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Background To evaluate the prognostic value of the apparent diffusion coefficient (ADC) derived from diffusion-weighted magnetic resonance imaging (MRI) and monitor the early treatment response to induction chemotherapy (IC) with plasma EBV DNA in locoregionally advanced nasopharyngeal carcinoma (LA-NPC). Results A total of 307 stage III-IVb NPC patients were prospectively enrolled. All patients underwent MRI examinations to calculate ADC and plasma EBV DNA measurements pretreatment and post-IC. The participants’ ADC value of 92.5% (284/307) increased post-IC. A higher percent change in ADC value (ΔADC%high group) post-IC was associated with a higher 5-year OS rate (90.7% vs 74.9%, p low group. Interestingly, ΔADC% was closely related to the response measured by RECIST 1.1 (p p = 0.037). The AUC significantly increased when post-IC plasma EBV DNA was added to ΔADC% to predict treatment failure. Thus, based on ΔADC% and plasma EBV DNA, we further divided the participants into three new prognostic response phenotypes (early response, intermediate response, and no response) that correlated with disparate risks of death (p = 0.001), disease progression (p p p Conclusion The percentage change in ADC post-IC is indicative of treatment response and clinical outcome. ΔADC% and plasma EBV DNA-based response phenotypes may provide potential utility for early termination of treatment and allow guiding risk-adapted therapeutic strategies for LA-NPC.

Background Nasopharyngeal carcinoma (NPC) may be cured with radiation therapy. Tumor proximity to critical structures demands accuracy in tumor delineation to avoid toxicities from radiation therapy; however, tumor target contouring for head and neck radiation therapy is labor intensive and highly variable among radiation oncologists. Purpose To construct and validate an artificial intelligence (AI) contouring tool to automate primary gross tumor volume (GTV) contouring in patients with NPC. Materials and Methods In this retrospective study, MRI data sets covering the nasopharynx from 1021 patients (median age, 47 years; 751 male, 270 female) with NPC between September 2016 and September 2017 were collected and divided into training, validation, and testing cohorts of 715, 103, and 203 patients, respectively. GTV contours were delineated for 1021 patients and were defined by consensus of two experts. A three-dimensional convolutional neural network was applied to 818 training and validation MRI data sets to construct the AI tool, which was tested in 203 independent MRI data sets. Next, the AI tool was compared against eight qualified radiation oncologists in a multicenter evaluation by using a random sample of 20 test MRI examinations. The Wilcoxon matched-pairs signed rank test was used to compare the difference of Dice similarity coefficient (DSC) of pre- versus post-AI assistance. Results The AI-generated contours demonstrated a high level of accuracy when compared with ground truth contours at testing in 203 patients (DSC, 0.79; 2.0-mm difference in average surface distance). In multicenter evaluation, AI assistance improved contouring accuracy (five of eight oncologists had a higher median DSC after AI assistance; average median DSC, 0.74 vs 0.78; P < .001), reduced intra- and interobserver variation (by 36.4% and 54.5%, respectively), and reduced contouring time (by 39.4%). Conclusion The AI contouring tool improved primary gross tumor contouring accuracy of nasopharyngeal carcinoma, which could have a positive impact on tumor control and patient survival. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Chang in this issue.

AIM To assess the feasibility and preliminary diagnostic performances of relaxation times derived from synthetic magnetic resonance imaging (syMRI) for differentiating nasopharyngeal carcinoma from nasopharyngeal benign lymphoid hyperplasia, and to assess the influence of tissue segmentation method on relaxation estimates. MATERIALS AND METHODS Fifty participants with nasopharyngeal carcinoma (NPC) and 40 participants with benign hyperplasia (NPH) who underwent syMRI examination were enrolled prospectively. T1, T2, and proton density (PD) values were obtained from four different regions of interest (ROIs), namely, partial‐section, single‐section, three‐sections, and whole‐lesion. The metrics between NPC and NPH or among different ROIs were compared using Student's t-test or one-way ANOVA. The area under curve (AUC) was calculated to assess the performance of metrics obtained from different ROIs to differentiate NPC and NPH. RESULTS The T1, T2, and PD values for NPH were significantly higher than those for NPC, regardless of the type of ROI used, except for the PD value obtained from the whole-lesion ROI. The T2 values obtained from the single-section ROI showed the highest diagnostic accuracy in distinguishing NPC from NPH, with an AUC of 0.894, sensitivity of 0.900, and specificity of 0.800. Additionally, the T1, T2, and PD values for nasopharyngeal lesions showed no statistical difference among different kinds of ROI, except for the difference in T1 value between partial‐section and other methods. CONCLUSION Quantitative analysis of syMRI has the potential to distinguish NPC from NPH. Moreover, different types of ROI showed limited influence on the relaxation time estimation for nasopharyngeal lesions.

To analyze the clinical outcomes of nasopharyngeal carcinoma (NPC) patients with post-radiation nasopharyngeal necrosis (PRNN) and construct a new risk classification system for predicting survival of PRNN.A total of 276 patients with PRNN were consecutively enrolled. Complete magnetic resonance (MR) images of the nasopharynx and neck were available for all patients and were used to assess nasopharyngeal necrosis status. After 2010, patients with PRNN were initially treated by radical endoscopic necrectomy followed by reconstruction with nasal flap (ENNF).The 1-year and 2-year overall survival (OS) was 65.0% and 51.6%, respectively. Three variables affected survival: osteoradionecrosis, re-irradiation, and internal carotid artery (ICA) exposure, and only two variables were found to be independent prognostic factors: re-irradiation (hazard ratio [HR] 1.75, P=0.001) and internal carotid artery (ICA) exposure (hazard ratio [HR] 1.80, P=0.001). These two variables were combined to create a new risk classification system for PRNN. 131 (47.5%), 110 (39.9%), and 35 (12.7%) patients were classified into low-, intermediate- and high-risk group, with the 2-year OS rates of 64.8%, 45.1%, and 22.5%, respectively (P0.001). ENNF was associated with a better OS in these three group patients compared with conservative management with statistical or marginal statistical significance (2-year OS low-risk group, 90.9% vs 61.1%, p=0.081; intermediate-risk group: 100% vs 37.8%, P=0.001; and high-risk group, 57.1% vs 20.8%, p=0.066).The new risk classification system provides accurate estimates of prognosis. ENNF surgery may lead to better survival outcome than conservative management in PRNN patients.

Purpose To evaluate the prognostic value of the restaging system after neoadjuvant chemotherapy (NACT) in patients with advanced-stage nasopharyngeal carcinoma (NPC). Materials and Methods This study was approved by the clinical research committee and a written informed consent was required before enrolling in the study. Prospectively enrolled were 412 consecutive patients with stage III-IVb NPC treated with NACT followed by concurrent chemotherapy and radiation therapy. Patients were staged before NACT and restaged after NACT. The progression-free survival (PFS) and distant metastasis-free survival (DMFS) were calculated with the Kaplan-Meier method, and differences were compared by using the log-rank test. Results Post-NACT T classification (PFS, P = .001) and N classification (PFS, P < .001; DMFS, P = .001) resulted in better survival curve separations than pre-NACT T classification and N classification. Patients downstaged from N2-N3 to N0-N1 disease had a better prognosis than did patients who continued to have N2-N3 diseases (3-year PFS, 83.8% vs 66.6%, P = .001; 3-year DMFS, 88.0% vs 78.4%, P = .026). Multivariate analysis revealed that post-NACT T classification (hazard ratio [HR] = 1.67; 95% confidence interval [CI]: 1.18, 2.36; P = .003) and post-NACT N classification (HR = 1.54; 95% CI: 1.17, 2.03; P = .002) were independent prognostic factors for PFS; also, post-NACT N classification (HR = 1.48; 95% CI: 1.05, 2.07; P = .025) was an independent prognostic factor for DMFS. Multivariate analysis in patients with N2-N3 disease demonstrated that the N downstaging effects of NACT was the only independent prognostic factor for PFS (HR = 0.48; 95% CI: 0.29, 0.81; P = .006) and DMFS (HR = 0.52; 95% CI: 0.28, 0.97; P = .039). Conclusion The post-NACT stage is more representative of prognosis than the pre-NACT stage in advanced-stage NPC patients, which suggests that major clinical decisions should be based on the post-NACT stage. © RSNA, 2016 Online supplemental material is available for this article.

Purpose To explore the value of combined modalities, including anatomical and functional magnetic resonance imaging (MRI), endoscopy and computed tomography (CT), for the assessment of tumor responses to definitive chemoradiotherapy (dCRT) in esophageal squamous cell carcinoma (ESCC). Methods Sixty-seven patients with locally advanced ESCC were enrolled. Tumor response (TR) was assessed two months after the completion of dCRT. Evaluation criteria according to combined modalities, including MRI, endoscopy and CT, were established and compared with traditional criteria based on CT and endoscopy. Progression-free survival (PFS)⩾12months was used as the reference standard, and the accuracy of the two criteria in response assessment was analyzed. Results Thirty-seven (55.2%) and 10 (14.9%) patients were considered to exhibit CR, as assessed by combined modalities and the traditional criteria, respectively. Using PFS⩾12months as a surrogate for CR, the sensitivity and specificity of the combined modalities were 82.4% and 88.9%, respectively, compared with 20.6% and 92.6% for the traditional criteria. TR assessed by combined modalities (CR vs. non-CR) was prognostic of PFS in univariate and multivariate analyses (Log-rank, P Conclusions Tumor responses assessed by the combined modalities of MR, endoscopy and CT seemed highly predictive of prognosis after dCRT in ESCC patients.

There is increasing evidence that cirrhosis may affect functional connectivity among various brain regions in patients prior to onset of overt hepatic encephalopathy (HE). However, most investigators have focused mainly on alterations in functional connectivity strengths, and the changes in functional connectivity density (FCD) are largely unknown. Here, we investigated alterations in resting-state FCD in patients with hepatitis B virus-related cirrhosis (HBV-RC) without overt HE. Totally, 31 patients with HBV-RC without overt HE and 30 age- and sex-matched healthy controls underwent resting-state functional MRI examinations. FCD mapping was employed to compute local and global FCD maps. Then, short-range and long-range FCD values were calculated and voxel-based comparisons were performed between the two groups. The HBV-RC group showed significant decreases in FCD, including decreased short-range FCDs in the bilateral middle cingulum gyrus/precuneus, the bilateral cuneus, and the left lingual gyrus/inferior occipital gyrus and decreased long-range FCD in the bilateral cuneus/precuneus. In addition, the decreased long-range FCD in the bilateral cuneus/precuneus in the HBV-RC group was related to performance on the psychometric hepatic encephalopathy score (PHES) test. These findings suggest aberrant functional connectivity density in cirrhotic patients prior to overt HE onset, which may provide better insight into understanding the pathophysiological mechanisms underlying the cirrhotic-related cognitive impairment.

BACKGROUND: To identify a radiomics signature to predict local recurrence in patients with non-metastatic T4 nasopharyngeal carcinoma (NPC). METHODS: A total of 737 patients from Sun Yat-sen University Cancer Center (training cohort: n = 360; internal validation cohort: n = 120) and Wuzhou Red Cross Hospital (external validation cohort: n = 257) underwent feature extraction from the largest axial area of the tumor on pretreatment magnetic resonance imaging scans. Feature selection was based on the prognostic performance and feature stability in the training cohort. Radscores were generated using the Cox proportional hazards regression model with the selected features in the training cohort and then validated in the internal and external validation cohorts. We also constructed a nomogram for predicting local recurrence-free survival (LRFS). FINDINGS: Eleven features were selected to construct the Radscore, which was significantly associated with LRFS. For the training, internal validation, and external validation cohorts, the Radscore (C-index: 0.741 vs. 0.753 vs. 0.730) outperformed clinical prognostic variables (C-index for primary gross tumor volume: 0.665 vs. 0.672 vs. 0.577; C-index for age: 0.571 vs. 0.629 vs. 0.605) in predicting LRFS. The generated radiomics nomogram, which integrated the Radscore and clinical variables, exhibited a satisfactory prediction performance (C-index: 0.810 vs. 0.807 vs. 0.753). The nomogram-defined high-risk group had a shorter LRFS than did the low-risk group (5-year LRFS: 73.6% vs. 95.3%, P

Heterogeneity of inhaled particle deposition in airways disease may be a sensitive indicator of physiologic changes in the lungs. Using planar gamma scintigraphy, we developed new methods to locate and quantify regions of high (hot) and low (cold) particle deposition in the lungs.Initial deposition and 24 hour retention images were obtained from healthy (n=31) adult subjects and patients with mild cystic fibrosis lung disease (CF) (n=14) following inhalation of radiolabeled particles (Tc99m-sulfur colloid, 5.4 μm MMAD) under controlled breathing conditions. The initial deposition image of the right lung was normalized to (i.e., same median pixel value), and then divided by, a transmission (Tc99m) image in the same individual to obtain a pixel-by-pixel ratio image. Hot spots were defined where pixel values in the deposition image were greater than 2X those of the transmission, and cold spots as pixels where the deposition image was less than 0.5X of the transmission. The number ratio (NR) of the hot and cold pixels to total lung pixels, and the sum ratio (SR) of total counts in hot pixels to total lung counts were compared between healthy and CF subjects. Other traditional measures of regional particle deposition, nC/P and skew of the pixel count histogram distribution, were also compared.The NR of cold spots was greater in mild CF, 0.221±0.047(CF) vs. 0.186±0.038 (healthy) (p0.005) and was significantly correlated with FEV1 %pred in the patients (R=-0.70). nC/P (central to peripheral count ratio), skew of the count histogram, and hot NR or SR were not different between the healthy and mild CF patients.These methods may provide more sensitive measures of airway function and localization of deposition that might be useful for assessing treatment efficacy in these patients.

To determine diagnostic performance of simple measurements on diffusion-weighted MR imaging (DWI) for assessment of complete tumour response (CR) after neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC) by signal intensity (SI) and apparent diffusion coefficient (ADC) measurements. Sixty-five patients with LARC who underwent neoadjuvant CRT and subsequent surgery were included. Patients underwent pre-CRT and post-CRT 3.0 T MRI. Regions of interest of the highest brightness SI were included in the tumour volume on post-CRT DWI to calculate the SIlesion, rSI, ADClesion and rADC; diagnostic performance was compared by using the receiver operating characteristic (ROC) curves. In order to validate the accuracy and reproducibility of the current strategy, the same procedure was reproduced in 80 patients with LARC at 1.5 T MRI. Areas under the ROC curve for identification of a CR, based on SIlesion, rSI, ADClesion, and rADC, respectively, were 0.86, 0.94, 0.66, and 0.71 at 3.0 T MRI, and 0.92, 0.91, 0.64, and 0.61 at 1.5 T MRI. Post-CRT DWI SIlesion and rSI provided high diagnostic performance in assessing CR and were significantly more accurate than ADClesion, and rADC at 3.0 T MRI and 1.5 T MRI. • Signal intensity (SI lesion ) and rSI are accurate for assessment of complete response. • rSI seems to be superior to SI lesion at 3.0 T MRI. • ADC or rADC measurements are not accurate for assessment of complete response.

To evaluate patterns of skull base invasion and its possible impact on tumor (T)-staging in nasopharyngeal carcinoma (NPC) using magnetic resonance imaging (MRI).838 consecutive newly diagnosed by biopsy proven and untreated patients with NPC underwent MRI. The skull-base invasion of NPC was classified according to their incidence from proximal sites to more distant sites surrounding the nasopharynx as: high (≥35%), medium (≥5-35%), and low (5%) groups. A retrospective analysis of data consisting of a 5-year follow-up was carried out. The skull base invasion was related to their tumor (T) staging and prognosis at the 5-year follow-up after treatment with definitive radiation therapy. In addition, a survival health-related quality of life (QOL), overall survival (OS), local relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) were also assessed among the three groups.The total incidence of skull-base invasion was 65.51% (549/838). The differences in T-stage distribution, and the total survival health-related QOL, among the three groups were statistically significant (χ(2)=160.45, p0.005; χ(2)=38.43, p0.005, respectively). The differences between any two of the three groups were also significant, except when the medium grade was compared to the low grade. Significant differences were observed with regard to 5-year OS (83.2%, 74.7%, 59.2%, p=0.000) and DMFS (95.0%, 88.0%, 88.0%, p=0.016); no significant difference was observed in LRFS (95.3%, 95.6%, 91.23%, p=0.450).The results indicate that medium and low group displayed similar findings of skull base invasion, and survival status. We, therefore, propose that patients in these two groups be grouped under T4 in the TNM classification that might have a bearing in implementing optimum treatment.

This study aimed to determine and quantitate the mammographic and sonographic characteristics in 13 cases of solid neuroendocrine breast carcinoma (NEBC) and to analyze the association of radiological findings with the clinical and histopathologic findings. The clinical data and imaging findings of 13 female patients with histologically confirmed solid NEBC were reviewed. Imaging data were evaluated by two radiologists for a consensual diagnosis. All patients presented with one palpable mass; only 1 experienced occasional breast pain, and 5 complained of fluid discharge. In 7 patients, the masses were firm and mobile. Regional lymph node metastasis was noted in only 1 patient. For the 10 patients who underwent mammography, 6 had a mass, 1 had clustered small nodules with clustered punctuate microcalcifications, 2 had asymmetric focal density, and 1 had solitary punctuate calcification. Most of the masses had irregular shape with indistinct or microlobulated margins. For the 9 patients who underwent ultrasonography (US), 9 masses were depicted, all of which were hypoechoic, mostly with irregular shape and without acoustic phenomena. Different types of acoustic phenomena were also identified. One patient had developed distant metastases during follow-up. NEBC has a variety of presentations, but it is mostly observed on mammograms as a dense, irregular mass with indistinct or microlobulated margins. Sonographically, it typically presents as an irregular, heterogeneously hypoechoic mass with normal sound transmission. Histories of nipple discharge and calcification observed using imaging are not rare.

The objective of this study is to evaluate the clinical, pathologic, and computed tomography (CT) and/or magnetic resonance imaging (MRI) findings of hepatic angiomyolipoma (HAML) and to improve the diagnostic efficacy of the tumor. Clinical, pathologic, and imaging findings were retrospectively evaluated in 18 patients with HAML. Two patients underwent both CT and MRI, ten underwent CT alone, and six underwent MRI alone. Unenhanced and contrast-enhanced examinations were performed in all patients. Imaging characteristics, such as the lesion location, lesion diameter, presence of early draining veins, attenuation/signal intensity of the lesions on imaging, and enhancement pattern were reviewed. There were 3 male and 15 female patients. HAML was seen as a well-defined, solitary mass on imaging with medium size (mean diameter, 5.9 cm). Fat was detected in ten patients. Calcification was noted in two patients and cystic degeneration was seen in one patient. Hepatic cirrhosis and capsule were not detected in all patients. The mean attenuation values exceeded 120 hounsfield units (HU) in 11 patients (91.7%). Peripherally decreasing enhancement rim as well as early draining vein was seen in 15 patients (83.3%). The early draining veins were all hepatic veins. Tumor vessels were noted in all patients. The presence of early draining vein, peripheral decreasing enhancement rim, and the absence of tumor capsule in the hypervascular hepatic tumor on CT and/or MRI together with normal alpha fetal protein may be helpful for the diagnosis of HAML in non-cirrhotic liver.

Background The purpose of this study was to investigate the incidence of retropharyngeal lymph node (RPLN) metastasis and to explore the associated risk factors using CT and MRI, to direct clinical radiotherapy in hypopharyngeal carcinoma (HPC). Methods The CT and MRI images of 218 patients with pathologically confirmed HPC were analyzed retrospectively. The chi-square test and logistic regression were used for statistical analysis. Results The incidence of RPLN metastasis in HPC was 17.0%, and the highest rate of 36.4% was found in pharyngeal wall carcinoma. None of the patients with N0 classification exhibited RPLN metastasis. Univariate and multivariate analyses demonstrated that primary tumor subsites, bilateral cervical lymph node metastasis, the number and size of cervical lymph nodes, and level V metastasis were significantly associated with RPLN metastasis. Conclusions Our findings demonstrated that primary carcinoma subsites and multiple metastatic cervical lymph nodes are the principal risk factors for RPLN metastasis. © 2012 Wiley Periodicals, Inc. Head Neck, 2013

Nasopharyngeal adenoid cystic carcinoma (NACC) is a rare malignancy with high local invasiveness. To date, there is no consensus on the imaging characteristics of NACC. To address this, we retrospectively reviewed 10 cases of NACC and summarized the magnetic resonance imaging (MRI) features. MR images of 10 patients with histologically validated NACC were reviewed by two experienced radiologists. The location, shape, margin, signal intensity, lesion texture, contrast enhancement patterns, local invasion, and cervical lymphadenopathy of all tumors were evaluated. Clinical and pathologic records were also reviewed. No patients were positive for antibodies against Epstein-Barr virus (EBV). The imaging patterns of primary tumors were classified into two types as determined by location, shape, and margin. Of all patients, 7 had tumors with a type 1 imaging pattern and 3 had tumors with a type 2 imaging pattern. The 4 tubular NACCs were all homogeneous tumors, whereas 3 (60%) of 5 cribriform NACCs and the sole solid NACC were heterogeneous tumors with separations or central necrosis on MR images. Five patients had perineural infiltration and intracranial involvement, and only 2 had cervical lymphadenopathy. Based on these results, we conclude that NACC is a local, aggressive neoplasm that is often negative for EBV infection and associated with a low incidence of cervical lymphadenopathy. Furthermore, MRI features of NACC vary in locations and histological subtypes.

Objective To summarize the CT and MRI features in a series of fifteen cases of Kimura's disease. Materials and methods The clinical data, CT and MRI findings of 15 patients with histologically proved Kimura's disease were retrospectively reviewed. All imaging data were consensually evaluated by two radiologists to determine the lesion location, number, morphology, margin, signal intensity or CT density, lesion texture, contrast enhancement pattern and involvement of adjacent structures. Results There were 14 male and 1 female, with peripheral blood eosinophilia in all 14 patients. 13 patients were presented with a painless mass. 13 patients had lesions located in the head and neck related to the major salivary glands. 1 patient had lesion in groin. Subcutaneous fat diffuse atrophy around the tumor site was found in 11 patients. 9 patients had solitary mass and 6 patients had multiple masses. Most masses were ill-defined, but no specific density or signal patterns were found. Most patients exhibited enlarged or obviously enhanced abnormal lymph nodes but without necrosis. Conclusion The characteristic distribution, morphology with enlarged draining lymphadenopathy, combined with the clinical features and laboratory examination enables a confident preoperative diagnosis of Kimura's disease.

Purpose The aim of the study was to investigate diffusion-weighted imaging as an early predictor in detection of response to chemoradiation in advanced cervical cancer. Methods Fourteen advanced cervical cancer patients treated with chemoradiation were enrolled in this study. All patients underwent conventional magnetic resonance imaging and diffusion-weighted imaging before the start of therapy, after 2 weeks of therapy, and at the completion of therapy. The tumor volumes and apparent diffusion coefficient (ADC) values of cervical lesions were measured at each examination. The correlation of ADC values and tumor regression was investigated. Results The mean ADC value of cervical lesion significantly increased as early as 2 weeks after chemoradiation. The ADC values before therapy did not significantly correlate with tumor response. The ADC values after 2 weeks of therapy did not show a significant correlation with tumor response. The change in ADC values after 2 weeks of therapy correlated with tumor response. Conclusions Diffusion-weighted imaging may provide an early surrogate biomarker for tumor response in advanced cervical cancers.

BACKGROUND AND OBJECTIVE Gastrointestinal stromal tumor (GIST) is one of the most common mesenchymal tumors of the digestive system. Imaging examination plays an important role in preoperative diagnosis and postoperative evaluation for it. This study was to describe the multi-slice spiral computed tomographic (MSCT) findings and pathologic features of GIST, and to analyze their correlation. METHODS MSCT and pathologic reports of 49 patients with 53 pathologically confirmed GIST lesions were reviewed and compared. RESULTS Of the 53 GIST lesions, 14 were at very low biological risk, 11 at low risk, ten at moderate risk and 18 at high risk; 36 (67.9%) were found in first visit by CT scans. On CT images, the GIST lesions with maximal diameter of > or =50 mm showed irregular shape, invasive growth, presence of cystic area and heterogeneous enhancement, and most of them were at high risk; the lesions with maximal diameter of

Understanding how inbreeding affects fitness is biologically important for conservation and pest management. Despite being a worldwide pest of many economically important cruciferous crops, the influence of inbreeding on diamondback moth, Plutella xylostella (L.), populations is currently unknown. Using age-stage-specific life tables, we quantified the inbreeding effects on fitness-related traits and demographic parameters of P. xylostella. Egg hatching rate, survival and fecundity of the inbred line significantly declined compared to those of the outbred line over time. The inbred P. xylostella line showed significantly lower intrinsic rate of increase (r), net reproduction rate (R0) and finite increase rate (λ) and increasing generation time (T). Inbreeding effects vary with developmental stages and the fitness-related traits can be profoundly affected by the duration of inbreeding. Our work provides a foundation for further studies on molecular and genetic bases of the inbreeding depression for P. xylostella.

The criteria for the diagnosis of metastatic retropharyngeal lymph nodes (RLNs) have not yet been resolved and are not included in the current edition of the American Joint Committee on Cancer (AJCC) staging system (seventh edition) for the staging of nasopharyngeal carcinoma (NPC). The aim of this study was to use MRI to identify an RLN size criterion that can accurately predict prognosis in patients with NPC.Eight hundred seventeen patients with newly diagnosed localized NPC were identified. All of the patients underwent MRI before treatment with definitive radiation therapy. All the MRI studies and medical records were reviewed retrospectively. Overall survival (OS), distant metastasis-free survival (DMFS), and local relapse-free survival (LRFS) were assessed using SPSS software (version 17.0).RLN size cutoffs of ≥ 5 mm and of ≥ 6 mm were used. There was no significant difference in OS (p = 0.216), DMFS (p = 0.081), or LRFS (p = 0.067) in patients with RLNs ≥ 5 mm and in those with RLNs5 mm. When 6 mm was used as a size cutoff, significant differences in OS (p = 0.000) and DMFS (p = 0.001) were identified; there was no significant difference observed for LRFS (p = 0.380).A minimum axial RLN diameter of 6 mm was a more accurate prognostic predictor in NPC patients with RLN metastases than 5 mm.

BACKGROUND AND PURPOSE: Lymphoepithelial carcinoma is a rare salivary gland lesion. We retrospectively reviewed CT and MR imaging features of salivary gland lymphoepithelial carcinoma to determine their imaging features and morphologic patterns. MATERIALS AND METHODS: The clinical data, CT, and MR imaging findings of 28 patients with histologically proved lymphoepithelial carcinoma of the salivary gland were retrospectively reviewed. Morphologic patterns of the lesions were categorized into 3 types on the basis of margin and shape. RESULTS: There were 17 men and 11 women with a mean age of 39.3 years; 96.4% of patients were positive for Epstein-Barr virus both on histologic staining and Epstein-Barr virus serology. Tumors were parotid in 18 patients, submandibular in 8 patients, sublingual in 1 patient, and palatal in 1 patient. Most tumors (57.1%) manifested as a partially or ill-defined mass with a lobulated or plaque-like shape. Homogeneous enhancement was found in 16 patients, while heterogeneous enhancement was found in 12, including 4 patients with intratumoral necrosis. Invasion into adjacent structures was found in 5 patients; 60.7% of patients exhibited abnormal lymph nodes, with nodal necrosis in 3 patients. CONCLUSIONS: The characteristic lobulated or plaque-like shape, with a partially or ill-defined margin, of a salivary gland mass associated with ipsilateral lymphadenopathy may suggest a preoperative diagnosis of lymphoepithelial carcinoma.

Purpose The aim of the study was to describe the clinical and computed tomography (CT) findings of primary lymphoepithelioma-like carcinoma (LELC) of the lung. Materials and methods The clinical data and CT findings of 35 patients with histologically proven primary LELC of the lung were retrospectively reviewed. The clinical data included age, sex, smoking history, signs and symptoms, tumor location, tumor size, stage, Epstein-Barr virus (EBV)-encoded small nuclear RNA status, treatment, and outcomes. Pretreatment CT scans of the thorax were used to access the tumor site, size, contour, density, vascular and/or bronchial involvement, relationship with pleura, and lymphadenopathy. Results The distinct clinical features of primary lung LELC include no significant predilection for sex, minimal association with a history of smoking, strong association with EBV in Asians, and a predilection for early or locally advanced stage of the disease. Most patients received complete resection and/or chemotherapy and radiotherapy. The 2- and 5-year overall survival rates for all patients were 81% and 51%, respectively. The common CT findings of primary lung LELC include peripheral nodules that have direct contact with the adjacent pleural surface, with a lesion density that is homogenous and sometimes heterogenous. Conclusions Radiologists should consider the diagnosis of LELC when encountering solitary peripheral pulmonary nodules that have direct contact with the pleural surface in EBV endemic areas, and an EBV-encoded small nuclear RNA test should be performed on histologic specimens of patients meeting these clinical criteria.

To evaluate the magnetic resonance diffusion-weighted imaging (DWI) in the detection of early ankylosing spondylitis and explore the manifestations of ankylosing spondylitis on whole body DWI (WB-DWI).A total of 16 patients with early ankylosing spondylitis (AS) and 18 patients with low back pain (LBP) were recruited. Subchondral bone marrow apparent diffusion coefficient (ADC) in bilateral ilium and sacrum along sacroiliac joints were compared. An independent sample t-test (SPSS 16.0, SPSS, Chicago, III) was utilized to analyze the ADC value differences between groups. P0.05 denoted statistical significance. The mean ADC values of focal lesions in AS patients were also measured. Whole body diffusion weighted imaging was performed in additional 8 clinical confirmed AS patients and analyzed with the techniques of maximum intensity projection (MIP) and multiplanar reconstruction (MPR) in comparison with conventional MRI images to investigate the detectability of AS lesions with whole body DWI.Mean ADC values in 16 AS patients were (0.51 ± 0.13)×10(-3)mm(2)/s in ilium and (0.49 ± 0.17)×10(-3)mm(2)/s in sacrum. Mean ADC values in 18 LBP patients were (0.32 ± 0.06)×10(-3)mm(2)/s in ilium and (0.31 ± 0.08)×10(-3)mm(2)/s in sacrum. The ADC value in AS patients were statistically significantly greater than those in ilium and sacrum of LBP patients. Whole body DWI detected abnormalities in 8 AS patients within bilateral sacroiliac joints and other sites corresponding to the clinical symptoms of patients. The mean ADC values of focal lesions of this patient cohort were (1.31 ± 0.38)×10(-3)mm(2)/s in sacrum and (1.18 ± 0.27)×10(-3)mm(2)/s in ilium.Subchondral marrow ADC values along sacroiliac joints allow the differentiation of patients with early AS from LBP patients. In conjunctions with such post-processing techniques as MIP and MPR, WB-DWI allows a comprehensive assessment of AS patients to guide treatment, evaluate prognosis and follow therapeutic responses.

Purpose Tuberculosis is uncommon in the nasopharynx. The purpose of this study was to investigate the CT and MRI features of 36 cases of tuberculosis in this area. Materials and methods CT (n = 15) and MRI (n = 21) scans from 36 patients with histologically proved tuberculosis of the nasopharynx were reviewed by two experienced radiologists, paying particular attention to the lesions’ distribution, location, extent, size, internal architecture, pattern, and degree of enhancement, and cervical lymphadenopathy. Results Twenty-nine patients exhibited a polypoid mass pattern and seven had diffuse mucosal thickening. The roof of the nasopharynx was involved in all cases. The mean size of the lesions was 11.4 mm. Striped pattern was detected in 19 cases. Adjacent muscle invasion or bone destruction was not detected. Heterogeneous enhancement was detected in all patients, and necrosis in the nasopharyngeal lesions was detected in 16 cases. Poor, moderate, and marked enhancement was detected in one, 27, and eight cases, respectively. Thirty-four patients had involvement of the cervical lymph nodes. Twenty-two and 28 cases were associated with bilateral lymphadenopathy or necrosis, respectively. The retropharyngeal lymph node was the most commonly involved site (94.1%). Conclusion The presence of necrosis and striped pattern in nasopharyngeal lesions, site predilection, no invasion of regional structures, and central necrosis with peripheral rim enhancement of cervical lymphadenopathy may suggest the diagnosis of nasopharyngeal tuberculosis.

To identify the locoregional extension of hypopharyngeal carcinoma (HPC), particularly the invasion of the nasopharynx and skull base, and metastasis of level VI and retropharyngeal lymph node (RPLN) by investigating computed tomography (CT) and magnetic resonance (MR) images; together with the radiotherapy target of HPC.CT and MR images of 186 patients with pathologically confirmed HPC between Aug 2000 and Dec 2010 were analyzed retrospectively. We used the χ(2) test and logistic regression to analyze local invasion and regional spread and to determine their relationships.Of the 186 patients, there was only one case of invasion of the nasopharynx without skull base involvement. The rate of regional node metastasis was 79%. There was no significant relationship between T stage and lymph node metastasis (P = 0.1). Level IV metastasis (P = 0.001), RPLN metastasis (P = 0.041) and esophageal invasion (P = 0.003) were significantly correlated with level VI metastasis. Primary tumor subsite (P = 0.024), bilateral cervical node metastasis (P0.001) and size of cervical nodes (P = 0.01) significantly contributed to the occurrence of RPLN metastasis.The locoregional spread of HPC occurs via certain routes. It is potentially unnecessary to routinely and prophylactically irradiate the nasopharynx and skull base. Patients with early stage HPC should receive bilateral cervical prophylactic irradiation. The decision regarding the administration of prophylactic irradiation to the level VI and RPLN areas should be according to the relative risk factors.

This study was focused on the serial changes in magnetic resonance images (MRI) of the skull-base bone that occur after endoscopic nasopharyngectomy in patients with local recurrent nasopharyngeal carcinoma (rNPC).Nine patients with histologically proven rNPC were enrolled in this study. Two experienced radiologists independently reviewed all presurgical and postsurgical MR images for each patient.At 36 sites on the skull base, the MRI signal underwent a change after surgery, which took the form of a heterogeneous pattern of hypointense regions with moderate contrast enhancement on T1WI. The onset of changes ranged between 2 weeks and 3 months after surgery. For 21 of the sites, the changes subsided over the course of follow-up, while in 6 they remained stable. At 9 sites, the alteration MRI signal became more pronounced with time. Changes were more common on the homolateral side of the skull base with respect to the recurrent tumor (P0.05). The skull-base bone adjacent to the resection boundary had a higher incidence of signal change than nonadjacent areas (P0.05).MRI changes in the skull base bone, having a number of distinguishing characteristics, appear to be a common sequel to endoscopic nasopharyngectomy for rNPC.

Aim To investigate the radiological findings of head and neck radiation-induced sarcomas (RISs) following radiotherapy for nasopharyngeal carcinoma (NPC). Materials and methods Fifty-nine patients with RISs were identified. Imaging characteristics on computed tomography (CT) and magnetic resonance imaging (MRI), including lesion location, extent, size, margin, internal architecture, pattern, and degree of enhancement, together with patient characteristics at NPC diagnosis and latency periods, were reviewed. Results The study included 20 women and 39 men, with a median age of 49 years (range 30–71 years). The median latency was 9 years (range 3–37 years). The median radiation dose at the site of RIS was 66 Gy (range 44–78 Gy). The most common histological RIS types were fibrosarcoma (44.1%) and osteosarcoma (30.5%). The most common RIS sites were the paranasal sinuses and the nasal cavity (39%), the neck (16.9%), and the mandible (15.3%). The mean size was 5.1 cm (range 1.2–8.6 cm). Overall, 78% of lesions extended to adjacent spaces and 66.1% were accompanied by bone destruction. Heterogeneous density/signal intensity before and after enhancement was seen in all lesions on imaging. Marked lesion enhancement was noted in 49 cases (76.3%). Conclusions The radiologist should be aware of the different sites at which RISs occur and the radiological appearance of the wide variety of RIS subtypes. Careful imaging follow-up is necessary for early detection of RISs in patients with NPC after radiotherapy.

How an insect evolves to become a successful herbivore is of profound biological and practical importance. Herbivores are often adapted to feed on a specific group of evolutionarily and biochemically related host plants, but the genetic and molecular bases for adaptation to plant defense compounds remain poorly understood. We report the first whole-genome sequence of a basal lepidopteran species, Plutella xylostella, which contains 18,071 protein-coding and 1,412 unique genes with an expansion of gene families associated with perception and the detoxification of plant defense compounds. A recent expansion of retrotransposons near detoxification-related genes and a wider system used in the metabolism of plant defense compounds are shown to also be involved in the development of insecticide resistance. This work shows the genetic and molecular bases for the evolutionary success of this worldwide herbivore and offers wider insights into insect adaptation to plant feeding, as well as opening avenues for more sustainable pest management.

Advanced parapharyngeal space (PPS) involvement showed stronger prognostic value than PPS involvement. The classification of PPS involvement proposed by Min or Sham was the most appropriate classification for parapharyngeal extension in nasopharyngeal carcinoma (NPC). The degree of tumor extension into the PPS should be considered in future TNM staging revisions.This study was conducted to evaluate the prognostic significance of the various classifications for PPS involvement in patients with NPC.From January to July 2000, a total of 176 patients with pathologically diagnosed NPC were prospectively enrolled in this study. The extent of PPS involvement was examined by contrast-enhanced computed tomography (CT) scan and graded according to the four previously reported classifications (Min, Sham, Xiao, and Heng).The incidence of PPS involvement was 81.8%. The 5-year overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and local relapse-free survival rates (LRFS) of the patients with and without PPS involvement were 68.1% and 90.2% (p = 0.010), 66.1% and 87.2% (p = 0.013), 76.7% and 93.6% (p = 0.032), and 84.9% and 93.1% (p = 0.220), respectively. Multivariate analysis showed that PPS involvement (yes vs no) was not an independent prognostic factor. However, graded PPS involvement was an independent factor affecting the prognosis of NPC. When the four classifications were included in a Cox model, it was shown that PPS involvement based on Min's classification was an independent factor for OS (p = 0.001). PPS involvement based on Sham's classification was an independent factor for PFS (p = 0.010) and DMFS (p = 0.009).

To summarize the distinct imaging features of different subtypes of primary nasopharyngeal non-Hodgkin's lymphomas (NHLs).Clinical data and magnetic resonance imaging findings of 71 patients with histologically proven primary nasopharyngeal NHLs were retrospectively reviewed. The tumor distribution, signal intensity, lesion texture, contrast enhancement properties, extra-chamber involvement, regional structure invasion, and cervical lymphadenopathy were evaluated and compared between different subtypes of NHLs.Of the patients, 70.4% had B-cell lymphomas; 64.8% had symmetrical and diffuse involvement of nasopharynx walls; and 19.7% had superficial ulcerations. Extra-chamber involvement and regional structure invasion occurred in most patients. The frequency of neck node involvement was up to 83.10%; 62.7% of them were bilateral involvement. Patients with T-cell or nature killer/T-cell NHLs had a higher incidence of superficial ulcerations, nasal cavity, and paranasal sinus invasion than B-cell NHLs (P.05). Patients with B-cell NHLs had a higher incidence of cervical lymphadenopathy specifically in Level VA and parotid region than T-cell or nature killer/T-cell (NK/T-cell) NHLs (P.05).Primary nasopharyngeal NHLs had some characteristic imaging features and different subtypes of nasopharyngeal NHLs had some distinct imaging features.

To evaluate the temporal lobe injury (TLI) in nasopharyngeal carcinoma (NPC) patients who had received intensity modulated radiotherapy (IMRT) and to assess the dosimetric parameters associated with TLI.Forty of 870 patients were diagnosed with TLI after IMRT, the clinical and dosimetric characteristics of these TLI were analyzed.A total of 4.6% (40/870) patients have developed TLI. However, TLI is not observed in T1-2 patients, the incidences are 3.1% and 13.4% in T3 and T4 patients respectively. The Dmax (maximum point dose, Gy) and D1 cc (the dose delivered to the 1 cubic centimeter volume, Gy) in injured temporal lobes (TLs) are greater than that in normal TLs (P0.01). TLI is not observed in TLs with Dmax64 Gy or D1 cc52 Gy, and the 5-year incidence of TLI in patients with Dmax 64-68 Gy or D1 cc 52-58 Gy is5.0%. A linear regression demonstrates a 2.6% augment of TLI per Gy of Dmax exceeding 64 Gy and a 2.5% augment of TLI per Gy of D1 cc exceeding 52 Gy; TLI is correlated with Dmax (r=0.89, P0.01) and D1 cc (r=0.87, P0.01) respectively.The incidence of TLI is relatively high, especially for patients with advanced T-stage NPC, and correlated with Dmax and D1 cc. IMRT with Dmax68 Gy or D1 cc58 Gy in TLs is relatively safe.

To evaluate bony changes in the skull base after radiotherapy by computed tomography (CT) and their correlation with local recurrence in patients with nasopharyngeal carcinoma (NPC) without previous involvement of the skull base.Retrospective study.Sun-Yat Sen University Cancer Center.The records of 80 patients with NPC during the period from January 1992 to December 2005 were reviewed. All patients had been treated with radical radiotherapy or chemoradiotherapy at standard doses and were followed up with plain and contrast-enhanced CT every 6 months for 45.5 (range 12-108) months.The types, areas, time of the first occurrence after radiotherapy and development of the postradiation bony changes of the skull base, and local recurrence rates of NPC were measured.Eighteen patients (22.5%) had sclerosis in some area of the skull base, and the sclerosis in 5 (27.8%) of these patients changed into osteoporosis in 1 to 5 years after its appearance. Seventeen patients (21.3%) had osteolysis. The local recurrence rate of patients with osteolysis was observed to be significantly higher than that of patients with sclerosis (p.0001).The appearance of osteolytic changes in the skull base during follow-up of patients with NPC who had normal skull base morphology before treatment was associated with tumour recurrence.

To evaluate the distributions of primary nasopharyngeal carcinoma (NPC) and the patterns of skull base involvement in NPC patients using magnetic resonance imaging (MRI).After the approval of institutional review board and informed consent, 838 consecutive newly-diagnosed and untreated NPC patients were examined by MRI. Their MR images were reviewed by two independent radiologists.Among all cases, the incidence rates of superior side and post-superior side involvement were 98.57% (826/838) and 98.21% (823/838) respectively. The differences were not significant between these two sides (P0.05). Lateral side erosion was demonstrated in 784 (93.56%) cases. Posterior side was involved in 391 (46.66%) cases. The total incidence rate of skull base involvement was 65.51% (549/838). According to the anatomic site, the pathways of skull base involvement were classified into 5 spreading routes: anterior; superior; super-lateral; super-anterior and super-posterior. According to the incidence rates and the results of chi-square test, the anatomic sites around the nasopharynx were classified into three groups of risk grades: high-risk (≥ 35%), medium-risk (≥ 5% - 35%) and low-risk (5%).Skull base involvement of NPC spreads stepwise from proximal site to more distal sites. The area of skull base involvement in NPC is classified into high-grade, medium-grade and lower-grade groups respectively. The high and medium-grade groups are related with T3 stage while the lower-grade group T4 stage. Thus T3 stage should be subdivided into T3a and T3b. These schemes may be useful in a more accurate NPC staging and a delineation of clinical target volume for radiotherapy in NPC patients.

Primary AT/RT is a rare highly malignant tumor of the CNS, usually occurring in children younger than 5 years of age. The objective of this study was to characterize the CT and MR imaging findings in a series of 5 adult patients with pathologically proved AT/RT. All 5 AT/RTs were supratentorial. In 2 patients who underwent nonenhanced CT, the tumors appeared isoattenuated, and 1 of the 2 tumors contained calcifications. Solid portions of the tumors on MR imaging were isointense on T1-weighted, T2-weighted, and FLAIR images, and 1 case showed restricted diffusion on DWI. The tumors also demonstrated a bandlike rim of strong enhancement surrounding a central cystic area on contrast-enhanced T1-weighted imaging. One tumor was associated with destruction of the calvaria. Although AT/RTs can have nonspecific findings, the tumors in our series were large and isointense on T1-weighted, T2-weighted, and FLAIR images with central necrosis and prominent rim enhancement.

Purpose To describe differences in the primary tumour and distribution of cervical lymphadenopathy for cases of nasopharyngeal carcinoma (NPC) and nasopharyngeal non-Hodgkin's lymphoma (NPNHL) using magnetic resonance (MR) imaging. Materials and methods MR images of patients with NPC ( n =272) and NPNHL ( n =118) were independently reviewed by two experienced radiologists. Results NPC had a higher incidence of tumour invasion associated with the levator and tensor muscles of the velum palatine, the longus colli and medial pterygoid muscles, the base of the pterygoid process, the clivus, the base and greater wing of the sphenoid bone, the petrous apex, the foramen lacerum, the foramen ovale, the hypoglossal canal, and intracranial infiltration. In contrast, NPNHL had a higher incidence of tumour invasion associated with the hypopharynx, the palatine and lingual tonsils, as well as the ethmoid and maxillary sinuses. NPNHL also had a higher incidence of extensive and irregular bilateral lymphadenopathy, and lymphadenopathy in the parotid. Conclusions NPC more often involved an unsymmetrical tumour with a propensity to invade both widely and deeply into muscle tissue, the fat space, the neural foramen, and the skull base bone. In contrast, NPNHL tended to be a symmetrical and diffuse tumour with a propensity to spread laterally through the fat space and along the mucosa to the tonsils of the oropharynx and hypopharynx. These differences facilitate a differentiation of these diseases using MR images, and enhance our understanding of the biological behavior of these malignant tumours of the nasopharynx.

To investigate the imaging features, clinical manifestations and pathological characteristics of solitary fibrous tumors (SFT).The clinicopathological manifestations and medical imaging findings were analyzed retrospectively in 27 patients with surgically confirmed SFT.The SFTs originated from different parts of the body, including 18 in the chest, 4 in the abdomen, 1 in the lumboscral area, 3 in the pelvis, and 1 in the left shoulder. Twenty-three cases were found by CT scan, among which there were 16 benign diseases, presented with well-defined round or elliptic margins, with homogeneous attenuation and clearly surrounding; 6 malignant cases with unclear demarcations, invasive surrounding, heterogeneous attenuation due to calcification and/or irregular necrosis, and 1 junctional case with well-defined margins, which was enlarged during follow-up. There were 4 SFTs scanned by MRI with clear margin and homogeneous or heterogeneous signal intensity. All of the 4 cases were isointense or hyperintense to muscle on T1-weighted images, and were hyperintense on the T2-weighted images. All tumors showed heterogeneously intense enhancement with geographic pattern. Immunohistochemical staining showed that CD34-positive was 81.5%, vimentin (100.0%), CD99 (100.0%) and bcl-2 (96.3%), as well as negative CK (100.0%) and S-100 (96.3%).The location of SFT is varying. Though its clinical manifestations vary, the diagnosis is depended on pathology and immunohistochemistry. There are certain specific features related to SFTs on CT or MRI. These imaging techniques may serve to provide helpful information as to the location and vicinal anatomic structure of the tumor, which is of substantial importance for planning surgery.

The aim of this study was to evaluate the value of diffusion weighted imaging (DWI) in the diagnosis of patients with breast diseases.Fifty-three consecutive patients were scanned with GE signa HDx 1.5 T magnetic resonance system equipped with 8-channel breast coil. DWI was scanned by SE-EPI sequence in b values of 500 s/mm(2) and 800 s/mm(2), respectively. The apparent diffusion coefficients (ADC) of these lesions were measured. The mean apparent diffusion coefficients (ADC) of these lesions were calculated in b values of 500 s/mm(2) and 800 s/mm(2), respectively. These lesions' ADC value (rADC) was counted respectively and the result of the rADC was equal to the lesion's ADC divided by the ADC of the ipsilateral normal breast tissue. Threshold of ADC and rADC for differential diagnosis was acquired by ROC (receiver operating characteristic curve) analysis. Different imaging technologies were evaluated emphasizing their sensitivity, specificity and accuracy.Sixty-six lesions of 53 cases were confirmed by pathology, including 39 malignant lesions and 27 benign lesions. (1) b = 500 s/mm(2), the threshold of ADC value was 1.435 x 10(-3) mm(2)/s, with a sensitivity of 82.1% and a specificity of 81.5%. The threshold of rADC value was 0.62, with a sensitivity of 76.9% and a specificity of 100%. (2) b = 800 s/mm(2), the threshold of ADC value was 1.295 x 10(-3) mm(2)/s, with a sensitivity of 79.5% and a specificity of 81.5%. The threshold of rADC value was 0.71, with a sensitivity of 89.7% and specificity of 88.9%. (3) The area under the ROC curve was increased for the four diagnostic indicators (ADC(500), ADC(800), rADC(500), rADC(800)).DWI spends short time, and it doesn't need contrast material. ADC value and rADC value have a high sensitivity and specificity as a diagnostic indicator. DWI is helpful in improving the specificity of MR and may become one of valuable conventional procedures for breast tumor diagnosis.

It is difficult to discriminate progressive gastric cancer and gastric lymphoma by CT imaging, because incrassate gastric wall, lump in gastric cavity, confined gastric cavity, intumescent lymph node, and distant metastasis can be displayed in both of them. This study was to compare the CT findings between gastric cancer and gastric lymphoma to improve diagnosis of gastric tumors, especially for gastric lymphoma.CT images of 27 patients with pathologically proved progressive gastric cancer and 25 patients with pathologically proved gastric lymphoma were reviewed. Tumor location, appearance, scope of involvement, gastric wall thickness, mucous membrane, mucosal fold, serosa membrane, necrosis, enhancement degree and uniformity, involvement of other organs, and abdominal lymph nodes were observed.White line sign was observed in 23 cases (85.2%) of gastric cancer, but not in the 25 cases of gastric lymphoma. The extent of white line sign in gastric cancers was larger in portal vein phase than in arterial phase. Enhancement degree outside the white line was higher in portal vein phase than in arterial phase in 13 cases (48.1%) of gastric cancer. The extent of involved gastric wall was smaller than 50% of the whole gastric wall in all the 27 cases of gastric cancer, while it was larger than 75% in 23 cases (85.2%) of gastric lymphoma. Gastric mucous membrane ulcer was found in all of the 27 cases (100%) of gastric cancer, while it was found in only 1 case (4.0%) of gastric lymphoma. Intumescent lymph nodes in two or more areas were found in 11 cases (40.0%) of gastric lymphoma, but not in gastric cancer. Intumescent lymph nodes in the retroperitoneal space below renal hilum were found in 8 cases (32%) of gastric lymphoma, but not in gastric cancer.There are some different CT features between gastric cancer and gastric lymphoma, such as white line sign, gastric mucous membrane ulcer, extent of involved gastric wall, location of intumescent lymph nodes surrounding the stomach and in retroperitoneal space below renal hilum, and so on, which could be helpful in differential diagnosis of these two diseases.

To assess the value of white matter fiber tractography based on magnetic resonance diffusion-tensor imaging (MR-DTI), a new noninvasive technique that helps estimate the structural connectivity of the brain, in understanding the anatomy of the white matter fiber tract.Six consecutive volunteers received MR-DTI examination using a GE 1.5T Sign CV/I whole-body MR system and version 2.0 Functool software for image processing. The protocol included T1WI for localization and single-shot echo-planner diffusion tensor imaging of the entire brain in axial, sagittal, and /or coronal sections.White matter fiber tracts imaged by MR-DTI were consistent with known white matter fiber anatomy. The major fiber tracts were well observed in all the cases. The tracts visualized included the corpus callosum, anterior commissure, uncinate fasciculus superior and inferior longitudinal fascicules, inferior occipito-frontal fasciculus, internal capsule and corona radiate.A set of detailed white matter fiber anatomy maps of the normal brain is obtained by means of single-shot echo-planner diffusion tensor imaging at high resolution. This technique allows rapid visualization of the white matter tracts in vivo, and provides a new reliable means for studying fiber connectivity in the brain.

Primary brain lymphoma, a rare tumor, is often misdiagnosed as malignant glioma or metastases before operation. A definite preoperative diagnosis of primary brain lymphoma is of great significance because of its sensitive to chemotherapy and irradiation. This study was to analyze the magnetic resonance imaging (MRI) features of primary brain lymphoma to improve the diagnosis and differential diagnosis accuracy.MRI findings in 9 patients with pathologically proved primary brain lymphoma were analyzed for the number of lesions, tumor site, signal intensity, peritumoral edema, mass effect and contrast enhancement patterns.Of the 9 patients, 8 had supratentorial solitary lesion, and 1 had supratentorial and infratentorial solitary lesion. On plain MRI, 8 lesions were hypo-intense and 1 iso-intense on T1WI, while 6 displayed iso-intense, 1 hypo-intense and 2 slightly hyper-intense on T2WI. Necrosis was seen in 2 lesions. The peritumoral edema was mild in 5 lesions, moderate in 3 lesions, and severe in 1 lesion. On Gd-DTPA-enhanced MRI, 4 lesions displayed obvious homogeneous mass-like enhancement, 3 lobular enhancement and 2 ring-like enhancement.Primary brain lymphoma in immunocompetent patients has typical MRI features. Correct diagnosis could be made before operation when imaging findings are considered together with clinical data.

It's difficult to distinguish peripheral primitive neuroectodermal tumor (PNET) from other small round cell tumors such as Ewing's sarcoma by histological examination. This study was to analyze the CT and MRI features of peripheral PNET.The CT and MRI records of 7 patients with pathologically proved peripheral PNET were reviewed.The tumors were located in the left ala nasi, right lower jaw bone, left chest wall, right chest wall, left spermatic cord, paraspinal, and lumbar vertebral canal. The tumors in soft tissue showed resembled non-calcified, ill-defined soft tissue masses with cystic or necrotic areas on CT images, with heterogeneous enhancement on contrast images. The tumors in the bone showed lytic lesions with large soft tissue masses on CT images. The tumors in the paraspinal and vertebral canal showed well-defined soft tissue masses without involving cord and cauda equine on MRI, and showed isointensity or hypointensity on T1WI and isointensity or hyperintensity on T2WI.The imaging features of peripheral PNET are non-specific. CT and MRI are useful in delineating the extent, finding distant metastasis, predicting respectability and monitoring treatment of peripheral PNET.

The clinical classification of nasopharyngeal carcinoma (NPC) depends mainly on the materials of medical imaging. This study was to investigate the application of magnetic resonance imaging (MRI) to the clinical classification of NPC.One hundred patients with NPC confirmed by pathohistology received MRI and computed tomography (CT) within 15 days before treatment from May 2002 to Jun. 2005. The patients included 74 men and 26 women with a median age of 46 (21-60). The detection rates of involved sites by MRI and CT were calculated and compared using Chi(2) test. The clinical classification was performed according to 92'staging system of China. The constituent ratios of cases at different T, N, and clinical stages classified by MRI and CT were analyzed by Chi(2) test.The detection rates of skull base bone destruction and retropharyngeal lymph node involvement were significantly lower by CT than by MRI (31.0% vs. 56.0%, Chi(2)=12.715, P=0.000; 40.0% vs. 55.0%, Chi(2)=4.511, P=0.034). The constituent ratio of cases at T1-T4 stages classified by MRI was different from that classified by CT (Chi(2)=8.339, P=0.039), but there was no difference in N staging (Chi(2)=0.275, P =0.965) and clinical classification (Chi(2)=5.525, P=0.137).MRI is more sensitive than CT in detecting skull base bone destruction and retropharyngeal lymph node involvement of NPC. MRI may upstage T classification, tends to upstage clinical classification, and has no influence on N classification of NPC.

The helical double-phase CT scan imaging features of hepatocellular carcinoma (HCC) overlap those of other hepatic lesions. This study was to investigate the helical double-phase CT scan imaging features of HCC to improve diagnosis accuracy.Double-phase CT data and pathologic data of 52 HCC patients, received resection in Cancer Center of Sun Yat-sen University from Dec. 2000 to Dec. 2002, were analyzed. The double-phase CT features of HCC lesions were summarized. The pathology of false-positive lesions was analyzed.CT scan showed 56 lesions in the 52 patients: 51 were cancer lesions, including 49 HCC lesions and 2 mixed lesions of HCC and cholangioma, 5 were false-positive lesions. Arterial phase of these HCC lesions showed obvious heterogeneous enhancement, and the portal vein phase showed heterogeneous low dense. Necrosis was seen in all massive lesions, but was seldom seen in nodular and small lesions. Most lesions had clear borders and amicula. The pathologic diagnoses of the 5 false-positive lesions were hepatic cirrhosis with hepatocellular nodular hyperplasia, regenerative nodule, hepatic cirrhosis, bile duct calculus companied with inflammatory reaction, and fibrosis hyperplasia.Helical double-phase CT scan can be used to diagnose typical HCC lesions. There are no obvious differences in helical double-phase CT scan between HCC lesions and false-positive lesions. The diagnosis of HCC must be based on clinical information, follow-up or biopsy.

Blood flow patterns with CT perfusion imaging (CTPI) had been innovated to delineate abnormal hemodynamic lesions in the liver, brain, and kidney. This study was to evaluate the blood flow patterns of pulmonary masses by CTPI, and determine the value of CTPI in differential diagnosis among benign, malignant, and inflammatory masses.Fifty-two patients with previously diagnosed pulmonary masses (37 with malignant masses, 7 with benign masses, and 8 with inflammatory masses) underwent dynamic CTPI. Time-density curves (TDC) of artery, vein, and pulmonary masses as well as mass perfusion images and parameters including perfusion volume (PV), peak height (PH), mean transit time (MTT) and blood volume (BV) were obtained by Phlips CT-perfusion software.The values of PV, PH, and BV were significantly higher in malignant masses and active inflammatory masses than in benign masses [(27.63+/-15.06) ml.min(-1).ml(-1) and (30.80+/-20.33) ml.min(-1).ml(-1) vs. (11.81+/-3.74) ml.min(-1).ml(-1), (28.46+/-12.07) Hu and (32.15+/-15.89) Hu vs. (10.41+/-3.77) Hu, (21.64+/-10.97) ml/100 g and (28.38+/-14.55) ml/100 g vs. (10.61+/-5.33) ml/100 g, P0.01]. However, the differences of MTT among malignant, inflammatory, and benign masses were not significant [(28.39+/-21.66) s, (25.91+/-14.57) s, and (29.86+/-13.57) s, P=0.928]. No significant differences in the 4 parameters were found between malignant and inflammatory masses. When PV20 ml.min(-1).ml(-1) and pH15 Hu were set as a diagnostic threshold (excluded active inflammatory masses), the sensitivity, specificity, and accuracy were 91.9%, 100%, and 84.1%, respectively.CT perfusion imaging provides quantitative information about blood flow patterns of pulmonary masses and is an applicable diagnostic method for differentiating pulmonary masses.

Background and Purpose Increasing evidence suggests that cirrhosis may affect the connectivity among different brain regions in patients before overt hepatic encephalopathy (OHE) occurs. However, there has been no study investigating the structural reorganization of these altered connections at the network level. The primary focus of this study was to investigate the abnormal topological organization of the structural network in patients with hepatitis B virus-related cirrhosis (HBV-RC) without OHE using structural MRI. Methods Using graph theoretical analysis, we compared the global and regional topological properties of gray matter structural networks between 28 patients with HBV-RC without OHE and 30 age-, sex- and education-matched healthy controls. The structural correlation networks were constructed for the two groups based on measures of gray matter volume. Results The brain network of the HBV-RC group exhibited a significant decrease in the clustering coefficient and reduced small-worldness at the global level across a range of network densities. Regionally, brain areas with altered nodal degree/betweenness centrality were observed predominantly in association cortices (frontal and temporal regions) (p < 0.05, uncorrected), including a significantly decreased nodal degree in the inferior temporal gyrus (p < 0.001, uncorrected). Furthermore, the HBV-RC group exhibited a loss of association hubs and the emergence of an increased number of non-association hubs compared with the healthy controls. Conclusion The results of this large-scale gray matter structural network study suggest reduced topological organization efficiency in patients with HBV-RC without OHE. Our findings provide new insight concerning the mechanisms of neurobiological reorganization in the HBV-RC brain from a network perspective.

Thymic epithelial tumors have a broad spectrum of biologic and morphologic features. This study was to assess the CT features of various subtypes of thymic epithelial tumors on the basis of the 1999 World Health Organization (WHO) classification.CT features of thymic epithelial tumors in 94 patients were retrospectively analyzed. All cases were confirmed histologically according to the 1999 WHO classification, including 7 cases of type A, 24 cases of type AB, 16 cases of type B1, 13 cases of type B2, 16 cases of type B3, and 18 cases of type C.In the 94 cases, the long- and short-axis diameters of type A and type AB tumors were significantly shorter than those of type C tumors (P0.05). All type A tumors had smooth contours, type A, AB, and B1 tumors were likely to have smooth contours (P0.05), while type B3 and C tumors were likely to have irregular contours (P0.05). Type A tumors had less necrotic areas than any other types (P0.05). Multiple calcifications were more frequently seen in type B2, B3, and C tumors than in type A, AB, and B1 tumors (P0.05). Homogeneous enhancement was more frequently seen in type A, AB, B1, and B2 tumors than in type B3 and C tumors (P0.001). Type B3 and C tumors significantly preferred to infiltrate into mediastinal fat than any other types (P0.05).Though CT features of different subtypes of thymic epithelial tumors according to WHO classification are overlapped, short diameter, smooth contour, round shape, homogeneous density, and homogeneous enhancement are most suggestive for type A tumor; large diameter, irregular contour, necrosis and multiple calcifications in the lesion, heterogeneous enhancement, mediastinal fat infiltration, and great vessel infiltration are most suggestive for type B3 and C tumors.

Mediastinal lymph node staging in non-small cell lung cancer (NSCLC) is important to choose standard treatment plan and estimating prognosis. This study was to evaluate the clinical value of spiral CT in staging mediastinal lymph node in NSCLC through comparing spiral CT findings with corresponding pathology.A total of 89 patients with pathologically proven NSCLC received spiral CT and mediastinoscopic biopsy. The spiral CT findings and corresponding pathologic findings in staging mediastinal lymph node were compared. The sensitivity, specificity, and accuracy of diagnosing mediastinal lymph node metastasis were calculated.Compared with corresponding pathologic results, the overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of mediastinal lymph node staging with spiral CT were 58.9%, 70.0%, 60.5%, 68.6%, and 65.2%, respectively. The accuracy and specificity of spiral CT was relatively low in staging 4R, 5, 6, 7 lymph node groups; the false negative and false positive rates were relatively high in staging 4R, 7 lymph node groups.Spiral CT is a non-invasive clinical examination which may be used in staging mediastinal lymph node in NSCLC; however, there exists false negative and false positive rates. It should be combined with other investigations, such as mediastinoscopy, to assess a more accurate mediastinal lymph node staging.

At present, the detection of retropharyngeal lymph node (RLN) metastasis in nasopharyngeal carcinoma (NPC) mainly depends on imaging, but the diagnosis criteria are controversial. Recently, the 18F-fluoro-2-deoxy-D-glucose positron emission tomography ((18)FDG-PET-CT) has been widely applied in diagnosing cancer. This study was to evaluate CT, MRI, and (18)FDG-PET-CT in detecting RLN metastasis of NPC, and explore the imaging diagnosis criteria.From Dec. 2003 to Aug. 2005, 53 consecutive patients with NPC treated in Cancer Center of Sun Yat-sen University were enrolled. Contrast enhanced CT, MRI, and (18)FDG-PET-CT were performed on bilateral RLNs of the patients within 10 days before treatment. The diagnosis criteria of RLN metastasis for CT and MRI included single node with maximum diameter ofor =4 mm, and the presence of central necrosis or ringed enhancement; the criteria for (18)FDG-PET-CT included abnormal accumulation of irradiation in the RLN with the standard uptake value (SUV) ofor =2.5. Considering the response of RLN to clinical treatment, the differences of CT, MRI, and PET-CT in detecting RLN metastasis were compared.Among the 106 intropharyngeal spaces of the 53 patients, the positive rate of RLN metastasis was significantly higher detected by CT and MRI than by PET-CT (39.6% and 45.3% vs. 20.8%, P0.01), but the difference between CT and MRI was not significant (P0.05). CT detected 27 cases of RLN metastasis with the maximum diameter of 0.4-0.9 cm, MRI detected 31 cases, and PET-CT only detected 5 cases. Especially, MRI detected 7 cases of RLN metastasis with the maximum diameter ofor =0.5 cm, CT detected 4 cases, but PET-CT detected none. CT detected 12 cases of RLN metastasis with the maximum diameter ofor =1.0 cm, MRI detected 14 cases, and PET-CT detected 13 cases. All patients were followed-up after treatment. One case of RLN metastasis with necrosis and the maximum diameter of 1.0 cm, and 1 case with the maximum diameter of 1.5 cm were eliminated within 6 months after treatment; the rest were eliminated within 3 months.In detecting RLN metastasis in NPC, MRI has no obvious advantage over CT, while PET-CT is markedly inferior to CT and MRI, especially in detecting the cases with the maximum diameter of1.0 cm. Furthermore, the metastatic RLNs with necrosis or the maximum diameter ofor =5 mm can't be detected by PET-CT. Setting the maximum diameter ofor =4 mm as a diagnosis criterion of RLN metastasis for CT or MRI is reasonable and feasible.

Purpose: To investigate the incidence, distribution, and spread pattern of retropharyngeal lymph node (RLN) involvement in patients with nasopharyngeal carcinoma (NPC) by using magnetic resonance imaging (MRI). Methods and Materials: The MR images of 275 patients with newly diagnosed NPC were reviewed retrospectively. Nodes were classified as metastatic based on size criteria, the presence of nodal necrosis, and extracapsular spread. Results: Retropharyngeal lymph node involvement was detected in 175 (63.6%) patients. Metastatic RLNs were seen at the following levels: occipital bone, 24 (9.6%) nodes; C1, 157 (62.5%) nodes; C1/2, 40 (15.9%) nodes; C2, 27 (10.8%) nodes; C2/3, 1 (0.4%) node; and C3, 2 (0.8%) nodes. The incidence of RLN involvement was equal to the incidence of cervical lymph node involvement (81.4% vs. 81.4%) in 215 patients with nodal metastases. A significantly higher incidence of metastatic RLNs was observed in the presence of oropharynx, prestyloid parapharyngeal space, post-styloid parapharyngeal space, longus colli muscle, medial pterygoid muscle, levator muscle of velum palatini, tensor muscle of velum palatini, Level II node, Level III node, and Level V node involvement. A significantly lower incidence of metastatic RLNs was found in T1, N0, and Stage I disease. Conversely, no significant difference in the incidence of metastatic RLNs was observed between T1, 2, and, 3; N2 and N3; or Stage II, III, and IV disease. Conclusions: There is an orderly decrease in the incidence of metastatic lateral RLNs from the C1 to C3 level. Metastatic RLNs associate well with involvement of certain structures in early stage primary tumors and lymph node metastases of the upper jugular chain (Level II, Level III nodes) and the posterior triangle (Level V nodes). Both RLNs and cervical Level II nodes appear to be the first-echelon nodes in NPC.