title: CT diagnosis of superior vena cava syndrome: importance of collateral vessels.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the importance of collateral vessels in the CT diagnosis of superior vena cava syndrome.
  
  
  METHODS
  Forty-seven patients with CT evidence of obstruction or compression of the superior vena cava or its major tributaries were included in this study. Contrast-enhanced CT scans had been obtained with a combined bolus and drip-infusion technique. We evaluated the CT scans, with particular attention to the presence of collateral vessels (and if present, their location), without knowing the patients' clinical histories. On reviewing the patients' charts, we found 23 patients with signs or symptoms of superior vena cava syndrome. We then correlated the presence of collateral vessels with the presence of signs and symptoms of superior vena cava syndrome. To verify the frequency of visible collateral vessels in healthy subjects, we also evaluated CT scans of 50 control subjects who did not have mediastinal disease or signs and symptoms of superior vena cava syndrome.
  
  
  RESULTS
  Collateral vessels were seen on CT scans in 24 patients. Among the 23 patients who had signs and symptoms of superior vena cava syndrome, 22 patients had CT scans that showed collateral vessels. Two cases were false-positive and one was false-negative. The presence of collateral vessels, regardless of the number and location of the vessels shown on CT scans, was highly accurate as a predictor of superior vena cava syndrome, with a sensitivity of 96% and a specificity of 92%. Collateral vessels were seen in three (6%) of the 50 control subjects.
  
  
  CONCLUSIONS
  We conclude that the presence of collateral vessels is a highly sensitive and specific CT sign of superior vena cava syndrome.
authors.affiliation: Department of Diagnostic Radiology, Gyeongsang National University Hospital, Chinju, Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Kim
authors.forename: H S
authors.initials: HS
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013479:Superior Vena Cava Syndrome / Q000175:diagnosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging