CT study stirs debate about optimal varicose vein modality

Korean researchers find 3D CT scans offer a comprehensive view of complex varicose veins in the lower extremities, a practice that U.S. doctors find troubling.

A study appearing in the October American Journal of Roentgenology (2008;191:1186-1191) examined 100 patients with varicose veins at the Seoul National University Hospital using 3D CT. Dr. Jin Wook Chung and Dr. Whal Lee from the radiology department at the Institute of Radiation Medicine in Seoul found varicose vein visualization to be excellent in 76% of patients, fair in 21%, and poor in 3%.

Three-D imaging creates a road map of the superficial venous system for the sonographic evaluation of functional anatomy and improves the performance of Doppler sonography, Chung said in an interview.

Several U.S.-based radiologists asked to assess the findings, however, advised against CT use for varicose veins because of the radiation risk.

"Although CT does provide nice imaging, its ability to allow specific analysis for physiologic reflux and perforator dynamics is less than with duplex ultrasound, and the significant radiation dose with CT should limit its use to (perhaps) problem solving," said Dr. Ellen Yetter, an interventional radiologist at Saint Luke's Radiology Group in Kansas City, MO.

Chung and colleagues noted in the study that they turned to CT because duplex sonography can miss deep-seated varicose vein pathways and major perforators.

Duplex sonography is adequate when it comes to gaining insight about varicose veins, according to Yetter.

"I disagree with them and believe that one can gain more information from a duplex ultrasound done correctly than from a CT," she said.

She added that CT is complementary at best and should be used only to solve problems. Besides radiation risk, CT is more expensive than ultrasound, which makes it a less enticing modality.

Dr. Neil Khilnani, an associate professor of clinical radiology at Weill Cornell Medical College in New York City, argued that CT is rarely superior to ultrasound for evaluating varicose veins.

"There are some less typical pathways of reflux or venous hypertension that might benefit from CT," he said.

Other instances that may call for CT include obstructed veins in the pelvis or abdomen from thrombus or extrinsic compression, venous malformations - particularly recurrences after prior treatment - and ovarian vein reflux to determine its possible relationship with leg varicose veins.

These conditions, however, represent a small fraction of the causes of varicose veins, and a contrast-enhanced MR venogram would work better since there is no radiation risk, Khilnani said.

Chung countered that though duplex sonography is the current standard of care, its accuracy has never been critically evaluated because other competing diagnostic modalities have been lacking.

"CT venography provides a comprehensive and objective overview of the venous system of the lower extremity - from the deep to superficial veins; from the IVC and deep pelvic veins to calf veins; and from 2D cross-sectional or maximum intensity projection images to 3D pictures. CT venography is particularly useful in patients with unusual and complex varicosities," he said.

Chung told Diagnostic Imaging that physicians will soon realize how useful CT is when it comes to understanding venous diseases in the lower extremities. He expects more papers to be published in the future.

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