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Ultrasonic tissue characterization: Applicability and sensitivity of detection of serial changes in the myocardium
380
Abstracts
102N
ULTRASONIC TISSUE C H A R A C T E R I Z A T I O N : A P P L I C A B I L I T Y AND SENSITIVITY OF D E T E C T I O N OF SERIAL CHANGES IN T H E M Y O C A R D I U M Sameh K, Mobarek MD, David R. Richards DO, Percy J. Colon III MD, Mario F. Meza MD, Carlos A. Moreno, Susan E. Revall, Joseph P. Murgo MD, Jorge Cheirif MD. Ochsner Medical Institutions, New Orleans, LA Tissue characterization (TC) has been used to differentiate normal from abnormal myocardium. Thus far, the equipment used has consisted of prototype equipment limiting its use to selected investigators. To determine if TC (using commercialy produced equipment) could distinguish ischemic from irreversibly injured myocardium, we studied 14 open-chest mongrel dogs in which 4-6 hours of coronary occlusion followed by 3 hours of reperfusion (REP) were done. TC was performed in the short axis view during baseline (B1), coronary (LAD or LCX) occlusion (OC), early and late reperfusion, and following IV dipyridamole administration (3 hours post-reperfusion). Off-line analysis was then done using a commercially produced Acoustic Densitometry (AD) package (Hewlett-Packard Sonos 1500). The peak to peak (PP) difference in integrated backscatter (in dB) throughout the cardiac cycle was used as the parameter of TC. The PP ratio of ischemic to control region was analyzed (ANOVA) during the various interventions described above. Results: Five of the dogs developed infarcts (MI) by TTC staining whereas 9 did not. Early Late Dipyridamole B1 0(2 REP REP -REP MI 1.0+.13 .32+.11 .32-+.11 .40+.05 .38+.20 * No MI 0.9+_.07 .38+.05 .59+.06 .70+.18 .72+.20 #t *p<0.001 difference of all events from respective baseline #p<0.003 difference of all events from respective baseline ~'p<0.01 compared to MI (Dipyridamole-REP) We conclude that TC with the AD package can be used to distinguish ischerdic from non-ischemic and from necrotic myocardium.
1020
Carotid Artery Plaque Tissue Characterization Using Radiofrequency Backscatter Analysis Sandra C. Carr, Michael J. Vonesh, David D. McPherson, James S.T. Yao, Northwestern University Medical School,Chicago, Illinois
Tissue characteristics of carotid artery plaques have been correlated with the propensity of a stenotic lesion to produce ischemic cerebrovascular symptoms. To determine if radiofrequency (RF) ultrasound can be used to characterize atherosclerotic plaque components, 14 carotid endarteroctomy specimens were analyzed immediately following removal using RF signal analysis with a 7MHz ultrasound probe. Computer-analyzed regions of interest were identically marked for histopathological analysis. Results: Calcium content and the presence of a necrotic core were positively related to the RF integrated backscatter coherent energy (IBE). These variables accounted for 61% of the total variation in integrated backscatter coherent energy (r=0.78). Other factors, including plaque hemorrhage, thrombus intraplaque fibrin, and plaque type, did not correlate with IBE. Conclusion: RF backscatter analysis can be used to determine important pathologic components of carotid plaques. This new RF ultrasonic technique, which can be used at time of vascular ultrasound, may be a valuable tool to predict pathologic consequences of the underlying plaque.
Journal of the American Society o£ Echocardiograpby May-June 1996
Abstract Poster Session 201 Contrast Echocardiography 201A
LOCALIZED DELIVERY OF OLIGONUCLEOT1DES TO TARGET ORGANS WITH EXTERNAL DIAGNOSTIC ULTRASOUND AND INTRAVENOUS PERFLUOROCARBON-EXPOSED SONICATED DEXTROSE ALBUMIN ULTRASOUND CONTRAST. Thomas Porter, M.D., Patrick Iversen, Ph.D., Feng Xie, M.D.; University of Nebraska Medical Center, Omaha, Nebraska. Diagnostic ultrasound (DU) pressures may be capable of inducing cavitation ~f intravenously injected microbubbles when they reach the insonified organ. I'his cavitation results in marked oscillations in microbubble size, and even destruction We have recently discovered tbat the albumin in perfluoroearbon-exposed sonieated dextrose albumin (PESDA) m icrobubble ultrasound contrast retains its affinity for binding substances, including antisense oligonueleotides (OG) used to inhibit intimal prolifcratiou. Since DU pressures destroy these bubbles, we hypothesized that DU would be capable of locally releasing OG from intravenously injected OG-labelled PESDA mierobubbles by this cavitation process. Accordingly, we first tested the ability of DU to release OG-bound PESDA by injecting these microbubbles into a flow cell which was either insonified (1.1 Megapaseals peak negative pressure, 2.0 Megahertz frequency) with DU (exposed OGPESDA) or not insonified (unexposed OG-PESDA). Effluent samples from both exposed and unexposed OG-PESDA were then allowed to stand to separate into upper bubble and lower non-bubble containing layers, and %OG in each layer was measured. Next, OG-PESDA (0.2-0.4 ml) was given intravenously in two healthy dogs, and uptake of OG (using a gene soanner and histology) in the kidney were measured post-mortem; one kidney was being insonified following injection; the opposite kidney was not insonified. OG separated into both the bubble and non-bubble containing layers of the effluent after exposure to DU in vitro, while OG stayed mainly in the bubble layer of unexposed OG-PESDA, suggesting OG release occurred in the presence of DU. Gone scanning demonstrated a significantly bigher uptake of intact OG in the DU-exposed kidney. Histology and fluorescence of each kidney confirmed that the DU-exposed kidney had significantly higher OG content, with the majority of OG uptake occurring in glomm~lar cells and proximal collecting tubules. These data indicate that PESDA ultrasound contrast may serve as a carrier for intravenously-injected OG, and be used with external DU to target their delivery to specific organ sites.
201B O P T I M A L C A R D I A C C Y C L E T R I G G E R I N G F R E Q U E N C Y D U R I N G F U N D A M E N T A L AND SECOND HARMONIC IMAGING Percy J. Colon III MD, David R. Richards DO, Carlos A. Moreno, Susan E. Revall, Joseph P. Murgo MD, Patrick G. Rafter, Jorge CbeirifMD. Ochsner Medic~fl Institutions, NewOrleans, LA Intermittent cardiac cycle imaging has been reported to improve the visual appreciation of myocardial perfusion. To determine the optimal cardiac cycle triggering (CCT) frequency during fundamental (Fund) (2.5 MHz) and second harmonic imaging (Harm) (2.5/5.0 MHz), baseline images in 13 open-chest dogs were performed during the 1V injection of 0.1 cc of FSO69. The frequency of image acquisition was performed during end diastole of each cardiac cycle as well as every third and fifth cardiac cycle. MyocardM perfusion was objectively determined by measuring on-line videodensitometry of peak intensity (PI) using a Hewlett-Packard SONOS 2500 and subjectively graded using a clinically relevant visual scoring (VS) system (0: unacceptable, 1: fair LV cavity opacification (LVO) but insignificant myocardial opacification (MO), 2: excellent LVO but insignificant MO, 3: excellent LVO and fair MO, 4: excellent LVO and MO, and 0.5 deducted for attenuation). Results: Peak Intensity Visual Score CCT Fund Harm Fund Harm each beat 0.6+-0.4 i 1 . 7 + 1 . 3 2.4±0.5 i 3.0+0.4 3rdbeat 1.2-+0.6 i 4.0_+3.9 2.9±0.5 i 3.6+0.5 5th beat 1.2 -+ 0.5 i 4.3 _+ 3.6 3.3 -+ 0.5 i 3.9 -+ 0.2 Significant differences were observed for both PI and VS (p<0.01) between imaging during each beat and 3rd or 5th beat, but not between the 3rd and 5th beat. Conclusion: Cardiac cycle triggering on every third or fifth beat enhances myocardiN perfusion detection compared to imaging of each cardiac cycle. This benefit was seen during imaging in both fundamental and second harmonic modes.
Abstracts
102N
ULTRASONIC TISSUE C H A R A C T E R I Z A T I O N : A P P L I C A B I L I T Y AND SENSITIVITY OF D E T E C T I O N OF SERIAL CHANGES IN T H E M Y O C A R D I U M Sameh K, Mobarek MD, David R. Richards DO, Percy J. Colon III MD, Mario F. Meza MD, Carlos A. Moreno, Susan E. Revall, Joseph P. Murgo MD, Jorge Cheirif MD. Ochsner Medical Institutions, New Orleans, LA Tissue characterization (TC) has been used to differentiate normal from abnormal myocardium. Thus far, the equipment used has consisted of prototype equipment limiting its use to selected investigators. To determine if TC (using commercialy produced equipment) could distinguish ischemic from irreversibly injured myocardium, we studied 14 open-chest mongrel dogs in which 4-6 hours of coronary occlusion followed by 3 hours of reperfusion (REP) were done. TC was performed in the short axis view during baseline (B1), coronary (LAD or LCX) occlusion (OC), early and late reperfusion, and following IV dipyridamole administration (3 hours post-reperfusion). Off-line analysis was then done using a commercially produced Acoustic Densitometry (AD) package (Hewlett-Packard Sonos 1500). The peak to peak (PP) difference in integrated backscatter (in dB) throughout the cardiac cycle was used as the parameter of TC. The PP ratio of ischemic to control region was analyzed (ANOVA) during the various interventions described above. Results: Five of the dogs developed infarcts (MI) by TTC staining whereas 9 did not. Early Late Dipyridamole B1 0(2 REP REP -REP MI 1.0+.13 .32+.11 .32-+.11 .40+.05 .38+.20 * No MI 0.9+_.07 .38+.05 .59+.06 .70+.18 .72+.20 #t *p<0.001 difference of all events from respective baseline #p<0.003 difference of all events from respective baseline ~'p<0.01 compared to MI (Dipyridamole-REP) We conclude that TC with the AD package can be used to distinguish ischerdic from non-ischemic and from necrotic myocardium.
1020
Carotid Artery Plaque Tissue Characterization Using Radiofrequency Backscatter Analysis Sandra C. Carr, Michael J. Vonesh, David D. McPherson, James S.T. Yao, Northwestern University Medical School,Chicago, Illinois
Tissue characteristics of carotid artery plaques have been correlated with the propensity of a stenotic lesion to produce ischemic cerebrovascular symptoms. To determine if radiofrequency (RF) ultrasound can be used to characterize atherosclerotic plaque components, 14 carotid endarteroctomy specimens were analyzed immediately following removal using RF signal analysis with a 7MHz ultrasound probe. Computer-analyzed regions of interest were identically marked for histopathological analysis. Results: Calcium content and the presence of a necrotic core were positively related to the RF integrated backscatter coherent energy (IBE). These variables accounted for 61% of the total variation in integrated backscatter coherent energy (r=0.78). Other factors, including plaque hemorrhage, thrombus intraplaque fibrin, and plaque type, did not correlate with IBE. Conclusion: RF backscatter analysis can be used to determine important pathologic components of carotid plaques. This new RF ultrasonic technique, which can be used at time of vascular ultrasound, may be a valuable tool to predict pathologic consequences of the underlying plaque.
Journal of the American Society o£ Echocardiograpby May-June 1996
Abstract Poster Session 201 Contrast Echocardiography 201A
LOCALIZED DELIVERY OF OLIGONUCLEOT1DES TO TARGET ORGANS WITH EXTERNAL DIAGNOSTIC ULTRASOUND AND INTRAVENOUS PERFLUOROCARBON-EXPOSED SONICATED DEXTROSE ALBUMIN ULTRASOUND CONTRAST. Thomas Porter, M.D., Patrick Iversen, Ph.D., Feng Xie, M.D.; University of Nebraska Medical Center, Omaha, Nebraska. Diagnostic ultrasound (DU) pressures may be capable of inducing cavitation ~f intravenously injected microbubbles when they reach the insonified organ. I'his cavitation results in marked oscillations in microbubble size, and even destruction We have recently discovered tbat the albumin in perfluoroearbon-exposed sonieated dextrose albumin (PESDA) m icrobubble ultrasound contrast retains its affinity for binding substances, including antisense oligonueleotides (OG) used to inhibit intimal prolifcratiou. Since DU pressures destroy these bubbles, we hypothesized that DU would be capable of locally releasing OG from intravenously injected OG-labelled PESDA mierobubbles by this cavitation process. Accordingly, we first tested the ability of DU to release OG-bound PESDA by injecting these microbubbles into a flow cell which was either insonified (1.1 Megapaseals peak negative pressure, 2.0 Megahertz frequency) with DU (exposed OGPESDA) or not insonified (unexposed OG-PESDA). Effluent samples from both exposed and unexposed OG-PESDA were then allowed to stand to separate into upper bubble and lower non-bubble containing layers, and %OG in each layer was measured. Next, OG-PESDA (0.2-0.4 ml) was given intravenously in two healthy dogs, and uptake of OG (using a gene soanner and histology) in the kidney were measured post-mortem; one kidney was being insonified following injection; the opposite kidney was not insonified. OG separated into both the bubble and non-bubble containing layers of the effluent after exposure to DU in vitro, while OG stayed mainly in the bubble layer of unexposed OG-PESDA, suggesting OG release occurred in the presence of DU. Gone scanning demonstrated a significantly bigher uptake of intact OG in the DU-exposed kidney. Histology and fluorescence of each kidney confirmed that the DU-exposed kidney had significantly higher OG content, with the majority of OG uptake occurring in glomm~lar cells and proximal collecting tubules. These data indicate that PESDA ultrasound contrast may serve as a carrier for intravenously-injected OG, and be used with external DU to target their delivery to specific organ sites.
201B O P T I M A L C A R D I A C C Y C L E T R I G G E R I N G F R E Q U E N C Y D U R I N G F U N D A M E N T A L AND SECOND HARMONIC IMAGING Percy J. Colon III MD, David R. Richards DO, Carlos A. Moreno, Susan E. Revall, Joseph P. Murgo MD, Patrick G. Rafter, Jorge CbeirifMD. Ochsner Medic~fl Institutions, NewOrleans, LA Intermittent cardiac cycle imaging has been reported to improve the visual appreciation of myocardial perfusion. To determine the optimal cardiac cycle triggering (CCT) frequency during fundamental (Fund) (2.5 MHz) and second harmonic imaging (Harm) (2.5/5.0 MHz), baseline images in 13 open-chest dogs were performed during the 1V injection of 0.1 cc of FSO69. The frequency of image acquisition was performed during end diastole of each cardiac cycle as well as every third and fifth cardiac cycle. MyocardM perfusion was objectively determined by measuring on-line videodensitometry of peak intensity (PI) using a Hewlett-Packard SONOS 2500 and subjectively graded using a clinically relevant visual scoring (VS) system (0: unacceptable, 1: fair LV cavity opacification (LVO) but insignificant myocardial opacification (MO), 2: excellent LVO but insignificant MO, 3: excellent LVO and fair MO, 4: excellent LVO and MO, and 0.5 deducted for attenuation). Results: Peak Intensity Visual Score CCT Fund Harm Fund Harm each beat 0.6+-0.4 i 1 . 7 + 1 . 3 2.4±0.5 i 3.0+0.4 3rdbeat 1.2-+0.6 i 4.0_+3.9 2.9±0.5 i 3.6+0.5 5th beat 1.2 -+ 0.5 i 4.3 _+ 3.6 3.3 -+ 0.5 i 3.9 -+ 0.2 Significant differences were observed for both PI and VS (p<0.01) between imaging during each beat and 3rd or 5th beat, but not between the 3rd and 5th beat. Conclusion: Cardiac cycle triggering on every third or fifth beat enhances myocardiN perfusion detection compared to imaging of each cardiac cycle. This benefit was seen during imaging in both fundamental and second harmonic modes.