Low-keV virtual monoenergetic imaging reconstructions of excretory phase spectral dual-energy CT in patients with urothelial carcinoma: A feasibility study. Issue 116 (July 2019)

• Record Type: Journal Article
• Authors: Zopfs, David; Laukamp, Kai Roman; Pinto dos Santos, Daniel; Sokolowski, Marcel; Große Hokamp, Nils; Maintz, David; Borggrefe, Jan; Persigehl, Thorsten; Lennartz, Simon
• Is Part Of: European journal of radiology. Issue 116(2019)
• Page Start: 135
• Page End: 143
• Publication Date: 2019-07
• Subjects: DECT dual energy CT -- VMI virtual monoenergetic images -- keV kiloelectron volt -- SNR signal-to-noise ratio -- CNR contrast-to-noise ratio; Dual energy CT -- Spectral CT -- Virtual monoenergetic images -- Urothelial carcinoma -- Contrast media -- Excretory phase; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2019.05.003
• Languages: English
• ISSNs: 0720-048X

Abstract

Highlights: CNR of primary tumor vs. surrounding tissue was comparable in excretory phase VMI40keV and venous phase CT. excretory phase VMI40keV yielded superior SNR of vessels and organ parenchyma compared to venous phase CT. Diagnostic certainty and lesion delineation were equal between excretory phase VMI40keV and venous phase CT. VMI40keV effectively antagonize iodine contrast deterioration in excretory phase. Abstract: Objectives: To compare objective and subjective image quality between low keV virtual monoenergetic images (VMI) of the excretory phase and conventional venous phase images derived from spectral dual-energy CT (DECT) in the assessment of urothelial carcinoma. Methods: 26 consecutive patients with histologically confirmed urothelial carcinoma who received clinically indicated venous- and excretory phase abdominal CT scans were included retrospectively. Attenuation, image noise as well as signal- and contrast-to-noise-ratio (SNR, CNR) in venous and excretory phase CT and excretory phase VMI from 40 to 70 keV were obtained from ROI-based measurements in the following regions: urothelial carcinoma, liver, pancreas, renal cortex, subcutaneous fat, renal vein/artery, portal vein, urinary bladder wall, lymph nodes, prostate/uterus. Subjective vessel contrast and delineation of primary tumor manifestations and distant metastases were rated on 5-point Likert scales. Results: In comparison to venous phase CT, attenuation and SNR in excretory phase VMI40keV were higher (p < 0.001), except for liver parenchyma, where they were comparable (p = 0.07 and p = 0.17, respectively). Regarding image noise, no significant difference was found between venous phase CT and excretory phase VMI40keV (p-range: 0.08–1.00), except for liver, portal vein and renal artery, where it was lower in VMI40keV (p < 0.05). CNR of urothelial carcinoma to circumjacent bladder wall was significantly higher in excretory phase VMI40keV compared to venous phase CT. Subjective vessel contrast and delineation of primary tumor and distant metastases received equivalent or higher Likert scores in excretory phase VMI40keV than in venous phase CT. Conclusion: This feasibility study indicates that in the assessment of urothelial carcinoma, virtual monoenergetic excretory phase images at 40 keV acquired with spectral DECT could be feasible to maintain subjective and objective image quality as provided by conventional venous phase images. Still, equivalence with regards to metastatic lesion detection requires further investigation before employing this technique in a potential signal-scan, single-bolus approach.