AJR Am J Roentgenol 2001 May;176(5):1281-5
Combined ct venography and pulmonary angiography: how much venous
enhancement is routinely obtained?
Bruce D, Loud PA, Klippenstein DL, Grossman ZD, Katz DS.
OBJECTIVE. Combined CT venography and helical pulmonary angiography is a new diagnostic
test that permits radiologists to check both the pulmonary arteries for embolism and the
deep veins of the abdomen, pelvis, and legs for thrombosis in a single examination. The
purpose of this study was to determine the degree of venous enhancement routinely obtained
using this combined CT examination. MATERIALS AND METHODS. We identified all patients at a
single institution who, during a 29-month period, had symptoms suggestive of pulmonary
embolism and who underwent CT venography and helical pulmonary angiography. The
examinations were performed after the patients received a rapid (3-5 mL/sec) IV injection
of 150 mL of nonionic contrast medium (240 mg I/mL). CT venography of the abdomen, pelvis,
and lower extremities was performed as follows: Beginning 3 min after the start of
contrast medium infusion for helical CT pulmonary angiography, 1-cm axial images obtained
at 5-cm intervals were acquired from an area ranging from the diaphragm to the calves.
Patients who had evidence of deep venous thrombosis on CT scans were excluded from further
analysis. The venous portions of the remaining 429 examinations were retrospectively
reviewed at a CT console or workstation by one of two radiologists, and Hounsfield unit
measurements were recorded from the inferior vena cava as well as from the right and left
external or internal iliac, common femoral, superficial femoral, and popliteal veins. A
single Hounsfield unit measurement was obtained from the center of each vessel using a
region of interest that was approximately half the diameter of the vessel. Mean Hounsfield
unit measurements were then calculated for these venous stations. RESULTS. Mean Hounsfield
unit measurements at the inferior vena cava and at the right and left external or internal
iliac veins were 97, 95, and 95 H, respectively. Mean measurements at the common femoral
veins were 95 H for both the right and left; the mean measurements at the superficial
femoral veins were 91 H for both the right and left, and those at the popliteal veins were
97 H for the right and 94 H for the left. CONCLUSION. CT venography of the abdomen,
pelvis, and lower extremities begun 3 min after the start of contrast medium infusion for
helical CT pulmonary angiography routinely produced high mean levels of venous
enhancement.
PMID: 11312195
