Thorax Review and Revitalize

Transcription

1 Outline Thorax Review and Revitalize Anatomy Sarah Tibbs, BVetMed, DACVR April 2016 I will try to share little Tibbits along the way (Tibbs Tidbits) Patterns Review like students Lungs Pleura Heart Other structures Dependency effects Importance of thoracic radiographs Thoracic radiographs are one of the most common diagnostics performed They can be used to evaluate for normalcy and pathology They are critical in diagnosing Heart failure Lung lobe torsion Pneumonia Metastatic cancer etc. Understanding anatomy and variability in anatomy is critical to determine if something is pathology or not Patterns be crazy Breeds be crazy Anatomy 101 Review like students Alveolar Interstitial Bronchial DDX Lungs Right Cranial Middle Caudal Accessory Left Cranial Caudal Left Lateral - see the right lungs

2 VD (DV) view Anatomy 101 Right Lateral - see the left lungs Lungs Right Cranial Middle Caudal Accessory Left Cranial Caudal Anatomy 101 Lungs Right Cranial Middle Caudal Accessory Left Cranial Caudal VD (DV) view Anatomy 101 Pleura There are two layers of pleura that wrap the lungs and the inner walls of the thorax A thin potential lubricated space between them The spaces between the lung lobe are called fissures These expand when either gas or fluid is present VD (DV) view Anatomy 101

3 VD (DV) view Anatomy 101 Mediastinal masses Mediastinum The space between the two halves of pleura that contains the heart and other centrally located structures in the thorax The pleural halves are connected by a fenestrated mediastinum Right Lucky for us Anatomy of cat lungs are like little dog lungs Left Unlike all other cat things AND especially..cat lung pathology These masses can sometimes be poorly defined, faint soft tissue structures on the lateral view, despite being very distinct on the VD view

4 Anatomy Heart anatomy Anatomy 101 y te ar Tick tock..time for the clock 12 A Rig ht a aortic arch main pulmonary artery left auricular appendage left ventricle right ventricle right atrium Get bumps when these things get enlarged triu m 9 ic ntr ft ve m l pu ve nt 6 on ric le Anatomy 101 ry ge a nd e pp ra a 1 ain ul ric M 2 t au f Le 3 Le le t igh R ar ta or Cranial cardiac waist a. Right atrium b. Main pulmonary artery c. Aortic arch Caudal cardiac waist a. Left atrium i. Pushes the carina dorsally Right ventricle a. Increased width of heart and sternal overlay b. Severe enlargement can displace the apex of the heart dorsally Left ventricle a. Increased the height of the heart/displaced carina dorsally Hang on what about the left atrium Behind the carina Bows the cowboy legs

5 Vertebral Heart Score Cat heart T4 Other things we can see Trachea Carina Cranial lobar vessels and bronchus MIddle lobar vessels and bronchus Caudal lobar vessels and bronchus Caudal vena cava Aorta Diaphragmatic line Objective way to measure the heart and account for patient size variability Place a line from ventral carina to apex of heart Place a line across widest part of heart About 90 degrees from first line At about the level of the caudal vena cava Compare to vertebral length starting at T4 Normal Almond shape and 2 ICS On the lateral view generalized enlargement is seen More than 2 ICS shaped more like a potato While on the VD view, the most common enlargement seen in biatrial - valentine heart Other things we can see Trachea Mediastinum Carina Cranial lobar vessels and bronchus MIddle lobar vessels and bronchus Caudal lobar vessels and bronchus Caudal vena cava Aorta Diaphragmatic line Caudal pleural reflection

6 Things we can t see Esophagus Thymus Mediastinal lymph nodes Sternal lymph nodes Tracheobronchial lymph nodes Things we can t see Esophagus Thymus Mediastinal lymph nodes Tracheobronchial lymph nodes Positions So that s anatomy, however, anatomy is affected by body position/projection Right Lateral Left Lateral VD DV Heart Shape Oval Round Longer apex to left Rounder Diaphragm Parallel V shaped 3 humps 1 hump Caudal vena cava Direct into diaphragm Over diaphragm Always hangs out on right side going into caval hiatus

7 Positions Why take variable positioned thoracic rads Right Lateral Left Lateral VD DV Heart Shape Oval Round Longer apex to left Rounder Diaphragm Parallel V shaped 3 humps 1 hump Caudal vena cava Direct into diaphragm Over diaphragm Left versus right Only evaluating inflated lung (the up side) DV versus VD 3 views are considered necessary for evaluation for metastatic disease Always hangs out on right side going into caval hiatus i.e. - right middle lung lobe pneumonia can hide on a right lateral view when looking at left lungs (ex to follow) Caudal lobar vessels are more pronounced on the DV (also caudal dorsal masses) Often decided by other factors as well - patient status, compliance or external lesions So that's anatomy and body position/projection effects... Right lateral Left lateral

8 But the designers of dogs seem to have a sense of humor Normal Brachycephalic What the? Normal French Bulldog French Bulldog

9 Normal English Bulldog Normal Normal English Bulldog Normal Pug Boston Terrier

10 Holy ventral spondylosis batman In brachycephalic dogs Watch out for. Normal wide cranial mediastinum Overall shortened thorax Greater lordosis in the cranial thoracic spine Wacky vertebral body shape Tweeny tracheas (a ratio can be done to determine if hypoplasia is present) Overall more interstitial pattern Often normal Sometimes from panting during imaging Sometimes from chronic airway inflammation Sometimes from real pathology Chondrodystrophic Long and not always lean Corgi

11 In chondrodystrophic dogs Watch out for. Longer thorax length Wavy lines along the lateral aspects of the thorax from rib conformation Obliquity can really make the sternum/ventral aspect of the thorax look weird from superimposed lines Schnauzers What is that? Some other funky shaped breeds

12 Min Pins Real Pins

13 If you make your dog compact and square on the outside it heart will take up more space on the inside Oh, and cats - mostly look the same but sometimes we make them look funny because they are bendy

14 But sometime they really are bent Patterns Why care about patterns Patterns help us create differentials Along with distribution Pattern recognition does not equal disease recognition Lungs can only respond in limited ways What lobes/how many Where in lobe(s) Symmetry Loss of air space - replaced by fluid and/or cells Increased fluid or cells in the interstitium Thickening of the airway walls Therefore pathologies overlap Lung patterns Remember the pattern name tells you where the disease is: Alveolar Interstitial Bronchial Alveolar is usually considered the most severe form of lung pattern given that is represent loss of airspace Mixed patterns are common, attempts should be made to describe the most severe form present

15 Alveolar pattern Interstitial pattern Patterns 2. Alveolar Pattern Border effacement/silhouette sign Lobar signs Air bronchograms Bronchial Pattern Interstitial Patterns 1. Bronchial pattern Unstructured a. Hazy b. Indistinct without effacement Structured a. Nodules i. Cannonball ii. Small iii. Hazy Doughnuts (or bagels if you prefer) Tram/Train lines Bronchiectasis

16 Okay, so that makes patterns seem real easy and straightforward Young versus old dog Insert maniacal laugh..not so in real life

17 Young versus old dog Young versus old cat Fat versus thin Dog Young versus old

18 Fat versus thin Dog Fat versus thin cat Alveolar Pattern Okay, so let s look at some real life pattern examples Border effacement/silhouette sign Lobar signs Air bronchograms

19 Alveolar in cats Alveolar So when interstitial is not quite alveolar and alveolar is not quite interstitial Mixed pattern Patchy alveolar Air aveolograms

20 Interstitial Patterns Unstructured a. Hazy b. Indistinct without effacement Structured a. Nodules i. Cannonball ii. Small iii. Hazy Unstructured Interstitial

21 More mild interstitial The classic Bronchointerstitial cases Structured Interstitial - cannon ball mets

22 Smaller less distinct mets Bronchial Pattern Doughnuts (or bagels if you prefer) Tram/Train lines Textbook example Bronchiectasis

23 Feline asthma Bronchial Bronchial Bronchial

24 QUESTIONS!Thanks for listening! And then there will be these kind of cases Crazy Cases

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