Dual-Energy Low-keV or Single-Energy Low-kV CT for Endoleak Detection?

Skawran, Stephan; Angst, Florian; Blüthgen, Christian; Eberhard, Matthias; Kälin, Pascal; Kobe, Adrian; Nagy, Daniel; Szücs-Farkas, Zsolt; Alkadhi, Hatem; Euler, André

doi:10.1097/rli.0000000000000606

Cited by 17 publications

(14 citation statements)

References 35 publications

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“…Our results for objective image quality are comparable to a previous phantom study comparing advanced VMIs (VMI+) of dual-energy EID-CT to single-energy low-kV imaging EID-CT on a third-generation dual-source CT system. 35 Here, CNR was significantly higher for VMI at 40 and 50 keVas compared with single-energy at 80 kV. As a difference to this study, in which subjective image quality was significantly lower for VMI, we did not find a significant difference in subjective overall image quality among 40 keV, 45 keV, and EID-CT.…”

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confidence: 85%

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High-Pitch Photon-Counting Detector Computed Tomography Angiography of the Aorta

et al. 2021

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PurposeThe aims of this study were to determine the objective and subjective image quality of high-pitch computed tomography (CT) angiography of the aorta in clinical dual-source photon-counting detector CT (PCD-CT) and to compare the image quality to conventional dual-source energy-integrating detector CT (EID-CT) in the same patients at equal radiation dose.Materials and MethodsPatients with prior CT angiography of the thoracoabdominal aorta acquired on third-generation dual-source EID-CT in the high-pitch mode and with automatic tube voltage selection (ATVS, reference tube voltage 100 kV) were included. Follow-up imaging was performed on a first-generation, clinical dual-source PCD-CT scanner in the high-pitch and multienergy (QuantumPlus) mode at 120 kV using the same contrast media protocol as with EID-CT. Radiation doses between scans were matched by adapting the tube current of PCD-CT. Polychromatic images for both EID-CT and PCD-CT (called T3D) and virtual monoenergetic images at 40, 45, 50, and 55 keV for PCD-CT were reconstructed. Computed tomography attenuation was measured in the aorta; noise was defined as the standard deviation of attenuation; contrast-to-noise ratio (CNR) was calculated. Subjective image quality (noise, vessel attenuation, vessel sharpness, and overall quality) was rated by 2 blinded, independent radiologists.ResultsForty patients were included (mean age, 63 years; 8 women; mean body mass index [BMI], 26 kg/m2). There was no significant difference in BMI, effective diameter, or radiation dose between scans (all P's > 0.05). The ATVS in EID-CT selected 70, 80, 90, 100, 110, and 120 kV in 2, 14, 14, 7, 2, and 1 patients, respectively. Mean CNR was 17 ± 8 for EID-CT and 22 ± 7, 20 ± 6, 18 ± 5, 16 ± 5, and 12 ± 4 for PCD-CT at 40, 45, 50, 55 keV, and T3D, respectively. Contrast-to-noise ratio was significantly higher for 40 and 45 keV of PCD-CT as compared with EID-CT (both P's < 0.05). The linear regression model (adjusted R2, 0.38; P < 0.001) revealed that PCD-CT reconstruction (P < 0.001), BMI group (P = 0.007), and kV of the EID-CT scan (P = 0.01) were significantly associated with CNR difference, with an increase by 34% with PCD-CT for overweight as compared with normal weight patients. Subjective image quality reading revealed slight differences between readers for subjective vessel attenuation and sharpness, whereas subjective noise was rated significantly higher for 40 and 45 keV (P < 0.001) and overall quality similar (P > 0.05) between scans.ConclusionsHigh-pitch PCD-CT angiography of the aorta with VMI at 40 and 45 keV resulted in significantly increased CNR compared with EID-CT with ATVS at matched radiation dose. The CNR gain of PCD-CT increased in overweight patients. Taking into account the subjective analysis, VMI at 45 to 50 keV is proposed as the best trade-off between objective and subjective image quality.

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confidence: 82%

High-Pitch Photon-Counting Detector Computed Tomography Angiography of the Aorta

et al. 2021

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“…The CTA at low tube voltages (low-kV imaging) has been investigated as a tool to increase CT attenuation and the contrast-to-noise ratio (CNR) of the aorta with the option of radiation dose and/or CM reduction 18–30 . Following these lines, automatic tube voltage selection (ATVS) has been introduced as a means to reduce radiation dose in CT depending on the imaging task and patient habitus, while maintaining image quality in terms of the CNR 31 .…”

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“…17 The CTA at low tube voltages (low-kV imaging) has been investigated as a tool to increase CT attenuation and the contrast-to-noise ratio (CNR) of the aorta with the option of radiation dose and/or CM reduction. [18][19][20][21][22][23][24][25][26][27][28][29][30] Following these lines, automatic tube voltage selection (ATVS) has been introduced as a means to reduce radiation dose in CT depending on the imaging task and patient habitus, while maintaining image quality in terms of the CNR. 31 The ATVS system has primarily been designed for radiation dose optimization by selecting the tube voltage level that offers lowest radiation dose at maintained CNR.…”

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Computed Tomography Angiography of the Aorta—Optimization of Automatic Tube Voltage Selection Settings to Reduce Radiation Dose or Contrast Medium in a Prospective Randomized Trial

et al. 2020

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Objectives: The aim of this study was to compare the image quality of low-kV protocols with optimized automatic tube voltage selection (ATVS) settings to reduce either radiation dose or contrast medium (CM) with that of a reference protocol for computed tomography angiography (CTA) of the thoracoabdominal aorta. Materials and Methods: In this institutional review board-approved, singlecenter, prospective randomized controlled trial, 126 patients receiving CTA of the aorta were allocated to one of three computed tomography protocols: (A) reference protocol at 120 kVp and standard weight-adapted CM dose; (B) protocol at 90 kVp, reduced radiation and standard CM dose; and (C) protocol at 90 kVp, standard radiation and reduced CM dose. All three protocols were performed on a third-generation dual-source computed tomography scanner using the semimode of the ATVS system. The image-task-dependent optimization settings of the ATVS (slider level) were adjusted to level 11 (high-contrast task) for protocols A and B and level 3 (low-contrast task) for protocol C. Radiation dose parameters were assessed. The contrast-to-noise ratios (CNRs) of protocols B and C were tested for noninferiority compared with A. Subjective image quality was assessed using a 5-point Likert scale. Results: Size-specific dose estimate was 34.3% lower for protocol B compared with A (P < 0.0001). Contrast medium was 20.2% lower for protocol C compared with A (P < 0.0001). Mean CNR in B and C was noninferior to protocol A (CNR of 30.2 ± 7, 33.4 ± 6.7, and 30.5 ± 8.9 for protocols A, B, and C, respectively). There was no significant difference in overall subjective image quality among protocols (4.09 ± 0.21, 4.03 ± 0.19, and 4.08 ± 0.17 for protocols A, B, and C, respectively; P = 0.4). Conclusions: The slider settings of an ATVS system can be adjusted to optimize either radiation dose or CM at noninferior image quality in low-kV CTA of the aorta. This optimization could be used to extend future ATVS algorithms to take clinical risk factors like kidney function of individual patients into account.

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“…Endoleaks are associated with an increased aneurysm rupture rate and a reduced viability and patency of the endograft itself 4 . Therefore, in patients treated with EVAR, life-long follow-up imaging, usually with multiphasic computed tomography (CT) angiography, is necessary 5,6 . The typical CT protocol consists of a true noncontrast (TNC) phase, an arterial phase, and a venous phase 5 .…”

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Photon-Counting Detector CT Angiography for Endoleak Detection After Endovascular Aortic Repair

Turrion Gomollon,

Mergen,

Sartoretti

et al. 2023

Invest Radiol

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Objectives The aim of this study was to compare image quality and endoleak detection after endovascular abdominal aortic aneurysm repair between a triphasic computed tomography (CT) with true noncontrast (TNC) and a biphasic CT with virtual noniodine (VNI) images on photon-counting detector CT (PCD-CT). Materials and Methods Adult patients after endovascular abdominal aortic aneurysm repair who received a triphasic examination (TNC, arterial, venous phase) on a PCD-CT between August 2021 and July 2022 were retrospectively included. Endoleak detection was evaluated by 2 blinded radiologists on 2 different readout sets (triphasic CT with TNC-arterial-venous vs biphasic CT with VNI-arterial-venous). Virtual noniodine images were reconstructed from the venous phase. The radiologic report with additional confirmation by an expert reader served as reference standard for endoleak presence. Sensitivity, specificity, and interreader agreement (Krippendorf α) were calculated. Image noise was assessed subjectively in patients using a 5-point scale and objectively calculating the noise power spectrum in a phantom. Results One hundred ten patients (7 women; age, 76 ± 8 years) with 41 endoleaks were included. Endoleak detection was comparable between both readout sets with a sensitivity and specificity of 0.95/0.84 (TNC) versus 0.95/0.86 (VNI) for reader 1 and 0.88/0.98 (TNC) versus 0.88/0.94 (VNI) for reader 2. Interreader agreement for endoleak detection was substantial (TNC: 0.716, VNI: 0.756). Subjective image noise was comparable between TNC and VNI (4; IQR [4, 5] vs 4; IQR [4, 5], P = 0.44). In the phantom, noise power spectrum peak spatial frequency was similar between TNC and VNI (both fpeak = 0.16 mm−1). Objective image noise was higher in TNC (12.7 HU) as compared with VNI (11.5 HU). Conclusions Endoleak detection and image quality were comparable using VNI images in biphasic CT as compared with TNC images in triphasic CT offering the possibility to reduce scan phases and radiation exposure.

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Dual-Energy Low-keV or Single-Energy Low-kV CT for Endoleak Detection?

Cited by 17 publications

References 35 publications

High-Pitch Photon-Counting Detector Computed Tomography Angiography of the Aorta

High-Pitch Photon-Counting Detector Computed Tomography Angiography of the Aorta

Computed Tomography Angiography of the Aorta—Optimization of Automatic Tube Voltage Selection Settings to Reduce Radiation Dose or Contrast Medium in a Prospective Randomized Trial

Photon-Counting Detector CT Angiography for Endoleak Detection After Endovascular Aortic Repair

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