The feasibility of reduced contrast flow rates in PE studies
Spotting pulmonary embolism (PE) on computed tomography pulmonary angiography (CTPA) requires a high contrast flow rate to best visualize the pulmonary arteries, but for some patients, this isn’t feasible. New research suggests there may be a way to achieve quality imaging without the high flow rate.
PE protocols are common; around one out of every 1,000 people in the U.S. are diagnosed with a PE every year, but even more undergo imaging to rule out clots.
Given how routine these scans are at some hospitals, it is not uncommon for techs to encounter patients with challenging IV access. Administering a bolus of contrast at a high flow rate, as is required in PE protocols, in these patients could cause their IV to blow.
Authors of a new paper in the Journal of Medical Imaging and Radiation Sciences recently postulated that a lower flow rate could remedy the risk of losing IV access during PE studies.
For their research, the group experimented with two different contrast doses and flow rates in a group of 151 patients who underwent CTPA for suspected PE.
In Singapore, where the study took place, the standard PE protocol consists of a fixed flow rate of 4.5ml/s and 50ml of contrast. Around half of the patients were included in that protocol, while the other half underwent a protocol with up to a 37% and 30% reduction in flow rate and contrast administration.
Two independent radiologists who reviewed the exams did not observe any significant differences in terms of attenuation in any of the seven regions of interest—main pulmonary trunk, right and left pulmonary arteries, right and left lobar arteries and right and left subsegmental arteries—between the protocols. The radiologists’ image quality scores for both protocols were similar as well.
Corresponding author of the paper Wan Chin Lee, a radiographer at Changi General Hospital in Singapore, and co-authors suggest that their findings provide evidence that contrast doses and flow rates can be safely optimized in patients when higher rates present risks.
Learn more about the study here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.