Imaging Exam 3

Routine views of the chest

PA chest and lateral chest

What we see on PA chest view

diaphragm, left ventricle, descending aorta

What we see on Lateral chest view

trachea, heart, diaphragm

Pathologies we can see on PA chest view

enlarged heart, depressed diaphragm, pneumonia (silhouette sign = radiopaque spot on chest wall), pneumothorax (heart shifted)

Imaging options for Hip

rads first, MRI next, CT for complex fracture

Routine views of pelvis

AP pelvis

Routine views of Hip/Prox femur

AP pelvis, unilateral AP hip, unilateral lateral hip/frog leg

AP pelvis view

Pt supine with 15 degrees IR, can see many structures and lines

Unilateral AP hip/prox femur view

Pt supine with 15 degrees IR, good view of ASIS, AIIS, acetabulum (wall/roof)

lateral frog leg view of hip and prox femur

Pt supine figure 4 position, great to view lesser trochanter, intertrochanteric line, femoral neck

Axiolateral Inferosuperior (cross table) projection of hip and prox femur

Supine with leg flexed in air, ray shot underneath the leg thats lifted, good for femoral head/neck, ischial tuberosity, lesser trochanter

Dunne lateral view

good for alignment of femoral head, occult fractures

Judet view

oblique pelvis view (45 degrees), good for posterior acetabulum (no superimposed femur), iliac wing

AP axial Inlet view (femoral heads must be included in view)

Pt supine with ray shot top-down, good for SI joint displacement/sacrum, opening of pelvis/pelvic ring, spinous process of lumbar, pubic diastasis

AP axial Outlet view

Pt supine with ray shot bottom-up, good for ramus, SI joint, pubic symphysis

CT axial view of hip/pelvis

good to isolate posterior acetabulum without superimposition

CT coronal view of hip/pelvis

good for comparison between hips, femur, trochanters, medial acetabulum walls

CT sagittal view of hip/pelvis

good for acetabular roof, iliopsoas, sacroiliac joints, pubic symphysis

imaging modality for osteoporosis vs avascular necrosis

osteoporosis = DXA, avascular necrosis = MRI

pain from groin can localize pain to which area

the knee

Stable vs unstable pelvic fractures

stable fractures the pelvic ring is intact (ramus fractures), unstable it is not (pubic diastasis)

5 types of stable pelvic fractures

avulsion, iliac wing, sacral, ischiopubic ramus fractures (ipsilateral & contralateral)

Avulsion fractures of hip/pelvis

most common in young athletes, sudden forceful contraction, common sites 1 = ischial tube, 2 = ASIS, 3 = AIIS

Avascular necrosis of hip on radiograph

maybe nothing, sometimes radiolucent crescent sign on femoral head

Septic arthritis of hip on radiograph

joint erosion, rapid destruction of bone

Routine views of knee

AP and lateral

AP view of knee

Pt supine, superimposed patella, good for joint space, alignment

Lateral view of knee

Pt sidelying with knee flexed 20 degrees, good for fabella, patellar alignment

Pattellar tendon length : Patella length (insall-salvati ratio)

patellar tendon should be around 1 to 1 ratio with patella

tunnel view

Pt prone with knee flexed 40 degrees, can see through intercondylar fossa

tangential patellofemoral view

Pt seated with knee flexed 45 degrees, good for sulcus angle, congruency angle, peels patella off femur

sulcus angle

angle of femur condyles that form divot for patella

congruency angle

angle showing how the patella sits in the sulcus (vertical line from sulcus and posterior patella)

how to tell medial and lateral on tangential patellofemoral view

medial patella is more flat, lateral femoral condyle sticks out farther

internal oblique of knee

Pt internally rotated 45 degrees, shows lateral knee, lat femoral condyle, fibular head

External oblique of knee

Pt externally rotated 45 degrees, shows medial knee, medial femoral condyle, fibula is superimposed

Ottawa knee criteria (AFTER ACUTE TRAUMA)

age >55, tenderness of patella/fibula, inability to flex past 90, cannot weight bear 4 steps (limping ok)

Pittsburgh knee criteria (AFTER ACUTE TRAUMA)

age <12 or >50, cannot weight bear 4 steps (limping ok)

Sinding Larsen Johansson syndrome (scarlet johansson syndrome)

osgood schlatters of patella

Imaging options for patella dislocation

rads first, MRI next to see ligament damage (medial patellofemoral ligament)

how to know if a ligament/fibrocartilage is damaged on an MRI

high signal intensity

Ankle routine views

AP, lateral, oblique (mortise)

AP ankle

Pt supine w leg in neutral, good to see malleoli, fibula superimposed

oblique (mortise) ankle view

Pt internal rotated 15 degrees, good for distal tib-fib joint, joint space (mortise)

lateral ankle view

Pt sidelying, can see sinus tarsi (talocalcaneal space), boehlers angle, calcaneal pitch

boehlers angle

alignment of talus on calcaneus, if abnormal then occult fracture

ankle inversion/eversion view

looks for gaps in ankle joint space

ankle anterior drawer view

pulls tibia posterior and calcaneus anterior, see ligament weakness, can be done on ultrasound

foot routine views

AP, lateral, oblique

AP foot view

Pt planterflexed to see digits, good view of chopart joint and lisfranc joint, bunions

Chopart joint vs lisfranc joint

chopart = talonavicular/calcaneocuboid, lisfranc = tarsometatarsal

Lateral view of foot

Pt sidelying, can see chopart, lisfranc, and talocrural joint, sinus tarsi

Oblique view of foot

Pt hooklying, can see base of metatarsals, 3rd cuneiform with no superimposition

Ottawa ankle criteria

tenderness @ posterior medial/lateral malleolus OR inability to bear weight

Ottawa foot criteria

tenderness @ 5th met/navicular OR inability to bear weight

WBC norms

5-10

C reactive protein (what it shows and norms)

shows systemic infection, norms = 0-1 mg/dl

Erythrocyte sedimentation rate (what it shows and norms) [best test]

shows inflammation, norms = 0-20 mm/hr

HLA-B27 (what it shows)

shows autoimmune, spondylitis