Abdominal vessel depiction on virtual triphasic spectral detector CT: initial clinical experience

Abstract Purpose To evaluate vessel assessment in virtual monoenergetic images (VMI40keV) and virtual-non-contrast images (VNC) derived from venous phase spectral detector computed tomography (SDCT) acquisitions in comparison to arterial phase and true non-contrast (TNC) images. Methods Triphasic abdominal SDCT was performed in 25 patients including TNC, arterial and venous phase. VMI40keV and VNC were reconstructed from the venous phase and compared to conventional arterial-phase images (CIart), TNC and conventional venous-phase images (CIven). Vessel contrast and virtual contrast removal were analyzed with region-of-interest-based measurements and in a qualitative assessment. Results Quantitative analysis revealed no significant attenuation differences between TNC and VNC in arterial vessels (p-range 0.07–0.47) except for the renal artery (p = 0.011). For venous vessels, significant differences between TNC and VNC were found for all veins (p < 0.001) except the inferior vena cava (p = 0.26), yet these differences remained within a 10 HU range in most patients. No significant attenuation differences were found between CIart/VMI40keV in arterial vessels (p-range 0.06–0.86). Contrast-to-noise ratio provided by VMI40keV and CIart was equivalent for all arterial vessels assessed (p-range 0.14–0.91). Qualitatively, VMI40keV showed similar enhancement of abdominal and pelvic arteries as CIart and VNC were rated comparable to TNC. Conclusion Our study suggests that VNC and VMI40keV derived from single venous-phase SDCT offer comparable assessment of major abdominal vessels as provided by routine triphasic examinations, if no dynamic contrast information is required.

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Virtual non-contrast for evaluation of liver parenchyma and vessels: results from 25 patients using multi-phase spectral-detector CT

Acta Radiologica ◽

10.1177/0284185119893094 ◽

2019 ◽

Vol 61 (8) ◽

pp. 1143-1152 ◽

Cited By ~ 3

Author(s):

Kai Roman Laukamp ◽

Vivian Ho ◽

Verena Carola Obmann ◽

Karin Herrmann ◽

Amit Gupta ◽

...

Keyword(s):

Portal Vein ◽

Hepatic Artery ◽

Abdominal Aorta ◽

Liver Parenchyma ◽

Image Noise ◽

Common Hepatic Artery ◽

Diagnostic Assessment ◽

Arterial Phase ◽

Spectral Detector Ct ◽

Venous Phase

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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Phantomless assessment of volumetric bone mineral density using virtual non-contrast images from spectral detector computed tomography

British Journal of Radiology ◽

10.1259/bjr.20190992 ◽

2020 ◽

Vol 93 (1109) ◽

pp. 20190992 ◽

Cited By ~ 2

Author(s):

David Zopfs ◽

Simon Lennartz ◽

Charlotte Zaeske ◽

Martin Merkt ◽

Kai Roman Laukamp ◽

...

Keyword(s):

Computed Tomography ◽

Bone Mineral Density ◽

Contrast Enhancement ◽

Bone Mineral ◽

Lumbar Vertebrae ◽

Volumetric Bone Mineral Density ◽

Mineral Density ◽

Phase Images ◽

Spectral Detector Ct ◽

Venous Phase

Objective: To evaluate phantomless assessment of volumetric bone mineral density (vBMD) based on virtual non-contrast images of arterial (VNCa) and venous phase (VNCv) derived from spectral detector CT in comparison to true non-contrast (TNC) images and adjusted venous phase conventional images (CIV(adjusted)). Methods: 104 consecutive patients who underwent triphasic spectral detector CT between January 2018 and April 2019 were retrospectively included. TNC, VNCa, VNCv and venous phase images (CIV) were reconstructed. vBMD was obtained by two radiologists using an FDA/CE-cleared software. Average vBMD of the first three lumbar vertebrae was determined in each reconstruction; vBMD of CIV was adjusted for contrast enhancement as suggested earlier. Results: vBMD values obtained from CIV(adjusted) are comparable to vBMD values derived from TNC images (91.79 ± 36.52 vs 90.16 ± 41.71 mg/cm3, p = 1.00); however, vBMD values derived from VNCa and VNCv (42.20 ± 22.50 and 41.98 ± 23.3 mg/cm3 respectively) were significantly lower as compared to vBMD values from TNC and CIV(adjusted) (all p ≤ 0.01). Conclusion: Spectral detector CT-derived virtual non-contrast images systematically underestimate vBMD and therefore should not be used without appropriate adjustments. Adjusted venous phase images provide reliable results and may be utilized for an opportunistic BMD screening in CT examinations. Advances in knowledge: Adjustments of venous phase images facilitate opportunistic assessment of vBMD, while spectral detector CT-derived VNC images systematically underestimate vBMD.

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Radiomic texture analysis correlates with PDAC patient outcomes on SM-88.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.e16776 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. e16776-e16776

Author(s):

Allyson J. Ocean ◽

Ronald Lee Korn ◽

Semmie Kim ◽

Andre Burkett ◽

Ziad Hindosh ◽

...

Keyword(s):

Region Of Interest ◽

Tumor Diameter ◽

Portal Venous Phase ◽

Prior Therapy ◽

Coarse Texture ◽

Size Number ◽

Phase Images ◽

Venous Phase ◽

Textural Changes ◽

Ecog Ps

e16776 Background: SM-88 (racemetyrosine) is a dysfunctional tyrosine derivative; previous studies demonstrated a well-tolerated profile with encouraging efficacy. Recent advances in image analysis using Quantitative Textural Analysis (QTA) have uncovered non-invasive biomarkers that correlate with molecular drivers of cancer and prognostic signatures of response in PDAC. Earlier radiomic data from subjects treated with SM-88 showed a positive correlation between circulating tumor cells and tumor texture at baseline. This study extends those findings to focus on radiomic changes associated with SM-88 doses in a Phase II dose escalation trial (NCT03512756). Methods: Retrospective evaluation of 18 subjects with >1 prior therapy, ECOG PS <2, with no restriction on size, number, or locations of mets, and had baseline (BL) and follow up (FUP) contrast enhanced CTs. Subjects received > 1 cycle of SM-88 at either 460mg (n = 8) or 920mg (n = 10) QD oral doses. CTs were analyzed by the QTA platform (TexRad, Essex, UK) for tumor texture. The largest met of each subject was selected using portal venous phase images. A region of interest was posited on the axial slice with the longest tumor diameter and features automatically generated using voxel resampling to correct for scanner variability across subjects and time points. Results were displayed as histogram frequency curves (HFCs) of pixel densities (Hounsfield Units). First order HFC analysis (mean, StDev, MPP, skewness, kurtosis) at spatial scale filters (SSF) ranging from no filter, to fine, to coarse texture (SSF:0, SSF:2, SSF:6, respectively) were reported. Results: Subjects whose largest lesions showed greater changes in tumor texture at FUP vs. BL were more likely to develop tumor progression (StDev in PD (n = 10) vs SD (n = 7) (1 N/A): -0.07 vs -0.25, p = 0.05). Greater tumor textural changes were associated with poor survival at 180 days (Skewness: Chi-Sq. = 4.81, p = 0.03; HR = 4.1 for above median □Skewssf3). There was a negative change in FUP kurtosis vs BL in the 6 subjects who developed new lesions vs the 12 who did not (mean □kurtosis = -0.67 vs +2.63, p = 0.05). Greater change in tumor texture on FUP vs BL scans was seen in the 460mg vs 920mg group (MPPLD = -0.29, MPPHD = -0.04; p = 0.05) suggesting more tumor stability (less change in texture and better outcomes) was associated with the 920mg dose. Conclusions: Tumor lesions in subjects on 920mg of SM-88 were less likely to show a change in tumor texture and were associated with better outcomes. Using radiomic QTA, less tumor texture variability from baseline may be associated with better outcomes in PDAC subjects.

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Evaluation of the liver with virtual non-contrast: single institution study in 149 patients undergoing TAVR planning

British Journal of Radiology ◽

10.1259/bjr.20190701 ◽

2020 ◽

Vol 93 (1106) ◽

pp. 20190701 ◽

Cited By ~ 1

Author(s):

Kai Roman Laukamp ◽

Simon Lennartz ◽

Vivian Ho ◽

Nils Große Hokamp ◽

David Zopfs ◽

...

Keyword(s):

Contrast Media ◽

Abdominal Aorta ◽

Region Of Interest ◽

Hounsfield Unit ◽

Liver Parenchyma ◽

Arterial Phase ◽

Single Institution ◽

Transcatheter Aortic Valve ◽

Spectral Detector Ct ◽

Early Arterial Phase

Objective: To evaluate accuracy of virtual-non-contrast images (VNC) compared to true-unenhanced-images (TNC) for evaluation of liver attenuation acquired using spectral-detector CT (SDCT). Methods: 149 patients who underwent multiphase transcatheter-aortic-valve-replacement (TAVR) SDCT-examinations [unenhanced-chest (TNC), CT-angiography chest (CTA-chest, early arterial-phase) and abdomen (CTA-abdomen, additional early arterial-phase after a second injection of contrast media)] were retrospectively included. VNC of CTA-chest (VNC-chest) and CTA-abdomen (VNC-abdomen) were reconstructed and compared to TNC. Region of interest-based measurement of mean attenuation (Hounsfield unit, HU) was applied in the following regions: liver, spleen, abdominal aorta and paraspinal muscle. Results: VNC accuracy was high in the liver, spleen, abdominal aorta and muscle for abdomen-scanning. For the liver, average attenuation was 59.0 ± 9.1 HU for TNC and 72.6 ± 9.5 HU for CTA-abdomen. Liver attenuation in VNC-abdomen (59.1 ± 6.4 HU) was not significantly different from attenuation in TNC (p > 0.05). In contrast, VNC was less accurate for chest-scanning: Due to the protocol, in CTA-chest no contrast media was present in the liver parenchyma as indicated by the same attenuation in TNC (59.0 ± 9.1 HU) and CTA-chest (58.8 ± 8.9 HU, p > 0.05). Liver attenuation in VNC-chest (56.2 ± 6.4 HU, p < 0.05) was, however, significantly lower than in TNC and CTA-chest implying an artificial reduction of attenuation. Conclusion: VNC performed well in a large cohort of TAVR-examinations yielding equivalent mean attenuations to TNC; however, application of this technique might be limited when no or very little contrast media is present in parenchyma, more precisely in an early arterial-phase of the liver. Advances in knowledge: This study showed that VNC can be reliably applied in cardiac protocols when certain limitations are considered

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Assessment of Solitary Pulmonary Nodules Based on Virtual Monochrome Images and Iodine-Dependent Images Using a Single-Source Dual-Energy CT with Fast kVp Switching

Journal of Clinical Medicine ◽

10.3390/jcm9082514 ◽

2020 ◽

Vol 9 (8) ◽

pp. 2514

Author(s):

Arkadiusz Zegadło ◽

Magdalena Żabicka ◽

Marta Kania-Pudło ◽

Artur Maliborski ◽

Aleksandra Różyk ◽

...

Keyword(s):

Lung Nodule ◽

Pulmonary Nodules ◽

Iodine Concentration ◽

Modern Medicine ◽

Dual Energy ◽

Arterial Phase ◽

Dual Energy Ct ◽

Solitary Pulmonary Nodules ◽

Phase Images ◽

Venous Phase

With lung cancer being the most common malignancy diagnosed worldwide, lung nodule assessment has proved to be one of big challenges of modern medicine. The aim of this study was to examine the usefulness of Dual Energy Computed Tomography (DECT) in solitary pulmonary nodule (SPN) assessment. Between January 2017 and June 2018; 65 patients (42 males and 23 females) underwent DECT scans in the late arterial phase (AP) and venous phase (VP). We concluded that imaging at an energy level of 65 keV was the most accurate in detecting malignancy in solitary pulmonary nodules (SPNs) measuring ≤30 mm in diameter on virtual monochromatic maps. Both virtual monochromatic images and iodine concentration maps prove to be highly useful in differentiating benign and malignant pulmonary nodules. As for iodine concentration maps, the analysis of venous phase images resulted in the highest clinical usefulness. To summarize, DECT may be a useful tool in the differentiation of benign and malignant SPNs. A single-phase DECT examination with scans acquired 90 s after contrast media injection is recommended.

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Case 17.17

Mayo Clinic Body MRI Case Review ◽

10.1093/med/9780199915705.003.0435 ◽

2014 ◽

pp. 821-822

Author(s):

Christine U. Lee ◽

James F. Glockner

Keyword(s):

Arterial Phase ◽

Portal Venous Phase ◽

Phase Images ◽

Signal Void ◽

Venous Phase

58-year-old woman with cirrhosis Axial precontrast (Figure 17.17.1) and arterial phase (Figure 17.17.2) and portal venous phase (Figure 17.17.3) postgadolinium water and fat images from a 3D SPGR Dixon acquisition. Notice that the phase and frequency directions have been swapped on the arterial phase acquisition and that there is a large geographic signal void in the middle of the liver on the water image, with the missing anatomy appearing on the corresponding fat image. All artifacts have been corrected on the portal venous phase images....

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The utility of a dual-phase, dual-energy CT protocol in patients presenting with overt gastrointestinal bleeding

Acta Radiologica Open ◽

10.1177/20584601211030658 ◽

2021 ◽

Vol 10 (7) ◽

pp. 205846012110306

Author(s):

Payam Mohammadinejad ◽

Lukasz Kwapisz ◽

Jeff L Fidler ◽

Shannon P Sheedy ◽

Jay P Heiken ◽

...

Keyword(s):

Dual Energy ◽

Arterial Phase ◽

Gi Bleeding ◽

Two Phase ◽

Portal Venous Phase ◽

Portal Phase ◽

Ct Protocol ◽

Phase Images ◽

Venous Phase ◽

Gi Bleed

Background Due to their easy accessibility, CT scans have been increasingly used for investigation of gastrointestinal (GI) bleeding. Purpose To estimate the performance of a dual-phase, dual-energy (DE) GI bleed CT protocol in patients with overt GI bleeding in clinical practice and examine the added value of portal phase and DE images. Materials and Methods Consecutive patients with GI bleeding underwent a two-phase DE GI bleed CT protocol. Two gastroenterologists established the reference standard. Performance was estimated using clinical CT reports. Three GI radiologists rated confidence in GI bleeding in a subset of 62 examinations, evaluating first mixed kV arterial images, then after examining additional portal venous phase images, and finally after additional DE images (virtual non-contrast and virtual monoenergetic 50 keV images). Results 52 of 176 patients (29.5%) had GI bleeding by the reference standard. The overall sensitivity, specificity, and positive and negative predictive values of the CT GI bleed protocol for detecting GI bleeding were 65.4%, 89.5%, 72.3%, and 86.0%, respectively. In patients with GI bleeding, diagnostic confidence of readers increased after adding portal phase images to arterial phase images ( p = 0.002), without additional benefit from dual energy images. In patients without GI bleeding, confidence in luminal extravasation appropriately decreased after adding portal phase, and subsequently DE images ( p = 0.006, p = 0.018). Conclusion A two-phase DE GI bleed CT protocol had high specificity and negative predictive value in clinical practice. Portal venous phase images improved diagnostic confidence in comparison to arterial phase images alone. Dual-energy images further improved radiologist confidence in the absence of bleeding.

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Evaluation of the Renal Venous System on Late Arterial and Venous Phase Images with MDCT Angiography in Potential Living Laparoscopic Renal Donors

American Journal of Roentgenology ◽

10.2214/ajr.184.2.01840539 ◽

2005 ◽

Vol 184 (2) ◽

pp. 539-545 ◽

Cited By ~ 50

Author(s):

Satomi Kawamoto ◽

Leo P. Lawler ◽

Elliot K. Fishman

Keyword(s):

Venous System ◽

Mdct Angiography ◽

Phase Images ◽

Venous Phase

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Discrimination of mediastinal metastatic lymph nodes in NSCLC based on radiomic features in different phases of CT imaging

10.21203/rs.2.11417/v2 ◽

2019 ◽

Author(s):

Xue Sha ◽

Guan Zhong Gong ◽

Qing Tao Qiu ◽

Jing Hao Duan ◽

Deng Wang Li ◽

...

Keyword(s):

Lymph Nodes ◽

Predictive Value ◽

Characteristic Curve ◽

Multivariate Logistic Regression Analysis ◽

Ct Images ◽

Ct Imaging ◽

Arterial Phase ◽

Metastatic Lymph Nodes ◽

Metastatic Lymph ◽

Venous Phase

Abstract Background: We aimed to develop radiomic models based on different phases of computed tomography (CT) imaging and to investigate the efficacy of models for diagnosing mediastinal metastatic lymph nodes (LNs) in non-small cell lung cancer (NSCLC). Methods: We selected 231 mediastinal LNs confirmed by pathology results as the subjects, which were divided into training (n=163) and validation cohorts (n=68). The regions of interest (ROIs) were delineated on CT scans in the plain phase, arterial phase and venous phase, respectively. Radiomic features were extracted from the CT images in each phase. A least absolute shrinkage and selection operator (LASSO) algorithm was used to select features, and multivariate logistic regression analysis was used to build models. We constructed six models (orders 1-6) based on the radiomic features of the single- and dual-phase CT images. The performance of the radiomic model was evaluated by the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV). Results: A total of 846 features were extracted from each ROI, and 10, 9, 5, 2, 2, and 9 features were chosen to develop models 1-6, respectively. All of the models showed excellent discrimination, with AUCs greater than 0.8. The plain CT radiomic model, model 1, yielded the highest AUC, specificity, accuracy and PPV, which were 0.926 and 0.925; 0.860 and 0.769; 0.871 and 0.882; and 0.906 and 0.870 in the training and validation sets, respectively. When the plain and venous phase CT radiomic features were combined with the arterial phase CT images, the sensitivity increased from 0.879 and 0.919 to 0.949 and 0979 and the NPV increased from 0.821 and 0.789 to 0.878 and 0.900 in the training group, respectively. Conclusions: All of the CT radiomic models based on different phases all showed high accuracy and precision for the diagnosis of LN metastasis (LNM) in NSCLC patients. When combined with arterial phase CT, the sensitivity and NPV of the model was be further improved.

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