Magnetic resonance enterography in Crohn's disease: How we do it and common imaging findings

Crohn's disease(CD) is a chronic inflammatory disease of the gastrointestinal tract, with unpredictable clinical course by phases of relapses alternating with other of quiescence. The etiology is multifactorial and is still not completely known; globally the westernization of lifestyle is causing an increasing incidence of CD, with peak age of 20-30 years. The diagnostic workup begins with the evaluation of the clinical history, physical examination and laboratory tests. However, the clinical assessment is subjected interobserver variability and, occasionally, the symptoms of acute and chronic inflammation may be indistinguishable. In this regards, the role of magnetic resonance(MR) enterography is crucial to determine the extension, the disease activity and the presence of any complications without ionizing radiations, making this method very suitable for young population affected by CD. The purpose of this review article is to illustrate the MR enterography technique and the most relevant imaging findings of CD, allowing the detection of small bowel involvement and the assessment of disease activity.

Can the computed tomography texture analysis of colorectal liver metastases predict the response to first-line cytotoxic chemotherapy?

BACKGROUND Artificial intelligence in radiology has the potential to assist with the diagnosis,prognostication and therapeutic response prediction of various cancers.A few studies have reported that texture analysis can be helpful in predicting the response to chemotherapy for colorectal liver metastases,however,the results have varied.Necrotic metastases were not clearly excluded in these studies and in most studies the full range of texture analysis features were not evaluated.This study was designed to determine if the computed tomography(CT)texture analysis results of non-necrotic colorectal liver metastases differ from previous reports.A larger range of texture features were also evaluated to identify potential new biomarkers.AIM To identify potential new imaging biomarkers with CT texture analysis which can predict the response to first-line cytotoxic chemotherapy in non-necrotic colorectal liver metastases(CRLMs).METHODS Patients who presented with CRLMs from 2012 to 2020 were retrospectively selected on the institutional radiology information system of our private radiology practice.The inclusion criteria were non-necrotic CRLMs with a minimum size of 10 mm(diagnosed on archived 1.25 mm portal venous phase CT(FOLFOX,FOLFIRI,FOLFOXIRI,CAPE-OX,CAPE-IRI or capecitabine).The final study cohort consisted of 29 patients.The treatment response of the CRLMs was classified according to the RECIST 1.1 criteria.By means of CT texture analysis,various first and second order texture features were extracted from a single nonnecrotic target CRLM in each responding and non-responding patient.Associations between features and response to chemotherapy were assessed by logistic regression models.The prognostic accuracy of selected features was evaluated by using the area under the curve.RESULTS There were 15 responders(partial response)and 14 non-responders(7 stable and 7 with progressive disease).The responders presented with a higher number of CRLMs(P=0.05).In univariable analysis,eight texture features of the responding CRLMs were associated with treatment response,but due to strong correlations among some of the features,only two features,namely minimum histogram gradient intensity and long run low grey level emphasis,were included in the multiple analysis.The area under the receiver operating characteristic curve of the multiple model was 0.80(95%CI:0.64 to 0.96),with a sensitivity of 0.73(95%CI:0.48 to 0.89)and a specificity of 0.79(95%CI:0.52 to 0.92).CONCLUSION Eight first and second order texture features,but particularly minimum histogram gradient intensity and long run low grey level emphasis are significantly correlated with treatment response in non-necrotic CRLMs.

Digital liver biopsy:Bio-imaging of fatty liver for translational and clinical research

The rapidly growing field of functional, molecular and structural bio-imaging is providing an extraordinary new opportunity to overcome the limits of invasive liver biopsy and introduce a "digital biopsy" for in vivo study of liver pathophysiology. To foster the application of bio-imaging in clinical and translational research, there is a need to standardize the methods of both acquisition and the storage of the bio-images of the liver. It can be hoped that the combination of digital, liquid and histologic liver biopsies will provide an innovative synergistic tri-dimensional approach to identifying new aetiologies, diagnostic and prognostic biomarkers and therapeutic targets for the optimization of personalized therapy of liver diseases and liver cancer. A group of experts of different disciplines(Special Interest Group for Personalized Hepatology of the Italian Association for the Study of the Liver, Institute for Biostructures and Bio-imaging of the National Research Council and Bio-banking and Biomolecular Resources Research Infrastructure) discussed criteria, methods and guidelines for facilitating the requisite application of data collection. This manuscript provides a multi-Author review of the issue with special focus on fatty liver.

Abdominal and gastrointestinal manifestations in COVID-19 patients: Is imaging useful?

Coronavirus disease 2019(COVID-19)can be considered a systemic disease with a specific tropism for the vascular system,in which the alterations of the microcirculation have an important pathogenetic role.The lungs are the main organ involved in COVID-19,and severe progressive respiratory failure is the leading cause of death in the affected patients;however,many other organs can be involved with variable clinical manifestations.Concerning abdominal manifestations,the gastrointestinal tract and the hepatobiliary system are mainly affected,although the pancreas,urinary tract and spleen may also be involved.The most common gastrointestinal symptoms are loss of appetite,followed by nausea and vomiting,diarrhea and abdominal pain.Gastrointestinal imaging findings include bowel wall thickening,sometimes associated with hyperemia and mesenteric thickening,fluid-filled segments of the large bowel and rarely intestinal pneumatosis and ischemia.Hepatic involvement manifests as an increase in the enzymatic levels of alanine aminotransferase,aspartate aminotransferase,serum bilirubin andγ-glutamyl transferase with clinical manifestations in most cases mild and transient.The most frequent radiological features are hepatic steatosis,biliary sludge and gallstones.Edematous acute pancreatitis,kidney infarct and acute kidney injury from acute tubular necrosis have been described more rarely in COVID-19.Lastly,splenic involvement is characterized by splenomegaly and by the development of solitary or multifocal splenic infarcts with classic wedge shaped or even rounded morphology,with irregular or smooth profiles.In summary,the abdominal radiological findings of COVID-19 are nonspecific and with poor pathological correlation reported in the literature.Ultrasound and particularly computed tomography with multiphasic acquisition are the diagnostic methods mainly utilized in COVID-19 patients with abdominal clinical symptoms and signs.Although radiological signs are not specific of abdominal and gastrointestinal involvement,the diagnostic imaging modalities and in particular computed tomography are helpful for the clinician in the management,evaluation of the severity and evolution of the COVID-19 patients.

Computed tomography colonography for the practicing radiologist:A review of current recommendations on methodology and clinical indications

Colorectal cancer(CRC) represents one of the most relevant causes of morbidity and mortality in Western societies. CRC screening is actually based on faecal occult blood testing, and optical colonoscopy still remains the gold standard screening test for cancer detection. However, computed tomography colonography(CT colonography) constitutes a reliable, minimally-invasive method to rapidly and effectively evaluate the entire colon for clinically relevant lesions. Furthermore, even if the benefits of its employment in CRC mass screening have not fully established yet, CT colonography may represent a reasonable alternative screening test in patients who cannot undergo or refuse colonoscopy. Therefore, the purpose of our review is to illustrate the most updated recommendations on methodology and the current clinical indications of CT colonography, according to the data of the existing relevant literature.