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American Institute of Ultrasound in Medicine <strong>Proceedings</strong> J Ultrasound Med 32(suppl):S1–S134, 20131543325 Novel Quantitative Conventional-Frequency Detection ofCell Death In Vivo With Neoadjuvant Chemotherapy forLocally Advanced Breast CancerGregory Czarnota, 1 * Ali Sadeghi-Naini, 1 Omar Falou, 1 SaraIradji, 1 William Tran, 1 Michael Kolios 2 1 Radiation Oncology/Physical Sciences, Sunnybrook Health Sciences Center,Toronto, Ontario, Canada; 2 Physics, Ryerson University,Toronto, Ontario, CanadaObjectives—We have previously demonstrated that highfrequencyultrasound and spectral analysis can detect cell death. Here weinvestigated whether quantitative conventional-frequency (7-MHz) ultrasoundincorporating spectral analysis and textural parameters may be usedfor the same purpose in vivo in human patients receiving chemotherapy.Methods—A clinical study was undertaken investigating theefficacy of ultrasound to quantify cell death in tumor responses with cancertreatment. Patients (n = 60) with locally advanced breast cancer receivedanthracyline- and taxane-based chemotherapy treatments. Datacollection consisted of acquiring tumor images and radiofrequency dataprior to treatment onset and at 4 times during treatment (weeks 0, 1, 4, 8,and preoperatively). Digital low-frequency ultrasound data were collectedand sampled with a 15-bit dynamic range using an Ultrasonix-RP devicewith a 7-MHz central frequency (3–10 MHz, –6-dB range). Whole-mounthistology was obtained for all samples.Results—Data indicated that spectral ultrasound changes weresignificant at 4 weeks after the start of treatment. Increases of approximately9 dBr (±1.67) in ultrasound backscatter were observed in patientswho responded to treatment. Patients assessed as responding poorlydemonstrated significantly lower increases (2.3 ± 1.7 dBr). Increases in 0-MHz intercept followed similar trends, while increases in spectral slopewere observed from tumor regions demonstrating increases in tissueechogenicity. Textural analysis of parametric images indicated that featuressuch as homogeneity and contrast could detect responses as early as1 week after the start of treatment.Conclusions—This study demonstrates the potential of ultrasoundto quantify changes in tumors in response to cancer treatment administrationin a clinical setting. This approach may assist in thecustomization of cancer treatments facilitating switching from ineffectivetreatments to efficacious therapies.1540914 Nonlinear Modeling of the Canine Liver With IncreasingHepatic PressureVeronica Rotemberg, 1 * Brett Byram, 1 Mark Palmeri, 1,2Michael Wang, 1 Kathryn Nightingale 1 1 Biomedical Engineering,Duke University, Durham, North Carolina USA;2Anesthesiology, Duke Medical Center, Durham, North CarolinaUSAObjectives—Elevated hepatic venous pressure is associatedwith leading causes of death from advancing liver disease and is currentlymonitored using an invasive and expensive method. The mechanical behaviorof the liver during pressurization is not well understood. In thiswork, liver strain during hepatic pressurization was characterized usingsuccessively acquired 3D B-mode volumes and was compared with concurrentshear wave speed (SWS) estimates. An experiment was designedto elucidate liver nonlinear material properties by using volumetric imagingin unconstrained ex vivo canine livers to estimate the change in liverstrain with pressurization and compare this change in strain with simultaneousSWS estimates. The concurrent strain and SWS estimate informationis actively being used to develop a nonlinear material model forhepatic behavior with increasing portal venous pressure.Methods—Hepatic pressure was increased stepwise from 0 to20 mm Hg with 3D B-mode acquisition during each step at 3.2 volumes/susing a Siemens Acuson SC-2000 scanner and 4z1c matrix array transducer(Mountain View, CA). Displacements were calculated using 3Dcross-correlation and a 2.88 × 0.60 × 0.68-mm tracking kernel. 1 Strainswere estimated in a 20 × 12 × 12-mm region of interest (ROI). Six acousticradiation force impulse–based SWS estimates in the same ROI were generatedat the end of each step.Results—Increases in SWS and axial strain as a function of hepaticpressure as well as the relationship between axial strain and SWSestimates were developed. During portal venous pressurization, 10% increasesin axial strain corresponded to a 1.25-m/s increase in hepatic SWSestimates above baseline estimates at 0 to 5 mm Hg.Conclusions—Increases in axial strain and SWS estimates observedwith increasing hepatic pressure support the development of a nonlinearmechanical material model for the pressurized liver. This materialmodel may lead to noninvasive hepatic pressure characterization usingstiffness metrics.References1. Byram BC, et al. 3-D phantom and in vivo cardiac speckle trackingusing a matrix array and raw echo data. IEEE Trans Ultrason FerroelectrFreq Control 2010; 57:839–854.1514461 UroImage: A Prostate Tissue Characterization/ClassificationSystem Using Grayscale FeaturesGyan Pareek, 1 Rajendra Acharya, 2,3 Swapna Goutham, 4Vinitha Sree, 5 Ratna Yantri, 2 Roshan Martis, 2 Luca Saba, 6Ganapathy Krishnamurthi, 7 Giorgio Mallarini, 6 AymanEl-Baz, 8 Shadi Al Ekish, 1 Michael Beland, 9 Jasjit Suri 5,10 *1Section of Minimally Invasive Urologic Surgery, Warren AlpertMedical School, Brown University, Providence, Rhode IslandUSA; 2 Electronics and Computer Engineering, Ngee Ann Polytechnic,Singapore; 3 Biomedical Engineering, University ofMalaya, Kuala Lumpur, Malaysia; 4 Applied Electronics and Instrumentation,Government Engineering College, Kozhikode,Kerala, India; 5 Global Biomedical Technologies, Roseville,California USA; 6 Radiology, Azienda Ospedaliero Universitariadi Cagliari, Cagliari, Italy; 7 Mayo Clinic, Rochester, MinnesotaUSA; 8 Bioengineering, Speed School of Engineering,University of Louisville, Louisville, Kentucky USA; 9 Ultrasound,Rhode Island Hospital, Providence, Rhode Island USA;10Biomedical Engineering, Idaho State University, Pocatello,Idaho USAObjectives—Prostate transrectal ultrasound (TRUS) images canbe easily acquired in real time at lower cost and hence are widely used forprostate cancer (CaP) diagnosis. However, the prostate regions in TRUSimages are characterized by a weak texture, speckle, short grayscaleranges, and shadow regions. There is a need for image analysis frameworksthat effectively quantify the subtle textural changes in cancerousand noncancerous TRUS prostate images to accurately detect CaP. In thiswork, we have proposed an online computer-aided diagnostic systemcalled “UroImage” that classifies a TRUS image into cancerous or noncancerouswith the help of nonlinear higher-order spectra (HOS) featuresand discrete wavelet transform (DWT) coefficients.Methods—The UroImage system consists of an online systemwhere 5 significant features (1 DWT-based feature and 4 HOS-based features)are extracted from the test image. These online features are transformedby the classifier parameters obtained using the training data set todetermine the class label of the test image. We trained and tested 6 classifiers.The data set used for evaluation had 144 TRUS images, which weresplit into training and testing sets, and cross-validation was adapted fortraining and estimating the accuracy of the classifiers. The ground truthused for training was obtained using the biopsy results.Results—Among the 6 classifiers, using 3- and 10-fold crossvalidationtechniques, support vector machine and fuzzy Sugeno classifierspresented the best classification accuracy of 97.95% with equally highvalues for sensitivity, specificity, and positive predictive value.S61
American Institute of Ultrasound in Medicine <strong>Proceedings</strong> J Ultrasound Med 32(suppl):S1–S134, 2013Conclusions—Our proposed automated system uses a novelcombination of DWT and HOS features to adequately characterizeprostate TRUS images. On evaluation, the system presented high accuracyof 97.95% in detecting CaP. Thus, the preliminary results indicate that theUroImage system can be an adjunct tool to provide an initial diagnosis forthe identification of patients with prostate cancer.1540270 Quantitative Ultrasound as an Aid to Differentiate BenignFrom Malignant Breast MassesHaidy Nasief, Ivan Rosado-Mendez, James Zagzebski,Timothy Hall* Medical Physics, University of Wisconsin,Madison, Wisconsin USAObjectives—Ultrasound attenuation (Att), backscatter coefficients(BSC), effective scatterer diameter (ESD), and a scatterer size “heterogeneityindex”(HI) give useful insight into the nature of a breast mass.The purpose of this study was to evaluate the potential of these quantitativefeatures, both individually and in combination, to differentiate benignfrom malignant breast masses.Methods—Radiofrequency echo data from 26 patients scheduledfor ultrasound-guided biopsy of suspicious breast masses were obtained,along with conventional grayscale and color flow images. Scanswere done using a Siemens Acuson S2000 equipped with an 18L6 lineararray transducer. Beam-steered acquisitions ranging between –20° to 20°were obtained in both radial and antiradial planes projecting through themass. Att and BSC within masses were measured using the referencephantom method. ESDs were estimated using the BSC vs frequency dataand a Gaussian form factor. HI was characterized using the SD among theESD estimates (ignoring correlations among them). Isotropic features ofthe masses were studied by computing power law fits of Att vs frequencyat each beam-steering angle. Combinations of quantitative ultrasound parameterswere examined with a Bayesian classifier to estimate those withthe strongest influence on characterization.Results—The mean Att in dB/cm-MHz was slightly higher forcarcinomas (1.3 ± 0.7) than fibroadenomas (1.1 ± 0.5), the average valueof the ESD was smaller for carcinomas (83.1 ± 9.8 µm) than for fibroadenomas(97.8 ± 13.1 µm), and carcinomas exhibited lower HI thanfibroadenomas. Surprisingly, both tumor types exhibited a certain degreeof anisotropic behavior. However, considerable overlap exists in backscatterand attenuation properties of benign and malignant masses. Using onlypairs of parameters to classify the disease type performed relatively poorly,but the performance of a Bayesian classifier combining 3 parameters (Att,ESD, and HI) was cautiously encouraging (all classified correctly but ona very limited data set).Conclusions—Att, ESD, and HI show promise for characterizingbreast masses. Very promising results are possible using combinationsof these 3 parameters.1536102 Stochastic Hidden Markov Model–Based FilteringAlgorithm for Tracking Shear Waves Through DisparateMedia in Electrode Vibration ElastographyAtul Ingle, 1 * Tomy Varghese 1,2 1 Electrical and ComputerEngineering, 2 Medical Physics, University of Wisconsin, Madison,Wisconsin USAObjectives—Much research effort in quantitative ultrasoundelastography has been directed toward methods for setting up shear wavesin tissue and modeling wave propagation characteristics. However, dataprocessing has been mostly limited to using off-the-shelf function-fittingalgorithms. The present work proposes a specialized noise-filtering algorithmto improve boundary delineation while reducing the risk of excessivesmoothing.Methods—A shear wave pulse traveling through dissimilarmedia is assumed to have constant velocity while in the same medium,whereas its velocity changes abruptly when it crosses an interface. Ultrasounddisplacement estimates are used to get the time of arrival (TOA) ofthe wave pulse at different locations. The noiseless TOA plot is assumedto be piece-wise linear with unknown transition points. The noisy data aredescribed using a hidden Markov model whose hidden states are the noiselessTOA values and observed states corrupted by Gaussian noise. A particlefilter is then used to unravel the hidden states. An electrode vibrationelastography phantom is used, which consists of 3 different media. A needlebound to an inclusion in the phantom and attached to an actuator isused to set up shear waves.Results—Visual boundary delineation is improved because thisalgorithm uses probabilistic prior information of wave pulse propagation.Mean shear wave velocity estimates are within 1 m/s of those obtainedusing a commercial shear wave imaging system.Conclusions—Model-based algorithms have a potential to significantlyimprove results in shear wave elastography quantitatively interms of estimates of mechanical properties and qualitatively in terms ofthe visualization of stiffness images. (Supported by National Institutes ofHealth grants R01CA112192-05 and R01CA112192-S103.)Table 1Shear Wave Velocity, m/s Young’s Modulus, kPaMechanicalROI EVE SSI EVE SSI TestingInclusion 3.8 ± 2.2 2.8 ± 1.1 57.2 ± 70 24.2 ± 5.8 54.4 ± 0.1Partially ablated 2.0 ± 0.2 2.3 ± 0.8 11.9 ± 2.6 13.3 ± 3.5 21.5 ± 0.3Background 1.3 ± 0.2 1.3 ± 0.4 5.0 ± 1.9 4.8 ± 0.5 3.7 ± 0.1EVE indicates electrode vibration elastography; ROI, region of interest; and SSI,supersonic shear imaging.1540426 Viscoelastic Strain Response Ultrasound Assessment of SerialChanges in the Viscoelastic Property and Compositionof Human Dystrophic Muscle In VivoMallory Scola, 1 Melissa Caughey, 2 Diane Meyer, 3 ReginaEmmitt, 3 James Howard, 2,4 Manisha Chopra, 4 CaterinaGallippi 1 *1 Joint Department of Biomedical Engineering,2Medicine, 3 Physical and Occupational Therapy, 4 Neurology,University of North Carolina, Chapel Hill, North Carolina USAObjectives—In Duchenne muscular dystrophy (DMD), wheremuscle tissue undergoes necrosis and is replaced by fat and collagen, delineatingthe complex and poorly understood disease process and monitoringresponses to novel therapies may be facilitated by imaging muscleviscoelasticity. Viscoelastic strain response (ViSR) ultrasound is a methodfor quantitatively evaluating the relaxation time constant, τ, in the Voigtmodel. The objective of this work is to demonstrate ViSR’s clinical relevanceto monitoring dystrophic muscle degeneration over time. We hypothesizethat ViSR ultrasound detects changes in percent fat/necrosiscomposition in DMD muscles that correspond to altered physical performance.Methods—ViSR ultrasound was performed on a 5-year-old boywith DMD at baseline and at 4-month follow-up using a Siemens AcusonAntares imaging system equipped for modifiable beam sequencing and aVF7-3 transducer. The acquired ViSR data were processed to calculate τ,and parametric 2D ViSR τ images were rendered. Fat/necrosis compositionwas calculated as the percent muscle area with ViSR τ values abovean empirically determined threshold. Within 1 hour following each imagingepisode, the boy underwent standardized timed function tests. ViSRoutcome was compared to physical performance.Results—See Table 1.Conclusions—ViSR ultrasound detected a 39% increase frombaseline to 4-month follow-up in fat/necrosis composition in the rectusfemoris (RF), a 5% decrease in the sartorius (SART), and a 7% increasein the gastrocnemius (GAST), which is consistent with expected phenotypicvariation in these muscles for a 5-year-old boy. The ViSR changeS62
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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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