title: Effect of neck position during radionuclide superior cavography. Its value in the diagnosis of superior vena cava obstruction due to retrosternal goiter.
abstract: In five patients with substernal goiter, three of whom presented with superior vena cava (SVC) syndrome, and in five normal subjects, radionuclide superior cavography (RNSC) was performed with extension and flexion of the neck during tracer administration (simultaneous bilateral injection of Tc-99m pertechnetate). When the tracer was injected during neck extension, venous flow pattern was abnormal in four of five patients, and transit time (TT) prolonged in three of five patients. In this posture, mean TT +/- 1 standard deviation (SD) was 6.3 +/- 2.6 s (range 3.5 to 9 s) for the five patients and 3.5 +/- 0.7 s (range 2.5 to 4.5 s) for a group of five control subjects. When the tracer was injected during neck flexion, all five patients showed abnormal flow patterns and prolonged TT (mean +/- 1 SD 10.1 +/- 4.1 s; range 4.4 to 16 s), in contrast to the control group where a slight decrease in TT was found (mean +/- 1 SD 3 +/- 0.6 s; range 2 to 3.5 s). In the presence of a substernal goiter, or any mobile mass at the thoracic inlet, impairment of venous flow through the SVC system appears to be a common occurrence, readily detectable by RNSC. RNSC should be performed with neck flexion during tracer injection, since in this posture its ability to detect compromised venous flow through the SVC system is enhanced, even in patients without a clinically apparent SVC syndrome.
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006045:Goiter, Substernal / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009333:Neck; D011187:Posture; D011877:Radionuclide Imaging / Q000379:methods*; D014652:Vascular Diseases / Q000209:etiology; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging*