Diagnostic performance in gastric cancer is higher using endocytoscopy with narrow-band imaging than using magnifying endoscopy with narrow-band imaging.

BACKGROUND: For diagnosing gastric cancer, differences in the diagnostic performance between endocytoscopy with narrow-band imaging and magnifying endoscopy with narrow-band imaging have not been reported. We aimed to clarify these differences by analyzing diagnoses made by endoscopists in Japan. METHODS: This single-center retrospective cohort study used 106 cancerous and 106 non-cancerous images obtained via both modalities (total, 424 images) for diagnosis. Sixty-one endoscopists with varying experience levels from 45 institutions were included. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated to determine the diagnostic performance of each modality and compared using the Mann-Whitney U test. RESULTS: Among all endoscopists, diagnostic accuracy, sensitivity, positive predictive value, and negative predictive value were higher with endocytoscopy with narrow-band imaging than with magnifying endoscopy with narrow-band imaging (percentage [95% confidence interval]: 78.8% [76.4-83.0%] versus 72.2% [69.3-73.6%], p < 0.0001; 82.1% [78.3-85.9%] versus 64.2% [60.4-69.8%], p < 0.0001; 88.7% [82.6-90.7%] versus 78.5% [75.4-85.1%], p = 0.0023; 79.0% [75.3-80.5%] versus 68.5% [66.4-71.6%], p < 0.0001, respectively). In the magnifying endoscopy with narrow-band imaging-trained group, these values were also higher with endocytoscopy with narrow-band imaging than with magnifying endoscopy with narrow-band imaging (p < 0.0001, p = 0.0001, p = 0.0143, and p < 0.0001, respectively). Diagnostic accuracy, sensitivity, and negative predictive value were higher with endocytoscopy with narrow-band imaging than with magnifying endoscopy with narrow-band imaging in the magnifying endoscopy with narrow-band imaging-untrained group (p = 0.0041, p = 0.0049, and p = 0.0098, respectively). CONCLUSIONS: Diagnostic performance was higher using endocytoscopy with narrow-band imaging than using magnifying endoscopy with narrow-band imaging. Our results may help change the technique used to diagnose gastric cancer.

Convolutional Neural Network for Differentiating Gastric Cancer from Gastritis Using Magnified Endoscopy with Narrow Band Imaging.

BACKGROUND: Early detection of early gastric cancer (EGC) allows for less invasive cancer treatment. However, differentiating EGC from gastritis remains challenging. Although magnifying endoscopy with narrow band imaging (ME-NBI) is useful for differentiating EGC from gastritis, this skill takes substantial effort. Since the development of the ability to convolve the image while maintaining the characteristics of the input image (convolution neural network: CNN), allowing the classification of the input image (CNN system), the image recognition ability of CNN has dramatically improved. AIMS: To explore the diagnostic ability of the CNN system with ME-NBI for differentiating between EGC and gastritis. METHODS: A 22-layer CNN system was pre-trained using 1492 EGC and 1078 gastritis images from ME-NBI. A separate test data set (151 EGC and 107 gastritis images based on ME-NBI) was used to evaluate the diagnostic ability [accuracy, sensitivity, positive predictive value (PPV), and negative predictive value (NPV)] of the CNN system. RESULTS: The accuracy of the CNN system with ME-NBI images was 85.3%, with 220 of the 258 images being correctly diagnosed. The method's sensitivity, specificity, PPV, and NPV were 95.4%, 71.0%, 82.3%, and 91.7%, respectively. Seven of the 151 EGC images were recognized as gastritis, whereas 31 of the 107 gastritis images were recognized as EGC. The overall test speed was 51.83 images/s (0.02 s/image). CONCLUSIONS: The CNN system with ME-NBI can differentiate between EGC and gastritis in a short time with high sensitivity and NPV. Thus, the CNN system may complement current clinical practice of diagnosis with ME-NBI.

Influence of calibration on digital templating of hip arthroplasty.

INTRODUCTION: Digital templating for total joint replacement is the current standard. For image calibration, external calibration markers (ECM) are used. However, there are concerns regarding the precision of the method. This study aimed to identify the direct influence of calibration errors on digital templating. PATIENTS AND METHODS: A retrospective analysis of 100 post-operative radiographs with unilateral total hip arthroplasty was performed. The magnification factor of the ECM and of the internal prosthetic femoral head (ICM) as a reference value was calculated for each radiograph. Two blinded observers performed templating of the contralateral hip using a randomized list for all radiographs and both markers. The component size templated by the ECM magnification was compared to the reference by the ICM magnification. RESULTS: Mean magnification factors of ICM and ECM differed significantly (p = 0.006). The absolute difference was 5.2% (range 0.0-23.3%, SD 4.8%). Templating of the acetabular or the femoral component showed no significant differences (p = 0.120, p = 0.599). Differences of more than one size were found in 26% of the acetabular components and 14% of the femoral components and differences over two sizes in 10% respectively 3%. Correlation coefficients for magnification error and size differences of acetabular components were - 0.645 (p < 0.001) and for the femoral component - 0.607 (p < 0.001). INTERPRETATION: The calibration error of external calibration markers in digital templating for hip replacement influences component sizes significantly. Thus, correct positioning of ECM is of utmost importance.

Comparison between Magnification Techniques and Direct Vision in Thyroid Surgery: A Systematic Review and Meta-Analysis.

Background and Objectives: The most common complications after conventional thyroid surgery in adult patients are recurrent laryngeal nerve (RLN) injury and hypocalcemia. Magnification techniques (surgical loupes or surgical microscope) are used for identification of RLN and parathyroid glands to diminish these complications although more evidence is necessary to assess their safety and efficacy in comparison with direct vision. Methods and Materials: Electronic databases (Pubmed, Cochrane Library, Scopus) as well as gray literature sources were searched for randomized controlled trials (RCTs) comparing the frequency of transient/permanent RLN injury and hypocalcemia after thyroid surgery by using magnification techniques and direct vision for identification of RLN and parathyroid glands until October 17, 2019. The main outcomes were transient/permanent RLN injury and hypocalcemia. For all outcomes, 95% confidence intervals (95% CI) were used. Statistical analysis was performed with RevMan 5.3. Results: Systematic review and meta-analysis included 3 RCTs with 437 patients overall. Magnification techniques did not significantly affect the risk of occurrence of transient RLN injury (OR = 0.38, 95% CI (0.11-1.35), I2 = 0%) and transient hypocalcemia (OR = 0.31, 95% CI (0.09-1.09), I2 = 23%) compared with direct vision. Included RCTs demonstrated only two patients with permanent hypocalcemia and another one with permanent RLN injury, who belonged to the direct vision group. Conclusion: The use of magnification techniques for identification of RLN and parathyroid glands seems to be as safe as direct vision. However, they do not decrease the risk of RLN injury and transient hypocalcemia after thyroid surgery compared with direct vision. Finally, further prospective research should be conducted as the sample among the studies was small.

Clinical impact of surveillance colonoscopy using magnification without diminutive polyp removal.

BACKGROUND AND AIM: In Western countries, endoscopic removal of all adenomas during colonoscopy is recommended. The present study evaluates the usefulness of magnifying colonoscopy without removal of diminutive (≤5 mm) colorectal polyps. METHODS: Patients with diminutive polyps who were observed for over 5 years using magnification at Hiroshima University Hospital were selected retrospectively. Lesions ≥6 mm in size, depressed lesions, and lesions with type V pit pattern were indications for endoscopic resection. We investigated the characteristics of lesions indicated for endoscopic resection detected on surveillance colonoscopy and the risk factors for the incidence of lesions indicated for endoscopic resection. RESULTS: A total of 706 consecutive patients were enrolled. Sixty-eight lesions indicated for endoscopic resection were detected, averaging 9.0 ± 4.8 mm, and 33 (49%) lesions were located in the right colon. Pathological diagnoses were adenoma, Tis carcinoma, and T1 carcinoma in 58 (85%), eight (12%), and two (3%) lesions, respectively. Five lesions were considered to grow from previously detected diminutive polyps. Relative risks for the incidence of a lesion indicated for endoscopic resection were 1.76 (95% confidence interval [CI], 1.004-3.23) for males compared with females, 3.76 (95% CI, 2.03-7.50) for more than three polyps at initial colonoscopy compared with one polyp, and 2.84 (95% CI, 1.43-5.24) for patients with carcinoma at initial colonoscopy compared with patients with no lesion indicated for endoscopic resection. Nine carcinomas were resected endoscopically. CONCLUSION: Diminutive low-grade adenomas detected by using magnifying colonoscopy may not necessarily require removal.

Prospective, Randomized, Surgeon-Blinded Comparison of Standard Magnification Assumption vs Magnification Marker Usage for Preoperative Templating in Total Hip Arthroplasty.

BACKGROUND: We undertook this prospective, randomized, surgeon-blinded study to compare the accuracy of using of a magnification marker on preoperative radiographs for templating vs using a standard 21% magnification. METHODS: One hundred consecutive total hip arthroplasties were randomized to preoperative templating using a 25-mm magnification marker (50 patients) or a standard 21% magnification (50 patients). Intraoperative data were collected regarding the actual and predicted size of the femoral and acetabular components. RESULTS: The 2 groups were found to be comparable with respect to body mass index (28.9 vs 27.9, P = .26) and gender (P = .69). In the magnification marker group, we predicted the femoral size within 1 size in 80% of the cases and the acetabular component in 94%. In the group of a standard 21% magnification, we predicted the femoral size within 1 size in 90% of the cases and the acetabular component in 96%. These proportions did not statistically differ (femur: χ2P = .16, odds ratio = 2.3, 95% confidence interval = 0.7-7.1; acetabulum: χ2P = .65, odds ratio = 1.5, 95% confidence interval = 0.3-9.6). CONCLUSION: We did not detect a statistically significant difference in accuracy by using one method over the other when comparing the accuracy of component size selection. As the use of the magnification marker adds to the time and expense of preoperative radiographic acquisition, we feel using a standard 21% magnification is an equally accurate technique.

Magnification endoscopy with acetic acid enhancement and a narrow-band imaging system for pit pattern diagnosis of colorectal neoplasms.

BACKGROUND AND GOALS: Pit pattern (PP) analysis of colorectal neoplasms using magnification chromoendoscopy with crystal violet (CV-MCE) is useful for predicting histologic features, but it is time consuming. Capillary pattern analysis by magnification endoscopy with narrow-band imaging (NBIME) is a useful and simpler procedure, but its diagnostic accuracy may be inferior to CV-MCE. NBIME with acetic acid enhancement (A-NBIME) is effective for rapid visualization of gastric mucosal microstructures. We performed a prospective study to compare the diagnostic reliability and feasibility of A-NBIME and CV-MCE in PP diagnosis of colorectal neoplasms. STUDY: The present study consisted of 3 protocols: Study-1 assessed 56 colorectal lesions photographed with A-NBIME and CV-MCE, and the endoscopic images were reviewed by 3 experts to compare the diagnostic concordance; study-2 assessed 202 colorectal lesions photographed with A-NBIME in 116 consecutive patients and the correlation between PP and histologic findings; study-3 randomly allocated 100 patients with colorectal lesions equally to A-NBIME and CV-MCE, and compared the procedure time and visible ratio of PP. RESULTS: The κ value for interobserver agreement for A-NBIME and CV-MCE was 0.71 (0.66 to 0.75) and 0.80 (0.75 to 0.85), respectively. Intraobserver agreement between modalities for each reviewer was 0.79 (0.70 to 0.88), 0.80 (0.71 to 0.90), and 0.74 (0.67 to 0.82). Non-neoplastic polyps and massively invasive submucosal adenocarcinomas were statistically related to type II and type VI-H/VN. The procedure time was statistically shorter with A-NBIME than with CV-MCE (31 vs. 81 s), and the visible ratio of PP was equivalent (98.9% vs. 98.3%). CONCLUSIONS: A-NBIME is comparable with CV-MCE in PP diagnosis of colorectal neoplasms and is a simpler technique.

Endocytoscopic observation of various esophageal lesions at ×600: can nuclear abnormality be recognized?

Endocytoscopy (ECS) is a novel endoscopic technique that allows detailed diagnostic examination of the gastrointestinal tract at the cellular level. We previously reported that use of ECS at ×380 magnification (GIF-Y0002) allowed a pathologist to diagnose esophageal squamous cell carcinoma (ESCC) with high sensitivity (94.9%) but considerably low specificity (46.7%) because this low magnification did not reveal information about nuclear abnormality. In the present study, we used the same magnifying endoscope to observe various esophageal lesions, but employed digital 1.6-fold magnification to achieve an effective magnification of ×600, and evaluated whether this improved the diagnostic accuracy in distinguishing neoplastic from non-neoplastic lesions.We examined the morphology of surface cells using vital staining with toluidine blue and compared the histological features of 40 cases, including 19 case of ESCC and 21 non-neoplastic esophageal lesions (18 cases of esophagitis, 1 case of glycogenic acanthosis, 1 case of leiomyoma, and 1 case of normal squamous epithelium). One endoscopist classified the lesions using the type classification, and we consulted one pathologist for judgment of the ECS images as 'neoplastic', 'borderline', or 'non-neoplastic'. At ×600 magnification, the pathologist confirmed that nuclear abnormality became evident, in addition to the information about nuclear density provided by observation at ×380. The overall sensitivity and specificity with which the endoscopist was able to predict neoplastic lesions using the type classification was 100% (19/19) and 90.5% (19/21), respectively, in comparison with values of 94.7% (18/19 cases) and 76.2% (16/21), respectively, for the pathologist using a magnification of ×600. The pathologist diagnosed two non-neoplastic lesions and one case of ESCC showing an apparent increase of nuclear density with weak nuclear abnormality as 'borderline'. Among the 21 non-cancerous lesions, two cases of esophagitis that were misdiagnosed by the endoscopist were also misinterpreted as 'neoplastic' by the pathologist. We have shown, by consultation with a pathologist, that an ECS magnification of ×600 (on a 19-inch monitor) is adequate for recognition of nuclear abnormality. We consider that it is feasible to diagnose esophageal neoplasms on the basis of ECS images, and that biopsy histology can be omitted if a combination of increased nuclear density and nuclear abnormality is observed.

The use of digital magnification to reduce radiation dose in the cardiac catheter laboratory.

OBJECTIVES: To audit whether using magnification of images by use of a large viewing screen using digital matrix magnification which enlarges the image by 33% without using the X-ray machine zoom magnification protocols on a Siemens Artis Zee X-ray machine in a cardiac catheter laboratory results in a reduction of kerma-area product (KAP) for both diagnostic and interventional procedures. This reduction was predicted in an in vitro study in our laboratory, which has previously shown a 20.4% reduction in KAP. METHODS: A retrospective analysis was conducted of the radiation exposure to compare the measured KAP recorded during the period when conventional magnification with automatic brightness and dose control was used on a Siemens Artis Zee X-ray machine with a flat panel detector and when magnification settings were avoided by using a large screen to enlarge and project a non-magnified image by digital magnification. The analysis was carried out for patients having a diagnostic coronary angiogram and those having an interventional coronary procedure. RESULTS: For diagnostic coronary angiograms the median KAP per procedure in the period using conventional magnification was 2124.5 µGy.m2 compared to 1401 µGy.m2 when image matrix magnification was used, a 34% reduction (p < 0.0001). For interventional coronary procedures, the median KAP per procedure in the period using conventional magnification was 3791 µGy.m2 compared to 2568.5 µGy.m2 when image matrix magnification was used, a 32% reduction (p < 0.0001). CONCLUSION: Avoiding using conventional magnification in the cardiac catheter laboratory and using a large screen to magnify images was associated with a statistically significant greater than 30% reduction in KAP. ADVANCES IN KNOWLEDGE: This paper is the proof in clinical practice of a theoretical conclusion that radiation dose (KAP) is reduced by use of Image matrix magnification using a large viewing screen without the need to use X-ray tube magnification without significant loss of image resolution in interventional cardiology. The same approach will be useful in interventional radiology.

Reliability of the vertical magnification factor on panoramic radiographs: clinical implications for posterior mandibular implants.

OBJECTIVES: Panoramic radiographs allow evaluation of the available bone height for implant treatment planning while imparting a low radiation dose. As panoramic radiography produces image distortion, reference objects are required to determine the exact magnification. This study aims to estimate a panoramic unit's vertical magnification factor (MF) by measuring the length of dental implants used as radiopaque reference objects on postoperative panoramic radiographs. We compared our findings to the vertical MF listed by the panoramic unit manufacturer, and studied the reproducibility and accuracy of our measuring method by analyzing the inter- and intraobserver agreements. MATERIAL AND METHODS: Using a digital calliper, we measured the length of 32 implants on 17 postoperative panoramic radiographs taken with a Scanora unit. The implants were 10mm-long standard Straumann implants placed in the posterior segments of mandibles. The MF was calculated by dividing the implant's radiological length by the implant's real length. RESULTS: The mean calculated vertical MF was 1.27 ± 0.01 (1.245-1.295) and was lower than the manufacturer's MF (1.3). The vertical MF was 1.28 ± 0.01 in the premolar and 1.27 ± 0.01 in the molar regions. There was an excellent intraobserver reliability (0.96 for observer 1; 0.93 for observer 2) and a good interobserver reliability (0.85 at measurement session 1; 0.8 at measurement session 2) CONCLUSIONS: The observed reliability of the MF confirms that a panoramic radiograph can be used for preoperative implant length evaluation in the posterior mandibular segments. MF stability should be verified with other panoramic units. In clinical practice, using the implant length as a reference object on postoperative panoramic radiographs is a simple and effective evaluation method to estimate a panoramic unit's MF.

[Comparison between electronic zoom and geometric magnification of clusters of microcalcifications on digital mammography]. / Comparaison entre le zoom numérique et l'agrandissement géométrique dans l'étude des foyers de microcalcifications en mammographie numérique.

PURPOSE: With the advent of digital mammography with electronic zoom capabilities, we have sought to determine the need for geometric magnification for the evaluation of clusters of microcalcifications. PATIENTS AND METHODS: Eighty-eight clusters of microcalcifications were reviewed by two experienced radiologists using electronic zoom (ZOOM) and geometric magnification (MAG). The following criteria were evaluated: image quality, shape and number of microcalcifications, size and shape of the clusters. The clusters were classified based on malignancy risk using the BI-RADS criteria. Histological results from macrobiopsy or surgery as well as 2 year follow-up were used as reference for statistical analysis. RESULTS: Sensitivity (100% for MAG and 90% for ZOOM), specificity (52% versus 39%), positive predictive value (51% versus 44%) and negative predictive value (100% versus 88%) were superior for geometric magnification compared to electronic zoom irrespective of the reviewer but without reaching statistical significance. However, image quality was significantly superior with geometric magnification (p<<0.05). In addition, reviewers were more confident in their interpretation of geometric magnification images. CONCLUSION: Geometric magnification remains necessary in routine clinical practice for the characterization of microcalcifications and BI-RADS classification.

Digital zoom is a useful, simple, and cost-effective method of reducing radiation exposure in percutaneous coronary intervention.

Reducing radiation exposure is a very important issue in interventional cardiology techniques such as percutaneous coronary intervention. Although novel techniques to reduce radiation exposure are valuable, we should also reconsider older techniques. Digital zoom has been available in Japan from 2005. Digital zoom enlarges an 8-inch field of view (FOV) by 1.2 times, allowing visualization of a 6.7-inch FOV without FOV switching. We identified 2101 suitable cases of percutaneous intervention (PCI) and divided them into two groups according to the use of digital zoom; 1195 patients were included in the digital zoom group and 906 patients in the conventional group. We collected data regarding the reference air kerma (RAK) and dose-area product (DAP). We calculated RAK and DAP per minute fluoroscope time (RAK/min, DAP/min, respectively). There were intergroup differences in RAK, DAP, RAK/min, and DAP/min (digital zoom group vs conventional group; RAK, 1590 mGy [990-2410] vs 1850 [1220-2720], p < 0.01, RAK/min; 54.7 mGy/min [38.5-73.2] vs 71.2 [51.5-93.0], p < 0.01; DAP, 16,000 cGy × cm2 [10,300-24,400] vs 20,700 [13,400-29,500], p < 0.001; DAP/min, 557 cGy × cm2/min [392-737] vs 782 [571-1010], p < 0.01, respectively). Because of baseline differences between the two groups, we performed propensity score matching. Even after score matching, there were intergroup differences in DAP, DAP/min, RAK, and RAK/min. Furthermore, the least squares method showed that digital zoom is a significant predictor of RAK (ß = 0.14, p < 0.01) and DAP (ß = 0.20, p < 0.01). Digital zoom is an older cost-effective technique that can significantly reduce radiation exposure in PCI.

Correcting fan-beam magnification in clinical densitometry scans of growing subjects.

As children grow, body and limb girths increase. For serial densitometric measurements, growth increases the distance between the bone region of interest and X-ray source over time, thereby increasing fan-beam magnification. To isolate bone accrual from magnification error in growing subjects, we developed a correction method based on waist girth, a common anthropometric measure. This correction was applied to dual-energy X-ray absorptiometry output obtained in a cohort of premenarcheal gymnasts and nongymnasts. After correcting for magnification, results for projected area and bone mineral content (BMC) increased by 0.4-1.1% at the lumbar spine and 8-16% at the femoral neck, decreasing areal bone mineral density (aBMD) by 0.4-2.3% at both sites. The effects of magnification correction were similar in magnitude to BMC and aBMD gains previously reported in longitudinal studies of normoactive children. Because of body size differences, the effect of correction for BMC and aBMD was 10-20% greater in nongymnasts than in gymnasts, which increased the observed aBMD differential between gymnasts and nongymnasts. Fan-beam magnification distorts true changes in bone mineral measures in growing premenarcheal girls and, therefore, may obscure additional activity-related changes during growth. Our correction technique may enhance detection of skeletal adaptation, particularly in pediatric populations.

An Assesment of Usefulness of Smartphone as a Magnifying Device for Microsurgery Training.

BACKGROUND: Currently available smartphones are equipped with optic systems allowing even 10x magnifi-ca-tion, which makes it possible to use them as magnifying devices for microsurgery training. The objective of this study was to assess the usefulness of smartphones for basic microsurgery training. MATERIAL AND METHODS: Two students began experimental microsurgical training using a smartphone as a magni-fy-ing device. Both students had acquired microsurgical skills following training under the microscope. For the expe-riment, the time of completion of a "6 stitches" test was measured and compared for each student using a smartphone and a microscope, after 1 and 6 hours of training using only a smartphone. RESULTS: After one hour of training, the first student completed the "6 stitches" test within 7:52 min. under the mi-croscope and within 16:35 min. using a smartphone, while the respective scores of the second student were 12:31 and 20:12 min.. In both cases the time required to complete the test was longer when working with a smartphone. The test was repeated after 6 hours of practice with a telephone, and the results now were as follows: first student 7:10 min. with the microscope and 12:50 min. with a smartphone, second student 8:54 min. with the microscope and 12:01 min. with a smartphone. CONCLUSIONS: 1. The microsurgical skills of both trainees improved gradually when they were using a smartphone (by 3:8 min. and 8:1 min) and the microscope (by 0:4 min. and 3:8 min). 2. Two drawbacks of the smartphone were noticed: lack of three-dimensional vision, deteriorating vertical orientation in the operating field and worse vision quality compared to the microscope. 3. Advantages of this tool include the availability of training at home, low cost and possibility of analysis of images recorded in the smartphone memory.

Improving the accuracy of digital templating: achieving success through stakeholder management.

The use of a marker ball in digital templating for hip arthroplasty is a well-established method of preoperative planning and is used to overcome the inherent magnification in plain film radiographs. Our hospital policy is to place a marker ball in all anteroposterior pelvic films taken in the emergency department (ED) which have been requested for suspected neck of femur fractures. We carried out a baseline measurement followed by three Plan-Do-Study-Act cycles for all pelvic films taken in ED during July 2016, November 2016, February 2017 and November 2017. Interventions between the baseline measurement and cycle 1 were to educate the lead radiographer and publish the results in the radiology newsletter, and between cycles 1 and 2 was to run a teaching session for radiographers, display posters in the X-ray department and place an electronic prompt on the X-ray machine to alert them of the need to place a marker ball in the X-ray field. Cycle 3 looked to see if improvements were sustained. 16/81 (20%) radiographs complied with the policy in our baseline measurement; 25/51 (46%, p=0.002) in cycle 1; 40/54 (74%, p=0.0056) in cycle 2; and 48/63 (76%) in cycle 3. Our quality improvement project led to large improvements in clinical practice through straightforward, small, but appropriately targeted interventions. Stakeholder management is key to successfully implementing change. The next step is to switch from the VoyantMark to the KingMark marker ball, as it has greater accuracy of templating and is also easier to place within the field of an X-ray.

Comparative study of magnifying narrow-band imaging and conventional white light endoscopy in the diagnosis of Helicobacter pylori status after eradication therapy.

Predicting Helicobacter pylori (Hp) status by endoscopic finding would be useful in recent clinical condition that the use of proton-pump inhibitors, anti-platelet, and anti-coagulant have become widespread. We aimed to elucidate the diagnostic accuracy of magnifying narrow-band imaging (M-NBI) endoscopy in distinguishing Hp status in patients with or without history of successful Hp eradication and compare this accuracy to the diagnostic accuracy of conventional white light (WL) endoscopy.Two hundred seven endoscopic examinations before and after Hp eradication were performed in prospective 163 patients. Endoscopic images by using the M-NBI and conventional WL were stored electronically and randomly allocated to 2 readers for evaluation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were assessed by reference to Hp status assessed by conventional clinical test.Sensitivity, specificity, PPV, NPV, and accuracy for predicting Hp status for the conventional WL was 72.2%, 75.5%, 72.2%, 75.5%, and 73.9% for the first reader; 86.6%, 57.3%, 64.1%, 82.9%, and 71.0% for the second reader. On the other hand, sensitivity, specificity, PPV, NPV, and accuracy for predicting Hp status for the M-NBI was 96.9%, 93.6%, 93.1%, 97.1%, and 95.2% for the first reader; 92.8%, 93.6%, 92.8%, 93.6%, and 93.2% for the second reader, respectively. The diagnostic accuracy of M-NBI was significantly higher than that of WL (P < .0001 for both readers). Inter-observer agreement of M-NBI (k = 0.83) was also better than that of WL (k = 0.53).M-NBI was capable of distinguishing Hp status before and after eradication therapy.

Monte Carlo studies on the influence of focal spot size and intensity distribution on spatial resolution in magnification mammography.

Magnification is a special technique applied in mammography in cases where breast complaints have already been noticed, aiming to examine a specific area of the breast. Small-sized focal spots are essential in such techniques in order to reduce the resultant geometrical unsharpness. The x-ray intensity distribution of the focal spot is another crucial parameter for such a technique as it affects the mammographic resolution. In this study a Monte Carlo simulation model is utilized, in order to examine the effect of a wide range of focal spot sizes and three representative intensity distributions on spatial resolution under magnification. A thick sharp edge consisting of lead, non-transparent to x-rays was imaged under various conditions for this purpose, and the corresponding spatial resolution was calculated through the modulation transfer function (MTF). Results demonstrate that focal spots larger than 0.10 mm can mainly be used for low degrees of magnification, especially when combined with double peak Gaussian intensity distribution of the focal spot (sum of two single peak Gaussian distributions with different centers), as the resultant spatial resolution is not as high as the corresponding from smaller foci or uniform and single peak Gaussian distributions. Moreover, for the degrees of magnification usually utilized in clinical practice they do not reach the acceptable limit of 12 lp mm(-1). The replacement of the x-ray tube when the focal spot starts being destroyed is very crucial as the possible alteration of single peak Gaussian distribution to double peak Gaussian results in the degradation of spatial resolution. A focal spot of 0.10 mm or smaller, combined with single peak Gaussian intensity distribution, can be considered appropriate even for higher degrees of magnification and its use can contribute in the effort to optimize the magnification views in mammography.

Comparison of fusion assessment techniques: computer-assisted versus manual measurements.

OBJECT: Fusion assessment after cervical arthrodesis can be subjective. Measures such as bridging bone quantification or extent of (limited) motion on dynamic studies are common but difficult to interpret and fraught with biases. We compared manual measurement and computer-assisted techniques in assessing fusion after anterior cervical discectomy and fusion (ACDF). METHODS: One hundred patients who underwent ACDF (512 intervertebral levels) were randomly selected for this radiographic review (follow-up 3-36 months). Two assessment techniques were performed by different observers, with each blinded to the results of the other. The manual spinous process displacement measurement technique was used to calculate motion between the spinous processes under magnification on a digital imaging workstation. Computer-assisted measurements of intervertebral angular motion were made using Quantitative Motion Analysis (QMA) software. Fusion criteria were arbitrarily set at 1 mm of motion for the manual technique and 1.5 degrees of angular motion for the QMA technique. RESULTS: The manual measurement technique revealed fusion in 61.7% (316 of 512) of the interspaces assessed, and QMA revealed fusion in 64.3% (329 of 512). These two assessment techniques agreed in 87.5% of cases, with a correlation coefficient of 0.68 between the two data sets. In cases in which the two techniques did not agree, QMA revealed fusion and the manual measurement revealed nonfusion in 64% of the disagreements; 98% of the disagreements occurred when motion was < 2 mm or 2 degrees. CONCLUSIONS: Although osseous fusion after arthrodesis remains difficult to assess, new computer-assisted techniques may remove the subjectivity generally associated with assessing fusion.