Diagnostic radiology - Radiography Flashcards
How X-rays are produced?
tungsten filament is heated, electrons are ejected from the surface of the filament
Voltage (a large electrical potential) between the cathode and the anode forces electrons emitted from the filament to accelerate towards the anode, hit on tungsten target (e.g. titanium)
energy conversion when a fast-moving stream of electrons suddenly decelerates produces x-ray
Special films for Pneumothorax, pleural effusion and wrist fracture?
Pneumothorax = inspiratory and expiratory film
Pleural effusion = decubitus film
Wrist fracture = scaphoid view
Difference between conventional and digital radiography?
Advantage?
Digital = phosphor imaging plate connected to computer
- Complex image processing
- Electronic storage (easier to compare)
- Electronic image transmission
Indications for mammography?
- Screening: asymptomatic, early detection of small breast cancers (e.g. DCIS)
- Diagnostic mammography: Symptomatic, detect mass
3 views on mammography?
Medial lateral oblique view
Craniocaudal view
Special view: Compression paddle to spread out breast tissue, magnify to show small microcalcifications and lesions
Mammography finding: Indications of lesion with
- Well-defined border, round?
- Speculated, irregular border?
- Large, clustered dots?
- Small specks that follow ducts?
Well defined border, round – cyst
Denser with speculated border and clumps of small
microcalcifications – breast cancer
Benign calcification = big, clustered
Malignant calcification (e.g. small dots that follow ducts) – ductal carcinoma in situ
Effect of age on mammography sensitivity?
Sensitivity decreases in dense breast:
Old: glands replaced by fat = easier to spot pathology
Young: glandular = whiter
mammogram are less sensitive in young patients (US more appropriate)
Name of X-ray exam to Demonstrate the urinary tract for suspected urinary tract pathology
Intravenous urogram (IVU)
Indications for Intravenous urogram (IVU)
Mechanism?
hematuria, loin pain
Uses intravenous nonionic contrast which are excreted in kidney to ‘contrast’ urinary system – looks white on X-ray
Patient preparation for intravenous urogram
Laxative (decrease fecal matter, can be mistaken as mass)
Fast for 4 hours
Hydration (increase distension of urinary collecting system)
Vascular accesses
Assessment before injection of IV contrast for intravenous urogram?
Patient preparation during exam?
Look for calcifications (e.g. ureteric stone) before injecting contrast
Compression band: presses down the top of bladder to adequately distend the pelvicalyceal system for evaluation
How to assess for urinary retention on IVU?
Do 2 films:
Full bladder and post-micturition films
Fluoroscopy
- Difference from X-ray
- Contrast medium used?
- Continuous exposure of X-ray gives dynamic view of moving body structures
- Barium, water-soluble contrast medium, Air
Barium exam complications?
Perforation:
Barium peritonitis from peritoneal adhesions, granulomata
Aspiration into lung:
Barium pneumonia, need Physiotherapy
Barium exam patient preparation
Fasting
Bowel prep: low residual diet for 3 days, laxatives
IV Buscopan: bowel relaxant, reduce bowel preistalsis, Increase distension for better assessment
Procedure for barium enema
Barium release into rectum + air inflation for double contrast
Patient rolled around for different views
Barium enema show:
- Outpouching of colon
- Apple core appearance of colon
Suggestive of what diseases?
Outpouching = diverticula
Apple core appearance = colorectal cancer
5 symptoms and signs to indicate barium enema?
Change in bowel habit Pain Mass Blood in stools Bowel obstruction
Absolute precaution with barium studies
Must use water-soluble contrast instead of barium contrast for suspected intestinal obstruction
to avoid barium peritonitis after perforation
2 types of small bowel barium studies?
Small bowel follow through: oral intake of barium
Small bowel enema: Catheter inserted through nostril (naso-gastric tube) through to duodenal-jejunum junction to inject barium and methylcellulose
Small bowel follow through and small bowel enema.
Advantages
Disadvantages
Small bowel follow though
+ Easier oral intake of barium solution, less discomfort
- Delayed film for small bowel evaluation, single contrast, less wall detail
Small bowel enema
+ Better distension and double contrast, better detail
- Discomfort
5 symptoms to indicate Barium meal?
What other visualization procedure has replaced most barium meal exams?
stomach, duodenum
Dyspepsia, epigastric pain
Weight loss
Assessment for suspected stomach cancer
Suspected perforation of peptic ulcer
Upper GI endoscopy
Procedure of barium meal?
- Oral intake of barium solution
- Effervescent granules produce gas for double contrast - better mucosal detail
- Roll patient to different angles for views
2 methods to visualize biliary tree?
- Percutaneous cholangiogram
2. T-tube cholangiogram (skin to CBD)
Percutaneous cholangiogram
- Indication
- Contraindication
Indications:
- Biliary obstruction: stone, tumor, extrinsic compression
- Bile leak
Contraindication: biliary sepsis
Indications for Angiogram
Assessment of arterial/venous disease, e.g. renal artery stenosis
Localization of site of hemorrhage +/- embolization
Fluoroscopic examination of vessels
(intravascular injection of contrast)
Patient preparation for angiogram
Fasting
IV access
Clotting profile, platelet
Method to show vessels against a clearer background in angiogram?
digital subtraction angiogram
subtracts background structures e.g. bones
Adverse reactions to intravascular water-soluble contrast medium for angiogram?
Mild: sneezing, nausea
Moderate: pruritis, flush, fever / chills, increased /
decreased blood pressure
Severe: difficulty in breathing, periorbital edema,
cardiac arrhythmia, pulmonary edema, death
5 ways to reduce radiation exposure
Avoid unnecessary examination
Use alternative: USG, MRI (particularly in pediatric, pregnant patients)
Shielding of organs, e.g. gonad shield, lead apron, thyroid shield, glasses
Filtration of X-ray beam
Control of irradiation and recording of irradiation time
