### 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 language | English (US) |
---|---|

Pages (from-to) | 683-691 |

Number of pages | 9 |

Journal | Journal of Ultrasound in Medicine |

Volume | 23 |

Issue number | 5 |

State | Published - Jan 1 2004 |

### Fingerprint

### 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

*Journal of Ultrasound in Medicine*,

*23*(5), 683-691.

**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.

Research output: Contribution to journal › Article

*Journal of Ultrasound in Medicine*, vol. 23, no. 5, pp. 683-691.

}

TY - JOUR

T1 - Noninvasive Estimation of the Pressure Gradient Across Stenoses Using Sonographic Contrast

T2 - In Vitro Validation

AU - Lien, Winston W.

AU - Lee, Allen H.

AU - Kono, Yuko

AU - Steinbach, Greg C.

AU - Mattrey, Robert F.

PY - 2004/1/1

Y1 - 2004/1/1

N2 - 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.

AB - 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.

KW - Arterial stenosis

KW - Bernoulli equation

KW - Flow velocity

KW - Model

KW - Pressure gradient

KW - Young method

UR - http://www.scopus.com/inward/record.url?scp=2342465565&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=2342465565&partnerID=8YFLogxK

M3 - Article

VL - 23

SP - 683

EP - 691

JO - Journal of Ultrasound in Medicine

JF - Journal of Ultrasound in Medicine

SN - 0278-4297

IS - 5

ER -