DK2985_C000 1..28 - AlSharqia Echo Club

6Imaging Artifacts and PitfallsROBERT AMYOT, MARIA DI LORENZO, RÉAL LEBEAU, CLAUDE SAUVÉUniversity of Montreal, Montreal, CanadaI. Introduction 121II. Image Features and Artifacts 121A. Reverberation 121B. Aliasing 123C. Ghosting 124D. Mirror Images 124E. Near-Field Clutter 125F. Range Ambiguity 125G. Refraction 126H. Shadowing 127I. Electrocautery 127J. Side Lobes 127III. Misinterpretation of Normal Structures 129A. Trabeculations 129B. False Tendons 129C. Pectinate Muscles 130D. Moderator Band 132E. Lipomatous Hypertrophy of theAtrial Septum 132F. Eustachian Valve 132G. Chiari Network 133IV. Echo-Free Spaces 133A. Persistent Left Superior Vena Cava 133B. Transverse Sinus of Pericardium 134V. Color Flow Doppler 135A. Physiologic Regurgitation ofNative and Prosthetic Valves 135B. Gain 136C. Frequency 137D. Velocity Scale and Baseline Shift 137E. Sector Depth 138VI. Summary 138References 138I. INTRODUCTIONKremkau and Taylor (1) define imaging artifacts as displayphenomena not properly representing the structures to beimaged. Imaging pitfalls include artifacts, but also relateto misinterpretation of a properly represented structure,whether normal or pathologic. These obstacles to accurateimage analysis are commonly encountered during transesophagealechocardiography (TEE). They must be recognizedin order to avoid potentially serious errors. Ininexperienced hands, this powerful diagnostic instrumentmay result in blunders. Understanding the types andmechanisms of echocardiographic artifacts depends onexpertise and familiarity with this imaging modality, aswell as maintenance of competency. This chapterfocuses on the most prevalent artifacts and pitfalls encounteredduring TEE.II. IMAGE FEATURES AND ARTIFACTSA. ReverberationReverberations result from multiple reflections of theultrasound beam before returning to the transducer. Asthe imaging system assumes that the backscattered echosignal strokes an object located within the ultrasound121