Official Proceedings - AIUM

American Institute of Ultrasound in Medicine Proceedings J Ultrasound Med 32(suppl):S1–S134, 2013Methods—In a cohort of symptomatic patients referred fromneurosurgery, 3DUS of the carotid arteries was conducted using a vascularultrasound system (iU22; Philips Medical Systems) equipped with avolumetric mechanical high-resolution linear array transducer for 3D imaging.We employed a 3DUS imaging method to allow high-detail studiesin mild, moderate, and severe stenotic plaques. Constructed 3D plaqueimages were quantified using the internal plaque echo texture, volume,and surface morphology and evaluated by 2 independent observers usingour own classification protocol.Results—At the time of abstract submission, final data were notyet available; however, preliminary results indicate that 3DUS for plaquecharacterization was significantly better in mild to moderate imaging, possiblydue to the fluid-filled lumen acting as a substantial acoustic transmissionfor optimal plaque visualization. Higher-grade stenoses (>70%)were difficult to assess; however, proximal and edge surface imaging wasdiagnostic. These preliminary results indicate that our 3D approach may bea sensitive tool in the identification of early vulnerable markers in lowergradedstenoses, possibly identifying early prediction of stroke.Conclusions—Preliminary results show a high sensitivity andnegative predictive value of carotid plaque 3DUS in mild to moderatestenosis and can reliably characterize the surface, volume, and ulcerations.The sensitivity decreased with the severity of stenoses. 3DUS carotidplaque quantification may serve as an important clinical screening tool inearly onset of significant carotid disease, for high-risk patients, and forthose without known significant carotid disease.1540523 Practical Uniformity Evaluation of Ultrasound Systems:Tips and PitfallsDonald Tradup,* Nicholas Hangiandreou, Scott StekelRadiology, Mayo Clinic, Rochester, Minnesota USAObjectives—We have found uniformity evaluation (UE) to bethe single most effective imaging test to ensure proper function of medicalultrasound (US) imaging systems. In this presentation, we will describeour process for efficient and effective UE.Methods—Display quality assessment and mechanical inspectionof the imaging system should occur prior to UE. Begin the UE by annotatingthe image with the device identification and visually inspectingin-air images. Some scan controls should be set to standard values (output,dynamic range, depth, compounding, transmit frequency, and focus)as will be described in the presentation. Gain and time-gain compensationare visually optimized. Next, acquire clips of a phantom. These clipsshould show a dynamic speckle pattern across the entire transducer face.We use a previously described custom, flexible, liquid phantom. Tips foroptimal use of this phantom will be described. Commercial phantoms maybe used, but multiple clips may be needed to test the complete face ofcurved arrays. Store 3 phantom clips (to guard against false-positive findingsdue to poor coupling) and 1 in-air clip. If possible, compute medianimages from each clip, and inspect these for artifacts. Review of medianimages acquired at acceptance (or use of subtracted median images) willreduce the incidence of false-positives. Any artifacts observed at any pointduring testing should be debugged to rule out poor coupling with the phantom,dirt/debris on the transducer face or connector, or scanner port, toidentify mechanical damage, cable-flex issues, and differentiate port vstransducer problems. The severity of reproducible artifacts should be determinedby assessing visibility of the artifact when scanning anatomy andthe size and location of the artifact.Results—This UE approach has allowed us to detect artifactsin our US practice with good sensitivity and specificity, and staff efficiency.For ≈10% to 15% of transducers, a potential artifact is noted duringinitial testing that is discounted during debugging.Conclusions—Artifacts and equipment problems can be effectivelyidentified using a standard UE protocol. The debugging step isessential for minimizing the incidence of false-positives.1540556 Utility of the Prefrontal Space Ratio to Screen for Trisomy21 in a Racially Diverse Population: A Pilot StudyBarrie Suskin Kaplan, 1,2 Anne Marie Roe, 2,3 Komal Bajaj 2,3 *1Obstetrics and Gynecology, Montefiore Medical Center, Bronx,New York USA; 2 Albert Einstein College of Medicine, Bronx,New York USA; 3 Obstetrics and Gynecology, North BronxHealthcare Network, Bronx, New York USAObjectives—The characteristic facial features of trisomy 21, includingthe dorsal displacement of the edge of the maxilla and thickeningof the prenasal skin, have been well described. The prefrontal space (PFS)ratio capitalizes on these changes and has been shown to be an effectivescreening marker for trisomy 21 when calculated from midsagittal 2Dsonographic images of the fetal profile in the second and third trimesters.These studies, which have been performed exclusively in Caucasian populations,reported a mean PFS ratio in euploid fetuses of 0.97. As facialmorphology varies among different racial groups, it is plausible that thePFS ratio may differ in non-Caucasian fetuses. The objective of this studywas to evaluate the PFS ratio of euploid fetuses of African American decentto determine whether this difference may exist.Methods—The PFS ratio was calculated retrospectively fromstored 2D images of euploid African American fetuses in the second andthird trimesters. These prenatal sonograms were performed at an urbanacademic maternal-fetal testing unit under strict supervision by reproductivegenetics and maternal-fetal medicine specialists. The cases weredrawn from chronologic birth records from our institution. Images wereexcluded if the fetal profile was not truly midsagittal or if the anterioredges of the maxilla and skin were not clearly identifiable. Other data includingthe presence of the nasal bone, maternal age, gestational age, andethnicity were also collected.Results—Mean maternal age was 29.3 years. Median gestationalage at the time of ultrasound examination was 20 weeks 4 days (18weeks 3 days–25 weeks 4 days). The mean PFS ratio was 0.61 (SD, 0.21).In a subset of fetuses with a hypoplastic or absent nasal bone, the meanPFS ratio was 0.51 (SD, 0.17).Conclusions—Though not statistically significant, the prefrontalspace ratio in African American euploid fetuses trended lower thanthat reported in euploid Caucasian fetuses in the literature. This pilot studysuggests that different racial groups may have different normal prefrontalspace ratios. We plan to expand this study as well as assess the prefrontalspace ratio of other groups to establish accurate normal values for a raciallydiverse population.1540570 An Objective Tool to Evaluate Ultrasound Image Quality:The Ultrasound Standardized Assessment ToolCreagh Boulger,* Katherine Pollard, David Bahner EmergencyMedicine, Ohio State University College of Medicine,Columbus, Ohio USAObjectives—Evaluation of the skill of a sonographer requiresobjective assessments of his or her ultrasound scans. However, little literatureexists to define a high-quality ultrasound image. The purpose of thisstudy is to develop a standardized tool (Ultrasound Standardized AssessmentTool [USAT]) to assess ultrasound image quality and perform a pilotreliability study of the tool.Methods—A specific USAT was developed for each core emergencyultrasound application: trauma, intrauterine pregnancy, abdominalaortic aneurysm, cardiac, biliary, urinary tract, deep venous thrombosis,soft tissue/musculoskeletal, thoracic, ocular, and procedural guidance. TheUSAT uses a series of objective yes-or-no questions in conjunction witha difficulty rating of each view to produce a score. Ten beginning sonographers(first-year medical students in our institution’s introductory ultrasoundtraining program), 10 experienced sonographers (fourth-yearmedical students in our institution’s honors ultrasound course), and 5 expertsonographers (ultrasound-credentialed faculty members at our institution)S108