Diagnostic Imaging AI Flashcards
Why are higher exposure factors needed when using a grid?
Higher exposure factors (higher mAs) are needed when using a grid to increase the quantity of primary X-ray photons.
What is the purpose of the lead shutters in the X-ray collimator?
The lead shutters in the X-ray collimator are used to adapt the size of the radiographic field to the body area being radiographed.
Why are intensifying screens used in conventional (screen-film) radiography?
Intensifying screens are used in conventional radiography to amplify the effect of X-rays, as the radiographic film is poorly sensitive to X-rays.
Where are the intensifying screens integrated in screen-film radiography?
The intensifying screens are integrated into both sides of the light-proof X-ray cassette, with the radiographic film placed in between.
What are the two important properties of intensifying screens?
The two important properties of intensifying screens are speed (ability to produce light and amplify the effect of X-rays) and sharpness (spatial resolution).
When are fast screens preferred in radiography?
Fast screens are preferred for large body parts (abdomen) or when movement artifacts are an issue (thorax).
Why is it recommended to have both fast and slow screens/cassettes available?
It is recommended to have both fast and slow screens/cassettes available to optimize image detail and resolution for different body areas (e.g. long bones).
What are the five sequential steps in film processing?
The five sequential steps in film processing are developing, rinsing, fixing, rinsing, and drying.
What are the two main types of digital radiography systems?
The two main types of digital radiography systems are computed radiography (CR) and direct digital radiography (DDR).
How does computed radiography (CR) work?
Computed radiography (CR) uses imaging cassettes containing a ‘storage phosphor’ plate that stores the absorbed X-ray energy in crystals and is later read by a machine using a laser beam.
What is the key difference between computed radiography (CR) and direct digital radiography (DDR)?
The key difference is that CR systems require a plate reader to scan and erase the storage phosphor plate, while DDR systems capture the radiographic image directly without using a plate reader.
What are some advantages of digital radiography over conventional radiography?
Some advantages of digital radiography over conventional radiography include higher contrast resolution, image manipulation capabilities, fewer exposures needed, quicker process, and easier image storage and sharing.
In what format are digital images stored in digital radiography?
Digital images in digital radiography are stored as computer files in DICOM format.
What is the importance of centring and positioning in radiography?
Centring and positioning in radiography is important to ensure that the body part being radiographed is well positioned and that unwanted rotation is avoided. This helps in obtaining accurate and clear radiographic images.
Give an example of superimposition on a dorsoventral projection of the thorax.
On a dorsoventral projection of the thorax, the sternum should be superimposed with the thoracic spine.
What should be superimposed with each other on lateral projections of the thorax?
On lateral projections of the thorax, the costochondral junctions should be superimposed with each other.
What should be superimposed with each other on lateral projections of the lumbar spine or abdomen?
On lateral projections of the lumbar spine or abdomen, the transverse processes of the lumbar vertebrae should be superimposed with each other.
Why is it important to avoid unnecessary superimposition of the surrounding anatomy onto the radiographic image?
Avoiding unnecessary superimposition of the surrounding anatomy onto the radiographic image is important to obtain a clear and unobstructed view of the specific body part being examined.
What are artefacts in radiography?
Artefacts in radiography are abnormalities or distortions that can appear on a radiograph, which do not represent actual structures. They can affect the appearance of the image and may lead to diagnostic errors if not recognized as artefacts.
What are some examples of artefacts that can occur in digital radiography?
In digital radiography, some artefacts that can occur include grainy images due to under-exposure, loss of structure margins with over-exposure, radiolucent halo surrounding metal implants (Uberschwinger artefact), ghost images from incomplete erasure of the CR plate, and moire artefact (bands seen across the image) resulting from interference between the sampling frequency and grid lines.
What are the biologic effects of X-rays?
X-rays are a form of ionising radiation that can cause harm to living tissues. They can ionise atoms and interfere with the molecular chemistry of cells, resulting in cellular damage. The specific effects depend on the tissue irradiated, characteristics of the radiation, dose received, and duration of exposure.
What is the basic structure of the X-ray tube?
The X-ray tube is composed of the cathode (source of electrons) and the anode (tungsten target), housed in a vacuum glass envelope surrounded by oil and lead housing.
What is the function of the cathode in the X-ray tube?
The cathode is a wire filament made of tungsten and it heats up to form a cloud of free electrons when a small electrical current is passed through it.
What is the function of the anode in the X-ray tube?
The anode is a tungsten target that releases X-rays when collided with accelerated electrons.
What is the purpose of the X-ray generator?
The X-ray generator provides the electrical power to accelerate the electrons in the X-ray tube and produce X-rays.
What are the principle interactions of X-rays with matter?
The principle interactions of X-rays with matter include absorption, scattering, and transmission.
What is the influence of kilovoltage on image contrast?
Higher kilovoltage results in lower image contrast, while lower kilovoltage results in higher image contrast.
How can scatter radiation be reduced?
Scatter radiation can be reduced by using grids, collimators, and lead shielding.
What are the key differences between conventional, computed, and direct digital radiography?
Conventional radiography uses film, computed radiography uses imaging plates, and direct digital radiography uses digital detectors.
Why are pregnant women not permitted to enter radiography rooms?
Pregnant women are not permitted to enter radiography rooms because exposure to radiation can be harmful to the developing fetus.
What are the three main sources of radiation in diagnostic radiology?
The three main sources of radiation in diagnostic radiology are the primary beam, scattered radiation, and leakage radiation from the X-ray tube.
What is the purpose of lead clothing in radiography?
Lead clothing provides protection from scattered radiation, not the primary beam. It should never be placed within the primary beam, even if protected.
How can exposure to ionizing radiation be reduced?
Exposure to ionizing radiation can be reduced by minimizing exposure time, increasing distance from the source of radiation, and using barriers containing materials that absorb X-rays.
What is the principle of the inverse square law in radiography?
The inverse square law states that the intensity of radiation at a given point is inversely proportional to the square of the distance between that point and the source of the radiation.
What is the goal of using barriers in radiography?
The goal of using barriers is to reduce radiation dose as much as possible. Lead is commonly used as a barrier material to absorb X-rays.
What legislation governs the use of X-rays in veterinary practice?
The use of X-rays in veterinary practice is governed by the Ionising Radiations Regulations 2017 (IRR17), the associated Approved Code of Practice, and Guidance Notes for the Protection of Persons against Ionising Radiations arising from Veterinary Use.
Why is regular image back-up and retrieval important in digital radiography?
Regular image back-up and retrieval are important in digital radiography to ensure that images are not lost and can be accessed when needed.
What are the potential storage issues when printing digital radiographs onto paper or film?
Printing digital radiographs onto paper or film can impact cost savings and lead to similar storage issues as with conventional radiographs.
What is the importance of acquiring radiographs of good diagnostic quality?
Acquiring radiographs of good diagnostic quality reduces the chance of missing or misinterpreting a lesion.
According to an eminent veterinary radiologist, what are poor radiographs considered to be?
According to an eminent veterinary radiologist, poor radiographs are considered to be either totally useless or totally misleading.
Why is it necessary to take two orthogonal projections for complete radiographic evaluation of an object?
Taking two orthogonal projections allows for the assessment of all three dimensions of a three-dimensional object.
What is distortion in radiography and how can it be minimized?
Distortion in radiography occurs when a three-dimensional object is converted into a two-dimensional image. It can be minimized by keeping the object close to the image receptor, ensuring proper positioning, and centering the X-ray beam.
What factors should be considered when evaluating radiographic image quality?
The factors that should be considered when evaluating radiographic image quality include density, contrast, sharpness, centring and collimation, and positioning.
What can cause a conventional radiograph to be too pale or too dark?
A conventional radiograph can be too pale due to under-exposure or under-development and too dark due to over-exposure or over-development.
What are the factors that affect X-ray beam attenuation?
The factors that affect X-ray beam attenuation are tissue thickness, tissue composition (density and atomic number), and X-ray energy (kV).
What are the five types of opacity detected on a radiograph, from darkest to brightest?
The five types of opacity detected on a radiograph, from darkest to brightest, are air/gas, fat, soft tissue/fluid, bone/mineral, and metal.
Why can soft tissues and fluid not be differentiated on a radiograph?
Soft tissues and fluid cannot be differentiated on a radiograph because they have the same opacity.
What determines the contrast obtained with the photoelectric effect?
The differences in density and atomic number between tissue types determine the contrast obtained with the photoelectric effect.
What effect does the Compton effect have on image contrast?
The Compton effect decreases image contrast by producing scattered X-rays, causing a diffuse blackening of the radiographic image.
How does the contrast of the radiographic image vary with the selected kilovoltage (kV)?
The contrast of the radiographic image progressively decreases as the kilovoltage (kV) increases.
What technique is preferred for abdominal radiography to maximize contrast between fat and soft tissue?
For abdominal radiography, it is preferred to use a low kilovoltage (kV) and a high milliamperes-second (mAs) to promote the photoelectric effect and maximize contrast between fat and soft tissue.
What are the main methods of scatter reduction in radiography?
The main methods of scatter reduction in radiography are using a grid, collimation to keep the radiographic field size small, and using a lower kilovoltage (kV) if possible/appropriate.
What is the purpose of a step-up transformer in the X-ray machine?
The purpose of a step-up transformer is to convert low input voltage into high output voltage through the process of electromagnetic induction.
What type of current is required for the X-ray machine?
The X-ray machine requires an AC or alternating current.
What is the role of a diode in a rectifier circuit?
A diode is an electrical component that only allows current to flow in one direction in a rectifier circuit.
How many diodes are typically used in a rectifier circuit?
Four diodes are typically used in a rectifier circuit.
What is the purpose of a rectifier circuit in the X-ray generator?
The rectifier circuit ensures that electrons always flow in the correct direction across the X-ray tube, regardless of the change in polarity caused by the alternating current.
What is the advantage of using rectifier circuits in X-ray generation?
Rectifier circuits produce a rectified waveform, which allows X-ray production throughout the entire AC cycle and improves efficiency.
What are the three main types of X-ray generator designs?
The three main types of X-ray generator designs are single-phase, three-phase, and high-frequency generators.
What is the main interaction of X-rays with matter when they have low energy?
The main interaction of X-rays with matter when they have low energy is through absorption, specifically the photoelectric effect.
What is saturation artifact?
Saturation artifact refers to the complete black appearance of soft tissues on over-exposed digital radiographs, which cannot be corrected by image manipulation.
What is contrast in radiography?
Contrast is the difference in density between two adjacent areas on a radiograph.
What factors affect the contrast of an image?
The inherent contrast of the body part, energy of the X-ray photons, amount of scattered radiation reaching the film, and characteristics of the screen-film combination or digital filter/algorithm used.
How can image contrast be improved?
Image contrast can be improved by using a lower kV, reducing scatter with techniques such as collimation and using a grid, and correcting any processing errors in conventional radiography.
What is sharpness in radiography?
Sharpness refers to the ability to distinguish the edges of structures and small details.
What are the three main types of radiographic unsharpness?
The three main types of radiographic unsharpness are movement blur, geometric unsharpness, and screen unsharpness.
What causes movement blur in radiographs?
Movement blur can be caused by patient motion or movement of the table or image receptor.
How can movement blur be reduced?
Movement blur can be reduced by keeping the exposure time as low as possible and using sedation or general anesthesia when necessary.
What is thermionic emission?
Thermionic emission is the release of electrons from a heated cathode.
What is the purpose of the focussing cup in an X-ray tube?
The focussing cup keeps the cloud of electrons tightly together in a beam.
How are the electrons accelerated towards the anode in an X-ray tube?
The electrons are accelerated by applying a large potential difference (or voltage) across the X-ray tube.
What are the two types of anode found in X-ray machines?
The two types of anode are stationary anode and rotating anode.
How does a rotating anode differ from a stationary anode?
A rotating anode has a higher heat loading capacity and is more resistant to heat damage than a stationary anode.
What are the three key parameters adjustable on the control console of an X-ray generator?
The three key parameters are kilovoltage (kV), tube current (mA), and exposure time (seconds).
How does the kilovoltage (kV) affect X-ray production?
The higher the kilovoltage (kV), the higher the energy of the X-rays produced.
What is the composite factor mAs in X-ray production?
The composite factor mAs is the product of tube current (mA) and exposure time (seconds), affecting the quantity of X-rays produced.
Which cells are the most sensitive to radiation?
The most sensitive cells to radiation are cells in the gonads, bone marrow, and epithelial tissues.
Why are muscle and nervous tissue more resistant to radiation?
Muscle and nervous tissue are more resistant to radiation because they are composed of well differentiated cells.
How does the cell environment affect radiosensitivity?
The presence of oxygen enhances free radical damage and increases radiosensitivity due to the formation of reactive oxygen species.
What are the two types of biologic effects of ionising radiation exposure?
The two types of biologic effects are deterministic effects (or tissue reactions) and stochastic effects.
What are deterministic effects of ionising radiation?
Deterministic effects are directly related to the absorbed radiation dose and have a threshold dose below which the effect does not occur.
What are some consequences of local irradiation?
Local irradiation can result in immediate effects like inflammation and necrosis, or delayed effects like atrophic fibrosis.
What are stochastic effects of ionising radiation?
Stochastic effects are random chance events caused by radiation-induced cellular mutations that can result in cancer or hereditary/genetic effects.
Why are stochastic effects of ionising radiation considered potentially harmful?
Stochastic effects have no threshold dose and can occur even with very low doses, making every irradiation potentially harmful.
What legislation implements the worker safety aspects of the Basic Safety Standards Directive?
Ionising Radiations Regulations 1999 (IRR99)
What is the title of the Approved Code of Practice that accompanies IRR17?
Work with ionising radiation: Ionising Radiations Regulations 2017. Approved Code of Practice and Guidance
What do the Guidance Notes for the Protection of Persons against Ionising Radiations provide?
Practical methods of working with X-rays in veterinary practice that afford a high level of radiation protection
What is the purpose of the legislation, code of practice, and guidance notes?
To protect the patient and personnel from hazards arising from the use of ionising radiation, and to describe safe working practice
What must a veterinary practice using X-rays do?
Notify the Health and Safety Executive
Who is responsible for ensuring that all work with X-rays is carried out safely in a veterinary practice?
Internal Radiation Protection Supervisor (RPS)
What role does the Radiation Protection Advisor (RPA) have?
Assist the RPS in setting up a safe system of work within the practice
What should be placed above all doorways leading to the controlled area?
Radiation trefoil signs
What is the first step in evaluating radiographs?
The first step in evaluating radiographs is to decide if the study is adequate and diagnostic.
How can you reduce the risk of missing a lesion in a radiograph?
Developing a consistent routine and being methodical when evaluating radiographs can help reduce the risk of missing a lesion.
What is ‘satisfaction of search’ in radiographic interpretation?
‘Satisfaction of search’ is when an obvious lesion is found and the rest of the image is not thoroughly examined.
What should be taken into consideration when re-evaluating a radiograph?
When re-evaluating a radiograph, the signalment of the animal, the history, and the clinical signs should be taken into consideration.
Why should radiographs always be oriented in the same direction?
Radiographs should be oriented in the same direction for consistency, which enables the reader to become more familiar with how a certain body part should appear in the image.
What is the recommended order to evaluate structures on a thoracic radiograph?
The recommended order to evaluate structures on a thoracic radiograph is: 1) Soft tissues surrounding the thorax, including the visible portion of the abdomen 2) The visible skeletal structures 3) The lungs and trachea / bronchi 4) The pleural space 5) The cardiac silhouette 6) The pulmonary blood vessels and great vessels 7) The mediastinum
What are the rules for radiographic orientation?
The rules for radiographic orientation are: Lateral views - cranial / rostral.
What are the two abnormalities that can be identified with contrast radiography?
The two abnormalities that can be identified with contrast radiography are filling defects and contrast leakage.
What can cause filling defects in contrast radiography?
Filling defects in contrast radiography can be caused by intestinal foreign bodies, uroliths, blood clots, and gas bubbles in the urinary tract, and tumors affecting the wall of the gastrointestinal or urinary tract.
What is contrast leakage in contrast radiography?
Contrast leakage in contrast radiography is confirmed when the contrast agent can be seen in an area that should not normally contain contrast. It can occur following rupture of the gastrointestinal or urinary tract.
Give an example where contrast can extend into a region it would not normally be visible without leakage occurring.
An example where contrast can extend into a region it would not normally be visible without leakage occurring is with a non-perforated gastrointestinal ulcer, where an ‘out-pouching’ of contrast into the stomach/duodenal wall may be seen on a barium series.
What should be done prior to any study of the gastrointestinal tract or the urinary tract?
Prior to any study of the gastrointestinal tract or the urinary tract (or when general anesthesia is necessary), the patient should be starved for at least 12 hours.
Why is chemical restraint contraindicated for some gastrointestinal studies?
Chemical restraint is contraindicated for some gastrointestinal studies because it can cause accidental aspiration of the contrast agent.
What are the three different phases observed in an intravenous urography (IVU) following the intravenous injection of contrast?
The three different phases observed in an intravenous urography (IVU) following the intravenous injection of contrast are: 1. Vascular phase, 2. Nephrogram phase, and 3. Pyelogram phase.
When performing an IVU to investigate for an ectopic ureter, what additional procedure should be performed first?
When performing an IVU to investigate for an ectopic ureter, a pneumocystogram should be performed first to highlight the termination of the ureters.
What are the two forms of interstitial lung pattern?
The two forms of interstitial lung pattern are unstructured interstitial pattern and nodular (or structured interstitial pattern).
How is atelectatic lung different from consolidated lung?
Atelectatic lung is reduced in size and the alveoli are empty and collapsed, while consolidated lung retains a normal size but the alveoli are replaced with fluid or cells instead of air.
Which lung lobe is affected in lung lobe torsion in deep-chested dogs? And in barrel-chested dogs?
In deep-chested dogs, lung lobe torsion affects the right middle lobe. In barrel-chested dogs, it affects the left cranial lobe.
What does an unstructured interstitial pattern in the lungs indicate?
An unstructured interstitial pattern in the lungs indicates a diffuse infiltration of the interstitium with fluid (oedema, exudate, haemorrhage) or cells (inflammatory, neoplastic fibrocytes).
What are some examples of alveolar patterns?
Some examples of alveolar patterns are pneumonia in a dog, cardiogenic oedema in a dog, and angiostrongylosis in a dog.
What causes an increase in opacity in the unstructured interstitial pattern?
An increase in opacity in the unstructured interstitial pattern is caused by a mild and often diffuse infiltration of the interstitium with fluid or cells.
What are some differentials for a diffuse opacification in the lungs?
Some differentials for diffuse opacification in the lungs are neoplasia (lymphoma, haemangiosarcoma, etc.), pneumonitis (viral, parasitic, etc.), disease in transition (onset of cardiogenic or non-cardiogenic pulmonary edema, pneumonia, etc.), pulmonary fibrosis (Westie), eosinophilic bronchopneumopathy (in conjunction with other signs), and artifactual causes (underexposed, underdeveloped radiographs, obesity).
What are some differentials for a localized opacification in the lungs?
Some differentials for localized opacification in the lungs are collapse/partial atelectasis, pulmonary thromboembolism, bronchial foreign body, and disease in transition.
What are the Roentgen signs used to describe a radiographic abnormality or lesion?
The Roentgen signs used to describe a radiographic abnormality or lesion are size, shape, location, number, margination, and opacity.
How is the overall size of an organ or structure identified on a radiograph?
The overall size of an organ or structure can be identified on a radiograph by comparing it to the size of an adjacent structure rather than based on its absolute dimension.
What are some structures often used as reference points to compare the size of organs on a radiograph?
Some structures often used as reference points to compare the size of organs on a radiograph are the intercostal spaces or vertebral body length for the cardiac silhouette, and the vertebral body length for the kidneys.
How can an increase in the size of an organ or structure that is not normally visible on a radiograph be identified?
An increase in the size of an organ or structure that is not normally visible on a radiograph can be identified when it becomes visible due to the increase in size.
What is the significance of shape in radiographic interpretation?
The shape of an organ can be altered by the presence of a lesion, enlargement of a chamber, or compression by an extrinsic lesion. Lesions within organs or structures should also be described in terms of their shape.
How can abnormalities of location be identified in radiographic imaging?
Abnormalities of location can be identified in radiographic imaging by having a good knowledge of normal anatomy and the relationships between organs. Confirmation often requires two orthogonal radiographic projections.
What are some potential causes for alterations in the position of a structure observed on a radiograph?
Alterations in the position of a structure observed on a radiograph can be caused by luxation of a joint, displacement of abdominal organs through a rupture, or other pathological conditions.
Why is it important to check the periphery of an image and the surrounding structures in radiographic interpretation?
It is important to check the periphery of an image and the surrounding structures in radiographic interpretation because lesions are commonly missed in these areas.
What is the main use of barium sulphate in diagnostic radiology?
The main use of barium sulphate is for imaging of the digestive system.
What happens when barium leaks into the peritoneal cavity?
If barium leaks into the peritoneal cavity, it can cause a severe granulomatous peritonitis, which can be life-threatening.
What is the most common risk associated with the use of barium?
The most common risk associated with the use of barium is the danger of an associated aspiration pneumonia.
How can barium aspiration be prevented?
The best way to prevent barium aspiration is to administer it via a stomach tube, and to use a cuffed endotracheal tube if the patient is under general anaesthesia.
What are the four categories of iodinated contrast agents based on their chemical structure?
The four categories of iodinated contrast agents are: 1. Ionic monomers (tri-iodinated), 2. Ionic dimers (hexa-iodinated), 3. Non-ionic monomers (tri-iodinated), 4. Non-ionic dimers (hexa-iodinated).
What is the difference between ionic monomeric agents and ionic dimeric agents?
Ionic monomeric agents contain sodium (increasing toxicity) or meglumine salts, while ionic dimeric agents have lower osmolarity than monomeric agents.
Why can’t ionic contrast agents be used for myelography?
Ionic contrast agents (monomeric or dimeric) cannot be used for myelography due to the increased risk of causing seizures.
Which type of iodinated contrast agents cause less side effects following intra-thecal injection?
Non-ionic monomeric agents cause less side effects following intra-thecal injection.
What is the benefit of using non-ionic dimeric iodinated contrast agents?
Non-ionic dimeric iodinated contrast agents have a lower osmolarity and are less toxic than ionic products.
How are non-ionic dimeric iodinated contrast agents excreted from the body?
Non-ionic dimeric iodinated contrast agents are excreted via the kidneys by glomerular filtration.
What are the organs most sensitive to systemic reactions caused by iodinated contrast agents?
The cardiovascular system, the kidneys, and the nervous system are the most sensitive organs to systemic reactions caused by iodinated contrast agents.
What is the main hemodynamic side-effect of iodinated contrast agents?
The main hemodynamic side-effect of iodinated contrast agents is vasodilation, which can lead to hypotension and tachycardia.
Why should iodinated contrast agents be avoided in patients with left-sided congestive heart failure?
Iodinated contrast agents should be avoided in patients with left-sided congestive heart failure due to the risk of causing hypotension and further compromising the cardiovascular system.
Which patients might have extra-renal excretion of iodinated contrast agents?
Patients with severe renal insufficiency might have extra-renal excretion of iodinated contrast agents, eliminated by the liver (in the bile).
What is the recommended type of iodinated contrast agent for myelography and similar procedures?
Only non-ionic iodinated contrast agents with low osmolarity should be used for myelography and similar procedures.
What is a common complication seen with myelography?
The most frequent complication seen with myelography is the occurrence of seizures when the patient recovers from general anesthesia.
What factors should be considered when determining the cause of left-sided cardiomegaly?
The breed, age, and size of the patient should be taken into consideration.
What are some diseases that commonly cause left-sided cardiomegaly in Cavalier King Charles Spaniels or Poodles?
Degenerative mitral valve disease is a common cause of left-sided cardiomegaly in these breeds.
In larger breeds of dogs, what is a more likely cause of left-sided cardiomegaly?
Dilated cardiomyopathy is more likely to be the cause in larger breeds of dogs.
What would be more likely as the cause of left-sided cardiomegaly in a puppy?
A congenital cardiac disease, such as patent ductus arteriosus, ventricular septal defect, or mitral valve dysplasia, would be more likely.
What would be more likely as the cause of left-sided cardiomegaly in an older dog?
Degenerative mitral valve disease or dilated cardiomyopathy would be more likely.
What are some possible further tests that may be needed to reach a final diagnosis?
Endoscopy, bronchoscopy, rhinoscopy, ultrasonography, CT, MRI, fluoroscopy, fine needle aspiration biopsy, needle core biopsy, surgical biopsy, blood tests, and surgery are possible further tests.
When is radiography most useful for examination?
Radiography is most useful for examination of the thorax.
What are the limitations of radiography?
Radiography is limited for examinations of the head and abdomen, as well as for examination of the spine without myelography.
Why should thoracic radiographs be taken in sternal recumbency prior to radiography?
Thoracic radiographs should be taken in sternal recumbency to avoid atelectasis.
What is the importance of taking radiographs quickly in thoracic imaging?
Radiographs should be taken quickly to reduce the amount of lung collapse that occurs between views.
In what respiratory phase should radiographs be taken to ensure optimum lung aeration?
Radiographs should be taken during peak inspiration to ensure optimum lung aeration.
What technique should be used to avoid blurring artifacts caused by respiratory motion?
A high kVP-low mAs technique should be used to avoid blurring artifacts caused by respiratory motion.
When should chemical restraint be used in thoracic radiography?
Chemical restraint should be used to prevent blurring artifacts caused by voluntary patient motion where appropriate and necessary.
What should be done with the thoracic limbs to prevent superimposition of brachial muscles with the cranial thorax?
The thoracic limbs should be pulled cranially to prevent superimposition of the brachial muscles with the cranial thorax.
What are the three structures that can be identified within the lungs on a normal radiograph?
The three structures that can be identified within the lungs on a normal radiograph are pulmonary arteries, pulmonary veins, and bronchial walls.
What is the location of cranial lobar pulmonary veins in relation to the pulmonary arteries on lateral views?
The cranial lobar pulmonary veins are located ventral to the pulmonary arteries on lateral views.
What are the radiographic features of a bronchial lung pattern?
The radiographic features of a bronchial lung pattern include increased visibility of bronchial walls, thickened bronchi referred to as ‘donuts’ when viewed end-on, and thickened bronchi referred to as ‘tramlines’ when viewed side-on.
What is peribronchial cuffing and what does it indicate?
Peribronchial cuffing is the infiltration of cells or fluid in the peribronchial space, which indicates interstitial disease.
What are the differentials for a bronchial lung pattern?
The differentials for a bronchial lung pattern include bronchitis, bronchopneumonia, eosinophilic bronchopneumopathy, and diffuse tumor.
What are the differentials for peribronchial cuffing?
The differentials for peribronchial cuffing include cardiogenic pulmonary edema, bronchopneumonia, and eosinophilic bronchopneumopathy.
What is an alveolar lung pattern?
An alveolar lung pattern is an increase in lung opacity caused by the replacement of gas in the alveoli with fluid or cells, or when the alveoli are collapsed and void of air.
What features are present in an alveolar lung pattern?
An alveolar lung pattern may have air bronchograms, a lobar sign, and increased lung opacity causing border effacement of soft tissue structures.
What are the differentials for an alveolar lung pattern?
The differentials for an alveolar lung pattern include atelectasis, pneumonia, cardiogenic edema, non-cardiogenic edema, hemorrhage, lung lobe torsion, pulmonary thromboembolism, and tumors.
What are some examples of conditions that can be under-estimated based on radiography alone?
Hyperparathyroidism, fractures or tumors, nasal tumors
Which radiographic projections are used to evaluate the nasal cavities and frontal sinuses?
Intra-oral dorsoventral and rostrocaudal projections, respectively
When is CT sometimes necessary for an accurate evaluation of nasal disorders?
When the lesions are extensive or there is invasion of the cribriform plate or orbit by tumors, or involvement of the frontal sinus with aspergillosis
How can certain nasopharyngeal disorders be detected on radiographs?
Sometimes on well-positioned lateral projections of the head
What types of ear diseases can sometimes be identified on radiographs?
Otitis externa and otitis media
What can cause destruction of the wall of the tympanic bulla, which may be identified on radiographs?
Some neoplastic processes, such as cholesteatoma
What can plain radiography demonstrate in the spine?
Severe bony lesions, such as tumors, displaced fractures, advanced discospondylitis, and degenerative changes
When do radiographic signs of discospondylitis become visible?
Around 2-3 weeks after the onset of the infection
Why is contrast radiography sometimes required during a radiographic study?
Because of the poor contrast resolution of plain radiography
What are some causes of mediastinal mass lesions?
The causes of mediastinal mass lesions can include neoplasia, cysts, abscesses, and granulomas.
What can radiography alone determine in cases of mediastinal mass lesions?
Radiography alone cannot differentiate between the different causes for a mass lesion.
What is a safe sampling method to identify pleural effusions?
Thoracocentesis and analysis of the pleural fluid is normally necessary.
What technique can be useful when dealing with smaller volumes of pleural fluid?
Ultrasonography can be useful to identify a safe sampling ‘window’.
What is a common use of radiography in patients with cardiac disease?
Radiography is used to identify and monitor left-sided congestive heart failure.
Why is radiography as the sole technique for imaging the abdomen not recommended?
Abdominal radiography has limitations, such as poor inherent contrast and inability to differentiate fluid from soft tissue.
What is an example of an abdominal organ enlargement that may be seen on radiographs?
Hepatomegaly (enlargement of the liver) can potentially be seen on a radiograph.
What further tests may be necessary to accurately determine the exact cause of an enlarged abdominal organ?
Ultrasound imaging is often necessary to accurately determine the cause of an enlarged abdominal organ.
What can cause a change in position of a structure?
The change in position may be secondary to the alteration in size and/or shape of an adjacent structure.
How can the position of a lesion affect the diagnosis or intervention?
The position of a lesion is important because it can strongly influence the diagnosis or subsequent intervention.
Why is it important to be familiar with the radiographic anatomy of each body region?
It is important to be familiar with the radiographic anatomy of each body region in order to avoid misinterpretation.
What is an example of a tubular soft tissue opacity structure located between the descending colon and the bladder in a female dog?
The presence of a tubular soft tissue opacity structure located between the descending colon and the bladder would favor enlargement of the uterus in a female dog.
How can the number of organs or tissues influence the differential diagnosis?
The presence or absence of a single lesion versus multiple lesions can influence the differential diagnosis.
What can influence the margin of a lesion?
The margins of a lesion can be well-defined or blurred/ill-defined. A lesion can also have a long or short transition zone with normal tissue.
What does an increase in opacity on an X-ray image usually indicate?
An increase in opacity is usually caused by the presence of an excessive amount of fluid or soft tissue, or by the presence of abnormal mineralizations.
What should be done once the entire radiograph has been evaluated?
A summary or list of the key findings/lesions should be compiled once the entire radiograph has been evaluated.
What are some examples of focal radiolucent lung lesions?
Some examples of focal radiolucent lung lesions are necrotic tumors, abscesses/granulomas, and gas-filled bullae.
How can radiography be useful for evaluating the thorax?
Radiography is a good technique for evaluating the thorax because it allows for the visualization of lung abnormalities.
What can make the interpretation of lungs difficult?
Various factors can make the interpretation of lungs difficult, such as the presence of overlapping structures or unclear findings on the radiograph.
What are the recommended imaging techniques if radiographs are inconclusive?
If radiographs are inconclusive, CT (Computed Tomography) and US (Ultrasound) can be useful for further evaluation.
