Related Experiment Videos
Multiple pulmonary arteriovenous fistulas demonstrated by dynamic radionuclide pulmonary perfusion scanning
Abstract:
Dynamic radionuclide perfusion scintigraphy performed with 99mTc-labeled microspheres was instrumental in establishing the diagnosis of multiple, small-vessel, pulmonary arteriovenous fistulas in a 14-month-old patient with cyanosis. Computer analysis of the sequential distribution of tagged microspheres in the pulmonary parenchyma normally demonstrates a curve that rises rapidly to a plateau as the particles microembolize. In the case reported here, the pulmonary flow curve rose rapidly to a maximum and then fell within 2 sec to a plateau of less than 50% of the maximum count, indicating that a large proportion of the microsophers passed through the pulmonary circulation. Conventional pulmonary contrast angiography did not demonstrate any intracardiac shunting but did confirm the presence of multiple pulmonary arteriovenous fistulas.
Insights
Dynamic radionuclide perfusion scintigraphy diagnosed pulmonary arteriovenous fistulas in a cyanotic infant. This imaging technique revealed abnormal microsphere distribution, indicating shunting through multiple fistulas.
Area of Science:
- Nuclear Medicine
- Pediatric Cardiology
- Radiology
Background:
- Pulmonary arteriovenous fistulas (PAVs) are abnormal connections between pulmonary arteries and veins.
- Cyanosis in infants can indicate significant cardiopulmonary disease, including PAVs.
- Accurate diagnosis of PAVs is crucial for appropriate management and improved patient outcomes.
Purpose of the Study:
- To highlight the utility of dynamic radionuclide perfusion scintigraphy in diagnosing multiple, small-vessel pulmonary arteriovenous fistulas.
- To describe the characteristic scintigraphic findings in a pediatric patient with PAVs and cyanosis.
Main Methods:
- Dynamic radionuclide perfusion scintigraphy using 99mTc-labeled microspheres.
- Computer analysis of sequential distribution of microspheres to generate pulmonary flow curves.
- Conventional pulmonary contrast angiography for confirmation.
Main Results:
- Scintigraphy revealed abnormal pulmonary flow curves, rapidly rising to a maximum then falling significantly, indicating microsphere passage through fistulas.
- Computer analysis showed a plateau of less than 50% of maximum counts, suggesting substantial shunting.
- Pulmonary angiography confirmed multiple PAVs but ruled out intracardiac shunting.
Conclusions:
- Dynamic radionuclide perfusion scintigraphy is a valuable tool for diagnosing pulmonary arteriovenous fistulas, especially in complex pediatric cases.
- The characteristic abnormal flow curve on scintigraphy aids in identifying significant intrapulmonary shunting.
- This imaging modality complements conventional angiography in the comprehensive evaluation of PAVs.