Degree Of Contrast Enhancement Research Articles

Diagnostic Performance and Interreader Agreement of a Standardized MR Imaging Approach in the Prediction of Small Renal Mass Histology.

Purpose To assess the diagnostic performance and interreader agreement of a standardized diagnostic algorithm in determining the histologic type of small (≤4 cm) renal masses (SRMs) with multiparametric magnetic resonance (MR) imaging. Materials and Methods This single-center retrospective HIPAA-compliant institutional review board-approved study included 103 patients with 109 SRMs resected between December 2011 and July 2015. The requirement for informed consent was waived. Presurgical renal MR images were reviewed by seven radiologists with diverse experience. Eleven MR imaging features were assessed, and a standardized diagnostic algorithm was used to determine the most likely histologic diagnosis, which was compared with histopathology results after surgery. Interreader variability was tested with the Cohen κ statistic. Regression models using MR imaging features were used to predict the histopathologic diagnosis with 5% significance level. Results Clear cell renal cell carcinoma (RCC) and papillary RCC were diagnosed, with sensitivities of 85% (47 of 55) and 80% (20 of 25), respectively, and specificities of 76% (41 of 54) and 94% (79 of 84), respectively. Interreader agreement was moderate to substantial (clear cell RCC, κ = 0.58; papillary RCC, κ = 0.73). Signal intensity (SI) of the lesion on T2-weighted MR images and degree of contrast enhancement (CE) during the corticomedullary phase were independent predictors of clear cell RCC (SI odds ratio [OR]: 3.19; 95% confidence interval [CI]: 1.4, 7.1; P = .003; CE OR, 4.45; 95% CI: 1.8, 10.8; P < .001) and papillary RCC (CE OR, 0.053; 95% CI: 0.02, 0.2; P < .001), and both had substantial interreader agreement (SI, κ = 0.69; CE, κ = 0.71). Poorer performance was observed for chromophobe histology, oncocytomas, and minimal fat angiomyolipomas, (sensitivity range, 14%-67%; specificity range, 97%-99%), with fair to moderate interreader agreement (κ range = 0.23-0.43). Segmental enhancement inversion was an independent predictor of oncocytomas (OR, 16.21; 95% CI: 1.0, 275.4; P = .049), with moderate interreader agreement (κ = 0.49). Conclusion The proposed standardized MR imaging-based diagnostic algorithm had diagnostic accuracy of 81% (88 of 109) and 91% (99 of 109) in the diagnosis of clear cell RCC and papillary RCC, respectively, while achieving moderate to substantial interreader agreement among seven radiologists. © RSNA, 2018 Online supplemental material is available for this article.

Differences in Signal Intensity and Enhancement on MR Images of the Perivascular Spaces in the Basal Ganglia versus Those in White Matter

Purpose:To elucidate differences between the perivascular space (PVS) in the basal ganglia (BG) versus that found in white matter (WM) using heavily T2-weighted FLAIR (hT2-FL) in terms of 1) signal intensity on non-contrast enhanced images, and 2) the degree of contrast enhancement by intravenous single dose administration of gadolinium based contrast agent (IV-SD-GBCA).Materials and Methods:Eight healthy men and 13 patients with suspected endolymphatic hydrops were included. No subjects had renal insufficiency. All subjects received IV-SD-GBCA. MR cisternography (MRC) and hT2-FL images were obtained prior to and 4 h after IV-SD-GBCA. The signal intensity of the PVS in the BG, subinsular WM, and the cerebrospinal fluid (CSF) in Ambient cistern (CSFAC) and CSF in Sylvian fissure (CSFSyl) was measured as well as that of the thalamus. The signal intensity ratio (SIR) was calculated by dividing the intensity by that of the thalamus. We used 5% as a threshold to determine the significance of the statistical test.Results:In the pre-contrast scan, the SIR of the PVS in WM (Mean ± standard deviation, 1.83 ± 0.46) was significantly higher than that of the PVS in the BG (1.05 ± 0.154), CSFSyl (1.03 ± 0.15) and the CSFAC (0.97 ± 0.29). There was no significant difference between the SIR of the PVS in the BG compared to the CSFAC and CSFSyl. For the evaluation of the contrast enhancement effect, significant enhancement was observed in the PVS in the BG, the CSFAC and the CSFSyl compared to the pre-contrast scan. No significant contrast enhancement was observed in the PVS in WM.Conclusion:The signal intensity difference between the PVS in the BG versus WM on pre-contrast images suggests that the fluid composition might be different between these PVSs. The difference in the contrast enhancement between the PVSs in the BG versus WM suggests a difference in drainage function.

Global Contrast Enhancement Based Image Forensics Using Statistical Features

The evolution of modern cameras, mobile phones equipped with sophisticated image editing software has revolutionized digital imaging. In the process of image editing, contrast enhancement is a very common technique to hide visual traces of tampering. In our work, we have employed statistical distribution of block variance and AC DCT coefficients of an image to detect global contrast enhancement in an image. The variation in statistical parameters of block variance and AC DCT coefficients distribution for different degrees of contrast enhancement are used as features to detect contrast enhancement. An SVM classifier with 10-fold cross-validation is employed. An overall accuracy greater than 99% in detection with false rate less than 2% has been achieved. The proposed method is novel and it can be applied to uncompressed, previously JPEG compressed and post enhancement JPEG compressed images with high accuracy. The proposed method does not employ oft-repeated image histogram-based approach.

CT Angiography in the Emergency Department: Maximizing Contrast Enhancement and Image Quality While Minimizing Radiation Dose and Contrast Material Volume: Vascular/Interventional Radiology.

CT angiographic image quality and radiation dose can be optimized for each patient by applying knowledge of the principles of intravenous contrast material flow and the factors that influence contrast enhancement.

Role of Imaging in Response Assessment and Individualised Treatment for Sarcomas

The first systematic response evaluation criteria were established by WHO, based on the tumor size changes shortly after the computed tomography (CT) technique became available to the daily practice. RECIST, a simplified version of WHO criteria, and its newer version, RECIST1.1 are the currently available international response evaluation criteria in solid tumors and remains based on tumor size changes.While the introduction of molecularly targeted drugs has significantly improved the survival in patient with sarcomas, the evaluation of tumor response has become more complicated. Increasing number of studies have reported the lack of shrinkage in responding tumors and raised concerns of significant underestimation of responses using RECIST. The first such observation was made on gastrointestinal stromal tumor (GIST) treated with imatinib. In GISTs responding to imatinib, the degree of contrast enhancement on CT typically decreases significantly compared with the baseline, and, regardless of whether tumors shrink, heterogeneous hyperattenuating tumors become homogeneous hypoattenuating tumors with a smaller enhancing solid component.In current oncology practice, CT is a widely accepted method of evaluating tumor response. CT images are relatively simple to acquire and can be reasonably reproduced with no significant technical obstacles. FDG-PET is highly sensitive and specific in identifying responding sarcomas. It has mostly been used as a problem solver and for those with marginally resectable GIST. More recently, the utility of whole body MRI is undergoing exploration.This article discusses the traditional size-based response evaluation criteria, and introduces new evidence based response evaluation based on changes in morphology in addition to changes in tumor size on CT images, and whole body imaging is introduced at the end.

Pathology comparative study on the characteristic CT signs in solid pseudopapillary neoplasm of the pancreas.

In order to analyze characteristic CT signs in the solid pseudopapillary tumor of the pancreas, a retrospective analysis was conducted on 49 patients with pseudopapillary tumor of the pancreas who where treated in Liaoning Cancer Hospital. All of the patients were confirmed by pathology, CT signs were analyzed and a pathology contrast was conducted. Furthermore, all cases had single lesions; 7 cases in the pancreatic head, 23 cases in the pancreatic body, 15 cases in the pancreatic body-tail and 4 cases in the pancreatic tail. The boundaries of the lesions were clear and the tumors, which may outline the pancreas, were composed of solid and polycystic parts. In addition, calcifications could be observed in the lesions and CT results revealed varying degrees of contrast enhancement of the solid components in the arterial phase, as well as a gradual contrast enhancement in the venous and delayed phase. Enhancement of capsule could be observed, and the enhancement region was observed in the solid part, no enhancement in cystic part.. In conclusion, CT manifestations of solid pseudopapillary tumors of the pancreas are specific, which is helpful to the diagnosis.

Pseudoprogression, radionecrosis, inflammation or true tumor progression? challenges associated with glioblastoma response assessment in an evolving therapeutic landscape.

The wide variety of treatment options that exist for glioblastoma, including surgery, ionizing radiation, anti-neoplastic chemotherapies, anti-angiogenic therapies, and active or passive immunotherapies, all may alter aspects of vascular permeability within the tumor and/or normal parenchyma. These alterations manifest as changes in the degree of contrast enhancement or T2-weighted signal hyperintensity on standard anatomic MRI scans, posing a potential challenge for accurate radiographic response assessment for identifying anti-tumor effects. The current review highlights the challenges that remain in differentiating true disease progression from changes due to radiation therapy, including pseudoprogression and radionecrosis, as well as immune or inflammatory changes that may occur as either an undesired result of cytotoxic therapy or as a desired consequence of immunotherapies.

Local gray level S-curve transformation – A generalized contrast enhancement technique for medical images

Most medical images suffer from inadequate contrast and brightness, which leads to blurred or weak edges (low contrast) between adjacent tissues resulting in poor segmentation and errors in classification of tissues. Thus, contrast enhancement to improve visual information is extremely important in the development of computational approaches for obtaining quantitative measurements from medical images. In this research, a contrast enhancement algorithm that applies gray-level S-curve transformation technique locally in medical images obtained from various modalities is investigated. The S-curve transformation is an extended gray level transformation technique that results into a curve similar to a sigmoid function through a pixel to pixel transformation. This curve essentially increases the difference between minimum and maximum gray values and the image gradient, locally thereby, strengthening edges between adjacent tissues. The performance of the proposed technique is determined by measuring several parameters namely, edge content (improvement in image gradient), enhancement measure (degree of contrast enhancement), absolute mean brightness error (luminance distortion caused by the enhancement), and feature similarity index measure (preservation of the original image features). Based on medical image datasets comprising 1937 images from various modalities such as ultrasound, mammograms, fluorescent images, fundus, X-ray radiographs and MR images, it is found that the local gray-level S-curve transformation outperforms existing techniques in terms of improved contrast and brightness, resulting in clear and strong edges between adjacent tissues. The proposed technique can be used as a preprocessing tool for effective segmentation and classification of tissue structures in medical images.

Subjective and objective image differences in pediatric computed tomography cardiac angiography using lower iodine concentration.

Several recent studies showed the optimal contrast enhancement with a low-concentration and iso-osmolar contrast media in both adult and pediatric patients. However, low contrast media concentrations are not routinely used due to concerns of suboptimal enhancement of cardiac structures and small vessels. To evaluate the feasibility of using iso-osmolar contrast media containing a low iodine dose for CT cardiac angiography at 80kilovolts (kVp) in neonates and infants. The iodixanol 270 group consisted of 79 CT scans and the iopromide 370 group of 62 CT scans in patients ≤1year old. Objective measurement of the contrast enhancement was analyzed and contrast-to-noise ratios of the ascending aorta and left ventricle were calculated. Regarding subjective measurement, a four-point scale system was devised to evaluate degrees of contrast enhancement, image noise, motion artifact and overall image quality of each image set. Reader performance for correctly differentiating iodixanol 270 and iopromide 370 by visual assessment was evaluated. Group objective and subjective measurements were nonsignificantly different. Overall sensitivity, specificity and diagnostic accuracy for correctly differentiating iodixanol 270 and iopromide 370 by visual assessment were 42.8%, 59%, and 50%, respectively. The application of iodixanol 270 achieved optimal enhancement for performing pediatric cardiac CT angiography at 80kVp in neonates and infants. Objective measurements of contrast enhancement and subjective image quality assessments were not statistically different in the iodixanol 270 and iopromide 370 groups.

Abstract WP86: Early Detection of Aneurysm Growth by Volume and Surface Area Analysis Using 3D Modeling From CT Angiography

Introduction: Enlargement of unruptured aneurysms indicates an increased risk of rupture. Assessment of aneurysm growth is typically based on aneurysm max diameter. However, this method is often unreliable due to factors such as the degree of contrast enhancement, tilting among studies and artifacts. Hypothesis: Three-dimensional modeling can help to judge aneurysm growth. Methods: All aneurysm patients who underwent CTA (1.0-mm slice thickness) with at least one follow-up in 2015, were reviewed. Intracranial saccular aneurysms were selected and fusiform, dissecting and mycotic aneurysms were excluded. Growth was defined as more than a 0.5 mm increase in size compared with the first study. 3D models were created from the source data using 3D-slicer (http://www.slicer.org). Aneurysm extraction from the parent artery was performed semi-automatically and volume and surface area were calculated using vascular toolkit (http://www.vmtk.org). The Mann-Whitney test and ROC curve analysis were applied to compare cases which increased in size with no-change cases. Results: This research included 59 aneurysms in 51 patients that underwent 250 CTA, with follow-up duration of 50.0 ± 50.5 months. Nine aneurysms increased in size. In 5 of 9 cases, follow-up studies prior to growth detection were available. In these cases, maximum diameter change from the first study was not significant (P = 0.169). By contrast, volume and area were significantly different (P = 0.046 and 0.046, respectively). On ROC analysis, AUCs of maximum diameter, volume, and area changes were 0.7, 0.772 and 0.772. Conclusions: Calculating volume and area changes was useful to judge aneurysm growth earlier than size measurement.

Evaluation of the thrombus of abdominal aortic aneurysms using contrast enhanced ultrasound - preliminary results.

It is hypothesized that the degree of vascularization of the thrombus may have a significant impact on the rupture of aortic aneurysms. The presence of neovascularization of the vessel wall and mural thrombus has been confirmed only in histopathological studies. However, no non-invasive imaging technique of qualitative assessment of thrombus and neovascularization has been implemented so far. Contrast-enhanced ultrasound (CEUS) has been proposed as a feasible and minimally invasive technique for in vivo visualization of neovascularization in the evaluation of tumors and atherosclerotic plaques. The aim of this study was the evaluation of mural thrombus and AAAs wall with CEUS. CEUS was performed in a group of seventeen patients with AAAs. The mural thrombus enhancement was recognized in 12 cases, yet no significant correlation between the degree of contrast enhancement and AAAs diameter, thrombus width, and thrombus echogenicity was found. We observed a rise in AAAs thrombus heterogeneity with the increase in the aneurysm diameter (r = 0.62, p = 0.017). In conclusion CEUS can visualize small channels within AAAs thrombus, which could be a result of an ongoing angiogenesis. There is a need for further research to find out whether the degree of vascularization of the thrombus may have a significant impact on the rupture of aneurysms.

Temporal subtraction contrast-enhanced dedicated breast CT

The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described.An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE).The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0–16%), NCC (0–6%), NMI (0–13%) and TRE (0–34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was implemented using a parallel processing architecture resulting in rapid execution time for the iterative segmentation and intensity-adaptive registration techniques.Characterization of contrast-enhanced lesions is improved using temporal subtraction contrast-enhanced dedicated breast CT. Adaptation of Demons registration forces as a function of contrast-enhancement levels provided a means to accurately align breast tissue in pre- and post-contrast image acquisitions, improving subtraction results. Spatial subtraction of the aligned images yields useful diagnostic information with respect to enhanced lesion morphology and uptake.

Imaging features of intestinal-type and pancreaticobiliary-type invasive adenocarcinoma of the ampullary region

Objective To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) features of intestinal-type and pancreaticobiliary-type invasive adenocarcinomas of the ampullary region (IAARs) and investigate the value of the differential diagnosis. Methods The retrospective cross-sectional study was adopted. The clinicopathological data of 33 patients with IAAR who were admitted to the Lanzhou University Second Hospital (20 patients) and Affiliated Hospital of Ningbo University (13 patients) between September 2013 and August 2015 were collected. The patients underwent plain and enhanced scans of CT and MRI. (1) Observation indictors included tumor size, shape, growth pattern, boundary, internal structure, density and/or signal, style and/or degree of contrast enhancement, changes of bile and/or pancreatic duct, invasion and metastasis. (2) The clinical and imaging features of intestinal-type and pancreaticobiliary-type IAARs were compared. (3) Operation was performed after preoperative examinations, and patients received the postoperative pathological examination and immunohistochemistry. Measurement data with normal distribution were presented as ±s. Comparison between groups was evaluated with an independent sample t test, and count data were analyzed using the chi-square test. Results (1) Of 33 patients with IAAR, 19 received plain scan of CT, including 17 receiving simultaneous enhanced scan of CT. Fourteen patients [9 receiving diffussion-weighted imaging (DWI) sequence of MRI] received plain scan of MRI, including 12 receiving simultaneous enhanced scan of MRI. The maximum diameter of IAAR in 33 patients was (2.8±1.4)cm. Fourteen tumors were round-like or oval shape and 19 tumors were irregular shape. The intracavity type, extracavity type and mixed type of tumors were detected in 24, 6 and 3 patients, respectively. There were clear boundary of tumors in 17 patients and fuzzy boundary of tumors in 16 patients. Tumors of 5 patients had appeared necrotic and/or cystic, no hemorrhage or calcification was found in tumors of 33 patients. Density and signal of tumors were homogeneous in 18 patients and inhomogeneous in 15 patients. Of 29 patients receiving enhanced scan of CT or MRI, homogeneous enhancement and inhomogeneous enhancement were respectively detected in 14 and 15 patients, and mild enhancement, moderate enhancement and no enhancement were respectively detected in 15, 14 and 0 patients. Tumors of 9 patients in DWI showed slightly high or high signal. Thirty patients had secondary bile duct dilatation (3 with mild dilatation, 6 with moderate dilatation and 21 with severe dilatation), and 3 patients had no changes of bile duct. Twenty-six patients had secondary pancreatic duct dilatation and 7 had no changes of pancreatic duct. Sixteen patients had tumor invasion to pancreatic tissues and 7 had lymph node metastases. (2) Of 33 patients with IAAR, 19 had intestinal-type IAAR (8 males and 11 females) and 14 had pancreaticobiliary-type IAAR (11 males and 3 females). There was statistically significant difference in the gender between the 2 types of IAAR (χ2=4.388, P<0.05). The intracavity type, extracavity type and mixed type of tumors, clear boundary and fuzzy boundary of tumors, homogeneous and inhomogeneous density and/or signal of tumors, with and without tumor invasion to pancreatic tissues were respectively detected in 17, 0, 2, 13, 6, 14, 5, 6, 13 patients with intestinal-type IAAR and 7, 6, 1, 4, 10, 4, 10, 10, 4 patients with pancreaticobiliary-type IAAR, with statistically significant differences between the 2 types of IAAR (χ2=9.971, 5.125, 6.617, 5.125, P<0.05). (3) All the patients underwent surgery and received comprehensive diagnosis and tumor classification after pathological examination and immunohistochemistry. Conclusion There are certain characteristics of CT and MRI in intestinal-type and pancreaticobiliary-type IAARs, and gender, tumor growth pattern, boundary, density and/or signal, tumor invasion to pancreatic tissues have certain reference values for the differential diagnosis of intestinal- type and pancreaticobiliary-type IAARs. Key words: Ampullary neoplasms; Invasive adenocareinoma; Tomography, X-ray computed; Magne-tic resonance imaging

FEASIBILITY AND SAFETY OF CONTRAST-ENHANCED ULTRASOUND IN THE DISTAL LIMB OF SIX HORSES.

Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast-enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of six horses. For each horse, CEUS of the distal limb was performed after intravenous injections of 5 and 10 ml, as well as intra-arterial injections of 0.5 and 1 ml contrast medium. Vital parameters were monitored and CEUS images were assessed qualitatively and quantitatively for degree of contrast enhancement. None of the horses had clinically significant changes in their vital parameters after contrast medium injection. One horse had a transient increase in respiratory rate, and several horses had mild increases of systolic blood pressure of short duration after intravenous, but not after intra-arterial injections. Intra-arterial injection was possible in all horses and resulted in significantly improved contrast enhancement both quantitatively (P = 0.027) and qualitatively (P = 0.019). Findings from this study indicated that CEUS is a feasible and safe diagnostic test for evaluation of the equine distal limb. Future studies are needed to assess the clinical utility of this test for horses with musculoskeletal diseases.

Risk Factors for Femoral Head Deformity in the Early Stage of Legg-Calvé-Perthes Disease: MR Contrast Enhancement and Diffusion Indexes.

To determine whether changes in diffusion and/or contrast enhancement are of prognostic value in the early stage of Legg-Calvé-Perthes disease (LCPD). This study was approved by the institutional review board, and written informed consent was obtained from patient parents. Diffusion and contrast agent-enhanced magnetic resonance (MR) imaging studies were performed in 46 children (37 boys and nine girls; mean age, 7.5 years [age range, 3.3-11.9 years]) with unilateral LCPD at the early stage before development of extensive femoral head deformity. The degree of contrast enhancement was measured on the contrast-enhanced MR images, and the apparent diffusion coefficient (ADC) value was measured on the ADC map at various regions of interest in the proximal femur. The association of the MR imaging parameters that compared the affected side with the contralateral normal side with the femoral head deformity index value above 0.3 at 2 years was investigated. Increased diffusion in the metaphysis (P = .003) and decreased contrast enhancement in the central epiphysis (P = .034) were the significant prognostic indicators of subsequent femoral head deformation. ADC in the metaphysis 45% higher and a contrast enhancement in the central epiphysis 37% lower than those of the contralateral normal side are associated with a nonfavorable prognosis. For diffusion MR imaging, sensitivity was 83% (15 of 18), specificity was 86% (24 of 28), positive predictive value was 79% (15 of 19), negative predictive value was 89% (24 of 27), and accuracy was 85% (39 of 46). For contrast-enhanced MR imaging, sensitivity was 78% (14 of 18), specificity was 64% (18 of 28), positive predictive value was 58% (14 of 24), negative predictive value was 82% (18 of 22), and accuracy was 70% (32 of 46). Diffusion and contrast-enhanced MR imaging are potentially useful to assess risk of later development of femoral head deformity.

Magnetic resonance enterography in Crohn’s disease: new simple proposal to assess disease activity

PurposeThe aim is to determine the accuracy of magnetic resonance enterography (MRE) in evaluating Crohn’s disease (CD) activity. Materials and methodsSeventy-seven patients with CD underwent MRE. The primary analysis was to determine associations between MRE findings, Harvey–Bradshaw Index, and C-reactive protein (CRP), then we have created a new MRE score that it was also correlated with clinical and laboratory data. ResultsMRE score for CD significantly correlates with CRP (P=.003). Significant associations were found between degree of contrast enhancement and CRP (P=.002) and between comb sign and CRP (P=.001). ConclusionsThese results make MRE an important instrument for evaluation of CD activity.

Radiologic Characteristics of Surgically Resected Non-Small Cell Lung Cancer With ALK Rearrangement or EGFR Mutations

Radiogenomic features are predictive of anaplastic lymphoma kinase (ALK) rearrangement in surgically resected non-small cell lung cancer (NSCLC). ALK rearrangement was screened by fluorescent in situ hybridization in 497 patients with resected NSCLC. Of these, 198 patients screened for both ALK andepidermal growth factor receptor (EGFR) mutation were enrolled. Clinicopathologic findings, survival after surgical procedure, computed tomographic (CT) features, and maximum standardized uptake value according to different genotypes were investigated with univariate and multivariate analyses. A receiver operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors. The prevalence of ALK positivity in resected NSCLC was 5.0% (25 of 497). Patients with ALK rearrangement showed significant differences in terms of patient's age (p= 0.006 for ALK versus EGFR, and 0.04for ALK versus wild type [WT]/WT, respectively), solid lesion (p= 0.0074 for ALK versus EGFR), degree ofcontrast enhancement (p= 0.0006 for ALK versusEGFR), and lesion margin (p= 0.0011 for ALK versus EGFR, and 0.0314 for ALK versus WT/WT, respectively) compared with EGFR mutant and WT/WT cohorts. Multivariate analysis revealed that young age,solid lesion, lobulated margin, and hypoattenuation at contrast-enhanced CT scan were independent predictors of ALK positivity (p=0.027, 0.046, 0.001, 0.021, respectively). The area under the ROC curve of the predictive model was 0.832, which suggests good discrimination. ALK-rearranged lung cancer has characteristic clinical and imaging features compared with EGFR mutant or WT/WT cohorts. Our findings suggest that young age, lobulated margin, solid lesion, and hypoattenuation at contrast-enhanced CT scan are important predictors of ALK-rearranged lung cancer.

Superficial desmoid tumors: MRI and ultrasound imaging characteristics

ObjectivesTo describe the imaging characteristics of superficial desmoid tumors using magnetic resonance imaging (MRI) and high-resolution sonography (HRUS). MethodsWe retrospectively examined 18 patients (12 females and 6 males) with histologically proven superficial desmoids. Fourteen patients received MRI examinations, while 12 patients were examined with HRUS. The lesions were assessed with regard to location, muscular fascia involvement, and spread into the subcutaneous fatty tissue septa, adjacent muscle, and bone. In addition, size, shape, signal intensity/echogenicity relative to muscle, amount of collagen components, Doppler vascularity on HRUS and the degree of contrast enhancement in MRI were evaluated. ResultsAltogether there were 20 subcutaneous lesions: six involved the chest wall and the breasts, five the hip, four each the shoulder and the flank, and one the abdominal wall. All but three lesions showed a stellar-type configuration with multiple irregular sun-burst-like extensions along the fascial planes and septa of the subcutaneous fat tissue. The extensions spread away from the main tumor focus, and in nine lesions, these extensions reached the cutis. The remaining three lesions had a spindle shape and also presented extensions along the fascial planes. Another imaging feature in all lesions was the presence of variable amounts of collagen components, with typical low signal on MRI and/or fibrillar hyperechoic appearance in HRUS. ConclusionThe distinctive imaging features of collagen components associated with sun-burst-like extensions in our sample of superficial desmoids are valuable diagnostic clues in the challenging non-invasive differential diagnosis of these tumors.

Usefulness of Contrast Perfusion Echocardiography for Differential Diagnosis of Cardiac Masses

The aim of this study was to assess the usefulness of contrast perfusion echocardiography in the differential diagnosis of different types of cardiac masses. Conventional echocardiography and contrast perfusion echocardiography were performed in 72 patients with cardiac masses. The degree of contrast enhancement of the mass and an adjacent section of myocardium after injection of contrast agent was determined by visual inspection and quantitative time–signal intensity curve analysis. The difference in maximal steady-state pixel intensity between the mass and the adjacent myocardium (ΔAmass–myocardium) was calculated. All masses had a pathologic diagnosis or resolved after anticoagulation. All 16 cardiac masses without enhancement on visual inspection were confirmed to be cardiac thrombi. Twenty-four masses with incomplete enhancement on visual inspection were recognized as benign tumors with validation methods. Of the 32 cardiac masses with complete enhancement, 30 were confirmed as malignant tumors and two as benign tumors with validation methods. The sensitivity and specificity of ΔAmass–myocardium in differentiating thrombi from tumors were 93% and 100%, respectively, and 100% and 97% in differentiating malignant tumors from benign tumors and thrombi. Both visual and quantitative assessment of degree of enhancement of cardiac masses in relation to the adjacent myocardium during contrast perfusion echocardiography had high diagnostic accuracy for differentiation of a thrombus from a tumor or a benign tumor from a malignant tumor.

CT imaging spectrum and the histopathological features of adult metanephric adenoma.

To retrospectively evaluate the radiopathological features of adult metanephric adenoma (MA) and explore whether MA can be differentiated on CT images, including the basis of their morphological features and enhancement patterns. 18 consecutive MA cases (age range, 18-66 years; 9 males and 9 females) were pathologically proven and recruited in our study between January 2004 and June 2014. Unenhanced and contrast-enhanced CT were performed and correlated with corresponding pathological findings to differentiate between MA and other renal tumours. The enhancement pattern, lesion contour and presence of calcifications were evaluated. On unenhanced CT scan, the most common (n = 15, 83.3%) CT imaging characteristics were the presence of homogeneity and well-defined solid renal masses; the minority (n = 3, 16.7%) were heterogeneous or centrally located low-attenuation masses. Contrast-enhanced CT image revealed hypoattenuating heterogeneous masses with varying degrees of contrast enhancement in 16 (88.9%) cases, in contrast to those without increased attenuation in 2 (11.1%) cases. Scattered calcification was found only in one case (5.6%). Pathological results revealed that a total of 6 (33.3%) cases had concomitant malignant carcinoma components; 2 (11.1%) patients had malignant MA; and pure MA was found in 10 cases, with a surprisingly high proportion of malignant tumours. The positive-predictive values of "high" enhancement seemed relatively characteristic for the diagnosis of malignant and composite MA. Radiopathological features of adult MA and exploring whether MA can be differentiated on CT images, including the basis of their morphological features and enhancement patterns.