Imaging gastrointestinal damage due to acute mercury poisoning using a mitochondria-targeted dual near-infrared fluorescent probe.

Mercury (Hg) is one of the most widespread pollutants that pose serious threats to public health and the environment. People are inevitably exposed to Hg via different routes, such as respiration, dermal contact, drinking or diet. Hg poisoning could cause gingivitis, inflammation, vomiting and diarrhea, respiratory distress or even death. Especially during the developmental stage, there is considerable harm to the brain development of young children, causing serious symptoms such as intellectual disability and motor impairments, and delayed neural development. Therefore, it's of great significance to develop a specific, quick, practical and labor-saving assay for monitoring Hg2+. Herein, a mitochondria-targeted dual (excitation 700 nm and emission 728 nm) near-infrared (NIR) fluorescent probe JZ-1 was synthesized to detect Hg2+, which is a turn-on fluorescent probe designed based on the rhodamine fluorophore thiolactone, with advantages of swift response, great selectivity, and robust anti-interference capability. Cell fluorescence imaging results showed that JZ-1 could selectively target mitochondria in HeLa cells and monitor exogenous Hg2+. More importantly, JZ-1 has been successfully used to monitor gastrointestinal damage of acute mercury poisoning in a drug-induced mouse model, which provided a great method for sensing Hg species in living subjects, as well as for prenatal diagnosis.

Lista de verificación: tomografía computarizada de cuello en urgencias no traumáticas / Checklist: Neck computed tomography in non-traumatic emergencies

A los pacientes que acuden a urgencias con síntomas inflamatorio/infecciosos a nivel cervical o con masas que pueden comprometer el tracto aerodigestivo o las estructuras vasculares, es necesario hacerles una tomografía computarizada (TC) de cuello con contraste. Su interpretación radiológica se ve dificultada por la complejidad anatómica y la interrelación fisiopatológica entre los diferentes sistemas que lo componen, en un área de estudio relativamente pequeña. Estudios recientes proponen realizar una evaluación sistemática de las estructuras cervicales, utilizando para ello un listado de verificación de 7 elementos, para identificar correctamente la patología, y detectar los hallazgos incidentales que pueden interferir en el manejo del paciente. El objetivo de este trabajo es revisar los hallazgos de la TC en la patología no traumática del cuello en urgencias siguiendo una lectura sistemática, tras la cual se pueda realizar un informe radiológico estructurado, completo y conciso.(AU)

Patients attending the emergency department (ED) with cervical inflammatory/infectious symptoms or presenting masses that may involve the aerodigestive tract or vascular structures require a contrast-enhanced computed tomography (CT) scan of the neck. Its radiological interpretation is hampered by the anatomical complexity and pathophysiological interrelationship between the different component systems in a relatively small area. Recent studies propose a systematic evaluation of the cervical structures, using a 7-item checklist, to correctly identify the pathology and detect incidental findings that may interfere with patient management. As a conclusion, the aim of this paper is to review CT findings in non-traumatic pathology of the neck in the ED, highlighting the importance of a systematic approach in its interpretation and synthesis of a structured, complete, and concise radiological report.(AU)

Feasibility and clinical value of linear endoscopic ultrasonography imaging in the lower gastrointestinal subepithelial lesions.

Linear endoscopic ultrasonography (EUS) has been extensively utilized as a novel diagnostic and therapeutic modality across various fields. However, there have been relatively few studies focusing on lower gastrointestinal lesions. The aim of our study was to investigate the feasibility, safety and clinical value of linear EUS in the lower gastrointestinal subepithelial lesions. This was a retrospective study involving patients with lower gastrointestinal subepithelial lesions diagnosed by linear EUS from August 2019 to April 2023 at the Second Affiliated Hospital of Anhui Medical University. The data, including basic clinical information, linear EUS features, technical success rate, complications, and follow-up, were retrospectively collected and analyzed. A total of 69 patients with lower gastrointestinal subepithelial lesions underwent examination by linear EUS. Excluding the rectum, the technical success rate of linear EUS was 90.6% (29/32). Apart from the 7 patients whose diagnosis remained unknown, 3 patients with no abnormal EUS findings, and 3 patients failed the procedure, 56 patients were included in the final diagnostic performance analysis. The most common locations of the lesions were the rectum (37/56, 66.1%) and sigmoid colon (7/56, 12.5%). Based on endoscopy findings and pathological results, the most prevalent types of subepithelial lesions in the lower gastrointestinal tract were neuroendocrine tumor (NET) (12/56, 20.3%), lipoma (8/56, 13.6%) and extraluminal compression (8/56, 13.6%). The majority of lesions ranged in diameter from 1 to 3 cm (χ2 = 18.750, p < 0.001). After undergoing linear EUS examination, 36 patients received EUS-FNA (3/36), biopsy (5/36), endoscopic resection (25/36), or surgical excision (3/36) respectively. The pathological results of 29 patients were entirely consistent with the diagnosis made using linear EUS, with an 80.6% (29/36) diagnostic accuracy rate. Follow-up indicated that the lesions remained unchanged within 6-36 months. All patients tolerated the procedure well without any complications. In conclusion, linear EUS demonstrates technical feasibility, safety, and a high diagnostic accuracy for subepithelial lesions in the lower gastrointestinal tract.

[Emergency diagnoses in the gastrointestinal tract]. / Notfalldiagnosen im Gastrointestinaltrakt.

Gastrointestinal emergencies are a frequent reason for presentation in the emergency department and involve patients of all ages. The patients must undergo an immediate cross-sectional imaging as in many cases the underlying pathology is a life-threatening condition, which often needs surgical or in some cases also interventional radiological treatment. In this overview, the most important differential diagnoses and their characteristics on cross-sectional imaging are presented.

Autoimmune disorders of the gastrointestinal tract: Review of radiological appearances.

Autoimmune gastrointestinal (GI) disorders comprise a heterogeneous group of diseases with non-specific clinical manifestations. These are divided into primary and secondary. A high index of clinical suspicion complemented with endoscopic and radiological imaging may allow early diagnosis. Due to the relatively low incidence of autoimmune disorder, the imaging literature is sparse. In this review, we outline the pathogenesis, classification, and imaging appearances of autoimmune GI disorders.

Endoscopic Evaluation of PET/CT Abnormalities in the Gastrointestinal Tract: Yield and Approach.

BACKGROUND: Unexpected hypermetabolic activity is often encountered in the gastrointestinal tract when PET/CT is performed for various indications, prompting endoscopic evaluation. Our aim was to characterize the types of lesions seen in segments of the gastrointestinal tract with unexpected PET/CT abnormalities as well as clinically significant lesions seen on endoscopy which did not produce a PET/CT abnormality to guide the endoscopist tasked with evaluating these imaging findings. METHODS: We retrospectively reviewed a database of endoscopies performed at City of Hope Comprehensive Cancer Center between January 1, 2016 and September 30, 2021 for an indication of "abnormal PET." We divided the gastrointestinal tract into segments and defined categories of endoscopic/histologic findings for each segment. We counted the number of segments with an abnormal PET/CT finding and corresponding endoscopic/histologic abnormality as well as the number of segments with an endoscopic/histologic abnormality but normal PET/CT. RESULTS: PET/CT identified 209 segments with hypermetabolic activity, 109 of which had corresponding endoscopic/histologic abnormalities. In the jejunum and ileum, all corresponding lesions were malignant. Seventy-three percent of corresponding lesions in the stomach were H. pylori positive. PET/CT failed to detect 34.7% of clinically significant lesions diagnosed endoscopically, including 1 malignancy in the transverse colon and many inflammatory or low-risk premalignant lesions. CONCLUSION: PET/CT abnormalities seen in the small bowel should be evaluated urgently as nearly all correlates were malignant, while abnormalities in the stomach should prompt workup for H. pylori. Most lesions missed by PET/CT were inflammatory or low-risk premalignant yet clinically significant, confirming the need to inspect the entirety of the upper or lower gastrointestinal tract during endoscopy.

Acupuncture as a Therapeutic Intervention for Acute Gastrointestinal Injury (AGI): A Preliminary Study.

Acute gastrointestinal injury (AGI) is a significant factor contributing to increased mortality in patients receiving intensive care unit (ICU) care. Traditional Chinese medicine's acupuncture techniques offer an alternative approach to treating digestive disorders by controlling gastrointestinal secretion, improving gastrointestinal motility, and minimizing side effects. Transabdominal intestinal ultrasonography has proven effective in assessing gastrointestinal injury in critically ill patients. This study aims to evaluate the therapeutic effect of acupuncture in AGI patients using ultrasound. The main steps of the study include the syndrome-based selection of appropriate acupuncture points, including Hegu (LI4), Zhongwan (CV 12), Tianshu (ST 25), Zusanli (ST 36), Shangjuxu (ST 37), and Xiajuxu (ST 39), followed by a 30 min Deqi acupuncture session once a day for 1 week. The treatment's effectiveness is assessed by an experienced physician using abdominal gastrointestinal ultrasonography. This article provides a detailed account of how to standardize the use of acupuncture in treating gastrointestinal dysfunction in critically ill patients.

Utilidad de la endoscopia intraoperatoria en cirugía esofagogástrica / The utility of intraoperative endoscopy in esophagogastric surgery

La endoscopia flexible (EF) es un procedimiento de gran utilidad para el manejo diagnóstico y terapéutico de lesiones del tracto digestivo superior. A pesar de que su uso intraoperatorio se ha extendido con el paso de los años, su empleo por parte de cirujanos es aún limitado en nuestro medio. Las oportunidades de capacitación en EF varían ampliamente entre instituciones, especialidades y países. La endoscopia intraoperatoria (EIO) presenta ciertas peculiaridades que aumentan su complejidad respecto a la EF estándar. La realización de EIO repercute positivamente en los resultados quirúrgicos aportándoles seguridad y calidad así como disminución de las complicaciones asociadas a estas técnicas. Debido a sus innumerables ventajas, su uso intraoperatorio por parte de cirujanos es actualmente un proyecto vigente en muchos países y forma parte de un futuro próximo en otros, extendiéndose su uso dentro de la especialidad de cirugía general gracias a la creación de proyectos de formación mejor estructurados. En este manuscrito se realiza una revisión y puesta al día de las indicaciones y utilidades de la endoscopia digestiva alta intraoperatoria en la cirugía esofagogástrica. (AU)

Flexible endoscopy (FE) plays a major role in the diagnosis and treatment of gastrointestinal disease. Although its intraoperative use has spread over the years, its use by surgeons is still limited in our setting. EF training opportunities are different among many institutions, specialties, and countries. Intraoperative endoscopy (IOE) presents peculiarities that increase its complexity compared to standard EF. IOE has a positive impact on surgical results, due to increased safety and quality, as well as a reduction in the complications. Due to its innumerable advantages, its intraoperative use by surgeons is currently a current project in many countries and is part of the near future in others because of the creation of better structured training projects. This manuscript reviews and updates the indications and uses of intraoperative upper gastrointestinal endoscopy in esophagogastric surgery. (AU)

Fluorescence imaging around the abdomen allows evaluation of gastrointestinal retention of various forms of diet in mice.

OBJECTIVES: The aims of this study were to evaluate gastrointestinal (GI) retention of an ingested meal by fluorescence imaging and compare how retention is affected by differences in the physical characteristics of meals. METHODS: Mice were given an oral fluorescent indocyanine green (ICG) probe enclosed in a liposome. We evaluated the correlation between abdominal and GI fluorescence signals. ICG was administered to mice treated with atropine, and abdominal fluorescence was observed repeatedly. Mice were continuously given a regular chow or a liquid diet containing a low or high methoxyl (LM or HM)-pectin through a catheter placed in the stomach for 2 d, after which the mice were given ICG. In all studies, the mice's abdominal and GI fluorescence signals were observed with in vivo imaging equipment. RESULTS: The fluorescence intensities (FIs) of the abdomen and the excised GI tract correlated strongly. Attenuation of the abdominal FI was delayed in the atropine-treatment group compared with the non-treated group. The attenuation of abdominal FI 8 to 24 h after ICG administration was significantly weakened in the HM group compared with the regular chow and LM groups. CONCLUSIONS: Observing FI attenuation around the abdomen allows for the evaluation of GI tract retention of an ingested meal. Compared with a solid meal, a liquid meal stays longer in the digestive tract, whereas a liquid meal in which the viscosity increases in the stomach is retained like a solid meal.

PET assessment of acute gastrointestinal graft versus host disease.

Acute gastrointestinal graft versus host disease (GI-GVHD) is a common complication following allogeneic haematopoietic cell transplantation (HCT), and is characterised by severe morbidity, frequent treatment-refractoriness, and high mortality. Early, accurate identification of GI-GVHD could allow for therapeutic interventions to ameliorate its severity, improve response rates and survival; however, standard endoscopic biopsy is inadequately informative in terms of diagnostic sensitivity or outcome prediction. In an era where rapid technological and laboratory advances have dramatically expanded our understanding of GI-GVHD biology and potential therapeutic targets, there is substantial scope for novel investigations that can precisely guide GI-GVHD management. In particular, the combination of tissue-based biomarker assessment (plasma cytokines, faecal microbiome) and molecular imaging by positron emission tomography (PET) offers the potential for non-invasive, real-time in vivo assessment of donor:recipient immune activity within the GI tract for GI-GVHD prediction or diagnosis. In this article, we review the evidence regarding GI-GVHD diagnosis, and examine the potential roles and translational opportunities posed by these novel diagnostic tools, with a focus on the evolving role of PET.

A Transformable Mucoadhesive Microgel Network for Noninvasive Multimodal Imaging And Radioprotection of a Large Area of the Gastrointestinal Tract.

The lack of noninvasive imaging and modulation of a large area of the gastrointestinal (GI) tract constrain the diagnosis and treatment of many GI-related diseases. Recent advances use novel mucoadhesive materials to coat a part of the GI tract and then modulate its functions. High mucoadhesion is the key factor of the partial coating, but also the limitation for not spreading and covering the lower GI tract. Here, a bismuth-pectin organic-inorganic hybrid complex is screened and engineered into a transformable microgel network (Bi-GLUE) with high flowability and mucoadhesion, such that it can quickly transit through and coat a large area of the GI tract. In murine and porcine models, Bi-GLUE delivers contrast agents to achieve real-time, large-area GI-tract imaging under X-ray or magnetic resonance  modalities and to facilitate the non-invasive diagnosis of familial adenomatous polyposis. Moreover, Bi-GLUE, like an intracorporal radiation shield, decreases the radiotoxicity in a whole-abdomen irradiation rat model. This transformable microgel network offers a new direction that can modulate a large area of the GI tract and may have broad applications for GI-related conditions.

Contrast-Enhanced Multispectral Optoacoustic Tomography for Functional Assessment of the Gastrointestinal Tract.

Real-time imaging and functional assessment of the intestinal tract and its transit pose a significant challenge to conventional clinical diagnostic methods. Multispectral optoacoustic tomography (MSOT), a molecular-sensitive imaging technology, offers the potential to visualize endogenous and exogenous chromophores in deep tissue. Herein, a novel approach using the orally administered clinical-approved fluorescent dye indocyanine green (ICG) for bedside, non-ionizing evaluation of gastrointestinal passage is presented. The authors are able to show the detectability and stability of ICG in phantom experiments. Furthermore, ten healthy subjects underwent MSOT imaging at multiple time points over eight hours after ingestion of a standardized meal with and without ICG. ICG signals can be visualized and quantified in different intestinal segments, while its excretion is confirmed by fluorescent imaging of stool samples. These findings indicate that contrast-enhanced MSOT (CE-MSOT) provides a translatable real-time imaging approach for functional assessment of the gastrointestinal tract.

Oral administration of PET tracers: Current status.

The oral route is the most widely used and preferable way of drug administration. Several pharmacokinetic processes play a role in the distribution of administered drugs. Therefore, accurate quantification of absorption, distribution, metabolism, excretion, and characterisation of drug kinetics after oral administration is extremely important for developing new human drugs. In vivo methods, such as gamma-scintigraphy, magnetic resonance imaging (MRI), and positron emission tomography (PET), have been used to analyse gastrointestinal tract (GIT) absorption behaviour. This scoping review provides an overview of PET studies that used oral tracer administration. A systematic literature search was performed using PubMed, EMBASE, Scopus, Science Direct, and Web of Science databases. Extensive variation between these studies was seen concerning acquisition protocols, quantification methods, and pharmacokinetic outcome parameters. Studies in humans indicate that it takes 10 to 30 min for the tracer to be in the intestine and about 100 min to reach its maximum concentration in the brain. In rodent studies, different pharmacokinetic parameters for the brain, blood, and GIT were estimated, showing the potential of PET to measure the absorption and distribution of drugs and pharmaceuticals non-invasively. Finally, regarding radiation protection, oral administration has a higher absorbed dose in GIT and, consequently, a higher effective dose. However, with the recent introduction of Long Axial Field of View (LAFOV) PET scanners, it is possible to reduce the administered dose, making oral administration feasible for routine clinical studies.

Comparative study of convolutional neural network architectures for gastrointestinal lesions classification.

The gastrointestinal (GI) tract can be affected by different diseases or lesions such as esophagitis, ulcers, hemorrhoids, and polyps, among others. Some of them can be precursors of cancer such as polyps. Endoscopy is the standard procedure for the detection of these lesions. The main drawback of this procedure is that the diagnosis depends on the expertise of the doctor. This means that some important findings may be missed. In recent years, this problem has been addressed by deep learning (DL) techniques. Endoscopic studies use digital images. The most widely used DL technique for image processing is the convolutional neural network (CNN) due to its high accuracy for modeling complex phenomena. There are different CNNs that are characterized by their architecture. In this article, four architectures are compared: AlexNet, DenseNet-201, Inception-v3, and ResNet-101. To determine which architecture best classifies GI tract lesions, a set of metrics; accuracy, precision, sensitivity, specificity, F1-score, and area under the curve (AUC) were used. These architectures were trained and tested on the HyperKvasir dataset. From this dataset, a total of 6,792 images corresponding to 10 findings were used. A transfer learning approach and a data augmentation technique were applied. The best performing architecture was DenseNet-201, whose results were: 97.11% of accuracy, 96.3% sensitivity, 99.67% specificity, and 95% AUC.

Transformer-based multi-task learning for classification and segmentation of gastrointestinal tract endoscopic images.

Despite being widely utilized to help endoscopists identify gastrointestinal (GI) tract diseases using classification and segmentation, models based on convolutional neural network (CNN) have difficulties in distinguishing the similarities among some ambiguous types of lesions presented in endoscopic images, and in the training when lacking labeled datasets. Those will prevent CNN from further improving the accuracy of diagnosis. To address these challenges, we first proposed a Multi-task Network (TransMT-Net) capable of simultaneously learning two tasks (classification and segmentation), which has the transformer designed to learn global features and can combine the advantages of CNN in learning local features so that to achieve a more accurate prediction in identifying the lesion types and regions in GI tract endoscopic images. We further adopted the active learning in TransMT-Net to tackle the labeled image-hungry problem. A dataset was created from the CVC-ClinicDB dataset, Macau Kiang Wu Hospital, and Zhongshan Hospital to evaluate the model performance. Then, the experimental results show that our model not only achieved 96.94% accuracy in the classification task and 77.76% Dice Similarity Coefficient in the segmentation task but also outperformed those of other models on our test set. Meanwhile, active learning also produced positive results for the performance of our model with a small-scale initial training set, and even its performance with 30% of the initial training set was comparable to that of most comparable models with the full training set. Consequently, the proposed TransMT-Net has demonstrated its potential performance in GI tract endoscopic images and it through active learning can alleviate the shortage of labeled images.

BARIUM SULFATE GELATIN AS A NOVEL APPROACH TO FACILITATE GASTROINTESTINAL TRACT POSITIVE CONTRAST STUDIES IN A CAPTIVE HARBOR SEAL (PHOCA VITULINA) AND CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS) WITHOUT RESTRAINT.

Gastrointestinal tract contrast medium studies are a valuable diagnostic modality to evaluate gastrointestinal anatomy, motility, and pathology. Four positive contrast medium studies were performed twice on a harbor seal (Phoca vitulina) and once each on two California sea lions (Zalophus californianus) to evaluate for gastrointestinal abnormalities by using barium-impregnated gelatin. Because marine mammals in human care routinely receive plain gelatin as a component of their diet and as secondary reinforcement, feeding a barium gelatin mitigates the need for tube feeding or restraint. Operant conditioning was used to position the pinnipeds for voluntary radiographs. The barium gelatin permitted adequate evaluation of gastric emptying and intestinal transit times and good evaluation of the structure of the intestinal tract. Full evaluation of gastric anatomy was limited due to the gelatin blocks not conforming to the stomach in their solid form and the barium quickly exiting the stomach as barium gelatin blocks disintegrated and because orthogonal views could not always be acquired. Even with these limitations, barium gelatin resulted in diagnostically valuable contrast imaging in a stress-free patient setting with reduced risk of aspiration and eliminated the effects that anesthesia can have on gastric motility as well as other anesthesia-associated risks.

Clinical significance of incidental 18 FDG PET uptake in the gastrointestinal tract: a retrospective cohort study.

BACKGROUND: Incidental gastrointestinal tract (GIT) uptake is found in up to 6.3% of patients undergoing positron emission tomography (PET). This may be physiologic or pathologic and requires endoscopic assessment. AIM: To determine the diagnostic yield of endoscopy in this setting and characterise PET avidity as a predictor of clinically significant findings. METHODS: We retrospectively reviewed all consecutive patients undergoing upper endoscopy or colonoscopy for incidental 18 FDG PET positivity in the GIT. RESULTS: A total of 255 patients (62% male, median age 67 years) underwent colonoscopy or sigmoidoscopy for 276 separate areas of PET avidity in the colon. Malignancy was found in 44 cases (16%), and a significant polyp was found in an additional 103 cases (37%). Neoplastic change was found more often in the case of intense compared with non-intense PET avidity (odds ratio (OR) 3.40, 95% confidence interval (CI) 1.95-5.93, P < 0.001), and in focal compared with diffuse uptake (OR 5.97, 95% CI 2.9-12.2, P < 0.001). Upper GIT endoscopy was performed in 75 patients (46 male, median age 63 years) for 77 isolated areas with PET avidity. Malignancy was found in 16 cases (21%), and all were new primary lesions. Numerically, malignant findings were more common in intense (29.7%) than non-intense (12.5%) PET avidity (OR 2.96, 95%, CI 0.92-9.57, P = 0.069). CONCLUSIONS: Both focal and intense colonic 18 FDG uptake correlate strongly with a high-risk polyp or malignant lesion. Up to 21% of all gastroscopies performed for evaluation of incidental PET uptake diagnosed a new primary malignancy. These referrals need appropriate triaging and timely endoscopic assessment.

Noninvasive Gastrointestinal Tract Imaging Using BSA-Ag2Te Quantum Dots as a CT/NIR-II Fluorescence Dual-Modal Imaging Probe in Vivo.

The combination of high-resolution computed tomography (CT) and the real-time sensitive second near-infrared window (NIR-II) fluorescence bioimaging can provide complementary information for the diagnosis, progression and prognosis of gastrointestinal disorders. Ag2Te quantum dots (QDs) are a kind of promising CT/NIR-II fluorescence dual-modal imaging probe due to their high atomic number and narrow bandgap. However, conventional Ag2Te QDs synthesized by oil phase approaches often suffer from complicated steps, harsh reaction conditions, and toxic organic solvents. Herein, we report the synthesis of bovine serum albumin (BSA)-Ag2Te QDs using a biomineralization approach for CT/NIR-II fluorescence dual-modal imaging of the gastrointestinal tract. The BSA-Ag2Te QDs are fabricated in a facile one-pot approach under mild conditions and exhibit homogeneous size, favorable monodispersity, admirable aqueous solubility, excellent X-ray attenuation properties, and outstanding NIR-II fluorescence performance. In vivo imaging experiments show that BSA-Ag2Te QDs can be used in gastrointestinal tract CT/NIR-II dual-modal imaging with high spatiotemporal resolution and sensitivity. In addition, in an intestinal obstruction mouse model, accurate lesion positioning and imaging-guided obstruction relief surgery are successfully realized based on BSA-Ag2Te QDs. Besides, BSA-Ag2Te QDs have outstanding biocompatibility in vitro and in vivo. This study presents a high-performance and biosafe CT/NIR-II fluorescence dual-modal imaging probe for visualizing the gastrointestinal tract in vivo.

Radiopaque Nanorobots as Magnetically Navigable Contrast Agents for Localized In Vivo Imaging of the Gastrointestinal Tract.

Magnetic nanorobots offer wireless navigation capability in hard-to-reach areas of the human body for targeted therapy and diagnosis. Though in vivo imaging is required for guidance of the magnetic nanorobots toward the target areas, most of the imaging techniques are inadequate to reveal the potential locomotion routes. This work proposes the use of radiopaque magnetic nanorobots along with microcomputed tomography (microCT) for localized in vivo imaging applications. The nanorobots consist of a contrast agent, barium sulfate (BaSO4 ), magnetized by the decoration of magnetite (Fe3 O4 ) particles. The magnetic features lead to actuation under rotating magnetic fields and enable precise navigation in a microfluidic channel used to simulate confined spaces of the body. In this channel, the intrinsic radiopacity of the nanorobots also provides the possibility to reveal the internal structures by X-ray contrast. Furthermore, in vitro analysis indicates nontoxicity of the nanorobots. In vivo experiments demonstrate localization of the nanorobots in a specific part of the gastrointestinal (GI) tract upon the influence of the magnetic field, indicating the efficient control even in the presence of natural peristaltic movements. The nanorobots reported here highlight that smart nanorobotic contrast agents can improve the current imaging-based diagnosis techniques by providing untethered controllability in vivo.

Non-traumatic adult acute abdomen with high-attenuation lesions or materials in the gastrointestinal tract on unenhanced computed tomography.

Computed tomography (CT) is an imaging modality that provides otherwise unobtainable information in the diagnostic workup for acute abdomen. The patient's clinical history, physical examination, and laboratory findings are essential for a correct diagnosis; however, some diagnoses are difficult to establish. Although contrast-enhanced CT is the preferred diagnostic tool and provides invaluable information, using only post-contrast images can lead to misdiagnoses. Unenhanced CT images are more useful than post-contrast images for detecting high-attenuation lesions or materials because surrounding tissues also show high attenuation on post-contrast images. Unenhanced CT often provides key imaging findings for a correct diagnosis; hence, the purpose of this article is to describe CT findings in acute abdomen with high-attenuation lesions in the gastrointestinal tract.