Lower extremity swelling: computerized tomography following negative venography

Comparison of characteristic CT findings of lymphedema, cellulitis, and generalized edema in lower leg swelling

To determine the different computed tomography (CT) findings of lymphedema, cellulitis, and generalized edema in the lower leg. CT images of 44 patients with confirmed lymphedema (n = 19), cellulitis (n = 11), or generalized edema (n = 14) were retrospectively reviewed. The following characteristics were evaluated: extent of edema, laterality, skin thickening, honeycombing, taller than wide appearance, muscle edema, conglomeration of septum of fat lobule, fluid collection, fascial enhancement, inguinal lymph node (LN) enlargement, medullary fat obliteration of inguinal LN, trunk subcutaneous edema, and bone marrow edema. Fisher's exact test with Bonferroni correction was used for multiple comparisons. Honeycombing and taller than wide appearance of fat lobules were more common in lymphedema (P < 0.01). Fat obliteration of inguinal LN and inguinal LN enlargement at the affected side were more common in cellulitis (P < 0.01). Bone marrow and subcutaneous edema of the trunk were more common in generalized edema (P < 0.01). Honeycombing is commonly seen in lymphedema, but is not a specific finding. Inguinal LN enlargement is a specific sign of cellulitis. Truncal edema and bone marrow edema were specific findings of generalized edema.

Spiral CT venography of the lower extremities by injection via an arm vein in patients with leg swelling

The purpose of this prospective study was to assess the role of spiral CT venography (CTV) via an arm vein injection in the detection of causes of leg swelling. 42 consecutive patients with leg swelling were studied with indirect spiral CTV and ultrasound (US). CT parameters were as follows: 5 mm beam collimation; 7-10 mm s(-1) table speed; and 2-3 mm reconstruction. Two consecutive spiral scans with a 40 s exposure time were performed from the pelvis to the knee. One bolus of 150 ml non-ionic contrast medium was injected at a rate of 3 ml s(-1) by a power injector via an arm vein. The delay times to the first and second scans were 120 s and 180 s, respectively. Spiral CTV demonstrated not only deep vein thrombosis (DVT) (n=12) but also other abnormalities (n=25). US showed DVT (n=10) and some other abnormalities (n=5). The sensitivity and specificity of spiral CTV for femoropopliteal DVT, as compared with US, were both 100%. Two cases of DVT in the left common-external iliac vein (iliac vein compression syndrome) detected by spiral CTV were not confirmed by US. We were able to evaluate DVT above the knee with this method. Indirect spiral CTV showed promise for the diagnosis of DVT and other soft tissue diseases in patients with leg swelling.