Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited. US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46]. Variant 4: Presenting to establish care with a past history of a treated PAVM. Follow-up (surveillance) imaging following embolization of PAVM.
Pulmonary Arteriovenous Malformation PAVM . Based on the visualization of contrast material emanating from a particular pulmonary vein, the location of the PAVM in that venous territory can be confirmed [38,40]. In the presence of multiple PAVMs, the usefulness of this imaging modality in identifying the location of the PAVMs is limited. US Echocardiography Transthoracic Resting There is no role for TTE in the resting phase for the evaluation of PAVM. It does allow evaluation of intracardiac shunts and assessment of cardiac function [38]. US Echocardiography Transthoracic With IV Contrast TTCE is an essential diagnostic test for patients suspected of having a PAVM. TTCE with agitated saline has a 98% to 99% sensitivity and a 67% to 91% specificity for detecting PAVMs [41]. The microbubbles are visualized after 3 to 8 cardiac cycles in the left atrium after initial opacification of the right chambers in patients with an intrapulmonary shunt [1]. TTCE does not provide any information regarding the size and location of the PAVM. Based on the appearance of the bubbles in the left atrium a semiquantitative grading system has been developed [42,43]. The grades are defined as 0 with no opacification, grade 1 with <30 bubbles, grade 2 with moderate filling, and grade 3 with complete opacification of the left atrium. The grading system correlates well with the diagnosis of PAVM, with higher grades associated with larger shunts and cerebral complications [41,44,45]. Usefulness of the grading system to predict treatment of PAVM demonstrates that grades 2 and 3 have a positive predictive value of 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively [44]. Adverse events including air embolism are rare with TTCE occurring in <1% [46]. Variant 4: Presenting to establish care with a past history of a treated PAVM. Follow-up (surveillance) imaging following embolization of PAVM.