages commonly encountered, such as the amount of radiation received from medical x-rays and background sources.

13. Usage The rem and millirem are CGS units in widest use among the U.S. public, industry, and government. However, the SI unit the sievert ( Sv ) is the normal unit outside the United States, and is increasingly encountered within the US in academic, scientific, and engineering environments. The conventional units for dose rate is mrem/h. Regulatory limits and chronic doses are often given in units of mrem/ yr or rem/ yr , where they are understood to represent the total amount of radiation allowed (or received) over the entire year. In many occupational scenarios, the hourly dose rate might fluctuate to levels thousands of times higher for a brief period of time, without infringing on the annual total exposure limits. There is no exact conversion from hours to years because of leap years, but approximate conversions are: 1 mrem/h = 8,766 mrem/ yr 0.1141 mrem/h = 1,000 mrem/ yr The International Commission on Radiological Protection (ICRP) once adopted fixed conversion for occupational exposure, although these have not appeared in recent documents: 8 h = 1 day 40 h = 1 week 50 week = 1 yr Therefore, for occupation exposures of that time period, 1 mrem/h = 2,000 mrem/ yr 0.5 mrem/h = 1,000 mrem/ yr The U.S. National Institute of Standards and Technology (NIST) strongly discourages Americans from expressing doses in rem, in favor of recommending the SI unit.The NIST recommends defining the rem in relation to the SI in every document where this unit is used.

14. The dose of radiation received from diagnostic X-ray procedures is quite small (go here) and the risk of this causing a fatal cancer or causing genetic problems is quite small. For every total body rad (or 1cGy or 1000mRem or 1Rem or 10mSv) the odds of dying of cancer go up only by 1/2500 (0.04%) which is quite small when you consider every one already has a 23% risk of dying of cancer and about a 40% risk of developing cancer . The risk of severe genetic defects in first generation offspring due to occupational radiation exposure to one or both parents is estimated to be 4 in 1,000,000 (0.0004%) per mSv. Under NRC guidelines (go here) the limit exposure dose for occupational workers is 5 rem/ year (50mSv) and the general public 0.5 rem (5mSv). (For comparison, the exposure from a total body CT scan is 12mSv and the dose to Japanese atomic bomb survivors was 20mSv.) Background radiation everyone is exposed to is about 3.6mSv or 360mRem/year .For another discussion of the health risks of CT scan go here and here. A recent review of risks from medical imaging here. There is web site calculator that will calculate the cancer risk from diagnostic imaging here, using data here, here ,here, here, here, here and here PET scanning is non-invasive, but it does involve exposure to ionizing radiation. The total dose of radiation is small, however, usually around 11 mSv. This can be compared to 2.2 mSv average annual background radiation in the UK, 0.02 mSv for a chest x-ray, up to 20 mSv for a CT scan of the chest. A policy change suggested by the IFALPA member associations in year 1999 mentioned that an aircrew member is likely to receive a radiation dose of 4–9 mSv per year. the units of radiation dose are: Gray ( Gy ) is the SI unit of absorbed dose. One gray is equal to an absorbed dose of 1 Joule/kilogram (100 rads). Rad is the special unit of absorbed dose. One rad is equal to an absorbed dose of 100 ergs/gram or 0.01 joule/kilogram (0.01 gray).Rem is the special unit of any of the quantities expressed as dose equivalent. The dose equivalent in rems is equal to the absorbed dose in rads multiplied by the quality factor (1 rem=0.01 sievert). Sievert is the SI unit of any of the quantities expressed as dose equivalent. The dose equivalent in sieverts is equal to the absorbed dose in grays multiplied by the quality factor (1 Sv =100 rems). So basically 1 rad = 1 rem = 1cGy = 10mSv or 100 rad = 100 rem = 1Gy = 1Sv . The radiation risks to a pregnant woman cause considerable concern. There is general agreement that fetal exposure of less than 5 rads is not considered teratogenic. It cannot be stated that there are no risks associated with lower doses, however.

15. Lead shielding Lead shielding refers to the use of lead as a form of radiation protection to shield people or objects from radiation so as to reduce the effective dose. Lead can effectively attenuate certain kinds of radiation because of its high density and high atomic number; principally, it is effective at stopping gamma rays and x-rays. Operation Lead's high density is caused by the combination of its high atomic number and the relatively short bond lengths and atomic radius. The high atomic number means that more electrons are needed to maintain a neutral charge and the short bond length and a small atomic radius means that many atoms can be packed into a particular lead structure. Because of lead's density and large number of electrons, it is well suited to scattering x-rays and gamma-rays. These rays form photons, a type of boson, which impart energy onto electrons when they come into contact. Without a lead shield, the electrons within a person's body would be affected, which could damage their DNA. When the radiation attempts to pass through lead, its electrons absorb and scatter the energy. Eventually though, the lead will degrade from the energy to which it is exposed. However, lead is not effective against all types of radiation. High energy electrons (including beta radiation) incident on lead may create bremsstrahlung radiation, which is potentially more dangerous to tissue than the original radiation. Furthermore, lead is not a particularly effective absorber of neutron radiation.

16. Types Lead is used for shielding in x-ray machines, nuclear power plants, labs, medical facilities, military equipment, and other places where radiation may be encountered. There is great variety in the types of shielding available both to protect people and to shield equipment and experiments. In gamma-spectroscopy for example, lead castles are constructed to shield the probe from environmental radiation. Personal shielding includes lead aprons (such as the familiar garment used during dental x-rays), thyroid shields, and lead gloves. There are also a variety of shielding devices available for laboratory equipment, including lead castles, structures composed of lead bricks, and lead pigs, made of solid lead or lead-lined containers for storing and transporting radioactive samples. In many facilities where radiation is produced, regulations require construction with lead-lined plywood or drywall to protect adjoining rooms from scatter radiation. Wear A lead apron or leaded apron is a type of protective clothing that acts as a radiation shield. It is constructed of a thin rubber exterior and an interior of lead in the shape of a hospital apron. The purpose of the lead apron is to reduce exposure of a hospital patient to x-rays to vital organs that are potentially exposed to ionizing radiation during medical imaging that uses x-rays (radiography, fluoroscopy, computed tomography). Protection of the reproductive organs with a lead rubber apron is considered important because DNA changes to sperm or egg cells of the patient may pass on genetic defects to the offspring of the patient, causing serious and unnecessary hardship for child and parents. The thyroid gland is especially vulnerable to x-ray exposure. Care should be taken to place a lead apron over the thyroid gland before taking dental radiographs.Aprons used for dental imaging should include thyroid collars. However, in poorer or loosely regulated countries, possibly due to the cost of such equipment (approx. 40 USD), no such lead protection is given to the patients themselves, though the operators do get out of the x-ray room for their own safety. The correct thickness of lead-equivalent ( Pbeq ) wear will depend on how long and how often the person is working in an exposed environment. The minimum requirement is to wear 0.25 mm Pbeq when not behind lead shielding. In a theatre using fluoroscopy (e.g. orthopaedics , cardiology or interventional radiology) 0.35 or 0.5 mm lead may be appropriate because of the higher KV employed, and on proximity to the primary beam.

17. Lead shielding

18. Types of imaging Classic imaging In this method, instead of a shield, an X-ray film is used, on which a latent image is formed after exposure to radiation. This image is a two-dimensional recording of a three-dimensional object. Foil films with photographic emulsion are most often used, which are placed between reinforcing foils. X- ray radiation falling on this film induces fluorescenceand significantly enhances the effect of radiation on the film. The film is then developed using the same procedure as in photographic practice. The resulting image is a negative on which the structures of the body are manifested by highlighting and shading. Structures absorbing more radiation create brighter areas, structures absorbing less radiation create darker areas (thanks to the negative). The evaluation of images is most often done using a negatoscope - a medical device that emits homogeneous intense light. Digital imaging A more modern method where images are obtained in digital form. This is done in several ways: 1- Computed radiography - the use of phosphor foils, which are placed in similar cassettes as X-ray films. The image is obtained by scanning the cassettes with a laser point by point, and is thus transferred to the computer. 2- Direct radiography – radiation is captured by a matrix of detectors, where it is converted directly into an electrical signal. The advantage of this method is the high quality of the images, the possibility of editing the image on the computer (brightness, contrast, etc.), archiving the images in digital form and easy distribution around the hospital or outside it. Last but not least, lower economic costs. The disadvantage is the higher purchase price of the equipment.

19. Radiography = a single image is recorded for later evaluation. Mammography is a special type of radiography to image the internal structures of breasts. Fluoroscopy = a continuous X-ray image is displayed on a monitor, allowing for real-time monitoring of a procedure or passage of a contrast agent ("dye") through the body. Fluoroscopy can result in relatively high radiation doses, especially for complex interventional procedures (such as placing stents or other devices inside the body) which require fluoroscopy be administered for a long period of time. CT = many X-ray images are recorded as the detector moves around the patient's body. A computer reconstructs all the individual images into cross-sectional images or "slices" of internal organs and tissues. A CT exam involves a higher radiation dose than conventional radiography because the CT image is reconstructed from many individual X-ray projections.

20. Health effects of X-Ray Ionizing radiation has deterministic and stochastic effects on human health. The deterministic effects that can lead to acute radiation syndrome only occur in the case of high doses (> ~10 rad or > 0.1 Gy ) and high dose rates (> ~10 rad/h or > 0.1 Gy /h). A model of deterministic risk would require different weighting factors (not yet established) than are used in the calculation of equivalent and effective dose. To avoid confusion, deterministic effects are normally compared to absorbed dose in units of rad, not rem. Stochastic effects are those that occur randomly, such as radiation-induced cancer. The consensus of the nuclear industry, nuclear regulators, and governments, is that the incidence of cancers caused by ionizing radiation can be modeled as increasing linearly with effective dose at a rate of 0.055% per rem (5.5%/ Sv ). Individual studies, alternate models, and earlier versions of the industry consensus have produced other risk estimates scattered around this consensus model. There is general agreement that the risk is much higher for infants and fetuses than adults, higher for the middle-aged than for seniors, and higher for women than for men, though there is no quantitative consensus about this.There is much less data, and much more controversy, regarding the possibility of cardiac and teratogenic effects, and the modelling of internal dose. The ICRP recommends limiting artificial irradiation of the public to an average of 100 mrem (1 mSv) of effective dose per year, not including medical and occupational exposures. For comparison, radiation levels inside the United States Capitol are 85 mrem/ yr (0.85 mSv/ yr ), close to the regulatory limit, because of the uranium content of the granite structure.

21. X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds. This makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a short period of time causes radiation sickness, while lower doses can give an increased risk of radiation-induced cancer. In medical imaging, this increased cancer risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in cancer treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy. Hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects. The most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry (e.g. industrial radiography and industrial CT scanning) and research (e.g. small animal CT). The penetration depth varies with several orders of magnitude over the X-ray spectrum. This allows the photon energy to be adjusted for the application so as to give sufficient transmission through the object and at the same time provide good contrast in the image. X-rays have much shorter wavelengths than visible light, which makes it possible to probe structures much smaller than can be seen using a normal microscope. This property is used in X-ray microscopy to acquire high-resolution images, and also in X-ray crystallography to determine the positions of atoms in crystals.

22. Risks of X-Ray As in many aspects of medicine, there are risks associated with the use of X-ray imaging, which uses ionizing radiation to generate images of the body. Ionizing radiation is a form of radiation that has enough energy to potentially cause Damage to DNA . Risks from exposure to ionizing radiation include: a small increase in the possibility that a person exposed to X-rays will develop Cancer later in life. (General information for patients and health care providers on cancer detection and treatment is available from the National Cancer Institute.) tissue effects such as Cataracts, Skin Reddening, and Hair Loss , which occur at relatively high levels of radiation exposure and are rare for many types of imaging exams. For example, the typical use of a CT scanner or conventional radiography equipment should not result in tissue effects, but the dose to the skin from some long, complex interventional fluoroscopy procedures might, in some circumstances, be high enough to result in such effects. Another risk of X-ray imaging is possible reactions associated with an intravenously injected contrast agent, or “ Dye ", that is sometimes used to improve visualization. The risk of developing cancer from medical imaging radiation exposure is generally very small, and it depends on: radiation dose - The lifetime risk of cancer increases the larger the dose and the more X-ray exams a patient undergoes. patient's age - The lifetime risk of cancer is larger for a patient who receives X-rays at a younger age than for one who receives them at an older age. patient's sex - Women are at a somewhat higher lifetime risk than men for developing radiation-associated cancer after receiving the same exposures at the same ages. body region - Some organs are more radiosensitive than others.

23. Is it safe to have an X-ray during pregnancy ? The possibility of an X-ray during pregnancy causing harm to your unborn child is very small. Generally, the benefits of the diagnostic information from an X-ray outweigh the potential risk to a baby. However, if you received a large number of abdominal X-rays over a short period before you were aware of your pregnancy, your baby could be affected. Most X-ray exams — including those of the legs, head, teeth or chest — won't expose your reproductive organs to the direct X-ray beam, and a lead apron can be worn to provide protection from radiation scatter. The exception is abdominal X-rays, which expose your belly — and your baby — to the direct X-ray beam. The risk of harm to your baby depends on your baby's gestational age and the amount of radiation exposure. Exposure to extremely high-dose radiation in the first two weeks after conception might result in a miscarriage . However, these dose levels aren't used in diagnostic imaging. Exposure to high-dose radiation two to eight weeks after conception might increase the risk of fetal growth restriction or birth defects . Exposure between weeks 8 and 16 might increase the risk of a learning or intellectual disability . But the typical dose of a single radiation exposure associated with a diagnostic X-ray is much lower than the high dose associated with these complications. Before having an X-ray, tell your doctor if you are or might be pregnant. Depending on the circumstances, it might be possible to postpone the X-ray or modify it to reduce the amount of radiation. In addition, if you have a child who needs an X-ray, don't hold your child during the exam if you are or might be pregnant. If you had a diagnostic X-ray before you knew you were pregnant, talk to your health care provider. Source : www.mayoclinic.org

24. The main Chest Projections are the following: 1) Postero -anterior (PA) – the ray enters the posterior aspect of the patient and exits the anterior 2) Antero-posterior (AP) – the ray enters the anterior aspect and exits the posterior 3) Lateral 4) Obliques – either anterior or posterior – to demonstrate mediastinum or ribs 5) Penetrated postero -anterior 6) Inspiration/expiration postero -anterior – for pneumothorax, inhaled foreign bodies, or for diaphragmatic movement 7) Apical lordotic

25. Technical Aspects in CXR : 1. Rotation : In a properly centred film, the medial ends of the clavicles should be equidistant from the vertebral spinous processes at D4/D5 level. A rotated film is not properly centred film and the lung area nearest to the film appears less translucent. 2. Penetration : In an adequately penetrated film, the vertebral bodies and disc spaces should be just visible up till D8/D9 level. In an over penetrated film, all thoracic vertebrae are visible behind the heart shadow and lungs appear darker. In an under penetrated film, no vertebrae are visible. 3. Degree of Inspiration : When anterior ends of the sixth ribs or posterior ends of the tenth rib are above the right hemi diaphragm, it is said to be adequate. On an expiratory film, the heart shadow appears larger and there is crowding of bronchovascular markings in the basal regions. 4. Artefacts : Radiographic artefacts due to techniques, hair artefacts, external medical devices, nasogastric tubes, clothes, etc.

26. The chest x-ray is the most frequently requested radiologic examination. In fact every radiologst should be an expert in chest film reading. The interpretation of a chest film requires the understanding of Basic Principles . Normal anatomy and variants. Systematic approach to the chest film using an inside-out approach. Pathology of the heart, mediastinum, lungs and pleura, chest wall and abdomen.

27. Ideal CXR The medial ends of the clavicles should be equidistant from the vertebral column The trachea should be in the midline The scapulae should be off the lung fields There should be 10 posterior ribs visible above the diaphragm Five centimeter of lung apices should be above the clavicles Both costophrenic angles should be included on the film

28. Approach to CXR Basics • ID: patient name, medical record number (MRN), sex, age • date of exam • markers: right and/or left • technique: view (e.g. PA, AP, lateral), supine or erect • indications for the study • comparison: date of previous study for comparison (if available) • quality of film: inspiration (6th anterior and 10th posterior ribs should be visible), penetration (thoracic spine should be visible) and rotation (spinous processes should be equidistant from medial ends of clavicles)

29. Analysis • tubes and lines: check position and be alert for pneumothorax or pneumomediastinum • soft tissues: neck, axillae, pectoral muscles, breasts/nipples, chest wall ■ nipple markers can help identify nipples (may mimic lung nodules) ■ amount of soft tissue, presence of masses, presence of air (subcutaneous emphysema) • abdomen ■ free air under the diaphragm, air-fluid levels, distention in small and large bowel ■ herniation of abdominal contents (i.e. diaphragmatic hernia) • bones: C-spine, thoracic spine, scapulae, ribs, sternum, clavicles, proximal humerus ■ lytic and sclerotic lesions, fractures • mediastinum: trachea, heart, great vessels ■ cardiomegaly (cardiothoracic ratio >0.5), tracheal shift, tortuous aorta, widened mediastinum • hila: pulmonary vessels, mainstem and segmental bronchi, lymph nodes • lungs: parenchyma, pleura, diaphragm ■ abnormal lung opacity, pleural effusions or thickening ■ right hemidiaphragm usually higher than left due to liver ■ right vs. left hemidiaphragm can be discerned on lateral CXR due to heart resting directly on left hemidiaphragm

30. Normal Chest

31. PA VS AP View

32. Cardiothoracic Ratio

33. Indications of CXR : Respiratory disease (e.g. respiratory distress syndrome) Cardiac disease Bronchiolitis Pneumonia Pulmonary tuberculosis Pneumothorax Trauma Foreign bodies Septic screen Confirming the location of line placement (e.g. PICC, ETT, NGT etc.) peripherally inserted central catheter= PICC endotracheal tube = ETT nasogastric tube = NGT

34. Umbilical venous catheters (UVCs) are commonly used in neonates for vascular access and should be carefully assessed for position on all neonatal films. Position An umbilical venous catheter generally passes directly superiorly and remains relatively anterior in the abdomen. It passes through the umbilicus, umbilical vein, left portal vein, ductus venosus, middle or left hepatic vein, and into the inferior vena cava. The tip should lie at the junction of the inferior vena cava with the right atrium. Anomalous positioning Anomalous positioning of the umbilical venous catheters is quite frequent. The catheters are inserted by the pediatrician without imaging guidance, and given the small size of infants (especially those requiring umbilical catheters), a small variation in length of catheter can result in significant malpositioning (too long). Alternatively, the catheter may not travel along the intended route (wrong turn). Too long If the umbilical venous catheter is advanced too far along its intended course, the tip may end up in a number of locations: 1. left atrium and beyond (through a patent foramen ovale or an atrial septal defect) 2. pulmonary vein 3. left ventricle 4. right atrium and beyond 5. superior vena cava 6. right ventricle Wrong turn If the umbilical venous catheter reaches the left portal vein but does not continue into the ductus venosus, the catheter can travel left into the more peripheral left portal vein or right, where it can eventually course into the right portal vein or hepatofugally into the main portal vein (or potentially farther into the vessels that merge to form the portal vein: the superior mesenteric and splenic veins). Malpositioning within the portal venous system is associated with portal vein thrombosis. Complications Some complications can occur in a well-positioned catheter. The most common of these is formation of thrombus along the catheter. 1. Malpositioned catheters may result in structural injury including: 2. hepatic hematoma from perforation of an intrahepatic vascular wall 3. pericardiac hematoma from perforation of the right or left atrial wall

35. Normal UVC and UAC positions

36. Interpretation of Chest X-Ray: 1. First look at name, age, sex of patient if provided in the film. Also try to seek some clinical information before interpreting. 2. Then check the technical aspects. 3. Costophrenic and cardiophrenic angles. 4. Cardiac size, borders and mediastinum. 5. Lung parenchyma. 6. Hila. 7. Trachea. 8. Diaphragms – also try to look below the diaphragms for stomach bubble, gas shadows and calcification if any. 9. Hidden areas. 10. Soft tissues. 11. Bones. 12. Four corners of the film.

37. Normal chest x-ray (6 year old)

38. Soft Vs Hard Film

39. Bronchiolitis

40. Pulmonary Congestion

41. Consolidation • pathogenesis: air in alveoli replaced by fluid (transudate, blood), inflammatory exudates, protein, or tumour • findings ■ air bronchograms: lucent branching bronchi visible through opacification ■ airspace nodules: fluffy, patchy, poorly defined margins with later tendency to coalesce, may take on lobar or segmental distribution ■ silhouette sign • differential diagnosis ■ fluid: transudate (pulmonary edema), blood (trauma, vasculitis, bleeding disorder, pulmonary infarct) ■ inflammatory exudates: bacterial infections, TB, allergic hypersensitivity alveolitis, COP (cryptogenic organizing pneumonia), allergic bronchopulmonary aspergillosis, aspiration, sarcoidosis ■ protein: pulmonary alveolar proteinosis ■ tumour : bronchoalveolar carcinoma, lymphoma • management: varies depending on the pattern of consolidation, which can suggest different etiologies; should also be done in the context of clinical picture

42. Interstitial Diseas e • pathogenesis: pathological process involving the interlobular connective tissue (i.e. “scaffolding of the lung”) • findings ■ septal thickening: fine lines caused by thickened connective tissue septae (most commonly due to pulmonary edema or lymphangitis carcinomatosis) ◆ these manifest on CXR as: – Kerley A: long thin lines in upper lobes – Kerley B: short horizontal lines extending from lateral lung margin – Kerley C: diffuse linear pattern throughout lung ■ nodular: 1-5 mm well-defined nodules distributed evenly throughout lung ◆ seen in malignancy, pneumoconiosis, and granulomatous disease (e.g. sarcoidosis, miliary TB) ■ reticular: fine curvilinear opacities ◆ seen in interstitial lung diseases (pulmonary fibrosis) ◆ watch for pneumothorax as a complication ■ reticulonodular: combination of reticular and nodular patterns ■ may also see signs of airspace disease (atelectasis, consolidation) • differential diagnosis ■ occupational/environmental exposure ◆ inorganic: asbestosis, coal miner’s pneumoconiosis, silicosis, berylliosis, talc pneumoconiosis ◆ organic: hypersensitivity pneumonitis, bird fancier’s lung, farmer’s lung ( mouldy hay), and other organic dust ■ autoimmune: connective tissue diseases (e.g. rheumatoid arthritis, scleroderma, SLE, polymyositis, mixed connective tissue disease), IBD, celiac disease, vasculitis ■ drug-related: antibiotics (cephalosporins, nitrofurantoin), NSAIDs, phenytoin, carbamazepine, fluoxetine, amiodarone, chemotherapy (e.g. methotrexate), heroin, cocaine, methadone ■ infections: non-tuberculous mycobacteria, certain fungal infections ■ idiopathic: hypersensitivity pneumonitis, IPF ■ for causes of Interstitial Lung Disease classified by distribution, see Respirology, R13 ■ management: high-resolution CT thorax and ± open lung biopsy

43. Pulmonary Nodule • findings ■ round opacity ± silhouette sign ■ note: do not mistake nipple shadows for nodules; if in doubt, repeat CXR with nipple markers • differential diagnosis ■ extrapulmonary density: nipple, skin lesion, electrode, pleural mass, bony lesion ■ solitary nodule ◆ tumour : carcinoma, hamartoma, metastasis, bronchial adenoma ◆ inflammation: histoplasmoma , tuberculoma, coccidioidomycosis ◆ vascular: AV fistula, pulmonary varix (dilated pulmonary vein), infarct, embolism ■ multiple nodules: metastases, abscess, granulomatous lung disease (TB, fungal, sarcoid, rheumatoid nodules, silicosis, GPA) • management: clinical information and CT appearance determine level of suspicion of malignancy ■ if high probability of malignancy, invasive testing (fine needle aspiration, transbronchial/ transthoracic biopsy) is indicated ■ if low probability of malignancy, follow-up imaging as per Fleischner guidelines 2017

44. Pulmonary Edema • pathogenesis: fluid accumulation in the airspaces of the lungs • findings ■ vascular redistribution/enlargement, cephalization, pleural effusion, cardiomegaly (may be present in cardiogenic edema and fluid overloaded states) ■ fluid initially collects in interstitium • loss of definition of pulmonary vasculature • peribronchial cuffing • Kerley B lines • reticulonodular pattern • thickening of interlobar fissures ■ as pulmonary edema progresses, fluid collects in alveoli and causes diffuse airspace disease, often in a “bat wing” or “butterfly” pattern in perihilar regions (outermost lung fields tend to be spared) • differential diagnosis: cardiogenic (e.g. CHF), renal failure, volume overload, non-cardiogenic (e.g. ARDS)

45. Pulmonary Embolism • pathogenesis: blockage in the pulmonary arteries due to emboli from pelvic or leg veins, rarely from central venous catheters, air, fat, or amniotic fluid • findings ■ generally not possible to definitively diagnose on plain film; diagnosis made by CT pulmonary angiography or ventilation/perfusion scintigraphy (VQ scan) ■ CXR: Westermark sign (localized pulmonary oligemia), Hampton’s hump (triangular peripheral infarct), enlarged right ventricle and right atrium, atelectasis, pleural effusion, and rarely pulmonary edema ■ definitive imaging study: CT pulmonary angiography to look for filling defect in contrast-filled pulmonary arteries ■ VQ scan: can be used in patients with impaired renal function or in pregnancy

46. Pleural Effusion • a horizontal fluid level is seen only in a hydropneumothorax (i.e. both fluid and air within pleural cavity) • effusion may exert mass effect, shift trachea and mediastinum to opposite side, or cause atelectasis of adjacent lung • U/S is superior to plain film for detection of small effusions and may also aid in thoracentesis; POCUS is now standard of care in acute situations

47. Pneumothorax • pathogenesis: gas/air accumulation within the pleural space resulting in separation of the lung from the chest wall • findings ■ upright chest film allows visualization of visceral pleura as curvilinear line paralleling chest wall, separating partially collapsed lung from pleural air ■ more obvious on expiratory (increased contrast between lung and air) or lateral decubitus films (air collects superiorly) ■ more difficult to detect on supine film; look for the “deep (costophrenic) sulcus” sign, “double diaphragm” sign (dome and anterior portions of diaphragm outlined by lung and pleural air, respectively), hyperlucent hemithorax, sharpening of adjacent mediastinal structures ■ contralateral tracheal and mediastinal shift may occur in tension pneumothorax • differential diagnosis: spontaneous (tall and thin males, smokers), iatrogenic (lung biopsy, ventilation, central venous catheter insertion, thoracentesis), trauma (associated with rib fractures), emphysema, malignancy, honeycomb lung • management: supplemental oxygen and observation, chest tube insertion in 5th ICS anterior axillary line, or emergent needle decompression in 2nd ICS midclavicular line if tension pneumothorax (followed by chest tube insertion); repeat CXR to ensure resolution

48. Mediastinal Mass • Felson’s method of division outlines three compartments, which provides an approach to the differential diagnosis of a mediastinal mass • anterior compartment is bordered anteriorly by the sternum and posteriorly by the heart and great vessels ■ 4 Ts: thyroid, thymic neoplasm, teratoma, terrible lymphoma ■ cardiophrenic angle mass differential: thymic cyst, epicardial fat pad, foramen of Morgagni hernia • middle compartment extends from the posterior border of anterior mediastinum to a line 1 cm posterior to the anterior edge of thoracic vertebral bodies ■ esophageal carcinoma, esophageal duplication cyst, metastatic disease, lymphadenopathy (all causes), hiatus hernia, bronchogenic cyst • posterior border (posterior to the middle line described above) ■ neurogenic tumour (e.g. neurofibroma, schwannoma), neurenteric cyst, thoracic duct cyst, lateral meningocele, Bochdalek hernia, extramedullary hematopoiesis • any compartment may give rise to lymphoma, lung cancer, aortic aneurysm or other vascular abnormalities, abscess, or hematoma

49. Enlarged Cardiac Silhouette • heart borders ■ on PA view, right heart border is formed by right atrium; left heart border is formed by left atrium and left ventricle ■ on lateral view, anterior heart border is formed by right ventricle; posterior border is formed by left atrium (superior to left ventricle) and left ventricle • cardiothoracic ratio = greatest transverse dimension of the central shadow relative to the greatest transverse dimension of the thoracic cavity ■ using a good quality erect PA chest film in adults, cardiothoracic ratio of >0.5 is abnormal ■ differential of ratio >0.5 ◆ cardiomegaly (myocardial dilatation or hypertrophy) ◆ pericardial effusion ◆ poor inspiratory effort/low lung volumes ◆ pectus excavatum ■ ratio <0.5 does not exclude enlargement • pericardial effusion: globular heart with loss of indentations on left mediastinal border • RA enlargement: increase in curvature of right heart border and enlargement of SVC • LA enlargement: straightening of left heart border; increased opacity of lower right side of cardiovascular shadow (double heart border); elevation of left main bronchus (specifically, the upper lobe bronchus on the lateral film), distance between left main bronchus and “double” heart border >7 cm, splayed carina (late sign) • RV enlargement: elevation of cardiac apex from diaphragm; anterior enlargement leading to loss of retrosternal air space on lateral; increased contact of right ventricle against sternum • LV enlargement: rounding of the cardiac apex; displacement of left cardiac border leftward, inferiorly, and posteriorly

50. Tubes, Lines, and Catheters • ensure appropriate placement and assess potential complications of lines and tubes • avoid mistaking a line/tube for pathology (e.g. oxygen rebreather mask for pneumothoraces ) Central Venous Catheter • used for fluid and medication administration, vascular access for hemodialysis, and CVP monitoring • ideally located at the SVC/atrial junction to prevent inducing arrhythmias or perforating wall of atrium ■ if monitoring CVP, catheter tip must be proximal to venous valves • tip of well-positioned central venous catheter projects over silhouette of SVC in a zone demarcated superiorly by the anterior first rib end and clavicle, and inferiorly by top of RA • course should parallel that of the SVC; if appears to bend as it approaches wall of SVC or appears perpendicular, catheter may damage and ultimately perforate wall of SVC • complications: pneumothorax, bleeding (mediastinal, pleural), malposition (artery, pleura), air embolism Endotracheal Tube • frontal chest film: tube projects over trachea and shallow oblique or lateral chest radiograph will help determine position in 3 dimensions • progressive gaseous distention of stomach on repeat imaging is concerning for esophageal intubation • tip should be located 2-4 cm above tracheal carina (avoids bronchus intubation and vocal cord irritation) • maximum inflation diameter <3 cm to avoid necrosis of tracheal mucosa and rupture; ensure diameter of balloon is less than tracheal diameter above and below balloon • complications: aspiration (parenchymal opacities), pharyngeal perforation (subcutaneous emphysema, pneumomediastinum, mediastinitis)

51. Nasogastric Tube • tip and side port should be positioned distal to esophagogastric junction and proximal to gastric pylorus • radiographic confirmation of tube is mandatory because clinical techniques for assessing tip position may be unreliable • complications: aspiration (parenchymal opacities), pneumothorax Swan-Ganz Catheter • to monitor pulmonary capillary wedge pressure and estimate diastolic filling of left heart • tip should be positioned within right or left main pulmonary arteries or in one of their large, lobar branches • if tip is located more distally, increased risk of prolonged pulmonary artery occlusion resulting in pulmonary infarction or, rarely, pulmonary artery rupture/aneurysm • complications: pneumothorax, bleeding (mediastinal, pleural), air embolism Chest Tube • in dorsal and caudal portion of pleural space to evacuate fluid • in ventral and cephalad portions of pleural space to evacuate pneumothoraces • tube may lie in fissure as long as functioning • complications: bleeding, infection, lung laceration

52. Pneumonia

53. Pneumonia

54. Staph pneumonia multilobar consolidation, cavitation, pneumatoceles, spontaneous pneumothorax.

55. Pneumatocele are intrapulmonary gas-filled cystic spaces that can have a variety of sizes and appearances. They may contain gas-fluid levels and are usually the result of ventilator-induced lung injury in neonates or post-infectious. They should not be mistaken for a cavitating lung mass. Pathology The majority of pneumatoceles occur as a result of pneumonia (post-infectious pneumatocele). The causative agents include: 1. Staphylococcus aureus (most common) 2. Streptococcus pneumoniae 3. Haemophilus influenzae 4. Escherichia coli 5. group A streptococci 6. Klebsiella pneumoniae 7. adenovirus 8. primary pulmonary tuberculosis 9. COVID-19 (infrequent) In addition to infection, pneumatoceles are also seen in a number of other settings, including: 1- trauma: traumatic pulmonary pseudocyst / traumatic pneumatocoele (separate article) 2- positive pressure ventilation, especially in preterm neonates 3- hydrocarbon ingestion Three main theories have been put forward to explain the formation of pneumatoceles : 1- pulmonary overinflation caused by transient bronchial/bronchiolar obstruction and a ball-valve effect 2- drainage of necrotic lung parenchyma with subsequent enlargement secondary to a ball-valve effect 3- focal collections of air within the pulmonary interstitium following inflammation and necrosis of the airway wall and fistula formation with the pleura

56. Pneumatocele

57. Fungal Pneumonia

58. Miliary TB

59. Miliary TB

60. Mycoplasma Pneumoniae Chest X Ray

61. Pneumothorax

62. Diaphragmatic Hernia

63. Diaphragmatic Hernia

64. Post-Traumatic Diaphragmatic Hernia

65. Thymus Gland

66. Thymoma is the most common tumour of the anterior mediastinum with an incidence of 0.10–0.18 per 100 000. Overall, 35–50% of patients with thymomas have myasthenia gravis, while 12% of patients with myasthenia gravis have a thymoma. Approximately 50% of individuals presenting with thymomas are clinically asymptomatic. Symptoms include chest pain, cough, dyspnoea and muscle fatigue (characteristic of myasthenia gravis). Less common symptoms, such as superior vena cava syndrome, phrenic nerve paralysis or recurrent laryngeal nerve involvement resulting in hoarseness, are indicative of malignant disease. The differential diagnoses of anterior mediastinal masses include lymphoma, retrosternal thyroid and germ cell tumours . Patients with a suspected mediastinal mass as suggested in should undergo CT scan. There were no features to suggest invasion into surrounding structures and in such cases complete surgical resection should be attempted .Grade A or AB tumours of Masaoka stage I or II do not require adjuvant treatment.1 2 However, neoadjuvant therapy should be considered for patients with large or invasive tumours . Surgical resection or debulking with adjuvant chemo-radiotherapy reduces the risk of recurrence in those with stage III (local invasion) or stage IV (distant metastases) disease.3 Predictors of long-term survival include complete surgical resection, stage, histological grade and size of tumour . Intra-thoracic recurrence is more likely in advanced stages but overall cause of death is unrelated to thymoma in 65% of patients.

67. The Thymic Sail sign is a normal feature of the Thymus Gland on a neonatal frontal chest radiograph. The thymic sail sign represents a triangular-shaped inferior margin of the normal thymus seen on a neonatal frontal chest radiograph. It is more commonly seen on the right side, but can also be bilateral. It is seen in 3-15% of all cases. This sign should not be confused with the spinnaker sail sign which indicates a pneumomediastinum.

68. Thymoma

69. Thymoma

70. The Spinnaker Sign (also known as the angel wing sign) is a sign of Pneumomediastinum seen on neonatal chest radiographs. It refers to the thymus being outlined by air with each lobe displaced laterally and appearing like spinnaker sails. This is distinct from the sail sign appearance of the normal thymus The thymic spinnaker sail sign was first described by John E Moseley (1909-1996) in 1960 3. John Moseley was a bone radiologist who spent most of his career at New York City's Mount Sinai Hospital. He was the first African-American member of the Society of Pediatric Radiology and New York Roentgen Ray Society .

71. Mediastinal Masses

72. Mediastinal Masses : Statistically, it is important to remember the following : Most masses (> 60%) are: Thymomas Neurogenic Tumors Benign Cysts Lymphadenopathy (LAD) In children the most common (> 80%) are: Neurogenic tumors Germ cell tumors Foregut cysts In adults the most common are: Lymphomas LAD = Lymphadenopathy Thymomas Thyroid masses

73. Anterior mediastinal mass T Cell Lymphoma

74. Anterior Mediastinal Mass Lymphoma

75. lymphoblastic leukemia

76. Thoracic aortic aneurysm

77. Ascending Aortic Aneurysm and Cardiomegaly

78. Diaphragmatic eventration Diaphragmatic eventration refers to an abnormal contour of the diaphragmatic dome with no disruption to the diaphragmatic continuity. It typically affects only a segment of the hemidiaphragm, compared to paralysis/weakness where the entire hemidiaphragm is typically affected. Associations Unilateral eventration 1. Beckwith-Wiedemann syndrome 2. trisomy 13, 14, 15 or 18 Bilateral eventration 1. toxoplasmosis 2. cytomegalovirus (CMV) 3. arthrogryposis 4. Werdnig-Hoffman disease Clinical presentation In newborns, eventration of the diaphragm is a recognized cause of respiratory distress. However in adults, it is often asymptomatic . Pathology Diaphragmatic eventration may be congenital or acquired in nature. It occurs due to incomplete muscularisation of the diaphragm with a thin membranous sheet replacing normal diaphragmatic muscle. Over time this region stretches and on inspiration does not contract normally. Etiology Congenital 1. phrenic nerve agenesis 2. failure of myotomes to migrate to a localized area in the diaphragm leading to abnormal muscularisation Acquired 1. trauma/surgery/birth trauma leading to phrenic nerve paralysis (most common cause) Location Congenital eventration is frequently seen in the anteromedial portion of the right hemidiaphragm, while acquired eventration is frequently seen in the left hemidiaphragm. Total eventration is most commonly seen in the left hemidiaphragm .

79. Radiographic features Plain radiograph Elevation of the affected portion of the diaphragm is usually seen as a smooth hump, while the remainder of the hemidiaphragm contour is normal. The frontal x-ray may show a 'double' diaphragmatic contour, which is easily confirmed on the lateral projection. CT There may be a sharp border between the eventrated portion and the remainder of the hemidiaphragm . Differential diagnosis Possible considerations on plain film include: lung • consolidation (e.g. round pneumonia) • lung mass • collapse • pulmonary infarction pleura • subpulmonic pleural effusion • pleural mass diaphragmatic mass diaphragmatic rupture Morgagni hernia subdiaphragmatic region • liver/stomach mass • subdiaphragmatic collection phrenic nerve palsy hemiplegia

80. Diaphragmatic eventration

81. Diaphragmatic eventration

82. Pneumo pericardium

83. Tumours Metastasizing to Lungs in Children : 1. Wilm’s tumor. 2. Osteosarcoma. 3. Ewing’s sarcoma. 4. Rhabdomyosarcoma. 5. Lymphoma. 6. Leukaemia . 7. Neuroblastoma. 8. Germ cell tumors.

84. Unilateral pulmonary edema and the presence of a chest tube in the right thorax suggest reexpansion pulmonary edema as the diagnosis.

85. Lung Atelectasis

86. Lung Atelectasis

87. Sail Sign

88. Pulmonary Oedema

89. Lung abscess

90. Subcutaneous emphysema

91. References : 1- The Chest X-Ray: A Survival Guide by Gerald de Lacey et al. 2- introduction to chest radiology 3- Fleischner Society: Glossary of Terms for Thoracic Imaging by David M. Hansell et al Radiology 2008;246:697 4- Lines and Stripes: Where Did They Go? From Conventional Radiography to CT by Jerry M. Gibbs et al RadioGraphics 2007;27:33-48 5- Cardiac Valves: Assessment and Identification on RadDaily.com 6- A Diagnostic Approach to Mediastinal Abnormalities by Camilla R. Whitten May 2007 RadioGraphics , 27,657-671. 7- The Deep Sulcus Sign Radiology 2003; 228:415-416 8- Chest Radiology Plain Film Patterns and Differential Diagnoses by James C. Reed 9- Thoracic Imaging: Pulmonary And Cardiovascular Radiology by Richard Webb and Charles Higgins 10- Lesions of the Cardiophrenic Space: Findings at Cross-sectional Imaging Víctor Pineda et al. January 2007 RadioGraphics,27, 19-32. 11- Imaging of Cystic Masses of the Mediastinum By Mi-Young Jeung , et al. October 2002 RadioGraphics,22, S79-S93.

92. Thank You