Positive Predicative Value Research Articles

Personal smartphones for neonatal diagnostic imaging: A prospective crossover study.

Neonatal clinicians may be asked to review X-ray images when unable to directly access the original image. Transmitting an X-ray image to a smartphone is a technique increasingly being used by clinicians in a number of settings. Minimal data exist on its use in the neonatal setting. Our aim was to compare the ability of neonatal clinicians to correctly diagnose a pneumothorax from a chest radiograph (CXR) viewed on a smartphone, paralleled with the same image viewed on a computer screen. We investigated the accuracy, sensitivity, specificity, positive predictive value and negative predicative value of two methods of viewing CXR images to diagnose pneumothorax, compared with a gold standard radiologist report. Clinicians were presented with 40 CXR images on two occasions, at least 1 week apart. Images were viewed once on a smartphone and once on a computer screen. Both the viewing method and viewing order of the images were randomised. The clinical details of the infant at the time the CXR was taken were provided, and participants were asked if a pneumothorax was present. Twenty-one clinicians viewed all CXR images using both viewing methods (840 paired observations). There was no difference in accuracy of detecting pneumothorax between viewing methods, 81% correctly identified a pneumothorax using the smartphone, versus 80% using the computer screen (P = 0.40 (95% CI), difference -4 to 1.5%). Diagnosis of neonatal pneumothorax was as accurate using a smartphone as viewing CXR images displayed on a computer screen when clinicians were presented with X-rays with diagnosis of pneumothorax.

Role of 18F-FDG PET/CT in patients with pyrexia of unknown origin

ObjectivesThis paper is a prospective observational study to assess the role of 18F-FDG PET/CT in evaluation of pyrexia of unknown origin (PUO) in a hospital based population in a tertiary level referral center in an Indian metropolitan city. Materials and methodsMedical records of 25 patients who underwent 18FDG PET/CT as a part of investigative work up of PUO were analyzed. A diagnostic CT scan was performed from the level of clavicle to the pubic symphysis in arterial and venous phases of contrast administration. Equilibrium phase images were obtained from vertex to mid-thigh without breath hold instructions with subsequent PET acquisition from vertex to mid-thigh, and these two sets of images were fused to obtain PET/CT fused images. Two radiologists with considerable PET-CT experience evaluated the contrast enhanced CT and 18-FDG PET-CT images separately and tried to identify the probable cause of fever in the 25 patients. ResultsRecords of 25 patients (13 Females, 12 Males) were evaluated. Abnormal focal FDG uptake was found in 21 patients and contributed to final diagnosis (TP) in 20 patients with 1 false positive results (FP). In the rest of the 4 patients with negative PET/CT final specific diagnosis (FN) was made only in 2 patients (2/4-50%) and in 2 patients no diagnosis was made (TN). The PET/CT had a sensitivity of 90.91%, specificity of 66.67%, positive predictive value (PPV) of 95.24% and negative predictive value (NPV-50%). TP cases included 8 cases of Kochs (2 cases of tubercular lymphadenitis, 1 case of tubercular pleural effusion, 1 case of spinal kochs, 1 case of genitourinary kochs, 1 case of Cutaneous Koch, 1 case of splenic Koch; 1 case of abdominal Koch); 4 cases of focal infections/abscesses, 1 cases of lymphoma, 2 cases of Sarcoidosis, 1 case of Kikuchi Fusimoto, 1 case of aortoarteritis, 1 case of Castleman's disease, 1 case of Rosai Dorfman and 1 case of thyroiditis. FN negative cases included one case of meningitis and one case of giant cell arteritis. One false positive case was due to focal hyper metabolism on PET in the caecum.In comparison, on CECT, probable etiology was suspected in 11 patients, out of which 8 cases were true positive (TP), 3 cases were false positive and 12 were false negative. In 2 patients no diagnosis was made (TN). CECT had a sensitivity of 42.86%, specificity of 50% positive predictive value (PPV) of 84% and negative predictive value (NPV-14.29%). Thus 18F-FDG PET/CT improved the sensitivity (90.91% vs 42.86%), specificity (66.67% vs 50%), Positive predicate value (95.24% vs 84%) and Negative predicate value (50% vs 14.29%) as compared CECT alone. ConclusionsFDG PET/CT is better than CECT in making a specific diagnosis in the evaluation of PUO. It also helps in deciding the best possible site for biopsy.

Performance of the HSV OligoGen kit for the diagnosis of herpes simplex virus type 1 and 2

PCR methods are nowadays between the most rapid and sensitive methods for screening and diagnosing herpes simplex virus (HSV) type 1 and 2. The aim of this study was to analyze the reliability, accuracy, and usefulness of the new assay HSV OligoGen kit in comparison with the Roche LightCycler HSV ½ Qual Kit assay for the detection of HSV in clinical samples. For this analysis, a prospective study was designed for detection of HSV-1 and HSV-2 including 110 ulcer specimens, 48 urine, 48 endocervical, 43 cerebral spinal fluids, 4 urethral and 3 pharyngeal swabs that were sent from a regional STI clinic or an Intensive Clinical Unit, both in Seville, Spain. In comparison to the Roche LightCycler HSV ½ Qual Kit assay, sensitivity, specificity, positive and negative predicative values, and kappa value for HSV detection using the HSV OligoGen kit were 96.2%, 100%, 100%, 98.3%, and 0.97 for HSV-1, respectively. For HSV-2, the corresponding values were 98.3%, 100%, 100%, 99.5%, and 0.98, respectively. Statistical data obtained in this study confirms the usefulness and reliable results of this new assay.

Use of bovine pregnancy-associated glycoproteins to predict late embryonic mortality in postpartum Nelore beef cows

The primary objective was to determine if circulating concentration of bovine pregnancy-associated glycoproteins (bPAGs) on Day 30 after artificial insemination (AI) may serve as a marker of late embryonic mortality in Bos indicus (Nelore) beef cows. In experiment 1, postpartum Nelore beef cows (n = 56) were artificially inseminated at a fixed time (Day 0) after synchronization of ovulation. Serum samples were collected on Days 0, 21, 24, 27, and 30 after AI. The first significant increase (P < 0.0001) in serum bPAGs after insemination occurred on Day 24 of gestation. In experiment 2, ovulation was synchronized in postpartum Nelore beef cows (n = 1460) and AI was received at a fixed time. Pregnancy diagnosis and blood sample collection were carried out on Days 28 to 30 after insemination. Cows that maintained a pregnancy from Days 28 to 100 of gestation (n = 714) had significantly (P < 0.0001) higher circulating concentrations of bPAGs on Day 28 compared with cows that did not maintain a pregnancy (embryonic mortality [EM]) until Day 100 (n = 89). When Day 28 bPAG concentration was included in a logistic regression model to predict pregnancy maintenance until Day 100 of gestation, there was an increase (P < 0.0001) in the probability of maintaining pregnancy as maternal concentrations of bPAGs increased. A receiver operating characteristic curve was generated to determine bPAG concentrations on Day 28 that should predict embryonic survival or mortality with an accuracy of 95% or more. On the basis of the positive and negative predicative value analysis, at Day 28 of gestation a circulating concentration of bPAGs greater than 7.9 ng/mL was 95% accurate in predicting embryonic maintenance (to Day 100); a concentration of bPAGs less than 0.72 ng/mL was 95% accurate in predicting EM by Day 100. In experiment 3, the preceding model was tested in a separate set of Nelore beef cows to validate whether bPAGs would serve as an accurate measure of late embryonic mortality. Ovulation was synchronized in 650 Nelore cows and received AI at a fixed time. Pregnancy diagnosis and bPAG sampling were performed at Day 28 of gestation. Only pregnant cows were included in the analysis. On the basis of the previously reported bPAG cutoff values, the test was 95% accurate in predicting late embryonic mortality at Day 28 of gestation. In summary, bPAGs seem to be a good marker for predicting EM between Days 28 and 100 of gestation and suggest that this model could help dissect the molecular mechanisms leading to late EM.

Circulating concentrations of bovine pregnancy-associated glycoproteins and late embryonic mortality in lactating dairy herds

The objectives of these experiments were as follows: (1) to determine the association between circulating concentrations of pregnancy-associated glycoproteins (PAG) and late embryonic mortality (EM) in lactating dairy cattle following fixed-time artificial insemination (TAI) on d 0 or timed embryo transfer (TET) on d 7, (2) to identify a circulating concentration of PAG on d 31 below which late EM would be likely to occur, and (3) to identify when during gestation (d 31–59) late EM is occurring. Cows were diagnosed pregnant on d 31 of gestation based on presence of a fetal heartbeat and reconfirmed to be pregnant on d 59 of gestation. Late EM occurred when a cow had a viable embryo on d 31 of gestation but not on d 59 following TAI or TET. Only pregnant cows on d 31 were included in the analysis (TAI-maintained, n=413; TAI-EM, n=77; TET-maintained, n=238; TET-EM, n=47). Cows that were pregnant at d 31 of gestation and maintained the pregnancy until d 59 had significantly higher circulating concentrations of PAG at d 31 of gestation compared with cows that experienced late EM between d 31 and 59 of gestation in both TAI and TET. To conduct a more stringent test of the effectiveness of a single circulating PAG concentration (d 31) to predict EM, a receiver-operating characteristic curve was generated to identify a PAG concentration on d 31 that would predict EM with ≥95% accuracy in cows that received TAI or TET. Based on positive and negative predicative value analysis, a circulating concentration of PAG below 1.4ng/mL (TAI; minimal detectable level 0.28ng/mL) and 1.85ng/mL (TET) was 95% accurate in predicting EM (between d 31 and 59) at d 31 of gestation, respectively. Following TET, embryonic loss was tracked by Doppler ultrasound, progesterone, and PAG from d 24 to 59 of gestation, with more than 50% of the loss occurring between d 31 and 38 of gestation. In summary, circulating concentrations of PAG on d 31 of gestation may provide a good marker for predicting EM between d 31 and 59 of gestation, and the data suggest that this model could help predict which cows will undergo late EM.

Detection of Endogenous Iron Reduction during Hepatocarcinogenesis at Susceptibility-Weighted MR Imaging: Value for Characterization of Hepatocellular Carcinoma and Dysplastic Nodule in Cirrhotic Liver.

ObjectiveTo investigate the value of susceptibility-weighted imaging (SWI) for characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN).Materials and MethodsSixty-eight cirrhotic patients with 89 hepatocellular nodules underwent SWI. The radiological features of hepatocellular nodules on SWI were classified into three types: type A (iso- or hypointensity, and background liver siderosis), type B (hyperintensity, and background liver siderosis), or type C (hyperintensity, and no background liver siderosis). Intranodular and background liver iron content was quantified and correlated with SWI pattern. Prussian blue staining was performed to quantify intranodular and background liver iron content.ResultsType A pattern (n = 12) contained 11 (91.7%) DNs and 1 (8.3%) HCC, Type B pattern (n = 66) comprised 1 (1.5%) DN and 65 (98.5%) HCCs (including 12 DN-HCCs and 53 overt HCCs), and type C pattern (n = 11) was exclusively seen in HCCs. The iron scores of DN-HCCs and overt HCCs were significantly lower than those of background livers [(0.091±0.30) VS (2.18±0.87), P = 0.000; (0.11±0.41) VS (2.16±0.97), P = 0.000; respectively]. There was no significant difference between iron scores of DNs and those of background livers [(1.92±0.29) VS (2.17±039), P = 0.191]. For lesion-based and patient-based analysis of HCCs (DN-HCCs and overt HCCs), type B pattern showed a sensitivity, specificity, accuracy, positive predicative value (PPV), and negative predicative value (NPV) of 84.4% and 84.4%, 91.7% and 75%, 85.4% and 83.8%, 98.5% and 98.2%, 47.8% and 23.1%, respectively.ConclusionSWI can provide valuable information for characterization of HCC and DN based on endogenous iron reduction during hepatocarcinogenesis.

Initial outcome of contrast-enhanced spectral mammography in lesion characterisation in the mammographically dense breast

The accuracy of mammography is limited in the dense breast. Contrast-enhanced spectral mammography (CESM) is a relatively new alternative with promising results. The aim of this study is to assess the sensitivity, specificity, positive predictive value (PPV) and negative predicative value (NPV) of CESM in the detection and characterization of breast lesions.

Methacholine challenge testing is superior to the exercise challenge for detecting asthma in children

BackgroundExercise-induced bronchoconstriction occurs in a large proportion of children with asthma. ObjectiveTo compare the predictive value of methacholine challenge testing (MCCT) and the exercise treadmill challenge (ETC) for detecting asthma in children with postexercise symptoms. MethodsThis was a prospective study of children 10 to 18 years old with postexercise symptoms. During asthma diagnosis, they underwent MCCT and ETC. There were 2 study visits. All subjects underwent ECT at visit 1 and MCCT 1 week later at visit 2. ResultsOne hundred one children were included; 62.9% had a history of atopy, and asthma was confirmed in 43.6%. MCCT showed 90.9% sensitivity, 82.5% specificity, 80.0% positive predictive value, and 92.2% negative predictive value; the respective values for ECT were 77.3%, 68.4%, 65.4%, and 79.6%. Positive MCCT results showed significantly higher sensitivity and higher positive predicative value in the diagnosis of asthma in children with postexercise symptoms compared with a 10% decrease in forced expiratory volume in 1 second for ECT (P = 0.034). Conducting MCCT during asthma diagnosis confirmed asthma in an additional 24.3% of children with exercise-induced symptoms. With a cutoff level at 17% of forced expiratory volume in 1 second for ECT, the discrepancy was decreased and reasonable values for sensitivity, specificity, positive predictive value, and negative predictive value were attained (61.0%, 77.1%, 69.4%, and 69.8%, respectively). ConclusionA large number of school children with asthma and postexercise symptoms could have positive MCCT and negative ECT findings. Untreated asthma in children with exercise-induced bronchoconstriction could cause them to be discharged from physical education classes. Trial Registrationwww.ClinicalTrials.gov, identifier NCT01798823.

Performance of the NG OligoGen kit for the diagnosis of Neisseria gonorrhoeae: comparison with cobas 4800 assay

PCR assays are nowadays between the most sensitive and reliable methods for screening and diagnosing sexually transmitted infections (STIs). The aim of this study was to analyze the reliability, accuracy, and usefulness of the new NG OligoGen kit in comparison with the cobas 4800 assay for the detection of Neisseria gonorrhoeae in clinical samples. A prospective study was designed for detection of N. gonorrhoeae including urine samples (n=152), rectal (n=80), endocervical (n=67), pharyngeal (n=41), and urethral swabs (n=5) that were sent from a regional STI clinic in Seville, Spain. Samples were collected from 255 (73.9%) men and 90 women. Sensitivity, specificity, positive and negative predicative values, and kappa value for N. gonorrhoeae detection using the NG OligoGen kit were 99.6%, 100%, 100%, 99.1%, and 0.99, respectively. Statistical data obtained in this study confirm the usefulness and reliable results of this new assay.

Higher-Resolution Magnetic Resonance Elastography in Meningiomas to Determine Intratumoral Consistency.

Magnetic resonance elastography (MRE) analyzes shear wave movement through tissue to determine stiffness. In a prior study, measurements with first-generation brain MRE techniques correlated with intraoperative observations of overall meningioma stiffness. To evaluate the diagnostic accuracy of a higher-resolution MRE technique to preoperatively detect intratumoral variations compared with surgeon assessment. Fifteen meningiomas in 14 patients underwent MRE. Tumors with regions of distinctly different stiffness were considered heterogeneous. Intratumoral portions were considered hard if there was a significant area ≥6 kPa. A 5-point scale graded intraoperative consistency. A durometer semiquantitatively measured surgical specimen hardness. Statistics included χ, sensitivity, specificity, positive and negative predicative values, and Spearman rank correlation coefficient. For MRE and surgery, 9 (60%) and 7 (47%) tumors were homogeneous, 6 (40%) and 8 (53%) tumors were heterogeneous, 6 (40%) and 10 (67%) tumors had hard portions, and 14 (93%) and 12 (80%) tumors had soft portions, respectively. MRE sensitivity, specificity, and positive and negative predictive values were as follows: for heterogeneity, 75%, 100%, 100%, and 87%; for hardness, 60%, 100%, 100%, and 56%; and for softness, 100%, 33%, 86%, and 100%. Overall, 10 tumors (67%) matched well with MRE and intraoperative consistency and correlated between intraoperative observations (P = .02) and durometer readings (P = .03). Tumor size ≤3.5 cm or vascular tumors were more likely to be inconsistent (P < .05). MRE was excellent at ruling in heterogeneity with hard portions but less effective in ruling out heterogeneity and hard portions, particularly in tumors more vascular or <3.5 cm. MRE is the first technology capable of prospectively evaluating intratumoral stiffness and, with further refinement, will likely prove useful in preoperative planning.

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Macular edema is an advance stage of diabetic retinopathy which affects central vision of diabetes patients. The main cause of edema is the appearance of exudates near or on macular region in human retina. If the exudates are present in the macular region of retina, it will lead to diabetic macular edema. Early detection of macular edema in diabetic patients paves a path for prevention from blindness. The automatic system for early detection of diabetic macular edema should identify all possible exudates present on the surface of retina. In the proposed work, a computer added diagnosis system is design for the identification of the exudates in color retinal fundus images. The system consists of three stages; candidate exudates detection, feature extraction and classification. The system is designed with (i) background estimation, morphological reconstruction, normalization for candidate exudates detection (ii) Gray level co-occurrence matrix for feature extraction and (iii) support vector machine for classification. The classifier classifies in between the region of exudates and non-exudates. The system performance is evaluated in terms of the parameters such as sensitivity, specificity, mathews correlation coefficient, positive predicative value, and accuracy whose values are 88.23%, 100%, 88.23%, 100%, 93.75% respectively.

Application of multiplex nested methylated specific PCR in early diagnosis of epithelial ovarian cancer.

To explore the application of multiplex nested methylated specific polymerase chain reaction (PCR) in the early diagnosis of epithelial ovarian carcinoma (EOC). Serum and fresh tissue samples were collected from 114 EOC patients. RUNX3, TFPI2 and OPCML served as target genes. Methylation levels of tissues were assessed by multiplex nested methylated specific PCR, the results being compared with those for carcinoma antigen 125 (CA125). The serum free deoxyribose nucleic acid (DNA) methylation spectrum of EOC patients was completely contained in the DNA spectrum of cancer tissues, providing an accurate reflection of tumor DNA methylation conditions. Serum levels of CA125 and free DNA methylation in the EOC group were evidently higher than those in benign lesion and control groups (p<0.05). Patients with early EOC had markedly lower serum CA125 than those with advanced EOC (p<0.05), but there was no significant difference in free DNA methylation (p>0.05). The sensitivity, specificity and positive predicative value (PPV) of multiplex nested methylated specific PCR were significantly higher for detection of all patients and those with early EOC than those for CA125 (p<0.05). In the detection of patients with advanced EOC, the PPV of CA125 detection was obviously lower than that of multiplex nested methylated specific PCR (p>0.05), but there was no significant difference in sensitivity (p>0.05). Serum free DNA methylation can be used as a biological marker for EOC and multiplex nested methylated specific PCR should be considered for early diagnosis since it can accurately determine tumor methylation conditions.

Comparison of the CT OligoGen kit with cobas 4800 assay for detection of Chlamydia trachomatis

IntroductionA prospective study was designed to assess the performance of the new CT OligoGen kit and the cobas 4800 assay for detection of Chlamydia trachomatis. MethodsA set of samples that included urine samples (n=212), endocervical (n=167), rectal (n=53), pharyngeal (n=7) and urethral swabs (n=3). The samples were sent from a regional sexually transmitted diseases (STD) clinic in Seville, Spain, and were collected from 261 men and 181 women. Discordant results were re-analyzed and clinical data and other tests were reviewed in order to resolve them. ResultsSensitivity, specificity, positive predicative value (PPV), negative predictive value (NPV) and kappa value for C. trachomatis detection using the CT OligoGen kit were 98.5%, 100%, 100%, 95.4% and 0.97, respectively. ConclusionsThis new kit had a high sensitivity, specificity, PPV and NPV for C. trachomatis, therefore the performance profile confirms the usefulness and reliable results of this new assay.

SUNDROP: six years of screening for retinopathy of prematurity with telemedicine

ObjectiveTo report the 6-year results of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) initiative in the context of telemedicine screening initiatives for retinopathy of prematurity (ROP). DesignA retrospective analysis. ParticipantsPremature newborns requiring ROP screening at 6 neonatal intensive care units from December 1, 2005, to November 30, 2011. MethodsInfants were evaluated via remote retinal photography by an ROP specialist. A total of 608 preterm infants meeting ROP examination criteria were screened with the RetCam II/III (Clarity Medical Systems, Pleasanton, Calif.). Primary outcomes were treatment-warranted ROP (TW-ROP) and adverse anatomical events. ResultsDuring the 6 years, 1216 total eyes were screened during 2169 examinations, generating 26 970 retinal images, an average of 3.56 examinations and 44.28 images per patient. Twenty-two (3.6%) of the infants screened met criteria for TW-ROP. Compared with bedside binocular ophthalmoscopy, remote interpretation of RetCam II/III images had a sensitivity of 100%, specificity of 99.8%, positive predicative value of 95.5%, and negative predicative value of 100% for the detection of TW-ROP. No adverse anatomical outcomes were observed for any enrolled patient. ConclusionsThe 6-year results for the SUNDROP telemedicine initiative were highly favourable with respect to diagnostic accuracy. Telemedicine appears to be a safe, reliable, and cost-effective complement to the efforts of ROP specialists, capable of increasing patient access to screening and focusing the resources of the current ophthalmic community on infants with potentially vision-threatening disease.

Biometric Parameters in Different Stages of Primary Angle Closure Using Low-Coherence Interferometry

To compare ocular biometric parameters using low-coherence interferometry among siblings affected with different degrees of primary angle closure (PAC). In this cross-sectional comparative study, a total of 170 eyes of 86 siblings from 47 families underwent low-coherence interferometry (LenStar 900; Haag-Streit, Koeniz, Switzerland) to determine central corneal thickness, anterior chamber depth (ACD), aqueous depth (AD), lens thickness (LT), vitreous depth, and axial length (AL). Regression coefficients were applied to show the trend of the measured variables in different stages of angle closure. To evaluate the discriminative power of the parameters, receiver operating characteristic curves were used. Best cutoff points were selected based on the Youden index. Sensitivity, specificity, positive and negative predicative values, positive and negative likelihood ratios, and diagnostic accuracy were determined for each variable. All biometric parameters changed significantly from normal eyes to PAC suspects, PAC, and PAC glaucoma; there was a significant stepwise decrease in central corneal thickness, ACD, AD, vitreous depth, and AL, and an increase in LT and LT/AL. Anterior chamber depth and AD had the best diagnostic power for detecting angle closure; best levels of sensitivity and specificity were obtained with cutoff values of 3.11 mm for ACD and 2.57 mm for AD. Biometric parameters measured by low-coherence interferometry demonstrated a significant and stepwise change among eyes affected with various degrees of angle closure. Although the current classification scheme for angle closure is based on anatomical features, it has excellent correlation with biometric parameters.

Accuracy of Diagnosing PDA, Neuroendocrine Tumors, and IPMN by EUS-FNA at a Single Institution

Background: The purpose of this study was to assess the clinical impact of diagnostic accuracy for EUS-FNA in evaluating pancreatic lesions, particularly Pancreatic Ductal Adenocarcinoma( PDAC), neuroendocrine tumors, and IPMN at our institution using surgical pathological review as the gold standard. Methods: We conducted a retrospective chart review using the Clinical Cancer Research Database at Huntsman Cancer Institute. We included all cases in which pancreatic lesions were evaluated by EUS-FNA and a subsequent surgical resection was performed. Sensitivity, specificity, positive predicative value (PPV), and negative predictive value (NPV) were determined for PDAC, neuroendocrine tumors, and IPMN by comparing pathological diagnosis at EUS-FNA to diagnoses following surgery. Results: Detection of PDAC by FNA-EUS yielded 87.9% (80.1-93.4 95% CI) sensitivity, 80% (72-86) specificity, 78% (70-85) PPV, and 89% (82-94) NPV. Detection of neuroendocrine tumors by FNA-EUS yielded 66% (47-87) sensitivity, 100% (97-100) specificity, 94% (71-99) PPV, and 97% (94-99) NPV. Detection of IPMN by FNA-EUS yielded 59% (43-74) sensitivity, 100% (98-100) specificity, 100% (87-100) PPV, and 89% (93-99) NPV. Conclusions: Our findings are largely consistent with the current literature, confirming there is discernible potential for inappropriate treatment of patients based purely on EUS-FNA evaluation. Both accuracy and clarity of positive tests with EUS-FNA worsened for mucinous pancreatic lesions compared to solid pancreatic lesions. Limitations of this study are the appraisal at a single institution and the necessity to evaluate only cases that ultimately had surgical resection of the pancreatic lesion.

Automated 3-D retinal layer segmentation of macular optical coherence tomography images with serous pigment epithelial detachments.

Automated retinal layer segmentation of optical coherence tomography (OCT) images has been successful for normal eyes but becomes challenging for eyes with retinal diseases if the retinal morphology experiences critical changes. We propose a method to automatically segment the retinal layers in 3-D OCT data with serous retinal pigment epithelial detachments (PED), which is a prominent feature of many chorioretinal disease processes. The proposed framework consists of the following steps: fast denoising and B-scan alignment, multi-resolution graph search based surface detection, PED region detection and surface correction above the PED region. The proposed technique was evaluated on a dataset with OCT images from 20 subjects diagnosed with PED. The experimental results showed the following. 1) The overall mean unsigned border positioning error for layer segmentation is 7.87±3.36 μm , and is comparable to the mean inter-observer variability ( 7.81±2.56 μm). 2) The true positive volume fraction (TPVF), false positive volume fraction (FPVF) and positive predicative value (PPV) for PED volume segmentation are 87.1%, 0.37%, and 81.2%, respectively. 3) The average running time is 220 s for OCT data of 512 × 64 × 480 voxels.

Multi-fingered haptic palpation utilizing granular jamming stiffness feedback actuators

This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and in robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback.

Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in an STI population: performances of the Presto CT-NG assay, the Lightmix Kit 480 HT CT/NG and the COBAS Amplicor with urine specimens and urethral/cervicovaginal samples

ObjectivesThis study assessed the performances of the Presto CT-NG assay, the Lightmix Kit 480 HT CT/NG and the COBAS Amplicor for Chlamydia trachomatis and Neisseria gonorrhoeae detection.DesignA cross-sectional study design.SettingIzore,...

An administrative data algorithm to identify traumatic spinal cord injured patients: a validation study

To assess the validity of different administrative data sources available for the identification of traumatic spinal cord injured (TSCI) patients. Retrospective validation study. Ontario, Canada. Adult patients seen in tertiary outpatient spinal cord rehabilitation clinics after 1 April 2002. Sensitivity, specificity, positive and negative predicative values of diagnostic ICD10 codes from Canadian Institutes of Health Discharge Abstracts (CIHI-DAD), Rehabilitation Coding Groups (RCG) from that National Rehabilitation System (NRS), and spinal cord injury fee codes from the Ontario Healthcare Insurance Plan (OHIP). Secondary outcome was the agreement between actual lesion level and RCG/ICD10 coded lesion level. The RCG codes in the NRS have high sensitivity (92%, 95% confidence interval (CI): 87-95%) and specificity (97%, 95% CI: 94-99%) for the identification of true TSCI patients, whereas CIHI-DAD ICD10 codes are highly specific (99%, 95% CI: 95-100) and moderately sensitive (76%, 95% CI: 79-87%). OHIP fee codes had poor sensitivity (64%, 95% CI: 57-71%). Agreement between true lesion level and the NRS and CIHI-DAD coding is good (Kappa of 0.65-0.88 and 0.56-0.70, respectively). This study demonstrated that the NRS is able to accurately discriminate between patients with and without a TSCI. A large population of incident and prevalent TSCI patients are identifiable using administrative data. This study was funded by a grant from the Division of Urology, Western University.