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.

Abstract P6-17-06: Characterization, monitoring and management of interstitial lung disease in patients with metastatic breast cancer: Analysis of data available from multiple studies of DS-8201a, a HER2-targeted antibody drug conjugate with a topoisomerase I inhibitor payload

Background: Several classes of anti-cancer agents including certain immunotherapies, systemic chemotherapies, and targeted therapies including trastuzumab and T-DM1 increase the risk of interstitial lung disease (ILD) and fatal cases have been reported. For DS-8201a, interim efficacy and safety analyses of available data established a final recommended dose of 5.4 mg/kg IV q3wk in advanced HER2-positive breast cancer (BC). Based on preliminary clinical results, ILD was identified as an important risk for DS-8201a. A robust monitoring and management plan was established across all studies and an international, independent ILD adjudication committee (AC) reviews the cases reported as ILD on an ongoing basis.

Methods: All subjects (sbj) who received ≥1 dose of DS-8201a across 7 ongoing studies were included in this analysis. Reported ILD (standardized MedDRA Query terms) included the terms ILD, pneumonitis, and organizing pneumonia. ILD frequencies were calculated based on investigator's assessment and after adjudication. The analysis of potential risk factors associated with ILD is ongoing.

Results: As of 21 June 2018, 448 sbj received ≥1 dose of DS-8201a across multiple tumor types, including BC. Of the 321 sbj with BC, 173 (53.9%) were from Japan, 103 (32.1%) from the US, and 45 (14.0%) from 6 other countries (Spain, South Korea, Taiwan, Belgium, France, and Italy). These sbj received 1 of 7 doses of DS-8201a (0.8 mg/kg: 3 sbjs, 1.6 mg/kg: 1 sbj, 3.2 mg/kg: 3 sbjs, 5.4 mg/kg: 111 sbjs, 6.4 mg/kg: 178 sbj, 7.4 mg/kg: 20 sbj, 8.0 mg/kg: 5 sbj). Overall, 44 cases of potential ILD were reported by the investigators across all tumor types (44/448, 9.8%; Grade ≥3 10/448, 2.2%). In sbj with BC who received 5.4 mg/kg, any grade and Grade ≥3 investigator-reported ILD were 7.2% (8/111) and 0.9% (1/111), respectively. The ILD AC assessed 30 of 44 cases; 22 were considered drug-related ILD, 4 were ILD but not drug-related, and 4 were found not to be ILD. For adjudicated drug-related ILD cases, the median time to onset was 159 (range; 46-591) days from the time of first dose.

  Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 All Grades All tumors, All doses (N=448)      Investigator-reported20 (4.5)14 (3.1)4 (0.9)1 (0.2)5 (1.1)44 (9.8)Cases adjudicated13840530Adjudicated as drug-related ILD9 (2.0)6 (1.3)3 (0.7)04 (0.9)22 (4.9) BC, All doses (N=321)      Investigator-reported17 (5.3)11 (3.4)3 (0.9)1 (0.3)4 (1.2)36 (11.2)Cases adjudicated11830426Adjudicated as drug-related ILD8 (2.5)6 (1.9)3 (0.9)04 (1.2)21 (6.5) BC, 5.4 mg/kg (N=111)      Investigator-reported4 (3.6)3 (2.7)001 (0.9)8 (7.2)Cases adjudicated120014Adjudicated as drug-related ILD00001 (0.9)1 (0.9)n (%), except where noted

Conclusions: These analyses confirm that ILD is an important identified risk for DS-8201a. Further analyses are ongoing to better understand the potential risk factors associated with the incidence of on-treatment ILD. When ILD is suspected, early diagnosis through appropriate imaging, laboratory tests, and pulmonary consultation as well as prompt management with steroids are recommended.

Citation Format: Powell CA, Camidge DR, Gemma A, Kusumoto M, Baba T, Kuwano K, Bankier A, Kiura K, Tamura K, Modi S, Tsurutani J, Doi T, Iwata H, Krop IE, Zhang L, Jasmeet S, Saito K, Shahidi J, Yver A, Takahashi S. Characterization, monitoring and management of interstitial lung disease in patients with metastatic breast cancer: Analysis of data available from multiple studies of DS-8201a, a HER2-targeted antibody drug conjugate with a topoisomerase I inhibitor payload [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-06.

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.

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. β-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 β-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.

Stage-size relationship in long-term repeated CT screening for lung cancer: Anti-Lung Cancer Association project

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Background: We have investigated the individualized benefit of CT screening as Anti-Lung Cancer Association projects (presented at ASCO 2006–2008). However, there has not been enough information about the relationship of lung cancer stage to tumor size in repeated CT screening. Therefore, we evaluated the stage-size relationship of these asymptomatic lung cancer cases diagnosed by long-term repeated screening with low-dose helical CT. Methods: Among 2,120 participants (mean age 63 years, 87% male, and 83% smoker) at baseline screening, 1,877 underwent semiannually repeated screening from 1993 to 2004. Nineteen (0.90%) prevalence cancers and 57 (0.32%) incidence cancers were detected. Within categories of tumor size, the distribution of pathological stage, histology, lymph node status, and distant metastases was determined. Results: Pathological stage has a strong relationship to tumor size at baseline screening (spearman r = 0.63, p = 0.013) and repeated screening (r = 0.65, p < 0.001). In the analysis of all 76 cases, lymph node status (r = 0.59, p < 0.001) and distant metastases (r = 0.55, p = 0.005) have also a strong relationship to tumor size. The percentages of cases with no metastases (N0M0) were 100% (0/21), 89% (17/19), 62% (8/13), 83% (10/12), 50% (4/8), and 33% (1/3) for the categories 10 mm or less, 11 mm to 15 mm, 16 mm to 20 mm, 21 mm to 30 mm, 31 mm to 40 mm, and 41 mm or greater, respectively. Histology for the categories 15 mm or less was localized bronchioloalveolar carcinoma in 13 cases, adenocarcinoma with mixed subtype in 11 cases, invasive adenocarcinoma in five cases, other non-small cell carcinoma in 10 cases, and small cell carcinoma in one case. Accumulated 10-year hazard ratio of above histology was 2.4, 2.5, 2.6, 4.1, and 0.7. In multivariate analyses, pathological stage was related to only tumor size (standardized regression coefficient beta = 0.59, p < 0.001) whereas histology was related to tumor size (beta = 0.43, p < 0.001) and smoking index (beta = 0.28, p = 0.016). Conclusions: These results provide direct evidence of a stage-size relationship in long-term repeated CT screening for lung cancer. Furthermore, early detection of lung cancer of 15 mm or less in diameter leads to the detection of early-stage (N0M0) lung cancer in repeated CT screening.

No significant financial relationships to disclose.

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.

What we could know from the semiannually repeated screening with low-dose helical CT in a high-risk cohort over 10 years: Update of Anti-Lung Cancer Association project

7568

Background: There have been several randomized trials of low-dose helical CT (LDCT) screening for lung cancer. However, all trials are in progress. Therefore, before they are completed, we summarized what we could know from an update of Anti-Lung Cancer Association project, which was regarded as a longer-term study with LDCT performed at shorter intervals and with a larger number of detected cancers than any other single-armed studies. Methods: Among 2,120 participants, 1,877 (mean age 64 years, 88% male, and 84% smoker) underwent semiannually repeated screening from 1993 to 2004 (median, 3.5 years). We investigated (1) survival of patients with screening detected lung cancers, (2) presence of a stage shift (indicator of a mortality benefit), (3) appropriate duration of repeated screening, (4) identification of high-risk group by age, sex, and smoking, and (5) appropriate screening intervals by high-risk group (6 months or 1 year). Results: (1) The 5- and 10-year survival rates were 84.5% and 84.5%, respectively, in repeated screening group (n = 57) and were 68.7% and 38.1%, respectively, in initial screening group (n = 19) (P = 0.208). (2) Only in invasive adenocarcinoma, both proportion of stage II to IV and tumor size were negatively correlated with duration of repeated screening (r = −0.77, P = 0.007 and r = − 0.60, P = 0.029, respectively). (3) Detection rate of all incidence cancers were positively correlated with duration of repeated screening (r = 0.50, P = 0.020). However, detection rate remained unchanged until 5 years of repeated screening. Moreover, stage shift did not occur until 5 years of repeated screening. (4) Female sex (HR 2.9, P = 0.015) and smoking (HR 2.7, P = 0.046) were demographic risk factors for lung cancer detection at repeated screening. The accumulated 10-year detection rates for female smokers (n = 91), male smokers (n = 1,557), and non-smokers (n = 229) were 15.1%, 6.2%, and 4.3%, respectively (P = 0.002). (5) The estimated relative cancer detection powers of annual screening to semiannual screening were 50% and 57% for female and male smokers with lung cancer, respectively. Conclusions: Semiannually repeated LDCT screening over 5 years might be beneficial to smokers, especially female smokers.

No significant financial relationships to disclose.

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.

Evaluation of radiologic diagnosis in peripheral clinical IA lung cancers—A prospective study for radiological diagnosis of peripheral early lung cancer (JCOG 0201)

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Background: The spread of computed tomography (CT) screening for lung cancer (LC) leads to the increased detection of small sized LC. Performance and accuracy of radiological diagnosis had not been evaluated and indication of limited surgery for CT detected LC remains unknown. Methods: Between Dec/2002 and May/2004, a prospective study was performed. Patients (pts) having peripheral lung adenocarcinoma (AD) of T1N0M0 were eligible. Radiologic findings of LC were evaluated as to ground-glass opacity (GGO) with thin-section CT (TSCT). A radiological non-invasive cancer (NIC) was defined as a tumor having consolidation less than half of the maximum tumor dimension. A pathological NIC, which is future candidate for limited surgery, was defined as a tumor with no lymph node mets, lymphatic, nor vascular invasion. A validity of radiological diagnosis by above criteria was investigated. Primary endpoint is specificity as the proportion of pts with radiologically diagnosed invasive LC in pts with pathologically diagnosed invasive LC. Planned sample size was 450 with precision-base. We expected that lower limit of 95% CI of specificity is over 97%. Results: Totally 811 pts were enrolled onto the study at 31 institutions, including 357 men. Age ranged 27 to 75 (median 61). Primary endpoint was evaluated on central-reviewed 545 AD resected by lobectomy. Specificity and sensitivity for the diagnosis of pathological NIC were 96.4% (161/167 95% CI 92.3% to 98.7%) and 30.4% (115/378 95% CI 25.8% to 35.3%), respectively. As to relationship between radiologic NIC and pathological nodal involvement, specificity and sensitivity for the diagnosis were 98.3% (59/60 95% CI 91.1% to 100%) and 24.7% (120/485 95% CI 21.0% to 28.8%), respectively. Conclusions: Our pre-determined criterion for the specificity was not confirmed, and candidates for limited surgical resection can not be selected based on our criteria. However, radiological diagnosis of node-negative LC with TSCT was well coincide, and the criterion might be used for selecting node negative peripheral LC. A phase II study of limited surgical resection for peripheral LC 2.0 cm or less in size is now planned based on the results of exploratory analysis of this study.

No significant financial relationships to disclose.

The adenocarcinoma-specific stage shift: Closely-repeated low-dose helical CT screening in a high-risk cohort for 10 years

1006

Background: Trials of CT screening for lung cancer have not yet proven the presence of a stage shift, to say nothing of a mortality benefit. On the basis of an update from Anti-Lung Cancer Association project, we investigated whether the stage shift did occur during the long-term closely-repeated low-dose helical CT screening in a high-risk cohort. Methods: A total of2,120 participants (mean age 63 yrs, 87% male, and 83% smoker) underwent low-dose helical CT screening semiannually from 1993 to 2004 (median, 3.5 years). Results: Nineteen prevalence and 57 incidence lung cancers were detected. In comparison between baseline and repeated screening, the detection rate was 0.90% vs. 0.32% (P < 0.001) and the tumor size was 24mm vs. 17mm (P = 0.018). Adenocarcinoma (74% and 63%) and stage IA (58% and 79%) were observed most commonly in both screen-groups, respectively, but their proportions showed no significant difference between groups, respectively. Regarding the survival of lung cancer patients, screening type was not a significant prognostic factor. In repeated screening,the detection rate oflung cancer except bronchioloalveolar carcinoma increased significantly depending on CT repeating times (r = 0.50, P = 0.020). Moreover, the proportion of stage II-IV and the tumor size decreased significantly only in invasive adenocarcinoma (r = -0.77, P = 0.007 and r = -0.60, P = 0.029, respectively). Conclusions: The adenocarcinoma-specific stage shift did occur in a high-risk cohort. Considering larger proportion of adenocarcinoma in this population, smokers might benefit from the long-term closely-repeated low-dose helical CT screening.

No significant financial relationships to disclose.

Spontaneous reactivation of Shiga toxins in Escherichia coli O157:H7 cells caused by transposon excision

IS1203v is an insertion sequence which has been found in inactivated Shiga toxin 2 genes (stx2) of Escherichia coli O157:H7. Using PCR amplification, we detected the wild-type stx2 genes in colonies of E. coli O157:H7 which possessed stx2 genes inactivated by insertion of IS1203v. This suggests that IS1203v is excised from the inactivated stx2 genes in E. coli O157:H7. We isolated the cells possessing the wild-type stx2 genes, and confirmed Stx2 productivities by reversed passive latex agglutination. We also analyzed the frequency of the appearance of the Stx2-producing cells using a quantitative PCR method. As a result, the frequency was 3.00 x 10(-6) with culturing for 24 h at 37 degrees C, and this increased to 8.83 x 10(-5) when E. coli O157:H7 possessing the inactivated stx2 genes was transformed by an expression plasmid harboring the IS1203v transposase. These results showed that some Stx2-nonproducing E. coli O157:H7 strains could be spontaneously changed into Stx2-producing cells.

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.

[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]

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.

Pure acute subdural haematoma without subarachnoid haemorrhage caused by rupture of internal carotid artery aneurysm

A 52-year-old female presented with disturbance of consciousness and clinical signs of tentorial herniation. Computed tomography showed a pure acute subdural haematoma (SDH) over the left convexity without subarachnoid haemorrhage. Cerebral angiography showed a saccular aneurysm at the junction of the left internal carotid artery and the posterior communicating artery. Surgery to remove the haematoma and clip the aneurysm showed the rupture point was located in the anterior petroclinoid fold (subdural space). The patient recovered without neurological deficits. Pure SDH caused by ruptured aneurysm is rare. Rupture of an aneurysm adhered to either the dura or falx and located in the subdural space may cause pure SDH. Therefore, ruptured intracranial aneurysm should be considered as a cause of non-traumatic SDH. Immediate removal of the SDH and aneurysmal clipping is recommended in such patients, even those in poor neurological condition.

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.

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.

Predicting the prognosis of non-small cell lung cancer patient treated with conservative therapy using contrast-enhanced MR imaging

The aim of this study was to evaluate the therapeutic effect more accurately and predict the prognosis of treated non-small cell lung cancer by using contrast-enhanced magnetic resonance imaging (CE-MRI). Contrast-enhanced computed tomography (CE-CT) and CE-MRI were examined 90 non-small cell lung cancer patients treated with conservative therapies. Enhancement patterns of CE-MRI were classified into three types: peripheral; mottled; and homogeneous. Reduction ratio of tumor size (RRT) based on the World Health Organization response criteria and a new response rate; reduction ratio of viable tumor size (RRVT) which evaluates not only the reduction of tumor size but also changes in necrosis and/or cavity size, were evaluated. Changes of enhancement pattern were compared and correlated with pathological diagnosis. The RRTs, RRVTs, and interobserver agreements evaluated by all modalities were compared. The RRTs and RRVTs in each subgroup were correlated and compared with prognoses. Change of enhancement pattern depended on therapy had no tendency (p = 0.06). Enhancement pattern had significant correlation with pathological diagnosis (p < 0.0001). Partial response (PR) case of RRVT had significant difference between imaging techniques (p = 0.04). The RRVT of other cases and RRT had no significant difference. Interobserver agreements of RRT and RRVT were almost perfect (n > or = 0.93). Prognosis had better correlation with RRVT than with RRT. Differences of relapse-free survival and survival between patients considered as having no change (NC) by RRT and PR by RRVT (NC-PR) and patients considered as having NC by RRT and RRVT were significant (p = 0.03, p = 0.01). There were no significant differences of relapse-free survival and survival between NC-PR patients and patients considered as having PR by RRT and RRVT. The CE-MRI technique could accurately evaluate the therapeutic effect and predict the prognosis of treated non-small cell lung cancer.

Effect of fluvoxamine on the pharmacokinetics of mexiletine in healthy Japanese men

BACKGROUND AND OBJECTIVES

Fluvoxamine, a selective serotonin reuptake inhibitor, is known to inhibit several hepatic cytochrome P450 (CYP) isozymes, in particular CYP1A2. Mexiletine is mainly catalyzed by CYP2D6 and partially catalyzed by CYP1A2. Our objective was to study the potential pharmacokinetic interaction between fluvoxamine and mexiletine.

METHODS

A randomized crossover design with two phases was used. A 7-day washout period separated the two treatment conditions. In the one phase, 6 healthy Japanese men received an oral dose of 200 mg of mexiletine alone (study 1); in the other phase, the men received fluvoxamine (50 mg twice a day) for 7 days, and on the eighth day they received oral mexiletine (200 mg) and fluvoxamine concomitantly (study 2). The concentrations of mexiletine were measured with HPLC.

RESULTS

The area under the concentration-time curve and serum peak concentration of mexiletine in study 2 were significantly increased compared with those in study 1 (10.4 +/- 4.85 versus 6.70 +/- 3.21 microg x h/mL, P =.006 and 0.623 +/- 0.133 versus 0.536 +/- 0.164 microg/mL, P =.008, respectively).

CONCLUSION

The effect of fluvoxamine on the mexiletine disposition is comparatively large, and when mexiletine and fluvoxamine are coadministered careful monitoring of mexiletine is needed.

Multiphase ECG-triggered 3D contrast-enhanced MR angiography: utility for evaluation of hilar and mediastinal invasion of bronchogenic carcinoma

The purpose of this study was to evaluate the usefulness of cardiac synchronized magnetic resonance angiography [electrocardiographically (ECG)-triggered MRA] for improving image quality and detection of hilar and mediastinal invasion of bronchogenic carcinoma. Fifty patients, suspected of having hilar or mediastinal invasion of bronchogenic carcinoma, underwent contrast-enhanced computed tomography and MR imaging including conventional and ECG-triggered MRA. Twenty patients subsequently also underwent surgical resection. Vascular enhancement-to-background ratio (VBR), vascular enhancement-to-tumor ratio (VTR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and image quality scores of thoracic vessels obtained with both MRA techniques were determined and compared. In addition, the diagnostic accuracy of tumor invasion of pulmonary vessels was compared. VBRs and VTRs of both MRA techniques were not significantly different. ECG-triggered MRA significantly improved SNRs and CNRs (P < 0.05). Two readers judged that overall image quality of ECG-triggered MRA was better than that of conventional MRA (kappa > or = 0.41). In conclusion, ECG-triggered MRA improves the image quality and the detection of hilar and mediastinal invasion of bronchogenic carcinoma.

Computed tomography screening for lung carcinoma in Japan

BACKGROUND

In Japan, lung carcinoma is the leading cause of cancer-related deaths. Adenocarcinoma accounts for roughly half of all lung carcinomas. Earlier detection of lung carcinoma is expected to reduce mortality rates. Computed tomography (CT) provides higher contrast resolution and greater visualization of chest compartments that are difficult to view with chest radiography, such as the mediastinum. CT further permits the detection of minute peripheral nodules. At present, several institutions and research groups are evaluating the utility of low dose spiral CT for lung carcinoma screening.

METHODS

From September 1993 to December 1998, 1669 individuals underwent a biannual screening program for lung carcinoma. The program included posteroanterior radiograph, sputum cytology, and low dose spiral CT at a for-profit organization: The Anti-Lung Cancer Association (ALCA). A total of 9993 examinations were carried out. The low dose spiral CT parameters used were 120 kvP, 50 mA, 10-mm collimation, and 2:1 pitch.

RESULTS

Peripheral lung carcinoma was detected in 31 of 9993 examinations (0.3%). Of the 31 cases, 24 tumors (77%) were detected by low dose spiral CT but were not visible on standard chest radiography. Twenty-two of the 24 tumors were Stage IA (T1N0M0, according to staging system revised in 1997).

CONCLUSIONS

Low dose spiral CT shows promise for lung carcinoma screening. The effectiveness of the technique for the detection of minute lung lesions remains to be established. Routine use of the technique will require resolution of several issues. These issues include the establishment of CT diagnostic criteria, the development of a diagnostic support system, the establishment of methods for definite diagnosis, and assessments of efficacy.

GM-CSF gene therapy using adenoviral vector in hamster pancreatic cancer

The aim of this study was to examine the antitumor effect of irradiated granulocyte macrophage-colony-stimulating factor (GM-CSF)-gene-transduced hamster pancreatic cancer cells and its relationship to the amount of GM-CSF produced by transduced tumor cells. Hamster pancreatic adenocarcinoma cells, HPD1NR, which spontaneously secrete 15.0+/-0.4 pg/106 cells per 24 h of GM-CSF, and HPD2NR cells, which do not secrete GM-CSF, were used. When these cells were infected with recombinant adenovirus harboring the GM-CSF gene, HPD1NR and HPD2NR secreted 624.2+/-9.9 and 157.8 +/-5.7 pg/106 cells per 24 h, respectively. Vaccination with irradiated GM-CSF-secreting HPD2NR completely protected syngeneic hamsters challenged with live parental cells. On the other hand, vaccination with irradiated HPD1NR protected 60% of hamsters from tumor development after challenge with parental cells. None of the tumor-free hamsters initially vaccinated with irradiated GM-CSF-producing HPD2NR cells developed tumor upon repeated challenge with parental cells during the entire observation period. Irradiated GM-CSF-gene-transduced hamster pancreatic cells are promising as a novel adjuvant cancer therapy after surgery for primary and metastatic pancreatic cancer. The results indicate the necessity for a therapeutic strategy for cancer based on the cytokine status of tumors.