This study aims to compare subjective image quality and diagnostic accuracy of a photon counting detector computed tomography (PCD-CT) scanner compared with an energy integrating detector (EID)-CT scanner as the reference standard.
Computed tomography (CT) imaging plays a key role in diagnostic radiology, and is particularly valuable in assessing a myriad of musculoskeletal conditions (e.g. trauma, degenerative disorders, post-surgical follow-up, inflammatory diseases). The vast majority of today's CT scanners are equipped with an energy-integrating detector (EID), which converts energy of incoming X-ray photons in a two-step process into electric signals: First, scintillators generate visible light, which in turn is converted to the electric signal by photodiodes. Recently, photon-counting detector computed tomography (PCD-CT) scanners became commercially available and have been introduced to improve imaging performance through direct transformation of X-ray photons into electron hole pairs upon absorption in a semiconductor layer, generating an electrical signal proportional to the photon energy. Current literature has shown that PCD-CT can offer higher spatial resolution, increased contrast-to-noise ratio, higher dose-efficiency, and inherent multi-spectral imaging capacity. Moreover, the results from cadaver studies suggest that PCD-CT can preserve image quality with reduced radiation dose. However, data on the diagnostic accuracy of PCD-CT compared to EID-CT is currently limited in the field of musculoskeletal radiology. In addition to conventional CT acquisition, multi-spectral CT imaging in patients with gout and after trauma, is used in clinical routine to delineate materials with a specific absorption coefficient: in gout, urate crystals can be visualized, while after trauma, bone marrow edema can be detected. For EID-CT, different techniques for multi-spectral CT imaging are available (e.g. fast kV switching, dual source CT) which are widely used in clinical routine. Multi-spectral imaging is also inherently available for recently introduced PCD-CT. However, data on diagnostic accuracy of multi-spectral PCD-CT is currently lacking.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
200
Photon counting detector CT scan with dose arbitrarily reduced compared to EID CT scan (e.g., half the dose of EID CT)
Balgrist University Hospital
Zurich, Canton of Zurich, Switzerland
Image Quality PCD CT
Likert scale based - 5 point Likert scale (0 = worst, 5 = best) Visual gradings of PCD-CT image quality. Image quality will be assessed by teams of experienced musculoskeletal radiologists. Images from consistent sets of intra-subject PCD-CT and EID-CT data will be presented to derive the primary outcome data, in particular using visual analog scales (Likert-Scales). Inter-reader reliability will be assessed.
Time frame: 2 years
Diagnostic Accuracy PCD CT
This will involve the calculation of sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy. The EID-CT image interpretation of the attending radiologists, as documented in the written report, will serve as reference standard against which the performance of PCD-CT will be compared. In cases with inconclusive written reports and image findings of EID-CT, a review committee consisting of experienced radiologists (e.g., other attending radiologists, chief of radiology) will be convened, and consensus reading including clinical correlation by consulting with the treating physicians and specialists involved in the patient's care will be done. Diagnostic confidence will be additionally analyzed for PCD-CT scans on a Likert-Scale. Inter-reader reliability will be assessed.
Time frame: 2 years
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