title: Problems in ultrasonic estimates of septal thickness.
abstract: Problems related to cardiac anatomy and ultrasonic instrumentation affect the accuracy of echographic identification of endocardial echoes. A cadaver model and 13 patients were studied, with direct identification or with the aid of echographic contrast techniques, to identify accurately the endocardial echo. The study showed that (1) echographic contrast agents delineate an endocardial echo in the central portion of the ultransonic beam; (2) a specular reflector exists within the right ventricular cavity; (3) specular reflectors within the septum may give the false appearance of border-forming echoes; (4) septal thickness varies by 1 to 5 mm after the endocardial echo has been identified by the contrast agent; and (5) spurious echoes, related to a wide beam angle, can be confused with the endocardial echo. In light of these problems, three criteria were utilized for endocardial echo identification: the prominent notch in the left septal echo, the specular quality of the right septal echo, and the association of multiple myocardial echoes moving in parallel. With these criteria, the endocardial echoes in 11 of the 13 patients could be accurately identified without the use of a contrast agent. The identification of these problems should provide helpful guidelines in developing more accurate and reproducible criteria for septal thickness measurements.
mesh_terms: D002102:Cadaver; D003287:Contrast Media; D004452:Echocardiography / Q000295:instrumentation / Q000379:methods*; D004699:Endocardium; D006346:Heart Septum / Q000033:anatomy & histology*; D006801:Humans
chemical_list: D003287:Contrast Media