Flashcards in Radiology 1, 2 3 Deck (76)
How are x-rays formed?
The cathode directs a stream of electrons into a vacuum, which collects the electrons. When the electrons hit the anode, about 99% of the resulting energy is emitted as heat with the other 1% being emitted as x-rays.
How many mSv does an x-ray emit?How many mSv does a chest CT emit?
What causes blunting of the costophrenic angle?
Usually a pleural effusion but it can also be caused by lung disease in the region of the costophrenic angle or hyper expansion
What is situs inversus?
an uncommon condition in which the heart and other organs of the body are transposed through the sagittal plane to lie on the opposite (left or right) side from the usual.
What is the cardiothoracic ratio (CTR)?what is an abnormal ratio?
Cardiac width: thoracic widthA CTR of greater than 1;2 is abnormal (50%)
What can exaggerate the size of the heart?
if the patient doesn't breath fully
What kind of congenital malformation can be seen on the bronchial tree on imaging?
Hilar bronchogenic cysts
What lobes of the lung can be mainly seen on frontal radiography?
What lung lobes are seen in posterior radiography?
What type of fissure does both lungs have?
ObliqueRight lung also has a horizontal fissure
What allows the different types of tissue present on a CT scan to be compared?Unit?
Each tissue has distinct densitiesHounsefield unit
What happens to a silhouette on imaging when you have 2 tissues of the same density together?
You lose the sillhouette
What are 2 other names for a mycetoma?What is this?
AspergillomaFungus ballA clump of old which exists in a body cavity caused by fungi of the genus apergillus
What causes the appearance of lots of different dots in the lungs?
Miliary Tuberculosis (TB) - widespread dissemination of Mycobacterium tuberculosis via hematogenous spread
What lung disease is huge hillier lymph nodes a sign of?
What is consolidation?
radiological sign that refers to non-specific air-space opacification on a chest radiograph or chest CT
What 2 questions regarding a PTE should be asked before a D-dimer is measured?
Is another diagnosis unlikely?Is there a major risk factor?Measure D-dimer if only 1 of the above answers is raised
What are the major risk factors for a PTE according to radiology form? (6)
Recent immobilityPregnancy/ post partumMajor medical illnessMajor surgeryPrevious VTELower limb trauma or surgery
what 3 questions should be considered when thinking about referring for a CTPA or V/Q scan (PTE)?Results needed to get a scan
Is another diagnosis unlikely?Is there a major risk factor?Is the D-dimer raised? (only measure if only 1 of the above answers is YES)CTPA or V/Q scan will only be done if 2 or more are YESIf
What does CTPA stand for?
CT pulmonary angiography
What is a V/Q scan?
Involves 2 types of radioisotope scans - patient inhales radioisotope gas and has radioisotopes infected into their veins - scan compares ventilation and blood flow in the lungs
What imaging is indicated for a PTE when CXR is normal?
What imaging is indicated for PTE when radiation has tO be avoided/ left swollen?
Consider US leg for DVT
What imaging is indicated for PTE if CXR abnormal/ massive PE suspected?
What is the usual isotope used for V/Q scan?
If the patient has a PTE, what will a V/Q scan show?
Normal ventilation with abnormal perfusion
What are the 4 factors you have to look at to assess if a lung x-ray is technically adequate?
How to check penetration?
You should be able to see the thoracic spine through the heart
How to check inspiration?
About 10 posterior ribs visible in an excellent inspiration, although in many hospitals 9 is adequate