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Purpose Increased use of deep convolutional neural networks (DCNNs) in medical imaging diagnosis requires determinate evaluation of diagnostic performance. We performed the fundamental investigation of diagnostic performance of DCNNs using the detection task of brain metastasis. Methods We retrospectively investigated AlexNet and GoogLeNet using 3117 positive and 37961 negative MRI images with and without metastasis regarding (1) diagnostic biases, (2) the optimal K number of K-fold cross validations (K-CVs), (3) the optimal positive versus negative image ratio, (4) the accuracy improvement curves, (5) the accuracy range prediction by the bootstrap method, and (6) metastatic lesion detection by regions with CNNs (R-CNNs). Results Respectively, AlexNet and GoogLeNet had (1) 50 ± 4.6% and 50 ± 4.9% of the maximal mean ± 95% confidence intervals (95% CIs) measured with equal-sized negative versus negative image datasets and positive versus positive image datasets, (2) no less than 10 and 4 of K number in K-CVs fell within the respective maximum biases of 4.6% or 4.9%, (3) 74% of the highest accuracy with equal positive versus negative image ratio dataset and 91% of that with four times of negative-to-positive image ratio dataset, (4) the accuracy improvement curves increasing from 69% to 74% and 73% to 88% as positive versus negative pairs of the training images increased from 500 to 2495, (5) at least nine and six out of 10-CV result sets essential to predict the accuracy ranges by the bootstrap method, and (6) 50% and 45% of metastatic lesion detection accuracies by R-CNNs. Conclusions Our research presented methodological fundamentals to evaluate diagnostic features in the visual recognition of DCNNs. Our series will help to conduct the accuracy investigation of computer diagnosis in medical imaging.

The current buckling design standard of Class 1 vessels for fast reactors (FRs) power plant in Japan, “Design and Construction for Nuclear Power Plants, Division 2 Fast Reactors” by the Japan Society of Mechanical Engineers, focuses primarily on plastic buckling of austenitic stainless steel vessel. For next-generation FRs, the higher-yield material, especially ASME Grade 91 steel, plans to be applied to the vessels such as steam generators in addition to austenitic stainless steel. Seismic isolation system is also being devised in the next plant to meet the design seismic load in Japan. To accommodate these conditions, the standard buckling strength equations in Japan were proposed in previous study, which were modified by considering elasto–plastic buckling of vessel. The modified equations consisted of elasto–plastic axial compression, bending, shear buckling, and their interactions, as well as ASME/BPVC CASE N-284, considering the reduction of buckling strength by cyclic larger vertical load with long–period lower horizontal load under the horizontal seismic isolation plant design. The applicability of the modified buckling equations to high-yield material was confirmed by a series of buckling tests under the monotonic load to Grade 91 steel vessels with an initial imperfection mode in previous study. In this study, the applicability of the proposed modified buckling equations was confirmed through a series of buckling tests under cyclic loading considering horizontal seismic isolation, or with the circumferential wrinkle shape corresponding to elephant’s foot buckling (EFB) mode as the conservative initial imperfection shape. These tests were simulated by elasto–plastic buckling analyses considering stress–strain relationship and imperfections in the test vessels with high accuracy, and these test and analysis results showed the applicability of the modified equations. The effect of initial imperfection shape of large vessels manufactured by multiple plates welding on the buckling load was evaluated via a series of analyses. In these analyses, the superimposition of global imperfection shape due to accumulation of misalignment of plates in the buckling mode imperfection, and the local imperfection and residual stress by welding had minimal effect on the buckling load. These buckling test and analysis results confirmed the contribution of the factors to the buckling strength such as initial imperfection and loading, and showed that the modified equations are applicable to the vessels in FRs power plant.

Purpose To clarify the accuracy of vertebral puncture of the vertebral tertile area needling (VETERAN) method puncturing the pedicle superimposed on one-third of the width between the lateral vertebral line to the contralateral medial lamina line compared with Cathelin-needle-assisted puncture (CAP) method puncturing using the Cathelin needle as a guide in percutaneous vertebroplasty. Materials and methods 449 punctures by CAP method and 125 punctures by VETERAN method were enrolled. We compared the puncture accuracy of both methods. We estimated a vertebral estimated tilting ratio (VET-ratio) defined as ratio of the distance between the lateral vertebral line and the contralateral medial laminal line to the distance between the vertebral lateral line and the puncture point measured by computed tomography. We also estimated the procedural items and clinical outcomes. Results VETERAN method with 100% of punctures within safe zone (cortical breaches within 2 mm) had significantly higher accuracy than CAP method with 97.8% (p p p Conclusion VETERAN method reduced the occurrence of the inaccurate puncture, operative times, and exposure times. A VET-ratio with 36% or less is associated with a safe puncture using VETERAN method.

Larger-diameter cylindrical vessels for commercial fast breeder reactors (FBRs) are planned to increase the electric generation capacity with thinner vessels compared to the existing ones. The modified 9Cr-1Mo steel (ASME Grade 91 steel) has high yield stress and low tangent modulus after yielding, and plans to be applied as well as austenitic stainless steel for vessels in existing FBR power plants. Although elasto-plastic axial compression, bending and shear buckling are expected to occur in vessels, the current buckling strength evaluation from the Japan Society of Mechanical Engineers (JSME) standard “Design and Construction for Nuclear Power Plants, Division 2 Fast Reactors” mainly focuses on plastic buckling of thick cylindrical vessels. Seismic base isolation is being devised for next-generation FBR power plants by the increasing seismic design load in Japan. When a horizontal seismic base isolation design is adopted, cylindrical vessels are subject to cyclic vertical seismic load with long-period horizontal seismic wave. The deformation by cyclic vertical load reduces the buckling strength. In this paper, we modified the existing buckling strength equations focusing on elasto-plastic axial compression, bending and shear buckling under cyclic axial load (hereinafter called “modified equations”), and confirmed their applicability through a series of elasto-plastic buckling analyses. We also conducted a series of buckling tests on Grade 91 steel vessels in the load regions where axial compression, bending and shear buckling interact, and where axial compression and bending buckling are dominant due to large vertical load. The buckling behavior and the buckling load estimated by the elasto-plastic buckling analysis considering the actual material stress–strain relationship and imperfections in the test vessel suitably agreed with corresponding test results in the load regions.

Mucormycosis is a life-threatening infectious disease that occurs most commonly in immunocompromised patients such as those with hematological malignancies. Its clinical symptoms and associated radiological findings vary and specific biomarkers and culture characteristics have not been defined. An 85-year-old man who had been treated for myelodysplastic syndrome and tuberculosis for several months presented with subacute fever and worsening left-side chest pain. Contrast-enhanced computed tomography images depicted massive tumor-like consolidation without enhancement, expanding from the left lower lobe. Emboli that did not respond to anticoagulants were detected in the left descending pulmonary artery. Despite intensive treatment he developed multiple organ failure and died 47 days after hospitalization. Gross pathology of a lung autopsy specimen revealed left lower pulmonary arterial emboli and pulmonary infarction, which was concluded to be the direct cause of death. The emboli were histopathologically identified as invasive mycelia in vessels. Mucor sp. was detected via real-time polymerase chain reaction and immunohistopathological analyses revealed that the mold in the blood vessels of lung tissue was partially positive for the mucor antigen. In the present case of Mucor sp. pulmonary emboli in a patient with myelodysplastic syndrome, radiographic findings were hard to distinguish from those typical of a lung abscess.

We performed CT-guided percutaneous uterine biopsy in three females for whom diagnosis by endometrial brushing cytology and endometrial biopsy had proved difficult. In each case, a percutaneous tumor biopsy was performed using CT fluoroscopy with reference to the MR images obtained beforehand. The sampling of multiple biopsy specimens was successful by the coaxial method using a 16/18G Quick-Core biopsy needle in all the cases, and definitive histopathologic diagnoses were achieved. The final pathological diagnoses were one benign lesion (pseudowidening of adenomyosis) and two malignant lesions (small cell carcinoma and adenocarcinoma of Mullerian origin of ovaries). There were no associated complications. The treatment strategy was formulated according to the results of the pathological diagnosis in each case, and consisted of either hormonal therapy or systemic chemotherapy.

The confusion of MRI sequence names could be solved if MR images were automatically identified after image data acquisition. We revealed the ability of deep learning to classify head MRI sequences. Seventy-eight patients with mild cognitive impairment (MCI) having apparently normal head MR images and 78 intracranial hemorrhage (ICH) patients with morphologically deformed head MR images were enrolled. Six imaging protocols were selected to be performed: T2-weighted imaging, fluid attenuated inversion recovery imaging, T2-star-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient mapping, and source images of time-of-flight magnetic resonance angiography. The proximal first image slices and middle image slices having ambiguous and distinctive contrast patterns, respectively, were classified by two deep learning imaging classifiers, AlexNet and GoogLeNet. AlexNet had accuracies of 73.3%, 73.6%, 73.1%, and 60.7% in the middle slices of MCI group, middle slices of ICH group, first slices of MCI group, and first slices of ICH group, while GoogLeNet had accuracies of 100%, 98.1%, 93.1%, and 94.8%, respectively. AlexNet significantly had lower classification ability than GoogLeNet for all datasets. GoogLeNet could judge the types of head MRI sequences with a small amount of training data, irrespective of morphological or contrast conditions.

To retrospectively analyze the safety and efficacy of percutaneous vertebroplasty (PVP) for patients aged 90 or over. We analyzed 130 consecutive patients with osteoporotic vertebral fractures who underwent a first-time PVP between May 2015 and September 2017 at our institution. We divided them into the elder patient group aged 90 years or over (n = 21) and the younger patient group under 90 years (n = 109). We compared the two groups’ background, treatments, and outcomes using univariate analyzes and the log rank test. A significant difference was observed in dementia (19% in the younger group vs. 48% in the elder group, p

Corresponding Author: Dr. Tsuyoshi Tajima Email: ttajima@hosp.ncgm.go.jp Received: October 17, 2015|Accepted: December 14, 2015 | Published Online: January 15, 2016 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (creativecommons.org/licenses/by/3.0) Conflict of interest: None declared | Source of funding: Nil | DOI: http://dx.doi.org/10.17659/01.2016.0006

Diffuse pulmonary lymphangiomatosis (DPL) is a rare lymphatic disease that can cause diverse respiratory symptoms. A 22-year-old man, whose chest CT had shown an abnormality for years, presented with acute respiratory failure due to the abrupt onset of hemoptysis. The diagnosis of DPL was confirmed by surgical lung biopsy and lymphangiography. Histopathological investigation showed dilated vascular and lymphatic vessels. DPL can cause acute and life-threatening symptoms during its chronic clinical course. A coexisting anomaly in the venous system may be present in DPL patients with hemoptysis.

In-111 ibritumomab tiuxetan pretherapy imaging is performed prior to radioimmunotherapy with Y-90 ibritumomab tiuxetan in patients with lymphoma in order to estimate the biodistribution of the radiolabeled antibodies. We report the case of a 61-year-old woman with relapsed follicular lymphoma. In-111 ibritumomab tiuxetan pretherapy imaging showed tracer accumulation in a surgically treated fracture of the left calcaneus as well as in the involved lesions. The patient had fractured her left calcaneus 6 months before the radioimmunotherapy, and fracture of the left calcaneus without lymphoma involvement had been revealed operatively at that time. Clinical features and magnetic resonance imaging (MRI) indicated an inflammatory response in the left heel. We concluded that this inflammation played an important role in the uptake on pretherapy imaging. It should be kept in mind that the inflammation is a differential diagnosis of lymphoma involvement in In-111 ibritumomab tiuxetan pretherapy imaging. To the best of our knowledge, this is the first case report of In-111 ibritumomab tiuxetan uptake in a surgically treated fracture.

Background: Recent studies have reported the clinical usefulness of the soft-copy reading of mammograms. However, image-processing parameters for soft-copy reading of digital mammograms have not been established. Purpose: To compare observer performance in detecting breast cancer by soft-copy reading of digital mammograms using a routine image-processing parameter versus each of several high-contrast parameters. Material and Methods: The mammograms of 154 breasts, including 48 abnormal breasts with breast cancer and 106 normal breasts, were examined. Cancers were classified into 34 mass-dominant cancers, 11 microcalcification-dominant cancers, two cancers showing only architectural distortion, and one cancer without abnormal findings. All mammograms were performed using a computed radiography (CR) system. Each image was processed using GA (1.2), which was the contrast parameter recommended by the manufacturer for hard-copy film, GA (1.4), GA (1.6), and GA (1.8). These images were displayed on 5-megapixel (M) liquid-crystal display monitors. Five experienced radiologists classified them into BI-RADS category 1–2 or 3–5, and were also asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of masses and microcalcifications in each breast. Results: In mass-dominant cancers of dense breast tissue, the mean sensitivities of GA (1.2), GA (1.4), GA (1.6), and GA (1.8) were 32.7, 38.2, 36.4, and 40.0, and the AZ values were 0.67, 0.73, 0.71, and 0.73, respectively; in microcalcification-dominant cancers, the mean sensitivities were 80.0, 74.5, 80.0, and 78.2, respectively; however, there were no significant differences among them. Conclusion: High-contrast parameters tended to show relatively high sensitivity and AZ values in the detection of masses in dense breast tissue, but relatively low sensitivity for microcalcifications.

We report two cases of inflammatory myofibroblastic tumor (IMT) of the lung in a 4-year-old boy and a 7-year-old girl. We performed dynamic contrastenhancement computed tomography in both of our cases and dynamic contrast enhancement magnetic resonance imaging (MRI) in one case. These dynamic studies showed a demarcated mass with delayed enhancement in both cases. A T1-weighted MR image shows a mass with homogeneous low signal intensity, and a T2- weighted image shows a mass with slightly high signal intensity. A post-contrast-enhanced T1-weighted image demonstrates homogeneous enhancement. We speculate that the delayed enhancement could be attributed to the abundant fibrous tissue, which was the main structural material of the tumor. This same finding has been described in previous reports of IMT in other organs.

To determine the value of adding diffusion-weighted (DW) magnetic resonance (MR) imaging to dynamic contrast material-enhanced MR imaging when distinguishing between benign and malignant parotid tumors.This retrospective study was approved by the institutional review board, and the informed consent requirement was waived. The authors analyzed MR images of 50 lesions (36 benign, 14 malignant) in 47 patients. DW MR imaging and dynamic contrast-enhanced MR imaging were performed in all patients. Time-intensity curve (TIC) patterns were categorized as follows: type A, time to peak was more than 120 seconds; type B, time to peak was 120 seconds or less with high washout ratio (or = 30%); type C, time to peak was 120 seconds or less with low washout ratio (30%); and type D, flat. The apparent diffusion coefficient (ADC) values were measured on DW MR images. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for type A, B, and D tumors regarded as benign and for type C tumors regarded as malignant. On the basis of DW MR imaging results, ADC threshold values between pleomorphic adenomas and carcinomas and between Warthin tumors and carcinomas were selected. Diagnostic accuracy was compared before and after modification diagnosis referring to the ADC value obtained with the McNemar test. P.05 was considered to indicate a significant difference.ADC threshold values were 1.4 x 10(-3) mm(2)/sec between pleomorphic adenomas and carcinomas and 1.0 x 10(-3) mm(2)/sec between Warthin tumors and carcinomas. Accuracy (82% vs 94%) and positive predictive value (67% vs 92%) significantly improved with the addition of ADC values in the evaluation of patients with type B or C tumors.A persistent or flat TIC pattern on dynamic contrast-enhanced MR images indicates benign disease, but there is added value from including the ADC value in the evaluation of tumors that show a plateau or washout TIC pattern.

Purpose: We investigated whether change in muscle microstructure associated with passive extension and contraction affects proton diffusivity. Material and Methods: In 6 male subjects, we compared apparent diffusion coefficients (ADC) along the posterior-to-anterior (ADC-PA), right-to-left (ADC-RL) and superior-to-inferior (ADC-SI) directions of the right tibialis anterior muscle with the ankle joint in passive plantar flexion and passive dorsiflexion. Results: Compared to the respective ADCs at plantar flexion, the ADC-PA (P=0.002) and ADC-RL (P=0.008) were significantly greater, but ADC-SI (P=0.008) significantly lower at dorsiflexion. Conclusion: Our results indicate that change in muscle microstructure associated with passive extension and contraction would affect proton diffusivity, and this alteration of proton diffusivity could be detected by measuring ADC with a clinical magnetic resonance scanner.

Purpose: We evaluated the magnetic resonance (MR) features of breast lesions showing circumscribed mass on mammography to understand the characteristics that differentiate malignancy and benignancy. Materials and Methods: Our institutional review board approved the study, and informed consent was waived. Using logistic regression analysis, we examined morphologic and kinetic MR imaging data of 90 breast lesions (43 malignant, 47 benign) that showed circumscribed mass on mammography. Results: Features identified as having high odds for malignancy included: rim enhancement (odds ratio, 70.894; 95% confidence interval (CI), 7.525-667.938); heterogeneous enhancement (odds ratio, 10.839; 95% CI, 1.032-113.856); and washout dynamic pattern (odds ratio, 46.262; 95% CI, 3.716-575.901). Combinations of washout dynamic pattern and either rim or heterogeneous enhancement reflected excessively high prediction probability for malignancy (>0.95), whereas combinations lacking washout dynamic pattern and with either homogeneous enhancement or dark internal septation revealed excessively low prediction probability for malignancy (

Objective To characterize MR imaging features of pure mucinous carcinoma of the breast. Materials and methods MR images obtained from 16 women (age range, 29–81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings. Results Eleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass. Conclusions MR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.

The aim of the study is to evaluate the reliable production of temporal subtraction images in a picture archiving and communication system environment and to establish objective criteria for the evaluation of image quality. A total of 117 temporal subtraction chest images (55 in the upright position, 62 in the supine position) were obtained in five consecutive days. In all of these, we confirmed that there were no interval changes on the original images, and cases with diffuse lung disease were excluded. The temporal subtraction images were classified by three chest radiologists into five levels: 5, excellent; 4, good; 3, acceptable; 2, poor; and 1, very poor. The following were examined: (1) the yield of adequate quality of the temporal subtraction images; (2) whether the temporal subtraction images were obtained in the warping or nonwarping mode; and (3) the correlation of the overall subjective image quality with the relative shift angles, relative shift distances, and the standard deviation of gray levels in the temporal subtraction images. The percentages of acceptable temporal subtraction images were 100% and 66% in the upright and supine positions, respectively. Sixteen (26%) of the 62 supine-position images were made in nonwarping mode, whereas all upright images were made in warping mode. Significant correlations were obtained in the relative shift angle (P < 0.05), relative horizontal shift distance (P < 0.05), and standard deviation of gray levels (P < 0.0001). Temporal subtraction images with acceptable image quality were obtained in the upright position. The objective criteria may be useful for the evaluation of image quality.

The case of a 46-year-old woman with lymphangioleiomyomatosis (LAM) involving the supraclavicular, mediastinal, and pelvic lymph nodes in addition to the lungs is reported. Computed tomography incidentally revealed multiple thin-walled pulmonary cysts and low-attenuating masses in the supraclavicular, mediastinal, and retroperitoneal lymph nodes. A biopsy of the supraclavicular mass was performed and diagnosed as LAM histopathologically. The common sites of extrapulmonary LAM include retroperitoneal and mediastinal lymph nodes; however, supraclavicular lymph node involvement is extremely rare.

We report a case of Gorham's disease of the chest wall in a 29-year-old man. A chest radiograph showed osteolysis of the left first, second, and third ribs. CT and MR images revealed a soft tissue mass around the affected ribs. The mass presented as having heterogeneous high signal intensity on T2-weighted MR images, and it showed minimal enhancement on contrast-enhanced MR images. A histologic specimen obtained by incisional biopsy from the left third rib revealed proliferation of lymphangiomatous tissue in the bone marrow. A diagnosis of Gorham's disease was made based on these clinical, radiologic, and histologic findings.

We present a case of pulmonary metastasis from pancreatic cancer with biphasic radiological patterns: demarcated nodules, irregularly shaped opacities showing the so-called ‘air-space pattern’, and both typical and atypical radiological findings. The histology of the demarcated nodules was poorly differentiated adenocarcinoma identical to the pancreatic tumor, while that of the irregularly shaped opacities was well-differentiated adenocarcinoma showing a lepidic growth pattern. Pulmonary metastasis from pancreatic cancer may contain components of various differentiations showing different radiological findings.

Pulmonary synovial sarcoma is a rare disease, and reports detailing clinicians' radiological findings are few. We report a case of a primary pulmonary synovial sarcoma in a 68-year-old woman. Chest CT revealed a well-defined and homogeneous oval mass measuring 3×2.5 cm in the left lower lobe in contact with the visceral pleura. No pleural effusion was evident. No calcification or fat component was detected. The tumor showed homogeneous hypointensity on both T1- and T2-weighted MR imaging. In this case, a lung metastasis could be excluded with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), and the final diagnosis was histopathologically confirmed by the chimeric gene detection.

We compared observer performance of digital mammography among hard-copy readings and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. Five experienced radiologists assessed 80 mammograms of 40 cancers and 40 benign lesions. There were no significant differences among the average A(z) of three modalities and among the κ values for intra- and interobserver agreement. The soft-copy reading using the 3M LCD monitor took a slightly longer time, although there were no significant differences.

Purpose To evaluate the diagnostic accuracy of a combination of dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion-weighted MR imaging (DWI) in characterization of lesions showing non-mass-like enhancement on breast MR imaging and to find the strongest discriminators between carcinoma and benignancy. Materials and methods We analyzed consecutive MR images in 45 lesions showing non-mass like enhancement in 41 patients. We analyzed lesion size, distribution, internal enhancement, kinetic curve pattern, and apparent diffusion coefficient (ADC) values. We applied univariate and multivariate analyses to find the strongest indicators for malignancy. In a validation study, 22 non-mass-like enhancement lesions in 21 patients were examined. We calculated diagnostic accuracy when we presume category 4b, 4c, and 5 lesions as malignant or high to moderate suspicion for malignancy, and category 4a and 3 as low suspicion for malignancy or benign. Results Segmental distribution (P = 0.018), clumped internal enhancement (P = 0.005), and ADC less than 1.3 × 10−3 mm2/s (P = 0.047) were the strongest MR indicators of malignancy. In a validation study, sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 87% (13/15), 86% (6/7), 93% (13/14), 75% (6/8) and 86% (19/22), respectively. Conclusion The combination of DCE-MRI and DWI showed high diagnostic accuracy in characterization of non-mass-like enhancement lesions on breast MR images.

Purpose To examine the manner in which cardiac function affects the magnitude and timing of aortic contrast enhancement during coronary CT angiography (CTA). Materials and methods Twenty-nine patients (21 men, 8 women; mean age, 64.4 ± 13.4 years; mean weight, 59.4 ± 10.3 kg) underwent measurement of cardiac output within 2 weeks of coronary CTA. The cardiac output of each patient was measured by the thermodilution technique and the cardiac index was calculated from the body surface area. During coronary CTA, attenuation of the descending aorta was measured at the workstation every 3 s. The aortic peak time (APT) and aortic peak enhancement (APE) of each patient were calculated. Pearson's correlation coefficient analysis was used to investigate the relationships between the cardiac output or cardiac index and APT or APE. Furthermore, the relationship between patient factors or parameters on test bolus injection and APT or APE was also evaluated. Results The range of cardiac output, cardiac index, APT, and APE was 1.55–10.46 L/min (mean: 4.77 ± 2.13), 1.11–5.30 L/(min-m 2 ) (mean: 3.28 ± 1.08), 25–51 s (mean: 38.3 ± 7.5), and 273.1–598.1 HU (mean: 390.4 ± 72.1), respectively. With an increase in the cardiac index, both APT ( r = −0.698, p r = −0.573, p = 0.0009) decreased. There were significant correlations between the patient body weight and APT and APE with the test bolus injection, and with APT and APE during coronary CTA. Conclusion The APT and APE during coronary CTA are closely related to cardiac function.

Since 2002, Japan Nuclear Energy Safety Organization (JNES) has been carrying out seismic capacity tests for several types of equipment which significantly contribute to core damage frequency. The primary purpose of this study is to acquire the seismic capacity data of thin walled cylindrical liquid storage tanks in nuclear power plants and to establish an evaluation procedure of the ultimate strength. As for the refueling water storage tank and the condensate storage tank which are used in PWR plants, elephant-foot bulge (EFB) is the typical buckling behavior of those tanks and the primary failure mode to be focused on. In the previous study, by conducting the dynamic and static buckling tests with aluminum alloy, it was confirmed that static buckling test represents dynamic buckling and post-buckling behavior in terms of energy absorption capacity. In this study, static buckling tests with actual material were performed in order to evaluate the ultimate strength of real tanks. Although the buckling mode did not differ among materials, tests with actual materials (steel, stainless steel) resulted higher seismic capacity compared to the aluminum alloy, and inner water leakage occurred from the cracks initiated at the secondary buckling on the EFB section.Copyright © 2008 by ASME

Purpose To investigate optimal gradation processing parameter for soft-copy reading comparing the parameter recommended for hard-copy with other parameters. Materials and methods Digital mammograms using a Computed Radiography system were evaluated. The gradation processing parameter recommended by the manufacturer was GA (1.2). We prepared seven parameters that changed the degree of contrast: GA (0.6, 0.8, 1.0, 1.2, 1.4, 1.6, and 1.8). Images of an anthropomorphic breast phantom were displayed on a 5-megapixel liquid crystal display monitor using each parameter. Three readers independently assessed each image, and scored for the following items: intramammary contrast, extramammary contrast, sharpness, and graininess. Total score was calculated in each parameter. We also displayed normal mammograms of nine cases: three with a scattered fibroglandular density, three with a heterogeneously dense breast, and three with an extremely dense breast. These were displayed using GA (1.2) or using parameters with a higher total score than GA (1.2) in the phantom test. Three readers assessed each mammogram as in the phantom test. Results In phantom test, GA (1.4), GA (1.6), and GA (1.8) obtained higher scores than GA (1.2). In normal cases tested using these parameters, GA (1.4) obtained the highest score. This was significantly higher than that of GA (1.2) ( P = 0.004). The score obtained for GA (1.4) was the highest in cases with extremely dense and heterogeneously dense breast tissue, though there was no statistically significant difference. Conclusion Soft-copy image quality was improved by gradient processing using higher contrast parameter than that routinely used in hard-copy, especially in dense breast cases.

Since May 2002, temporal subtraction and nodule detection systems for digital chest radiographs have been integrated into our hospital’s picture archiving and communication systems (PACS). Image data of digital chest radiographs were stored in PACS with the digital image and communication in medicine (DICOM) protocol. Temporal subtraction and nodule detection images were produced automatically in an exclusive server and delivered with current and previous images to the work stations. The problems that we faced and the solutions that we arrived at were analyzed. We encountered four major problems. The first problem, as a result of the storage of the original images’ data with the upside-down, reverse, or lying-down positioning on portable chest radiographs, was solved by postponing the original data storage for 30 min. The second problem, the variable matrix sizes of chest radiographs obtained with flat-panel detectors (FPDs), was solved by improving the computer algorithm to produce consistent temporal subtraction images. The third problem, the production of temporal subtraction images of low quality, could not be solved fundamentally when the original images were obtained with different modalities. The fourth problem, an excessive false-positive rate on the nodule detection system, was solved by adjusting this system to chest radiographs obtained in our hospital. Integration of the temporal subtraction and nodule detection system into our hospital’s PACS was customized successfully; this experience may be helpful to other hospitals.

To evaluate the usefulness of a commercially available computer-assisted diagnosis (CAD) system on operable T1 cases of lung cancer by use of digital chest radiography equipment. Fifty consecutive patients underwent surgery for primary lung cancer, and 50 normal cases were selected. All cancer cases were histopathologically confirmed T1 cases. All normal individuals were selected on the basis of chest computed tomography (CT) confirmation and were matched with cancer cases in terms of age and gender distributions. All chest radiographs were obtained with one computed radiography or two flat-panel detector systems. Eight radiologists (four chest radiologists and four residents) participated in observer tests and interpreted soft copy images by using an exclusive display system without and with CAD output. When radiologists diagnosed cases as positives, the locations of lesions were recorded on hard copies. The observers’ performance was evaluated by receiver operating characteristic analysis. The overall detectability of lung cancer cases with CAD system was 74% (37/50), and the false-positive rate was 2.28 (114/50) false positives per case for normal cases. The mean A z value increased significantly from 0.896 without CAD output to 0.923 with CAD output (P = 0.018). The main cause of the improvement in performance is attributable to changes from false negatives without CAD to true positives with CAD (19/31, 61%). Moreover, improvement in the location of the tumor was observed in 1.5 cases, on average, for radiology residents. This CAD system for digital chest radiographs is useful in assisting radiologists in the detection of early resectable lung cancer.

OBJECTIVE. The objective of our study was to evaluate chest radiographic and CT findings of patients with pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis. CT investigation was focused on the location, size, contour, and internal features of the lesions; migration of lesions; mediastinal lymphadenopathy; and pleural effusion.CONCLUSION. Pulmonary visceral larva migrans appears on CT as multifocal subpleural nodules with halo or ground-glass opacities and ill-defined margins.

The purpose of the study was to compare observer performance in the detection of masses and microcalcifications of breast cancer among hard-copy reading and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. For the microcalcification detection test, we prepared 100 mammograms: 40 surgically verified cancer cases and 60 normal cases. For the mass detection test, we prepared 100 mammograms: 50 cancer cases and 50 normal cases. After six readers assessed both microcalcifications and masses set for each modality, receiver operating characteristic (ROC) analysis was performed. The average A(z)s for mass detection using a hard copy and 3M and 5M LCD monitors were 0.923, 0.927 and 0.920, respectively; there were no significant differences. The average A(z) for microcalcification detection using hard copy, 3M and 5M LCD monitors was 0.977, 0.954 and 0.972, respectively. There were no significant differences, but the P-values between the hard copy and 3M LCD monitor and that between the 3M and 5M LCD monitor were 0.08 and 0.09, respectively. In conclusion, the observer performances for detecting masses of breast cancers were comparable among the hard copy and two LCD monitors; however, soft-copy reading with a 3M LCD monitor showed slightly lower observer performance for detecting microcalcifications of breast cancers than hard-copy or 5M LCD monitor reading.

To determine whether muscle fiber atrophy associated with steroid myopathy can be detected with T2 relaxation time.Animal and human studies were approved by the ethics committee. Informed consent was obtained. Twelve rabbits were divided into a group that received 3 mg/kg of triamcinolone subcutaneously each day for 10 consecutive days (n = 6) and a control group that received saline (n = 6). Magnetic resonance (MR) imaging was performed before and after treatment. T2 and fat deposition ratio (FDR) of soleus and gastrocnemius muscles before and after treatment and between control rabbits and rabbits treated with steroids were compared by using two-way repeated analysis of variance and Bonferroni post hoc test to evaluate effects of steroid treatment. After imaging, rabbits were sacrificed. Extracellular space ratio (ECSR) and fiber diameter were examined. Correlation among T2, ECSR, and diameter of type 2 muscle fibers was analyzed with a Pearson correlation test with Bonferroni correction in gastrocnemius to determine factors affecting T2. In humans, T2 relaxation time and FDR of both muscles were compared between volunteers not treated with steroids and patients treated with steroids by using an unpaired t test to evaluate the effects of steroids.In rabbits, T2 of gastrocnemius muscle was significantly (P.01) longer after steroid treatment than before steroid treatment and was also significantly (P.01) longer than after saline administration. T2 of the gastrocnemius showed no significant difference in control rabbits before or after saline administration or in control rabbits and rabbits before steroid administration. T2 of the soleus muscle or FDR of either muscle showed no significant difference. There was a significant correlation (P.01) among T2, ECSR, and diameter of type 2 muscle fibers in the gastrocnemius. In humans, T2 of the gastrocnemius was significantly (P.01) longer in patients than in volunteers. T2 of the soleus or FDR of either muscle showed no significant difference.Muscle fiber atrophy associated with steroid myopathy is detectable as prolongation of T2 relaxation time in the gastrocnemius muscle; the authors believe prolongation of T2 relaxation time is mainly due to increased ECSR reflecting type 2 muscle fiber atrophy.

Nodular lymphoid hyperplasia (NLH) is one of the pulmonary lymphoproliferative disorders, and was initially described as pseudolymphoma. However, reports focusing on CT findings of NLH of the lung have been rare. We report a case of a pulmonary NLH in a 49-year-old woman who showed multiple pulmonary nodules on HRCT and was misdiagnosed preoperatively with adenocarcinoma on the basis of transthoracic cytology. A final diagnosis of NLH was made on postoperative histologic examination.

CT and MR findings of a case of brain aspergillosis with histopathologic correlation are reported. On both CT and MR images, there were multiple lesions in the corticomedullary junction (CMJ) that appeared to disrupt the cortical sulci and that were not enhanced by intravenous contrast material. In most of these lesions, there were centrally located structures that were enhanced by intravenous contrast material and that appeared to be continuous from markedly enhanced adjacent dilated cortical vessels. Histopathologic examination of the autopsy specimen showed multiple hemorrhagic infarcts in the CMJ with remaining dilated cortical vessels that had been thrombosed by aspergillus hyphae.

The purpose of this study was to determine the frequency, patterns of disease, and risk factors for development of pulmonary complications after liver chemoembolization via the inferior phrenic artery (IPA).Forty-four selective transcatheter hepatic chemoembolization (THCE) procedures via the IPA were performed in patients with primary liver cancers with use of a mixture of anticancer agents and iodized oil (Lipiodol) with or without transcatheter arterial embolization. The grades of pulmonary complications were assessed on triphasic helical computed tomographic (CT) images after THCE and were correlated with angiographic findings of the IPA, infused dosages of Adriamycin and Lipiodol, and hepatic venous tumor thrombus on triphasic CT images before THCE.THCE via the IPA frequently resulted in lung CT changes: Lipiodol accumulation in the lung field (52%), consolidation (68%), and pleural effusion (41%). Among 44 patients, two (5%) developed respiratory symptoms. An excellent correlation was shown between Lipiodol accumulation and the presence of angiographic abnormalities of the IPA (P.005). A significant correlation was also shown between the grades of pulmonary complications and the numbers of angiographic abnormalities (P.01). The grades of pulmonary complications increased according to the infused dosage of Adriamycin and Lipiodol (P.05).Angiographic abnormalities such as arteriovenous shunts, dilated anastomotic branches, and dense pleural staining are important risk factors for pulmonary complications of THCE via the IPA. Embolization for shunts may be required to prevent such complications, especially in cases with shunts to pulmonary vessels or hepatic veins.