Contrast Enhanced Ultrasound“Imaging Without the Risk”

Muhammad Hasan, MBBCh, RPVI, RVTMiami Cardiac & Vascular Institute

Baptist Hospital of Miami, Miami, FL

Disclosures

• I have no affiliations to disclose

Ultrasound Imaging – The Basics

• Transmit high frequency Sound Pulses.• Reflected echoes from each tissue interface are

collected to form frames that display as dynamic real time imaging.

Contrast Enhanced Ultrasound CEUS• Use special application – Pulse Inversion PI• Pulse Inversion PI is a form of digital subtraction

ultrasonography that suppress imaging of soft tissue and enhance imaging of MBCAs.

Sum

Contrast Enhanced Ultrasonography

Before Injection After Injection

Microbubble Contrast Agent MBCA• 1960’s – Agitated air in saline bubbles (Less

stable)• 1994 Sonovist – Berlin (More stable – 10 min)• 2001 – Sonovue (Bracco International) approved

by the European Commission• 2014 Lumason – FDA approved• 2016 Lumason - Centers for Medicare & Medicaid

Services (CMS) Approved Coverage and Coding for Abdominal Ultrasound with Contrast applications.

Microbubble Contrast Agent MBCA• Lumason (Sulfur Hexafluoride lipid-type A microspheres)

• Prepared ingredient contains thousands of very small low solubility microbubbles (1-7 µm in diameter)

• Microbubbles will expand and contract while interacting with the transmitted ultrasound beam.

• Reflected echoes from the microbubbles in blood pools are displayed on a dynamic real time imaging

LUMASON® - Contents of a Kit

u Lumason vialu 5 mL Saline

prefilled syringe and its plunger

uMini-spike

LUMASON® - Reconstitution

Microbubble Contrast Agent MBCA• Injected intravenously using a 3-way stop cock

(straight line) in 2.4 mL dose flushed by 5 mL Saline (lateral line).

• Microbubbles are inert gas encapsulated in a lipid/protein shell.

• Intact Passage through heart and lungs.• Life span of approximately 10 minutes.• When broken – shell metabolized in liver and gas

exhaled by lungs

Lumason

Saline Flush

Inject in straight lines (using a 3-way stop cock)

Protocol Steps• Perform conventional ultrasound protocol• Identify anatomy to contrast• Apply contrast setup in equipment• Inject contrast, flush with saline, start timer,

record imaging acquisitions

Microbubble Contrast Agent MBCA• Relatively very safe.• No nephrotoxic/hepatotoxic side effects.• Adverse reaction is rare (0.0086%) – headaches

and nausea.

CEUS Applications• Liver imaging to characterize focal lesion(s) in

adult and pediatric patients.• Echocardiography in with suboptimal conventional

imaging/to enhance certain pathologies.• Pathological conditions affects circulatory system.

CEUS Applications• F/U - Renal artery stent Patency• Renal Perfusion• AAA with ulcerated thrombus• ICA in-stent re-stenosis

CEUS Applications• F/U EVAR placement/revision• Renal Perfusion

Endovascular Aortic Repair EVAR

Abdominal Aorta Stent Graft• Patients undergone endovascular aortic repair

EVAR require lifelong surveillance and follow up• Repetitive CTA associated with cumulative

radiation exposure – multiple doses of nephrotoxic contrast agents.

• CEUS – An Emerging alternative with high sensitivity and specificity in diagnosing endoleaks

CEUS – Timing is everything• Enhancement/washout of liver and kidney masses.• Enhancement of aortic stent graft and leaks into

the excluded aneurysmal sac.• Inject contrast, flush with saline, start timer,

record imaging acquisitions

Definitions – Contrast Timer

CEUS – Timing is everything• Type 1 and 3 leaks will enhance at the same time

as the stent lumen• Type 2 leaks enhancement will be delayed by up

to 6-15 seconds.• Delayed enhancement may be longer with reduced

cardiac output, size of the feeder vessel and flow magnitude.

Is contrast-enhanced ultrasound (CEUS) superior to computed tomography angiography (CTA) in detection of endoleaks ….

uConclusions- A total of 1773 patients were analysed from across 18

researched studies demonstrated no significant difference in detection rate of endoleak type I, II or III

- the sensitivity rate was higher in CEUS (p = 0.001)- No difference in specificity rate was noted (p = 0.28). - There was higher rate of missed endoleaks in CTA groups

(n = 12 vs n = 20).J Ultrasound. 2019 Mar;22(1):65-75. doi: 10.1007/s40477-019-00364-7. Epub 2019 Feb 15.

Conclusions/Recommendations§ CEUS should be considered as the primary

diagnostic modality in the post-EVAR surveillance when the aneurysmal sac is stable and decreasing in size.

§ CEUS cannot completely replace CTA for endoleak assessment. Once endoleaks and increase in aneurysmal size on CEUS is detected, CTA should be performed for further work-up and planning of the therapy

Thank you .. mhasan@baptisthealth.net