Bone Path 3 Final

Question 1

What provides a general direction for clinicians when deciding to take images or not?

Answer 1

Mercy guidelines.

Question 2

What 2 questions should be asked before ordering imaging?

Answer 2

1. Will it affect diagnositic certainty about a DDX (if so how much). 2. will it change my diagnostic thinking enough so that it will significantly affect my choice of treatment.

Question 3

Name the things people can have that might be a high risk group for low back pain when radiographs have a high probability for positive findings?

Answer 3

Patients over 50, significant tauma, neuromotor deficits, unexplained weight loss, suspicion of ankylosing spondylitis, drug or alcohol abuse, history of cancer, corticosteroid use, fever over 100, DM/and or hypertension, lack of improvement, patients seeking compensation for back pain, dermopathy, cachexia, deformity and immobility, lymphadenopathy, elevated ESR, elevated acid or akaline phasphatase, positive Rheumatoid factor, positive HLA-B27, serum gammopathy.

Question 4

CT scans are highly sensitive and specific for what?

Answer 4

degenerative spinal stenosis.

Question 5

Why do we not take radiographs to screen for the clinically silent conditions?

Answer 5

A good history and physical should reveal red flags that place the person in the high risk groups so radiographs will then be taken.

Question 6

Name 4 nonclinical reasons people take radiographs?

Answer 6

financial gain, force of habit, medicolegally advantageous, patient education.

Question 7

low back pain that persists for how long should then be x-rayed?

Answer 7

7 weeks.

Question 8

How much bone destruction is needed to be visualized on x-ray and bone scan?

Answer 8

x-ray- 30-50%, bone scan- 3-5%. So radiographs are very specific and less sensitive and bone scans are very sensitive and not specific.

Question 9

Name 3 areas radiographs are used for biomechanica and posture?

Answer 9

scoliosis, spinogrpahic analysis, functional radiography.

Question 10

Are full spine radiographs for scoliosis diagnosticly effective and have an acceptable risk/benefit ratio?

Answer 10

Yes.

Question 11

Is spinographic analysis clinically justifiable?

Answer 11

No.

Question 12

How clinically significant are functional radiographs (flexion/extension, lateral bending)?

Answer 12

New research shows they are probably not that good.

Question 13

Should degenerative processes be monitored with radiographs?

Answer 13

No since it will not alter the treatment, besides with stenosis.

Question 14

CT is particularly useful in evaluating what?

Answer 14

apophyseal joint degeneration, bone hypertorphy, spine fx/dislocations, infections, bone neoplasms, complex congenital anomalies, spinal stenosis, metabolic disease, post operative spines, HNP.

Question 15

When is CT superior to MRI and when is MRI superior to CT?

Answer 15

CT is superior in evaluating bone changes and MRI is superior in evaluating soft tissue changes.

Question 16

What are the indications for CT?

Answer 16

spinal stenosis, bone/joint/disc disease, complex anomalies, spinal trauma.

Question 17

What are the indications for CT with myelography?

Answer 17

thecal sac, nerve root (if MRI is not available) MRI IS BETTER.

Question 18

What are the indications for MRI?

Answer 18

direct visulaization of soft tissues, joint and disc diseases, sensitive to bone marrow pathologies.

Question 19

What are the indications for MRI with gadolinium?

Answer 19

postoperative fibrosis (since scars will have increase in vascularization), recurrent HNP.

Question 20

What are the indications for radionuclide studies?

Answer 20

to identify metabolic activity benign vs. aggressive, acute vs chronic, mets and infections.

Question 21

What are the indications for diagnostic ultrasound?

Answer 21

indirect causes of back pain like: AAA, pelvic neoplasms, neonatal spinal evaluations.

Question 22

What is the best test for herniated nucleus pulposus?

Answer 22

MRI.

Question 23

What is the best test for spinal stenosis?

Answer 23

CT or CT with myelography.

Question 24

What is the best test for spondylolisthesis?

Answer 24

plain film.

Question 25

What is the best test for inflammatory arthropathies?

Answer 25

Plain film.

Question 26

What is the best test for trauma?

Answer 26

CT.

Question 27

What is the best test for infections?

Answer 27

MRI.

Question 28

What is the best test for instability?

Answer 28

plain film.

Question 29

What has replaced myelography?

Answer 29

MRI and CT.

Question 30

What 2 things will MRI be really good at imaging?

Answer 30

Infection and neoplasms.

Question 31

How can you distinguish between post operative fibrosis pain or pain from a recurrent disc herniation?

Answer 31

Use Gadolinium with the MRI. Fibrosis will take in the contrast within 15 minutes and disc herniations will only take in a little contrast after 30 minutes.

Question 32

what is the main reason now days for using discography?

Answer 32

used as a provocative test.

Question 33

What will hot spots on a bone scan mean?

Answer 33

Areas of increased blood flow due to increased metabolism.

Question 34

What are SPECT bone scans used for?

Answer 34

Exact location of a lesion.

Question 35

When should bone scans be used?

Answer 35

after less expensive imaging and with red flags.

Question 36

When would you use ultrasound to image the spine?

Answer 36

Only with neonates.

Question 37

Why would you take a Ct or an MRI of the brain?

Answer 37

CT- SAH, acute subdural. MRI- MS, recent infarct, tumors, aVM's, cerebral aneurysms.

Question 38

Why would you take a CT or an MRI of the orbits?

Answer 38

CT- graves, pseudotumors, foreign bodies, Fx. MRI- secondary evaluation of masses, tumors of optic nerve.

Question 39

Why would you take a CT or an MRI of the head and neck?

Answer 39

CT- tumors and adenopathy. MRI- parathyroid tumors, problem solving after CT.

Question 40

Why would you take a CT or an MRI of the chest?

Answer 40

CT- CXR abnormalities, CA, fibrosis, PE. MRI- problem solving after CT.

Question 41

Why would you take a CT or an MRI of the abdomen?

Answer 41

CT- liver diseases/tumor, lymphoma, pancreatic CA, renal colic. MRI- problem solving after CT.

Question 42

Why would you take a CT or an MRI of the pelvis?

Answer 42

CT- appendicitis and diverticulitis. MRI- uterine problem solving after US and prostate cancer staging.

Question 43

Why would you take a CT or an MRI of the bones?

Answer 43

CT- Fx. MRI- tumors, osteomyelitis, AVN, stress Fx, Marrow changes.

Question 44

Why would you take a CT or an MRI of the joints?

Answer 44

CT- loose bodies, post-arthrogram studies. MRI- most problems of the shoulder, hip, knee ankle and wrist.

Question 45

Why would you take a CT or an MRI of the spine?

Answer 45

CT- degenerative stenosis. MRI- disc disease, bony metastasis, any cord pathology.

Question 46

What are the 3 advantages of plain film radiography?

Answer 46

cost effective, minimal radiation, widely available.

Question 47

Contrast resolution of CT is how much better than plain film radiopgraphy?

Answer 47

100 times better.

Question 48

Will CT have a film based receptor?

Answer 48

No. Only numerical data is collected by a photon detector cell that is placed around the patient has the x-ray part rotates around the patient.

Question 49

CT slices can be what sizes?

Answer 49

0.5m-10mm thick.

Question 50

How much can the CT machine be angled?

Answer 50

15-30 degrees.

Question 51

Typically what type of images are produced with CT?

Answer 51

axial images. Other types will have a decreased detail.

Question 52

CT image is made up of a _____ and each part of this is known as ______.

Answer 52

matrix , voxel.

Question 53

What are the 3 dimesions of a voxel?

Answer 53

length, width, depth.

Question 54

what is a pixel?

Answer 54

a two dimensional representation of a voxel which is length and width.

Question 55

What are the different types of units assigned to each voxel?

Answer 55

Hounsfield units from -1000 to 1000.

Question 56

What will bone and air be in hounsfield units?

Answer 56

bone- 1000. Air- -1,000

Question 57

What are the 2 types of contast or windows used with CT?

Answer 57

1. Bone window- better to see fine detail of bone (cortex and medullary bone are distinctly different). 2. soft tissue window- better for soft tissue (cortex and medullary bone have similar densities.

Question 58

What are the contraindications of CT?

Answer 58

metallic objects near by can create artifacts. Radiation, claustrophobia and sensitivity to iodine contrast.

Question 59

When would CT be better than MRI for infections?

Answer 59

with cortical involvment, but MRI is better with medullary and soft tissue invovlement.

Question 60

Why is CT better for chest and abdomen than MRI?

Answer 60

faster and less motion artifacts.

Question 61

Would you use MRI or CT for sinuses?

Answer 61

CT.

Question 62

What will a CT myelogram look like?

Answer 62

like a soft tissue density with white contrast around the cord.

Question 63

What has better soft tissue contrast CT or plain film radiography?

Answer 63

CT.

Question 64

How do you control contrast with CT?

Answer 64

electronic manipulation of the digital info like using different windows.

Question 65

What are the disadvantages of CT?

Answer 65

relatively high radiation dosage, high cost, reformatted images not as good as original.

Question 66

What is the cage used to sheild extraneous radiofrequencies from MRI machines?

Answer 66

Faraday cage.

Question 67

The greater the ____ the better the image with MRI?

Answer 67

magnetic strength.

Question 68

What do you need to do with an MRI magnet to maintain its magnetism and create a homogenous field?

Answer 68

Keep it cooled.

Question 69

What will the radiofrequency do for MRI?

Answer 69

knock the neclei out of alignment so they can re-align.

Question 70

What is the spin density?

Answer 70

The number of hydrogen protons in tissues being imaged.

Question 71

How can you tell the difference between T1 and T2 MRI's?

Answer 71

T1- fat will be white. T2- water will appear bright.

Question 72

What will ligaments and tendons look like on T1 and T2 images?

Answer 72

both will be dark gray or black.

Question 73

What will cortical bone look like with T1 and T2 MRI images?

Answer 73

black.

Question 74

What is a high signal with MRI and what is a low signal?

Answer 74

White is high black is low.

Question 75

T1 is used to better visualize what?

Answer 75

fat, precise anatomy, medullary bone, spinal cord, low signal bone, CSF intermediate.

Question 76

T2 is used to better visualize what?

Answer 76

water, discs,

Question 77

What has better detail T1 or T2?

Answer 77

T1.

Question 78

What will the CSF look like with a proton density MRI?

Answer 78

Same as cord.

Question 79

Gadolinium is only used with what type of MRI?

Answer 79

T1 images before and after.

Question 80

What are the contraindications for MRI?

Answer 80

during first trimester of pregnancy, over 300 lbs, ferromagnetic artifacts, surgical clips, pacemakers, cochlear implants.

Question 81

What are the limitations of MRI?

Answer 81

claustrophobia, have to hold still for 30 min to 1 hour, loud tapping noises.

Question 82

Myelography is not used as much with plain film radiography anymore, but when is it used?

Answer 82

With CT to visualize indirectly a lesion in the spinal canal.

Question 83

Myelography has been largely replaced by what?

Answer 83

MRI.

Question 84

What are the indications for myelography?

Answer 84

When CT or MRI is not available and can be used with CT presurgically.

Question 85

When is CT-myelography the gold standard?

Answer 85

pre-surgically for spinal stenosis.

Question 86

what are the disadvantages of Myelography?

Answer 86

Pt needs to be monitored for 3 hours after, infection risk, invasive.

Question 87

What do radionuclides do with nuclear medicine?

Answer 87

They emit gamma radiation as they undergo radioactive decay.

Question 88

What is the most commonly used radionuclide used with nuclear medicine?

Answer 88

technetium-99.

Question 89

What is scintigraphy?

Answer 89

a three phase scan commonly employed.

Question 90

What are the 3 phases of scintigraphy?

Answer 90

first- flow phase, second- blood pool, third- delayed or bone scan phase.

Question 91

What type of sensitivity and specificity will bone scans have?

Answer 91

high sensitivity and low specificity.

Question 92

Bone scan will uptake radionuclides when?

Answer 92

tumors, infections, acute Fx, stress Fx.

Question 93

What are the advantages of bone scans?

Answer 93

evaluate entire body, very sensitive, only need 3-5% bone destruction to been seen.

Question 94

What is discography?

Answer 94

injection of radiopaque contrast agent into the IVD as a provocative test and may demostrate dessicated discs and herniated discs.

Question 95

What is SPECT?

Answer 95

Like a bone scan, but offers multiple imaging planes like CT.

Question 96

What are the benefits of SPECT?

Answer 96

better localization of a lesion.

Question 97

What is PET?

Answer 97

positron emission tomography.

Question 98

What is PET used for?

Answer 98

to find soft tissue tumors like in lymph nodes, good for tumor grading, and used to monitor treatment success.

Question 99

PET has a greater resolution than what?

Answer 99

SPECT or scintigraphy.

Question 100

What is the major disadvanatge of PET?

Answer 100

high cost and low availability.