Sonicated X-ray contrast agents for quantitative myocardial contrast echocardiography - a critical approach

I. V. Mayer, M. P. Lazarov, Urs Utzinger, A. U. Freiburghaus, O. M. Hess

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Contrast echocardiography with sonicated radiographic contrast agents has been used for the qualitative and quantitative determination of myocardial blood flow. One major problem has been the size of the microbubbles since only bubbles smaller than 8 μm are expected to pass the capillary bed and larger bubbles may obstruct the capillaries and, thus, alter myocardial blood flow. These techniques have been used for several years, but their reliability has not yet been assessed accurately. Five different methods for the production of sonicated radiographic contrast agents (methods 1-3 from the literature, and 4 and 5 from our laboratory; M1-5) were evaluated for their use in quantitative contrast echocardiography. The sonication of non-ionic X-ray contrast media was performed with a standard titanium probe (20 kHz) for methods 1-4, with variation in the sonication time and the number of sonication jets used for each method. In M5, we used bubbles that were produced by the insufflation of oxygen in the X-ray contrast agent; large (>8 μm) bubbles were destroyed by sonication at 380kHz (resonance method). Mean bubble size was determined by computerized videomicroscopy. The effect of bubble size on the backscatter of the ultrasonic signal was calculated for each method. Mean bubble size (±1 SD) ranged between 11.5 ± 4μm and 16.1 ± 14 μm for M1-M5. The best values, i.e., the smallest bubbles, were found with M4 (prepressurized contrast medium). Assuming capillary passage for bubbles smaller than 8 μm, only 14%-48% of the bubbles were smaller than 8 μm (M1-M5). The best results with regard to bubble size (≤8 μm) were observed with M5 (48% ≤8 μm). In regard to the influence of bubble size on the backscatter of the ultrasonic signal, 56%-98.5% of the signal was produced by bubbles larger than 15 μm (M1-5) but the best results were obtained with M4. It is concluded that capillary-passage of sonicated microbubbles (≤8 μm) can be expected in only 14%-48% of the bubbles for the five different sonication techniques. More than 50% of all microbubbles produced by these techniques are larger than the expected 8 μm. These large bubbles are responsible for the backscatter of the ultrasonic signal in the vast majority of cases. Thus, the sonication of radiographic contrast agents appears to be inappropriate for the production of uniformly small microbubbles and, thus, this method is not suitable for quantitative measurements of coronary blood flow.

Original languageEnglish (US)
Pages (from-to)96-105
Number of pages10
JournalHeart and Vessels
Volume10
Issue number2
DOIs
StatePublished - Apr 1995
Externally publishedYes

Fingerprint

Sonication
Contrast Media
Echocardiography
Microbubbles
X-Rays
Ultrasonics
Video Microscopy
Insufflation
Titanium
Oxygen

Keywords

  • Backscatter intensity
  • Microbubbles
  • Non-ionic radiographic contrast agent
  • Quantitative myocardial blood flow
  • Sonication

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Sonicated X-ray contrast agents for quantitative myocardial contrast echocardiography - a critical approach. / Mayer, I. V.; Lazarov, M. P.; Utzinger, Urs; Freiburghaus, A. U.; Hess, O. M.

In: Heart and Vessels, Vol. 10, No. 2, 04.1995, p. 96-105.

Research output: Contribution to journalArticle

Mayer, I. V. ; Lazarov, M. P. ; Utzinger, Urs ; Freiburghaus, A. U. ; Hess, O. M. / Sonicated X-ray contrast agents for quantitative myocardial contrast echocardiography - a critical approach. In: Heart and Vessels. 1995 ; Vol. 10, No. 2. pp. 96-105.
@article{dc3344430522494eb42a1640df0f9f0e,
title = "Sonicated X-ray contrast agents for quantitative myocardial contrast echocardiography - a critical approach",
abstract = "Contrast echocardiography with sonicated radiographic contrast agents has been used for the qualitative and quantitative determination of myocardial blood flow. One major problem has been the size of the microbubbles since only bubbles smaller than 8 μm are expected to pass the capillary bed and larger bubbles may obstruct the capillaries and, thus, alter myocardial blood flow. These techniques have been used for several years, but their reliability has not yet been assessed accurately. Five different methods for the production of sonicated radiographic contrast agents (methods 1-3 from the literature, and 4 and 5 from our laboratory; M1-5) were evaluated for their use in quantitative contrast echocardiography. The sonication of non-ionic X-ray contrast media was performed with a standard titanium probe (20 kHz) for methods 1-4, with variation in the sonication time and the number of sonication jets used for each method. In M5, we used bubbles that were produced by the insufflation of oxygen in the X-ray contrast agent; large (>8 μm) bubbles were destroyed by sonication at 380kHz (resonance method). Mean bubble size was determined by computerized videomicroscopy. The effect of bubble size on the backscatter of the ultrasonic signal was calculated for each method. Mean bubble size (±1 SD) ranged between 11.5 ± 4μm and 16.1 ± 14 μm for M1-M5. The best values, i.e., the smallest bubbles, were found with M4 (prepressurized contrast medium). Assuming capillary passage for bubbles smaller than 8 μm, only 14{\%}-48{\%} of the bubbles were smaller than 8 μm (M1-M5). The best results with regard to bubble size (≤8 μm) were observed with M5 (48{\%} ≤8 μm). In regard to the influence of bubble size on the backscatter of the ultrasonic signal, 56{\%}-98.5{\%} of the signal was produced by bubbles larger than 15 μm (M1-5) but the best results were obtained with M4. It is concluded that capillary-passage of sonicated microbubbles (≤8 μm) can be expected in only 14{\%}-48{\%} of the bubbles for the five different sonication techniques. More than 50{\%} of all microbubbles produced by these techniques are larger than the expected 8 μm. These large bubbles are responsible for the backscatter of the ultrasonic signal in the vast majority of cases. Thus, the sonication of radiographic contrast agents appears to be inappropriate for the production of uniformly small microbubbles and, thus, this method is not suitable for quantitative measurements of coronary blood flow.",
keywords = "Backscatter intensity, Microbubbles, Non-ionic radiographic contrast agent, Quantitative myocardial blood flow, Sonication",
author = "Mayer, {I. V.} and Lazarov, {M. P.} and Urs Utzinger and Freiburghaus, {A. U.} and Hess, {O. M.}",
year = "1995",
month = "4",
doi = "10.1007/BF01744500",
language = "English (US)",
volume = "10",
pages = "96--105",
journal = "Heart and Vessels",
issn = "0910-8327",
publisher = "Springer Japan",
number = "2",

}

TY - JOUR

T1 - Sonicated X-ray contrast agents for quantitative myocardial contrast echocardiography - a critical approach

AU - Mayer, I. V.

AU - Lazarov, M. P.

AU - Utzinger, Urs

AU - Freiburghaus, A. U.

AU - Hess, O. M.

PY - 1995/4

Y1 - 1995/4

N2 - Contrast echocardiography with sonicated radiographic contrast agents has been used for the qualitative and quantitative determination of myocardial blood flow. One major problem has been the size of the microbubbles since only bubbles smaller than 8 μm are expected to pass the capillary bed and larger bubbles may obstruct the capillaries and, thus, alter myocardial blood flow. These techniques have been used for several years, but their reliability has not yet been assessed accurately. Five different methods for the production of sonicated radiographic contrast agents (methods 1-3 from the literature, and 4 and 5 from our laboratory; M1-5) were evaluated for their use in quantitative contrast echocardiography. The sonication of non-ionic X-ray contrast media was performed with a standard titanium probe (20 kHz) for methods 1-4, with variation in the sonication time and the number of sonication jets used for each method. In M5, we used bubbles that were produced by the insufflation of oxygen in the X-ray contrast agent; large (>8 μm) bubbles were destroyed by sonication at 380kHz (resonance method). Mean bubble size was determined by computerized videomicroscopy. The effect of bubble size on the backscatter of the ultrasonic signal was calculated for each method. Mean bubble size (±1 SD) ranged between 11.5 ± 4μm and 16.1 ± 14 μm for M1-M5. The best values, i.e., the smallest bubbles, were found with M4 (prepressurized contrast medium). Assuming capillary passage for bubbles smaller than 8 μm, only 14%-48% of the bubbles were smaller than 8 μm (M1-M5). The best results with regard to bubble size (≤8 μm) were observed with M5 (48% ≤8 μm). In regard to the influence of bubble size on the backscatter of the ultrasonic signal, 56%-98.5% of the signal was produced by bubbles larger than 15 μm (M1-5) but the best results were obtained with M4. It is concluded that capillary-passage of sonicated microbubbles (≤8 μm) can be expected in only 14%-48% of the bubbles for the five different sonication techniques. More than 50% of all microbubbles produced by these techniques are larger than the expected 8 μm. These large bubbles are responsible for the backscatter of the ultrasonic signal in the vast majority of cases. Thus, the sonication of radiographic contrast agents appears to be inappropriate for the production of uniformly small microbubbles and, thus, this method is not suitable for quantitative measurements of coronary blood flow.

AB - Contrast echocardiography with sonicated radiographic contrast agents has been used for the qualitative and quantitative determination of myocardial blood flow. One major problem has been the size of the microbubbles since only bubbles smaller than 8 μm are expected to pass the capillary bed and larger bubbles may obstruct the capillaries and, thus, alter myocardial blood flow. These techniques have been used for several years, but their reliability has not yet been assessed accurately. Five different methods for the production of sonicated radiographic contrast agents (methods 1-3 from the literature, and 4 and 5 from our laboratory; M1-5) were evaluated for their use in quantitative contrast echocardiography. The sonication of non-ionic X-ray contrast media was performed with a standard titanium probe (20 kHz) for methods 1-4, with variation in the sonication time and the number of sonication jets used for each method. In M5, we used bubbles that were produced by the insufflation of oxygen in the X-ray contrast agent; large (>8 μm) bubbles were destroyed by sonication at 380kHz (resonance method). Mean bubble size was determined by computerized videomicroscopy. The effect of bubble size on the backscatter of the ultrasonic signal was calculated for each method. Mean bubble size (±1 SD) ranged between 11.5 ± 4μm and 16.1 ± 14 μm for M1-M5. The best values, i.e., the smallest bubbles, were found with M4 (prepressurized contrast medium). Assuming capillary passage for bubbles smaller than 8 μm, only 14%-48% of the bubbles were smaller than 8 μm (M1-M5). The best results with regard to bubble size (≤8 μm) were observed with M5 (48% ≤8 μm). In regard to the influence of bubble size on the backscatter of the ultrasonic signal, 56%-98.5% of the signal was produced by bubbles larger than 15 μm (M1-5) but the best results were obtained with M4. It is concluded that capillary-passage of sonicated microbubbles (≤8 μm) can be expected in only 14%-48% of the bubbles for the five different sonication techniques. More than 50% of all microbubbles produced by these techniques are larger than the expected 8 μm. These large bubbles are responsible for the backscatter of the ultrasonic signal in the vast majority of cases. Thus, the sonication of radiographic contrast agents appears to be inappropriate for the production of uniformly small microbubbles and, thus, this method is not suitable for quantitative measurements of coronary blood flow.

KW - Backscatter intensity

KW - Microbubbles

KW - Non-ionic radiographic contrast agent

KW - Quantitative myocardial blood flow

KW - Sonication

UR - http://www.scopus.com/inward/record.url?scp=0028933994&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028933994&partnerID=8YFLogxK

U2 - 10.1007/BF01744500

DO - 10.1007/BF01744500

M3 - Article

VL - 10

SP - 96

EP - 105

JO - Heart and Vessels

JF - Heart and Vessels

SN - 0910-8327

IS - 2

ER -