radiology lectures 2-4

Question 1

when to use MRI (4) vs CT (1)

Answer 1

CT- good for boney fragments & spatial resolution (fractures)

MRI
soft tissue tears/injury
occult fxs not picked up on xray/CT
edema/fluid
structural abnormalities

Question 2

MRI sequences… how do we see fat and fluid in

T1 vs. T2 vs. STIR

Answer 2

T1- fat bright, fluid dark
T2- fat bright, fluid bright, can do fat saturation
STIR- fat dark, fluid bright

T2 & STIR are fluid sensitive => good for seeing edema

Question 3

standard views for:
 long bones
 joints
 shoulder
pelvis & hips

Answer 3

long bones: 2 orthogonal view; 90 degrees from eachother
AP/laterl (for arm, forearm, thigh, leg)

joints: 3 views; AP, lateral, oblique

shoulder: 3 views; AP, y-scap & axillary
AP in IR and ER

pelvis & hips: 2 AP & frog-leg lateral

Question 4

how to read an x-ray (8)

Answer 4

1. identify normal bones
2. look for cortical continuity
3. look at alignment
4. look for any extra densities or lucencies w/i or outside bone
5. look at soft tissue for swelling or joint effusion
6. look at adjacent joints
7. compare with prior studies
8. if still concerned get CT or MRI

Question 5

3 hand arcs

Answer 5

arc I = proximal surface of: scaphoid, lunate, triquetrium
arc II = distal surface of: scaphoid, lunate, triquetrium
arc III = proximal surface of: capitate & hamate

Question 6

alignment of wrist/ hand in lateral view

Answer 6

radius, lunate, capitate & 3rd MC line up

Question 7

various ways fx show up on x-ray (6)

Answer 7

1. cortical discontinuity or deformity
2. radiolucent fx lines
3. abnormally white or dense areas = overlapping fragments
4. extra or unexplained bone fragments
5. soft tissue swelling or jt effusion
6. callus formation in healing fxs

Question 8

gamekeepers thumb
a.k.a.
what is it
complication

Answer 8

a.k.a. skiers thumb

diruption of UCL at 1st MCP joint (falling on outstretched hand with aBducted thumb

stener lesion-displacement; UCL can’t heal properly because aponeurosis blocks insertion

Question 9

posterior fat pad sign
normal anatomy on radiograph (2)
sign (1)

Answer 9

normal anatomy:

1. anterior fat pad is normally a faint line more radiolucent than adjacent muscles & runs parallel to distal humerus
2. posterior fat pad is normally pressed deep into olecranon fossa by tricep tendons and is invisible

posterior fat pad sign:
elevated anterior lucency and/or visible posterior lucency at true lat radiograph of elbow flexed at 90 deg

Question 10

hill scahs lesion
what is it/ when do we see it?
how do we best view it

bankart lesion
what is it/ when do we see it?

Answer 10

hill sachs

1. flattening of supero-lateral (posteriolateral) aspect of humeral head seen after forceful anterior shoulder dislocation
2. best seen on AP IR plain film

bankart
inferior/ anterior aspect of glenoid injured during anterior dislocation

these two are commonly seen together

Question 11

posterior shoulder dislocation
biomechanics (2)
cause
dx

Answer 11

1. humerus forced posteriorly and IR
2. anterior humeral head isimpacting posterior glenoid
3. usually caused by convulsions, rarely by trauma
4. difficult to dx by radiograph and often mis-dx as frozen shoulder or adhesive capsulitis * get CT or MR

Question 12

shoulder dislocation rates
anterior
posterior
luxatio

Answer 12

anterior- 95-97%
posterior- 2-4%
luxatio (inferior) - 0.5%

Question 13

clinical findings for RC tears
signs (3)
symptoms (2)
dx

Answer 13

signs

1. supraspinatus weakness
2. ER weakness
3. impingement

symptoms

1. over >60 yo
2. night pain

if all 3 signs are positive or 2/3 and pt > 60; chance of tear is 98%

Question 14

RC cuff tears
 most commonly affected
 where they begin
 full length extend to...
 subscap affects...

Answer 14

1. supraspin is primarily involved in most instances
2. tears usually begin at site of insertion
3. tears can extend posteriorly to infraspin & teres minor
4. subscap tendon may have isolated tear & associated with dislocation of bicep tendon

Question 15

what is subscap tendon tear associated with?
anatomy
which location

Answer 15

dislocation of bicep tendon (usually medially)

subscap tendon continues across bicipital groove as transverse humeral ligament which helps stabilize bicep tendon.

Question 16

radiographic findings of RC tears (3)

look at slides

Answer 16

1. high riding humerus
2. faceting & sclerosis in inferolateral acromion & superior aspect of greater tuberosity
3. secondary osteophytes in GH joint to maintain joint congruity

Question 17

full thickness tears of supraspinatus (4)

Answer 17

1. fully extend from bursal to articular surface
2. nonvisualization of tendon
3. fluid in expected location of tendon
4. measure AP width

Question 18

calcific tendinosis
 most common place
 what we see on radiograph
 symptoms
 radiograph we need to find it
 tx

Answer 18

1. most comon in supraspin tendon
2. tendon is thickened and heterogenous w/o discrete defects
3. subclinical -> painful
4. can be seen as low signal intensity on all MR sequences
5. treated by saline lavage

Question 19

infection
 looking for... laundry list
 when its the joint its called...
 when its the bone its called...
 how to look for it (radiologic testing)

Answer 19

looking for… soft tissue swelling, ulcers, subcutaneous air, skin thickening, cellulitis, abscess, fistulas

joint => septic arthritis
bone => osteomyelitis

MRI is most sensitive to edema or do nuclear bone scan

Question 20

approach to arthritis (ABCDES)

Answer 20

a= alignment
b= bone mineralization
c= cartilage loss
d= distribution
e= erosions?
s= soft tissue masses

Question 21

classifications of arthritis (3)

Answer 21

1. OA; primary or secondary
2. RA
3. crystal; gout

Question 22

degenerative arthritis
aka
radiologic findings
where do we commonly see DJD? where do we rarely see DJD?
does if affect more prox or distal in hands?

Answer 22

aka- OA

radiologic findings

1. loss of articular cartilage
2. joint space narrowing
3. osteophyte formation
4. sclerosis
5. subchondral cysts

occurs in WB joints (hips knees), rarely in hands or shoulders

generally more distal in hands (than RA which is proximal)

Question 23

RA
 what is it
 characterized by...
 what type of inflammation
 does it affect prox or distal more?

Answer 23

1. chronic autoimmune inflammatory disease
2. characterized by joint swelling, pain and destruction
3. synovial inflammation - synovium becomes thickened and causes erosion in bones
4. affects hands more proximally (vs. OA which is distal)

Question 24

criteria for being dx with RA (4)

score needed

Answer 24

1. based on # of jts
2. blood tests for rheumatoid factor
3. acute phase reactants (CPR &ESR)
4. duration of symptoms

score 6/10 => dx

Question 25

RA radiographic findings (5)

Answer 25

1. soft tissue swelling 2. osteoporosis 3. joint space narrowing 4. marginal erosions 5. in hands; bilateral, proximal process

Question 27

GOUT radiolgraphic features (4)

Answer 27

1. eccentric soft tissue swelling (TOPHI) 2. erosions with overhanging edges (reactive bone around tophus) 3. jt space preserved 4. erosions can be far away from joint

Question 28

bisphosphonate-related atypical femoral fx pathophysiology (2) radiologic signs (3)

Answer 28

1. med that inhibits bone resorption by supressing osteoclasts => increased bone mineral density 2. this suppresses bone turnover & remodeling & healing of microinjury radiologic signs 1. lateral cortical thickening (transverse fx) 2. lack of comminution 3. medial femoral spike; sharp medial cortical projection, typically arising from distal femoral fragment

Question 29

``` muscle attachments on pelvis iliac crest ASIS (2) AIIS greater trochanter lesser trochanter ischial tuberosity body of pubis & inferior pubic ramus ```

Answer 29

``` iliac crest- abs ASIS (2)- sartorius & TFL AIIS - rec fem greater trochanter - ERs lesser trochanter - iliopsosas ischial tuberosity- hamstrings body of pubis & inferior pubic ramus- adductors, gracilis ```

Question 30

``` stress fx class appearance 2 types ```

Answer 30

classic appearance = condensation of cancellous bone - perpendicular to long axis 2 types: fatigue= normal bone, abnormal stress insufficiency = abnormal bone, normal stress

Question 31

femoral neck stress fx who it affects most why its important imaging

Answer 31

1. commonly occurs in runners and military trainees 2. blood supply to femoral head runs thru femoral neck => AVN of head 3. need MRI or bone scan

Question 32

hip fx precautions

Answer 32

if there is a hx of trauma & high clinical concern for fx keep pt NWB until MRI (even if xray is negative)

Question 34

``` GOUT what it is primary gout secondary acute chronic places it commonly affects ```

Answer 34

due to hyperuricemia =>deposition of monosodium urate crystals primary gout = inborn error of metabolism secondary gout = disorders affecting urate metabolism (eg alcoholism) acute= swelling and pain mimicking septic arthritis chronic = tophi erode into bone, resulting in bony changes places it commonly affects= 1st MTP jt =90% olecranon bursitis