Photon-counting CT (PCCT) effectively visualizes pulmonary embolism (PE) and reduces radiation dose by 48% compared with traditional CT, according to research presented November 27 at the RSNA meeting.
"[PCCT] ensures confident depiction of acute PE with spectral imaging available at low radiation dose in all patient categories," said presenter Martine Remy-Jardin, MD, PhD, of the University Centre of Lille in France.
Remy-Jardin and colleagues conducted a study that compared performance of traditional CT to PCCT for diagnosing acute PE. The research included a group of patients referred for suspicion of acute pulmonary embolism who underwent a chest CT angiographic (CTA) exam with a traditional CT system (158 patients) and a second group that underwent CTA with a PCCT device (172 patients).
Group 1 patients underwent the exam with one of two scanning options depending on their respiratory status: a dual-energy protocol when a six-second breath hold was possible (Group 1a, 105 individuals), or a high-pitch, single-energy protocol when the patient was short of breath (Group 1b, 53 individuals). All patients in Group 2 were scanned with a multienergy protocol.
| Performance comparison of traditional CT to PCCT for diagnosing acute pulmonary embolism | |||
|---|---|---|---|
| Measure | Group 1 (dual-energy protocol) | Group 2 (multienergy protocol) | Percent reduction |
| Acquisition time | 4 seconds | 0.9 seconds | -77.5% |
| Mean CT dose index-volume (CTDIvol) | 9.5 mGy | 5.1 mGy | -46.3% |
| Median DLP | 323.4 mGy.cm | 169 mGy.cm | -47.7% |
| Proportion of examinations with no cardiogenic motion artifacts | 153 | 30 | -28.6% |
Acute PE was identified in 16 patients in Group 1a (15%), 14 patients in Group 1b (26%), and 21 patients in Group 2 (12%), Remy-Jardin reported. She and her colleagues also found the following:
The study findings confirm the benefit of using PCCT for diagnosing acute PE, Remy-Jardin concluded.
"[Compared with traditional CT, PCCT] maintains high diagnostic value … [and shows] considerable radiation dose reduction of 48%," she said.
![Images show the pectoralis muscles of a healthy male individual who never smoked (age, 66 years; height, 178 cm; body mass index [BMI, calculated as weight in kilograms divided by height in meters squared], 28.4; number of cigarette pack-years, 0; forced expiratory volume in 1 second [FEV1], 97.6% predicted; FEV1: forced vital capacity [FVC] ratio, 0.71; pectoralis muscle area [PMA], 59.4 cm2; pectoralis muscle volume [PMV], 764 cm3) and a male individual with a smoking history and chronic obstructive pulmonary disorder (COPD) (age, 66 years; height, 178 cm; BMI, 27.5; number of cigarette pack-years, 43.2, FEV1, 48% predicted; FEV1:FVC, 0.56; PMA, 35 cm2; PMV, 480.8 cm3) from the Canadian Cohort Obstructive Lung Disease (i.e., CanCOLD) study. The CT image is shown in the axial plane. The PMV is automatically extracted using the developed deep learning model and overlayed onto the lungs for visual clarity.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/03/genkin.25LqljVF0y.jpg?auto=format%2Ccompress&crop=focalpoint&dpr=2&fit=crop&h=167&q=70&w=250)
