Effect of longer battery life on small bowel capsule endoscopy

AIM:To determine if longer battery life improves capsule endoscopy(CE) completion rates.METHODS:A retrospective study was performed at a tertiary,university-affiliated hospital in Vancouver,Canada.Patients who underwent CE with either PillCamTM SB2 or SB2 U between 01/2010 and 12/2013 were considered for inclusion.SB2 and SB2 U share identical physical dimensions but differ in their battery lives(8 h vs 12 h).Exclusion criteria included history of gastric or small bowel surgery,endoscopic placement of CE,interrupted view of major landmarks due to technical difficulty or significant amount of debris,and repeat CE using same system.Basic demographics,comorbidities,medications,baseline bowel habits,and previous surgeries were reviewed.Timing of major landmarks in CE were recorded,and used to calculate gastric transit time,small bowel transit time,and total recording time.A complete CE study was defined as visualization of cecum.Transit times and completion rates were compared.RESULTS:Four hundred and eight patients,including 208(51.0%) males,were included for analysis.The mean age was 55.5 ± 19.3 years.The most common indication for CE was gastrointestinal bleeding(n =254,62.3%),followed by inflammatory bowel disease(n =86,21.1%).There was no difference in gastric transit times(group difference 0.90,95%CI:0.72-1.13,P =0.352) and small bowel transit times(group difference 1.07,95%CI:0.95-1.19,P =0.261) between SB2 U and SB2,but total recording time was about 14% longer in the SB2 U group(95%CI:10%-18%,P < 0.001) and there was a corresponding trend toward higher completion rate(88.2% vs 93.2%,OR =1.78,95%CI 0.88-3.63,P =0.111).There was no statistically significant difference in the rates of positive findings(OR =0.98,95%CI:0.64-1.51,P =0.918).CONCLUSION:Extending the operating time of CE may be a simple method to improve completion rate although it does not affect the rate of positive findings.

FOCUS: Future of fecal calprotectin utility study in inflammatory bowel disease

AIM To evaluate the perspective of gastroenterologists regarding the impact of fecal calprotectin(FC) on the management of patients with inflammatory bowel disease(IBD).METHODS Patients with known IBD or symptoms suggestive of IBD for whom the physician identified that FC would be clinically useful were recruited. Physicians completed an online "pre survey" outlining their rationale for the test. After receipt of the test results, the physicians completed an online "post survey" to portray their perceived impact of the test result on patient management. Clinical outcomes for a subset of patients with follow-up data available beyond the completion of the "post survey" were collected and analyzed.RESULTS Of 373 test kits distributed, 290 were returned, resulting in 279 fully completed surveys. One hundred and ninety patients were known to have IBD; 147(77%) with Crohn's Disease, 43(21%) Ulcerative Colitis and 5(2%) IBD unclassified. Indications for FC testing included: 90(32.2%) to differentiate a new diagnosis of IBD from Irritable Bowel Syndrome(IBS), 85(30.5%) to distinguish symptoms of IBS from IBD in those known to have IBD and 104(37.2%) as an objective measure of inflammation. FC levels resulted in a change in management 51.3%(143/279) of the time which included a significant reduction in the number of colonoscopies(118) performed(P < 0.001). Overall, 97.5%(272/279) of the time, the physicians found the test sufficiently useful that they would order it again in similar situations. Follow-up data was available for 172 patients with further support for the clinical utility of FC provided.CONCLUSION The FC test effected a change in management 51.3% of the time and receipt of the result was associated with a reduction in the number of colonoscopies performed.

Verification and Dosimetric Impact of Acuros XB Algorithm for Stereotactic Body Radiation Therapy (SBRT) and RapidArc Planning for Non-Small-Cell Lung Cancer (NSCLC) Patients

Purpose: The experimental verification of the Acuros XB (AXB) algorithm was conducted in a heterogeneous rectangular slab phantom, and compared to the Anisotropic Analytical Algorithm (AAA). The dosimetric impact of the AXB for stereotactic body radiation therapy (SBRT) and RapidArc planning for 16 non-small-cell lung cancer (NSCLC) patients was assessed due to the dose recalculation from the AAA to the AXB. Methods: The calculated central axis percentage depth doses (PDD) in a heterogeneous slab phantom for an open field size of 3 ×3 cm2 were compared against the PDD measured by an ionization chamber. For 16 NSCLC patients, the dose-volume parameters from the treatment plans calculated by the AXB and the AAA were compared using identical jaw settings, leaf positions, and monitor units (MUs). Results: The results from the heterogeneous slab phantom study showed that the AXB was more accurate than the AAA;however, the dose underestimation by the AXB (up to ?3.9%) and AAA (up to ?13.5%) was observed. For a planning target volume (PTV) in the NSCLC patients, in comparison to the AAA, the AXB predicted lower mean and minimum doses by average 0.3% and 4.3% respectively, but a higher maximum dose by average 2.3%. The averaged maximum doses to the heart and spinal cord predicted by the AXB were lower by 1.3% and 2.6% respectively;whereas the doses to the lungs predicted by the AXB were higher by up to 0.5% compared to the AAA. The percentage of ipsilateral lung volume receiving at least 20 and 5 Gy (V20 and V5 respectively) were higher in the AXB plans than in the AAA plans by average 1.1% and 2.8% respectively. The AXB plans produced higher target heterogeneity by average 4.5% and lower plan conformity by average 5.8% compared to the AAA plans. Using the AXB, the PTV coverage (95% of the PTV covered by the 100% of the prescribed dose) was reduced by average 8.2% than using the AAA. The AXB plans required about 2.3% increment in the number of MUs in order to achieve the same PTV coverage as in the AAA plans. Conclusion: The AXB is more accurate to use for the dose calculations in SBRT lung plans created with a RapidArc technique;however, one should also note the reduced PTV coverage due to the dose recalculation from the AAA to the AXB.

Acuros XB Algorithm vs. Anisotropic Analytical Algorithm: A Dosimetric Study Using Heterogeneous Phantom and Computed Tomography (CT) Data Sets of Esophageal Cancer Patients

Our purpose in this study was to assess the dosimetric impact of the Acuros XB algorithm (AXB), in comparison with Anisotropic Analytical Algorithm (AAA) calculations, for esophageal cancer treatment plans created with RapidArc technique. First, we performed a phantom study by comparing the percent depth dose (PDD) calculated by AXB and AAA against the measured PDD in a slab phantom containing a 2 cmair gap thickness. Second, we performed a clinical study using a computed tomography (CT) data set from 10 esophageal cancer patients. The treatment plans calculated by AXB and AAA were evaluated for planning target volume (PTV) coverage, doses to the PTV and organs at risk (OARs). Dose calculations by the AXB and AAA were done for identical beam parameters. The AXB showed better agreement (within ±0.5%) with measurements than did the AAA (?4.9% to ?6.2%). In comparison to the AAA, the AXB predicted a higher maximum PTV dose (2.0%), but lower mean (1.1%) and minimum (2.5%) PTV doses as well as reduced PTV coverage (9.1%). The averaged mean doses to all OARs predicted by the AXB were lower (up to 3.6%), and the percentage of lungs volume receiving at least 20 and 5 Gy were lower by about 3.6% in the AXB plans compared to the AAA plans. The AXB is more accurate than the AAA for dose predictions when air medium is involved. The use of AXB is more likely to avoid dose overestimation or underestimation for the esophageal cancer treatment plans compared to AAA.

Time of infliximab therapy initiation and dose escalation in Crohn's disease

AIM:To determine if early initiation of anti-tumor necrosis factor therapy affects the need for dose escalation.METHODS:This was a retrospective review of patients receiving infliximab therapy for Crohn’s disease(CD)at two outpatient gastroenterology clinics during July2009 to October 2010.All patients included in the study were biologic agent na?ve and had moderate to severe CD(Harvey Bradshaw index>8).Patients were divided into groups based on length of time between diagnosis to therapy initiation and concurrent immunosuppressant therapy.Kaplan-Meier survival analysis was used to compare the time to dose escalation for the four groups.RESULTS:There were 68 patients,51% female and 49% male,with an average age at diagnosis of 24.7±11.9 years.The average age at infliximab initiation was 34.8±14.8 years.Of the 68 patients,19%initiated inflixiamb within 2 years of diagnosis,and 51%had concurrent immunosuppressant therapy at the time of therapy initiation.Fifty percent of patients required dose escalation and the median time from therapy initiation to dose escalation was 10 mo(interquartile range:5.3-14.8).There was a statistically significant higher probability of requiring dose esclataion in patients who initiated biologic therapy within 2 years of diagnosis,without concurrent immunosuppressant therapy(P<0.01).CONCLUSION:Those who receive infliximab within 2years of CD diagnosis require more intense immunosuppressant therapy than those who received infliximab later.

Evaluation of a deep learning supported remote diagnosis model for identification of diabetic retinopathy using wide-field Optomap

Background:We test a deep learning(DL)supported remote diagnosis approach to detect diabetic retinopathy(DR)and other referable retinal pathologies using ultra-wide-field(UWF)Optomap.Methods:Prospective,non-randomized study involving diabetic patients seen at endocrinology clinics.Non-expert imagers were trained to obtain non-dilated images using UWF Primary.Images were graded by two retina specialists and classified as DR or incidental retinal findings.Cohen’s kappa was used to test the agreement between the remote diagnosis and the gold standard exam.A novel DL model was trained to identify the presence or absence of referable pathology,and sensitivity,specificity and area under the receiver operator characteristics curve(AUROC)were used to assess its performance.Results:A total of 265 patients were enrolled,of which 241 patients were imaged(433 eyes).The mean age was 50±17 years,45%of patients were female,34%had a diagnosis of diabetes mellitus type 1,and 66%of type 2.The average Hemoglobin A1c was 8.8±2.3%,and 81%were on Insulin.Of the 433 images,404(93%)were gradable,64 patients(27%)were referred to a retina specialist,and 46(19%)were referred to comprehensive ophthalmologist for a referable retinal pathology on remote diagnosis.Cohen’s kappa was 0.58,indicating moderate agreement.Our DL algorithm achieved an accuracy of 82.8%(95%CI:80.3-85.2%),a sensitivity of 81.0%(95%CI:78.5-83.6%),specificity of 73.5%(95%CI:70.6-76.3%),and AUROC of 81.0%(95%CI:78.5-83.6%).Conclusions:UWF Primary can be used in the non-ophthalmology setting to screen for referable retinal pathology and can be successfully supported by an automated algorithm for image classification.