Radiology Flashcards
Discuss the components of the centrifugal approach of reading a head CT, as compared to centripetal which is used for head trauma.
Midline: examine for any midline shift and the midline structures
Ventricles: examine the lateral, 3rd, cerebral aqueduct, and 4th ventricles as well as the cisterns
Brain parenchyma: examine the lobes of the brain as well as other structures (deep nuclei, brainstem, tentorum cerebrelli, sulci)
Bony calvarium: examine the bones and sinuses
Soft tissue: examine the soft tissues outside of the skull
Discuss some hypo-dense and hyper-dense structures on CT
Hypo-dense (dark): Edema Ischemia Fat Air Hyper-dense (light): Blood Calcification
Name the sinuses
Ethmoid Sphenoid Superior saggital Frontal Maxillary
List the different types of brain hemorrhages, the most likely vessel and characteristic radiographic sings
Epidural: caused by the middle meningeal artery
- biconvex, lens shaped hyperdensity that stops at the suture lines
Subdural: caused by cerebral veins
- concance hypersensity
Sub-arachnoid: rupture of cerebral arterial aneurysm
- hyperdensity in fissures and cisterns
Intra-cerebral: caused by lacunar arteries
- hyperdensity at deep nuclei
List the findings for the following:
Acute (<3 days) intra-cranial hemorrhage:
Sub-acute (3-14 days) intracranial hemorrhage:
Chronic (>14 days) intracranial hemorrhage:
Acute (<3 days) intra-cranial hemorrhage: hyperdensity
Sub-acute (3-14 days) intracranial hemorrhage: isodensity
Chronic (>14 days) intracranial hemorrhage: hypodensity
How long after symptoms of an ischemic stroke begin can tPA be considered?
3-4.5 hours after onset of symptoms
List findings of an ischemic stroke on CT imaging
May be normal - must r/o hemorrhagic stroke
- Hyperdense vessel from thrombus or embolus
- Insular ribbon sign: blurring of grey and white matter from outside to inside at the insular cortex, insular capsule and lentiform nucleus
- loss of grey/white matter junction
- effacement of sulci due to edema
Late Findings:
- have hypodensity due to edema with possible mass effect
List the MRI findings of meningitis
Enhancement of CSF on FLAIR sequence
List the findings for a brain abscess with CT imaging
Without contrast: area of hypodensity
With contrast: ring enhancement surrounded by area of hypodensity
Lis the CT findings for cysticerosis
Without contrast: Cyst with central nodule surrounded by calcification ring
Compare the CT features of a benign and malignant brain tumour
Benign: - extra-axial making contact with meninges - Smooth borders Malignant: - intra-axial - irregular borders - central low density area due to necrosis - hypodensity surrounding - mass effect - post-contrast enhancement
List the radiographic findings of a lung pneumonia
- Consolidation
- Increased opacity surrounding the pulmonary vessels
- air bronchogram (visible travelling bronchi)
- silhouette sign
List the location of consolidation if the silhouette sign is present
Right heart border occluded: RML
Right hemidiaphragm occluded: RLL
Left heart border occluded: lingual
Left hemidiaphragm occluded: LLL
List the three types of pneumonia that can be discerned based of chest x-ray
Bronchopneumonia: patchy consolidation with multiple foci in both lungs
Lobar pneumonia: consolidation that is localized and continuous region of lung
Interstitial pneumonia: increased dots and lines (reticular nodular pattern)
List the radiographic features of pulmonary edema
Go from vascular redistribution -> interstitial pulmonary edema -> alveolar pulmonary edema
Vascular redistribution:
- vessels in upper lobes are similar or larger than lower lobe vessels
Interstitial pulmonary edema:
- peribronchial cuffing (see black hole)
- vascular indistinctiveness of hila and pulmonary vessels
- Kelley B lines
- pleural effusion
Alveolar pulmonary edema:
- bilateral consolidation (butterfly pattern)
Differentiate between a benign and malignant lung nodule
Benign - <1cm - no growth - discrete - smooth or lobulated - increased density - central or diffuse calcifications Malignant - >=1cm - Rapid growth - spiculated - irregular - decreased density - ground glass appearance
Differentiate between a lung nodule and a lung mass
Nodule: <3cm
Mass: >=3cm (more likely to be malignant)
List the radiographic features of the following lung cancers: Squamous cell carcinoma Adenocarcinoma Bronchio-alveolar adenocarcinoma Small cell lung cancer Larger cell lung cancer
Squamous cell carcinoma: - centrally located - intrathoracic - cause atelectasis - spread within lung Adenocarcinoma: - solitary and peripherally located - spread to hila and mediastinal nodes Bronchio-alveolar adenocarcinoma: - consolidation with air bronchogram or ground glass appearance - multiple foci Small cell lung cancer: - centrally located - hilar/mediastinal node involvement - early distant metastases Larger cell lung cancer: - peripheral or central
How do you differentiate between a primary lung tumour and a metastasis?
Primary tumour usually have larger tumour along with the multiple foci Metastasis have multiple tumours with no obvious primary tumour. Common locations: - breast - colon - melanoma - head and neck - renal cell carcinoma - sarcoma
What are the radiographic features of a pneumothorax?
- Increased blackness on periphery
- sharp demarcation of the collapsed lung
- deep sulcus sign: visualization of posterior diaphragm on supine x-ray
- Tracheal deviation (away from collapsed side)
- subcutaneous emphysema
Discuss the findings of pneumoperitoneum
Standing x-ray:
- air under the diaphragm
Supine x-ray:
- Riglers sign: black air resulting in both sides of the bowel being visible
- Football sign: football shaped lucency in the central abdomen
- Cupola sign: free air in mid-subphrenic space
List the x-ray findings of a small bowel obstruction
- Distention of bowel loops
- air/fluid levels on standing x-ray
- Small bowel loops:
- dilated bowel loops are located centrally
- smaller diameter
- pliae circularis that go around the small intestine
- thicker wall with white border
List the x-ray findings of a large bowel obstruction
- dilated large (possible small) with air/fluid levels
- dilation of large bowels:
- located peripherally
- larger diameter
- haustra that do extend the entire length of the bowel diameter
- thin walls with no white outline
List the differential for calcifications seen on abdominal x-ray
Calculi: renal, uteric, gallbladder
Vasculature: phlebolith, severe atherosclerosis of artery
Organ: pancreas, appendicolith
