The addition of CT to SPECT enables V/Q detection of conditions other than PE (such as radiation therapy induced changes, emphysema, and extrinsic vascular compression from conditions such as neoplasm or mediastinal adenopathy). However, this use remains experimental, and it is not rated as a separate imaging study. CT Chest With IV Contrast There is no relevant literature to support the use of other imaging protocols when CTPA is performed for PE. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA. CT Chest Without and With IV Contrast There is no relevant literature to support CT chest without and with IV contrast for suspected PE, high pretest probability. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA. CT Chest Without IV Contrast There is no relevant literature to support CT chest without IV contrast for suspected PE, high pretest probability. CTA Chest With IV Contrast with CTV Lower Extremities Older literature shows that the field of view for CTA can be extended to include the lower extremities so that both the pulmonary arteries and the deep veins of the leg can be imaged during the same imaging session [25,26]. However, this protocol is very rarely used at present, owing to the accuracy of performing US for DVT and the increased burden of contrast and radiation for the associated extended craniocaudal field of view [27]. Arteriography Pulmonary with Right Heart Catheterization Pulmonary angiography, including right heart catheterization and measurement of pulmonary artery and right heart pressures, is almost never used as a first-line test for PE, although it had historic diagnostic use [17-19] before it was supplanted by CTPA. The overall accuracy of catheter pulmonary angiography is likely to be inferior to CTPA. The role of angiography, when therapy such as pulmonary embolectomy is performed, is not within the scope of this document.
Suspected Pulmonary Embolism PCAs. The addition of CT to SPECT enables V/Q detection of conditions other than PE (such as radiation therapy induced changes, emphysema, and extrinsic vascular compression from conditions such as neoplasm or mediastinal adenopathy). However, this use remains experimental, and it is not rated as a separate imaging study. CT Chest With IV Contrast There is no relevant literature to support the use of other imaging protocols when CTPA is performed for PE. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA. CT Chest Without and With IV Contrast There is no relevant literature to support CT chest without and with IV contrast for suspected PE, high pretest probability. When IV contrast is given during the CT acquisition, the study should be performed as a CTPA. CT Chest Without IV Contrast There is no relevant literature to support CT chest without IV contrast for suspected PE, high pretest probability. CTA Chest With IV Contrast with CTV Lower Extremities Older literature shows that the field of view for CTA can be extended to include the lower extremities so that both the pulmonary arteries and the deep veins of the leg can be imaged during the same imaging session [25,26]. However, this protocol is very rarely used at present, owing to the accuracy of performing US for DVT and the increased burden of contrast and radiation for the associated extended craniocaudal field of view [27]. Arteriography Pulmonary with Right Heart Catheterization Pulmonary angiography, including right heart catheterization and measurement of pulmonary artery and right heart pressures, is almost never used as a first-line test for PE, although it had historic diagnostic use [17-19] before it was supplanted by CTPA. The overall accuracy of catheter pulmonary angiography is likely to be inferior to CTPA. The role of angiography, when therapy such as pulmonary embolectomy is performed, is not within the scope of this document.