Editing Breast imaging

== '''Mammogram''' ==

** Situations where it is difficult to get images/interpret
*** <4cm breast tissue when compressed
*** Usually possible to get some images in a man, although not always, and not always useful
*** '''Sensitivity limited by breast density'''. Difficult to read in women <30yo. Useful only with high suspicion of malignancy in 30-40yo (start off with mammogram, then try MRI if too dense). Higher fat content is helpful for reading mammograms.
**** 95% sensitivity >60yo
**** 50% sensitivity <40yo
*** BIRADS classification for breast density:

**

*** Technique
**** Breast compression
***** Reduce the thickness of the tissue through which the radiation must pass
***** Separate adjacent structures
***** Improve resolution
**** Views
***** Typically mediolateral oblique (MLO) and craniocaudal (CC)
****** MLO needs to have visible pectoralis major
****** Note that the two views are not at right angles to one another
***** Magnification views to evaluate calcifications
***** Compression views to provide additional detail for mass lesions

** Suspicious findings:
*** Spiculated mass - 81% PPV

****

*** Non-calcified mass density (70% malignant if highly dense)
*** Grouped microcalcifications - likely intraductal calcifications in areas of necrotic tumours

****

*** Fine pleomorphic or linear branching microcalcifications - especially DCIS

****

** Low-energy x-ray: safe during pregnancy
** 10-15% of clinically evident breast cancers have a normal mammogram. 
** Screening mammography
*** Appears to be most effective for 60-70 year olds
***
** Interpretation

{| class="wikitable"
|'''Assessment'''
|'''Management'''
|'''Likelihood of cancer'''
|-
|Category 0: Incomplete – Need additional imaging evaluation and/or prior mammograms for comparison
|Recall for additional imaging and/or comparison with prior examination(s)
|N/A
|-
|Category 1: Negative
|Routine mammography screening
|Essentially 0% likelihood of malignancy
|-
|Category 2: Benign
|Routine mammography screening
|Essentially 0% likelihood of malignancy
|-
|Category 3: Probably benign
|Short-interval (6-month) follow-up or continued surveillance mammography
|>0 but ≤2% likelihood of malignancy
|-
|Category 4: Suspicious
|Tissue diagnosis*
|>2 but <95% likelihood of malignancy
|-
|Category 4A: Low suspicion for malignancy
|
|>2 to ≤10% likelihood of malignancy
|-
|Category 4B: Moderate suspicion for malignancy
|
|>10 to ≤50% likelihood of malignancy
|-
|Category 4C: High suspicion for malignancy
|
|>50 to <95% likelihood of malignancy
|-
|Category 5: Highly suggestive of malignancy
|Tissue diagnosis*
|≥95% likelihood of malignancy
|-
|Category 6: Known biopsy-proven malignancy
|Surgical excision when clinically appropriate
|N/A
|}

** BIRADS 3 should not be used in screening - needs further investigation, so technically a 0

** Mammogram classification - to allow detection of concordance within the triple test
*** M1: normal
*** M2: benign
*** M3: uncertain but probably benign
*** M4: suspicious and possibly cancer
*** M5: cancer
** Screening vs diagnostic mammography
*** Screening is just CC and MLO
*** Diagnostic would be where the radiologist is available and specific views are obtained to achieve better resolution on abnormalities, including magnification, compression, lateral
*** Tomography 

== '''3D mammography''' (tomosynthesis) ==

** Tomographic images reconstructed from multiple low-dose projection images - like a basic CT
** Overall dose of radiation is comparable to regular mammogram
** Gives 1mm slices
** Good at delineating small and multiple masses, microcalcifications, and distortion due to ducts and vessels
** Reduces false-positives and cancer detection

== '''Contrast-enhanced mammogram''' ==

** Injection of iodinated contrast agent two minutes prior to mammogram
** Superior accuracy to mammogram, nearing accuracy of MRI
** Expect vascular lesions such as malignancy to have contrast uptake


== '''Ultrasound''' ==

** Most useful in determining whether a lesion is solid or cystic, and for discriminating lesions in patients with dense breasts
** Not a good screening tool - '''has to be done for a targeted lesion'''
** Indications
*** Lump in pregnant/lactating women
*** Lump in patient <30yo (first-line)
*** Lump in patient >30yo (based on clinical suspicion)
*** Mammographic mass
*** Axillary assessment in patients breast cancer
*** Suspicious MMG without mass
** Findings
*** Shape - ovoid vs irregular
*** Orientation to skin (taller or wider)
*** Internal echotexture
*** Margin - circumscribed vs non-circumscribed
*** Vascularity
*** Posterior acoustic features - enhancement/variable/shadowing
** Suspicious features
*** Hypoechoic
*** Solid mass
*** Irregular border
*** Taller than wide, invading through tissue planes
*** Posterior acoustic shadowing
*** Internal vascularity
*** Lobulated
*** Associated abnormal lymph nodes in axilla

**** Short axis >3mm
**** Loss of fatty hilum
**** Asymmetrical cortical thickening
**** Calcifications
**** Round instead of oval
**** Hypervascular

** Reassuring features
*** Circular appearance (especially in younger women)
*** Containing fat, which is uncommon in breast cancers
** Classification
*** U1: normal
*** U2: benign
*** U3: uncertain but probably benign
*** U4: suspicious and possibly cancer
*** U5: cancer

== '''MRI''' ==

** Technique
*** Generally done with gadolinium contrast - detect neovascularisation 
*** Elective MRI should be performed between menstruation and ovulation to account for variation in blood flow and epithelial proliferation
*** The contrast is not safe in pregnancy
** '''Indications'''
*** Identifying primary lesions

**** Identify the primary tumour in the breast for patients that present with unknown primary axillary metastases
**** Identify the primary tumour in Paget's disease of the nipple
**** Assessing size/extent of primary tumour, especially in younger women with dense breast tissue
**** Evaluating for the presence of multifocal or multicentric cancer
**** Evaluating invasive lobular cancer where BCS is planned

*** Assessing treatment response

**** Identify extent of residual disease after lumpectomy with positive margins
**** Assess treatment response after neoadjuvant chemotherapy

*** After implants

**** Assess implant rupture
**** Assess breast when silicone injections have been used

*** Screening

**** Can be done annually in women with high risk

** Sensitivity approaching 100% for invasive cancer, and up to 92% for DCIS
** Specificity not as good as mammogram or USS - high false-positive rate
** Always do mammogram at the same time - MRI may miss some malignancies that a mammogram would detect
** Generally not recommended for women with a lifetime risk of breast cancer <15% (higher risk of false positive)
** Need to wait 19 months after surgery to differentiate cancer and scar
** Can demonstrate axillary disease, but sensitivity not adequate to replace SLNB
** Good for assessing spinal metastases

== '''CT''' ==

** Not currently done for any indications



[[Category:Breast]]