Unenhanced Dual-Layer Spectral-Detector CT for Characterizing Indeterminate Adrenal Lesions

Background In abdominal imaging, contrast-enhanced computed tomography (CT) examinations are most commonly applied; however, unenhanced examinations are still needed for several clinical questions but require additional scanning and radiation exposure. Purpose To evaluate accuracy of virtual non-contrast (VNC) from arterial and venous phase spectral-detector CT (SDCT) scans compared to true-unenhanced (TNC) images for the evaluation of liver parenchyma and vessels. Material and Methods A total of 25 patients undergoing triphasic SDCT examinations were included. VNC was reconstructed from arterial and venous phases and compared to TNC images. Quantitative image analysis was performed by region of interest (ROI)-based assessment of mean and SD of attenuation (HU) in each liver segment, spleen, portal vein, common hepatic artery, and abdominal aorta. Subjectively, iodine subtraction and diagnostic assessment were rated on 5-point Likert scales. Results Attenuation and image noise measured in the liver from VNC were not significantly different from TNC (TNC: 54.6 ± 10.8 HU, VNC arterial phase: 55.7 ± 10.8 HU; VNC venous phase: 58.3 ± 10.0 HU; P > 0.05). VNC also showed accurate results regarding attenuation and image noise for spleen, portal vein, and abdominal aorta. Only iodine subtraction in the common hepatic artery in the arterial phase was insufficient which was confirmed by the subjective reading. Apart from that, subjective reading showed accurate iodine subtraction and comparable diagnostic assessment. Conclusion VNC from the arterial and venous phases were very similar to TNC yielding mostly negligible differences in attenuation, image noise, and diagnostic utility. Inadequate iodine subtraction occurred in hepatic arteries in the arterial phase.

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Role of spectral-detector CT in reduction of artifacts from contrast media in axillary and subclavian veins: single institution study in 50 patients

Acta Radiologica ◽

10.1177/0284185119868904 ◽

2019 ◽

Vol 61 (4) ◽

pp. 450-460 ◽

Cited By ~ 3

Author(s):

Kai Roman Laukamp ◽

Amit Gupta ◽

Nils Große Hokamp ◽

Verena Carola Obmann ◽

Frank Philipp Graner ◽

...

Keyword(s):

Soft Tissue ◽

Contrast Media ◽

Intraclass Correlation ◽

Ct Images ◽

Diagnostic Assessment ◽

Surrounding Soft Tissue ◽

Iodinated Contrast ◽

Spectral Detector Ct ◽

Virtual Monoenergetic Images ◽

Monoenergetic Images

Background In CT imaging, a high concentration of iodinated contrast media in axillary and subclavian veins after brachial application can cause perivenous artifacts impairing diagnostic assessment of local vascular structures and soft tissue. Purpose To investigate reduction of perivenous hypo- and hyperattenuating artifacts of the axillary and subclavian veins using virtual monoenergetic images (VMI) in comparison to conventional CT images (CI), acquired on spectral-detector CT. Material and Methods 50 spectral-detector CT datasets of patients with perivenous artifacts from contrast media were included in this retrospective, institutional review board-approved study. CT images and virtual monoenergetic images (range 40–200 keV, 10-keV increments) were reconstructed from the same scans. Quantitative analysis was performed by region of interest-based assessment of mean attenuation (HU) and standard deviation in most pronounced hypo- and hyperdense artifacts and artifact-impaired arteries as well as muscle. Visually, artifact reduction, assessment of vessels, and surrounding soft tissue were rated on 5-point Likert-scales by two radiologists. Results In comparison to CT images, virtual monoenergetic images of ≥90 keV showed a significant reduction of hypo- and hyperattenuating artifacts (hypodense: CI -220.0±171.2 HU; VMI130keV -13.4±49.1 HU; hyperdense: CI 274.6±184.4 HU; VMI130keV 24.2±84.9 HU; P<0.001). Subjective analysis confirmed that virtual-monoenergetic images of ≥100 keV significantly reduced artifacts (hypodense: CI 2[1–3]; VMI130keV 5[4–5], hyperdense: CI 2[1–4]; VMI130keV 5[5–5], P<0.001) and improved diagnostic assessment. Best results for diagnostic assessment were noted for virtual monoenergetic images at 130 keV. Overcorrection of artifacts was observed at higher keV values. Interrater agreement was excellent for each evaluation and keV value (intraclass correlation coefficient 0.89). Conclusion Higher keV virtual monoenergetic images yielded significant reduction of contrast media artifacts and led to improved assessment of vessels and surrounding soft tissue. Recommended keV values for best diagnostic assessment are in the range of 100–160 keV.

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Monoenergetic reconstructions for imaging of coronary artery stents using spectral detector CT: In-vitro experience and comparison to conventional images

Journal of Cardiovascular Computed Tomography ◽

10.1016/j.jcct.2016.12.005 ◽

2017 ◽

Vol 11 (1) ◽

pp. 33-39 ◽

Cited By ~ 38

Author(s):

Tilman Hickethier ◽

Bettina Baeßler ◽

Jan Robert Kroeger ◽

Jonas Doerner ◽

Gregor Pahn ◽

...

Keyword(s):

Coronary Artery ◽

Spectral Detector Ct ◽

Coronary Artery Stents

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The Usefulness of Dual-Layer Spectral Computed Tomography for Myelography: A Case Report and Review of the Literature

Case Reports in Orthopedics ◽

10.1155/2018/1468929 ◽

2018 ◽

Vol 2018 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

Yuji Iyama ◽

Takeshi Nakaura ◽

Ayumi Iyama ◽

Kazuhiro Katahira ◽

Yasuyuki Yamashita

Keyword(s):

Computed Tomography ◽

Spectral Analysis ◽

Spinal Canal ◽

Leg Pain ◽

Monochromatic Imaging ◽

Canal Stenosis ◽

Spectral Computed Tomography ◽

Spectral Detector Ct ◽

Magnetic Resonance Imaging Mri

We describe a case of lumbar stenosis in which retrospective spectral analysis using dual-layer spectral detector computed tomography (CT) had the ability to expand the evaluable region in the spinal canal. Spinal canal stenosis is a common condition whose symptoms (such as lower back and leg pain with walking) deteriorate the quality of life. Generally, magnetic resonance imaging (MRI) and CT myelography are performed to diagnose canal stenosis. Dual-layer spectral detector CT can yield virtual monochromatic imaging and retrospective on-demand spectral analysis without a prescan setting. Spectral analysis could expand the evaluable region in the spinal canal for increasing the contrast enhancement in the canal.

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