Exam 1 Flashcards
(61 cards)
Interpretative terms for various diagnostic Imaging modalities
Opacity
Anechoic
Hypoechoic
Hyperechoic
Sonolucent
Echogenic
Radiopharmaceutical uptake “uptake”
Attenuation
Signal intensity
Hyperintense
Hypointense
Isointense
Opacity:
relates to the amount of attenuation or x-ray absorption by the object. Attenuation causes an opaque area (bright or white) on a radiograph because absorbed photons do not reach the image plate. Depending on the ability of the object to absorb photons, various opacities can be distinguished.
-Air
-Fat
-Water (soft tissue)
-Bone
-Metal
Anechoic:
Black/dark, no echoes are returned to transducer
Hypoechoic:
Darker than surrounding or comparative structure (relative term)
Hyperechoic:
Brighter than surrounding or comparative structures (relative term)
Sonolucent:
General term for tissue that transmits sound to deeper structures
Echogenic:
General term for a tissue that reflects sound back to transducer. “Spleen has three hypoechoic nodules, and it is surrounded by anechoic fluid”
Radiopharmaceutical uptake “uptake” (Scintigraphy)
It can be decreased or increased compared to the expected normal. Areas of increased uptake are also called “hot” vs. “cold” terms usually kept out of reports.
Computed Tomography (CT)
Attenuation: it is a description of x-ray absorption rather than opacity or “density”
Hypoattenuation: decreased x-ray absorption compared to adjacent area. Dark, many photons reach the detector.
Hyperattenuation: Areas are bright, increased x-ray absorption. Few photons reach the detector.
MRI
Signal intensity: is the primary term used to describe the appearance of MR images
Hyperintense: implies an increased radio frequency signal that is returned from the tissues. Areas are bright
Hypointense: implies a decreased radio frequency signal is returned from the tissues. Areas are dark.
Isointense: implies two structures have the same signal intensity.
**Don’t use the term density to describe x-ray images”
How many views are the standard?
Why do we need three views of the thorax?
Three views
No excuse
15% of lesions will be missed if only one lateral view is made
Three views of the thorax because the lung on the lateral recumbency that is on the plate loses 50% of its volume. So it is under inflated.
Other views: ventrodorsal projection, right lateral projection, and left lateral projection.
Gravity causes the up areas to compress and remove the air of the bottom areas
-It is hard to separate the anatomy on the Hilum area from just one view.
-For example: case of labrador retriever with a splenic mass. The VD view shows the the soft tissue mass in the right lung. The right lateral view (against the plate, lung under inflated) shows the mass more dorsally oriented (radiopaque with the deflated lung), compared to the LEFT LATERAL view where the mass in BEST seen, radiolucent more contrast with the lung away from the plate.
How are right and left lateral views presented to the viewer?
They are both oriented with the head of the animal toward the left of the reader’s view.
-It is really important to flip it before the image is finalized.
VD and DV views Which one is better? does it matter?
Humanoid keeps scapula out of the lung field.
Regular VD is better
It does not matter as long positioning is good.
What are some common positioning errors ?
- Centering on diaphragm
- Elbow and triceps superimposed on thorax laterals
- Dropped sternum on laterals
- Axial rotation on ventrodorsal
How is the thorax approach divided?
Compartments
Lung
1. Interstitial
2. Alveolar
3. Bronchial
4. Vascular (also discuss with the heart)
Thoracic wall
Mediastinum
Pleural Space
Exposures for Digital Equipment
-Digital exposures are unique for each body/tissue
- kVp and mAs.
-Abdomen: kVp lower, mAs higher than thorax.
-Thorax: kVp higher, mAs lower than abdomen.
-Bone: kVp lower than abdomen and thorax, mAs higher than abdomen and thorax.
Exposure during Inspiration, when do we want to take a view? Why?
We only want to take a view during PEAK INSPIRATION
Variation between inspiration and expiration can cause alveolar pattern (false).
What are some aspects that affect normal appearance?
What is typical of the diaphragm on a left lateral view?
-Breed and species: big chested dogs more difficult to interpret
-BCS: fat makes it more challenging to see soft tissue
-Technique
-Expiration vs. Inspiration
-Interpreter bias
Left lateral view
-Diaphragm has a wide shape in dog.
-Aorta
-carina
-Trachea
-Caudal vena cava
-Left Cr. lobe vessels (shifted dorsally since it is a left lateral)
-Right Cr. lobe
-Xyphoid
-Caudal vena cava
-Cupula (dome)
-Diaphragm in cats has three humps (DV)
-Main stem bronchi
-Trachea better seen in lateral vies
-Cranial mediastinum
-Caudal lobar vessels easier to see in DV view than lateral view.
What are the anatomic names of the lung lobes? can you spot them on an image?
What is the Pattern approach interpretation?
Right lung is the largest
Trachea comes down and bifurcates at the Corina
-Left Cranial, Cranial lobe
-Left Cranial, caudal lobe
-Left Caudal lobe
-Right Cranial lobe
-Right Medial lobe
-Right Caudal lobe
-Accessory lobe: overlaps right middle and part of the right caudals.
Pattern approach: it encourages a systematic approach, use a checklist when you read. It assumes most diseases often affect a single compartment (wrong, limitation). Rule outs constructed for changes in each compartment. It helps prevent overlooking lesions. Can help ranked differentials.
-Mediastinum
-Pleural
-Alveolar
-Interstitial
-Vascular
-Bronchial
-Thoracic wall
Visual perception: fine detail is limited to a 2 cm circle. Need to look at the edges. VFR sweeps
Scan a radiograph completely before calling it normal
Bronchial compartment, what does it consist of?
-Lobar bronchi and bronchioles
-Normal bronchial components are not well seen in normalcy
-Bronchial markings are seen on radiographs as:
Ring and tramlines (pair lines shadows)
Increased rings and tramlines = “bronchial pattern” means that it is increased in marking.
-Bronchial wall in very thin
-Normal bronchial walls are thin shadows between lobar vessels and the bronchial lumen.
-As animal ages they become mineralized.
-Always read/interpret in context, metastasize check then it is different than just aging, or if animal is coughing
What do you usually see in a Bronchial pattern radiograph?
- Increased ring shadows
-Walls are thickened “doughnuts”
-They are too thick and too numerous to be normal
Lungs are really busy, not black DSH
Always look at the edges of the radiograph
-It is not easy to pick up bronchial patterns on a VD view.
-Bronchi can also dilate, not tapering. = BRONCHIECTASIS, predisposes to pneumonia.
What does bronchi mineralization look like? what is it similar too but often mistakenly diagnosed?
-Bronchial walls and bronchial glands may become mineralized a benign change that may be confused with cancer, metastasize.
Alveolar Compartment: the most difficult
do we normally see it?
What is the black areas normally seen?
What does it look like when diseased?
What does atelectasis refer to?
-They are not normally seen on radiographs
-Sponge, air spaces nor seen, the interstitial space is what is seen, everything else is microscopic.
-End air spaces are black normally
-The artery or vein is on either side of a bronchus, but appear white on a radiograph.
-Diseased alveoli looks opaque cells. The sponge absorbs fluid = “Fluid opacity”
Terms
-Atelectasis (same as collapse in this course): decreased inflation, less than at expiration, but still some air left in bronchial tree.
-Collapse: same as atelectasis
-Consolidation: normal volume or near to normal volume, alveoli, and bronchial tree filled with fluid or cells.
What are the three alveolar patterns?
- Air bronchogram: “air bronchiogram sign”
-Ex pneumonia, fluid filled clouds make the bronchi visible/contrast where they would otherwise be black. - Lobar opacity: “lobar sign”
- Focal intense opacity: usually center of lung
- Lobar opacity: “lobar sign” Consolidation & Atelectasis (collapse)
- Focal intense opacity: usually center of lung
-Normal lung contrast diseased lung.
-Due to segmentation of lung (lobation)
-Will not see it on horses or humans
Consolidation: also gives a Lobar sign. Animals not responding to tx.
Consolidation: small airways and alveoli filled radiopaque fluid or cells. Not air bronchogram, normal or decreased volume.
Atelectasis: little or no air in alveoli, LOBAR SIGN with LOW VOLUME. Common with COPD (disease in cats and dogs). The alveoli and bronchioles are flattened, small airways collapse, reduced lung volume. Can also cause an air bronchogram sign.
Labrador hit by a car: collapse due to tension pneumothorax.
What are the main differences between consolidation and atelectasis?
-Consolidation normal to near normal volume. No air bronchograms, alveoli and bronchioles filled with fluid or cells.
-Atelectasis: decreased volume, alveoli and bronchioles compressed but little to no fluid. air bronchograms if mild collapse, none if severe.
What are causes of alveolar pattern?
Pulmonary effacement, is it common, what is it?
- Pneumonia, bacterial, mycotic, aspiration
- Edema
- Hemorrhage/contusion
- Pneumothorax
- Lobbar torsion
- Neoplasia
Must be interpreted in the context of clinical presentation and signalment*
Pulmonary effacement
-Not common
-Usually early lesion, not bronchograms sign yet, but some disease present.
The pulmonary interstitium
The interstitial is the stroma or scaffolding of the lung. An interstitial pattern is ALWAYS present
Only see three things
1. Bronchioles: within interstitium
2. Air
3. Macroscopic blood and vessels.
False increased pulmonary interstitial pattern
-Due to under inflation: the most common false pattern
-Interstitial structures are surrounded by less air.
-Lateral views have more interstitial markings than ventrodorsal views
-Lungs look worse because of superimposition of both lungs.
What causes true unstructured interstitial pattern?
-Microscopic opacities scatter the x-ray beam
-Hazy and smudge image because the fluid or cells within the interstitial space
-Unsharp markings of normal structures
-similar to headlights in fog.
-Sometimes before disease progresses to pneumonia and presents alveolar pattern.
Structured More important to recognize than unstructured, peri bronchial markings.
Structured Interstitial Patterns
-Nodular and mass lesions
-Peri bronchial markings: discussed under bronchial patterns.
Nodular interstitial lesions
- Solid: soft tissue or mineral/bone: the most common type. Bullae or cyst
- Cavitary: Gas filled, Gas filled and fluid filled.
Must be at least 4-5 mm for detection
-air filled - black, with thin radiopaque wall. Thick wall if fluid filled and air.
Example: cystic areas in the lung from parasites such as Paragonimiasis. End on vessel: Dirofilariasis.
Prime differentials of nodular disease
-Neoplasia: metastatic most common. Primary: can be benign lesions. Coalescing nodules.
-Mycosis: Blastomycosis (can look like bacterial pneumonia), Histoplasmosis (thoracic nodules, nodules).
Appendix
Positioning: what are the common mistakes? what are the landmarks? what is dropped sternum?
-Center the thorax, not the diaphragm
-Landmarks: Manubrium/1st pair rib
-Last rib
-Thorax and abdomen combined are of no advantage, decrease image quality.
-Superimposition of triceps musculature: dependent limb in beam
-Dropped sternum: spine not aligned, sternum out of image., causes lack of visualization of all lungs.
-Oblique positions: limit assessment of lungs and shape of the heart. Spinous processes are tipped to right or left which causes the sternum to be tipped to the opposite side of midline.
-Overexposure/underexposure.
Lung Cases
- Chronic case of coughing Labrador retriever
-Several round structures that look like donuts.
-Too busy area.
-Bronchitis is not a radiographic diagnosis
-Increased mucus is not seen in radiographs. - siamese with coughing episodes (very common)
-Lots of rain shadows
-Looks like strictly in lung compartment not interstitium
-Numerous lines and rings.
-Bronchoconstriction makes it hard for cat to get the air out
-FLAD: feline lower airway disease NOT ASTHMA term
Radiographic changes:
-From none to severe
-Hyperinflation = bronchoconstriction
-Bronchial pattern = relapsing insults
-Cor pulmonale = pulmonary hypertension
-Collapsed right middle lobe = increased intrathoracic pressure
-Emphysema = increased end airspace pressure
-It can be acute or chronic
-Chronic: hazy
-Hard to tell in a radiograph, need CT
-Cats have more lung capacity than dogs.
-Heart is more horizontal
-Spinous process larger than dogs’
-Tenting of the diaphragm normal during peak inspiration (pic).
What often occurs in cats with FLAD? hint: right middle lobe
What is the substitute term for bronchitis? what does it include?
-Due to increased intrathoracic pressure and or bronchiolar obstruction = Atelectic.
-They tend to not get better, can go on, just lose one lobe.
Small Airway Disease
-Includes bronchioles, terminal bronchioles and alveolar ducts.
-Interstitium also involved
-Only see bronchi and 1st-3rd order bronchioles on most radiographs.
-Flattened diaphragm means struggling to get rid of air.
