Diagnostic imaging - the thorax Flashcards

Question

Identify this pathology and describe its significance ? (red arrow)

Answer 1

Pleural fissure lines on a VD view indicates a small degree of pleural effusion

Answer 2

Effacement occurs when to structures of the same opacity are in contact with each other. Neither structure can be distinguished from the other.

Answer 3

Three reasons of increased opacity in the thorax 1. Pleural effusion 2. Alveoli lung pattern 3. Mass - lung, cranial mediastinal, rib

Answer 4

Pneumothorax (best view to assess is on the lateral views) Pneumothorax identification - seperation of the heart from sternum - retraction of the lungs from the thoracic wall Pathology pneumothorax - trauma rupture of the lung - trauma defect in the wall of the thorax - sponatnaeous - rupture of lung bulla, migrating grass seed

Answer 5

False pneumothorax Skin fold artefact appears alike to pneumothorax 'false pneumothorax' Skin folds are frequently seen in radiographs but the skin fold will continue out side the thorax. - additionally can not be observed in both views eg lateral and VD

Answer 6

**Tension pneumothorax** Identify Mediastinal shift of the heart away from the pneumothorax (due to increased presse in the affected side. Why is it important - check valve mechanism letting air in but not out - pressure in pleural space increases above atmospheric pressure - life threatening condition - immediately drain. **Non-tension pneumothorax** - usually no mediastinal shift - there may be a mediastinal shift of the heart towards the pneumothorax (due to collapse of the lungs on the affected side) - atelectasis

Answer 7

Red = aorta Green = caudal vena cava On the VD view you can only view the left side of the aorta as its effaces with the soft tissues of the mediastinum.

Answer 8

Pathology of the vena cava If vena cava >1.5 x the aorta on the lateral view - subjective identification of dilation on the lateral view - care with describing the vena cava as dilated as it changes naturally with cardiac ryhthm Causes - right sided heart failure - small CVC part of general hypovascularity

Answer 9

Pulmonary artery and vein (if struggling first identify the bronchus which bifurcates at the fifth vertebrae). Pulmonary artery = red arrow Pulmonary vein = blue arrow Bronchus = green arrow Artery - bronchus - vein = ABV veins are ventral and central

Answer 10

The two test pulmonary artery and vein (they must pass both tests) Test one - are the PA and PV the same width Test two - LATERAL VIEW = PA and PV width where the 4th ribs cross them, must be < 3/4 of the thickest rib width close to the spine. - VD VIEW = PA and PV where the 9th rib cross them should be <3/4 of the width of the rib

Answer 11

PA and PV lateral projection (first assess test one are they the same width) 1. Assess the width of the vessels at the level where the fourth rib crosses them 2. compare to the thickest part of the fourth rib at the level of the vertebrae The vessels should be <3/4 of the width of the rib Remember pick the lateral view in which the vessels are most visible

Answer 12

PA and PV VD view (did they pass test one) 1. Assess width of PA and PV at the level at which they intersect rib nine 2. the width of the vessels should be < 3/4 the width of the rib.

Answer 13

PA and PV abnormalities 1. Both are small 2. Both are large 3. PA is large 4. PV is small

Answer 14

PA and PV too small Hypovascular lung pattern Blood loss Shock Dehydration Addisons

Answer 15

Dilated PA and PV Pathology - Patent ductus arteriosus (PDA) - Fluid overload - Left sided heart disease ( potentially with secondary pulmonary hypertension)

Answer 16

Large PA (dilated) Pathology - heart worm disease - pulmonary hypertension (chronic lung disease, secondary left sided heart failure)

Answer 17

PV large Pathology - left sided heart failure - usually mitral valve disease in small dogs and DCM in large breeds

Answer 18

Heart assessment There are four rules Three test for the size of the heart - 2/3 assessment on lateral and Vd view - intercostal space assessment 2.5-3.5 dogs, cats 2 - vertebral heart score Heart shape The only abnormalities which can be accurately assessed are the left atrium and main pulmonary artery MPA.

Answer 19

2/3 assessment of the heart - Do the 2/3 assessment on the lateral and VD - The heart is 2/3 of the height and width of the thorax (cat is more like 50% on the VD). remember to angle with length of heart

Answer 20

Measure intercostal length on the lateral view Measure across the thickest section of the heart. dog = 2.5 - 3.5 intercostal spaces cat = 2 intercostal spaces To assess for rotation the intercostal junctions need to be all at the same level. - find cranial rib of pair + count from cranial rib to cranial rib

Answer 21

Vertebral heart score objective - does not replace subjective assessment - not reliable in cats (use size + shape in cats) - useful for a fast comparison over time

Answer 22

Vetebral left atrial size (VLAS) measure from the ventral aspect of the carina to the junction between CVC and heart Normal = is upto 2.3 vertebrae

Answer 23

The only two structures which can be accurately assessed main pulmonary artery clock 1-2 Left atrium remember radiography is not accurate for right side enlargement.

Answer 24

Small dog mitral valve disease (usually older small dog) Degeneration of the mitral valve - causes regurgitation so blood flows back into the LA causing it to dilate - left side apical heart murmur, the severeity of murmur correlates to the severeity of disease - left sided heart failure

Answer 25

Mitral valve disease (usually older small dog + murmur + dyspnoea) radiograph or echocardiograph to determine dilation of the left ventricle - if normal repeat six months later - monitor resting respiratory disease ( complete radiographs to identify pulmonary odema and thus heart failure.)

Answer 26

Dilated cardiomyopathy (DCM) Large bred older dog - dilated LA and LV reduced contractility - may be observed as a large heart - pulmonary oedema heart failure; caudal lung lobes - can be left right or both (right sided heart failure less common) - pulmonary oedema is usually more patchy than in mitral valve disease

Answer 27

Dilated cardiomyopathy - large dog Echocardiography is required to diagnose DCM, all dogs suspected should have a echocardiogram - DCM is much more serious and they die sooner - medications are expensive so diagnoses is needed - CS are not as obvious Radiographs used to identify pulmonary oedema

Answer 28

Right sided heart failure (pleural effusion and / or ascites) Right sided heart failure and pericardial effusion - pleural effusion and or ascites - most common cause of pericardial effusion - pleural effusion can be detected on TFAST - ascites on AFAST - radiology is inaccurate never diagnose right sided heart failure on radiographs alone (must take it back to the animal) Causes - heart worm disease - test HW - pulmonic stenosis, tricusid dysplasia - is a murmur present - pulmonary hypertension - is there lung disease echo Echocardiography to look for a right atrial mass causing the pericardial effusion.

Answer 29

Pericardial effusion Diagnose - TFAST - cardiomegaly Many dogs with pericardial effusion do not have detectable pericardial effusion on radiographs.

Answer 30

PPDH Pertoneal pericardial Diaphragmatic Hernia Radiograph - enlarged cardiac silhouette - diaphragm margin not seen ( - small liver - the clinical signs do not fit with severe heart disease

Answer 31

Hypertrophic cardiomyopathy (HCM) 70% of cardiac disease in cats - cardiomegaly (normal heart may appear in 10% of cats) - the heart appears normal but has become thicker on the inside 'hypertrophy' - pleural effusion is common Heart failure is the most common cause of pleural effusion in cats.

Answer 32

Hypertrophic cardiomyopathy (HCM) - The heart in a healthy cat should appear as an almond - HCM heart =peanut or valantine heart - or generalised enlargement (no longer almond shaped) - pulmonary oedema - patchy interstitual lung pattern Should diagnose with echocardiography as CS are often subtle and cats may present with failure with no warning TFAST pleural effusion Radiography = pulmonary oedema

Answer 33

Pathology is best observed in the aerated upper lung The uppermost lobes contain the most air to contrast against soft tissue opacity.

Answer 34

The test for lung pattern 1. Bronchial 2. Alveolar 3. Interstitual - patchy area of interstitual lung pattern - structured interstitual lung pattern nodules/masses - diffuse unstructured interstitual lung pattern

Answer 35

Bronchial lung pattern Best identified by - donuts end on bronchi - tram tracks (thickened bronchial walls) The wall of the bronchi are not normally seen Donuts are easier to see than tram tracks, so just look for donuts.

Answer 36

Bronchial lung pattern pathology Dogs - infection bronchial - bacterial, lungworm, heart worm - chronic bronchitis - old small breed (50% have normal lungs - eosinophilic bronchopneumopathy Cats - feline bronchial asthma (most common by far) - lungworm - Aleurostrongylus abstructus

Answer 37

Bronchial cuffing The bronchi are normal but appear thickened - interstitual lung pattern increases opacity around the bronchus - can not differentiate radiographically from a bronchial pattern Note - many patients look like they could have a mild bronchial lung pattern - if the patient has no CS it is likely normal.

Answer 38

Alveolar lung patter The black background becomes white Abnormal lung - filling of the alveolar air space with fluid or cells, which displaces the air with soft tissue opacity. Alveoli lung pattern signs 1. increased lung opacity - white lung 2. Effacement - heart, diaphragm, blood vessels 3. Air bronchograms 4. Lobar sign

Answer 39

Increased lung opacity = white lung - may be the only sign of alveolar lung pattern - seen every time, may be the only sign - there are other causes of increased soft tissue opacity (eg pleural effusion, mass).

Answer 40

Effacement Inability to distinguish different organ from each other. ( same opacity and contact). Effacement of the heart or diaphragm is the easiest sign to recognise. (alveolar lung pattern). - effacement of vessels - not always seen (the alveolar lung pattern must be in contact with the effeced organ) - may also occur with masses, pleural effusion

Answer 41

Lung lobe = Left cranial-caudal

Answer 42

Pleural effusion = retraction of the lungs + vessels remain visible Alveolar lung pattern = no vessels are seen as they are effaced with the lung fluid

Answer 43

Air bronchogram This is a normal bronchus seen against a white lung - pathognomic for alveoli lung pattern - not seen every time Often mistaken with normal bronchi - key are the PA and PV visible either side of the bronchus (not visible air bronchogram)

Answer 44

Green = normal Blue = bronchial lung pattern Yellow = Alveolar lung pattern

Answer 45

Lobar border pathoneumonic alveolar lung pattern Abnormal white lung next to normal black lung - border of lung is hence vsiible - not seen every time - to recognise you need to know the location of the lung borders.

Answer 46

Alveolar pattern causes (what things fill the alveoli) There are five 1. Pus - pneumonia 2. Water - oedema 3. Blood - haemorrhage, contusion 4. Cells - neoplasia (less common eg carcinoma) 5. Atelectasis (collapse) no air in the alveoli

Answer 47

Pneumonia cranial and middle lung lobes ventral parts Pneumonia takes three days before any improvement following treatment

Answer 48

Oedema - caudal lung lobes - cardiogeni, often the right caudal is the first and worst affected - non cardiogenic the caudal lung lobes are symmetrically affected and no signs of heart disease. Will show big improvement with tx (frusemide) 6 - 12 hours

Answer 49

Haemorrhage - anywhere - coagulopathy or pulmonary contusion trauma Neoplasia - anywhere - pulmonary carcinoma, can be a mass, mulifocal or lobar - histiocytic sarcoma usually lobar neoplasia

Answer 50

Interstiual lung pattern A patch or areas/s of interstitual lung pattern not severe enough to be alveolar The margins of heart and blood vessels may be hazy but can be identified. - increased soft tissue opacity - no effacement - no lobar border - no air bronchogram

Answer 51

Interstitual lung pattern Pathology - pneumonia - odema - neoplasia - haemorrhage - the same as an alveoli lung pattern but to a reduced degree

Answer 52

Diffuse unstructured lung pattern There is increased opacity (diffuse) affecting all the lung and homogenous - not patchy Most difficult pathology to recognise - artefact (most common by far) - underinflation - fat dog - normal for age - lymphoma - pulmonary fibrosis " interstitual lung disease" - pneumonia viral fungal or bacterial For brachycephalic or barrel chested dogs the lungs are best assessed on the VD view.

Answer 53

Structured interstitial lung pattern This is identified by observing - single mass - multiple nodules - miliary nodular - lots of small nodules Neoplasia is the most common cause for them all

Answer 54

Nodule < 2cm Mass > 2cm the smallest nodule that can be seen = 3mm Why is this important - differentials If observed small than three mm we know probability - end on blood vessel - pulmonary osteomas - thoracic wall

Answer 55

Miliary nodular Structured interstitual lung pattern haemangiosarcoma

Answer 56

Multiple nodules Structured interstitual lung pattern pulmonary metastases

Answer 57

Metastasis check - Met check 3 views minimum - right lateral - left lateral - VD - often most visible over the heart and diaphragm (due to summation) - care diagnosing over a rib

Answer 58

Shoulder and elbow pain differentials young dog The should can not be assessed for pain without also loading the elbow joint - it is difficult to isolate the pain - usually rad both the shoulders and elbow Differentials - osteochondrosis - ununtied anconeal process (UAP) - fragmented coronoid process - osteoarthritis - panosteitis - incomplete ossification of humeral condyle (IOHC) - fractures The most common cause of shoulder pain in a young large breed dog is osteochondrosis, so just one lateral view is required.

Answer 59

Two standard views of the shoulder Craniocaudal Lateral view Only exception - young large breed only requires a lateral view (Osteochondrosis)

Answer 60

Shoulder osteoarthritis osteophyte within the shoulder joint.

Answer 61

Shoulder osteochondrosis most commonly affected joint.

Answer 62

Humerus - one condyle, with two articular parts; trochlea / ulna and Capitulum / radius - most weight bearing is through the radial articulation -medial and lateral epicondyles ridge is seen on the lateral view

Answer 63

This is not a pathology Elbow seasamoid bone which is present in 1/3 of all dogs.

Answer 64

Supracondyloid foramen

Answer 65

Elbow dysplasia (young large breed dog) Exclusively a term used for young dogs, once the dog >2yrs of age we refer to it as elbow osteoarthritis (OA) - in a young large breed dog with elbow pain, it is always due to elbow dysplasia until proven otherwise. - difficult to distinguish shoulder and elbow pain Differentials - Ununited anconeal process (UAP) - Osteochondrosis (OC) - Fragmented medial coronoid process (FCP)

Answer 66

Ununited anconeal process (UAP) Young large breed dog Some large breed puppies have a normal accessory centre of ossification in the anconeal process. - it closes 20-22 weeks - if it remains open byond this it becomes 'ununited'

Answer 67

Osteochondrosis (OC) In the medial part of the humeral condyle only - assess this specific location.

Answer 68

Osteoarthritis Enthesophytes and osteophytes - in a young large breed may be supportive of FCP

Answer 69

FCP = fragmented medial coronoid process (young large breed dog) - the most common cause of elbow dysplasia - the fragment is usually not visable on radiograph (due to superimposition) - requires CT and arthroscopy in combination for a definitive diagnosis. If these are not available a diagnosis may be made through elimination - of UAP and elbow OC and shoulder OC are ruled out.

Answer 70

Incomplete ossification of the humeral condyle (IOHC) The growth centre in the humeral condyle fails to close / ossify Pathology The humerus has one condyle, which has two parts medial and lateral - the normal growth centre between the medial and lateral condyle closes at two weeks and is complete by 8-12 weeks - hereditary condition - allow upto 6 months for individual variation before calling it 'incomplete ossification'

Answer 71

Incomplete ossification of the humeral condyle ( not closed beyond six month of age) Signalment - french bulldog, spaniel cross - can however occur in any breed - age - can present at any age but 55% < 1 yo - male > female Clinical signs - lameness can be caused by the IOHC itself (no fracture) - pathological fracture with minimal trauma eg jumping

Answer 72

Incomplete ossification of the humeral condyle (IOHC) Allow for individual variation, only consider pathology beyond six months of age. - For diagnosis ensure the centre of the olecranon is over the mid condyle - radiography is 83% sensitive but only if you remember this.

Answer 73

Radiography of the pelvis. Standard view - extended VD of the pelvis - include stifles and top of the ileum of the hip - use for assessment of hip dysplasia Frogleg view - additional view for the assessment of trauma - pelvis fracture + slipped capital physis Lateral view - not required for hip dysplasia assessment - important for assessment of trauma

Answer 74

Hip dysplasia Signalment - large breed dogs Pathology Developmental disease, the hips are normal at birth -joint laxity (subluxation) is the earliest signs and the hallmark of hip dysplasia caused by a combination of nutrition and environmental factors - usually bilateral

Answer 75

Hip dysplasia - there are two parts 1. Subluxation - joint laxity (hip dysplasia) 2. Osteoarthritis (OA) This is caused by joint laxity. It is usually present by 1yo, so may be missed on radiograpgh at the time of diagnosis as it takes time to develop.

Answer 76

Hip osteoarthritis (OA) Remember hip dysplasia = young dogs, where OA is older animals >4yrs Many older cats and dogs have osteoarthritis - could be due to aging - due to hip dysplasia when they were young - avascular necrosis of the femoral head Many tolerate hip OA very well and do not show signs of lameness (Be aware signs of osteoarthritis may not be the cause of lameness in an older animal).

Answer 77

Hip dysplasia (Two parts osteoarthritis and luxation) Identify on radiograpgh by - extended VD view - find edge of acetabulum - find the centre of the femoral head - the centre of the femoral head should be inside the acetabulum

Answer 78

Morgans line Enthesophyte along the attachment of the joint capsule on the neck of the femur - it can be a normal finding - earliest sign of osteoarthritis

Answer 79

Osteoarthritis There are four major signs of osteoarthritis 1. Morgans line, enthesiophyte 2. Ring of osteophytes around the femoral head - (periarticular) 3. Remodelling - Change in the shape of the femoral head and neck (flatter head and thicker neck) 4. Acetabulum - Osteophytes on the cranial aspect, remodelling change in shape, so that it is wider and shallower

Answer 80

Exam practice - subluxation eveident right hip - morgans line left hip

Answer 81

Feline hip dysplasia Not very common - OA only affects the acetabulum

Answer 82

Quality extended view of the pelvis - collimate to include wings of the ilium and stifle joint - patella in the centre centre - obturator foramen must be symetric

Answer 83

Exam question two - the ileum is not symetrical - the obturator formamen is not symetrical this indicates rotation

Answer 84

Certification schemes for hip dysplasia CHEDS PennHIP The breed - reduce incidence Individual - managemnt of an individual

Answer 85

Certification schemes for hip dysplasia Cheds - extended VD view - mostly assess for OA which occurs later - may not select out dogs prior to breeding - 20 years of use in Australia PennHIP - uses distraction view - sensitive for subluxation - high heritability - can detect hip dysplasia in young dogs - requires restraint of animal by hand = radiation exposure

Answer 86

Avascular necrosis of the Femoral head Signalment - small breeds, especially terriers - usually young dogs (5-12 months old) - usually unilateral Pathology Ischeamia - causing necrosis and collapse + deformity of the femoral head - inherited disease

Answer 87

Avascular necrosis of the femoral head (Legg calve Perthes disease) Radiographic signs - usually unilateral (compare other limb) - lucent areas (loss due to bone necrosis) - femoral head collapses (smaller) Chronic cases in older dogs will also have unilateral OA, possible due to avascular necrosis of the femoral head when they were young.

Answer 88

Capital physeal fracture / slipped capital physis Signalment - more common in cats as they have delayed physeal closure (so can occur in adult cats) - cats may be atraumatic due to delayed closure - male possible overweight + desexed early Radiographic signs - Salter Harris fracture one

Answer 89

Metaphyseal osteopathy (apple coring) Cats - Bone lysis of the femoral necks (apple core) - often seen with capital physeal fracture - young, often male, often bilateral 2 causes - apple coring seconda after atraumatic captital physeal fracture - apple coring occurs first. It may cause a capital physeal fracture - delayed physical closure is often seen with it

Answer 90

Sacroiliac joint sublaxation Use an extended VD view - inhealth there is a smooth junction across the sacroiliac joint - with sublaxation there is a divet Never use the joint space of the sacroiliac joint, as this may appear enlarged with mild rotation.

Answer 91

Sacro iliac joint sublaxation

Answer 92

Crucial ligament disease (CCL)

Answer 93

Cruciate ligament disease (CCL) This is the most common cause of lameness in the stifle - diagnose by cranial drawer sign (joint instability) - may not be present if the rupture is partial - but if there is often evidence of joint effusion on radiographsbefore cranial drawer sign - joint effusion is only visible on the lateral view - usually also OA, but not if acute Surgery is based off clinical signs/examination + joint effusion - therefore it is absolutely essential that the lateral projection is perfect.

Answer 94

Signs of osteoarthritis Periarticular osteophytes Enthesophytes + / - joint effusion The common location of pathology - Trochlear ridges - Patella - CCL insertion - Fabellae

Answer 95

Quality radiograph of the stifle Lateral view - peeing pose + belly tape (prevent the belly being superimposed on the stifle - degree of flexion must be the same as standing (allows examination of the caudal aspect of the joint). - condyles need to be superimposed, place a foam pad under the hip to rotate stifle down Summary 1. One leg on the view 2. Not superimposed on the abdomen 3. Degree of flexion - same as standing 4. Femoral condyles superimposed 5. centre on the joint

Answer 96

Craniocaudal view of the stifle 1. patella in the centre of the femur 2. Fabellae centered on the cortices of the femur Remember it is ok to assess the stifle CC views on the extended VD of the hips if they are perfectly positioned. (less important to assess stifle effusion)

Answer 97

Medial petalla luxation Best diagnosed through palpation - may use radiographs to assess for concurrent disease - often missed on radiograph as luxation is positional in most cases - additional congenital limb deformity can appear as a luxation on radiograph

Answer 98

Tibial tuberosity avulsion - always radiograpthe other leg - 4-8 months old - non traumatic - the petella ligament attaches to the tibial tuberosity and strong contraction of the quadraceps muscles can pull it off.

Answer 99

Aggressive joint lesions (lysis and perisoteal new bone) Aggressive digit lesions are more common in dogs than cats Common causes - soft tissue neoplasm (soft tissue sarcoma) - osteomyelitis (nail bed infection) - cats 20% 'lung digit syndrome' secondary neoplasia The cause can not be determined via radiograph. - fine needle aspirate , amputate or histology - thorax radiographs

Answer 100

Lung digit syndrome in cats Primary lung neoplasia with metastases to the digits - often present with digit lesion first - radiograph the thorax for primary neoplasm Poor prognosis. Don't amputate the digits, as other lesions quickly occur in the remaining digits.

Answer 101

Stress radiography (instability of the carpus and tarsus due to trauma) Joint instability can be determined by physical examination So stress radiograps are taken too - assess for fractures - document the instability for referral surgery - always radiograph the normal leg too

Answer 102

Osteochondrosis In the tarsus appears as just a wider joint space medial ridge of the talus is most often affected

Answer 103

Tracheal membrane large bred dog. Large breed dog with no cough - this is likely just normal superimposition of the oesophagus as tracheal collapse is very rare in lrage breed dogs. If we observe a tracheal membrane and chronic cough in a small dog - it may indicate tracheal collapse - requires further testing through endoscopy or fluroscopy.

Answer 104

The width of the cranial mediastinum is increased. (must be assessed VD) >2 x the vertebrae width - tip; if the cranial mediastinum is wide go to the lateral view to work out what structure is abnormal.

Answer 105

Cardiac failure in cats Pulmonary oedema - interstitual or alveolar lung pattern - assess on radiographs Pleural effusion - pleural fissue lines, lung retraction and lung leafing - confirm via TFAST

Diagnostic imaging - the thorax Flashcards

The thorax (136 cards)