Citations

PurposeFiltering measured projections with a particular convolutional kernel is an essential step in analytic reconstruction of computed tomography (CT) images. A tradeoff between noise and spatial resolution exists for different choices of reconstruction kernel. In a clinical setting, this often requires producing multiple images reconstructed with different kernels for a single CT exam, which increases the burden of computation, networking, archival, and reading. We address this problem by training a deep convolutional neural network (CNN) to synthesize multiple input images into a single output image which exhibits low noise while also preserving features in images reconstructed with the sharpest kernels.MethodsA CNN architecture consisting of repeated blocks of residual units containing a total of 20 convolutional layers was used to combine features. The CNN inputs consisted of two images produced with different reconstruction kernels, one smooth and one sharp, which were stacked in the channel dimension. The network was trained using supervised learning with both full‐dose and simulated quarter‐dose abdominal CT images. After training, the performance was evaluated using a reserved set of full‐dose scans that were not used for network optimization. Noise reduction performance was measured by comparing root mean square (RMS) measurements in uniform regions. Spatial resolution was compared using line profiles of anatomic features.ResultsFor the regions tested, the synthetic images feature noise levels slightly below those of the smooth input images, while maintaining the resolution of anatomic details found in the sharp input images.ConclusionsA deep CNN can be used combine features from CT images reconstructed with different kernels to produce a single synthesized image series that exhibits both low noise and high spatial resolution. This approach has implications for improving image quality, reducing radiation dose, and simplifying the clinical workflow for CT imaging.

Abstract Background and Aims Our goal was to determine the importance of ileal inflammation at computed tomography or magnetic resonance enterography in Crohn’s disease patients with normal ileoscopy. Methods Patients with negative ileoscopy and biopsy within 30 days of CT or MR enterography showing ileal inflammation were included. The severity [0–3 scale] and length of inflammation within the distal 20 cm of the terminal ileum were assessed on enterography. Subsequent medical records were reviewed for ensuing surgery, ulceration at ileoscopy, histological inflammation, or new or worsening ileal inflammation or stricture on enterography. Imaging findings were classified as: Confirmed Progression [subsequent surgery or radiological worsening, new ulcers at ileoscopy or positive histology]; Radiologic Response [decreased inflammation with medical therapy]; or Unlikely/Unconfirmed Inflammation. Results Of 1471 patients undergoing enterography and ileoscopy, 112 [8%] had imaging findings of inflammation with negative ileoscopy, and 88 [6%] had negative ileoscopy and ileal biopsy. Half [50%; 44/88] with negative biopsy had moderate/severe inflammation at enterography, with 45%, 32% and 11% having proximal small bowel inflammation, stricture or fistulas, respectively. Two-thirds with negative biopsy [67%; 59/88] had Confirmed Progression, with 68%, 70% and 61% having subsequent surgical resection, radiological worsening or ulcers at subsequent ileoscopy, respectively. Mean length and severity of ileal inflammation in these patients was 10 cm and 1.6. Thirteen [15%] patients had Radiologic Response, and 16 [18%] had Unlikely/Unconfirmed Inflammation. Conclusion Crohn’s disease patients with unequivocal imaging findings of ileal inflammation at enterography despite negative ileoscopy and biopsy are likely to have active inflammatory Crohn’s disease. Disease detected by imaging may worsen over time or respond to medical therapy.

Abstract Background Crohn’s rectovaginal fistulizing disease remains notoriously difficult to treat. A phase I clinical trial to evaluate the safety and feasibility of a novel protocol using a mesenchymal stem cell (MSC)–coated Gore Bio-A fistula plug for the treatment of medically and surgically refractory Crohn’s rectovaginal fistulas was conducted. Methods Five patients underwent an autologous subcutaneous adipose tissue harvest via a 2-cm abdominal wall incision at time of exam under anesthesia (EUA) with seton placement. MSCs were isolated, expanded, and impregnated on the plug. After 6 weeks, patients returned to the operating room for placement of the MSC-coated plug. The primary end points were safety and feasibility; the secondary end point was clinical and radiographic healing at 6 months. Results Five female patients (median age [range], 49 [38–53] years) with a median disease duration (range) of 23 (7–34) years who were on biologic (n = 5) or combination therapy (n = 3) had successful harvest and expansion of MSCs and delivery of the Gore Bio-A plug. There were no serious adverse events or adverse events related to the MSCs or plug during the 6-month follow-up. At 6 months, 3 patients had complete cessation of drainage, and 2 had >50% reduction in drainage; all had a persistent fistula tract identified on magnetic resonance imaging and EUA at 6 months. Conclusions Surgical placement of an autologous adipose-derived MSC-coated fistula plug in diverted patients with Crohn’s rectovaginal fistulas was safe and feasible. All patients had a reduction in the size of their fistula tract, and 3 of 5 had cessation of drainage, but none achieved complete healing. This was a phase I clinical trial of autologous mesenchymal stem cells on a plug for rectovaginal Crohn’s fistulas.

Abstract Background We aim to assess the impact of a multidisciplinary inflammatory bowel disease (IBD) conference on the management of patients with complex IBD. Methods Data were collected during each conference from February 2017 through October 2018 with chart review performed at 6 months to determine if conference recommendations were successfully implemented. Results Eighty-five patients were discussed. The presenting diagnosis was changed by 11.8%. Recommendations for further testing, medical therapy, and surgery were successfully implemented in 77.1%, 98.1%, and 88.4%, respectively. Conclusions This study supports the role of IBD multidisciplinary conferences in the management of patients with complex IBD.

Objective The aim of this study was to determine if computed tomography (CT) angiography using an individualized transition delay (CTA-ID) would facilitate reductions in injection rate and iodine dose. Methods The CTA-ID was performed in 20 patients with routine injection rate and iodine dose; 20 patients with injection rate lowered by 1 mL/s; and 40 patients with injection rate lowered by 1 mL/s with 29% less iodine. Routine CTAs in the same or size-matched patients served as controls. Diagnostic image quality and intra-arterial CT numbers were assessed. Results The median transition delay between aortic threshold and CTA-ID image acquisition was significantly longer than with conventional bolus tracking (mean increase, 13.3 seconds; P < 0.0001), with image quality being the same or better. Intra-arterial CT numbers were 200 Hounsfield units or greater for 80 of 80 CTA-ID, but not for 6 of 49 (12%) internal control or for 11 of 80 (14%) size-matched control patients. Conclusion The CTA-ID bolus-tracking software alters transition delays to permit diagnostic CTA examinations despite slower injection rate and less iodine.

Abstract Background The decision to either escalate medical therapy or proceed to ileocecal resection (ICR) in patients with terminal ileal Crohn disease (CD) remains largely subjective. We sought to develop a risk score for predicting ICR at 1 year from computed tomography or magnetic resonance enterography (CTE/MRE). Methods We conducted a retrospective cohort study including all consecutive adult (> 18 years) patients with imaging findings of terminal ileal CD (Montreal classification: B1, inflammatory predominant; B2, stricturing; or B3, penetrating) on CTE/MRE between January 1, 2016, and December 31, 2016. The risk for ICR at 6 months and at 1 year of CTE/MRE and risk factors associated with ICR, including demographics, CD-specific immunosuppressive therapeutics, and disease presentation at the time of imaging, were determined. Results Of 559 patients, 121 (21.6%) underwent ICR during follow-up (1.4 years [IQR 0.21–1.64 years]); the risk for ICR at 6 months and at 1 year was 18.2% (95% CI 14.7%–21.6%) and 20.5% (95% CI 16.8%–24.1%), respectively. Multivariable analysis revealed Montreal classification (B2, hazard ratio [HR] 2.73, and B3, HR 6.80, both P < 0.0001), upstream bowel dilation (HR 3.06, P < 0.0001), and younger age (19–29 years reference, 30–44 years, HR 0.83 [P = 0.40]; 45–59 years, HR 0.58 [P = 0.04], and 60+ years, HR 0.45 [P = 0.01]) to significantly increase the likelihood of ICR. A predictive nomogram for interval ICR was developed based on these significant variables. Conclusions The presence of CD strictures, penetrating complications, and upstream bowel dilation on CTE/MRE, combined with young age, significantly predict ICR. The suggested risk model may facilitate objective therapeutic decision-making.

AbstractBackgroundDuring proctography, rectal emptying is visually estimated by the reduction in rectal area. The correlation between changes in rectal area, which is a surrogate measure of volume, is unclear. Our aims were to compare the change in rectal area and volume during magnetic resonance (MR) proctography and to compare these parameters with rectal balloon expulsion time (BET).MethodsIn 49 healthy and 46 constipated participants, we measured BET and rectal area and volume with a software program before and after participants expelled rectal gel during proctography.Key ResultsAll participants completed both tests; six healthy and 17 constipated patients had a prolonged (>60 seconds) BET. During evacuation, the reduction in rectal area and volume was lower in participants with an abnormal than a normal BET (P < 0.01). The reduction in rectal area and volume were strongly correlated (r = 0.93, P < 0.001) and equivalent for identifying participants with abnormal BET. Among participants with less evacuation, the reduction in rectal area underestimated the reduction in rectal volume. A rectocele larger than 2 cm was observed in eight of 18 (44%) participants in whom the difference between change in volume and area was ˃10% but only 14 of 77 (18%) participants in whom the difference was ≤10% (P = 0.03).ConclusionsMeasured with MR proctography, the rectal area is reasonably accurate for quantifying rectal emptying and equivalent to rectal volume for distinguishing between normal and abnormal BET. When evacuation is reduced, the change in rectal area may underestimate the change in rectal volume.

Patients with Crohn’s disease commonly develop ileal and less commonly colonic strictures, containing various degrees of inflammation and fibrosis. While predominantly inflammatory strictures may benefit from a medical anti-inflammatory treatment, predominantly fibrotic strictures currently require endoscopic balloon dilation or surgery. Therefore, differentiation of the main components of a stricturing lesion is key for defining the therapeutic management. The role of endoscopy to diagnose the nature of strictures is limited by the superficial inspection of the intestinal mucosa, the lack of depth of mucosal biopsies and by the risk of sampling error due to a heterogeneous distribution of inflammation and fibrosis within a stricturing lesion. These limitations may be in part overcome by cross-sectional imaging techniques such as ultrasound, CT and MRI, allowing for a full thickness evaluation of the bowel wall and associated abnormalities. This systematic literature review provides a comprehensive summary of currently used radiologic definitions of strictures. It discusses, by assessing only manuscripts with histopathology as a gold standard, the accuracy for diagnosis of the respective modalities as well as their capability to characterise strictures in terms of inflammation and fibrosis. Definitions for strictures on cross-sectional imaging are heterogeneous; however, accuracy for stricture diagnosis is very high. Although conventional cross-sectional imaging techniques have been reported to distinguish inflammation from fibrosis and grade their severity, they are not sufficiently accurate for use in routine clinical practice. Finally, we present recent consensus recommendations and highlight experimental techniques that may overcome the limitations of current technologies.