Biometry of the infrarenal inferior vena cava measured by computed tomography. Clinical applications.

In a previous study based upon the cavography of 100 patients, we determined that the average diameter of the infrarenal inferior v. cava (IIVC) was 21.3 mm (range 10-31 mm) at its end [1]. We discuss the value of different methods to measure IIVC, and particularly computed tomography (CT) scans reviewed in our department. It showed that the largest diameter of IIVC was not in a frontal plane and the width observed in a cavography was in fact the projection of a transverse diameter on the film. The real diameter of the IIVC is larger than that showed by cavography. This present study shows the results of measurements of the IIVC obtained from 50 consecutive CT scans. The average transverse diameter is 24.26 mm (range 14-33.3). The average anteroposterior diameter is 13.4 mm (range 5-22) and the average angle alpha between the transverse diameter and the frontal plane is 30 degrees 45' (range 12 degrees-55 degrees). We discuss the different methods of measurement of IIVC and we conclude that at present, CT scan is one of the most reliable methods to measure the real diameter of IIVC.