Absence Of Enhancement Research Articles

Acellular Dermal Matrix: Imaging Features With Histopathology Correlation.

Acellular dermal matrix (ADM) is an immunologically inert graft, typically from cadaveric skin, often used in postmastectomy breast reconstruction. Created from decellularized dermal tissues that have been treated to remove DNA and antigenic donor cells (leaving extracellular matrix), ADM is often used as a structural scaffold or sling to reinforce and support the structure and position of a breast implant during postoperative integration in implant-based breast reconstruction; ADM can also be used to fill cosmetic defects. Advantages of ADM use include improved cosmesis and reduced capsular contracture rates. On US, ADM can be seen as a subtle band with variable echogenicity adjacent to the implant. When folded on itself or redundant, ADM may present as a palpable oval mass with indistinct or circumscribed margins and variable echogenicity. On mammography, ADM can be seen as a circumscribed oval equal density mass when redundant and folded on itself; a layered appearance may be evident on tomosynthesis. On MRI, presence and absence of enhancement have been documented. Imaging findings likely vary depending on the degree of host tissue remodeling and incorporation, and when biopsied, histopathologically, ADM may be difficult to distinguish from scarring. Successful imaging diagnosis of ADM is aided by clinical knowledge of the intraoperative use and configuration of ADM, which may help differentiate ADM from new or recurrent malignancy and avoid unnecessary biopsy.

Multiparametric Ultrasound for Focal Testicular Pathology: A Ten-Year Retrospective Review.

Conventional ultrasonography (US), including greyscale imaging and colour Doppler US (CDUS), is pivotal for diagnosing scrotal pathologies, but it has limited specificity. Historically, solid focal testicular abnormalities often led to radical orchidectomy. This retrospective study evaluated the utilisation of contrast-enhanced ultrasound (CEUS) and strain elastography (SE) in investigating intratesticular focal abnormalities. A total of 124 cases were analysed. This study underscored the superior diagnostic capabilities of CEUS in detecting vascular enhancement in all malignant cases, even those with undetectable vascularity by CDUS. It also highlighted the potential of CEUS in identifying distinctive vascular patterns in benign vascular tumours. Definitive confirmation of benignity could be obtained when the absence of enhancement was demonstrated on CEUS. While SE alone offered no distinctive advantage in differentiating between benign and malignant pathologies, we demonstrated that incorporating a combination of CEUS and SE into the evaluation of focal testicular abnormalities could improve diagnostic performance metrics over conventional CDUS. Our findings underscore the role of advanced ultrasound techniques in enhancing the evaluation of focal testicular abnormalities in clinical practice and could aid a shift towards testis-sparing management strategies.

Towards consistency in pediatric brain tumor measurements: Challenges, solutions, and the role of artificial intelligence-based segmentation.

MR imaging is central to the assessment of tumor burden and changes over time in neuro-oncology. Several response assessment guidelines have been set forth by the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working groups in different tumor histologies; however, the visual delineation of tumor components using MRIs is not always straightforward, and complexities not currently addressed by these criteria can introduce inter- and intra-observer variability in manual assessments. Differentiation of non-enhancing tumors from peritumoral edema, mild enhancement from absence of enhancement, and various cystic components can be challenging; particularly given a lack of sufficient and uniform imaging protocols in clinical practice. Automated tumor segmentation with artificial intelligence (AI) may be able to provide more objective delineations, but rely on accurate and consistent training data created manually (ground truth). Herein, this paper reviews existing challenges and potential solutions to identifying and defining subregions of pediatric brain tumors (PBTs) that are not explicitly addressed by current guidelines. The goal is to assert the importance of defining and adopting criteria for addressing these challenges, as it will be critical to achieving standardized tumor measurements and reproducible response assessment in PBTs, ultimately leading to more precise outcome metrics and accurate comparisons among clinical studies.

Assessing the malignancy of suspicious breast microcalcifications: the role of contrast enhanced mammography.

To assess the role of contrast-enhanced mammography (CEM) in predicting the malignancy of breast calcifications. We retrospectively evaluated patients with suspicious calcifications (BIRADS 4) who underwent CEM and stereotactic vacuum-assisted biopsy (VAB) at our institution. We assessed the sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of CEM in predicting malignancy of microcalcifications with a 95% confidence interval; we performed an overall analysis and a subgroup analysis stratified into group A-low risk (BIRADS 4a) and group B-medium/high risk (BIRADS 4b-4c). We then evaluated the correlation between enhancement and tumour proliferation index (Ki-67) for all malignant lesions. Data from 182 patients with 184 lesions were collected. Overall the SE of CEM in predicting the malignancy of microcalcifications was 0.70, SP was 0.85, the PPV was 0.82, the NPV was 0.76 and AUC was 0.78. SE in group A was 0.89, SP was 0.89, PPV was 0.57, NPV was 0.98 and AUC was 0.75. SE in group B was 0.68, SP was 0.80, PPV was 0.87, NPV was 0.57 and AUC was 0.75. Among malignant microcalcifications that showed enhancement (N = 52), 61.5% had Ki-67 ≥ 20% and 38.5% had low Ki-67 values. Among the lesions that did not show enhancement (N = 22), 90.9% had Ki-67 < 20% and 9.1% showed high Ki-67 values 20%. The absence of enhancement can be used as an indicative parameter for the absence of disease in cases of low-suspicious microcalcifications, but not in intermediate-high suspicious ones for which biopsy remains mandatory and can be used to distinguish indolent lesions from more aggressive neoplasms, with consequent reduction of overdiagnosis and overtreatment.

ADH-Enhancer: an attention-based deep hybrid framework for enhancer identification and strength prediction.

Enhancers play an important role in the process of gene expression regulation. In DNA sequence abundance or absence of enhancers and irregularities in the strength of enhancers affects gene expression process that leads to the initiation and propagation of diverse types of genetic diseases such as hemophilia, bladder cancer, diabetes and congenital disorders. Enhancer identification and strength prediction through experimental approaches is expensive, time-consuming and error-prone. To accelerate and expedite the research related to enhancers identification and strength prediction, around 19 computational frameworks have been proposed. These frameworks used machine and deep learning methods that take raw DNA sequences and predict enhancer's presence and strength. However, these frameworks still lack in performance and are not useful in real time analysis. This paper presents a novel deep learning framework that uses language modeling strategies for transforming DNA sequences into statistical feature space. It applies transfer learning by training a language model in an unsupervised fashion by predicting a group of nucleotides also known as k-mers based on the context of existing k-mers in a sequence. At the classification stage, it presents a novel classifier that reaps the benefits of two different architectures: convolutional neural network and attention mechanism. The proposed framework is evaluated over the enhancer identification benchmark dataset where it outperforms the existing best-performing framework by 5%, and 9% in terms of accuracy and MCC. Similarly, when evaluated over the enhancer strength prediction benchmark dataset, it outperforms the existing best-performing framework by 4%, and 7% in terms of accuracy and MCC.

Prediction of pathological complete response of breast cancer patients who received neoadjuvant chemotherapy with a nomogram based on clinicopathologic variables, ultrasound, and MRI.

To establish a nomogram for predicting the pathologic complete response (pCR) in breast cancer (BC) patients after NAC by applying magnetic resonance imaging (MRI) and ultrasound (US). A total of 607 LABC women who underwent NAC before surgery between January 2016 and June 2022 were retrospectively enrolled, and then were randomly divided into the training (n = 425) and test set (n = 182) with the ratio of 7:3. MRI and US variables were collected before and after NAC, as well as the clinicopathologic features. Univariate and multivariate logistic regression analyses were applied to confirm the potentially associated predictors of pCR. Finally, a nomogram was developed in the training set with its performance evaluated by the area under the receiver operating characteristics curve (ROC) and validated in the test set. Of the 607 patients, 108 (25.4%) achieved pCR. Hormone receptor negativity (odds ratio [OR], 0.3; P < .001), human epidermal growth factor receptor 2 positivity (OR, 2.7; P = .001), small tumour size at post-NAC US (OR, 1.0; P = .031), tumour size reduction ≥50% at MRI (OR, 9.8; P < .001), absence of enhancement in the tumour bed at post-NAC MRI (OR, 8.1; P = .003), and the increase of ADC value after NAC (OR, 0.3; P = .035) were all significantly associated with pCR. Incorporating the above variables, the nomogram showed a satisfactory performance with an AUC of 0.884. A nomogram including clinicopathologic variables and MRI and US characteristics shows preferable performance in predicting pCR. A nomogram incorporating MRI and US with clinicopathologic variables was developed to provide a brief and concise approach in predicting pCR to assist clinicians in making treatment decisions early.

Novel scoring system using contrast-enhanced mammography to differentiate benign and malignant architectural distortion

BackgroundIncidence of malignancy in architectural distortion (AD) is variable, and as a standard of care, all the architectural distortions are biopsied. It is important to identify benign and malignant characteristics of ADs on imaging to predict the probability of malignancies as well as to establish radiological–pathological concordance. The aim of our study was to analyse the utility of contrast-enhanced mammography (CEM) in primary AD, to describe and evaluate the accuracy of CEM parameters and derive a novel scoring system to differentiate benign and malignant AD.ResultsForty-six patients with 49 ADs were evaluated with a median age, 51 years (age range—34–72 years) and all were women. Of the 49 ADs, 65.3% (32/49) were benign, and 34.69% (17/49) were malignant. The CEM parameters which predicted malignancy were moderate or marked density, size > 0.95 cm, CT ratio > 1.31, mass morphology and washout kinetics. The absence of enhancement and enhancing AD with AD score of 0 had a 100% NPV for malignancy. Enhancing architectural distortion with a score of 3 or more had 100% PPV for malignancy. A score of 1 or 2 was indeterminate, and an individualised decision was recommended.ConclusionsIn primary AD, several CEM features have significantly predicted malignancy when the score is 3 and above. A biopsy may be avoided in non-enhancing AD and enhancing AD with a score of 0 due to high NPV.

Contrast-Enhanced Mammography for Women with Palpable Breast Abnormalities

To examine the role of contrast-enhanced mammography (CEM) in the work-up of palpable breast abnormalities. In this single-center combination prospective-retrospective study, women with palpable breast abnormalities underwent CEM evaluation prospectively, comprising the acquisition of low energy (LE) images and recombined images (RI) which depict enhancement, followed by targeted ultrasound (US). Two independent readers retrospectively reviewed the imaging and assigned BI-RADS assessment based on LE alone, LE plus US, RI with LE plus US (CEM plus US), and RI alone. Pathology results or 1-year follow-up imaging served as the reference standard. 237 women with 262 palpable abnormalities were included (mean age, 51 years). Of the 262 palpable abnormalities, 116/262 (44%) had no imaging correlate and 242/262 (92%) were benign. RI alone had better specificity compared toLE plus US (Reader 1, 94% versus 89% (p=0.009); Reader 2, 93% versus 88% (p=0.03)), better positive predictive value (Reader 1, 52% versus 42% (p=0.04); Reader 2, 53% versus 42% (p=0.04)), and better accuracy (Reader 1, 93% versus 89% (p=0.05); Reader 2, 93% versus 90% (p=0.06)). CEM plus US was not significantly different in performance metrics versus LE plus US. RI had better specificity compared toLE in combination with US. There was no difference in performance between CEM plus US and LE plus US, likely reflecting the weight US carries in radiologist decision-making. However, the results indicate that the absence of enhancement on RI in the setting of palpable lesions may help avoid benign biopsies.

NON-ENHANCING/MINIMALLY ENHANCING GLIOMAS: CAN WE IDENTIFY LOW GRADE GLIOMAS?

Abstract AIMS Gliomas are traditionally separated into low-grade (LGG) and high-grade (HGG). As LGG are slower growing and with pressures on operating capacity, there is an argument that surgery for these patients can wait. Pre- operatively, contrast enhancement on imaging is usually taken as the method of differentiating grade, with the belief that the absence of enhancement indicates LGG. We therefore assessed patients with minimal/non- enhancing tumours and compared factors at diagnosis with final histological outcome. METHOD We identified a cohort of patients over a 19-month period with a first presentation to the neurosurgical oncology clinic with minimal/patchy/scattered foci of enhancement (ME) or no areas of contrast enhancement (NE) on imaging, collecting factors at diagnosis and histological outcome using electronic patient records. RESULTS Of 60 patients identified, 53.3% were HGG, 35.0% LGG and 11.7% non-glioma. In NE tumours HGG and LGG rates were equal (43.3%), whereas in ME tumours HGG comprised 63.3% versus 26.7% LGG. HGG patients were older on average than LGG (median age 53 years versus 33 years) and more prevalent in males (62.95%) compared to females (45.45%). HGG formed the majority of patients presenting with seizure only (60%), neurological deterioration only (50%) or ≥2 symptoms (57.6%), whereas LGG was higher in presentations with headache only (66.7%) or none of the symptoms (66.7%). CONCLUSIONS It is not possible to differentiate between ‘high-grade’ and ‘low-grade’ gliomas based on imaging findings alone. Age is clearly a differentiating factor, but symptoms do not appear to be. We are working to develop methods to better differentiate these tumours pre-operatively.

Is the Level of Contrast Enhancement on Contrast-Enhanced Mammography (CEM) Associated with the Presence and Biological Aggressiveness of Breast Cancer?

There is limited information about whether the level of enhancement on contrast-enhanced mammography (CEM) can be used to predict malignancy. The purpose of this study was to correlate the level of enhancement with the presence of malignancy and breast cancer (BC) aggressiveness on CEM. This IRB-approved, cross-sectional, retrospective study included consecutive patients examined with CEM for unclear or suspicious findings on mammography or ultrasound. Excluded were examinations performed after biopsy or during neoadjuvant treatment for BC. Three breast radiologists who were blinded to patient data evaluated the images. The enhancement intensity was rated from 0 (no enhancement) to 3 (distinct enhancement). ROC analysis was performed. Sensitivity and negative likelihood ratio (LR-) were calculated after dichotomizing enhancement intensity as negative (0) versus positive (1-3). A total of 156 lesions (93 malignant, 63 benign) in 145 patients (mean age 59 ± 11.6 years) were included. The mean ROC curve was 0.827. Mean sensitivity was 95.4%. Mean LR- was 0.12%. Invasive cancer presented predominantly (61.8%) with distinct enhancement. A lack of enhancement was mainly observed for ductal carcinoma in situ. Stronger enhancement intensity was positively correlated with cancer aggressiveness, but the absence of enhancement should not be used to downgrade suspicious calcifications.

Evolution of Radiographic Changes of a Vascularized Pedicled Nasoseptal Flap after Endonasal Endoscopic Skull Base Surgery.

There is active research involving the radiographic appearance of the skull base following reconstruction. The purpose of this study was to describe the radiographic appearance of the vascularized pedicle nasoseptal flap after endoscopic skull base surgery across time. We performed chart and imaging review of all patients with intraoperative nasoseptal flap placement during endoscopic skull base surgery at a tertiary academic skull base surgery program between July 2018 and March 2021. All patients underwent immediate and delayed (>3 months) postoperative MR imaging. Primary outcome variables included flap and pedicle enhancement, flap thickness, and flap adherence to the skull base. Sixty-eight patients were included. Flap (P = .003) enhancement significantly increased with time. Mean nasoseptal flap thickness on immediate and delayed postoperative scans was 3.8 and 3.9 mm, respectively (P = .181). The nasoseptal flap adhered entirely to the skull base in 37 (54.4%) and 67 (98.5%) patients on immediate and delayed imaging, respectively (P < .001). Our findings demonstrate heterogeneity of the nasoseptal flap appearance after skull base reconstruction. While it is important for surgeons and radiologists to evaluate variations in flap appearance, the absence of enhancement and lack of adherence to the skull base on immediate postoperative imaging do not appear to predict reconstructive success and healing, with many flaps "self-adjusting" with time.

Safety, Efficacy and Distribution of Doxorubicin Loaded Radiopaque Beads in Chemoembolization in Intermediate Stage Hepatocellular Carcinoma (HCC) with Correlation with Local Response.

The primary objectives of this study were to evaluate safety, and efficacy of Transarterial Chemoembolization (TACE) using doxorubicin-loaded radiopaque microspheres (DC Bead LUMI™) for the treatment of early and intermediate stage Hepatocellular Carcinoma (HCC) not amenable for curative treatments. Distribution of the microspheres was correlated with results post embolization. This was a prospective, single arm, open label study. The primary outcome measures were distribution of the radiopaque microspheres as showed by computerized tomography (CT) and local response measured by modified Response Evaluation Criteria (mRECIST) after Magnetic Resonance Imaging (MRI). Secondary measures were Time to Progression (TTP) and Overall Survival (OS). Fifty patients were enrolled over 36months. Median age was 69.0years; mean sum of target lesions diameters was 78.6 ± 36.8mm. There were no Grade 4 or 5 adverse events (AEs). At 6months Complete Response (CR) (18%), Partial Response (PR) (62%), Objective Response OR (80%) and Stable Disease (SD) (20%) were recorded. Before embolization, Diffusion Weighted Imaging (DWI) showed high signal (restricted diffusion). Post procedure, patients with dense deposition (< 5mm distance of microsphere aggregations) showed 100% absence of enhancement and no restriction in 30.6%. Median TTP was 8.3months. TTP for patients with CR was 13.3months and 7.2 and 5.6 for PR and SD, respectively. At 6 and 36months, survival was 94% and 34%, respectively. DC Bead LUMI™ is well tolerated and effective in early and intermediate stage HCC with maximal necrosis obtained in dense deposition in the target.

An MRI-based Scoring System for Preoperative Prediction of Axillary Response to Neoadjuvant Chemotherapy in Node-Positive Breast Cancer: A Multicenter Retrospective Study

To develop and validate a simplified scoring system by integrating MRI and clinicopathologic features for preoperative prediction of axillary pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) in clinically node-positive breast cancer. A total of 389 patients from three hospitals were retrospectively analyzed. To identify independent predictors for axillary pCR, univariable and multivariable logistic regression analyses were performed on pre- and post-NAC MRI and clinicopathologic features. Then, a simplified scoring system was constructed based on regression coefficients of predictors in the multivariable model, and its predictive performance was assessed with the receiver operating characteristic curve and calibration curve. The added value of the scoring system for reducing false-negative rate (FNR) of the sentinel lymph node biopsy (SLNB) was also evaluated. The simplified scoring system including seven predictors: progesterone receptor-negative (Three points), HER2-positive (Two points), post-NAC clinical T0-1 stage (Two points), pre-NAC higher ADC value of breast tumor (One point), absence of perinodal infiltration at pre-NAC (One point) and post-NAC MRI (Two points), and absence of enhancement in the tumor bed at post-NAC MRI (Two points), showed good calibration and discrimination, with AUCs of 0.835, 0.828 and 0.798 in the training, internal and external validation cohorts, respectively. The axillary pCR rates were increased with the total points of the scoring system, and patients with a score of ≥11 points had a pCR rate of 86%-100%. In test cohorts for simulating clinical application, the diagnostic accuracy for axillary pCR was 80%-90% among four different radiologists. Compared to standalone SLNB, combining the scoring system with SLNB reduced the FNR from 14.5% to 4.8%. The clinicopathologic-image scoring system with good predictive performance for axillary pCR in clinically node-positive breast cancer, may guide axillary management after NAC and improve patient selection for de-escalating axillary surgery to reduce morbidity.

A Score to Predict the Malignancy of a Breast Lesion Based on Different Contrast Enhancement Patterns in Contrast-Enhanced Spectral Mammography.

Simple SummaryContrast-enhanced spectral mammography (CESM) represents a novel, reliable imaging adjunct for the early detection and management of breast lesions by coupling high sensitivity and specificity. Early diagnosis of breast tumors using this innovative diagnostic method could help in reducing the high number of unnecessary biopsies for breast lesions considered as suspicious by standard radiological examination (such as mammography, ultrasound, and magnetic resonance). Considering its relative recent introduction, there are still no standardized methods for assessing the diagnostic performance of CESM enhancement descriptors. Here, we aim to create a score that takes account four CESM enhancement descriptors able to efficiently predict the malignancy of a breast lesion prior to biopsy.Background: To create a predictive score of malignancy of a breast lesion based on the main contrast enhancement features ascertained by contrast-enhanced spectral mammography (CESM). Methods: In this single-centre prospective study, patients with suspicious breast lesions (BIRADS > 3) were enrolled between January 2013 and February 2022. All participants underwent CESM prior to breast biopsy, and eventually surgery. A radiologist with 20 years’ experience in breast imaging evaluated the presence or absence of enhancement and the following enhancement descriptors: intensity, pattern, margin, and ground glass. A score of 0 or 1 was given for each descriptor, depending on whether the enhancement characteristic was predictive of benignity or malignancy (both in situ and invasive). Then, an overall enhancement score ranging from 0 to 4 was obtained. The histological results were considered the gold standard in the evaluation of the relationship between enhancement patterns and malignancy. Results: A total of 321 women (median age: 51 years; range: 22–83) with 377 suspicious breast lesions were evaluated. Two hundred forty-nine lesions (66%) have malignant histological results (217 invasive and 32 in situ). Considering an overall enhancement score ≥ 2 as predictive of malignancy, we obtain an overall sensitivity of 92.4%; specificity of 89.8%; positive predictive value of 94.7%; and negative predictive value of 85.8%. Conclusions: Our proposed predictive score on the enhancement descriptors of CESM to predict the malignancy of a breast lesion shows excellent results and can help in early breast cancer diagnosis and in avoiding unnecessary biopsies.

Normal Enhancement within the Vestibular Aqueduct: An Anatomic Review with High-Resolution MRI.

The normal appearance of the vestibular aqueduct on postcontrast MR images has not been adequately described in the literature. This study set out to characterize the expected appearance of the vestibular aqueduct, with particular emphasis on the enhancement of the structure on both 3D FSE T1 and 3D-FLAIR sequences. All MR imaging examinations of the internal auditory canals performed between March 1, 2021, and May 20, 2021, were retrospectively reviewed. All studies included high-resolution (≤0.5-mm section thickness) pre- and postgadolinium 3D FSE T1 with fat-saturated and postgadolinium 3D-FLAIR sequences. Two neuroradiologists independently reviewed the MR images of the vestibular aqueduct for the presence or absence of enhancement on both T1 and FLAIR images and compared the relative intensity of enhancement between sequences. The presence or absence of an enlarged vestibular aqueduct was also noted. Ninety-five patients made up the patient cohort, of whom 5 did not have postcontrast FLAIR images available (50 women [55.6%]). On both sides, enhancement was significantly more commonly seen on postgadolinium FLAIR (76/180, 42.2%) than on T1 fat-saturated images (41/190, 21.6%) (P < .001). The intensity of enhancement was significantly greater on postgadolinium FLAIR images than on T1 fat-saturated images (38.9% versus 3.7%, respectively; P < .001). Enhancement within the vestibular aqueduct is an expected finding on MR imaging and is both more common and more intense on postgadolinium 3D-FLAIR than on T1 fat-saturated sequences. Such enhancement should not be confused with pathology on MR imaging unless other suspicious findings are present.

SWI as an Alternative to Contrast-Enhanced Imaging to Detect Acute MS Lesions.

Acute inflammatory activity of MS lesions is traditionally assessed through contrast-enhanced T1-weighted MR images. The aim of our study was to determine whether a qualitative evaluation of non-contrast-enhanced SWI of new T2-hyperintense lesions might help distinguish acute and chronic lesions and whether it could be considered a possible alternative to gadolinium-based contrast agents for this purpose. Serial MR imaging studies from 55 patients with MS were reviewed to identify 169 new T2-hyperintense lesions. Two blinded neuroradiologists determined their signal pattern on SWI, considering 5 categories (hypointense rings, marked hypointensity, mild hypointensity, iso-/hyperintensity, indeterminate). Two different blinded neuroradiologists evaluated the presence or absence of enhancement in postcontrast T1-weighted images of the lesions. The Fisher exact test was used to determine whether each category of signal intensity on SWI was associated with gadolinium enhancement. The presence of hypointense rings or marked hypointensity showed a strong association with the absence of gadolinium enhancement (P < .001), with a sensitivity of 93.0% and a specificity of 82.9%. The presence of mild hypointensity or isohyperintensity showed a strong association with the presence of gadolinium enhancement (P < .001), with a sensitivity of 68.3% and a specificity of 99.2%. A qualitative analysis of the signal pattern on SWI of new T2-hyperintense MS lesions allows determining the likelihood that the lesions will enhance after administration of a gadolinium contrast agent, with high specificity albeit with a moderate sensitivity. While it cannot substitute for the use of contrast agent, it can be useful in some clinical settings in which the contrast agent cannot be administered.

Can Contrast-Enhanced Spectral Mammography (CESM) Reduce Benign Breast Biopsy?

Objectives To evaluate the potential of contrast-enhanced spectral mammography (CESM) in reducing benign breast biopsy rate, thereby improving resource utilization. To explore its potential as a value-adding modality in the management of BI-RADS 4/5 lesions. Materials and Methods This was a prospective study conducted between July 2016 and September 2018. Patients with BI-RADS 4/5 lesions detected on conventional imaging (mammogram, digital breast tomosynthesis, and ultrasound) were enrolled for adjunct CESM. Histopathologic correlation was done for all lesions. Additional suspicious lesions detected on CESM were all identified on second-look ultrasound and subsequently biopsied. Images were evaluated independently by two radiologists trained in breast imaging using BI-RADS classification. Presence of enhancement on CESM, BI-RADS score, and histopathology of each lesion were analyzed and tested with the chi-square/fisher-exact test for statistical significance. Results The study included 105 lesions in 63 participants—1 man and 62 women, an average age of 53.7 ± 10.8 years. On CESM, 22 (20.9%) of the lesions did not show enhancement. All 22 lesions had been classified as BI-RADS 4A and were subsequently proven to be benign. Of the remaining 83 enhancing lesions, 54 (65.1%) were malignant and 29 (34.9%) were benign (p < 0.05). CESM detected 6 additional lesions which were not identified on initial conventional imaging. Four of these were proven malignant and were in a different quadrant than the primary lesion investigated. Conclusion There is evidence that the absence of enhancement in CESM strongly favors benignity. It may provide the reporting radiologist with greater confidence in imaging assessment, especially in BI-RADS 4A cases, where a proportion of them are in actuality BI-RADS 3. Greater accuracy of BI-RADS grading can reduce nearly half of benign biopsies and allow better resource allocation. CESM also increases the detection rate of potentially malignant lesions, thereby changing the treatment strategies.

Natural catalyst for luminol chemiluminescence: application to validate peroxide levels in commercial hair dyes.

Here, we report a hydrothermally treated green leaves (Moringa oleifera) extract exploited as an efficient and highly sensitive catalyst to catalyze the chemiluminescence (CL) reaction of luminol. In the absence of enhancer, this green and hydrothermally treated catalyst was found to significantly enhance the CL intensity ~3.5-fold compared with the traditionally used K3 Fe(CN)6 catalyst. The structure and surface morphology of the catalyst was elucidated using X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The synergistic effect of the catalyst in the CL reaction was systematically investigated in the presence of hydrogen peroxide using ultraviolet-visible and CL spectroscopy. Studies showed that the sensitivity of the catalyst could be amplified by adjusting several parameters such as pH of the medium and concentrations of the base and luminol. The sensitivity of the novel-type catalyst was examined through the validation of hydrogen peroxide levels in commercial hair dye samples. Markedly, the catalyst displayed ultrasensitivity to hydrogen peroxide as the limit of detection of hydrogen peroxide using this catalyst was determined to be 0.02 μM under optimized conditions. In general, the proposed inexpensive, ecofriendly, and nontoxic catalyst could enable the determination of hydrogen peroxide for diverse analytical applications.

Endoscopic suspect of subacute occlusive mesenteric ischaemia

A 74-year-old patient presented to our emergency department with melena for 24 hours, associated with postprandial abdominal pain, predominantly in the epigastrium, for one month. Urgent gastroscopy showed a pale mucosa with loss of vascular pattern in the gastric antrum, as well as several superficial ulcers, Forrest III, at that level and in the duodenal bulb highly suggestive of ischaemia. An abdominal computed tomography angiography (CTA) revealed a filiform celiac trunk, with calcified atherosclerotic plaques in the ostium, superior mesenteric artery and both renal arteries, with absence of enhancement in a large part of the intestinal wall, suggestive of ischaemia. An exploratory laparoscopy confirmed patchy ischaemia of the small intestine, as well as of the cecum, ascending colon, and portion of the transversus. Atherosclerosis is the most common cause of occlusive chronic mesenteric ischaemia. The 'classic triad' consisting of postprandial pain, weight loss and abdominal bruit, is found in only a minority of patients, with a significant percentage of paucisymptomatic patients due to abundant colateral circulation, making diagnosis difficult. The endoscopic finding of edema, erythema or signs of mucosal atrophy, as well as gastric or duodenal ulcers, not justified by other causes can guide us in the diagnosis. However, more distal sections of the digestive tract which are not accessible with the conventional endoscope can often be affected, and the absence of these findings, does not exclude the diagnosis. Abdominal CTA is the gold-standard imaging test. Early diagnosis of mesenteric ischaemia is a challenge in clinical practice. Recognizing its endoscopic signs can facilitate its early diagnosis and treatment.

Whole set of constitutive promoters for RpoN sigma factor and the regulatory role of its enhancer protein NtrC in Escherichia coli K-12.

The promoter selectivity of Escherichia coli RNA polymerase (RNAP) is determined by its promoter-recognition sigma subunit. The model prokaryote E. coli K-12 contains seven species of the sigma subunit, each recognizing a specific set of promoters. Using genomic SELEX (gSELEX) screening in vitro, we identified the whole set of ‘constitutive’ promoters recognized by the reconstituted RNAP holoenzyme alone, containing RpoD (σ70), RpoS (σ38), RpoH (σ32), RpoF (σ28) or RpoE (σ24), in the absence of other supporting regulatory factors. In contrast, RpoN sigma (σ54), involved in expression of nitrogen-related genes and also other cellular functions, requires an enhancer (or activator) protein, such as NtrC, for transcription initiation. In this study, a series of gSELEX screenings were performed to search for promoters recognized by the RpoN RNAP holoenzyme in the presence and absence of the major nitrogen response enhancer NtrC, the best-characterized enhancer. Based on the RpoN holoenzyme-binding sites, a total of 44 to 61 putative promoters were identified, which were recognized by the RpoN holoenzyme alone. In the presence of the enhancer NtrC, the recognition target increased to 61–81 promoters. Consensus sequences of promoters recognized by RpoN holoenzyme in the absence and presence of NtrC were determined. The promoter activity of a set of NtrC-dependent and -independent RpoN promoters was verified in vivo under nitrogen starvation, in the presence and absence of RpoN and/or NtrC. The promoter activity of some RpoN-recognized promoters increased in the absence of RpoN or NtrC, supporting the concept that the promoter-bound NtrC-enhanced RpoN holoenzyme functions as a repressor against RpoD holoenzyme. Based on our findings, we propose a model in which the RpoN holoenzyme fulfils the dual role of repressor and transcriptase for the same set of genes. We also propose that the promoter recognized by RpoN holoenzyme in the absence of enhancers is the ‘repressive’ promoter. The presence of high-level RpoN sigma in growing E. coli K-12 in rich medium may be related to the repression role of a set of genes needed for the utilization of ammonia as a nitrogen source in poor media. The list of newly identified regulatory targets of RpoN provides insight into E. coli survival under nitrogen-depleted conditions in nature.