Virtual unenhanced phase with spectral dual-energy CT: Is it an alternative to conventional true unenhanced phase for abdominal tissues?

Jamali, Sanaa; Michoux, Nicolas; Coche, Emmanuel; Dragean, Cristina

doi:10.1016/j.diii.2019.04.007

Cited by 44 publications

(39 citation statements)

References 20 publications

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“…This also demonstrates a major advantage of DECT: the possibility to create VNC images from a contrast-enhanced examination [ 15 ] and perform HU analyses on these. The fact that VNC and real non-contrast-enhanced HU values in the muscles are either not significantly different or show a difference of less than 2 HU in absolute numbers has been previously demonstrated [ 31 – 33 ]. Sarcopenia cut-off values for SMRA from non-contrast-enhanced single-energy CT scans should thus hypothetically be applicable to VNC images of contrast-enhanced DECT scans.…”

Section: Discussionmentioning

confidence: 99%

Skeletal muscle fat quantification by dual-energy computed tomography in comparison with 3T MR imaging

et al. 2021

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Objectives To quantify the proportion of fat within the skeletal muscle as a measure of muscle quality using dual-energy CT (DECT) and to validate this methodology with MRI. Methods Twenty-one patients with abdominal contrast-enhanced DECT scans (100 kV/Sn 150 kV) underwent abdominal 3-T MRI. The fat fraction (DECT-FF), determined by material decomposition, and HU values on virtual non-contrast-enhanced (VNC) DECT images were measured in 126 regions of interest (≥ 6 cm2) within the posterior paraspinal muscle. For validation, the MR-based fat fraction (MR-FF) was assessed by chemical shift relaxometry. Patients were categorized into groups of high or low skeletal muscle mean radiation attenuation (SMRA) and classified as either sarcopenic or non-sarcopenic, according to the skeletal muscle index (SMI) and cut-off values from non-contrast-enhanced single-energy CT. Spearman’s and intraclass correlation, Bland-Altman analysis, and mixed linear models were employed. Results The correlation was excellent between DECT-FF and MR-FF (r = 0.91), DECT VNC HU and MR-FF (r = - 0.90), and DECT-FF and DECT VNC HU (r = − 0.98). Intraclass correlation between DECT-FF and MR-FF was good (r = 0.83 [95% CI 0.71–0.90]), with a mean difference of - 0.15% (SD 3.32 [95% CI 6.35 to − 6.66]). Categorization using the SMRA yielded an eightfold difference in DECT VNC HU values between both groups (5 HU [95% CI 23–11], 42 HU [95% CI 33–56], p = 0.05). No significant relationship between DECT-FF and SMI-based classifications was observed. Conclusions Fat quantification within the skeletal muscle using DECT is both feasible and reliable. DECT muscle analysis offers a new approach to determine muscle quality, which is important for the diagnosis and therapeutic monitoring of sarcopenia, as a comorbidity associated with poor clinical outcome. Key Points • Dual-energy CT (DECT) material decomposition and virtual non-contrast-enhanced DECT HU values assess muscle fat reliably. • Virtual non-contrast-enhanced dual-energy CT HU values allow to differentiate between high and low native skeletal muscle mean radiation attenuation in contrast-enhanced DECT scans. • Measuring muscle fat by dual-energy computed tomography is a new approach for the determination of muscle quality, an important parameter for the diagnostic confirmation of sarcopenia as a comorbidity associated with poor clinical outcome.

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Section: Discussionmentioning

confidence: 99%

Skeletal muscle fat quantification by dual-energy computed tomography in comparison with 3T MR imaging

et al. 2021

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“…Using dual-energy CT, virtual non-contrast CT images can be synthesized, which could replace a precontrast CT scan, thereby reducing radiation exposure [34]. In previous studies, CT-attenuation values of various organs in virtual non-contrast CT images have shown close agreement with those in true unenhanced CT images [35,36]. Therefore, future studies are needed to clarify whether CT-attenuation of breast adipose tissue measured on virtual non-contrast CT images of dual-energy CT also has prognostic significance in breast cancer patients, which may form an imaging protocol for evaluating both tumor factors and tumor-adjacent breast tissue factors using a single CT scan.…”

Section: Discussionmentioning

confidence: 99%

Prognostic Significance of CT-Attenuation of Tumor-Adjacent Breast Adipose Tissue in Breast Cancer Patients with Surgical Resection

Lee

Kim

Lee

et al. 2019

Cancers

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The purpose of this study was to evaluate the prognostic significance of computed tomography (CT)-attenuation of tumor-adjacent breast adipose tissue for predicting recurrence-free survival (RFS) in patients with breast cancer. We retrospectively enrolled 287 breast cancer patients who underwent pretreatment 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. From non-contrast-enhanced CT images of PET/CT, CT-attenuation values of tumor-adjacent breast adipose tissue (TAT HU) and contralateral breast adipose tissue (CAT HU) were measured. Difference (HU difference) and percent difference (HU difference %) in CT-attenuation values between TAT HU and CAT HU were calculated. The relationships of these breast adipose tissue parameters with tumor factors and RFS were assessed. TAT HU was significantly higher than CAT HU (p < 0.001). TAT HU, HU difference, and HU difference % showed significant correlations with T stage and estrogen receptor and progesterone receptor status (p < 0.05), whereas CAT HU had no significant relationships with tumor factors (p > 0.05). Patients with high TAT HU, HU difference, and HU difference % had significantly worse RFS than those with low values (p < 0.001). In multivariate analysis, TAT HU and HU difference % were significantly associated with RFS after adjusting for clinico-pathologic factors (p < 0.05). CT-attenuation of tumor-adjacent breast adipose tissue was significantly associated with RFS in patients with breast cancer. The findings seem to support the close contact between breast cancer cells and tumor-adjacent adipocytes observed with imaging studies.

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“…Although the VNCs have been demonstrated lower quality compared to TNCs, indeed they are suffi cient for reporting, and they are a helpful means to obtain un-enhanced images from a single dataset with contrast medium, thus further scans are not needed. A dose reduction of the VNCs is widely demonstrated [13][14][15][16], almost halved, this is important in young patients in which DE scans can be used routinely. However several conditions can give unsure results, for example, we said that x-ray dual energy levels well distinguish Iodine materials, but other elements can be same to Iodine in attenuation measurements such as some metallic stitches, some endovascular prosthesis, gallstones [17], and some kinds of calcifi cations, that may be likewise subtracted in VNC reconstruction processing.…”

Section: Final Considerationsmentioning

confidence: 99%

Dual Energy on Dual Source CT in Abdominal Imaging

Francesco

Orlando

Francesco

et al. 2020

JAHC

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Establish whether virtual non-contrast images can replace real non-contrast images, avoiding the preliminary scan, thus saving the patient dose. Forty-one patients were studied on a second-generation dual-source scanner, triphasic were applied on all patients, arterial and venous phase was acquired in dual-energy. HU values of TNC and VNC scans were compared through ROI on liver, spleen, kidneys, aorta, muscle, and fat. Qualitative analysis of the data sets was performed by four readers and the values from 1 to 4 (1. poor, 2. fair, 3. good, 4. excellent.) were assigned to define the diagnostic quality of the images. Then the absorbed dose ratios between the virtual images and the pre-contrast and portal phase images were compared. HU values were analyzed with the t-test and the difference was statistically significant P<0.0001. Image quality was evaluated as excellent or good in 91,3% of TNC and 81,6% of VNC. At last, VNC showed a sensitive dose reduction -46% compared to conventional triphasic protocol. Overall VNC has shown a good image quality comparable to TNC. The dose reduction obtained from the extraction of images without iodine, avoiding further scans, suggests the use of the dual-energy protocol in many exams.

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Virtual unenhanced phase with spectral dual-energy CT: Is it an alternative to conventional true unenhanced phase for abdominal tissues?

Cited by 44 publications

References 20 publications

Skeletal muscle fat quantification by dual-energy computed tomography in comparison with 3T MR imaging

Skeletal muscle fat quantification by dual-energy computed tomography in comparison with 3T MR imaging

Prognostic Significance of CT-Attenuation of Tumor-Adjacent Breast Adipose Tissue in Breast Cancer Patients with Surgical Resection

Dual Energy on Dual Source CT in Abdominal Imaging

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