Acceso abierto

Non-contrast ultrasound assessment of blood flow in clinical practice

, ,  y   
30 nov 2024

Cite
Descargar portada

Fig. 1.

Waveforms of arterial blood (A) flow towards the transducer, and venous blood (B) flow away from the transducer. The waveforms illustrate a higher frequency (4 cycles per second) of the arterial flow (a positive shift) than the venous flow frequency (2 cycles per second) within the same period. This is further illustrated (C, D) using metal spring diagrams where there are more compressions on the spring pattern representing flow towards the transducer and more regions of rarefactions on the spring pattern representing flow away from the transducer
Waveforms of arterial blood (A) flow towards the transducer, and venous blood (B) flow away from the transducer. The waveforms illustrate a higher frequency (4 cycles per second) of the arterial flow (a positive shift) than the venous flow frequency (2 cycles per second) within the same period. This is further illustrated (C, D) using metal spring diagrams where there are more compressions on the spring pattern representing flow towards the transducer and more regions of rarefactions on the spring pattern representing flow away from the transducer

Fig. 2.

Sonograms of the right internal (ICA) and common carotid arteries (CCA) showing spectral Doppler waveforms and measurements of the PSV and EDV within the lumen of the vessels – images by E.A.
Sonograms of the right internal (ICA) and common carotid arteries (CCA) showing spectral Doppler waveforms and measurements of the PSV and EDV within the lumen of the vessels – images by E.A.

Fig. 3.

A simple chart showing the various Doppler modalities with their corresponding velocity ranges. CDI and PDI have filtered out clutter artefacts within similar velocities as microvascular velocity flow signals. McVI can separate the clutter from microvascular flows
A simple chart showing the various Doppler modalities with their corresponding velocity ranges. CDI and PDI have filtered out clutter artefacts within similar velocities as microvascular velocity flow signals. McVI can separate the clutter from microvascular flows

Fig. 4.

A 7 mm polyp in the gallbladder of a 42-year-old male. Color Doppler with a low PRF setting revealed no vascularity evidence. Microvascular imaging revealed a feeder vessel from the gallbladder wall into the polyp. Dual-display B-mode-B-flow ultrasound also revealed subtle evidence of the feeder vessel (adjacent to the caliper) – images by E.B.
A 7 mm polyp in the gallbladder of a 42-year-old male. Color Doppler with a low PRF setting revealed no vascularity evidence. Microvascular imaging revealed a feeder vessel from the gallbladder wall into the polyp. Dual-display B-mode-B-flow ultrasound also revealed subtle evidence of the feeder vessel (adjacent to the caliper) – images by E.B.

Fig. 5.

Abnormally thickened endometrium (18.6 mm anteroposteriorly) in a 12-year-old female with symptoms of abnormal uterine bleeding. PDI and CDI showed some myometrial vessels with no significant flow evidence in the endometrium. B-flow showed the myometrial vessels with tiny vessels within the endometrium. McVI revealed evidence of endometrial hypervascularity that was not evident on CDI/PDI – images by E.B.
Abnormally thickened endometrium (18.6 mm anteroposteriorly) in a 12-year-old female with symptoms of abnormal uterine bleeding. PDI and CDI showed some myometrial vessels with no significant flow evidence in the endometrium. B-flow showed the myometrial vessels with tiny vessels within the endometrium. McVI revealed evidence of endometrial hypervascularity that was not evident on CDI/PDI – images by E.B.

Summary of various non-contrast ultrasound flow modes_ Microvascular imaging (McVI) nomenclatures used by different ultrasound manufacturers (listed alphabetically)

Company Canon Medical Systems General Electric Healthcare Hitachi Medical Systems Philips Healthcare Samsung Medison Siemens Healthineers
Brand name Superb Microvascular Imaging MicroVascular Imaging eFlow MicroFlow Imaging MicroVascular Flow Slow Flow
Acronym SMI MVI MFI MV Flow -

Summary of various non-contrast ultrasound flow modes

Flow mode CDI PDI ADF McVI B-flow
Working principle Doppler Doppler Doppler Doppler Non-Doppler
Generation 1st Gen. 2nd Gen. 3rd Gen. 3rd Gen. 3rd Gen.
Major pros

Adjustable Doppler box

Provides flow directionality information

Available on all ultrasound machines and probes

Better penetration than MVI and B-flow

More sensitive than CDI

Adjustable Doppler box

Available on all ultrasound machines and probes

Better penetration than MVI and B-flow

Suitable for examining the fetal placental vessels and fetal heart chambers

Shows flow directionality

The most sensitive (non-contrast) flow mode to microvascularity

Can prevent the need for other invasive or radiation examinations

Not angle-dependent

Sensitive to slow flows

Can visualize tiny vessels

Provides flow information of the entire ultrasound screen; no Doppler box is required

Major cons

Filters out microvascularity

Angle dependent

Prone to aliasing

Filters out microvascularity

Focuses more on flow intensity over velocity

Least sensitive to microvascularity

Provided by only one manufacturer

Doppler box is limited in size.

Only available on high-end ultrasound machines

Not available on all ultrasound probes

Less sensitive than CDI and PDI in deeper organs

Focuses more on flow intensity over velocity

No information on flow directionality

Provided by only one manufacturer

It is not currently available on all ultrasound probes

Less sensitive than CDI and PDI in deeper organs

Focuses more on flow intensity over velocity

Idioma:
Inglés
Calendario de la edición:
4 veces al año
Temas de la revista:
Medicina, Ciencias médicas básicas, Ciencias médicas básicas, otros