Virtual monoenergetic images preserve diagnostic assessability in contrast media reduced abdominal spectral detector CT

Abstract

<jats:sec><jats:title>Objectives:</jats:title><jats:p> To investigate if low-keV virtual monoenergetic images (VMI<jats:sub>40keV</jats:sub>) from abdominal spectral detector CT (SDCT)with reducedintravenous contrast media (RCM) provide abdominal assessment similar to conventionalimages with standard contrast media dose (SCM). </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> 78 patients with abdominal SDCT were retrospectively included: 41 patients at risk for adverse reactions who received 44 RCM examinations with 50 ml and 37 patients who underwent 44 SCM examinations with 100 ml of contrast media and who were matched for effective body diameters. RCM, SCM images and RCM-VMI<jats:sub>40keV</jats:sub> were reconstructed.Attenuation and signal-to-noise-ratio (SNR) of liver, pancreas, kidneys, lymph nodes, aorta and portal vein were assessed ROI-based. Contrast-to-noise-ratios (CNR) of lymph nodes vs aorta/portal vein were calculated. Two readers assessed organ/vessel contrast,lymph node delineation, image noise and overall assessability using 4-point Likert scales. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> RCMwere inferior to SCM in all quantitative/qualitative criteria. RCM-VMI<jats:sub>40keV</jats:sub> andSCM images showed similar lymph node attenuation (p = 0.83), while for all other ROIs, RCM-VMI<jats:sub>40keV</jats:sub> showed higher attenuation(p ≤ 0.05). SNR was comparable between RCM-VMI<jats:sub>40keV</jats:sub> and SCM images (p-range:0.23–0.99).CNR of lymph nodes was highest in RCM-VMI<jats:sub>40keV</jats:sub> (p ≤ 0.05). RCM-VMI<jats:sub>40keV</jats:sub> received equivalent or higher scores than SCM in all criteria except for organ contrast, overall assessability and image noise, where SCM were superior (p ≤ 0.05). However, RCM-VMI<jats:sub>40keV</jats:sub>received proper or excellent scores in 88.6/94.2/95.4% of the referring cases. </jats:p></jats:sec><jats:sec><jats:title>Conclusions:</jats:title><jats:p> VMI<jats:sub>40keV</jats:sub> counteract contrast deterioration in contrast media reducedabdominal SDCT, facilitating diagnostic assessment. </jats:p></jats:sec><jats:sec><jats:title>Advances in knowledge:</jats:title><jats:p> SDCT-derived VMI<jats:sub>40keV</jats:sub> provide adequate depiction of vessels, organs and lymph nodes even at notable contrast media reduction. </jats:p></jats:sec>

Improvement of image quality of laryngeal squamous cell carcinoma using noise‐optimized virtual monoenergetic image and nonlinear blending image algorithms in dual‐energy computed tomography

“…21 Besides, the iodine contrast increase obtains at low keV levels, resulting from a shift of the energy spectrum towards the physical absorption maximum of iodine, and the 40 keV is more closely approximate the k-edge of iodine (33 keV). 22,23 Therefore, VMI+ algorithm at 40 keV showed the highest CNR and best tumor delineation in laryngeal SCC in our study, which was similar to previous studies regarding liver lesions, peritoneal metastatic deposits, and lung cancer. [24][25][26][27] In the aspect of overall image quality of laryngeal SCC, NBI algorithm showed the best performance.…”

“…VMI+ algorithm uses regional spatial frequency‐based recombination of the high signal at lower energies and the superior noise properties at medium energies to avoid noise increase at lower calculated energies 21 . Besides, the iodine contrast increase obtains at low keV levels, resulting from a shift of the energy spectrum towards the physical absorption maximum of iodine, and the 40 keV is more closely approximate the k‐edge of iodine (33 keV) 22,23 . Therefore, VMI+ algorithm at 40 keV showed the highest CNR and best tumor delineation in laryngeal SCC in our study, which was similar to previous studies regarding liver lesions, peritoneal metastatic deposits, and lung cancer 24–27 .…”

Optimizing Arterial Vessel Contrast in Portal Venous Phase with Virtual Monoenergetic Images from Photon-Counting Detector CT Scans of the Abdomen—First Clinical Experiences

“…When virtually lowering keV values, the attenuation of iodine contrast increases, which has already led to a lower amount of contrast media needed for sufficient contrast in PCD-CT [ 9 , 10 ]. In addition, the extermination of the electronic noise in PCD-CT improves the overall image quality [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ], and PCD scans showed similar or even lower radiation doses compared to energy integrating detector CT scans [ 12 , 19 ].…”

Imaging of the Left Atrial Appendage Before Occluder Device Placement: Evaluation of Virtual Monoenergetic Images in a Single-Bolus Dual-Phase Protocol

“…[17][18][19][20][21] Furthermore, contrast media accounts for additional healthcare expenses. 22,23 Therefore, the reduction of intravenous contrast material has been investigated previously and is also a relevant consideration in patient eligible for occlude device placement 9,24,25 but might cause inadequate opacification of the LAA. By using low-energy virtual monoenergetic images (VMI) closer to the k-edge of iodine, DECT may be helpful in these patients because it enables a contrast boost in the vascular structures.…”

“…By using low-energy virtual monoenergetic images (VMI) closer to the k-edge of iodine, DECT may be helpful in these patients because it enables a contrast boost in the vascular structures. [25][26][27] The purpose of this study was to investigate whether in a single-bolus dual-phase protocol VMI from dual-energy spectral detector CT (SDCT) can be used to enhance contrast and visualization of the LAA in the delayed phase.…”