scholarly journals Application of a scheimpflug-based biomechanical analyser and tomography in the early detection of subclinical keratoconus in chinese patients

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yan Liu ◽  
Yu Zhang ◽  
Yueguo Chen

Abstract Background In vivo corneal biomechanics evaluation has been used to help screen early keratoconus in recent years. This study is to evaluate the value of a Scheimpflug-based biomechanical analyser combined with tomography in detecting subclinical keratoconus by distinguishing normal eyes from frank keratoconus (KC) and forme frusta keratoconus (FFKC) eyes in Chinese patients. Methods Study design: diagnostic test. This study included 31 bilateral frank keratoconus patients, 27 unilateral clinically manifesting keratoconus patients with very asymmetric eyes, and 79 control subjects with normal corneas. Corneal morphological and biomechanical parameters were measured using a Pentacam HR and a Corvis ST (OCULUS, Wetzlar, Germany). The diagnostic ability of computed parameters reflecting corneal biomechanical and morphological traits [including the Belin-Ambrósio deviation index (BAD_D), the Corvis biomechanical index (CBI) and the tomographic and biomechanical index (TBI)] was determined using receiver operating characteristic (ROC) curve analysis and compared by the DeLong test. Additionally, the area under the curve (AUC), the best cut-off values, and the Youden index for each parameter were reported. A novel corneal stiffness parameter, the stress-strain index (SSI), was also compared between KC, FFKC and normal eyes. Results Every morphological and biomechanical index analysed in this study was significantly different among KC, FFKC and normal eyes (P = 0.000). The TBI was most valuable in detecting subclinical keratoconus (FFKC eyes), with an AUC of 0.928 (P = 0.000), and both forms of corneal ectasia (FFKC and frank KC eyes), with an AUC of 0.966 (P = 0.000). The sensitivity and specificity of the TBI was 97.5 and 77.8 % in detecting FFKC and 97.5 and 89.7 % in detecting any KC, respectively, with a cut-off value of 0.375. The morphological index BAD_D and the biomechanical index CBI were also very useful in distinguishing eyes with any KC from normal eyes, with AUCs of 0.965 and 0.934, respectively. The SSI was significantly different between KC, FFKC and normal eyes (P = 0.000), indicating an independent decrease in corneal stiffness in KC eyes. Conclusions The combination of a Scheimpflug-based biomechanical analyser and tomography could increase the accuracy in detecting subclinical keratoconus in Chinese patients. The TBI was the most valuable index for detecting subclinical keratoconus, with a high sensitivity and specificity. Evaluation of corneal biomechanical properties in refractive surgery candidates could be helpful for recognizing potential keratoconic eyes and increasing surgical safety.

2020 ◽  
Author(s):  
Yan Liu ◽  
Yu Zhang ◽  
Yue-guo Chen

Abstract PurposeTo evaluate the value of Scheimpflug-based biomechanical analyzer combined with tomography in detecting early keratoconus by distinguishing normal eyes from frank keratoconus (KC) and forme frusta keratoconus (FFKC) eyes in Chinese patients. MethodsThis study included 31 bilateral frank keratoconus patients, 27 unilateral clinical manifest keratoconus patients with very asymmetric eyes, and 79 control subjects with normal corneas. Corneal morphological and biomechanical parameters were measured using the Pentacam HR and Corvis ST (OCULUS, Wetzlar, Germany). The diagnostic capacity of computed parameters reflecting corneal biomechanical and morphological traits [including Belin-Ambrósio deviation index (BAD_D), Corvis biomechanical index (CBI) and tomographic and biomechanical index (TBI)] was determined using receiver operating characteristic (ROC) curves and compared by DeLong test. Additionally, the area under the curve (AUC), the best cutoff values, and Youden index for each parameter were reported. The novel corneal stiffness parameter (Stress-Strain Index or SSI) was also compared between KC, FFKC and normal eyes.ResultsEvery morphological and biomechanical index analyzed in this study was significantly different between KC, FFKC and normal eyes (p=0.000). TBI was most valuable for detecting subclinical keratoconus (FFKC eyes) with an AUC of 0.928 (P=0.000), and any forms of corneal ectasia (FFKC and frank KC eyes) with an AUC of 0.966 (P=0.000). The sensitivity and specificity of TBI for detecting FFKC was 97.5% and 77.8%, for detecting any KC was 97.5% and 89.7%, with a cut-off value of 0.375. Morphological index BAD_D and biomechanical index CBI were also very useful in distinguishing any KC eyes from normal eyes with an AUC of 0.965 and 0.934, respectively. SSI was significantly different between KC, FFKC and normal eyes (P=0.000), indicating an independent decrease in corneal stiffness in KC eyes.Conclusion Combination of Scheimpflug-based biomechanical analyzer and tomography could increase the accuracy of detecting early keratoconus in Chinese patients. TBI was the most valuable index for detecting subclinical keratoconus with high sensitivity and specificity. Evaluation of corneal biomechanical property in refractive surgery candidates is helpful to recognize potential keratoconic eyes and increase surgical safety.


2020 ◽  
Author(s):  
Jose M Garcia ◽  
Beverly M. K. Biller ◽  
Marta Korbonits ◽  
Vera Popovic ◽  
Anton Luger ◽  
...  

Objective: The macimorelin test is approved for the diagnosis of adult growth hormone deficiency (AGHD) based on its efficacy vs the insulin tolerance test (ITT). Macimorelin has a significant advantage over ITT in avoiding hypoglycemia. Analyses were conducted to determine whether macimorelin performance is affected by age, body mass index (BMI), or sex, and evaluate its performance vs ITT over a range of GH cutpoints. Design: Post hoc analyses of data from a previous randomized phase 3 study included participants aged 18-66 years with BMI <37 kg/m2 and high (Group A), intermediate (Group B), or low (Group C) likelihood for AGHD based on pituitary history, and matched controls (Group D). Methods: Probability of AGHD was estimated using unadjusted, age-adjusted, BMI-adjusted, and sex-adjusted logistic models. Area under the curve (AUC) of the estimated receiver operating characteristic (ROC) curve (range, 0-1; 1=perfect) was compared for adjusted vs unadjusted models. Separate analyses evaluated agreement, sensitivity, and specificity for macimorelin and ITT using cutpoints of 2.8, 4.0, 5.1, and 6.5 ng/mL. Results: For participants in Group A (n=41) and Group D (n=29), unadjusted, age-adjusted, BMI-adjusted, and sex-adjusted models had ROC AUCs (95% CIs) of 0.9924 (0.9807-1), 0.9924 (0.9807-1), 0.9916 (0.9786-1), and 0.9950 (0.9861-1), respectively. Conclusions: Macimorelin performance was not meaningfully affected by age, BMI, or sex, indicating robustness for AGHD diagnosis. Of the 4 GH cutpoints evaluated, the cutpoint of 5.1 ng/mL provided maximal specificity (96%) and high sensitivity (92%) and was in good overall agreement with the ITT at the same cutpoint (87%).


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Liam McGuirk ◽  
Tara P Patale ◽  
Nicholas Andrew Krasnow ◽  
Alice Alexandrov ◽  
James Haigney ◽  
...  

Abstract Background: It is speculated that pituitary volume (PV) is a marker of chronic growth hormone (GH) secretion. In previous studies, we determined that children with GH deficiency (GHD) and idiopathic short stature (ISS) had significantly smaller PVs than normal controls (NCs). Cutoff values for small PVs are needed to improve the clinical utility of PV in determining children who qualify for GH therapy. Objective: To define the cutoff between pathologic and nonpathologic PV in prepubertal and pubertal children with short stature (SS). Patients and Methods: The SS group was selected from the database of a pediatric endocrinology center, which was queried for siblings (SBs) aged 6–18 yrs who underwent a GH stimulation test and MRI between 2013–2019. All 77 SBs had SS, defined as 2 SDs below mean height for age, subnormal growth velocity for at least 6 months, or predicted height at least 2 inches discrepant from midparental height. The NC group was selected from the database of a neuroradiology center; these NCs consisted of 170 randomly selected subjects aged 6–18 yrs. Patients with MRI abnormalities were excluded. PVs were calculated using the ellipsoid formula (LxWxH/2). ROC curve analysis was utilized to generate cutoff values. The diagnosis of short stature was the dependent variable and PV was the independent variable. The PV with the highest Youden index was selected as the definitive cutoff for a small PV. Results: The mean (MN) and median (MD) age of SBs was 11.6 ±2.2 and 11.9 yrs, respectively, and the MN and MD age of the NCs was 12.6 ±3.4 and 13.2 yrs, respectively. The MN and MD age of prepubertal SBs (n=29) and NCs (n=58) were 9.3 ±1.2 and 9.7, and 8.6 ±1.4 and 8.6 yrs, respectively. The MN and MD age of pubertal SBs (n=48) and NCs (n=112) were 13.0 ±1.4 and 12.7, and 14.7 ±1.9 and 14.6 yrs, respectively. The difference in MN age between SBs and NCs was significant (p&lt;0.05). For prepubertal subjects, sensitivity was 86.21% and specificity was 68.97%. The distance to corner was 0.3396, and the highest Youden index was 0.5517, corresponding to a PV of 215.02 mm3. The Area Under the Curve (AUC) was 0.8395 with a standard error of 0.0426 (p&lt;0.001). For pubertal subjects, sensitivity was 81.25% and specificity was 79.46%. The distance to corner was 0.2781, and the highest Youden index was 0.6071, corresponding to a PV of 315.0 mm3. The AUC was 0.8460 with a standard error of 0.0337 (p&lt;0.001). Conclusion: To our knowledge, we present the first study on the sensitivity and specificity of PV in determining the etiology of SS. Our data suggest that prepubertal patients with a PV&lt;215.02 mm3 and pubertal patients with a PV&lt;315.00 mm3 have small pituitary glands. Statistically calculated cutoffs are necessary to accurately diagnose pituitary hypoplasia and should be utilized to determine the etiology of SS. Future studies should include children with Tanner staging and height SDs to generate more accurate PV cutoffs.


2020 ◽  
Author(s):  
Yuri Kiso ◽  
Yoko Matsuda ◽  
Shikine Esaka ◽  
Yuri Hamashima ◽  
Hiroto Shirahata ◽  
...  

Abstract Background: Cytological diagnosis of pancreatic specimens obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is often challenging because of the small amount of sample or well-differentiated adenocarcinoma with weak cytological atypia. Therefore, the sensitivity and specificity of cytological diagnosis for pancreatic cancer should be improved. Hence, we aimed to evaluate the indices, which are used to distinguish malignant from benign lesions for the cytological diagnosis of pancreatic EUS-FNA specimens. Methods: Seven reviewers, including 3 cytotechnologists and 4 medical doctors, evaluated 20 morphological indices in pancreatic specimens obtained by EUS-FNA (malignant, n=111; benign, n=31). Statistical analyses were performed using Fisher’s exact test, logistic regression analysis, area under the receiver operating characteristic curve, and Youden Index.Results: Among the 20 indices, there was a high incidence rate (>40%) of the following 13 indices in malignant cases: structural atypia, hyperchromatic nucleus, irregular cell polarity, unclear cell boundary, nuclear membrane thickening, anisonucleosis, overlapping, irregular nuclei, high nuclear/cytoplasmic ratio, binding decline, simultaneous appearance of malignant and benign cells, enlarged nucleoli, and background necrosis. When we diagnosed pancreatic specimens using these 13 cytological indices, the cutoff value of 8/9 showed the highest Youden index (0.950) as well as high sensitivity and specificity in distinguishing malignant from benign specimens (98% and 97%, respectively). Conclusion: Thirteen cytological indices showed high sensitivity and specificity in differentiating malignant and benign lesions using pancreatic EUS-FNA samples. Further validation or prospective studies are necessary to establish criteria for the cytological diagnosis of pancreatic cancer.


2021 ◽  
Author(s):  
Shubin Li ◽  
Yang Gao ◽  
Mingqiu Hu ◽  
Yuehuan Li ◽  
Xu Meng

Abstract Background:This study aimed to evaluate the role of SAMe-TT2R2 score in the prediction of anticoagulation control after mechanical mitral valve replacement.Methods and Results:We retrospectively reviewed clinical data of 161 patients who received mechanical mitral valve replacement at Beijing Anzhen Hospital from January 2013 to December 2013. Collected data included general information of patients, medication and smoking, postoperative embolism due to anticoagulant, bleeding complications and death information. In the SAMe-TT2R2 score results, the lowest score was 2 points (6.3%), the highest score was 7 points (0.7%). The number of people with 4 points was the largest ,60 people (41.4%).When the cut-off value of SAMe-TT2R2 score was set to ≥4, the sensitivity and specificity of predicting TTR≥65% were 69.8% and 93.1%, respectively. The Youden index was 0.629. If the cut-off value of SAMe-TT2R2 score was set to ≤4, the sensitivity and specificity of predicting TTR≥65% were 93.0% and 44.1%, respectively, and the Youden index was 0.371.ROC curve evaluates the predictive power of the SAMe-TT2R2 score for TTR≥65%. The figure showed that when the cut-off point≥4, the best combination of sensitivity and specificity was shown (69.8% and 93.1%, respectively).The area under the curve AUC was 0.854.Conclusions:After mechanical mitral valve replacement, the SAME-TT2R2 model can effectively predict the level of TTR during the course of using oral warfarin anticoagulation, and the SAMe-TT2R2 score ≥4 can be used to predict TTR<65%.


2020 ◽  
Author(s):  
jingxian Wang ◽  
Peiyan Zheng ◽  
Zhifeng Huang ◽  
Huimin Huang ◽  
Mingshan Xue ◽  
...  

Abstract Background: Some patients with interstitial pneumonia with autoimmune features (IPAF) showed a progressive course despite therapy. This study aimed to evaluate whether serial changes in the serum levels of surfactant protein-A (SP-A) and Krebs von den Lungen-6 (KL-6) can predict disease progression. Methods: Sixty-four patients with IPAF and 41 patients with non-fibrotic lung disease (non-FLD) were examined. Based on long-term changes in lung function, 36 IPAF patients who were followed up for more than 3 months were divided into a progressive group (n=9), an improvement group (n=13), and a stable group (n=14). Serum KL-6 and SP-A levels were measured. The sensitivity, specificity, cut-off value, and area under the curve (AUC) value for each of the indices were determined using receiver operating characteristic (ROC) curve analysis. The expression differences in these biomarkers and their correlation with disease severity were analyzed. Results: Compared with non-FLD patients, serum SP-A and KL-6 levels in IPAF patients were increased significantly [SP-A: (p < 0.001); KL-6: (p < 0.001)] and negatively correlated with DLCO (SP-A: rS = -0.323, p = 0.018; KL-6: rS = -0.348, p = 0.0011). In patients with progressive disease, the posttreatment serum SP-A and KL-6 levels were increased significantly compared with pretreatment levels [SP-A: (p = 0.021); KL-6: (p = 0.008)]. In patients showing improvement, the levels were decreased significantly [SP-A (p = 0.007) and KL-6 (p = 0.002)]. Changes in serum biomarkers (Delta SP-A and Delta KL-6) were significantly negatively correlated with changes in lung function (Delta FVC, Delta DLCO and Delta FEV1) (rS = 0.482, p < 0.05). A significant positive correlation was found between Delta SP-A and Delta KL-6 (rS = 0.482, p < 0.001). Conclusions: Serum SP-A and KL-6 offer high sensitivity and specificity for the diagnosis of IPAF. The decrease in serum SP-A and/or KL-6 levels in patients with IPAF is related to the improvement in pulmonary function. SP-A and KL-6 may be important biomarkers for predicting disease progression in patients with IPAF.


Author(s):  
Vefa Cakmak ◽  
Duygu Herek ◽  
Pinar Cakmak

Background: During the COVID-19 pandemic, the workload of all radiologists and radiology residents, as well as other clinical physicians, has increased. Introduction: This study aims to determine the diagnostic performance of radiology residents, who effectively contribute to the diagnosis of COVID-19. Methods: The thoracic computed tomography (CT) images of 135 patients aged 20–83 diagnosed with COVID-19 were evaluated retrospectively by five radiology residents and a radiologist with 10 years of experience. The diagnostic performance of the radiology residents in evaluating COVID-19 was assessed according to their year of residency and the patients’ age and gender. Receiver operating characteristic (ROC) curve analysis was performed to determine the sensitivity and specificity of radiology residents. Results: The radiology residents’ performance in determining COVID-19 using CT findings was evaluated as follows: sensitivity 97.22%, specificity 88.89%, positive predictive value 90.91%, negative predictive value 96.55%, and accuracy 93.33%. According to the year of residency, the sensitivity and specificity of the radiology residents in determining COVID-19 using CT images were between 92.3% and 100%, and 71.43% and 100%, respectively. Conclusion: The high sensitivity and specificity of radiology residents in evaluating thoracic CT images for COVID-19 diagnosis indicate that radiologists are as important as clinical physicians in the diagnosis of COVID-19.


2020 ◽  
Vol 7 (4) ◽  
pp. e775 ◽  
Author(s):  
Frida Duell ◽  
Björn Evertsson ◽  
Faiez Al Nimer ◽  
Åsa Sandin ◽  
Daniel Olsson ◽  
...  

ObjectiveTo determine what kappa free light chain (KFLC) metric has the highest capacity to separate healthy patients from patients with MS, we evaluated the sensitivity, specificity, and the overall diagnostic accuracy of 4 different KFLC metrics. To assess the usefulness of KFLC in the diagnostics of MS, we compared the different KFLC metrics with oligoclonal bands (OCBs), the current gold standard biochemical method to demonstrate intrathecal antibody production.MethodsCSF and plasma were collected from patients with confirmed or suspected MS, other neurological diseases, as well as symptomatic and healthy controls between May 2017 and May 2018 (n = 335) at the Department of Neurology, Karolinska University Hospital, as part of routine diagnostic workup. KFLC analysis and isoelectric focusing for the detection of oligoclonal bands (OCB) were determined and correlated with diagnosis. Receiver operating characteristic (ROC) curve analysis was used to determine accuracy.ResultsOCBs yielded a sensitivity of 87% and a specificity of 100%. All KFLC metrics showed a high sensitivity (89%–95%) and specificity (95%–100%). Using the optimal cutoff according to the Youden Index resulted for the KFLC intrathecal fraction in a cutoff of −0.41 with a sensitivity of 95% and a specificity of 97% and for CSF KFLC/CSF albumin with a cutoff of 1.93 × 10−3 with a sensitivity of 94% and specificity of 100%.ConclusionAll evaluated KFLC metrics have excellent accuracy, and both KFLC intrathecal fraction and CSF KFLC/CSF albumin are at least as good as OCB in separating patients with MS from a control group.Classification of evidenceThis study provides Class III evidence that CSF KFLC accurately distinguishes patients with MS from healthy controls.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jingxian Wang ◽  
Peiyan Zheng ◽  
Zhifeng Huang ◽  
Huimin Huang ◽  
Mingshan Xue ◽  
...  

Abstract Background Some patients with interstitial pneumonia with autoimmune features (IPAF) showed a progressive course despite therapy. This study aimed to evaluate whether serial changes in the serum levels of surfactant protein-A (SP-A) and Krebs von den Lungen-6 (KL-6) can predict disease progression. Methods Sixty-four patients with IPAF and 41 patients with non-fibrotic lung disease (non-FLD) were examined. Based on long-term changes in lung function, 36 IPAF patients who were followed up for more than 3 months were divided into a progressive group (n = 9), an improvement group (n = 13), and a stable group (n = 14). Serum KL-6 and SP-A levels were measured. The sensitivity, specificity, cut-off value, and area under the curve (AUC) value for each of the indices were determined using receiver operating characteristic (ROC) curve analysis. The expression differences in these biomarkers and their correlation with disease severity were analyzed. Results Compared with non-FLD patients, serum SP-A and KL-6 levels in IPAF patients were increased significantly [SP-A: (p < 0.001); KL-6: (p < 0.001)] and negatively correlated with DLCO (SP-A: rS = − 0.323, p = 0.018; KL-6: rS = − 0.348, p = 0.0011). In patients with progressive disease, the posttreatment serum SP-A and KL-6 levels were increased significantly compared with pretreatment levels [SP-A: (p = 0.021); KL-6: (p = 0.008)]. In patients showing improvement, the levels were decreased significantly [SP-A (p = 0.007) and KL-6 (p = 0.002)]. Changes in serum biomarkers (Delta SP-A and Delta KL-6) were significantly negatively correlated with changes in lung function (Delta FVC, Delta DLCO and Delta FEV1) (rS = 0.482, p < 0.05). A significant positive correlation was found between Delta SP-A and Delta KL-6 (rS = 0.482, p < 0.001). Conclusions Serum SP-A and KL-6 offer high sensitivity and specificity for the diagnosis of IPAF. The decrease in serum SP-A and/or KL-6 levels in patients with IPAF is related to the improvement in pulmonary function. SP-A and KL-6 may be important biomarkers for predicting disease progression in patients with IPAF.


2013 ◽  
Vol 36 (2) ◽  
pp. 81 ◽  
Author(s):  
Jinpeng Zhong ◽  
Yonghong Wang ◽  
Xiaoling Wang ◽  
Fengzeng Li ◽  
Yulei Hou ◽  
...  

Purpose: The purpose of this study is to evaluate the ability of cardio-ankle vascular index (CAVI), high-sensitivity C-reactive protein (hs-CRP) levels and homocysteine (Hcy) levels to screen for subclinical arteriosclerosis (subAs) in an apparently healthy population, with the view to obtaining an optimal diagnostic marker or profile for subAs. Methods: Subjects (152) undergoing routine health examinations were recruited and divided into two groups: carotid arteriosclerosis (CA) and non-carotid arteriosclerosis (NCA), according to carotid intima-media thickness (CMIT). CAVI was calculated based on blood pressure and pulse wave velocity. Serum hs-CRP and Hcy levels were also measured. A Receiver Operating Characteristic (ROC) curve was plotted to evaluate the efficacy of each in carotid arteriosclerosis screening. Ten parameter combinations, designated W1 to W10, were compared in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Results: The levels of all three parameters were significantly higher in the CA group, compared with the NCA group. ROC curves showed that the area under the curve (AUC) for CAVI was 0.708 (95%CI: 0.615-0.800), which is significantly larger than that of either hs-CRP (0.622) or Hcy (0.630), respectively (P < 0.001). Maximum sensitivity (100%) and NPV (100%) were attained with W10, while maximum specificity (86.2%) and PPV (46.7%) were obtained with W7. With W9, the maximum Youden index (0.416) was obtained, with a sensitivity of 77.8% and specificity of 63.8%. Conclusions: CAVI is more effective than hs-CRP or Hcy for subAs screening. The optimal profile was obtained with a combination of CAVI and other parameters.


Sign in / Sign up

Export Citation Format

Share Document