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Purpose/Aim of the study. To assess the feasibility of krypton-enhanced ventilation CT using dual energy (DE) technique for various krypton concentrations and to determine the appropriate krypton concentration for DE ventilation CT through an animal study. Materials and Methods. Baseline DECT was first performed on seven New Zealand white rabbits. The animals were then ventilated using 20%, 30%, 40%, 50%, 60%, to 70% krypton concentration, and DECT was performed for each concentration. Krypton extraction was performed through a workstation, and results were displayed on a color map. Overlay Hounsfield unit (HU) values were obtained by two observers in consensus readings. A linear mixed model was used to correlate overlay HU values and krypton concentrations. Visual assessments of the homogeneity of krypton maps were also performed. Results. Mean overlay HU values according to krypton concentration were as follows; 20% krypton, 1.68 ± 5.15; 30% krypton, 3.73 ± 5.93; 40% krypton, 6.92 ± 5.51; 50% krypton, 10.88 ± 5.17; 60% krypton, 14.54 ± 4.23; and 70% krypton, 18.79 ± 3.63. We observed a significant correlation between overlay HU values on krypton maps and krypton concentrations ( P < .001). For the krypton color maps, all observers determined universal enhancement on the 70% krypton map for all animals. Conclusion. It is feasible to evaluate lung ventilation function using DECT with a krypton concentration of at least 70%. [ABSTRACT FROM AUTHOR]

This study was carried out to demonstrate whether the radiation dose for patients in arms-down position can be reduced without affecting the diagnosis on abdominal computed tomography (CT). The patients were divided into two groups: group A, which included patients with arms-down position using dose modulation on, and group B, which included patients with arms-down position using dose modulation turned off. Quantitative evaluation was compared using Hounsfield units, standard deviation, and signal-to-noise ratio of the four regions. The qualitative evaluation was assessed for overall image quality, subjective image noise, and beam hardening artifacts. Dose evaluation for CT dose index (CTDI) and dose length product (DLP) was compared by comparing the CT images with dose modulation turned on and off. In the quantitative and qualitative evaluation, there was no statistically significant difference between groups A and B (p > 0.05). In the dose evaluation, the CT images with dose modulation turned off had significantly lower CTDI and DLP than the CT images with dose modulation turned on (p < 0.05). Our results suggest that, for the GE Revolution EVO CT scanner, turning off dose modulation and increasing the tube voltage can reduce the radiation dose for patients with the arms-down position without affecting the diagnosis. This study did not consider the change of tube potential according to the use of dose modulation, and we plan to conduct additional research in the future. [ABSTRACT FROM AUTHOR]

We assessed the role of F-18 FDG PET/CT in evaluating isolated extra-axillary lymph node recurrences in postoperative breast cancer patients and its prognostic value on clinical outcome. We reviewed PET/CT scans of postoperative breast cancer patients performed at our institution between July 2003 and February 2012. We recorded PET/CT findings, clinicopathologic variables and treatment modalities. We analyzed metabolic parameters from PET/CT and clinicopathologic variables with respect to progression free survival (PFS). A total of 3561 PET/CT scans were performed in 1906 postoperative breast cancer patients with a median interval of 43 month from curative surgery. Fifty seven patients (2.99%) demonstrated isolated extra-axillary nodal recurrences (n=85) on PET/CT (internal mammary node recurrences in 28, supraclavicular 24, infraclavicular 4, interpectoral 8, cervical 12, and mediastinal 9).The median SUVmax was 7.8 (range, 1.8~19.0), and the median node size was 15 mm (range, 6~38 mm). All recurrences were nonpalpable. Based on PET/CT findings, 53 out of 57 patients with extra-axillary node recurrences underwent subsequent chemotherapy/radiation therapy. The estimated 3-year PFS rate was 48.6%. Cutoff points of SUVmax 2.7 and size 14 mm were the best discriminative values for predicting clinical outcome. SUVmax and size of extra-axillary nodal recurrences were significantly correlated to PFS on univariate and multivariate analyses (p<0.001 and p=0.019, respectively). [ABSTRACT FROM AUTHOR]

Conventional thermosetting composites exhibit advantageous mechanical properties owing to the use of an autoclave; however, their wide usage is limited by high production costs and long molding times. In contrast, the fabrication of thermoplastic composites involves out-of-autoclave processes that use press equipment. In particular, induction-heating molding facilitates a quicker thermal cycle, reduced processing time, and improved durability of the thermoplastic polymers; thus, the process cost and production time can be reduced. In this study, carbon fiber/polyphenylene sulfide thermoplastic composites were manufactured using induction-heating molding, and the relationships among the process, structure, and mechanical properties were investigated. The composites were characterized using optical and scanning electron microscopy, an ultrasonic C-scan, and X-ray computed tomography. In addition, the composites were subjected to flammability tests. This study provides novel insights into the optimization of thermoplastic composite manufacturing and thermoset composite curing processes. [ABSTRACT FROM AUTHOR]

As a result of recent developments in imaging modalities and wide spread routine medical checkups and screening, more incidental liver lesions are found frequently on US these days. When incidental liver lesions are found on US, physicians have to make a decision whether to just follow up or to undergo additional imaging studies for lesion characterization. In order to choose the next appropriate imaging modality, the diagnostic accuracy of each imaging study needs to be considered. Therefore, we tried to compare the accuracy of contrast-enhanced multidetector CT (MDCT) and Gd-EOB-DTPA-enhanced MRI for characterization of incidental liver masses. We included 127 incidentally found focal liver lesions (94 benign and 33 malignant) from 80 patients (M∶F = 45∶35) without primary extrahepatic malignancy or chronic liver disease. Two radiologists independently reviewed Gd-EOB-DTPA-enhanced MRI and MDCT. The proportion of confident interpretations for differentiation of benign and malignant lesions and for the specific diagnosis of diseases were compared. The proportion of confident interpretations for the differentiation of benign and malignant lesions was significantly higher with EOB-MRI(94.5%–97.6%) than with MDCT (74.0%–92.9%). In terms of specific diagnosis, sensitivity and accuracy were significantly higher with EOB-MRI than with MDCT for the diagnosis of focal nodular hyperplasia (FNH) and focal eosinophilic infiltration. The diagnoses of the remaining diseases were comparable between EOB-MRI and MDCT. Hence, our results suggested that Gd-EOB-MRI may provide a higher proportion of confident interpretations than MDCT, especially for the diagnosis of incidentally found FNH and focal eosinophilic infiltration. [ABSTRACT FROM AUTHOR]

We assessed the role of F-18 FDG PET/CT in evaluating isolated extra-axillary lymph node recurrences in postoperative breast cancer patients and its prognostic value on clinical outcome. We reviewed PET/CT scans of postoperative breast cancer patients performed at our institution between July 2003 and February 2012. We recorded PET/CT findings, clinicopathologic variables and treatment modalities. We analyzed metabolic parameters from PET/CT and clinicopathologic variables with respect to progression free survival (PFS). A total of 3561 PET/CT scans were performed in 1906 postoperative breast cancer patients with a median interval of 43 month from curative surgery. Fifty seven patients (2.99%) demonstrated isolated extra-axillary nodal recurrences (n=85) on PET/CT (internal mammary node recurrences in 28, supraclavicular 24, infraclavicular 4, interpectoral 8, cervical 12, and mediastinal 9).The median SUVmax was 7.8 (range, 1.8~19.0), and the median node size was 15 mm (range, 6~38 mm). All recurrences were nonpalpable. Based on PET/CT findings, 53 out of 57 patients with extra-axillary node recurrences underwent subsequent chemotherapy/radiation therapy. The estimated 3-year PFS rate was 48.6%. Cutoff points of SUVmax 2.7 and size 14 mm were the best discriminative values for predicting clinical outcome. SUVmax and size of extra-axillary nodal recurrences were significantly correlated to PFS on univariate and multivariate analyses (p<0.001 and p=0.019, respectively). [ABSTRACT FROM AUTHOR]

Background: An aberrant left hepatic artery is frequently encountered during upper gastrointestinal surgery, and researchers have yet to propose optimal strategies with which to address this arterial variation. The objective of this study was to determine whether the areas perfused by an aberrant left hepatic artery can be visualized in real-time using near-infrared fluorescence imaging with indocyanine green. Methods: Patients with gastric adenocarcinoma who underwent minimally invasive radical gastrectomy from May 2018 to August 2019 were enrolled and retrospectively analyzed at a single-center. Patients with an aberrant left hepatic artery and normal preoperative liver function were examined. After the clamping of an aberrant left hepatic artery, indocyanine green was administered via a peripheral intravenous route during surgery. Fluorescence at the liver was visualized under near-infrared fluorescence imaging. Results: In 31 patients with aberrant left hepatic arteries, near-infrared fluorescence imaging was used without adverse events associated with indocyanine green. Six (19%) patients were reported to have an aberrant left hepatic artery upon preoperative CT imaging, while all other instances were detected during surgery. Fluorescence excitation on the liver was, on average, visible after 43 s (range, 25–65). Fluorescence across the entire surface of the liver was noted in 20 (65%) patients in whom the aberrant left hepatic artery could be ligated. Aberrant left hepatic arteries were safely preserved in 10 (32%) patients who showed areas of no or partial fluorescence excitation. Guided by near-infrared fluorescence imaging, ligation of aberrant left hepatic arteries elicited no significant changes in postoperative liver function. Conclusion: Near-infrared fluorescence imaging facilitates the identification of aberrant left hepatic arterial territories, guiding decisions on the preservation or ligation of this arterial variation. [ABSTRACT FROM AUTHOR]

This retrospective study investigated whether repetitive exposure to intravenous iodinated contrast media (ICM) affects long-term renal function in patients who undergo curative surgery for early gastric cancer (EGC) collected from the Korean Health Insurance and Review Assessment (HIRA) database. Patients diagnosed with gastric cancer between January 2010 and December 2013 underwent regular computed tomography (CT) scans to monitor for extragastric recurrence. Patients who already had chronic kidney disease (CKD) before cancer diagnosis or had undergone chemotherapy or repeated surgery were excluded. A nested case–control study design was chosen to analyze the effect of repetitive ICM exposure to long-term renal function by comparing patients who developed CKD 2 years after cancer diagnosis and patients who did not. Among 59,971 patients collected according to inclusion and exclusion criteria, 1021 were diagnosed with CKD 2 years after cancer diagnosis. Using 1:5 matching after adjusting for age, sex and date of cancer diagnosis, 5097 control patients were matched to 1021 CKD patients. Conditional logistic regression showed that the number of CTs taken using ICM slightly increased the odds of CKD (odds ratio, 1.080; 95% confidence interval (CI): 1.059, 1.100; P < 0.0001). Thus, the administration of ICM might contribute to chronic renal function impairment. [ABSTRACT FROM AUTHOR]

Purpose This study aims to propose a physics-based method of reducing beam-hardening artifacts induced by high-attenuation materials such as metal stents or other metallic implants. Methods The proposed approach consists of deriving a sinogram inconsistency formula representing the energy dependence of the attenuation coefficient of high-attenuation materials. This inconsistency formula more accurately represents the inconsistencies of the sinogram than that of a previously reported formula (called the MAC- BC method). This is achieved by considering the properties of the high-attenuation materials, which include the materials' shapes and locations and their effects on the incident X-ray spectrum, including their attenuation coefficients. Results Numerical simulation and phantom experiment demonstrate that the modeling error of MAC- BC method are nearly completely removed by means of the proposed method. Conclusion The proposed method reduces beam-hardening artifacts arising from high-attenuation materials by relaxing the assumptions of the MAC- BC method. In doing so, it outperforms the original MAC- BC method. Further research is required to address other potential sources of metal artifacts, such as photon starvation, scattering, and noise. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The aim of this study was to determine the registration error of an ultrasound (US) fusion imaging system during an ex vivo study and its clinical value for percutaneous radiofrequency ablation (pRFA) during an in vivo study. Materials and methods: An ex vivo study was performed using 4 bovine livers and 66 sonographically invisible lead pellets. Real-time CT-US fusion imaging was applied to assist the targeting of pellets with needles in each liver; the 4 sessions were performed by either an experienced radiologist (R1, 3 sessions) or an inexperienced resident (R2, 1 session). The distance between the pellet target and needle was measured. An in vivo study was retrospectively performed with 51 nodules (42 HCCs and 9 metastases; mean diameter, 16mm) of 37 patients. Fusion imaging was used to create a sufficient safety margin (>5mm) during pRFA in 24 nodules (group 1), accurately target 21 nodules obscured in the US images (group 2) and precisely identify 6 nodules surrounded by similar looking nodules (group 3). Image fusion was achieved using MR and CT images in 16 and 21 patients, respectively. The reablation rate, 1-year local recurrence rate and complications were assessed. Results: In the ex vivo study, the mean target–needle distances were 2.7mm±1.9mm (R1) and 3.1±3.3mm (R2) (p >0.05). In the in vivo study, the reablation rates in groups 1–3 were 13%, 19% and 0%, respectively. At 1year, the local recurrence rate was 11.8% (6/51). In our assessment of complications, one bile duct injury was observed. Conclusion: US fusion imaging system has an acceptable registration error and can be an efficacious tool for overcoming the major limitations of US-guided pRFA. [Copyright &y& Elsevier]

Objectives: Contrast-induced acute kidney injury (CI-AKI) is one of the leading causes of new-onset renal failure in hospitalized patients. Statin has been evaluated for its protective effect against CI-AKI but rarely in patients receiving intravenous (IV) administrations of iodine-based contrast media for enhanced computed tomography (CT).Methods: In total, 12,371 patients who underwent contrast-enhanced abdominopelvic CT were retrospectively reviewed and stratified into statin users and statin nonusers. Subgroup analyses comparing high-intensity statins with low- to moderate-intensity statins were conducted within statin users and similar comparisons were performed within statin users stratified based on baseline eGFR.Results: Overall, CI-AKI events did not occur less in statin users compared with non-statin users (p = 0.342). Within statin users, CI-AKI events did not decrease in high-intensity statin users compared with low- to moderate-intensity statin users (p = 0.355). Moreover, no significant difference in CI-AKI events was found between high-intensity statin users and low- to moderate-intensity statin users even after stratifying the patients with baseline eGFR.Conclusions: Collectively, statin was not significantly associated with the risk of CI-AKI events in patients undergoing contrast-enhanced abdominopelvic CT and high-intensity statins did not show significant association with CI-AKI over low- to moderate-intensity statins in the subgroup analysis.Key Points: • Statin is not associated with risk of CI-AKI events in patients undergoing intravenous administration of contrast-enhanced CT. • CI-AKI incidence among high-intensity statin users was not significantly different from that of low- to moderate-intensity statin users. [ABSTRACT FROM AUTHOR]

Purpose: This paper proposes a sinogram‐consistency learning method to deal with beam hardening‐related artifacts in polychromatic computerized tomography (CT). The presence of highly attenuating materials in the scan field causes an inconsistent sinogram that does not match the range space of the Radon transform. When the mismatched data are entered into the range space during CT reconstruction, streaking and shading artifacts are generated owing to the inherent nature of the inverse Radon transform Methods: The proposed learning method aims to repair inconsistent sinogram by removing the primary metal‐induced beam hardening factors along the metal trace in the sinogram. Taking account of the fundamental difficulty in obtaining sufficient training data in a medical environment, the learning method is designed to use simulated training data and a patient's implant type‐specific learning model is used to simplify the learning process. Results: The feasibility of the proposed method is investigated using a dataset, consisting of real CT scans of pelvises containing simulated hip prostheses. The anatomical areas in training and test data are different, in order to demonstrate that the proposed method extracts the beam hardening features, selectively. The results show that our method successfully corrects sinogram inconsistency by extracting beam hardening sources by means of deep learning. Conclusion: This paper proposed a deep learning method of sinogram correction for beam hardening reduction in CT for the first time. Conventional methods for beam hardening reduction are based on regularizations, and have the fundamental drawback of being not easily able to use manifold CT images, while a deep learning approach has the potential to do so. [ABSTRACT FROM AUTHOR]

Although N-methyl- d-aspartate (NMDA) receptor antagonists may have beneficial influences on cognition in patients with alcohol-related dementia (ARD), their effects on regional cerebral blood flow (rCBF) remain unknown. This study evaluated changes in rCBF in ARD patients after administration of NMDA receptor antagonist for 12 weeks using technetium-99m ethyl cysteinate dimer (Tc-99m ECD) single-photon emission computed tomography (SPECT). Twenty-eight ARD patients were administered memantine for 12 weeks and underwent clinical evaluations and brain SPECT scans at baseline and follow-up. Whole-brain changes in perfusion were examined on a voxel-by-voxel basis. At follow-up, the patients showed reduced rCBF in the left medial frontal gyrus, left cingulate gyrus, left claustrum, right brainstem, left superior temporal gyrus, bilateral fusiform gyrus, and left cerebellum. On the other hand, increased rCBF was found in the bilateral uncus, left parahippocampal gyrus, bilateral superior frontal gyrus, right inferior parietal lobule, left cuneus, and left superior temporal gyrus. Perfusion increases in various brain areas including the superior frontal, parahippocampal, and inferior parietal areas, which may play important roles in the pathophysiology of ARD, suggest potential benefits of NMDA receptor antagonists on brain functions in patients with ARD. [ABSTRACT FROM AUTHOR]

Gamma-ray computed tomography (CT) has widely been used to inspect cracks, obstructions, and fluid flow in pipes. Previous studies have shown that the inspection accuracy is limited when materials in the pipe have a similar density. To overcome this drawback, we investigated a method to discriminate small density differences using a dual-energy gamma-ray CT. In this paper, the performance of a gamma-ray CT system was simulated using Geant4 Application for Tomographic Emission with three types of sources (Am-241, Co-57, and Cs-137). A polyvinyl chloride (PVC) pipe containing oil and sludge was modeled as a phantom. Sparsely acquired data were reconstructed using filtered back-projection and iterative total variation (TV) denoising algorithms. Each material discrimination procedure was performed with a postreconstruction technique. Our results clearly showed that the gamma-ray CT imaging with Am-241 and Co-57 sources and the TV denoising reconstruction algorithm can be used to inspect the internal structures based on discriminated images. The calculated areas of discriminated oil and sludge were within an error margin of 2% (oil: 78.4% and sludge: 21.6%) compared with the simulated phantom (oil: 80% and sludge: 20%). For both gamma sources, the calculated contrast-to-noise ratio (CNR) values with the TV denoising algorithm were the highest values for all structures (Am-241/Co-57: 18.03/28.95 for oil versus sludge, 41.67/31.53 for oil versus PVC pipe, and 23.64/31.53 for sludge versus PVC pipe). The feasibility of our approach and results indicates it usefulness for industrial fields that require structural inspections. [ABSTRACT FROM PUBLISHER]

Purpose: We evaluated the prognostic value of pretreatment F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) who had received curative treatment or transarterial chemoembolization (TACE). Methods: Between 2009 and 2010, 317 patients diagnosed with HCC at seven hospitals were enrolled. Among these, 195 patients underwent curative treatments including resection, liver transplantation, and radiofrequency ablation. TACE was performed in 122 patients. The tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor was measured using pretreatment FDG PET/CT. The prognostic significance of TLR and other clinical variables was assessed using Cox regression models. Differences in the overall survival (OS) associated with TLR or other significant clinical factors were examined using the Kaplan-Meier method. Results: Over a median follow-up period of 46 months, 77 patients died from cancer. In the curative cohort, higher TLR (≥2) was significantly associated with death (hazard ratio [HR] = 2.68; 95 % CI, 1.16-6.15; P = 0.020) in multivariable analysis. Patients with a higher TLR had significantly worse OS than patients with a lower TLR (5-year overall survival, 61 % vs. 79.4 %; P = 0.006). In the TACE cohort, the Model for End-Stage Liver Disease (MELD) score (≥8) was a significant independent prognostic factor for OS (HR = 3.34; 95 % CI, 1.49-7.48; P = 0.003), whereas TLR was not associated with OS. The Kaplan-Meier curves showed significantly poorer OS in patients with higher MELD scores (≥8) than in those with lower MELD scores (5-year survival rate, 33.1 % vs. 79.6 %; P < 0.001). Conclusions: Pretreatment TLR measured using FDG PET/CT was an independent prognostic factor for OS in patients with BCLC stage 0 or A HCC undergoing curative treatment. In contrast, underlying liver function appeared to be important in predicting the prognosis of patients undergoing TACE. [ABSTRACT FROM AUTHOR]

The purposes of this study were to optimize a proton computed tomography system (pCT) for proton range verification and to confirm the pCT image reconstruction algorithm based on projection images generated with optimized parameters. For this purpose, we developed a new pCT scanner using the Geometry and Tracking (GEANT) 4.9.6 simulation toolkit. GEANT4 simulations were performed to optimize the geometric parameters representing the detector thickness and the distance between the detectors for pCT. The system consisted of four silicon strip detectors for particle tracking and a calorimeter to measure the residual energies of the individual protons. The optimized pCT system design was then adjusted to ensure that the solution to a CS-based convex optimization problem would converge to yield the desired pCT images after a reasonable number of iterative corrections. In particular, we used a total variation-based formulation that has been useful in exploiting prior knowledge about the minimal variations of proton attenuation characteristics in the human body. Examinations performed using our CS algorithm showed that high-quality pCT images could be reconstructed using sets of 72 projections within 20 iterations and without any streaks or noise, which can be caused by under-sampling and proton starvation. Moreover, the images yielded by this CS algorithm were found to be of higher quality than those obtained using other reconstruction algorithms. The optimized pCT scanner system demonstrated the potential to perform high-quality pCT during on-line image-guided proton therapy, without increasing the imaging dose, by applying our CS based proton CT reconstruction algorithm. Further, we make our optimized detector system and CS-based proton CT reconstruction algorithm potentially useful in on-line proton therapy. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the appropriateness of follow-up with only non-enhanced CT (NECT) in patients with gastrointestinal cancer. Subjects and Methods: This retrospective study included 323 patients with colorectal and gastric cancer who underwent two consecutive CT examinations (CT1 and CT2), including non-contrast and portal venous phase CT images, with an interval of 1 year. Patients were divided into 2 groups: Group A included patients with no hepatic metastasis on CT1 and with or without newly developed metastasis on CT2 to evaluate the diagnostic performance of NECT for detecting newly developed hepatic metastasis; Group B included patients with known hepatic metastasis both on CT1 and CT2 to evaluate the accuracy of NECT for the assessment of hepatic metastasis based on RECIST criteria (version 1.1). Contrast-enhanced CT (CECT) images were considered as reference standards. Results: Group A included 172 patients (M:F = 107:65; mean age, 62.6 years). Among them, 57 patients had 95 metastases (mean size, 2.2 ± 1.3 cm). Per patient and per lesion sensitivity for diagnosing newly developed hepatic metastasis was 56.1–66.7% and 52.6–56.8%, respectively. In terms of small metastases (<1.5 cm), per lesion sensitivity was significantly decreased to 28.1–34.4% (P < 0.05). Metastasis size measurements were significantly smaller on NECT (P < 0.001) compared with reference standards. In Group B, the accuracy of response evaluation based on RECIST criteria was 65.6–72.2%. Conclusions: NECT showed inadequate diagnostic performances in both detecting newly developed hepatic metastasis and evaluating the response of hepatic metastasis based on RECIST criteria. [ABSTRACT FROM AUTHOR]

Backgrounds & Aims The aim of this study is to evaluate the prognostic significances of not only the initial and the best response during repeated transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC), but if eligible, also the time point of achieving treatment responses. Methods Three hundred and fourteen treatment-naïve patients with well-preserved liver function undergoing TACE were recruited. Treatment responses were assessed using modified Response Evaluation Criteria in Solid Tumors. Overall survival (OS) was analyzed using Kaplan–Meier methods, and Cox regression analysis was performed for multivariate analysis. Results After adjusting other variables, objective response (complete response [CR] and partial response [PR]) as the initial response (adjusted hazard ratio [HR] 0.410) and the best response (adjusted HR 0.335) had independent prognostic significances for OS, respectively (both p <0.001). Objective responders as the initial response had the longest OS, followed by patients who subsequently achieved objective response after at least two sessions and those who did not achieve objective response during treatment course eventually (52.6, 27.0, and 10.8 months, respectively; log-rank test, p <0.001). Likewise, patients with CR as the initial response had the longest OS, followed by those who subsequently achieved CR after at least two sessions and those who achieved PR as the best response (70.2, 40.6, and 23.0 months, respectively; log-rank test, p <0.001). Large (>5 cm) and multiple (⩾4) tumors were independently associated with failure to achieve CR after the initial TACE (both p <0.05). Conclusion Both the initial and the best response predicts OS effectively. However, achievement of treatment response at an early time point is still the most robust predictor for favorable outcomes. [ABSTRACT FROM AUTHOR]

A number of studies have reported the therapeutic potential of low-intensity pulsed ultrasound (LIPUS) for induction of bone repair. This study investigated whether bone regeneration might be enhanced by application of focused LIPUS to selectively stimulate fractured calvarial bone. To accomplish this, bone defects were surgically created in the middle of the skull of rats that were subsequently exposed to focused LIPUS. Bone regeneration was assessed by repeated computed tomography imaging after the operation, as well as histologic analysis with calcein, hematoxylin and eosin and proliferating cell nuclear antigen assay. At 6 wk after surgery, bone formation in the focused LIPUS-treated group improved significantly relative to the control. Interestingly, new bone tissue sprouted from focused LIPUS target points. Histologic analysis after exposure to focused LIPUS revealed that proliferating cells were significantly increased relative to the control. Taken together, these results suggest that focused LIPUS can improve re-ossification through enhancement of cell proliferation in calvarial defect sites. [ABSTRACT FROM AUTHOR]

Objectives: To assess the value of a CT-based abdominal aortic calcification (AAC) score as a surrogate marker for the presence of asymptomatic coronary artery disease (CAD). Methods: The AAC scores of 373 patients without cardiac symptoms who underwent both screening coronary CT angiography and abdominal CT within one year were calculated according to the Agatston method. Logistic regression was used to derive two multivariate models from traditional cardiovascular risk factors, with and without AAC scores, to predict the presence of CAD. The AAC score and the two multivariate models were compared by calculating the area under the receiver operating characteristic curve (AUC) and the net reclassification improvement (NRI). Results: The AAC score alone showed a marginally higher AUC (0.823 vs. 0.767, P = 0.061) and significantly better risk classification (NRI = 0.158, P = 0.048) than the multivariate model without AAC. The multivariate model using traditional factors and AAC did not show a significantly higher AUC (0.832 vs. 0.823, P = 0.616) or NRI (0.073, P = 0.13) than the AAC score alone. The optimal cutoff value of the AAC score for predicting CAD was 1025.8 (sensitivity, 79.5 %; specificity, 75.9 %). Conclusions: AAC scores may serve as a surrogate marker for the presence or absence of asymptomatic CAD. Key Points: • Severe vascular calcification indicates a high probability of coronary artery disease. • Vascular calcification in the abdominal aorta can be quantified by computed tomography. • Abdominal CT could lead to early detection of asymptomatic coronary artery disease. [ABSTRACT FROM AUTHOR]

Background: Although the majority of patients with minimal acute subdural hematomas (aSDHs) can be managed conservatively, some require delayed aSDH evacuation due to hematoma enlargement. This study was designed to determine the risk factors associated with delayed hematoma enlargement leading to surgery in patients with aSDHs who did not initially require surgical intervention. Methods: From 2002 to 2012, 98 patients were treated for nonoperative aSDHs following mild head injury (Glasgow Coma Scale scores of 13-15). The outcome variables were radiographic evidence of SDH enlargement on serially obtained computed tomography (CT) images and later surgical evacuation. Univariate and multivariate analyses were applied to both the demographic and initial radiographic features to identify risk factors for SDH progression and surgery. Results: Overall, 64 patients (65 %) revealed minimal SDH or spontaneous hematoma resolution (conservative group) with conservative management at their last follow-up CT scan. The remaining 34 patients (35 %) received delayed hematoma evacuation (delayed surgery group) a median of 17 days after the head trauma. There were no significant differences between the two groups for baseline characteristics, including age, injury type, degree of brain atrophy, prior history of antithrombotic drugs, and coagulopathy. The presence of cerebral contusions and subarachnoid hemorrhages was more common in the conservative group ( p = 0.003 and p = 0.003, respectively). On multivariate analysis, hematoma volume ( p = 0.01, odds ratio [OR] = 1.094, 95 % confidence interval [CI] = 1.021-1.173) and degree of midline shift ( p = 0.01, OR = 1.433, 95 % CI = 1.088-1.888) on the initial CT scan were independently associated with delayed hematoma evacuation. Conclusions: A critical proportion of patients with minimal aSDHs occurring after mild head injury can progress over several weeks and require hematoma evacuation. Especially patients with a large initial SDH volume and accompanying midline shift require careful monitoring of hematoma progression. [ABSTRACT FROM AUTHOR]

Objective: The prognostic factors that contribute to outcome after navigation-assisted drainage in patients with spontaneous intracerebral hemorrhage (ICH) have not been defined. We compared the characteristics and clinical outcomes of patients with spontaneous ICHs who underwent neuronavigation- assisted hematoma drainage. Methods: Forty-seven patients were enrolled from January 2004 to August 2013. The patients were divided into two groups according to Glasgow Outcome Scale (GOS) scores: the good- (GOS 4-5) and poor-outcome (GOS 1-3) groups. A variety of factors, characteristics, and clinical outcomes were analyzed. Results: Among the 47 patients, 16 and 31 showed good and poor outcomes, respectively. The mortality rate was 4.3%. Patients' ages, horizontal and vertical diameters and volume of the hematoma on the initial brain computed tomography scan, and the initial Glasgow Coma Scale (GCS) scores were significantly different between the two groups (P < 0.05). Ages less than 60 years, smaller horizontal and vertical diameters of the hematoma, less initial hematoma volume, higher initial GCS scores, and the absence of intraventricular hemorrhages were significantly associated with good outcome (P < 0.05). Among these factors, initial hematoma volume was a borderline prognostic factor (odds ratio [OR], 0.951; 95% confidence interval [CI], 0.904-1.001; P = 0.054), whereas initial GCS score was a significant prognostic factor (OR, 2.737; 95% CI, 1.371-5.465; P = 0.004), in the multivariate analysis. Conclusion: Initial GCS score and hematoma volume were important prognostic factors of clinical outcome in patients with spontaneous ICHs who underwent navigation-assisted drainage. Such factors should be carefully considered before patients are treated with navigation-assisted hematoma drainage. [ABSTRACT FROM AUTHOR]

Objective: To compare the accuracy of multidetector computed tomography (MDCT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI) for the detection of intrahepatic tumor recurrence after curative resection of hepatocellular carcinoma (HCC). Materials and methods: Fifty-six patients who underwent MDCT and gadoxetic acid-enhanced MRI for postoperative surveillance after resection of HCC were retrospectively analyzed; 26 patients had a recurrence (36 lesions) and 30 patients did not. Recurrent HCCs were confirmed by histological examinations in two, typical dynamic imaging findings on CT and/or MRI in 28, and by demonstration of growth or tumor staining on angiography on six. Two reviewers graded the confidence for the presence of recurrence on CT and MRI, using a five-point scale. The jackknife free-response receiver operating characteristic method was used to compare diagnostic performance. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results: For 36 recurrent lesions, the figure of merit was significantly higher for MRI than MDCT for detecting recurrence for both reviewers ( p < 0.005 for both reviewers). In lesion-by-lesion analysis, the sensitivity was significantly higher on MRI (100% for reviewer 1 and 97% for reviewer 2) than on MDCT (44.4% and 66.6%) for both reviewers ( p < 0.005 for both reviewers). Also in patient-by-patient analysis, sensitivity was significantly higher on MRI (100% and 96.1%) than on MDCT (57.6% and 76.9%) for both reviewers ( p < 0.05 for both reviewers). Conclusion: Gadoxetic acid-enhanced MRI is superior to MDCT for detecting intrahepatic recurrence after curative resection of HCC. [ABSTRACT FROM AUTHOR]

Background: Currently, proposed nomograms are mainly based on post-operative histopathology. The purpose of this study was to identify preoperative computed tomography (CT) and clinical information that allow prediction of disease-free (DFS) and overall survival (OS) of patients surgically treated for pancreatic head cancer. Methods: A total of 136 patients who underwent curative-intent surgery were retrospectively reviewed. Based on results from multivariate Cox regression analysis, a prediction model was constructed with preoperative CT features and clinical information. Overall performance of the nomogram was calculated by Harrell's C-index. Results: Symptoms at diagnosis, preoperative serum CA 19-9 ≥ 34 U/mL, and four imaging features (necrosis (DFS, P = 0.066; OS, P = 0.002), possible venous invasion (DFS, P = 0.150, OS, P = 0.055), suspected metastatic regional lymph node (DFS, P = 0.001; OS, P = 0.099), and associated pancreatitis or pseudocyst (DFS, P = 0.013; OS, P = 0.041)) were included to build the nomogram. The c-statistics for the discrimination power of the proposed nomogram was 0.6496 for DFS and 0.6746 for OS. Conclusion: A nomogram derived from preoperative CT and clinical information could estimate the risk of recurrence and all-cause death after curative-intent surgery for radiologically resectable pancreatic head cancer. [ABSTRACT FROM AUTHOR]

A correction to the article "Comparison of Diagnostic Performance Between Single- and Multiphasic Contrast-Enhanced Abdominopelvic Computed Tomography in Patients Admitted to the Emergency Department With Abdominal Pain: Potential Radiation Dose Reduction," published in a previous issue of "European Radiology," is presented.