Official Proceedings - AIUM

More documents

Recommendations

Info

American Institute of Ultrasound in Medicine <strong>Proceedings</strong> J Ultrasound Med 32(suppl):S1–S134, 2013pass filter (HPF) with an adjustable cutoff frequency, and differentiationof the displacement vs time data. The latter determines the axial velocityof the propagating pulse and allows the wave arrival time to be determinedfrom the peak slope of the leading edge. This differentiation acts as a rampfilter in the frequency domain to reduce the effects of low-frequency motion.After filtering, SWSs were estimated using the arrival time as a functionof position data and the radon sum algorithm.Results—Results obtained to date indicate that the applicationof motion filters does affect the reconstructed SWS. Both the HPF anddifferentiation filter bias the estimated group velocity to the higher phasevelocity components; this effect is less significant for the quadratic filter.The differentiation filter leads to an ≈16% increase in SWS estimates overthe range of 1.5 to 4.0 m/s compared to the quadratic filter. For the HPF,increasing the cutoff frequency from 25 to 150 Hz increases the SWS≈13% over the same SWS range.Conclusions—Preprocessing algorithms used to remove lowfrequencynoise and motion artifacts from in vivo data can skew groupvelocity SWS estimates toward the higher phase velocity components.1540991 Evaluation of Shear Wave Elasticity Imaging for Characterizingthe Contribution of Coronary Perfusion to CardiacDiastolic StiffnessMaryam Vejdani-Jahromi,* Annette Kiplagat, YoungJoong-Kim, Douglas Dumont, Gregg Trahey, Patrick WolfBiomedical Engineering, Duke University, Durham, NorthCarolina USAObjectives—Heart failure is one of the leading causes of deathin the world in which mechanical properties of the cardiac tissue are damaged.Diastolic heart failure occurs when the left ventricle loses its complianceto receive a sufficient volume of blood. Currently, there is nouniversally accepted technique to evaluate changes in mechanical propertiesof cardiac tissue. Shear wave elasticity imaging (SWEI) is an ultrasound-basedtechnique used to evaluate the stiffness of the tissue bymeasuring the shear wave speed of propagation. To evaluate the capabilityof SWEI in determining the contribution of coronary perfusion to diastolicstiffness, normal and hypoperfused rabbit hearts were studied.Methods—Six rabbit hearts were isolated on a Langendorffpreparation, perfused with Tyrode solution. Data were acquired using aVF10-5 linear transducer on a Sonoline Antares ultrasound system (SiemensMedical Solutions, Mountain View, CA) with a focal point of 1.6 cm, transmitfrequency of 5.7 MHz and F-number of 1.5. The probe was fixed approximately1 cm from the left ventricular free wall along the short axis andacquired data from the same location. Hypoperfusion was done in 3 isolatedhearts by reducing the perfusion pressure until the flow rate was half of normal,and SWEI data were recorded before and 10 minutes after. Three rabbithearts with a normal flow rate were studied as control subjects.Results—Initial results showed that reduction of 50% in perfusionpressure caused an average decrease of 27.7% in the shear wave velocityand 47.7% in the shear modulus, while normal hearts showedincreases of 9.0% and 18.7% for the shear wave velocity and shear modulus,respectively.Conclusions—From these preliminary data, we conclude thatthe shear wave velocity and shear modulus recorded by SWEI can showthe contribution of coronary perfusion pressure to diastolic stiffness. Thisnew ultrasound-based imaging modality can be used to assess, characterize,and quantify the mechanical properties of the heart.Table 1Hearts Shear Wave Velocity, m/s Shear Modulus, kPaHypoperfused before 1.69 2.84Hypoperfused after 1.22 1.49Normal before 1.23 1.50Normal after 1.34 1.79S111540671 Feasibility and Reproducibility of Right Ventricular StrainMeasurement by Speckle-Tracking Echocardiography inPreterm InfantsPhilip Levy, 1 * Gautam Singh, 1 Tim Sekarski, 1 Aaron Hamvas, 1Mark Holland 1,2 1 Pediatrics, Washington University Schoolof Medicine, St Louis, Missouri USA; 2 Physics, WashingtonUniversity, St Louis, Missouri USAObjectives—The right ventricle (RV) is the dominant ventriclein premature and term neonates, and its function is an important determinantof the clinical status and prognosis of congenital and acquired cardiopulmonarypathologies. Myocardial strain and the strain rate represent2 sensitive measures of cardiac function. 2D speckle-tracking echocardiography(2DSE) is an angle-independent method for strain measurementbut has not been applied in preterm infants for assessment of RVfunction. The aim of this study was to evaluate the feasibility and reproducibilityof 2DSE-measured RV global longitudinal strain in preterm infantsand establish standardized methods for acquiring and analyzing strainmeasurements.Methods—2DSE (GE EchoPac) was used to measure the peakglobal longitudinal strain (pGLS) and strain rate (pGLSR) in the apical 4-chamber view of the RV in 50 preterm infants (27 ± 1 weeks at birth) at32 weeks postmenstrual age. Images were acquired with frame rates between60 and 100 Hz for 3 cardiac cycles and stored for offline analysis.Two observers measured the RV pGLS and pGLSR in 25 randomly selectedimages. Interobserver and Intraobserver reproducibility were assessedusing Bland-Altman analysis (relative bias, 95% limits ofagreement [LOA]), and the correlation was tested using linear regression.Results—Strain imaging was feasible from 85% of the acquisitions.Intraobserver 2DSE RV pGLS and pGLSR reliability demonstratedhigh reproducibility (bias, 4%; 95% LOA, –2.1 to +1.9; r = 0.98;P < .01; and bias, 6%; 95% LOA, –0.29 to +0.26; r = 0.94; P < .01, respectively).Interobserver 2DSE RV pGLS and pGLSR reliability alsoshowed high reproducibility (bias, 7%; 95% LOA, –4.1 to +3.9; r = 0.92;P < .01; and bias, 7%; 95% LOA, –0.41 to +0.42; r = 0.94; P < .01, respectively).Conclusions—Our study demonstrates high feasibility and reproducibilityof RV strain measurements by 2DSE in preterm infants andoffers specific recommendations for image acquisition and data analysisthat reduce measurement variability. Strain measurement by 2DSE offersa robust tool for the assessment of global RV function that is not achievedby conventional methods. (Supported by National Institutes of Healthgrants 1U01 HL101465 and R21 HL106417.)1541514 Statistical Comparison of Backscatter Coefficients for MATand 4T1 Tumors Across Multiple Ultrasound-Imaging SystemsDouglas Simpson, 1 * Nathaniel Hirtz, 1,2 William O’Brien Jr 21Statistics, 2 Bioacoustics Research Laboratory, Electrical andComputer Engineering, University of Illinois at Urbana-Champaign,Urbana, Illinois USAObjectives—Quantitative ultrasound measurements such as thebackscatter coefficient (BSC) have the potential to greatly enhance tissuecharacterization and identification of tumors. A balanced experiment wasconducted to compare consistency across transducers and efficacy for distinguishing2 well-characterized animal tumor types.Methods—The study included induced 4T1 and MAT tumorsin mice and rats. Animals were scanned with 5 different transducers witha target of 5 scan lines per tumor region of interest. BSCs were computedfor each scan. The resulting BSC data were analyzed across tumor typesand transducers using spatially dependent linear mixed model analysis,where the spatial dependence was between neighboring frequencies withinthe same scan line. The model allowed comparison of BSC curves fromtransducers with varying frequency ranges.Results—For 4T1 tumors, transducer differences were not statisticallysignificant. For MAT tumors, significant differences between
American Institute of Ultrasound in Medicine <strong>Proceedings</strong> J Ultrasound Med 32(suppl):S1–S134, 2013transducers were found. All 5 transducers detected significant differencesbetween tumor types either through a mean shift model or via changes incurve shape between tumor groups. Higher-frequency transducers producedsignificantly greater separation of mean BSC curves between MAT and4T1 tumors. Mean differences between tumor types were smaller than theinherent variability in the BSC curves as measured by the residual standarderror values, indicating a low signal to noise ratio for classification.Conclusions—All 5 ultrasound-imaging transducers were effectivein detecting significant differences between MAT and 4T1 tumors,either through mean shift or through shape changes. Higher frequencies inthe range above 8.5 MHz were more effective than lower frequencies in detectingtumor differences.1540921 Automatic Detection of Keratoconus From High-Frequency Ultrasound DataRonald Silverman, 1,2 * Raksha Urs, 1 Arindam RoyChoudhury,1 Timothy Archer, 3 Dan Reinstein 3 1 Ophthalmology,Columbia University Medical Center, New York, New YorkUSA; 2 Frederic L. Lizzi Center for Biomedical Engineering,Riverside Research, New York, New York USA; 3 London VisionClinic, London, EnglandObjectives—Keratoconus (KC), a corneal dystrophy characterizedby progressive corneal thinning and bulging, is currently detectedby optically determined corneal topography and curvature. The cornealepithelium, however, tends to remodel to smooth out irregularities in theunderlying stroma, potentially masking early KC topographic changes. Inthis report, we describe automated ultrasound detection of KC based on alteredepithelial thickness patterns.Methods—Corneas of 128 normal and 68 KC subjects (1 randomlychosen eye per subject) were scanned using the Artemis-1 (Arcscan,Inc, Morrison, CO) high-frequency ultrasound system. Scans areperformed with an optical fixation target and video monitoring of eye positionwhile the 50-MHz transducer is scanned in an arc such that curvaturein the focal plane approximately matches that of the corneal surface.Radiofrequency data are digitized at 500 MHz. Scans were acquired in 4planes at 0°, 45°, 90°, and 135°. Postprocessing consisted of automaticdetection of the corneal surfaces and the epithelial/stromal interface. Maps(100 × 100 at 0.1-mm intervals) of epithelial and stromal thickness werethen automatically analyzed to extract 87 features that might potentiallydifferentiate normal from KC eyes. Stepwise linear discriminant analysis(LDA) and neural network (NN) analysis using a radial basis kernel werethen performed. NN analysis was repeated 10 times with different randomtest sets (30% of cases).Results—Stepwise LDA produced a model consisting of 11features with sensitivity of 91.2%, specificity of 99.2%, and an area underthe receiver operating characteristic (ROC) curve of 98.5%. A leave-oneoutprocedure gave identical sensitivity and specificity. The NN showedaverage sensitivity of 93.5% and specificity of 97.4% for the training setand 88.8% and 97.5%, respectively, for the test set. The area under theROC curve was 97.8%.Conclusions—Our results show ultrasound-detected patternsin corneal layered topography to be very effective at distinguishing normalfrom KC corneas. Future studies will combine these methods withoptical data for early detection, which would allow early treatment by collagencross-linking and avoidance of potentially damaging corneal refractivesurgical procedures.Breast Ultrasound and ElastographyModerator: Abid Irshad, MD1538656 Correlation Between Parameters in Ultrasound-GuidedDiffuse Optical Tomography and 18 F-FluorodeoxyglucosePositron Emission Tomography/Computed Tomographyfor Breast CancerWoo Jung Choi,* Hak Hee Kim, Joo Hee Cha, Hee JungShin, Hyunji Kim Radiology, Asan Medical Center, Seoul,KoreaObjectives—The purpose of this study was to correlate parametersin ultrasound (US)-guided diffuse optical tomography and maximumstandardized uptake value in 18 F-fluorodeoxyglucose positron emissiontomography/computed tomography ( 18 F-FDG PET/CT).Methods—We retrospectively evaluated 228 patients (meanage, 46.9 years; range, 29–71 years) diagnosed with breast cancer betweenSeptember 2009 and February 2012. Both US-guided diffuse optical tomographyand 18 F-FDG PET/CT were performed. For each lesion, thetotal hemoglobin concentration (HBT) level and oxygen saturation (SO2)level were calculated, and the synthesis diagnosis index (SDI) was designedusing US-guided diffuse optical tomography. With 18 F-FDGPET/CT, the maximum standardized uptake value (mSUV) was calculated.We compared the parameters in US-guided diffuse optical tomographywith the mSUV of known malignant breast lesion on 18 F-FDGPET-CT using the Spearman correlation coefficient.Results—All 228 malignant lesions were primary breast cancers,and the histologic types included invasive ductal carcinoma (n =210), invasive lobular carcinoma (n = 4), invasive mammary carcinoma(n = 12), and metaplastic carcinoma (n = 2). Correlation between the SO 2level and mSUV was statistically significant (Spearman correlation coefficient= –0.280; P < .001). The HBT level and SDI showed a low correlationcoefficient with the mSUV (spearman correlation coefficients =0.049 and 0.072; P = .458 and .280, respectively).Conclusions—The SO 2level of US-guided diffuse optical tomographycorrelated well with the mSUV of 18 F-FDG PET/CT. A lowSO 2level in optical imaging may predict a high mSUV level on 18 F-FDGPET/CT, and it may serve as a useful tool for predicting the response rateafter neoadjuvant chemotherapy in breast cancer.1540665 Comparison of Strain and Shear Wave Without or With aQuality Measure in Evaluation of Breast MassesRichard Barr Radiology Consultants, Inc, Youngstown, OhioUSAObjectives—Shear wave imaging (SVI) in the breast codessome cancers as soft. Coding a malignancy as soft can be due to poor shearwave propagation. The addition of a quality measure (QM) that determinesif an adequate shear wave formed for accurate measurements. Theaim of this paper was to compare the predictive value of strain (elasticityimaging [EI]) and SVI without and with a QM.Methods—Patients scheduled for an ultrasound breast biopsyhad strain (EI) and SVI on a Siemens S2000 system modified to performSVI with a QM. Lesions were evaluated for shear wave velocity (V s ) andthe QM. The highest V s in the lesion or surrounding ring (if present) wasused. The V s was classified as benign (4.5 m/s).For strain, an EI/B-mode ratio of
Page 1 and 2: 2013Journal ofUltrasoundin Medicine
Page 5 and 6: Small-Animal Preclinical High-Frequ
Page 7 and 8: 2013 AIUM Award WinnersJoseph H. Ho
Page 9 and 10: 2013 AIUM Award WinnersDistinguishe
Page 11 and 12: Endowment for Education andResearch
Page 13 and 14: Rosa De Vermette, MD, RDCS,RDMS, RO
Page 15 and 16: Kee-Hak Lim, MDG. Sharat Lin, PhDTo
Page 17 and 18: David Stark, MDA. Thomas Stavros, M
Page 19 and 20: *Presenter of scientific paper with
Page 21 and 22: American Institute of Ultrasound in
Page 29: American Institute of Ultrasound in
Page 81 and 82:
American Institute of Ultrasound in
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154:
© Greater Phoenix CVB
show all

Official Proceedings - AIUM

Create successful ePaper yourself

Delete template?

Save as template?