4- radiology of thorax 2 Flashcards
what are major risk factors for pulmonary thromboelmbolism?
- immobility
- major surgery
- pregnancy
- lower limb trauma or surgery
- previous VTE
- major medical illness
what score can be used to assess severity of pulmonary thromboembolism?
Pulmonary embolism severity index (PESI)
what investigations should be done if chest x-ray normal?
V/Q scan
what is investigations for pulmonary thromboembolism if radiation needs to be avoided e.g. in pregnancy?
consider ultrasound of leg
if chest x-ray abnormal or massive PE suspected what investigation should you do?
CT pulmonary angiogram
what is chest x-ray like in pulmonary embolism?
often looks normal = good for excluding other diseases but not good for identifying pulmonary embolism itself
what would you expect to see on normal perfusion scan?
would expect normal lungs to have uniform perfusion - would inject something into veins and it should in normal person distribute evenly
what is perfusion scan?
ventilation perfusion scan (V/Q scan)
= small amount of tracer substance injected into vein in arm, this then carried through bloodstream and gets trapped in capillaries allowing visualisation of blood flow distribution
what does uneven distribution in V/Q scan suggest?
may suggest underlying problems like pulmonary embolism (as lung distal to clot not perfused), pulmonary hypertension
what is good way to remember how to tell which side which in CT scan?
imagine standing at patients front looking up at them
what can be done to treat DVT?
- DVT thrombolysis can be done to break up clot and prevent recurrence of DVT
- can also do mechanical disruption like catheter directed thrombectomy
what are pulmonary nodules?
masses that you can see in lungs
-can be benign (well defined) or malignant (malignant less defined)
what is a hamartoma and what are hallmarks?
hamartoma = benign lesion
hallmarks = defined, popcorn lesion (popcorn appearance due to calcification which can be seen on x-ray but better seen on CT)
what are predisposing conditions of lung cancer?
- inhalation of carcinogens e.g. cigarette smoke, asbestos
- bronchioalveolar adenoma
- interstitial pulmonary fibrosis
- previous lung cancer. remember tumour can be synchronous (more than 1 tumour at same time) and metachronous (another tumour at different time)
what are peripheral tumours?
lung tumours distal to hilum
what are central tumours?
tumours at hilum or more proximally = much harder to see (usually see hilar enlargement or distal collapse/consolidation)
what are some signs of central mass on xray?
- elevated diaphragm
- blunting of costophrenic angle
what is TNM staging of lung cancer?
Tumour = what is size + distribution in primary organ?
Nodes = are there associated lymph nodes involved?
Metastases = are there any deposits anywhere else?
what scans can be used for staging of tumour?
- CT (good for assessing size and guided biopsy)
- PET (good for detecting distal metastases)
- MR (good as don’t need Iv contrast which some people are allergic to but time consuming)
what are radiological interventions for lung cancer?
- CT guided biopsy
- pleural fluid drain
- SVC stenting
what is the upper, mid and lower zone of lungs on chest x-ray?
1st 2 ribs = upper zone
ribs 2-4 = mid zone
below 4 = lower zone
what are signs of pleural effusion on x-ray?
- look at difference of costophrenic angle. accumulation in pleural space may blunt angle
- look at meniscus sign = curved line or meniscus shape along lateral aspect, represents interface between pleural fluid and surrounding air in pleural space
what is purpose of SVC stenting?
stent to open up vessels
how quickly does asbestos lead to mesothelioma?
a long time - years
