Is your imaging practice paying attention to the acquisition speed of your CT scans? A new study in AJR suggests that CT pulmonary angiography patients are being scanned at an average speed that’s 30% slower than optimal, resulting in unnecessary imaging artifacts.
CT is radiology’s workhorse modality, but recent studies have found wide variation in CT scanning parameters, sometimes between scanners in the same health system or even the same facility.
- This can result in patients getting different levels of radiation dose for the same type of study, or differences in image quality that can make image comparisons more difficult.
To even out the variation, imaging groups have proposed best-practice scanning protocols for different exams and anatomical regions.
- Most of these protocols focus on reducing radiation dose, but there are other elements – such as scan acquisition speed – that are also important.
For CT pulmonary angiography exams, scans that are performed too slowly run the risk of motion artifacts caused by patients breathing.
- Imaging sites, therefore, should try to optimize scan speed, which is determined by a mix of collimation, pitch, and gantry rotation time.
Researchers in the new study — from UC San Francisco and University of Wisconsin — found that many sites were using a fixed scan speed for CTPA regardless of patient characteristics.
- They analyzed data for 167k CTPA scans acquired from 2016 to 2021, with data coming from 121 sites using 28 different scanner models from various manufacturers.
Researchers compared scan speeds to best-practice levels, revealing …
- Scans on average were 30% slower than the best-practice speed.
- 87% of acquisitions were slower.
- 62% were more than 20% slower.
- Scan speeds varied widely by vendor and by scanner model.
Researchers concluded that CT sites weren’t optimizing their equipment and not implementing the fastest scan speeds available.
- As a result, they could be generating widespread motion artifacts, especially for smaller patients.
The Takeaway
The new findings show that radiation dose isn’t the only CT scanning parameter that needs optimization. Imaging practices should take a look at their CT protocols to ensure they have the optimal settings, especially for CTPA scans of smaller patients.
