AJR:180, April 2003 1093 he combination of CT venography and pulmonary angiography is now widely performed for screening both the pulmonary arteries and the deep veins of the lower limbs and pelvis to diagnose pul- monary embolism and deep venous thrombosis. Many parameters, such as cardiac output, pe- ripheral arterial disease, and dehydration, limit venous enhancement. The objective of this study was to find a way to increase venous en- hancement without increasing the iodine dose. By compressing superficial veins, elastic stockings might improve deep venous en- hancement and, as a result, increase diagnos- tic performance. This technique commonly used in conventional venography to increase deep vein opacification [1] has not been tested on CT venography. The aim of this prospec- tive and preliminary study was to evaluate whether using elastic stockings could increase lower limb deep vein enhancement in patients without deep venous thrombosis. Materials and Methods Materials Oral informed consent was obtained according to the requirements of the institution’s ethics com- mittee. Between April 2, 2000, and July 13, 2000, we prospectively enrolled 60 consecutive patients who underwent pulmonary CT angiography for suspected pulmonary embolism. Among the study population, the first 30 patients, constituting group 1, underwent combined CT venography and pul- monary angiography without elastic stockings. The last 30 patients, constituting group 2, under- went the same examination with elastic stockings. Group 1 consisted of 17 men and 13 women with a mean age of 53 years (range, 21–85 years). Group 2 consisted of 15 men and 15 women with a mean age of 59 years (range, 24–83 years). CT venography was performed with a LightSpeed QX/i CT scanner (version 3.1; General Electric Med- ical Systems, Milwaukee, WI). In group 2, we used three sizes of tubular elastic stockings (Tubigrip; Se- ton Healthcare Group, Oldham, England) selected by the CT technician according to the patient’s weight (6.25-cm-diameter bandage for patients with a weight < 65 kg, 7.5-cm-diameter bandage for pa- tients’ weight ranging from 65 to 90 kg, and an 8.75- cm-diameter bandage for patients’ weight > 90 kg). The stockings were positioned to cover the lower ex- tremities from ankle to mid thigh. CT pulmonary an- giography was performed with a single helical acquisition from the cardiac base to the aortic arch during one breath-hold. Scanning began 15–20 sec after the start of the contrast injection depending on the patient’s age (15 sec for patients < 60 years old and 20 sec for older patients). CT parameters in- cluded 1.25-mm collimation and 7.5-mm/sec table speed using a pitch of 6 (120 kV, 200 mA). The dura- tion of the acquisition was approximately 12 sec, and the number of images obtained was approximately 120. We used an injection protocol of 120 mL of io- pentol (Imagopaque [300 mg I/mL]; Nycomed, Mu- nich, Germany) administered through an antecubital vein according to a biphasic injection: 80 mL at 3 mL/sec and 40 mL at 1 mL/sec. Scanning of the pelvis and the lower limbs be- gan 210 sec after the start of the injection. The venous images were obtained from mid calves to iliac crests, with a 2.5-mm collimation and 7.5- mm/sec table speed, using a pitch of 3, 100 kV, and 170 mA. Five-millimeter-thick images were reconstructed with a 5-mm interval. The duration of this venous imaging was approximately 70 sec, and, according to the patient’s height, approxi- mately 220 images were reconstructed. Methods Density measurements were obtained by a single radiologist who recorded the venous densities ex- pressed as mean ± standard deviation in Hounsfield units at three levels for each patient: in the popliteal vein just above femoral condyles (Fig. 1), in the superficial femoral vein just before the profound femoral vein ostium, and in the external iliac vein at the level of the sacroiliac joints. A cir- cular region of interest was positioned in the vein so that its diameter was approximately 50% less than the diameter of the vein to reduce partial vol- Optimization of Multidetector CT Venography Performed with Elastic Stockings on Patients’ Lower Extremities: A Preliminary Study of Nonthrombosed Veins Yasmine Abdelmoumene 1 , Patrick Chevallier, Ghassan Barghouth, François Portier, Salah Dine Qanadli, Francesco Doenz, Pierre Schnyder, Alban Denys Received July 10, 2002; accepted after revision September 12, 2002. 1 All authors: Department of Radiology, University Hospital, Rue du Bugnon, 1011 Lausanne, Switzerland. Address correspondence to Y. Abdelmoumene. AJR 2003;180:1093–1094 0361–803X/03/1804–1093 © American Roentgen Ray Society Technical Innovation T Downloaded from www.ajronline.org by 52.73.204.196 on 05/18/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved