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Axial oblique left ventriculography allows unique visualization of acquired and congenital cardiac lesions. However, validation of the accuracy of left ventricular (LV) volume with axial oblique projections is limited and clouded by orthogonal violations between biplane projections. Biplane cineradiographic volume measurement of 17 LV casts employing the axial projection 35 degrees right anterior oblique/55 degrees left anterior oblique/30 degrees cranial (35 degrees RAO/55 degrees LAO/30 degrees Cr) was performed and compared to the conventional postero-anterior/lateral (PA/Lat) and 30 degrees right anterior oblique/60 degrees left anterior oblique (30 degrees RAO/60 degrees LAO) views. LV volume was calculated from biplane cineradiograms by area length and Simpson's rule method. True LV volume by water displacement was 33 +/- 28 (mean +/- S.D.), range 15 to 112 ml. LV cast volume calculated by the area length method from cineradiograms was overestimated (p less than 0.002) but no different by Simpson's rule method (pNS). The ideal correlation was best approximated by the 35 degrees RAO/55 degrees LAO/30 degrees Cr biplane view calculated by Simpson's rule, r = 0.99, y = 3.5 + 0.9x, and standard error of estimate (SEE) = 4.3 ml. Biplane LV angiography with the axial projection permitted accurate LV volume measurement, and Simpson's rule provided the best representation of true volume.

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Right Coronary Angulated Views TO THE EDITORThe article Right Coronary Angiography: Optimal Utilization of Sagittally Angulated Views makes interesting reading [l]. I, however, like to differ from the authors in their basic concept of sagittal angulation.Cranial and caudal views for coronary angiography have been in vogue for quite some time, but the craniocaudal tilts have been made in the sagittal plane, and so the term sagittally angulated views [2]. Also, it is to be realized that while making any sagittally angulated craniocaudal view, there is a limit to the degree of tilt that can be given, which is usually in the range of 40°-45", beyond which the image intensifier starts touching the head or abdomen of the patient, as the case may be, and cannot be tilted any further. The authors, on the other hand, have very conveniently given cranial tilts of 60"-80" and even 90" in RAO and caudal tilts of 70" in LAO. This has been made possible only because in a true sense it is not a "sagittal" cranial tilt that has been given by them, but a rotation in the coronal plane, which is being done by the L arm pivoted on the floor.The authors' point of RAO cranial view for better visualization of the crux and distal RCA branching without foreshortening and overlap is well taken, but in my opinion this effect can be brought out by about 30"-35" of sagittal cranial tilt, and no more, as described earlier by Elliot et al. [3]. The advocation of LAO caudal view for better visualization of ostium and proximal RCA does not sound very convincing and is also not evident from the single illustration shown in their Fig. 3B. In fact, their straight LAO view has profiled the ostium of RCA better than the caudally tilted LAO view, where the proximal 1-2 cm of RCA has in fact become more end-on and almost completely overlapped over the distal catheter tip. I presume that this would depend on the degree of suprainferior orientation of the proximal RCA.Second, one finds it difficult to understand the sequence of illustrations shown in Fig. 2, which shows a straight RAO with gradually increasing "so called" cranial tilt from 25", 50", to 90". It is simple logic that whenever such a sequence of pictures with graded angulation is taken the in-between pictures have to be a transition between the first and the last. This is not evident, however, by any means in their sequence. The patient's spine, seen tilted slightly to the left in the first so-called straight RAO view ( Fig. 2A), surprisingly becomes straight in Fig. 2B, where 25" cranial angulation has been added and again is seen tilted in the same basal direction when the cranial tilt has been made 50" (Fig. 2C) and, finally, is seen tilted in the opposite direction, when still further cranial tilt of 90" (Fig. 2D) is given. Also the authors' use of the term X-Ray camera interchangeably for X-ray tube is incorrect, as camera is the picture-taking device and is always behind the image intensifier above the patient table, and not beneath. REFERENCES 1. Kleiman JH, Jukas J, Cohen HM: Right ...