Journal of clinical ultrasound : JCU
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A common finding on abdominal ultrasound and CT examinations is variation in the size of the inferior vena cava (IVC). On occasion the infrahepatic IVC even assumes a slit-like appearance. Though commonly related to respiratory change and to the degrees of intra-abdominal pressure, some have claimed the slit-IVC may be an indicator of hypovolemia. ⋯ The subhepatic IVC decreased in size at end-expiration (A-P 1.2 cm) and frequently collapsed with the Valsalva maneuver (A-P 0.7 cm). Dramatic changes in the size of the IVC with changes in ventilation are normal variants. The use of the slit-IVC to diagnose hypovolemia should be done with caution.