Abstract
ObjectivesTo investigate the diagnostic impact and performance of spectral dual-layer detector CT in the detection and characterization of cancer compared to conventional CE-CT.MethodsIn 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 readingResultsSignificantly 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).ConclusionThe 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.
Highlights
Computed tomography (CT) is the leading modality for the detection and characterization of neoplasms [1]
The purpose of this study is to evaluate the impact of contrast-enhanced spectral CT (CE-SCT) compared to contrast-enhanced CT (CE-CT) in a prospectively gathered cohort of patients that enter the occult cancer pathway
Godfrey Hounsfield proposed the concept of using multiple energies in computed tomography to perform material decomposition already in 1973 [26]
Summary
Computed tomography (CT) is the leading modality for the detection and characterization of neoplasms [1]. The fact that perfusion is considered a hallmark of cancer biology [3] makes iodine contrast-enhanced CT a very potent modality for cancer diagnoses. Most techniques create a dual-energy dataset by scanning the same area twice with different kilovolt peak/filtration settings. This can be achieved either by performing two completely separate acquisitions, by rapidly alternating the kilovolt peak during the rotation, or by using two x-ray sources and detectors in one CT scanner. The latest commercial spectral solution uses a dual-layer detector to separate the x-ray spectrum, without the need for changing the tube kilovolt peak or any other scanning parameters. The top row detects low-energy photons while the bottom layer detects high-energy photons [4]
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