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Simple Summary: Worldwide gastrointestinal (GI) malignancies account for about 25% of the global cancer incidence. For some malignancies, screening programs, such as routine colon cancer screenings, have largely aided in the early diagnosis of those at risk. However, even after diagnosis, many GI malignancies lack robust biomarkers to serve as definitive staging and prognostic tools to aid in clinical decision-making. Radiomics uses high-throughput data to extract various features from medical images with the potential to aid personalized precision medicine. Machine learning is a technique for analyzing and predicting by learning from sample data, finding patterns in it, and applying it to new data. We reviewed the fundamental concepts of radiomics such as imaging data acquisition, lesion segmentation, feature design, and interpretation specific to GI cancer studies and assessed the clinical applications of radiomics and machine learning in diagnosis, staging, evaluation of tumor prognosis, and treatment response. Gastrointestinal (GI) cancers, consisting of a wide spectrum of pathologies, have become a prominent health issue globally. Despite medical imaging playing a crucial role in the clinical workflow of cancers, standard evaluation of different imaging modalities may provide limited information. Accurate tumor detection, characterization, and monitoring remain a challenge. Progress in quantitative imaging analysis techniques resulted in "radiomics", a promising methodical tool that helps to personalize diagnosis and treatment optimization. Radiomics, a sub-field of computer vision analysis, is a bourgeoning area of interest, especially in this era of precision medicine. In the field of oncology, radiomics has been described as a tool to aid in the diagnosis, classification, and categorization of malignancies and to predict outcomes using various endpoints. In addition, machine learning is a technique for analyzing and predicting by learning from sample data, finding patterns in it, and applying it to new data. Machine learning has been increasingly applied in this field, where it is being studied in image diagnosis. This review assesses the current landscape of radiomics and methodological processes in GI cancers (including gastric, colorectal, liver, pancreatic, neuroendocrine, GI stromal, and rectal cancers). We explain in a stepwise fashion the process from data acquisition and curation to segmentation and feature extraction. Furthermore, the applications of radiomics for diagnosis, staging, assessment of tumor prognosis and treatment response according to different GI cancer types are explored. Finally, we discussed the existing challenges and limitations of radiomics in abdominal cancers and investigate future opportunities. [ABSTRACT FROM AUTHOR]

MR enterography (MRE) has become the primary imaging modality in the assessment of Crohn’s disease (CD) in both children and adults at many institutions in the United States and worldwide, primarily due to its noninvasiveness, superior soft tissue contrast, and lack of ionizing radiation. MRE technique includes distention of the small bowel with oral contrast media with the acquisition of T2-weighted, balanced steady-state free precession, and multiphase T1-weighted fat suppressed gadolinium contrast-enhanced sequences. With the introduction of molecule-targeted biologic agents into the clinical setting for CD and their potential to reverse the inflammatory process, MRE is increasingly utilized to evaluate disease activity and response to therapy as an imaging complement to clinical indices or optical endoscopy. New and emerging MRE techniques, such as diffusion-weighted imaging (DWI), magnetization transfer, ultrasmall superparamagnetic iron oxide- (USPIO-) enhanced MRI, and PET-MR, offer the potential for an expanded role of MRI in detecting occult disease activity, evaluating early treatment response/resistance, and differentiating inflammatory from fibrotic strictures. Familiarity with MR enterography is essential for radiologists and gastroenterologists as the technique evolves and is further incorporated into the clinical management of CD. [ABSTRACT FROM AUTHOR]

Aim: To describe our preliminary experience with simultaneous whole body (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography and magnetic resonance imaging (PET-MRI) in the evaluation of pediatric oncology patients., Methods: This prospective, observational, single-center study was Health Insurance Portability and Accountability Act-compliant, and institutional review board approved. To be eligible, a patient was required to: (1) have a known or suspected cancer diagnosis; (2) be under the care of a pediatric hematologist/oncologist; and (3) be scheduled for clinically indicated (18)F-FDG positron emission tomography-computed tomography (PET-CT) examination at our institution. Patients underwent PET-CT followed by PET-MRI on the same day. PET-CT examinations were performed using standard department protocols. PET-MRI studies were acquired with an integrated 3 Tesla PET-MRI scanner using whole body T1 Dixon, T2 HASTE, EPI diffusion-weighted imaging (DWI) and STIR sequences. No additional radiotracer was given for the PET-MRI examination. Both PET-CT and PET-MRI examinations were reviewed by consensus by two study personnel. Test performance characteristics of PET-MRI, for the detection of malignant lesions, including FDG maximum standardized uptake value (SUVmax) and minimum apparent diffusion coefficient (ADCmin), were calculated on a per lesion basis using PET-CT as a reference standard., Results: A total of 10 whole body PET-MRI exams were performed in 7 pediatric oncology patients. The mean patient age was 16.1 years (range 12-19 years) including 6 males and 1 female. A total of 20 malignant and 21 benign lesions were identified on PET-CT. PET-MRI SUVmax had excellent correlation with PET-CT SUVmax for both benign and malignant lesions (R = 0.93). PET-MRI SUVmax > 2.5 had 100% accuracy for discriminating benign from malignant lesions using PET-CT reference. Whole body DWI was also evaluated: the mean ADCmin of malignant lesions (780.2 + 326.6) was significantly lower than that of benign lesions (1246.2 + 417.3; P = 0.0003; Student's t test). A range of ADCmin thresholds for malignancy were evaluated, from 0.5-1.5 × 10(-3) mm(2)/s. The 1.0 × 10(-3) ADCmin threshold performed best compared with PET-CT reference (68.3% accuracy). However, the accuracy of PET-MRI SUVmax was significantly better than ADCmin for detecting malignant lesions compared with PET-CT reference (P < 0.0001; two-tailed McNemar's test)., Conclusion: These results suggest a clinical role for simultaneous whole body PET-MRI in evaluating pediatric cancer patients.

The purpose of this paper is to evaluate the role of imaging in inflammatory bowel disease (IBD), including detection of extraluminal complications and extraintestinal manifestations of IBD, assessment of disease activity and treatment response, and discrimination of inflammatory from fibrotic strictures. IBD is a chronic idiopathic disease affecting the gastrointestinal tract that is comprised of two separate, but related intestinal disorders; Crohn's disease and ulcerative colitis. The paper discusses, in detail the pros and cons of the different IBD imaging modalities that need to be considered in order to optimize the imaging and clinical evaluation of patients with IBD. Historically, IBD evaluation of the bowel has included imaging to assess the portions of the small bowel that are inaccessible to optical endoscopic visualization. This traditionally was performed using barium fluoroscopic techniques; however, cross-sectional imaging techniques (computed tomography and magnetic resonance imaging) are being increasingly utilized for IBD evaluation because they can simultaneously assess mural and extramural IBD manifestations. Recent advances in imaging technology, that continue to improve the ability of imaging to noninvasively follow disease activity and treatment response, are also discussed. This review article summarizes the current imaging approach in inflammatory bowel disease as well as the role of emerging imaging modalities.

Osteomyelitis is a significant cause of morbidity in children throughout the world. Multiple imaging modalities can be used to evaluate for suspected osteomyelitis, however magnetic resonance imaging (MRI) has distinct advantages over other modalities given its ability to detect early changes related to osteomyelitis, evaluate the true extent of disease, depict extraosseous spread of infection, and help guide surgical management. MRI has assumed a greater role in the evaluation of osteomyelitis with the increase in musculoskeletal infections caused by methicillin-resistant Staphylococcus aureus which have unique imaging features that are well-demonstrated with MRI. This review focuses primarily on the use of MRI in the evaluation of osteomyelitis in children and will include a discussion of the clinically important and characteristic findings on MRI of acute bacterial osteomyelitis and related conditions.

Selective cytokine inhibitory drugs (SelCIDs) are a novel class of phosphodiesterase 4 inhibitors discovered during a thalidomide analog discovery program. These analogs were evaluated for their ability to inhibit tumor angiogenesis, vascularity, and growth. Two analogs (CC-7034 and CC-9088) were identified that had enhanced antiangiogenic activity in Matrigel assays compared with parental thalidomide. These analogs also inhibited the growth of established K1735 and RENCA murine tumors. Tumors whose growth was suppressed by SelCID treatment exhibited decreased vessel density together with increased tumor cell hypoxia and death. The decrease in vascularity produced by SelCID treatment is attributed to a selective loss of vessels devoid of pericyte coverage, suggesting that these agents target immature tumor vessels. That tumor cell death was localized to relatively avascular or hypoxic areas, coupled with the fact that none of the analogs was cytotoxic in vitro against the tumor cells, demonstrates that these analogs are novel antivascular agents with potent antitumor activity.

The Ink4a/Arf locus is frequently methylated in colon carcinoma and other common human cancers, suggesting that the locus may play a broad, as yet poorly defined,role inhibiting tumor progression. We examined the influence of the locus in mice with multiple intestinal neoplasia (Min). Colon tumors in 3-month-old Min mice that were null for the Ink4a/Arf locus (-/-) were moderately larger than in Ink4a/Arf-wild-type (+/+) animals (P = 0.032). More strikingly, one-half of the -/- colon tumors were grossly red in color, whereas most of the +/+ tumors were white (P = 0.0025). This color difference remained statistically significant after normalizing for tumor area (P = 0.016). On histological analysis, -/- colon tumors displayed more RBCs near the tumor surface, twice the number of functional vessels, and features of carcinoma in situ not found in +/+ tumors. Biochemical analyses showed that red tumors had higher hemoglobin and vascular endothelial growth factor (VEGF) content than white tumors. Surprisingly, the small intestinal tumor burden was actually lower in -/- animals, and none of these tumors were red, underscoring the importance of tissue context in the function of the locus. These results provide direct evidence that the Ink4a/Arf locus inhibits colon tumor progression. The enhanced vascularity of the -/- tumors is particularly significant in light of the clinical importance of this property in the detection, recurrence, and therapy of colon tumors.

We examined the ability of recombinant murine interleukin-12 (rmIL-12) to inhibit the vasculature and growth of mammary carcinomas arising in situ in mouse mammary tumor virus (MMTV)-infected female C3H/HeN mice. Although it is a potent antiangiogenic and antitumor agent in many transplanted murine tumor models, rmIL-12 failed to inhibit the vascularity, reduce the perfusion, or alter the growth of these autochthonous carcinomas. Factors intrinsic to these tumor cells were unlikely to be responsible for therapy failure. This is because primary cells derived from these carcinomas responded to IFN-gamma, and rmIL-12 was effective against transplanted tumors arising from Mm5MT cells, a line established from a MMTV-induced mammary carcinoma in C3H mice. Factors intrinsic to the mice that host the autochthonous mammary carcinomas were also not responsible for failure, because they sponsored rmIL-12 antiangiogenic and antitumor effects against transplanted K1735 murine melanoma tumors. Instead, the autochthonous nature of the mammary carcinomas and their possession of a high percentage of mature, pericyte-covered vessels that are resistant to therapeutic regression may be responsible. This is supported by the observation that transplanted Mm5MT tumors had a lower proportion of pericyte-covered vessels and responded to rmIL-12 therapy. These results point to significant differences between the vasculature of transplanted and autochthonous murine tumors and indicate that their susceptibility to antivascular therapy may differ substantially.