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American Institute of Ultrasound in Medicine <strong>Proceedings</strong> J Ultrasound Med 32(suppl):S1–S134, 2013lead to premature birth, yet there is no clinically established method to objectivelyand quantitatively measure softening. Our objective is to developa safe, reliable, noninvasive quantitative method to assess cervical softness.We have shown that shear wave speed estimation (SWS) is an effectivemethod to measure cervical softness in hysterectomy specimens. A criticalstep toward transitioning to in vivo studies is to determine the spatialvariability in cervical softness, and that is the aim of the current work.Methods—Five multiparous hysterectomy specimens fromnonpregnant women were bivalved, placed in a saline bath, and scannedwith a 9L4 linear array transducer aligned parallel with the endocervicalcanal using a Siemens Acuson S2000 system. SWS measurements wereobtained in 5 positions along the canal (10–30 mm from the external os)and at 3 depths from the surface of the canal (0.25–8.25 mm deep) with10 replicate measurements at each location. The shear wave speeds wereestimated using an iterative random sample consensus (RANSAC)method.Results—In all specimens, the shear wave speed systematicallyincreased along the canal from distal to proximal (closer to the uterus) onthe anterior side (1.47 ± 0.08 vs 4.54 ± 0.22 m/s for distal and proximal,respectively). This represents an increase in SWS of 1.5 m/s/cm along thelength of the cervix. The posterior side showed much greater, and less systematic,spatial variation (3.61 ± 0.98 vs 4.14 ± 0.58 m/s for distal andproximal, respectively). All estimates had a RANSAC inlier percentage of99%, representing strong confidence in the SWS estimates.Conclusions—Normal cervical tissue has a significant stiffnessgradient that can be characterized with acoustic radiation force-based shearelasticity imaging methods. With careful development and testing, SWSmeasurement will provide a means to noninvasively assess softening of thepregnant cervix and could be a useful research tool for exploring prematurecervical remodeling.New Investigator Award SessionModerators: Arthur Fleischer, MD, Elisa Konofagou, PhD1434714 Longitudinal Analysis of Grayscale Imaging and Electro -myography in an Animal Model of Carpal Tunnel SyndromeShawn Roll, 1 * Kevin Evans, 2 Kevin Volz, 2 Carolyn Sommerich 21Division of Occupational Science and Occupational Therapy,University of Southern California, Los Angeles, CaliforniaUSA; 2 School of Health and Rehabilitation Sciences, Ohio StateUniversity, Columbus, Ohio USAObjectives—The objective of this research was to determinethe ability of sonography to identify changes over time in median nervemorphology due to controlled exposure to a physical task related to the developmentof carpal tunnel syndrome.Methods—Fifteen Macaca fascicularis monkeys pinched alever while in various amounts of wrist flexion to receive a treat. Subjectsworked at a self-regulated pace up to 8 hours a day, 5 days a week, for 14weeks. Nerve conduction velocity (NCV) and sonographic evaluation ofthe median nerve were completed every other week during 4 weeks oftraining (baseline), 16 weeks of working, and 6 weeks of recovery. A GELOGIQ i with a 12-MHz linear transducer was used for sonographic evaluation.Cross-sectional area (CSA) was measured via a direct trace aroundthe inner hyperechoic border of the nerve in the forearm and at the levelof the pisiform. NCV and CSA measures were analyzed across the 3phases using analysis of variance and trend graphs.Results—NCV slowed slightly from baseline to the workingphase across all subjects (P = .03). CSA of the nerve at the level of thepisiform was noted to increase significantly from baseline and workingphases as compared to the recovery phase (P = .03). At the same time,CSA of the median nerve in the distal forearm did not change across thephases (P = .20).Conclusions—Based on this controlled study, changes in CSAof the median nerve can be observed over time and may be directly associatedwith work exposure. Sonography may be a highly useful tool forperiodic preventative screening for work-related musculoskeletal disorders.Early detection of these changes through longitudinal evaluations inworkers at risk for carpal tunnel syndrome could trigger interventionsmeant to reverse the progression of tissue pathology.Table 1. Average (SD) Nerve Measurements Across the Study PhasesBaseline Working Recovery PNerve conduction velocity, 35.96 (3.46) 34.33 (3.76) 34.81 (3.19) .03m/secCSA in forearm, mm 2 0.61 (0.15) 0.59 (0.16) 0.64 (0.17) .20CSA at pisiform, mm 2 0.82 (0.28) 0.81 (0.29) 0.96 (0.36) .03CSA change (pisiform – 0.20 (0.28) 0.22 (0.31) 0.30 (0.38) .27forearm), mm 21526604 Risk Reduction of Brain Infarction During CarotidEndarterectomy or Stenting Using Sonolysis: ProspectiveRandomized Study Pilot DataMartin Kuliha, 1 * David Školoudík, 1,4 Eva Hurtíková, 1Martin Roubec, 1 Andrea Goldírová, 1 Roman Herzig, 4 VáclavProcházka, 2 Tomáš Jonszta, 2 Dan Czerný, 2 Jan Krajča, 2 DavidOtáhal, 3 Tomáš Hrbáč 3 1 Neurology, 2 Radiology, 3 Neurosurgery,University Hospital Ostrava, Ostrava, Czech Republic;4 Neurology, University Hospital Olomouc, Olomouc, CzechRepublicObjectives—Sonolysis is a new therapeutic option for accelerationof arterial recanalization. The aim of this study was to confirm riskreduction of brain infarction during carotid endarterectomy (CEA) andcarotid stenting (CS) of the internal carotid artery (ICA) using sonolysiswith continuous transcranial Doppler monitoring by a diagnostic 2-MHzprobe.Methods—All patients with ICA stenosis >70%, an indicationfor CEA or CS, and signed informed consent were enrolled to the studyduring 18 months. Patients were randomized into 2 groups: group 1 withsonolysis during intervention and group 2 without sonolysis. Neurologicexamination, cognitive tests, and brain magnetic resonance imaging wereperformed before and 24 hours after intervention in all patients. New braininfarctions, infarctions >0.5 cm 3 , a mini–mental state examination, a clocktest, and a speech fluency test were statistically evaluated using a t test.Results—Totally, 127 patients were included in the study.Sixty-two (48 males; mean age, 65.6 ± 7.6 years) were randomized intogroup 1; 33 underwent CEA and 29 CS. Sixty-five patients (39 males;mean age, 65.6 ± 7.8 years) were randomized into group 2; 30 underwentCEA and 35 CS. New brain infarctions/infarctions >0.5 cm 3 were foundin 19 (30.6%)/4 (6.5%) patients in group 1 and in 26 (40.0%)/12 (18.5%)patients in group 2, respectively (P = .14/P = .02, respectively). No significantdifferences were found in cognitive tests (P > .05 in all tests).Conclusions—Sonolysis seems to be effective in prevention oflarge brain infarction during CEA and CS. (Supported by grants IGA MHCR NT/11386-5/2010, NT/11046-6/2010, and NT/13498-4/2012.)1536178 Measured Single-Bubble Postexcitation Collapse Thresholdsfor Standard and Size-Altered Ultrasound Contrast AgentsDaniel King, 1,2 * William O’Brien Jr 2,3 1 Mechanical Scienceand Engineering, 2 Bioacoustics Research Laboratory, 3 Electricaland Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois USAObjectives—Experimentally measured responses of ultrasoundcontrast agents (UCAs) at high acoustic pressures are valuable for imagingand therapeutic ultrasound applications as well as for interpreting bio-S49
American Institute of Ultrasound in Medicine <strong>Proceedings</strong> J Ultrasound Med 32(suppl):S1–S134, 2013effect mechanisms. Therefore, the goals for this research were to comparethe size distribution and shell composition dependence for a characteristictype of collapse using 2 commercially available UCAs, lipid-shelledDefinity and albumin-shelled Optison.Methods—Two Definity and 2 Optison populations of varyingsize distributions were tested. Experiments were conducted using a doublepassive cavitation detection setup at several frequencies (2.8–7.1 MHz)across a range of peak rarefactional pressures (0.1–6.0 MPa). Data wereanalyzed using a peak detection algorithm for the presence or absence ofthe postexcitation signal (PES), a rebound characteristic indicative of shellrupture, inertial cavitation, and symmetric collapse for single UCAs.Results—With standard preparations, Definity had lower postexcitationcollapse thresholds than Optison at most frequencies (Table 1).Using alternate preparations to change the mean size of the bubble populationshad little effect on these thresholds, except around 4.6 MHz.Furthermore, the predicted shift in PES thresholds using the Marmottantmodel followed similar trends to the experiments for Definity UCAs,showing greater variation around 4.6 MHz than at 2.8 or 7.1 MHz.Conclusions—Significant differences were found between thecollapse thresholds of Definity and Optison. Moreover, the comparisonsbetween varied size distributions showed that the different shell compositionshad a significant impact on the measured PES thresholds at allfrequencies, independent of mean size. (Supported by National Institutesof Health grant R37 EB002641.)Table 1. Mean Diameter ± SD and 50% Postexcitation Thresholds (95% ConfidenceIntervals) for Peak Rarefactional Pressure Amplitude50% 50% 50%UCA Mean Threshold at Threshold at Threshold atPopulation Diameter, µm 2.8 MHz, MPa 4.6 MHz, MPa 7.1 MHz, MPaDefinity 1.99 ± 0.54 0.81 (0.71–0.90) 2.26 (2.06–2.43) 3.90 (3.50–4.40)Altered Definity 2.50 ± 2.32 0.80 (0.75–0.85) 1.65 (1.56–1.72) 3.61 (3.30–4.19)Optison 4.24 ± 2.44 1.20 (0.99–1.39) 1.76 (1.34–2.06) 4.24 (2.81–4.94)Altered Optison 2.61 ± 2.04 1.17 (0.92–1.39) 2.62 (2.20–2.95) 4.04 (3.85–4.20)1538841 Computer-Assisted Detection of Proximal Arterial Stenosison Doppler UltrasoundJohn Millet, 1 * Gowthaman Gunabushanam, 1 Erik Stilp, 2Forrest Crawford, 3 Robert McNamara, 2 Leslie Scoutt 11Diagnostic Radiology, 2 Internal Medicine, Yale UniversitySchool of Medicine, New Haven, Connecticut USA; 3 Biostatistics,Yale University School of Public Health, New Haven,Connecticut USAObjectives—To determine if use of a novel computer-generatedquantitative measure, effective acceleration time (effAT), can improveaccuracy for detecting proximal arterial stenosis on Dopplerultrasound.Methods—This was a retrospective case-control study wherebyaortic stenosis (AS) was used as a model to detect distal tardus parvusphysiology. Patients with echocardiography-confirmed AS (n = 132; 60mild, 44 moderate, 28 severe) and controls (n = 48) who underwent carotidultrasound within 90 days were identified through a diagnostic imagingdatabase at a single medical center. A custom-built computerized spectralanalysis program generated effAT values for all carotid artery spectralDoppler waveforms, and a receiver operating characteristic (ROC) analysiswas performed to determine the optimal median effAT cutoff value todetect AS. Two radiologists, blinded to subject disease status, reviewedall carotid sonograms for the presence of tardus parvus waveforms. Interobservervariability was measured, and the accuracy of the radiologists todetect AS with and without use of the effAT cutoff was calculated. Accuracyof the effAT cutoff to detect AS independent of radiologist waveforminterpretation was also determined.Results—There were no significant differences between casesand controls with regard to age, sex, body mass index, or ejection fraction.Accuracy of radiologist detection of AS via waveform interpretationranged from 43% to 61%. Observer agreement in the detection of tardusparvus waveforms was 76% (136/180 cases; Κ = 0.44; P < .001). ROCanalysis revealed an optimal effAT cutoff of ≥48 milliseconds to detectAS with a corresponding area under the curve of 0.77 (95% confidence interval,0.74–0.84). Use of the effAT cutoff independent of radiologistwaveform interpretation demonstrated accuracy of 72%. The combinationof a tardus parvus pattern and a median effAT of ≥48 millisecondsdemonstrated an accuracy range of 73% to 74%.Conclusions—Radiologist detection of proximal arterial stenosisthough visual interpretation of spectral Doppler waveform morphologyis limited by low accuracy and moderate interobserver variability. Use ofa computer-generated median effAT cutoff markedly improves diagnosticaccuracy and eliminates observer variability.1536020 Contrast Ultrasound Imaging of the Aorta Does Not AffectProgression of Atherosclerosis in ApoE–/– MiceBrendon Smith, 1,2 * Douglas Simpson, 3 Sandhya Sarwate, 1,4Rita Miller, 1 Rami Abuhabsah, 1 John Erdman, 2,5 WilliamO’Brien Jr 1,2 1 Bioacoustics Research Laboratory, Electricaland Computer Engineering, 2 Division of Nutritional Sciences,3Statistics, 4 Pathology, 5 Food Science and Human Nutrition,University of Illinois at Urbana-Champaign, Urbana, IllinoisUSAObjectives—Ultrasound contrast agents (UCAs) are used clinicallyto enhance ultrasound imaging of the cardiovascular system. Adversebiological effects have been noted after administration of UCAs inhuman patients and animal models, and more research is needed for acomprehensive understanding of the biological effects of UCAs. We usedthe ApoE –/– mouse model of atherosclerosis to characterize these effects.Methods—Male ApoE –/– mice (8 weeks old; n = 38) were intravenouslyinfused with the Definity UCA (2 × 10 10 UCA/h) and eitherexposed to 2.8-MHz, 10-Hz pulse repetition frequency, 1.4-microsecondpulse duration, 2-minute exposure duration, 1.4-MPa peak rarefactionalpressure amplitude ultrasound or sham exposed, and then consumed eithera chow or Western diet for either 4 or 8 weeks after ultrasound exposure(n = 4–5 per group). The ultrasound exposure conditions, by design andindependent measures, matched Definity’s 80% collapse threshold. Bloodplasma samples were collected before ultrasound exposure and at 2, 4, 6,and 8 weeks after exposure. Animals were then euthanized, and tissueswere collected for analysis. A pathologist measured atheroma thicknessin formalin-fixed, hematoxylin-eosin–stained transverse sections of theaorta and scored them for severity of atherosclerosis.Results—Plasma total cholesterol initially averaged 302 mg/dLin the Western diet group, increased significantly to 742 mg/dL after 2weeks on the diet (P < .0001), and remained significantly elevated afterthat. Total cholesterol increased significantly from 309 mg/dL at baselineto 420 mg/dL in the chow diet group after 4 weeks (P < .05) but was notsignificantly different from baseline at 6 or 8 weeks. Total cholesterol wassignificantly greater in the Western diet group than the chow group for alltime points after baseline (P < .0001). Atheroma thickness was significantlygreater in animals consuming the Western diet than in chow-fedanimals (P < .001) and in animals euthanized after 8 weeks than after 4weeks (P < .005). Ultrasound did not affect plasma total cholesterol levelsor atheroma thickness.Conclusions—Contrast ultrasound did not increase the severityof atherosclerosis in the ApoE –/– mouse model. (Supported by NationalInstitutes of Health grant R37EB002641.)S50
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2013Journal ofUltrasoundin Medicine
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Small-Animal Preclinical High-Frequ
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2013 AIUM Award WinnersJoseph H. Ho
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2013 AIUM Award WinnersDistinguishe
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Endowment for Education andResearch
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Rosa De Vermette, MD, RDCS,RDMS, RO
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Kee-Hak Lim, MDG. Sharat Lin, PhDTo
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