LEFT-VENTRICULAR REGRESSION EQUATIONS FROM SINGLE PLANE CINE AND DIGITAL X-RAY VENTRICULOGRAMS REVISITED

For the assessment of left ventricular volume from X-ray ventriculogra ms, widely known regression equations are used to correct for the irre gular shape of the left ventricular lumen and the presence of the papi llary muscles and trabeculations. These regression equations were deri ved in the late nineteen sixties and seventies. With all the changes i n X-ray technology that have taken place over the past 20-30 years, th e question was raised whether these regression equations were still va lid. Therefore, 23 left ventricular casts of known volume were imaged in RAO20, RAO30 and RAO40 angiographic views and recorded on 35 mm cin efilm as well as in digital format. All the frames were traced manuall y by two observers and the volumes calculated by the Area Length and S impson Rule approaches. The following conclusions could be drawn: inte r- and intra-observer variations were small (systematic differences < 1.5 mi; random differences < 2.9 mi) and statistically not significant ; the regression equations are virtually the same for the RAO20, RAO30 and RAO40 views under the different circumstances; the Area Length me thod was associated with slightly smaller values for the standard-erro r-of-the-estimate (SEE) suggesting a slight preference for this approa ch versus the Simpson Rule; significant differences were found between the cinefilm and digital regression equations; and the following new regression equations are proposed, which indeed differ significantly f rom the earliest proposals and less from the monoplane formulas propos ed by Kennedy & Lange in the 1970s: [GRAPHICS]