Intro to General Principles of MSK Imaging Part 2 Flashcards
How to view a radiograph
- view a plain film as if you are facing the patient
- a minimum of 2 markers is usually imprinted on every radiograph
Identification markers
- provides pt identification
- establishes anatomic side (R or L)
- weight bearing or (ERECT) indicates pt was standing for exam
- decubitus (DECUB) indicates that the pt was recumbent
- inspiration (INSP) & expiration (EXP) are used in comparison films of the chest indicating the state of respiration
Describe the saying “one view is no view”
- the minimal radiographic examination includes 2 views of the imaged body part at right angle to each other
Define angles of projection
- the path of the x-ray beam as it travels from the X-ray tube through the pt to the image receptor
How many dimensions does a single X-ray provide
- a single X-ray provides only 2 dimensions (LxW)
How do you determine depth with an x-ray
- to determine depth a 2nd x-ray is required at a right angle (90º) to the 1st
What are the most common views for X-rays
- AP (anterior to posterior)
- lateral: x-ray beam has traveled through the body at right angles to the AP or PA projection/view
- oblique: involves rotation of a body part so that the beam travels through the body part at an angle between the AP & lateral views
Radiographic positions that best visualize intervertebral foramina versus zygapophyseal
- Intervetebral: oblique 45º (cervical spine), lateral (thoracic spine), lateral (lumbar spine)
- Zygapophyseal: lateral (cervical spine), oblique 70º (thoracic spine), oblique 45º (lumbar spine)
What is the only body part that is evaluated with a PA view instead of an AP view
- hand
Define position
- the pat’s physical position
- general body position (supine, seated, standing)
- wbing versus non-wbing
- the body part closest to the image receptor offers the best detail
Primary radiographic body positions
- upright
- seated
- recumbent
- supine
- prone
- trandelenburg
Factors related to image quality
- Photographic: density = blackness, contrast = variation amongst densities
- Geometric: detail = sharpness/motion, distortion = object is not perpendicular to X-ray beam
What is included in the routine radiographic exam
- offers the most visualization of structures with the least number of radiographs
- lowest amount of radiation to create a quality image study
- ACR appropriateness criteria
Possible radiographic results from routine exam
- Positive for hypothetical clinical diagnosis
- Negative for hypothetical clinical diagnosis
- Negative for hypothetical clinical diagnosis but raises suspicion for an alternate diagnosis
- Inconclusive: additional imaging needed
- Wrong: False Neg./False Pos.
What view is a chest radiograph always taken at
- PA view
What are the different views for cervical spine plane films
- AP view
- Lateral view
- Open mouth view (odontoid/dens view)
- Anterior Oblique view (right or left)
- Swimmers view (addresses the issue with poor visualization of C7; AKA modified lateral projection of cervical spine)
What are the different views for shoulder & humerus plain films
- AP view with IR and ER
- Axillary view
- Y view (shot at an angle that separates the scapula and humerus from the chest)
- shoulder trauma protocols suggest at least 3 views
What are the different views for elbow plain film
- AP view
- Lateral view (elbow flexed at 90º)
- Signs of pathology: fat pad (think fx if see), sail sign (think fx if see), growth plates (well defined boarders)
What are the different views for hand and wrist plain films
- PA view
- Lateral
- Oblique (lose overlap of carpal bones)
- Scaphoid view: scaphoid fx suspicion
- Carpal tunnel view: hamate fx suspicion
Current American College of Physicians lumbar plain film series recommendations
- Imaging is only indicated for severe progressive neurological deficits or when medical flags are suspected
- Routine imaging does not result in clinical benefit & may lead to harm
What is the low back pain (LBP) CPG (clinical practice guideline) for radiographs
- Mobility deficits: no imaging with back pain lasting ≤1 mo, no red flags
- Referred LE pain: adults >65 yrs in whom imaging changes are ubiquitous, severity of disc/facet disease was not associated with pain severity
- Related generalized pain: non-indicated imaging should be strongly discouraged
What are the different views for pelvis plain film
- Usually only need AP view: male pelvic is triangular and female pelvic is rounded
- Pelvis is a ring: fx in more than one place
- Suspected slipped capital femoral epiphysis (SCFE): Frog view (Peds)
What are the different views for knee plain films
- AP view
- Lateral view
- Sunrise/Merchant view (patella focused)
- Tunnel view: PA with bent knee looking between the femur and tibia
What are the different views for foot and ankle plain films
- Ankle: AP view, Lateral view, Mortise view (best for identifying a fx)
- Foot: AP view, Lateral view, Oblique view (best for seeing metatarsals)
Describe alignment for radiographic interpretation
- General skeletal architecture: size, shape, number, and alignment
- Pathology appreciated: fracture, dislocation, and cortical alterations
Describe bone density for radiographic interpretation
- General & focal bone density: check contrasts & osteoporosis (X-ray not gold standard)
- Textual abnormalities: abnormal trabecular architecture indicates metabolic bone disease
- Local bone density changes: sclerosis at areas of increased stress, fracture healing
- Pathology visualized: metabolic bone disease, infection, tumor, arthritic changes
Describe cartilage spaces for radiographic interpretation
- Joint space width and symmetry: well preserved joint spaces imply normal cartilage or disk thickness
- Contour and density of subchondral bone: smooth surface
- Epiphyseal plates: normal size relative to epiphyseal & skeletal age
- Pathology: degenerative and rheumatoid arthritis
Describe soft tissues for radiographic interpretation
- look at soft tissues for gross swelling, capsular dissension, periostea elevation
- Muscles: soft tissues normally exhibit a water-density shade of gray
- Fat pads/fat lines: normally radiolucent and parallel to bone/muscle
- Joint capsules: normally indistinct
- Periosteum: normally indistinct
Describe intra-articular fracture and inter-articular fractures
- Intra-articular fracture: fracture line crosses into the joint
- Inter-articular fracture: fracture line crosses outside of the joint
ABCs: search pattern for radiographic image interpretation
- Alignment
- Bone density
- Cartilage spaces
- Soft tissues
Carpals bones in their rows
When are they likely to ask for a weight bearing film images
- when looking at cartilage space especially for hip/knee OA diagnoses
Define heterotrophic ossification (HO)
- diverse pathologic process
- the formation of extra skeletal bone in muscle & soft tissues
- can be conceptualized as a tissue repair process gone awry and is a common complication of trauma and surgery
Describe errors in observation and interpretation
- Observation: incomplete of faulty search pattern
- Interpretation: failure to link abnormal radiographic signs to relevant clinical data
What is included in the radiologic report
- Heading
- Clinical information
- Findings
- Conclusions/Impressions
- Recommendations (optimal)
- Signature of radiologist
What does the heading include
- Facility information: identification & address of facility, date of examination
- Patient information: name, age or date of birth, gender, case number
- Radiographic information: what anatomy part was examined, the number of views obtained
What does the clinical information include
- includes a brief summary of relevant data in the history, physical examination, & laboratory studies
- Location, duration, onset, & symptoms
- History of injury
- Positive orthopedic or neurological tests
- Prior imaging
- Abnormal laboratory studies
- Abnormal physical examination findings
What does the findings include
- Body of the report
- Presented in a narrative form with complete sentences, professional terminology, & absence of eponyms or jargon
- Describes the radiographic abnormalities or normal appearance; does not state diagnosis except for fx or dislocation
What does the conclusions include
- Could be labeled: impression, diagnosis, judgement, interpretation, or reading
- Is a point by point summation of the data presented in findings
- Conditions are labeled & diagnoses are reported
- Diagnoses are reported in order of severity, beginning with the most serious condition
What does the recommendations include
- Optimal section that appears only if follow up procedures are indicated
- Recommendations are specific for the condition diagnosed or suspected
- Recommendations may include additional conventional radiographs, optimal projections or positions, other imaging modalities, laboratory evaluation, or referrals to other healthcare providers
What does every radiograph report must have
- All reports must be signed
Malignant versus benign bone tumor
- Malignant: wider than it is long, irregular borders, invades the joint space, grows outwards from the bone
- Benign: longer than it is wide, grows along the bone, well defined borders, does not invade the joint space