Diffusion-weighted imaging for evaluating inflammatory activity in Crohn's disease: comparison with histopathology, conventional MRI activity scores, and faecal calprotectin

PURPOSE: To evaluate whether the extent of enteric diffusion-weighted imaging (DWI) signal abnormality reflects inflammatory burden in Crohn's disease (CD), and to compare qualitative and quantitative grading. METHODS: 69 CD patients (35 male, age 16-78) undergoing MR enterography with DWI (MRE-D) and the same-day faecal calprotectin (cohort 1) were supplemented by 29 patients (19 male, age 16-70) undergoing MRE-D and terminal ileal biopsy (cohort 2). Global (cohort 1) and terminal ileal (cohort 2) DWI signal was graded (0 to 3) by 2 radiologists and segmental apparent diffusion coefficient (ADC) calculated. Data were compared to calprotectin and a validated MRI activity score [MEGS] (cohort 1), and a histopathological activity score (eAIS) (cohort 2) using nonparametric testing and rank correlation. RESULTS: Patients with normal (grades 0 and 1) DWI signal had lower calprotectin and MEGS than those with abnormal signal (grades 2 and 3) (160 vs. 492 μg/l, p = 0.0004, and 3.3 vs. 21, p  120 μg/l) were 83% and 52%, respectively. There was a negative correlation between ileal MEGS and ADC (r = -0.41, p = 0.017). There was no significant difference in eAIS between qualitative DWI scores (p = 0.42). Mean ADC was not different in those with and without histological inflammation (2077 vs. 1622 × 10(-6)mm(2)/s, p = 0.10) CONCLUSIONS: Qualitative grading of DWI signal has utility in defining the burden of CD activity. Quantitative ADC measurements have poor discriminatory ability for segmental disease activity

Repeatability of magnetic resonance measurements used for estimating Crohn's disease activity

Publisher Copyright: © 2020 Sciendo. All rights reserved. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.The MR activity indices used for quantification and follow-up of Crohn's disease are composed of a number of subjectively determinable components with equivocal repeatability. The purpose of this article was to assess the repeatability of measurements used for quantitative estimation of Crohn's disease activity in the terminal ileum. In five adults (23-57 y.o.) and 12 children (10-17 y.o.) with active terminal ileitis, the inflamed bowel was divided into 3 cm segments (n = 32 in adults, n = 46 in children), and measurements for the calculation of MaRIA and Clermont scores were performed. Parameters included apparent diffusion coefficients (ADC) for diffusion-weighted imaging (DWI) sequences with selective and non-selective fat suppression, wall signal enhancement before (WSI-preGd) and after (WSI-preGd) gadolinium enhancement, bowel thickness, and presence of ulcers. The measurements were standardised (accurate site-to-site comparison, exact ROI size, where applicable) and repeated by the same researcher after two months. Intra-observer agreement for ADC, WSI-preGd and WSI-postGd, bowel thickness was assessed with a paired t-test, and the significant difference in presence/absence of ulcers was assessed by the Pearson 2 test. Absolute difference was not found between the 1st and 2nd measurements of ADC, WSI-preGd, WSI-postGd and wall thickness. There was systematic difference in the presence of bowel ulcers. In standardised conditions the repeatability of ADC, WSI-preGd and WSI-postGd is high. Efforts must be made to precisely define the size and appearance of ulcers that may be included in the index calculation.publishersversionPeer reviewe

The Influence of Bowel Preparation on ADC Measurements: Comparison between Conventional DWI and DWIBS Sequences

Background and objectives: The aim of the study was to assess whether there were di ff erences between apparent di ff usion coe ffi cient (ADC) values of di ff usion-weighted imaging (DWI) and di ff usion-weighted imaging with background body signal suppression (DWIBS) sequences in non-prepared and prepared bowels before and after preparation with an enteric hyperosmolar agent, to assess whether ADC measurements have the potential to avoid bowel preparation and whether ADC-DWIBS has advantages over ADC-DWI. Materials and Methods: 106 adult patients without evidence of inflammatory bowel disease (IBD) underwent magnetic resonance (MR) enterography before and after bowel preparation. ADC-DWI and ADC-DWIBS values were measured in the intestinal and colonic walls demonstrating high signal intensity (SI) at DWI tracking images of b = 800 s /mm2 before and after preparation. Results: There were significant di ff erence (p < 0.0001) in both ADC-DWI and ADC-DWIBS results between non-prepared and prepared jejunum for DWI being 1.09 x 10 3 mm2 /s and 1.76 x 10 3 mm2 /s, respectively, and for DWIBS being 0.91 x 10 3 mm2 /s and 1.75 x 10 3 mm2 /s, respectively. Both ADC-DWI and DWIBS also showed significant di ff erence between non-prepared and prepared colon (p < 0.0001), with DWI values 1.41 x 10 3 mm2 /s and 2.13 x 10 3 mm2 /s, and DWIBS-1.01 x 10 3mm2 /s and 2.04 x 10 3mm2 /s, respectively. Nosignificant di ff erence between ADC-DWI and ADC-DWIBS was found in prepared jejunum (p = 0.84) and prepared colon (p = 0.58), whereas a significant di ff erence was found in non-prepared jejunum and non-prepared colon (p = 0.0001 in both samples). Conclusions: ADC between DWI and DWIBS does not di ff er in prepared bowel walls but demonstrates a di ff erence in non-prepared bowel. ADC in non-prepared bowel is lower than in prepared bowel and possible overlap with the ADC range of IBD is possible in non-prepared bowel. ADC-DWIBS has no advantage over ADC-DWI in regard to IBD assessment.publishersversionPeer reviewe

Crohn's Disease Imaging: A Review

Crohn's disease is a chronic granulomatous inflammatory disease of the gastrointestinal tract, which can involve almost any segment from the mouth to the anus. Typically, Crohn's lesions attain segmental and asynchronous distribution with varying levels of seriousness, although the sites most frequently involved are the terminal ileum and the proximal colon. A single gold standard for the diagnosis of CD is not available and the diagnosis of CD is confirmed by clinical evaluation and a combination of endoscopic, histological, radiological, and/or biochemical investigations. In recent years, many studies have been performed to investigate the diagnostic potential of less invasive and more patient-friendly imaging modalities in the evaluation of Crohn's disease including conventional enteroclysis, ultrasonography, color-power Doppler, contrast-enhanced ultrasonography, multidetector CT enteroclysis, MRI enteroclysis, and 99mTc-HMPAO-labeled leukocyte scintigraphy. The potential diagnostic role of each imaging modality has to be considered in different clinical degrees of the disease, because there is no single imaging technique that allows a correct diagnosis and may be performed with similar results in every institution. The aim of this paper is to point out the advantages and limitations of the various imaging techniques in patients with suspected or proven Crohn's disease

Biomechanical Computed Tomography analysis (BCT) for clinical assessment of osteoporosis.

The surgeon general of the USA defines osteoporosis as "a skeletal disorder characterized by compromised bone strength, predisposing to an increased risk of fracture." Measuring bone strength, Biomechanical Computed Tomography analysis (BCT), namely, finite element analysis of a patient's clinical-resolution computed tomography (CT) scan, is now available in the USA as a Medicare screening benefit for osteoporosis diagnostic testing. Helping to address under-diagnosis of osteoporosis, BCT can be applied "opportunistically" to most existing CT scans that include the spine or hip regions and were previously obtained for an unrelated medical indication. For the BCT test, no modifications are required to standard clinical CT imaging protocols. The analysis provides measurements of bone strength as well as a dual-energy X-ray absorptiometry (DXA)-equivalent bone mineral density (BMD) T-score at the hip and a volumetric BMD of trabecular bone at the spine. Based on both the bone strength and BMD measurements, a physician can identify osteoporosis and assess fracture risk (high, increased, not increased), without needing confirmation by DXA. To help introduce BCT to clinicians and health care professionals, we describe in this review the currently available clinical implementation of the test (VirtuOst), its application for managing patients, and the underlying supporting evidence; we also discuss its main limitations and how its results can be interpreted clinically. Together, this body of evidence supports BCT as an accurate and convenient diagnostic test for osteoporosis in both sexes, particularly when used opportunistically for patients already with CT. Biomechanical Computed Tomography analysis (BCT) uses a patient's CT scan to measure both bone strength and bone mineral density at the hip or spine. Performing at least as well as DXA for both diagnosing osteoporosis and assessing fracture risk, BCT is particularly well-suited to "opportunistic" use for the patient without a recent DXA who is undergoing or has previously undergone CT testing (including hip or spine regions) for an unrelated medical condition

Magnetic Resonance Enterography and Histology in Patients With Fibrostenotic Crohn's Disease: A Multicenter Study

INTRODUCTION Magnetic resonance enterography (MRE) is useful for detecting bowel strictures, whereas a number of imaging biomarkers may reflect severity of fibrosis burden in Crohn's disease (CD). This study aimed to verify the association of MRE metrics with histologic fibrosis independent of inflammation. METHODS This prospective European multicenter study performed MRE imaging on 60 patients with CD with bowel strictures before surgical resection. Locations of 61 histological samples were annotated on MRE examinations, followed by central readings using the Chiorean score and measurement of delayed gain of enhancement (DGE), magnetization transfer ratio, T2-weighted MRI sequences (T2R), apparent diffusion coefficient (ADC), and the magnetic resonance index of activity (MaRIA). Correlations of histology and MRE metrics were assessed. Least Absolute Shrinkage and Selection Operator and receiver operator characteristic (ROC) curve analyses were used to select composite MRE scores predictive of histology and to estimate their predictive value. RESULTS ADC and MaRIA correlated with fibrosis (R = -0.71, P < 0.0001, and 0.59, P < 0.001) and more moderately with inflammation (R = -0.35, P < 0.01, and R = 0.53, P < 0.001). Lower or no correlations of fibrosis or inflammation were found with DGE, magnetization transfer ratio, or T2R. Least Absolute Shrinkage and Selection Operator and ROC identified a composite score of MaRIA, ADC, and DGE as a very good predictor of histologic fibrosis (ROC area under the curve = 0.910). MaRIA alone was the best predictor of histologic inflammation with excellent performance in identifying active histologic inflammation (ROC area under the curve = 0.966). DISCUSSION MRE-based scores for histologic fibrosis and inflammation may assist in the characterization of CD stenosis and enable development of fibrosis-targeted therapies and clinical treatment of stenotic patients

Crohn’s Disease: Contemporary Diagnostic Techniques

The diagnosis and follow-up of patients with Crohn's disease are undergoing rapid development and innovation. In recent decades, significant diagnostic advances have been observed in diagnostic imaging. In recent years, the rapid development of new computer technologies and the introduction of new software have increased the informativeness and accuracy of CT, MRI, and ultrasound examinations of the abdomen. The quality of the CT scan is optimized, and at the same time, the ionizing dose to the patient is reduced. One of the ways to reduce the ionizing dose while scanning patients with Crohn's disease is to use a low-dose scanning protocol. With this scanning method, patients receive a much lower ionizing dose than the standard protocol without significantly losing quality. Dual-energy and dual-layer spectral detectors are two other scan protocols and image post-processing techniques that significantly improve image informativeness. New ultrasound machines and the development of the software have greatly improved the informativeness of this harmless study. Shear wave elastography and strain elastography are new research techniques through which we can obtain information about changes in the mesenteric of the affected areas. Development in magnetic resonance techniques is also observed. New magnetic resonance methods such as MR fluoroscopy, dynamic contrast-enhanced MR perfusion (DCE MR), magnetization transfer, and others are examples of this. Thus, new diagnostic methods give a key role to diagnostic imaging in the detection and follow-up of Crohn's disease

Hybrid imaging in Crohn's disease:From SPECT/CT to PET/MR and new image interpretation criteria

Crohn's disease is a chronic relapsing disease characterized by mucosal inflammation, lymphocytes infiltration and fibrotic strictures. Usually, the assessment of location, extension, inflammatory activity and severity of intestinal lesions is complex and invasive with endoscopic methods or histological and biochemical investigations. Thus, the diagnosis remains a challenge for the management of patients. Nuclear medicine techniques, in particular hybrid and molecular imaging, might offer a valid option for the evaluation and determination of the prognosis of the disease. Indeed, imaging methods provide a non-invasive, reproducible and quantitative analysis. An overview of the currently available multimodality imaging techniques in Crohn's disease are reviewed, with particular regard to positron-emission tomography/magnetic resonance and the choice of the best evaluation Score, explaining advantages and disadvantages of each one, with particular regard to their potential role for the assessment of disease activity and extent of inflammation in order to improve the diagnosis. We propose new interpretation criteria for PET/MR images