US QUIZ

1- linear

2- curvilinear

3- phased array

LINEAR PROBE

high frequency

linear footprint

shallow structures

GOOD FOR BREAST AND CHEST IMAGING

• Frequency affects penetration.

• Frequency also impacts velocity scales (Nyquist limit & Doppler equation in Colour Doppler).

The Phased/ Sector array transducer

Low frequency

Narrow footprint

Deep structures

FOR BREAST AND CHEST US

• Larger body habitus → need greater penetration, lower frequency.

• Phased array useful, incl. for biopsies.

The curvilinear ultrasound transducer

low frequency

wide footprint

deep structures

Ultrasound probe movements and manipulation

GAIN VS TGC

• Overall Gain – adjusts the brightness of the entire image by amplifying returning echoes uniformly, affecting the whole field of view.

• Time Gain Compensation (TGC) – selectively amplifies echoes at different depths, compensating for attenuation so that deeper structures appear with similar brightness to superficial ones.

• Function – optimises image quality and contrast without altering the actual transmitted ultrasound beam or patient exposure.

Power Doppler Mode

• -PD is more sensitive than color Doppler and is used to detect low flow states such as venous flow in the thyroid or testicles

• Displays the amplitude (strength) of blood flow signals rather than velocity or direction.

• More sensitive to low-velocity or small vessel flow than colour Doppler.

• Does not provide directionality of flow, but reduces angle dependency and is less affected by aliasing.

7. Modifications and Limitations of the

abdomen ultrasound

Exam components may require flexibility in order and patient positioning.

Recognition of anatomy, orientation, respiration effects, gas, and fluid pockets in real-time.

Recognise when modifications are needed.

Advantages of Breast and Chest

ultrasound

Rapid *contralateral & dynamic** assessment

* Non-invasive, portable, inexpensive

* No claustrophobia, safe with pacemakers/metal

* Guides procedures, repeatable for monitoring

* Real-time imaging

Limitations of Breast and Chest ultrasound

• Deeper structure are still difficult to visualize

• Error of Sonographer with ultrasound machine interobserver variability

• Operator dependent

• Competition of medical advancements and technology with interventional

procedures and other modalities such as CT and MRI

• Interventional procedures and invasive surgical examinations superiority

Selection of transducers and image

parameters for Breast and chest ultrasound

hockey stick transducer

High frequency greater resolution

• Small footprint

• Superficial structures and vessels

• Chest or Breast lump

Breast ultrasound pitfalls and problems

with solutions

• Lesion not visualised → poor resolution (freq/shape/focus), poor positioning, isoechoic to tissue.

• Correlation issue → cannot match with mammo/MRI/CT/clinical finding.

• Indeterminate mass (solid vs cystic).

• Techniques → harmonics, colour, adjust settings, patient reposition.

• Pitfalls → small posterior cysts (↓ enhancement), reverberation mimicking debris, Cooper’s ligament shadowing, accessory axillary tissue (matches glandular echo).

• History important → lactation may show milk-filled ducts (not tumour).

Cooper’s ligaments: are connective tissue in the breast that help maintain

structural integrity, can be seen as thin white curvilinear lines and cause

artificial shadowing and this artefact can be reduced with compression

• Tissue Harmonic imaging can provide images of higher quality

• Harmonic signals are generated differently and lead to higher contrast resolution

• Harmonics can increase real echoes and can reduce artefactual echoes

Awareness of Grading, Staging and Survival rate of

breast cancer and types of non-invasive breast cancer

• Grading → histological features

• Staging → size & spread (Stage 1–4)

• Survival rate → % reaching survival period

• Non-invasive BC types:

  • Intraductal carcinoma

  • Comedo carcinoma

  • Intraductal & LCIS

  • Papillary carcinoma

  • LCIS

Breast biopsy and some interventional

procedures

• Hook-wire → pre-op, ultrasound-guided lesion localisation for surgery

• FNA Fine Needle Aspiration→ sample tissue from solid lesion or aspirate cystic fluid

• Core biopsy → gun needle (variable throw) or vacuum-suction probe

Breast ultrasound implants and the male breast

Augmented breast:

• Reasons for US: routine follow-up, palpable mass, implant concerns (rupture, thickening, capsular fibrosis)

• Examine breast tissue over implant + implant

• Implant appears smooth, echogenic balloon with anterior reverberation artefacts

Male breast:

• Usually exclude malignancy (rare, prognosis like females, more chest wall invasion)

• Gynecomastia → common pathology, breast enlargement

Chest ultrasound

 Biopsy of chest wall, mediastinal and peripheral lung masses

• Diagnostic and therapeutic drainage of pleural fluid collections and

• Assessment of soft tissue masses of the chest

 aid in the detection

of lymphomas, retrosternal thyroids, dermoid cysts or aortic aneurysms with

this ultrasound chest approach

CHEST US INTERVENTION

• Diagnostic and therapeutic drainage of pleural fluid collections

• Moveable strands, fibrinous strings and septations are typical of

inflammatory effusions.

• Ultrasound can detect nodular metastases not seen in radiographs

Transabdominal US

A transabdominal ultrasound is conducted with a full bladder, using a 3.5-7MHz curvilinear probe over the abdomen

The patient is in a supine position

The bladder filling allows for the complete penetration of sound waves to the posterior pelvic organs while simultaneously

displacing the bowel laterally

A transabdominal ultrasound is a complete scan when transvaginal contraindications are present. They include:

 Paedatric age group

 Patients with no history of vaginal intercourse

 Vaginismus

 Significant vaginal atrophy

 Vaginal obstruction

 Recent vaginal surgery

 When a patient denies consent

 In obstetrics: premature rupture of membranes, due to risk of introducing infection and bleeding associated with known placenta

previa

Transvaginal US

A transvaginal ultrasound is conducted with a 5-12 MHz, narrow

transvaginal probe

It is inserted into the vagina and then carefully moved by the

sonographer to obtain the images

The patient can be lying in the supine position with a bolster under the

pelvis to allow for free movement of the probe

Empty bladder

Generally, when there are no contraindications both a transabdominal

then transvaginal scan is completed, in the same visit

Translabial

ultrasound

A translabial ultrasound is completed with either a curvilinear or linear array

transducer which is placed over the perineum and not inserted into the vagina

This allows for high resolution imaging of superficial structures with a wide field of view

Empty bladder

Recent advances in imaging for prolapse show translabial ultrasound as way to dynamically assess for the movement of the uterus, bladder, bowel in relation to

each other and the rectum using dynamic real time assessment

We can use transvaginal ultrasound to manually assess ovarian and uterine mobility and

differentiate between the origin of a mass

We can ask the patient to cough, to bring up the ovary if its obscured by bowel or gas

We can provide comfort to the patient

There is no ionizing radiation exposure associated with ultrasound imaging

Limitations of Breast, Chest and Reproductive

ultrasound

•

Deeper structure are still difficult to visualize

• Error of Sonographer with ultrasound machine interobserver variability

• Operator dependent

• Competition of medical advancements and technology with interventional

procedures and other modalities such as CT and MRI

• Interventional procedures and invasive surgical examinations superiority

The Endocavitary probe

• Designed for internal imaging (e.g., transvaginal, transrectal).

• Higher frequency → better resolution, shallower penetration.

• Provides close proximity to organs for detailed assessment.

linear probe chest n breast imaging mghz selection

 Minimal glandular breast tissue15-7MHz or

• Enlarged breast glandular tissue 10-7MHz

Advantages of MSK ultrasound

• Real time assessment (joint crepitus)

• Dynamic examination (specific motion induced pain, discomfort)

• Higher spatial resolution images of superficial soft tissue anatomy than MRI

• Allows for rapid contralateral examination (limb comparison)

• Non invasive

• Portable (availability)

• Relatively inexpensive compared to other modalities (MRI, CT)

• No claustrophobia

• Practical and rapid method of obtaining images

• Safe in patients with pacemakers and metal artefacts

• Guide procedures (Injections, aspirations, biopsy)

The high frequency linear array transducer

• High frequency 17-5MHz

• Greater resolution

• Superficial structures

• Linear array transducer

Power Doppler (PD) Mode in MSK

ultrasound

• PD is more sensitive than color Doppler and is used to detect blood flow or

vascularity in tendons

• Increased PD signals are associated with inflammatory conditions.

• Doppler signals are easily obliterated with probe pressure or when the

tendon is stretched

MSK ultrasound techniques to aid in

artefact prevention including anisotropy

• Thick gel or stand off pad (not contaminated)

• Spatial compounding

• Beam steering

• Panoramic imaging

Spatial compounding in MSK ultrasound

Greater beam _______

Greater beam reduces the frame rate

Beam steering in MSK ultrasound and Anisotropy

manual beam steering. This technique involves tilting the probe over the area of

interest to make the ultrasound beams approach being perpendicular to the needle

and increasing signal as seen above.

• A false hypoechogenicity of a structure due to obliquity of ultrasound beam

• One of the most common artifacts especially in MSK ultrasound.

• To minimize the artifact, the MSK structure should be scanned

perpendicular to the ultrasound beam (parallel to the transducer face).

• This can be achieved by “heel-toeing” the transducer.

MSK ultrasound artifacts and pitfalls

Shadowing

• Enhanced through-transmission

• Comet-tail artifact

• Refraction

• Speed or sound artifact

• Beam width artifact

• Motion artifact

• Ensure comparison with contralateral side

• Don’t compress and obliterate small fluid collection or tears and

• Examine dynamically and at all angles

Ultrasound characteristics of a true cyst in neck and

associated structures sonography

• Anechoic (isoechoic)

• Posterior enhancement

• Posterior wall definition

• Side wall definition

• No internal echoes

Neck ultrasound: common cystic locations and other

regions of patholog

 Thyroglossal duct cysts- most commn

• Brachial cleft cyst

• Miscellaneous cystic masses and

Other common pathology regions:

• non-cystic masses

• Lymphatic nodes

• Salivary glands

Ultrasound features in assessing Thyroid nodule –a

set of different case studies

 Co-existing multilnodularity

• Echogenicity compared with normal thyroid tissue

• Peripheral anechoic halo

• Internal consistency

• Surrounding structures

• Margination

• Calcification

• Vascularity

Ultrasound features that favour a benign lesion in the

neck region

 Co-existing multilnodularity

• Echogenicity compared with normal thyroid tissue

• Peripheral anechoic halo

• Internal consistency

• Surrounding structures

• Margination

• Calcification

• Vascularity

Ultrasound features that favour a malignant lesion in

the neck region

Co-existing multilnodularity

• Echogenicity compared with normal thyroid tissue

• Peripheral anechoic halo

• Internal consistency

• Surrounding structures

• Margination

• Calcification

• Vascularity

The high frequency linear array

transducer for Vascular ultrasound

• Transducer frequency is dependent on patient body habitus for example a

carotid examination:

• Thin neck 5-7MHz or

• Thick larger neck 10-7MHz

The Doppler shift using the velocity of

blood

• Best Doppler angle = parallel (0°) to us probe→ accurate measurement

• >25–30° → underestimation

• 90° (perpendicular) → cos90=0 → no flow detected

 Pulse Wave (PW) Doppler in

Vascular ultrasound

• PW Doppler → measures velocity at a single point

• Sample gate specifies location (marked by 2 horizontal lines)

• Limitation → aliasing artefact

• PW Doppler limit = Nyquist limit → beyond this → aliasing

• Not suitable for speeds >200 cm/s

Continuous Wave (CW) Doppler

• CW Doppler is very similar to PW Doppler except it does not alias

• And can detect very high velocities (greater than 1000cm/second).

• Optimal choice for measuring high-velocity applications such as valvular

stenosis and regurgitation.

• CW Doppler does not rely on a sample gate to measure a single point

• Therefore what you will see will be the maximum velocity of flow detected

along the cursor line. This is a pro and a con.

• It is a pro because you don’t have aliasing and can detect high velocities

• It is a con because you don’t know exactly where that velocity is coming

from on the cursor.

• Wall filter → removes low-velocity signals / ↓ artefacts

• Steer → adjust colour box to improve angle

• Angle correction → for PW, corrects sample gate angle

Vascular ultrasound techniques to aid in artefact prevention

including aliasing

Aliasing:

• Most common Doppler artefact → occurs when signal undersampled

• Solution → ↑ pule repetition freq PRF

• Limited by Nyquist limit

Other optimisation:

• Compound imaging → multiple sightlines → better plaque definition, ↑ contrast, improved imaging through calcific plaques