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Pseudoportal Doppler signal in the partially obstructed inferior vena cava
M S Keller1, K J Taylor, C A Riely
1Department of Diagnostic Imaging, Yale University School of Medicine, New Haven, CT 06510.
Insights
The Doppler signal in the inferior vena cava (IVC) can mimic the portal vein, especially in children with partial IVC obstruction. Careful imaging is crucial to differentiate these findings and avoid misdiagnosis.
Area of Science:
- Medical Imaging
- Pediatric Radiology
- Vascular Ultrasound
Background:
- The normal inferior vena cava (IVC) Doppler spectrum exhibits significant flow variability due to cardiac and respiratory influences.
- Distinguishing IVC flow patterns from other vessels is critical in pediatric diagnostic imaging.
Purpose of the Study:
- To investigate the characteristics of Doppler flow patterns in the IVC in pediatric patients.
- To identify potential pitfalls in interpreting IVC Doppler signals, particularly in cases of partial obstruction.
- To differentiate pseudoportal Doppler signals in the IVC from actual portal vein flow.
Main Methods:
- Duplex sonography was performed on 17 subjects, including children post-liver transplantation, those with neuroblastoma, and healthy controls.
- Doppler spectral analysis of the IVC was conducted to assess flow velocity and direction.
- Morphologic imaging was utilized to evaluate the IVC and surrounding structures.
Main Results:
- Six children presented with an IVC Doppler spectrum resembling a unidirectional, low-velocity, continuous-flow pattern typical of the portal vein.
- These cases included children with biliary atresia and cirrhosis, liver transplant recipients, and those with IVC compression by neoplasm.
- Healthy children and adults could exhibit a pseudoportal Doppler signal in the IVC due to subcostal compression.
Conclusions:
- A pseudoportal Doppler signal in the IVC can indicate partial IVC obstruction.
- Awareness of this phenomenon and thorough morphologic assessment are essential to prevent misinterpreting the IVC as a patent portal vein.
- This finding has implications for the accurate diagnosis of vascular abnormalities in pediatric patients.
Abstract:
The Doppler spectrum of the normal inferior vena cava (IVC) shows a majority of flow toward the right atrium, with wide variations in flow velocity and direction owing to effects of the cardiac and respiratory cycles. Seventeen subjects underwent duplex sonography: nine children after liver transplantation, two children with right upper quadrant neuroblastoma, and six healthy control subjects. In six children the spectrum obtained from the IVC bore a strong resemblance to the unidirectional, low-velocity, continuous-flow pattern associated with the portal vein; these children included two children with biliary atresia and cirrhosis, two liver transplant recipients, and two children with IVC compression by neoplasm. In healthy children and adults, a pseudoportal Doppler signal in the IVC can be generated by subcostal right upper quadrant compression. The pseudoportal IVC appears to be a sign of partial IVC obstruction. Knowledge of this potential pitfall and meticulous morphologic imaging can help prevent mistaking the IVC for a patent portal vein.