Noninvasive Estimation of the Pressure Gradient Across Stenoses Using Sonographic Contrast

In Vitro Validation

Winston W. Lien, Allen H. Lee, Yuko Kono, Greg C. Steinbach, Robert F. Mattrey

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Objective. Because velocity measurements to estimate the degree of arterial stenosis are susceptible to local and systemic factors, we aimed to investigate the feasibility of estimating the pressure gradient across a stenosis noninvasively by using sonographic contrast. Methods. Using a gravity-fed flow system, a 1:4000 dilution of a contrast agent in water was circulated through silicone tubes that had either focal or long-segment stenoses of varying severity in a water bath. We measured the cross-sectional areas of the normal and stenotic regions with B-mode sonography and the flow velocity with spectral Doppler sonography and calculated the pressure gradients across the stenoses using the empirically derived Young mathematical model and the simplified Bernoulli equation. Estimated gradients were compared with those measured manometerically. Results. Both methods yielded estimates of pressure gradients that correlated with measured gradients (r > 0.988). In focal and long-segment stenoses, the Young model yielded gradients that agreed more closely with manometerically measured values than the Bernoulli equation (±8% versus -24%-57%). Both methods were highly dependent on the ability to measure the luminal cross-sectional area. The presence of sonographic contrast in the vascular lumen highlighted the inner wall, allowing the accurate measurement of the luminal area to ±3.0%. Conclusions. The pressure gradient can be estimated across stenoses noninvasively. The Young model was more accurate than the simplified Bernoulli equation in this model using steady flow. Estimated gradients are highly dependent on the definition of the vascular lumen, a process aided by the use of sonographic contrast.

Original languageEnglish (US)
Pages (from-to)683-691
Number of pages9
JournalJournal of Ultrasound in Medicine
Volume23
Issue number5
StatePublished - Jan 1 2004

Fingerprint

Pathologic Constriction
Pressure
Blood Vessels
Doppler Ultrasonography
Water
Gravitation
Silicones
Baths
Contrast Media
In Vitro Techniques
Ultrasonography
Theoretical Models

Keywords

  • Arterial stenosis
  • Bernoulli equation
  • Flow velocity
  • Model
  • Pressure gradient
  • Young method

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

Cite this

Noninvasive Estimation of the Pressure Gradient Across Stenoses Using Sonographic Contrast : In Vitro Validation. / Lien, Winston W.; Lee, Allen H.; Kono, Yuko; Steinbach, Greg C.; Mattrey, Robert F.

In: Journal of Ultrasound in Medicine, Vol. 23, No. 5, 01.01.2004, p. 683-691.

Research output: Contribution to journalArticle

Lien, Winston W. ; Lee, Allen H. ; Kono, Yuko ; Steinbach, Greg C. ; Mattrey, Robert F. / Noninvasive Estimation of the Pressure Gradient Across Stenoses Using Sonographic Contrast : In Vitro Validation. In: Journal of Ultrasound in Medicine. 2004 ; Vol. 23, No. 5. pp. 683-691.
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abstract = "Objective. Because velocity measurements to estimate the degree of arterial stenosis are susceptible to local and systemic factors, we aimed to investigate the feasibility of estimating the pressure gradient across a stenosis noninvasively by using sonographic contrast. Methods. Using a gravity-fed flow system, a 1:4000 dilution of a contrast agent in water was circulated through silicone tubes that had either focal or long-segment stenoses of varying severity in a water bath. We measured the cross-sectional areas of the normal and stenotic regions with B-mode sonography and the flow velocity with spectral Doppler sonography and calculated the pressure gradients across the stenoses using the empirically derived Young mathematical model and the simplified Bernoulli equation. Estimated gradients were compared with those measured manometerically. Results. Both methods yielded estimates of pressure gradients that correlated with measured gradients (r > 0.988). In focal and long-segment stenoses, the Young model yielded gradients that agreed more closely with manometerically measured values than the Bernoulli equation (±8{\%} versus -24{\%}-57{\%}). Both methods were highly dependent on the ability to measure the luminal cross-sectional area. The presence of sonographic contrast in the vascular lumen highlighted the inner wall, allowing the accurate measurement of the luminal area to ±3.0{\%}. Conclusions. The pressure gradient can be estimated across stenoses noninvasively. The Young model was more accurate than the simplified Bernoulli equation in this model using steady flow. Estimated gradients are highly dependent on the definition of the vascular lumen, a process aided by the use of sonographic contrast.",
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