High-resolution MDCT of pulmonary septic embolism: evaluation of the feeding vessel sign.
OBJECTIVE
The objective of this study was to use high-resolution MDCT to assess the relation of the pulmonary vasculature to septic emboli with particular attention to the feeding vessel sign.


METHODS
The MDCT scans of nine patients with septic emboli were retrospectively, blindly evaluated by two observers. A control group of 10 patients with documented pulmonary metastasis and pathologically proven carcinoma also were included. Transverse images, multiplanar reconstructions, and maximum intensity projections were used to analyze nodules and the pulmonary vasculature. The CT scans were obtained with 1- to 1.25-mm collimation on a 4-, 8-, or 16-MDCT scanner. The feeding vessel sign was defined as a vessel coursing directly into a nodule.


RESULTS
The patients with septic embolism had a total of 141 nodules and 52 wedge-shaped opacities. Transverse images showed that 52 (37%) of the nodules and 11 (22%) of the wedge-shaped opacities had a vessel that appeared to enter the nodule, but multiplanar reconstructions (without IV contrast enhancement) and maximum intensity projections (with IV contrast enhancement) showed the vessels passed around the nodules. Twenty-one (15%) of the spherical nodules and seven (13%) of the wedge-shaped opacities exhibited a central vessel entering the lesion in all imaging planes. All of these vessels were traced to the left atrium on transverse images, a finding consistent with pulmonary vein branches. Similar findings were seen in pulmonary metastatic lesions.


CONCLUSIONS
Although pulmonary septic emboli often appear to have a feeding vessel on conventional cross-sectional images, multiplanar reconstructions show that most of these vessels course around the nodule and that the others are pulmonary veins.
Dodd
Jonathan D
JD
Department of Radiology, Vancouver General Hospital, Vancouver, BC, Canada. jdodd@vanhosp.bc.ca
Souza
Carolina A
CA
Müller
Nestor L
NL
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000382:microbiology; D012189:Retrospective Studies; D018805:Sepsis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods