Image Quality and Radiation Dose of Contrast-Enhanced Chest-CT Acquired on a Clinical Photon-Counting Detector CT vs. Second-Generation Dual-Source CT in an Oncologic Cohort: Preliminary Results

Zielsetzung Our aim was to compare the image quality and patient dose of contrast-enhanced oncologic chest-CT of a first-generation photon-counting detector (PCD-CT) and a second-generation dualsource dual-energy CT (DSCT).

Material und Methoden One hundred oncologic patients (63 male, 65±11 years, BMI: 16–42kg/m2) were prospectively enrolled and evaluated. Clinically indicated contrast-enhanced chest-CT were obtained with PCD-CT and compared to previously obtained chest-DSCT in the same individuals (median time interval: 3 months). PCD-CT was performed in QuantumPlus mode (obtaining full spectral information) at 120kVp. DSCT was performed using 100kV for Tube A and 140kV for Tube B. “T3D” PCD-CT images were evaluated, which emulate conventional 120keV polychromatic images. For DSCT, the convolution algorithm was set at I31f with class 1 iterative reconstruction, and for PCD-CT comparable Br40 kernel and iterative reconstruction strengths (Q1 and Q3). Two radiologists assessed image quality using a five-point Likert scale and performed measurements of vessels and lung parenchyma for signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and for pulmonary metastases tumor-to-lung parenchyma contrast ratio.

Ergebnisse PCD-CT CNRvessel was significantly higher than DSCT CNRvessel (all, p<0.05). Readers rated image contrast of mediastinum, vessels, and lung parenchyma significantly higher in PCD-CT than DSCT images (p<0.001). Q3 PCD-CT CNRlung_parenchyma was significantly higher than DSCT CNRlung_parenchyma and Q1 PCD-CT CNRlung_parenchyma (p<0.01). The tumor-to-lung parenchyma contrast ratio was significantly higher on PCD-CT than DSCT images (0.08±0.04 vs. 0.03±0.02, p<0.001). CTDI, DLP, SSDE mean values for PCD-CT and DSCT were 4.17±1.29mGy vs. 7.21±0.49mGy, 151.01±48.56mGy*cm vs. 288.64±31.17mGy*cm and 4.23±0.97 vs. 7.48±1.09.

Schlussfolgerungen PCD-CT enables oncologic chest-CT with a significantly reduced dose while maintaining image quality similar to a second-generation DSCT for comparable protocol settings.

Publication History

Article published online:
13 April 2023