Imaging Exam 3: 3.1-3.3

routine radiograph views for chest

PA, lateral

patient positioning for chest imaging

Weight bearing

observations from PA chest view

some of diaphragm, left ventricle, descending aorta

patient positioning for lateral chest view

Weight bearing, arms up to avoid superimposition

observations from lateral chest view

trachea, heart, left & right hemidiaphragm

which side of the diaphragm appears higher in imaging?

right

A-F visualization for chest imaging

A: trachea, B: bones, C: circulation, D: diaphragm, E: edges, F: fields

how much of the chest space should the heart take up in an AP view?

half

what is the silhouette sign in chest radiographs?

cannot see heart outline clearly

how does a tension pneumothorax appear in a radiograph

deviated trachea, heart may be shifted to one side, unequal lung spaces

what is the initial imaging option for any cause of hip pain?

radiograph

when would you use a CT for hip pathology?

complex or hidden fractures

what is the most common hidden fracture in the hip?

posterior acetabulum

routine radiographs for pelvis

AP

routine radiograph views for hip & proximal femur

AP pelvis, unilateral AP hip, unilateral frog leg

patient positioning for AP pelvis view

supine with hips in 15° IR

4 major lines to trace in AP pelvis view

iliofemoral, iliopubic, ilioischial, Shenton’s

4 major landmarks to trace/visualize in AP hip&femur view

anterior rim, posterior rim, and roof of acetabulum + radiographic teardrop

what is the normal range for center edge angle and what do smaller & larger angles mean?

23-25°. smaller angle = more unstable, larger angle = bony limit to ROM

femoral neck-shaft angles

coxa vara <100°, coxa valga >135°

patient positioning for lateral frog leg view

supine figure 4 position

structure best visualized from lateral frog leg view

lesser trochanter

observations from cross table lateral view of hip

better exposed femoral head/neck, lesser trochanter, ischial tuberosity

normal alpha angle in Dunne Lateral view

<57°

trauma views for hip & pelvis

Judet, AP axial inlet & outlet

patient positioning for Judet view & observations

turned 45° from table, better view of acetabulum for fractures/dislocation

observations from AP axial inlet view

SI joints for posterior displacement, sacrum, pelvic ring, pubic diastasis

observations from AP axial outlet view

rami & SI joints

observations from CT coronal view of hip

bilateral comparison of hip joints, acetabulum, proximal femur, sacrum, SIJ

observations from axial oblique MRI

basically everything

lateral hip pain frequently suggests pathology ____ of the joint

outside

2 most common causes of trauma fractures in the hip & pelvis

osteoporosis, AVN

what does FAI stand for?

femoral acetabular impingement

4 common hip & pelvis pathologies in pediatrics

avulsion fractures, Legg-Calve-Perthes Disease, Slipped capital femoral epiphysis (SCFE), septic arthritis

what is a SCFE?

femoral head falls off neck. usually in adolescent boys

how are stable vs unstable pelvic fractures determined?

stable if pelvic ring is intact, unstable if disrupted

what region makes up 50% of pelvic fractures?

ischiopubic ramus

MOI for avulsion fractures & most common sites

sudden forceful muscular contraction. ischial tub, ASIS, AIIS

from what sports action do we typically see AIIS avulsion fractures?

kicking

how does AVN in the hip appear radiographically?

maybe nothing or radiolucent crescent

observations from CT sagittal view

anterior inclination of acetabulum, acetabulum roof, iliopsoas, SIJ, pubic symphysis

routine views for knee

AP, lateral

extra views for knee

tunnel view, tangential patellofemoral view, oblique view

what structure is the ‘lighthouse’ of the knee?

fibula

which structures are superimposed in the knee AP view?

patella, fibula

patient position for knee lateral view

sidelying with knee flexed 20 degrees

what is the fabella and in what view is it seen?

sesamoid bone embedded in head of gastroc, seen in lateral view

what does the Insall-Salvati ratio measure?

patellar tendon length: patella length

what does patella alta mean?

patellar tendon length > patellar length

what does patella baja mean?

patellar length > patellar tendon length

patient position for knee tunnel view

prone with knee flexed 40 degrees

what are we trying to view in the knee tunnel view?

intercondylar fossa if suspicion of tibia plateau fx or ACL avulsion fx

patient position for tangential patellofemoral view

seated or supine with knee flexed 45 degrees

how to tell medial vs. lateral in tangential knee view

lateral femoral condyle is taller, lateral facet of patella is bigger

what does a flatter sulcus angle suggest?

more likely to subluxate or dislocate

how to measure congruency angle

from base of sulcus to apex of patella

internal oblique view of the knee

rotated 45 degrees to observe LFC & fibular head without superimposition

external oblique view of the knee

rotated 45 degrees to observe MFC without superimposition

Ottawa Knee Rules (acute injury)

1. Age >55

2. isolated tenderness of patella

3. fibular head tenderness

4. cannot flex knee to 90 degrees

5. cannot bear weight both immediately and in ED for 4 steps

Pittsburgh Knee Rules

for blunt trauma or a fall as MOI + age <12 or >50, cannot walk 4 steps in ED

names of overuse injuries in the knee

Sinding Larsen Johansson (patella), Osgood Schlatter’s (tibia)

first line of imaging for patella subluxation & dislocation

radiographs

what is the primary medial ligamentous restraint of the knee?

medial patellofemoral ligament

normal meniscus appearance

dark black, bowtie appearance

bucket handle meniscus tear appearance

meniscus folds over

meniscus root tear appearance

slides out laterally from joint

ankle routine views

AP, lateral, oblique (mortise)

patient position for ankle mortise view

internal rotation of foot and ankle 15 degrees

why do we need the ankle mortise view?

to observe mortise joint space and distal tib-fib joint

what is Boehler’s angle used for

detect and assess calcaneal fractures

what points are used to find Boehler’s angle?

posterior tuberosity, posterior facet, anterior process

what are the inversion/eversion ankle stress views used for?

evaluate stability, assess for abnormal widening of mortise joint

limitations of ankle stress views

difficult to differentiate severity of ligamentous involvement

routine views of the foot

AP, lateral, oblique

patient position for AP foot

plantarflexed on top of image receptor

what foot joints make up Chopart’s joint?

talonavicular, calcaneocuboid

what foot joint makes up Lisfranc’s joint?

tarsometatarsal

how is a bunion determined?

>16 degree angle between digits I and II

which metatarsal is most commonly fractured and why?

2nd, longest & thinnest

patient position for foot oblique view

lateral border elevated 45 degrees

why do we get oblique foot views?

better view of metatarsals and phalanges

Ottawa ankle rules = pain either malleolus AND

tenderness at posterior aspect or tip of either malleolus, or inability to bear weight

Ottawa foot rules = pain in midfoot AND

tenderness at base of 5th met or navicular, or inability to bear weight

first imaging technique for ankle & foot trauma

radiographs

high % of ___ suggest infection

neutrophils

what is C-Reactive Protein useful for?

monitoring effectiveness of treatment

importance of ESR

most sensitive for infection

importance of HLA-B27

indicative of autoimmune disorders, ankylosing spondylitis

spinal infection imaging & lab values

MRI most sensitive imaging (appears foggy), ESR most sensitive test