CT scans for lung blood clots in sickle cell increased after 2020
Increase raises concerns about radiation exposure, cancer risk
The use of computed tomography pulmonary angiography (CTPA) to assess the presence of blood clots in lung blood vessels increased significantly in people with sickle cell disease (SCD) after 2020, a study in Bahrain shows.
The study indicates that a third of patients underwent several scans, many of which occurred within a six-month to year interval, raising concerns about cumulative radiation exposure and its associated increased cancer risk. CTPA is an imaging technique that uses X-rays and a contrast dye to look for blood clots in the lungs.
“Addressing this issue requires a comprehensive approach, including the implementation of low-dose CTPA protocols and the consideration of alternative imaging methods to reduce radiation risk,” the study’s researchers wrote. The study, “Trends in CT pulmonary angiography utilization and recurrent imaging in sickle cell disease: a longitudinal study,” was published in the International Journal of Emergency Medicine.
SCD is caused by the production of a faulty version of hemoglobin, the protein that carries oxygen in red blood cells, causing them to acquire a sickle-like shape. Sickled cells are more easily destroyed and are prone to stick to each other, blocking blood flow, and leading to a wide array of symptoms and complications.
Complications stemming from blood vessel blockage include painful vaso-occlusive crises and acute chest syndrome, resembling a pulmonary embolism, which is when a blood clot gets lodged and blocks blood flow in lung blood vessels.
Increase in CT scans
However, “research examining the use of computed tomography pulmonary angiography (CTPA) in patients with SCD remains limited,” the researchers wrote.
To investigate the use of CTPA in people with SCD in Bahrain, researchers retrospectively studied 1,084 patients who had at least one scan in an emergency setting for suspected pulmonary embolism between April 2013 and April 2024. Most were men (56%) and had their first scan at a median age of 35. A total of 1,934 scans were performed, corresponding to a mean of 1.8 per patient.
From 2014 to 2020, the average number of CT scans per month remained stable, varying between 10 to 13.6 per month, but it increased rapidly after 2020, reaching a peak in 2023, with 31.3 scans a month. This rise coincided with the COVID-19 pandemic. Accordingly, the number of detected cases of pulmonary embolism increased from an average of 1.6 a month from 2014-2019 to 2.6 a month from 2020-2023.
More than a third of the patients (38.3%) had more than one scan during the study period. The median interval between successive scans was about a year (12.6 months), but a third (32.5%) were carried out within six months. Among patients with multiple scans, 50% had two scans, 26% had three scans, and 24% had four or more.
A pulmonary embolism was detected in 172 patients (15.9%) who had 189 scans. The positivity rate of pulmonary embolism was lower in recurrent than in initial scans, but the difference wasn’t statistically significant (8.8% vs. 10.5%).
“This study highlights a significant shift in CTPA utilization patterns among patients with SCD, particularly following the COVID-19 pandemic,” the researchers wrote. “Further research is crucial to uncover the factors driving this surge in CTPA use and to develop diagnostic strategies that optimize both accuracy and patient safety.”
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