Effects of Adaptive Statistical Iterative Reconstruction-V Technology on the Image Quality and Radiation Dose of Unenhanced and Enhanced CT Scans of the Piglet Abdomen.

To investigate the optimal pre- and post-adaptive statistical iterative reconstruction-V (ASiR-V) levels in pediatric abdominal computed tomography (CT) to minimize radiation exposure and maintain image quality using an animal model. A total of 10 standard piglets were selected and scanned to obtain unenhanced and enhanced images under different pre-ASiR-V conditions. The corresponding images were obtained using ASiR-V algorithm at different post-ASiR-V levels. CT value, signal-to-noise ratio (SNR), contrast noise ratio (CNR) of abdominal tissues, subjective image score, and radiation dose of unenhanced and enhanced scans were analyzed. With the increase of pre-ASiR-V level, the radiation dose in piglets gradually decreased (P < 0.05). Within the same group of pre-ASiR-V, the image noise was decreased (P < 0.05) by increasing post-ASiR-V level. There was no statistical difference between SNR and CNR values. In unenhanced CT, the subjective score of the images with the combination of 40% pre- and 60% post-ASiR-V levels had no statistical difference compared to the combination of 0% pre- and 60% post-ASiR-V levels, while the radiation dose decreased by 31.6%. In the enhanced CT, the subjective image score with the 60% pre- and 60% post-ASiR-V combination had no statistical difference compared to the 0% pre- and 60% post-ASiR-V combination, while the radiation dose was reduced by 48.9%. The combined use of pre- and post-ASiR-V maintains image quality at the reduced radiation dose. The optimal level for unenhanced CT is 40% pre-combined with 60% post-ASiR-V, while that for enhanced CT is 60% pre-combined with 60% post-ASiR-V in pediatric abdominal CT.

Exposure-time-dependent subcellular staging of gold nanoparticles deposition and vesicle destruction in mice livers.

Several advances in nanomedicine have been accompanied by rising concerns about the bioaccumulation and toxicity of gold nanoparticles (AuNPs). Here, we assessed the in vivo fate of diversely sized AuNPs that were injected into mice as a computed tomography contrast agent and examined with multi-scale analyses across the organ, tissue, cell, and subcellular levels. After focusing on the strong detected accumulation in livers, our data revealed a set of three clear, exposure-time-dependent patterns based on i) AuNPs deposit morphology and ii) readily identifiable phenotypes for AuNP-impacted subcellular vesicles. Importantly, we detected no obvious differences in liver function, liver cell apoptosis, or autophagy upon exposure to AuNPs. Thus, our study illustrates an accessible experimental and high-resolution data interpretation framework for quickly obtaining and contextualizing informative trends about any AuNP-triggered patterns of subcellular damage in nanomedicine studies; these can help guide cytotoxity and safety testing of diagnostic nanomedical technologies.

Monochromatic energy computed tomography image for active intestinal hemorrhage: a model investigation.

AIM: To investigate the value of computed tomography (CT) spectral imaging in the evaluation of intestinal hemorrhage. METHODS: Seven blood flow rates were simulated in vitro. Energy spectral CT and mixed-energy CT scans were performed for each rate (0.5, 0.4, 0.3, 0.2, 0.1, 0.05 and 0.025 mL/min). The detection rates and the contrast-to-noise ratios (CNRs) of the contrast agent extravasation regions were compared between the two scanning methods in the arterial phase (AP) and the portal venous phase (PVP). Comparisons of the CNR values between the PVP and the AP were made for each energy level and carried out using a completely random t test. A χ (2) test was used to compare the detection rates obtained from the two scanning methods. RESULTS: The total detection rates for energy spectral CT and mixed-energy CT in the AP were 88.57% (31/35) and 65.71% (23/35), respectively, and the difference was significant (χ (2) = 5.185, P = 0.023); the total detection rates in the PVP were 100.00% (35/35) and 91.4% (32/35), respectively, and the difference was not significant (χ (2) = 1.393, P = 0.238). In the AP, the CNR of the contrast agent extravasation regions was 3.58 ± 2.09 on the mixed-energy CT images, but the CNRs were 8.78 ± 7.21 and 8.83 ± 6.75 at 50 and 60 keV, respectively, on the single-energy CT images, which were significantly different (3.58 ± 2.09 vs 8.78 ± 7.21, P = 0.031; 3.58 ± 2.09 vs 8.83 ± 6.75, P = 0.029). In the PVP, the differences between the CNRs at 40, 50 and 60 keV different monochromatic energy levels and the polychromatic energy images were significant (19.35 ± 10.89 vs 11.68 ± 6.38, P = 0.010; 20.82 ± 11.26 vs 11.68 ± 6.38, P = 0.001; 20.63 ± 10.07 vs 11.68 ± 6.38, P = 0.001). The CNRs at the different energy levels in the AP and the PVP were significantly different (t = -2.415, -2.380, -2.575, -2.762, -2.945, -3.157, -3.996 and -3.189). CONCLUSION: Monochromatic energy imaging spectral CT is superior to polychromatic energy images for the detection of intestinal hemorrhage, and the detection was easier in the PVP compared with the AP.

Clinical values of of gemstone spectral CT in diagnosing thyroid disease.

OBJECTIVE: To quantitatively evaluate the diagnostic value of gemstone spectral CT in thyroid disease. PATIENTS AND METHODS: A total of 123 patients with thyroid diseases were enrolled in the retrospective study. All the patients underwent spectral CT scan, and 39 of them underwent dual-phase enhanced scan. Iodine concentration (IC) and normalized IC (NIC) were compared between benign and malignant nodules. The optimal threshold to predict malignancy was obtained by receiver operating characteristic curve (ROC). Multivariate ROC analysis was performed to evaluate the efficacy of combining the IC (NIC) and conventional morphological characteristics. RESULTS: Ten diffuse diseases and 113 nodular diseases were confirmed by clinical laboratory examination and histopathology. In total, 122 nodules (87 benign and 35 malignant) were detected, 41 nodules in enhanced cases. The IC and NIC_{VP} of malignant nodules were significantly lower than benign nodules in noncontrast and venous phase (VP) (P=0.000). The optimal IC and NIC_{VP} threshold was 0.68 mg/mL and 0.38, achieving 74.3% and 76.9% sensitivity, 66.7% and 80.0% specificity, respectively. For multivariate analysis, the area under ROC (AUC) was 0.88 and 0.94 in noncontrast and VP, respectively. Sensitivities of 77.1% and 84.6%, and specificities of 84.5% and 88.0% were achieved. CONCLUSION: Gemstone spectral CT can generally evaluate the abnormal iodine content in thyroid disease. Lower iodine can help differentiating malignant from benign nodules. A comprehensive analysis combining spectrum parameters and morphological characteristics is suggested in differential diagnosis.

Value of diffusion-weighted magnetic resonance imaging on the follow-up of nasopharyngeal carcinoma after radiotherapy.

PURPOSE: To explore the value of diffusion-weighted imaging (DWI) and magnetic resonance imaging (MRI) on the follow-up of nasopharyngeal carcinoma (NPC) after radiotherapy. MATERIAL AND METHODS: Eighty-three NPC patients after radiotherapy were divided into two groups: 4 cases of residual tumor and 33 cases of non-residual within 6 months, the cases of recurrent and non-recurrent were 5 and 41 over 6 months, respectively. MRI and DWI imaging of these cases were closely analyzed, and the apparent diffusion coefficient (ADC) of the nasopharyngeal residual mass and nasopharyngeal wall thickening, skull base destruction and lateral pterygoid muscle were measured. RESULTS: The ADC of the lateral pterygoid muscle was (1.501 ± 0.069) × 10^{ - 3} mm^{2}/s in 83 cases. The ADCs of the non-residual group, residual group, non-recurrent group and recurrent group were (1.843 ± 0.133.4) × 10^{ - 3} mm^{2}/s, (1.097 ± 0.183) × 10^{ - 3} mm^{2}/s, (1.884 ± 0.134) × 10^{ - 3} mm^{2}/s and (0.787 ± 0.067) × 10^{ - 3} mm^{2}/s respectively.The ADCs of the residual group and recurrent group were lower than that of the lateral pterygoid muscle, while the ADCs of the non-residual group and non-recurrent group were higher than that of the lateral pterygoid muscle.The differences were statistically significant (P < 0.05). CONCLUSION: DWI can provide qualitative and quantitative information about the tumor cellular level; it can also identify residual, local fibrosis and recurrence after NPC radiotherapy sensitively and accurately by measuring the ADC of the region of interest.

Correlation between CT attenuation value and iodine concentration in vitro: discrepancy between gemstone spectral imaging on single-source dual-energy CT and traditional polychromatic X-ray imaging.

INTRODUCTION: To assess the relation between CT attenuation value and iodine concentration in vitro, using gemstone spectral imaging (GSI) with single-source dual-energy CT and traditional polychromatic X-ray imaging (TPXI), respectively. METHODS: A polypropylene phantom with eight test tubes in which iodine concentrations of solution were 0.4, 0.7, 2, 5, 10, 20, 30 and 50 mg/mL underwent GSI and traditional polychromatic X-ray scans (80, 100, 120 and 140 kV(p)), using single-source dual-energy spectral CT (Discovery CT750HD; GE Healthcare Technologies, Milwaukee, WI, USA) at the same tube speed of 0.8 s/rotation. All spectral imaging data were analysed with GSI viewer to obtain monochromatic images (50-140 keV, interval of 10 keV). Computed tomography attenuation values of iodine solution were measured with the same size of regions of interest and at the exact same level for both monochromatic and polychromatic images. The relation between CT attenuation value and iodine concentration was examined. RESULTS: A linear correlation was found between CT attenuation value and iodine concentration for both monochromatic and polychromatic images. Moreover, the fitting coefficients for CT attenuation values and iodine concentrations were closer to one with GSI (r(2) = 0.99824-0.99996) than that with TPXI (r(2) = 0.99640-0.99736). CONCLUSIONS: Owing to the better correlation coefficients between CT attenuation value and iodine concentration, GSI may be a preferred method for quantitative measurement compared with TPXI.

Hepatic veno-occlusive disease after taking Gynura Rhizome: The value of multidetector computed tomography in diagnosing the disease and evaluating the clinical therapeutic effect.

AIM: We conducted this study to evaluate the role of multidetector computed tomography (MDCT) in diagnosing and differential diagnosis hepatic veno-occlusive disease (HVOD), and as well as assessing the clinical therapeutic effects. METHODS: From 2007 to 2010, 10 inpatients with weight increasing, liver pains, ascites, jaundice and history of taking gynura rhizome before hospitalization were scanned with a 64-MDCT. The data were reconstructed every 0.625 mm and reviewed using multiplanar reconstruction (MPR) and liver CT angiography (CTA) on a GE AW4.2 workstation. Patients were re-scanned with MDCT after medication so that the clinical therapeutic effect could be evaluated before the patients discharging from hospital. RESULTS: In 10 HVOD patients, the diagnoses of MDCT were coincident with clinical results. All patients had ascites and pleural fluid, hepatomegaly except the caudate lobe in MDCT. Failure to view hepatic veins in hepatic 3 phase scans, but portal veins and inferior vena cava were unobstructed. In portal-phase, hepatic enhancements were non-uniform. Three patients were incorrectly diagnosed before hospital admission. All patients improved significantly after hepato-protection and supporting therapy. No ascites, hydrothorax, hepatomegaly and obstruction of hepatic veins were observed by MDCT before patients were discharged from hospital. CONCLUSION: Multidetector computed tomography combined with MPR and liver CTA images are helpful in the diagnosis and differential diagnosis of HVOD and in the evaluation of clinical therapeutic effects.

Impact of different window settings on colon polyp measurements with CT virtual colonoscopy: a phantom study.

The aim of this study was to evaluate the impact of window settings on measurement of colon polyps with CT virtual colonoscopy with experiment. Twenty-four artificial polyps' diameter were measured and scanned 10 times with identical scan parameters using a 64-multidetector computed tomographic scanner. The diameter of each polyp was measured using lung window and abdominal soft tissue window settings and compared with the actual diameter. The lung window setting offers accurate measurement of colon polyps.

CT virtual colonoscopy in displaying excavated colon lesions.

The aim of this study was to evaluate the relative values of 2D plane view and 3D intracavity view of CT virtual colonoscopy in displaying colon excavated lesions. Cleaned porcine colon with ulcerative lesion was scanned with multidetector CT. The data were reconstructed and reviewed using 2D plane view and 3D volume-rendered images on a GE AW4.2 workstation. The 3D volume-rendered images showed superiority in displaying excavated lesions.