Impact of spectral body imaging in patients suspected for occult cancer: a prospective study of 503 patients

Abstract

Objectives To investigate the diagnostic impact and performance of spectral dual-layer detector CT in the detection and characterization of cancer compared to conventional CE-CT. Methods In a national workup program for occult cancer, 503 patients (286 females and 217 males) were prospectively enrolled for a contrast-enhanced spectral CT scan. The readings were performed with and without spectral data available. A minimum of 3 months between interpretations was implemented to minimize recall bias. The sequence of reads for the individual patient was randomized. Readers were blinded for patient identifiers and clinical outcome. Two radiologists with 9 and 33 years of experience performed the readings in consensus. If disagreement, a third radiologist with 11 years of experience determined the outcome of the reading Results Significantly more cancer findings were identified on the spectral reading. In 73 cases of proven cancer, we found a sensitivity of 89% vs 77% and a specificity of 77% vs 83% on spectral CT compared to conventional CT. A slight increase in reading time in spectral images of 82 s was found (382 vs 300, p < 0.001). For all cystic lesions, the perceived diagnostic certainty increased from 30% being completely certain to 96% most pronounced in the kidney, liver, thyroid, and ovaries. And adding the spectral information to the reading gave a decrease in follow-up examination for diagnostic certainty (0.25 vs 0.81 per reading, p < 0.001). Conclusion The use of contrast-enhanced spectral CT increases the confidence of the radiologists in correct characterization of various lesions and minimizes the need for supplementary examinations. Key Points • Spectral CT is associated with a higher sensitivity, but a slightly lower specificity compared to conventional CT. • Spectral CT increases the confidence of the radiologists. • The need for supplementary examinations is decreased, with only a slight increase in reading times.

Economic impact of spectral body imaging in diagnosis of patients suspected for occult cancer

“…Caspersen et al reported that the sensitivity of 18 F-FDG PET/CT for cancer detection in patients suspected of serious disease was 81.0%, but with a specificity of only 76.4% [ 22 ]. In a previously published clinical study, the sensitivity of CE-SCT for cancer findings was 89%, with a slightly lower specificity, mainly due to lesions found in the prostate that currently cannot be fully characterized using this technique [ 10 ]. As the patient populations were comparable in both studies (same country, same cancer package, same cancer incidence, same inclusion criteria), CE-SCT seemed to be on par with or even better than 18 F-FDG PET/CT for the diagnosis of malignancy.…”

“…Additional prospective studies following the entire care pathway are needed to assess the underlying economic impact, including time to diagnosis, time to treat, and overall health outcomes, to key stakeholders. The published clinical trial reported that, on average, the radiologist spent additional 82 s reading a CE-SCT compared to a CE-CT [ 10 ]. In both, Denmark and the US, radiologists were currently paid the same amount for both readings.…”

“…The time was stopped when the examination was concluded. Further details regarding the reading of the individual series are presented earlier [ 10 ].…”

“…As the parent study did not collect cost data, we obtained the unit cost from the national data source [ 10 , 17 ]. Direct costs were calculated for each patient for any follow-up procedures suggested for all organ systems.…”

“…A recent study comparing the effectiveness of CE-SCT to contrast-enhanced CT (CE-CT) in a prospectively enrolled patient cohort that entered the NS-CPP found that CE-SCT detected more lesions than CE-CT, but with a slightly lower specificity. However, CE-SCT increased the radiologist’s confidence in the correct characterization of various lesions [ 10 ].…”