From the Guidelines
For a drive line evaluation, a CT scan with contrast is recommended, specifically a chest and abdominal CT with intravenous contrast to visualize the drive line path, surrounding tissues, and potential complications, as suggested by the most recent guidelines 1. This typically involves thin-slice imaging (1-2mm) for detailed assessment, and the scan should include the entire course of the drive line from the implanted device to the exit site on the skin. Prior to the scan, the external components of the drive line should be secured and protected, though they generally don't need to be disconnected during imaging. The radiologist should be informed about the specific purpose of evaluating the drive line to ensure proper protocol selection and focus on relevant areas. Some key considerations for the CT scan protocol include:
- Using a multislice CT scanner with collimation of 0.6 mm and individual tube voltage and tube current time product determined by automatic dose modulation, as recommended in recent guidelines 1.
- Reconstruction slice thickness should be between 0.5 and 1.0 mm.
- Patient and CT technology adapted injection of 50–100 mL of non-ionic iodinated contrast agent (≥350 mg/mL) using a power injector (≥4 mL/s).
- Arterial phase: bolus-tracking method (threshold of 100 HU); ECG triggering.
- Venous phase: 50 s after finishing the arterial phase acquisition. This imaging is valuable for detecting complications such as infection, hematoma, seroma, or drive line displacement, which may present with symptoms like pain, drainage, or erythema along the drive line tract. CT is preferred over MRI due to potential compatibility issues between MRI and implanted cardiac devices, although CT scans are safe to use in patients with a CIED, and can be helpful to assess LVAD driveline infection and larger abscesses around the LVAD components 1.
From the Research
CT Scan for Drive Line Evaluation
- The type of CT scan for a drive line evaluation is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, the studies discuss the use of contrast-enhanced CT scans for various evaluations, including vascular and visceral examinations 2.
- The choice of contrast agent and protocol depends on the specific examination and patient factors, such as weight and cardiac output 2.
- Some studies suggest the use of low-concentration iodinated contrast agents and low tube voltage to reduce radiation dose while maintaining image quality 3, 5, 6.
- The image quality and radiation dose of contrast-enhanced CT scans can be affected by various factors, including the type of reconstruction algorithm used 5, 6.
- Deep learning reconstruction algorithms have been shown to improve image quality and reduce radiation dose in some studies 5.
- Photon-counting detector CT has also been shown to provide high image quality with reduced radiation dose compared to dual-source CT 6.