Diagnostic Value of Model-Based Iterative Reconstruction Combined with a Metal Artifact Reduction Algorithm during CT of the Oral Cavity.

BACKGROUND AND PURPOSE: Metal artifacts reduce the quality of CT images and increase the difficulty of interpretation. This study compared the ability of model-based iterative reconstruction and hybrid iterative reconstruction to improve CT image quality in patients with metallic dental artifacts when both techniques were combined with a metal artifact reduction algorithm. MATERIALS AND METHODS: This retrospective clinical study included 40 patients (men, 31; women, 9; mean age, 62.9 ± 12.3 years) with oral and oropharyngeal cancer who had metallic dental fillings or implants and underwent contrast-enhanced ultra-high-resolution CT of the neck. Axial CT images were reconstructed using hybrid iterative reconstruction and model-based iterative reconstruction, and the metal artifact reduction algorithm was applied to all images. Finally, hybrid iterative reconstruction + metal artifact reduction algorithms and model-based iterative reconstruction + metal artifact reduction algorithm data were obtained. In the quantitative analysis, SDs were measured in ROIs over the apex of the tongue (metal artifacts) and nuchal muscle (no metal artifacts) and were used to calculate the metal artifact indexes. In a qualitative analysis, 3 radiologists blinded to the patients' conditions assessed the image-quality scores of metal artifact reduction and structural depictions. RESULTS: Hybrid iterative reconstruction + metal artifact reduction algorithms and model-based iterative reconstruction + metal artifact reduction algorithms yielded significantly different metal artifact indexes of 82.2 and 73.6, respectively (95% CI, 2.6-14.7; P < .01). The latter algorithms resulted in significant reduction in metal artifacts and significantly improved structural depictions(P < .01). CONCLUSIONS: Model-based iterative reconstruction + metal artifact reduction algorithms significantly reduced the artifacts and improved the image quality of structural depictions on neck CT images.

Bone Subtraction Iodine Imaging Using Area Detector CT for Evaluation of Skull Base Invasion by Nasopharyngeal Carcinoma.

BACKGROUND AND PURPOSE: Conventional CT has generally lower detectability of bone marrow invasion than MR imaging due to lower tissue contrast. The purpose of this study was to compare the diagnostic performance of conventional CT alone or in combination with bone subtraction iodine imaging using area detector CT for the evaluation of skull base invasion in patients with nasopharyngeal carcinoma. MATERIALS AND METHODS: Forty-four consecutive patients who underwent contrast-enhanced CT using 320-row area detector CT and contrast-enhanced MR imaging for nasopharyngeal carcinoma staging between April 2012 and November 2017 were enrolled in this retrospective study. Bone subtraction iodine images were generated by subtracting pre- and postcontrast volume scans using a high-resolution deformable registration algorithm. Two blinded observers evaluated skull base invasion at multiple sites (sphenoid body, clivus, bilateral base of the pterygoid process, and petrous bone) using conventional CT images alone or in combination with bone subtraction iodine images. Examination of MR and CT images by an experienced neuroradiologist was the reference standard for evaluating sensitivity, specificity, and area under the receiver operating characteristic curve. RESULTS: Twenty-six patients (59%) showed skull base invasion at 84 sites on the reference standard. Conventional CT plus bone subtraction iodine images showed higher sensitivity (92.9% versus 78.6%, P = .02) and specificity (95.6% versus 86.1%, P = .01) than conventional CT images alone for evaluating skull base invasion. The area under the receiver operating characteristic curve for conventional CT plus bone subtraction iodine (0.98) was significantly larger (P < .001) than the area under the receiver operating characteristic curve for conventional CT alone (0.90). CONCLUSIONS: Conventional CT plus bone subtraction iodine performs more closely to the accuracy of combining CT and MR imaging compared with conventional CT alone.

VALIDATION OF MONTE CARLO DOSE CALCULATION FOR PAEDIATRIC CT EXAMINATIONS USING TUBE CURRENT MODULATION BASED ON IN-PHANTOM DOSIMETRY.

The aim of this study is to estimate tube current modulation (TCM) profiles in paediatric computed tomography (CT) examinations with a TCM scheme (Volume-EC) and evaluate the estimation accuracy of TCM profiles. Another aim is to validate organ doses calculated using Monte Carlo-based CT dosimetry software and estimated TCM profiles by comparing them with those measured using 5-year-old and 10-year-old anthropomorphic phantoms and radio-photoluminescence glass dosemeters. Dose calculations were performed by inputting detailed descriptions of a CT scanner, scan parameters and CT images of the phantoms into the software. Organ doses were evaluated from the calculated dose distribution images. Average relative differences (RDs) between the estimated and actual TCM profiles ranged from -3.6 to 5.6%. RDs between the calculated and measured organ doses ranged from -4.2 to 13.0% and -18.1 to 4.9% for 5-year-old and 10-year-old phantoms, respectively. These results validate dose calculations for paediatric CT scans using TCM.

Comparison of MR Imaging and Dual-Energy CT for the Evaluation of Cartilage Invasion by Laryngeal and Hypopharyngeal Squamous Cell Carcinoma.

BACKGROUND AND PURPOSE: Dual-energy CT can distinguish iodine-enhanced tumors from nonossified cartilage and has been investigated for evaluating cartilage invasion in patients with laryngeal and hypopharyngeal squamous cell carcinomas. In this study, we compared the diagnostic accuracy of MR imaging and of a combination of weighted-average and iodine overlay dual-energy CT images in detecting cartilage invasion by laryngeal and hypopharyngeal squamous cell carcinomas, in particular thyroid cartilage invasion. MATERIALS AND METHODS: Fifty-five consecutive patients who underwent 3T MR imaging and 128-slice dual-energy CT for preoperative initial staging of laryngeal or hypopharyngeal squamous cell carcinomas were included. Two blinded observers evaluated laryngeal cartilage invasion on MR imaging and dual-energy CT using a combination of weighted-average and iodine-overlay images. Pathologic findings of surgically resected specimens were used as the reference standard for evaluating sensitivity, specificity, and the areas under the receiver operating characteristic curve of both modalities for cartilage invasion by each type of cartilage and for all cartilages together. Sensitivity and specificity were compared using the McNemar test and generalized linear mixed models. RESULTS: Dual-energy CT showed higher specificity than MR imaging for diagnosing all cartilage together (84% for MR imaging versus 98% for dual-energy CT, P < .004) and for thyroid cartilage (64% versus 100%, P < .001), with a similar average area under the curve (0.94 versus 0.95, P = .70). The sensitivity did not differ significantly for all cartilages together (97% versus 81%, P = .16) and for thyroid cartilage (100% versus 89%, P = .50), though there was a trend toward increased sensitivity with MR imaging. CONCLUSIONS: Dual-energy CT showed higher specificity and acceptable sensitivity in diagnosing laryngeal cartilage invasion compared with MR imaging.

Nationwide investigation of Shiga toxin-producing Escherichia coli among cattle in Japan revealed the risk factors and potentially virulent subgroups.

A nationwide study of Shiga toxin-producing Escherichia coli (STEC) was performed to determine the prevalence, characteristics and risk factors for fecal shedding of STEC among cattle in Japan. Information on rearing practices was also collected to identify risk factors for fecal shedding of STEC. STEC was isolated from 24·1% of samples (133/551) collected from 59·1% of farms (65/110). Bayesian clustering using the virulence marker profiles of the isolates subdivided the isolates into four genetically distinct groups, two of which corresponded to eae- or saa-positive STEC, which can cause severe disease in human. Both STEC groups exhibited characteristic phylogeny and virulence marker profiles. It is noteworthy that the tellurite resistance gene was not detected in all saa-positive STEC isolates, suggesting that the standard isolation method using tellurite might lead to an underestimation of the prevalence of saa-positive STEC. A multivariate logistic regression model using epidemiological information revealed a significantly (P < 0·01) high odds ratio on STEC fecal shedding in tie-stall housing and a low odds ratio in flat feed box and mechanical ventilation. Information on isolate characteristics of the two major pathotypes and risk factors in rearing practices will facilitate the development of preventative measures for STEC fecal shedding from cattle.

Organ Dose Evaluations Based on Monte Carlo Simulation for CT Examinations Using Tube Current Modulation.

The aims of this study were to estimate tube current values for each X-ray projection angle used in adult chest computed tomography (CT) and abdomen-pelvis CT examinations with tube current modulation (TCM) and to validate organ doses determined using Monte Carlo (MC) simulations through comparisons with the doses measured using in-phantom dosimetry. For dose simulations, dose distribution images were obtained by inputting the geometry of a CT scanner, scan parameters including estimated TCM curves and CT images of an adult anthropomorphic phantom into MC simulation software. Organ doses were then determined from the dose distribution images. For dose measurements, organ doses were evaluated using radio-photoluminescence glass dosemeters located at various organ positions within the phantom. Relative differences between the simulated and measured organ doses were -2.5 to 11.0% and -1.5 to 10.5% for organs in chest and abdomen-pelvis CT scan ranges, respectively. Thus, the simulated and measured doses agreed well.

Distribution of extended-spectrum cephalosporin resistance determinants in Salmonella enterica and Escherichia coli isolated from broilers in southern Japan.

This study was conducted to investigate the distribution and diversity of extended-spectrum cephalosporin (ESC) resistance determinants in Salmonella enterica and Escherichia coli obtained from the same cecal samples and to provide evidence of transmission of the resistance determinants among these bacteria in broiler farms in southern Japan. Salmonella enterica and E. coli were characterized by serotyping and multilocus sequence typing, respectively. An antimicrobial susceptibility test, plasmid analysis, and identification and localization of resistance genes were performed to determine the relatedness of ESC resistance determinants among the isolates. Of 48 flocks examined, 14 had S. enterica. In total, 57 S. enterica isolates were obtained, 45 of which showed ESC resistance. Extended-spectrum cephalosporin-resistant E. coli were also obtained from all of these ESC-resistant Salmonella-positive samples. ß-Lactamase genes, blaTEM-52 (38 isolates), blaCTX-M-14 (1 isolate), and blaCMY-2 (6 isolates), were carried by conjugative untypable or IncP plasmids detected in the S. enterica serovars Infantis and Manhattan. The ß-lactamase genes blaCTX-M-14 (3 isolates), blaCTX-M-15 (3 isolates), blaSHV-2 (1 isolate), blaSHV-12 (2 isolates), and blaCMY-2 (32 isolates) associated with IncI1-Iγ, IncFIB, IncFIC, IncK, IncB/O, and IncY plasmids were detected in E. coli co-isolates. Restriction mapping revealed similar plasmids in Salmonella Infantis and Salmonella Manhattan and in different sequence types of E. coli. Intraspecies transmission of plasmids was suggested within S. enterica and E. coli populations, whereas interspecies transmission was not observed. This study highlights the importance of plasmids as carriers of ESC resistance determinants.

Analysis of matrix metalloproteinase (MMP-8 and MMP-2) activity in gingival crevicular fluid from children with Down's syndrome.

BACKGROUND AND OBJECTIVE: High levels of colonization by periodontopathic bacteria and a high prevalence of chronic inflammatory periodontal disease have been reported in children with Down's syndrome. Matrix metalloproteinases (MMPs) are mediators of extracellular matrix degradation and remodelling, and are deeply involved in the course of periodontal disease. To clarify the relationship between Down's syndrome and periodontitis, we investigated levels of MMP-2 and MMP-8 in gingival crevicular fluid (GCF) and detection of periodontopathic bacteria from subgingival plaque. MATERIAL AND METHODS: Samples of GCF and plaque were isolated from central incisors. Levels of MMPs were evaluated by enzyme-linked immunosorbent assay, and periodontopathic bacteria were detected by polymerase chain reaction. RESULTS: Levels of MMP-2 and MMP-8 in Down's syndrome patients were higher than those in healthy control subjects. In the Down's syndrome group, increases in these MMPs were observed in GCF from patients with an oral hygiene index score of < 2 and in GCF from sites that were negative for bleeding on probing. The detection rate of periodontopathic bacteria in Down's syndrome patients was higher than that in the control subjects. Matrix metalloproteinase-2 levels in sites harbouring Porphyromonas gingivalis or Aggregatibacter (Actinobacillus) actinomycetemcomitans were lower than in those without these microorganisms. CONCLUSION: These results suggest an increase in MMP-2 and MMP-8 in Down's syndrome patients, regardless of whether inflammation of periodontal tissue is present or not.

Colonization pattern of periodontal bacteria in Japanese children and their mothers.

BACKGROUND AND OBJECTIVE: The purpose of this study was to determine the time of infection by anaerobic gram-negative rods associated with periodontal disease, and to clarify their transmission from mother to child. MATERIAL AND METHODS: Seventy-eight Japanese children (including 10 siblings), aged from 3 to 9 years, and 68 mothers, were enrolled in this study. Colonization by 11 periodontal bacterial species was determined using polymerase chain reaction amplification of samples of subgingival plaque obtained from the children and their mothers. RESULTS: The detection rates of Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola increased in children after the age of 6 years. We found a high consistency in colonization by P. gingivalis, T. denticola, Prevotella intermedia and Prevotella nigrescens in 9 of the 10 siblings. The average number of bacterial species in plaque samples harboring Fusobacterium nucleatum and/or Fusobacterium periodonticum was significantly greater than in those without, in both children and mothers. Kappa statistical analysis revealed that the detection of Capnocytophaga gingivalis, Capnocytophaga ochracea, Campylobacter rectus and T. denticola in children was consistent with that in the mother. CONCLUSION: Periodontal bacterial colonization in Japanese children increased with age and was associated with F. nucleatum and/or periodonticum, and the bacterial flora in children was similar to that in their mothers.

Solitary pulmonary granuloma caused by Mycobacterium avium-intracellulare complex.

OBJECTIVES: To analyse the clinical features and high resolution computed tomography (HRCT) findings of solitary pulmonary granulomas caused by the Mycobacterium avium-intracellulare (MAI) complex. METHODS: We retrospectively analysed a series of 73 consecutive patients with solitary pulmonary granuloma and negative sputum smear and culture results, in whom the diagnosis was established by histological examination of specimens obtained by partial pulmonary resection or lobectomy. We compared the clinical features and HRCT findings of the solitary pulmonary granulomas definitively diagnosed to be caused by the MAI complex with those of granulomas of other causes by univariate and multivariate analyses. RESULTS: In this study series of 24 patients with solitary pulmonary granuloma, the aetiological agent was established as being the MAI complex. According to the results of the multivariate analysis, 'female sex', 'pleural indentation' and 'lobulation' on the HRCT images were significantly associated with solitary pulmonary granuloma caused by the MAI complex. CONCLUSION: This study demonstrated several characteristics of solitary pulmonary granulomas caused by the MAI complex, and suggested that it might be a subtype of pulmonary MAI complex infection without the typical radiographic features of the infection.

Diagnostic accuracy of CT-guided percutaneous cutting needle biopsy for thymic tumours.

AIM: To determine the diagnostic accuracy of computed tomography (CT)-guided percutaneous cutting needle biopsy (PCNB) for thymic tumours in accordance with the World Health Organization (WHO) classification. MATERIAL AND METHODS: We retrospectively analysed a consecutive series of 138 cases in which CT-guided PCNB had been performed for an anterior mediastinal tumour. Its sensitivity and specificity for thymic epithelial tumours were evaluated, and the concordance between the histopathological diagnosis according to the WHO classification of thymic tumours based on PCNB and the diagnosis is based on the surgical specimens was assessed by Kappa statistic. RESULTS: The diagnostic sensitivity and specificity of CT-guided PCNB for thymic tumours were 93.3 and 100%, respectively. The overall concordance between the diagnosis according to the WHO classification established by PCNB specimen and by the surgical specimen was 79.4% (weighted kappa=0.79). CONCLUSION: CT-guided PCNB is a reliable method of diagnosing thymic tumours, and there was good concordance for the WHO classification between the diagnosis based on CT-guided PCNB specimen and that based on the surgical specimen.

[Neoadjuvant chemotherapy for advanced epithelial ovarian cancer].

Primary surgical cytoreduction followed by paclitaxel/carboplatin combination chemotherapy currently is the treatment of choice for advanced epithelial ovarian cancer. Aggressive surgery is widely accepted as a valid approach to initial cytoreduction of stage III disease, but suboptimal residual disease following primary surgical resection is one of the most important adverse prognostic factors in these patients. Neoadjuvant chemotherapy has been proposed as an alternative approach to conventional surgery for initial management of bulky ovarian cancer, with the goal of improving surgical quality. General acceptance of neoadjuvant chemotherapy as an alternative to primary surgery for patients who are not ideal surgical candidates remains limited, because equivalent or superior survival has not yet been demonstrated in a prospective randomized study. A large-scale, prospective, randomized study is being conducted by the European Organization for Research and Treatment of Cancer (EORTC) Gynecologic Cancer Cooperative Group and Gynecologic Oncology Group (GOG) to compare outcomes (overall and progression-free survival, quality of life, treatment complications) of neoadjuvant chemotherapy/interval debulking surgery versus primary cytoreductive surgery/adjuvant chemotherapy in patients with advanced epithelial ovarian carcinoma.

[Adjuvant GM-CSF cytokine gene therapy for breast cancer].

UNLABELLED: The aim of this study was to examine the enhancement of antitumor immunity of irradiated granulocyte macrophage-colony-stimulating factor (GM-CSF) gene-transduced mouse breast cancer cells. METHODS: BALBMC mouse were vaccinated subcutaneously with saline or irradiated mouse breast cancer cells, BALBMC (1 x 10(6)/mouse), infected or not infected with recombinant adenovirus harboring GM-CSF gene on day-7. Mice were injected with parental cells (1 x 10(5)/mouse) on day 0. RESULTS: No mice vaccinated with irradiated GM-CSF producing BALBMC cells developed a tumor during the observation period of up to 16 weeks, whereas 100% of mice injected with saline developed a tumor. CONCLUSION: Our study demonstrates the feasibility of this immunotherapeutic approach as a novel adjuvant cancer therapy after surgery for breast cancer.

Phase 1 clinical trial of irradiated autologous melanoma cells adenovirally transduced with human GM-CSF gene.

The objective of this study was to determine the safety and antitumor activity of an autologous GM-CSF-secreting melanoma cell vaccine that was engineered ex vivo with recombinant replication-incompetent adenovirus harboring a human GM-CSF gene (Adv/hGM-CSF). Melanoma samples were surgically obtained from 30 patients (15 female and 15 male, ages ranging from 23 to 87) and were processed for vaccine preparation. Due to stringent eligibility criteria, 9 out of 30 patients were enrolled in the phase 1 clinical trial (FDA IND7677). Melanoma cell lines established from surgical specimens of 9 patients were transduced with Adv/hGM-CSF (MOI of 100) and subsequently irradiated at 35 Gy. These cell lines secreted human GM-CSF in vitro at an average rate of 80-424 ng/10(6) cells/24 h. All patients were intradermally and subcutaneously injected at several sites with irradiated autologous melanoma cells (2x10(6)-1x10(7) in 300 microl saline), 2-10 times, at intervals of 4-8 weeks. None of the patients vaccinated showed any serious adverse systemic response. Three patients (nos.1, 6 and 7) demonstrated local reaction (erythema) to the vaccination. Tumor-specific CTL assays performed in the absence of K562 cells showed that the levels of CTLs in peripheral blood of 5 patients increased following vaccination, whereas those in one patient declined. Levels of CTLs assayed in the presence of K562 cells were considerably lower than those assayed in the absence of K562 cells, but were also found to increase following vaccination in the peripheral blood of 6 patients. A patient who had been vaccinated 10 times (patient 1) responded to the vaccination by apparent reduction in size of metastatic tumor in the lung. Immunohistochemical examination of the vaccination sites of patient 1, biopsied after the 3rd and 4th vaccination. showed that the vaccination sites responded with infiltration of inflammatory cells, such as T cells (CD3+, CD8+), macrophages and dendritic cells (CD83+), for a period up to about 8 days. These data suggest that repeated vaccinations with irradiated autologous GM-CSF-producing tumor cells were well tolerated by patients and led to the activation of an antitumor immune response in some patients.

Pulmonary amyloidosis diagnosed by CT-guided transbronchial biopsy: a case report.

During a medical check-up, a nodular shadow was detected by chest X-ray in the right lower lung field of a 59-year-old man. On computed tomography (CT), the nodular lesion had a relatively well-defined, irregular margin. A fluoroscopy-guided bronchoscopic biopsy did not uncover any malignancy. Specimens from a subsequent CT-guided bronchoscopic biopsy revealed a pulmonary amyloid deposit. As a rule, it is difficult to exclude malignancy or confirm benign disease in cases of truly benign lesions, particularly if the lesions are difficult to biopsy. Amyloidosis is one of such conditions and requires reliable diagnostic methods to avoid unnecessary surgical resection. From our experience, we consider CT-guided bronchoscopic biopsy to be a safe and accurate procedure, even when applied to truly benign lesions.

Primary synovial sarcoma of the lung: a case report confirmed by molecular detection of SYT-SSX fusion gene transcripts.

We report a rare case of primary synovial sarcoma of the lung. The patient was a 49-year-old woman who presented with a well-defined oval-shaped mass in the left upper lobe on a chest radiograph. A malignant pulmonary tumor was suspected and consequently a left upper lobectomy was performed. Grossly, the tumor measured 5 x 4 cm, was whitish-yellow in color and soft in consistency. Histologically, the tumor showed a dense proliferation of short spindle cells, partly arranged in interlacing fascicles. In some areas a hemangiopericytoma-like pattern, stromal myxoid change and necrosis of various sizes were noted. Numerous mitotic figures were also seen. Immunohistochemically, the tumor cells were positive for epithelial markers such as cytokeratin and epithelial membrane antigen. As these features suggested a monophasic fibrous type of synovial sarcoma, we examined for the presence of SYT-SSXfusion gene transcripts using RNA samples from the frozen tumor tissue. A reverse transcription polymerase chain reaction amplified a single 583-base pair fragment characteristic of synovial sarcoma. As no other tumorous lesions were found during a follow-up period of 1 year, primary synovial sarcoma of the lung was our final diagnosis. This tumor should be considered in the differential diagnosis of round to short spindle cell tumors arising in the lung.

Identification of shiga toxin-producing Escherichia coli possessing insertionally inactivated Shiga toxin gene.

We have investigated the Shiga toxin genes of Shiga toxin-producing Escherichia coli (STEC) strains, using polymerase chain reaction (PCR) amplifying the full lengths of these genes. As a result, we found the Shiga toxin 2 gene which was insertionally inactivated by an insertion sequence (IS). This IS element was identical to IS1203v which has been also found in inactivated Shiga toxin 2 genes, and was inserted at the same site as in the previous paper. On the other hand, both Shiga toxin 2 genes were different (98.3% identity). These suggested that IS1203v independently inserted into each Shiga toxin 2 genes, and STEC strains possessing the insertionally inactivated Shiga toxin genes are most likely to have a wide distribution. Amplification of the full length of the Shiga toxin gene is one of the effective methods to detect the gene no matter where the IS element is included, i.e., the insertion can be reflected in the size of amplicon.

Invasive and noninvasive thymoma: distinctive CT features.

PURPOSE: The purpose of this work was to evaluate the CT features of thymoma and to determine the most helpful findings in differentiating invasive from noninvasive thymoma. METHOD: The CT scans from 27 patients with invasive thymoma and 23 with noninvasive thymoma were independently assessed by two observers without knowledge of their invasiveness. The presence and distribution of various CT findings were independently analyzed. RESULTS: Invasive thymomas were more likely to have lobulated (16/27, 59%) or irregular (6/27, 22%) contours than noninvasive thymomas (8/23, 35% and 1.5/23, 6%, respectively) (p < 0.05). Invasive thymomas had a higher prevalence of low attenuation areas within the tumor (16/27, 60%) than noninvasive thymomas (5/23, 22%) (p < 0.001) as well as foci of calcification (14.5/27, 54% vs. 6/23, 26%; p < 0.01). CONCLUSION: The presence of lobulated or irregular contour, areas of low attenuation, and multifocal calcification is suggestive of invasive thymoma.