Intramedullary Spinal Cord Malakoplakia Mimicking Malignant Neoplasm on 18F-FDG PET/CT.

ABSTRACT: We report a rare case of intramedullary spinal cord malakoplakia mimicking malignancy on 18F-FDG PET/CT. A 61-year-old man underwent a contrast-enhanced spinal cord MRI to evaluate 1 week of progressive left-sided weakness. Spinal cord MRI showed a 1.3-cm enhancing intramedullary cervical spinal cord mass at C5 level with cord edema. Subsequently, 18F-FDG PET/CT was performed for evaluation. The images showed a well-circumscribed hypermetabolic mass in the spinal cord; no lesions were suggestive of malignancy or metastasis. A subtotal tumor excision was performed; histopathological examination revealed malakoplakia. This emphasizes the significance of histopathological evaluation and the importance of diagnostic confirmation.

Effects of Seed Endophytic Bacteria on Life History and Reproductive Traits in a Cosmopolitan Weed, Capsella bursa-pastoris.

Diverse bacteria inhabit plant seeds, and at least some of them can enhance plant performance at the early developmental stage. However, it is still inconclusive whether seed bacteria can influence post-germination traits and their contribution to plant fitness. To explore the evolutionary and ecological consequences of seed endophytic bacteria, we isolated four bacterial strains from the seeds of an annual weedy plant species, Capsella bursa-pastoris, and conducted a common garden experiment using seeds inoculated by isolated bacteria. Seeds infected by bacteria tended to germinate in spring rather than in autumn. Bacterial treatment also altered the expression of plant life history and reproductive traits, including flowering dates, rosette diameter at bolting, number of inflorescences, and fruit production. The results of the path analyses suggested that such effects of bacterial treatments were due to bacterial inoculation as well as germination delayed until spring. Spring germinants with bacterial infection showed a weaker association between post-germination traits and relative fitness than those without bacterial infection. These results suggest that seed bacteria likely affect the expression of post-germination traits directly or indirectly by delaying the germination season. An altered contribution of plant traits to relative fitness implies the influence of seed bacteria on the strength of natural selection.

Genotype-Specific Plastic Responses to Seed Bacteria under Drought Stress in Lactuca serriola.

Recent studies have demonstrated that seed-borne bacteria can enhance the performance of invasive plants in novel introduced habitats with environmental stresses. The effect of this plant-bacteria interaction may vary with plant species or even genotype; however, the genotype-dependent effects of seed bacteria have rarely been assessed. In this study, we examined the effects of bacterial strains isolated from seeds on the genotypes of an invasive xerophytic plant, Lactuca serriola. Plant genotypes were grown under drought conditions, and their plastic responses to bacterial infections were evaluated. Some genotypes produced more biomass, whereas others produced less biomass in response to infection with the same bacterial strain. Notably, the quantity of root-adhering soil depended on the bacterial treatment and plant genotypes and was positively correlated with the plastic responses of plant performance. Because tested bacteria could colonize the plant rhizosphere, bacterial infection appears to induce the differential formation of soil rhizosheaths among plant genotypes, consequently affecting the maintenance of soil water content under drought conditions. Given that drought tolerance is a critical attribute for the invasive success of L. serriola, these results imply that bacterial symbionts can facilitate the establishment of alien plant species, but their effects are likely genotype-specific.

Variation of the seed endophytic bacteria among plant populations and their plant growth-promoting activities in a wild mustard plant species, Capsella bursa-pastoris.

Recent studies have revealed that some bacteria can inhabit plant seeds, and they are likely founders of the bacterial community in the rhizosphere of or inside plants at the early developmental stage. Given that the seedling establishment is a critical fitness component of weedy plant species, the effects of seed endophytic bacteria (SEB) on the seedling performance are of particular interest in weed ecology. Here, we characterized the SEB in natural populations of Capsella bursa-pastoris, a model species of weed ecology. The composition of endophytic bacterial community was evaluated using deep sequencing of a 16S rDNA gene fragment. Additionally, we isolated bacterial strains from seeds and examined their plant growth-promoting traits. Actinobacteria, Firmicutes, Alpha-, and Gammaproteobacteria were major bacterial phyla inside seeds. C. bursa-pastoris natural populations exhibited variable seed microbiome such that the proportion of Actinobacteria and Alphaproteobacteria differed among populations, and 60 out of 82 OTUs occurred only in a single population. Thirteen cultivable bacterial species in six genera (Bacillus, Rhodococcus, Streptomyces, Staphylococcus, Paenibacillus, Pseudomonas) were isolated, and none of them except Staphylococcus haemolyticus were previously reported as seed endophytes. Eight isolates exhibited plant growth-promoting traits like phosphate solubilization activity, indole-3-acetic acid, or siderophore production. Despite the differences in the bacterial communities among plant populations, at least one isolated strain from each population stimulated shoot growth of either C. bursa-pastoris or its close relative A. thaliana when grown with plants in the same media. These results suggest that a weedy plant species, C. bursa-pastoris, contains bacterial endophytes inside their seeds, stimulating seedling growth and thereby potentially affecting seedling establishment.

Predicting the Recurrence of Hepatocellular Carcinoma after Primary Living Donor Liver Transplantation Using Metabolic Parameters Obtained from 18F-FDG PET/CT.

This study evaluated the prognostic value of metabolic parameters based on the standardized uptake value (SUV) normalized by total body weight (bwSUV) and by lean body mass (SUL) measured on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for predicting tumor recurrence after primary living donor liver transplantation (LDLT) in patients with hepatocellular carcinoma (HCC) without transplantation locoregional therapy. This retrospective study enrolled 49 patients with HCC. The maximum tumor bwSUV (T-bwSUVmax) and SUL (T-SULmax) were measured on PET. The maximum bwSUV (L-bwSUVmax), mean bwSUV (L-bwSUVmean), maximum SUL (L-SULmax), and mean SUL (L-SULmean) were measured in the liver. All metabolic parameters were evaluated using survival analyses and compared to clinicopathological factors. Tumor recurrence occurred in 16/49 patients. Kaplan-Meier analysis revealed that all metabolic parameters were significant (p < 0.05). Univariate analysis revealed that prothrombin-induced by vitamin K absence or antagonist-II; T-stage; tumor number; tumor size; microvascular invasion; the Milan criteria, University of California, San Francisco (UCSF), and up-to-seven criteria; T-bwSUVmax/L-bwSUVmean; T-SULmax; T-SULmax/L-SULmax; and T-SULmax/L-SULmean were significant predictors. Multivariate analysis revealed that the T-SULmax/L-SULmean (hazard ratio = 115.6; p = 0.001; cut-off, 1.81) and UCSF criteria (hazard ratio = 172.1; p = 0.010) were independent predictors of tumor recurrence. SUL-based metabolic parameters, especially T-SULmax/L-SULmean, were significant, independent predictors of HCC recurrence post-LDLT.

Invasive Lactuca serriola seeds contain endophytic bacteria that contribute to drought tolerance.

The mutualistic relationship between alien plant species and microorganisms is proposed to facilitate or hinder invasive success, depending on whether plants can form novel associations with microorganisms in the introduced habitats. However, this hypothesis has not considered seed endophytes that would move together with plant propagules. Little information is available on the seed endophytic bacteria of invasive species and their effects on plant performance. We isolated the seed endophytic bacteria of a xerophytic invasive plant, Lactuca serriola, and examined their plant growth-promoting traits. In addition, we assessed whether these seed endophytes contributed to plant drought tolerance. Forty-two bacterial species were isolated from seeds, and all of them exhibited at least one plant growth-promoting trait. Kosakonia cowanii occurred in all four tested plant populations and produced a high concentration of exopolysaccharides in media with a highly negative water potential. Notably, applying K. cowanii GG1 to Arabidopsis thaliana stimulated plant growth under drought conditions. It also reduced soil water loss under drought conditions, suggesting bacterial production of exopolysaccharides might contribute to the maintenance of soil water content. These results imply that invasive plants can disperse along with beneficial bacterial symbionts, which potentially improve plant fitness and help to establish alien plant species.

Development of a deep neural network for generating synthetic dual-energy chest x-ray images with single x-ray exposure.

Dual-energy chest radiography (DECR) is a medical imaging technology that can improve diagnostic accuracy. This technique can decompose single-energy chest radiography (SECR) images into separate bone- and soft tissue-only images. This can, however, double the radiation exposure to the patient. To address this limitation, we developed an algorithm for the synthesis of DECR from a SECR through deep learning. To predict high resolution images, we developed a novel deep learning architecture by modifying a conventional U-net to take advantage of the high frequency-dominant information that propagates from the encoding part to the decoding part. In addition, we used the anticorrelated relationship (ACR) of DECR for improving the quality of the predicted images. For training data, 300 pairs of SECR and their corresponding DECR images were used. To test the trained model, 50 DECR images from Yonsei University Severance Hospital and 662 publicly accessible SECRs were used. To evaluate the performance of the proposed method, we compared DECR and predicted images using a structural similarity approach (SSIM). In addition, we quantitatively evaluated image quality calculating the modulation transfer function and coefficient of variation. The proposed model selectively predicted the bone- and soft tissue-only CR images from an SECR image. The strategy for improving the spatial resolution by ACR was effective. Quantitative evaluation showed that the proposed method with ACR showed relatively high SSIM (over 0.85). In addition, predicted images with the proposed ACR model achieved better image quality measures than those of U-net. In conclusion, the proposed method can obtain high-quality bone- and soft tissue-only CR images without the need for additional hardware for double x-ray exposures in clinical practice.

Colonic Parasitic Infection Mimicking Peritoneal Seeding on 18F-FDG PET/CT.

A 77-year-old man with anorexia and weight loss for 6 months received a diagnosis of gastric cancer by endoscopy and referred for F-FDG PET/CT for initial staging. F-FDG PET/CT showed multiple foci of increased FDG uptake with diffuse wall thickening and multiple diverticula. The differential diagnoses were peritoneal seeding and multiple diverticulitis. The patient underwent curative total gastrectomy, and the lesion was diagnosed as poorly differentiated adenocarcinoma by histological examination. He underwent anterior resection of the sigmoid colon for exploration. The nodular lesions of the sigmoid colon were diagnosed by histopathologic examination as chronic diverticulitis caused by a parasitic infection.

Evaluation of the predictive value of coronary artery calcium score for obstructive coronary artery disease in asymptomatic Korean patients with type 2 diabetes mellitus.

BACKGROUND: Compared with coronary computed tomographic angiography (CCTA), the coronary artery calcium score (CACS) may be limited in predicting adverse cardiovascular events in asymptomatic diabetic patients. METHODS: We evaluated the predictive value of CACS for obstructive coronary plaques (OCPs) assessed by CCTA in 328 consecutive asymptomatic patients with type 2 diabetes mellitus who had an estimated glomerular filtration rate greater than 60 ml/min/1.73 m². RESULTS: In total, 29 (9%) patients had OCPs: calcified or mixed OCPs and noncalcified OCPs were found in 26 (8%) and three (1%) patients, respectively. On the basis of a CACS of 0, 1-10, 11-100, and greater than 100, OCPs were found in 2, 5, 15, and 36% of patients, respectively. On receiver operating characteristic curve analysis, the optimal cutoff CACS for predicting OCPs was found to be 33, with 83% sensitivity and 81% specificity (area under the curve, 0.853; 95% confidence interval, 0.777-0.930; P<0.001). Positive and negative predictive values of a CACS of 33 for OCPs were 30 and 98%, respectively. On multivariate logistic regression analysis, age [odds ratio (OR), 1.09], microalbuminuria (OR, 3.43), current smoking (OR, 3.93), and CACS greater than 33 (OR, 15.85) were found to be independently associated with an increased risk for OCPs (P<0.05, respectively). The predictive significance of CACS greater than 33 for OCPs improved after considering the status of microalbuminuria and current smoking. CONCLUSION: These findings suggest that CACS is an effective gatekeeper for evaluating obstructive coronary artery disease using CCTA in asymptomatic Korean patients with type 2 diabetes mellitus who have near-normal kidney function.

Differential association between obesity and coronary artery disease according to the presence of diabetes in a Korean population.

BACKGROUND: Coronary artery disease (CAD) is a major cardiovascular complication in diabetic patients. Despite the significant association between obesity and diabetes, the majority of the diabetic subjects are not obese in an Asian population. This study evaluated the association between obesity and coronary artery disease (CAD) according to the diabetes status in a Korean population. METHODS: The association between obesity and CAD using the parameters of any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to the presence of diabetes was evaluated in 7,234 Korean adults who underwent multi-detector computed tomography for general health evaluations. Obesity was defined as a body mass index (BMI) ≥25 kg/m(2). RESULTS: The prevalence of obesity was significantly higher in diabetic subjects than in non-diabetic subjects, but the majority of the diabetic subjects were non-obese (48% vs. 37%, p <0.001). The incidence of any plaque (58% vs. 29%), obstructive plaque (20% vs. 6%), and CACS >100 (20% vs. 6%) were significantly higher in diabetic patients than in non-diabetic subjects (p <0.001, respectively). Incidence of any plaque (33% vs. 26%, p <0.001), obstructive plaque (7% vs. 6%, p = 0.014), and CACS >100 (8% vs. 6%, p = 0.002) was significantly higher in non-diabetic subjects with obesity than in those without obesity, but the incidence of all coronary parameters was not different in diabetic subjects according to the obesity status. After adjusting for confounding risk factors including age, gender, hypertension, dyslipidemia, current smoking, and mild renal dysfunction, obesity was independently associated with increased risks of any plaque (OR 1.14) and CACS >100 (OR 1.31) only in non-diabetic subjects (p <0.05, respectively). Multiple logistic regression models revealed that diabetes was independently associated with all coronary parameters. CONCLUSION: Despite a significantly higher prevalence of obesity in diabetic subjects than in non-diabetic subjects, obesity is associated with the presence of any plaque and severe coronary calcification only in subjects without established diabetes among Korean population.

Differential association between metabolic syndrome and coronary artery disease evaluated with cardiac computed tomography according to the presence of diabetes in a symptomatic Korean population.

BACKGROUND: Metabolic syndrome (MetS) is associated with increased risks of diabetes and coronary artery disease (CAD). Despite the controversial inclusion of established diabetes in MetS, the association between MetS and CAD according to diabetes status has not been elucidated in the Asian population. METHODS: We evaluated the association between MetS and CAD using the parameters including any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to diabetes status in 2,869 symptomatic Korean subjects who underwent cardiac computed tomographic angiography. RESULTS: The prevalence of MetS was significantly higher in the diabetic subjects than in the non-diabetic subjects (69% vs. 34%, P <0.001). The incidence of any plaque (64% vs. 43%, P <0.001), obstructive plaque (26% vs. 13%, P = 0.006), and CACS >100 (23% vs. 12%, P = 0.012) was significantly higher in diabetic subjects than in non-diabetic subjects. Among the MetS components, decreased high-density lipoprotein level was significantly associated with any plaque (odds ratio [OR] 1.35), obstructive plaque (OR 1.55), and CACS >100 (OR 1.57) in the non-diabetic subjects (P <0.01, respectively). However, none of the MetS components were associated with all the parameters in the diabetic subjects. Multivariate regression analysis revealed that MetS and the number of MetS components (MetSN) were independently associated with any plaque (MetS: OR 1.55, P <0.001; MetSN: OR 1.22, P <0.001), obstructive plaque (MetS: OR 1.52, P = 0.003; MetSN: OR 1.25, P <0.001), and CACS >100 (MetS: OR 1.46, P = 0.015; MetSN: OR 1.21, P = 0.004) only in the non-diabetic subjects, respectively. CONCLUSIONS: MetS was independently associated with the presence and severity of CAD only in the non-diabetic subjects among the symptomatic Korean population.

Usefulness of SPECT/CT for equivocal findings on (131)I whole-body scan in a patient with differentiated papillary thyroid cancer.

A 42-year-old female patient who underwent right central compartment node dissection owing to recurrence of differentiated papillary thyroid carcinoma received 150 mCi of I as an adjuvant therapy. Uptake was observed at the thyroid bed and right lower neck, suggesting thyroid remnant tissues and/or lymph node metastasis on a whole-body scan obtained 5 days after I administration. SPECT/CT was performed and the uptake at the right lower neck was finally diagnosed as a lung metastasis. This case illustrates the benefit of SPECT/CT for a patient with equivocal findings on an I planar image.

Rationale and design of the ViCTORY (Validation of an Intracycle CT Motion CORrection Algorithm for Diagnostic AccuracY) trial.

BACKGROUND: Coronary CT angiography (CTA) has emerged as an effective noninvasive method for direct visualization of the coronary arteries, with high diagnostic performance compared with invasive coronary angiography (ICA). However, coronary CTA is prone to artifacts, including coronary motion, which may reduce its diagnostic performance. Intracycle motion compensation algorithms (MCAs) from a combination of software and hardware techniques now allow for correction of coronary motion, but the diagnostic performance of MCAs compared with traditional coronary CTA reconstruction methods remains unexplored. METHODS: ViCTORY (Validation of an Intracycle CT Motion CORrection Algorithm for Diagnostic AccuracY) is a prospective international multicenter trial of 218 patients which is designed to evaluate the performance of MCAs for the diagnosis of anatomically obstructive coronary artery disease (CAD) compared with an ICA reference standard, on a per-patient, per-vessel, and per-segment basis. Patients enrolled into ViCTORY will undergo investigational coronary CTA and clinically indicated ICA and will not receive heart rate-lowering medications before coronary CTA. Coronary CTA images will be reconstructed by conventional standard methods as well as by MCAs. Blinded core laboratory interpretation will be performed for coronary CTA and ICA in an intent-to-diagnose fashion. RESULTS: The primary end point of ViCTORY is the per-patient diagnostic accuracy of MCAs for the diagnosis of anatomically obstructive CAD compared with ICA. Secondary end points will include other per-patient, per-vessel, and per-segment diagnostic performance characteristics, including accuracy, sensitivity, specificity, positive predictive value, and negative predictive value. Other key secondary end points will include diagnostic interpretability, image quality, the upper heart rate threshold of utility of MCAs, and the additive value of MCAs to traditionally reconstructed coronary CTA. CONCLUSION: ViCTORY will determine whether MCAs improve the diagnosis of obstructive CAD in patients undergoing coronary CTA who are not receiving heart rate-lowering medications.

Assessment of tissue characteristics of noncalcified coronary plaques by 64-slice computed tomography in comparison with integrated backscatter intravascular ultrasound.

BACKGROUND: The ability of 64-slice computed tomography (CT) angiography to differentiate plaque types remains unclear. We evaluated whether the density of noncalcified coronary plaques by 64-slice CT angiography correlates with plaque components assessed by integrated backscatter intravascular ultrasound (IB-IVUS). METHODS: Eighty-six patients [stable angina/acute coronary syndrome (ACS) 67/19, mean age 62+/-11 years] who showed significant coronary artery stenosis (> or =50% diameter stenosis) by 64-slice CT angiography underwent coronary angiography and were evaluated using IB-IVUS. RESULTS: A total of 92 noncalcified coronary plaques on CT angiography were evaluated with IB-IVUS. There was a positive correlation between CT density and calcified tissue content (r=0.41, P<0.001). However, the CT density of plaques did not correlate with other tissue components. Patients with ACS showed more lipid (43.1+/-13.2 vs. 35.8+/-13.5, P=0.03) and less soft fibrous tissue (50.5+/-11.7 vs. 56.5+/-12.0, P=0.05) by IB-IVUS than those with stable angina. However, the mean CT density of plaques in ACS was not different from that in stable angina (140.6+/-88.5 vs. 113.1+/-80.9, P=0.19). CONCLUSION: Except for calcified tissue, CT angiography failed to differentiate plaque types of noncalcified tissue. Therefore, the role of 64-slice CT angiography in identifying lipid-rich plaques remains limited.