Week 6 - Intro To Image Interpretation Flashcards
Diagnostic imaging can be essential tool to:
- facilitate diagnosis
- for research
- grade severity of disease/injury
An accurate diagnosis will always be dependent on;
Thorough history
Clinical examination
Understanding relevant anatomy and likely pathological conditions
Examples of when to image
Confirm diagnosis and extent of injury and potential complications
Uncertain diagnosis which can affect management
Treatment is unsuccessful and diagnosis is questioned
Objective assessment of pathology progression/regression
Surgical work up
Plain radiographs are used to confirm, assist or exclude diagnosis
Imaging rights for Pods under MBS
Pods In aus may refer patients via Medicare for plain radiographs of the foot, knee, leg and femur as well as US examination of soft tissue conditions of the foot
Can order CT, MRI and other imaging techniques but is expensive as not covered by Medicare
Ethical considerations
The benefit to be contained from images must outweigh the risk of tissue damage from the technique - radiation: plain radiography, CT, fluoroscopy and NM
Only order imagines if the outcome of the plain radiography has the potential to alter treatment
There is a cost to any imaging technique
-financially
- radiation exposure
- ALARA
Health stewardship
Any practitioner who has the ability to refer directly for imaging must have a sufficient level of knowledge to be able to request appropriate investigations and understand the fundings of reports as we,L as the ability to act appropriately on the findings
What imaging modality do I choose
Conventional radiography (CR) remains the most commonly performed imaging investigation for assessment of the MSK system. Generally indicated in all fractures and dislocations and are sufficient for diagnosis in the majority of cases
CR can only identify general bone conditions, bone tumours and other focal bone lesions when comboned with clinical history and physical examination
A major limitation of CR is insensitivity go early bone changes in conditions such as osteomyelitis inflammatory arthritides and stress fractures
Appropriateness criteria for imaging - ACR
Developed by American college of radiology have specifically been developed to assist clinicians in selecting the best type of imaging study for the identification of a suspected pathology or which imaging type may be indicated across a diverse range of clinical scenarios
The appropriateness criteria are based on the supporting evidence base and expert consensus and they provide specific recommendations on which projections should be requested and the typical radiological features associated with specific pathologies
Many appropriateness criteria have been incorporated into commercially available electronic health record, referral and payment systems in an attempt to reduce unnecessary imaging referrals
To obtain the best result from images
Provide enough clinical and supporting information to assist imaging examination
- identify the specific anatomy involved in the pathology
- offer some guiding differential diagnosis for the radiographer so you are on the same page
- provide some clinical notes so appropriate imaging sequence can be obtained
MRI
Beneficial for soft tissue analysis
MRI sequences
An MRI pulse sequence is a programmed set of changing magnetic gradients
Different pulse sequences allow the radiologist to image the same tissue in various ways and combinations of sequences reveal important diagnostic info about the tissue in question
MRI sequences - T1 and T2
T1 weighted - fat bright, fluid dark, bones bright
T2 weighted image - fat intermediate-bright, fluid bright, bone intermediate
MRI intensity
White areas = high signal intensity
Black areas = low signal intensity
MRI Reports will describe the appearance of the intensity of the signal by relative terms that is, how bright the signal appears relative to a comparative sits and it may be described as: hyperintense (brighter), hypointense (darker) or isointense (same brightness)
MRI T1
T1 weighted = most anatomical of images and particularly useful for demonstrating trabecular detail and oasesous pathology including osteomyelitis
How will MRI reports describe the appearance of the intensity of the signal by relative terms
how bright the signal appears relative to a comparative sits and it may be described as: hyperintense (brighter), hypointense (darker) or isointense (same brightness)
