• Title/Summary/Keyword: Negative Predictive Value (NPV)

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Prevalence-based Interpretation of Predictive Values of Diagnostic Tests: An Example for Detection of Canine Heartworm Infection (진단키트 검사결과에 대한 유병율 위주 해석: 개 심장사상충의 예)

  • Park, Choi-Kyu;Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.26 no.2
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    • pp.130-133
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    • 2009
  • The use of screening tests as part of a diagnostic work-up is common in domestic canine practice, but understanding of the diagnostic test characteristics and factors affecting diagnostic accuracy is not clear among clinicians. This article was aimed to provide clinicians with a better understanding on the selection of test kits and with a proper interpretation of test results using an example from heartworm(Dirofilaria immitis) studies. From the literatures, diagnostic accuracy varied depending on the kits: percent average sensitivity and specificity of ELISA antigen-detecting kits were DiroChek(Synbiotics, USA) 78.1 and 95.2, SNAP(IDEXX, USA) 66.3 and 98.1, and Solo Step(Heska, Switzerland) 69.5 and 97.5, respectively, while the values for three hematological methods(Modified Knott's, direct smear and capillary tube) ranged from 38.4 to 81.8% and from 96.9 to 100%, respectively. Furthermore, it was also reported that the prevalence of heartworm disease in domestic dog populations varied depending on the regions studied: 2.5-22.8% for microfilarial test and 2.2-66.3% by ELISA. The values of predictive values for positive(PPV) and negative(NPV) provide useful information to clinicians on the probability of heartworm infection, but the PPV and NPV are greatly dependent on the heartworm prevalence. This suggests that PPV or NPV values of a test should be interpreted carefully in different clinical settings. Practical methods on the interpretation taking into account heartworm prevalence were discussed.

The Role of Single-contrast CT for Management in Hemodynamically Stable Anterior Abdominal Stab wound Patients (혈역학적으로 안정된 복부 전벽 자상 환자의 개복 수술 결정에서 Single-contrast CT의 역할)

  • Jo, Janghwan;Kim, Joongsuck;Kim, Yeongcheol;Chung, Ilyong;Park, Jongmin;Ahn, Eunjung;Kim, Eunyoung;Park, Seihyeog;Kim, Seongyup
    • Journal of Trauma and Injury
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    • v.27 no.4
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    • pp.145-150
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    • 2014
  • Purpose: To assess the accuracy and role of single-contrast computed tomography (CT) in the management of anterior abdominal stab wound (AASW). Methods: During 8-years period, single-contrast CT was performed in 21 hemodynamically stable AASW patients (age range, 22-64 years; median age, 45 years), including 19 men and 2 women. CT scans were evaluated by one trauma surgeon and one senior resident to determine the depth of injury(peritoneal violation or not), and abnormal findings of intraperitoneal cavity associated with stab injury. We retrospectively reviewed medical records regarding operative findings. Results: Nine patients underwent abdominal surgery and 12 patients nonoperative management. In the abdominal surgery group, abnormal CT findings included peritoneal violation in 14 patients and abnormal intraperitoneal cavity findings in 5 patients. There was no statistical significant difference regarding abnormal CT findings between abdominal surgery group and nonoperative management group. Among the nine abdominal surgery patients, therapeutic laparotomy was performed on 4 patients. The positive predictive value (PPV) and negative predictive value (NPV) of peritoneal violation to predictive therapeutic laparotomy were 28.6% and 100%, respectively. In addition, the PPV and NPV of abnormal intraperitoneal cavity CT findings to predict therapeutic laparotomy were 40.0% and 87.5%, respectively. There was no statistical significant difference regarding the abnormal CT findings between therapeutic laparotomy group and non therapeutic laparotomy group. Conclusion: CT is a good adjunctive method to evaluate hemodynamicaly stable AASW patients. If peritoneal violation is not seen on CT scan, conservative treatment on local wound may be safely performed without additional abdominal surgery. However, further study is warranted to evaluate the exact role of CT in the diagnostic workup of AASW patients.

Incidental Finding of Abnormal Cervical Pathology in Hysterectomy Specimens after Normal Preoperative Papanicolaou Smears in Thammasat University Hospital

  • Chundarat, Pong-Anan;Suwannarurk, Komsun;Bhamarapravatana, Kornkarn;Pattaraarchachai, Junya;Thaweekul, Yuthadej;Mairaing, Karicha;Poomtavorn, Yenrudee
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5811-5814
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    • 2014
  • Background: To investigate abnormal cervical histopathology (ACH) from hysterectomy specimens with normal preoperative Papanicolaou (Pap) smears. Materials and Methods: Medical records from May 2009 to April 2012 were retrospectively reviewed of subjects from whom hysterectomy specimens were taken in Thammasat University Hospital. All had normal preoperative Pap smears. ACH was the primary outcome. A p-value less than 0.05 was considered significant. A total of 483 subjects with an average age of 50.5 years were recruited. Benign cases of enlarged uterus and pelvic mass were present in 94% (430/483). Endometrial and ovarian cancer were found at 6.2 and 4.7%, respectively. In hysterectomy specimens there were 19 (4%) cases of ACH. Silent ACH with benign disease, endometrial and ovarian cancers were 1.2% (5/430), 33.3% (10/30) and 17.4% (4/23), respectively. The negative predictive value (NPV) and false negative rate of Pap smears were 96 and 4%, respectively. ACH in malignant cases were 27.9% (12/43) and 20% (2/10) in adequate (APS) and inadequate (IPS) Pap collection groups, respectively. ACH in benign condition were 0.68% (2/292) and 2.2% (3/138) in APS and IPS, respectively. ACH was more often found in hysterectomy specimens with indication of malignancy than benign conditions with statistical significance. One third of preoperative stage I endometrial cancer cases had cervical involvement. Conclusions: Silent ACH in normal preoperative Pap smear was 4 %. Inadequate Pap smear collection is still the major problem in this study. Reducing inadequate Pap smear collection could reduce the false negative rate.

Serum Beta-2 Microglobulin: a Possible Marker for Disease Progression in Egyptian Patients with Chronic HCV Related Liver Diseases

  • Ouda, SM;Khairy, AM;Sorour, Ashraf E;Mikhail, Mikhail Nasr
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7825-7829
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    • 2015
  • Background: Egypt has the highest prevalence of HCV infection in the world (~14.7%). Around 10-15% of HCV-infected persons will advance to cirrhosis within the first 20 years. The incidence of HCC is expected to grow in the next two decades, largely due to HCV related cirrhosis, and detection of HCC at an early stage is critical for a favorable clinical outcome. No simple reliable non-invasive marker has been available till now. B2M, a non-glycosylated polypeptide composed of 99 amino acids, is one of the components of HLA class I molecules on the surfaces of all nucleated cells. It has been reported that the level of serum B2M is elevated in patients with chronic hepatitis C and HCV-related HCC when compared to HCV-negative patients or healthy donors. Determining the clinical utility of serum B2M as a marker for disease progression in Egyptian patients with HCV related chronic hepatitis, cirrhosis and hepatocellular carcinoma was the aim of the present study. Materials and Methods: In this analytical cross sectional study 92 participants were included in 4 equal groups: Group (1) non cirrhotic chronic HCV; Group (2) HCV related liver cirrhosis; Group (3) HCC on top of HCV,; and Group (4) healthy controls. History taking, clinical examination, routine labs and abdominal ultrasound were conducted for all patients, PCR and Metavir scores for group (1) patients, and triphasic CT abdomen and AFP for Group (3) patients. B2M levels were measured in serum with a fully-automated IMX system. Results: The mean serum B2M level of Group (1) was $4.25{\pm}1.48{\mu}g/ml$., Group (2) was $7.48{\pm}3.04$, Group (3) was $6.62{\pm}2.49$ and Group (4) was $1.62{\pm}0.63$. Serum B2M levels were significantly higher in diseased than control group (p<0.01) being significantly higher in cirrhosis ($7.48{\pm}3.04$) and HCC groups ($6.62{\pm}2.49$) than the HCV group ($4.25{\pm}1.48$) (p<0.01). There was a significant correlation between B2M Level and ALK, total and direct bilirubin and INR (p<0.05), and a significant inverse correlation between B2M level and albumin, total proteins, HB andWBCS values (p<0.05). There was no significant correlation between B2M level and viral load or Metavir score, largest tumour size or AFP (p>0.05). The best B2M cut-off for HCV diagnosis was 2.6 with a sensitivity of 100%, a specificity of 92%, a positive predictive value (PPV) of 97% and a negative predictive value (NPV) of 100%. The best B2M cut-off for HCC diagnosis was 4.55 which yielded sensitivity, specificity, positive predictive value, negative predictive values of 74%, 62%, 39.5, 87.8% respectively (p-value <0.01) while best cut-off for cirrhosis was 4.9, with sensitivity 74 % and specificity 74%.The sensitivity for HCC diagnosis increased upon B2M and AFP combined estimation to 91%, specificity to 79%, NPV to 95% and accuracy to 83%. Conclusions: Serum B2M level is elevated in HCV related chronic liver diseases and may be used as a marker for HCV disease progression towards cirrhosis and carcinoma.

Improved Diagnostic Accuracy in Characterization of Adnexal Masses by Detection of Choline Peak Using 1H MR Spectroscopy in Comparison to Internal Reference at 3 Tesla

  • Malek, Mahrooz;Pourashraf, Maryam;Gilani, Mitra Modares;Gity, Masoumeh
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.12
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    • pp.5085-5088
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    • 2015
  • Background: The aim of this study was to assess the role of the presence of a choline peak in 3 Tesla 1H magnetic resonance spectroscopy (MRS) for differentiating benign from malignant adnexal masses. Materials and Methods: A total of 46 adnexal masses (23 malignant and 23 benign) underwent 1H MRS study prior to surgery to assess the presence of choline peak. Results: A choline peak was detected in 16 malignant masses (69.5%) and was absent in the other 7 (30.5%). A choline peak was only detected in 6 (26%) of the benign adnexal masses. The presence of an MRS choline peak had a sensitivity of 69.5%, a specificity of 74%, a positive predictive value (PPV) of 72.7%, and a negative predictive value (NPV) of 71% for diagnosing malignant adnexal masses. A significant difference between the frequency of mean choline peaks in benign and malignant adnexal masses was observed (P value < 0.01). Conclusions: A 1H MRS choline peak is seen in malignant adnexal masses more frequently than the benign masses, and may be helpful for diagnosing malignant adnexal masses.

Roles of Neutrophil/Lymphocyte and Platelet/Lymphocyte Ratios in the Early Diagnosis of Malignant Ovarian Masses

  • Yildirim, Mem Arjen;Seckin, Kerem Doga;Togrul, Cihan;Baser, Eralp;Karsli, Mehmet Fatih;Gungor, Tayfun;Gulerman, Hacer Cavidan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6881-6885
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    • 2014
  • Background: The present study aimed to investigate the utility and importance of the various parameters of complete blood count panel for benign-malignant differentiation of adnexal masses. Materials and Methods: This retrospective study involved 316 patients with documented benign and 253 patients with malignant adnexal masses who underwent primary surgical treatment at a tertiary referral center. Prior to the study, all benign and malignant cases were compared within their own groups and then the benign and malignant cases were compared to each other. For all cases, cut-off, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), neutrophil, lymphocyte, platelet and CA-125 parameters, and the results were compared in regards to the groups. Results: NLR, PLR, neutrophil, CA-125, and platelet values were higher in the malignant compared to the benign cases (p<0.01). The lymphocyte value was lower in the malignant cases (p<0.01). No significant differences were found for basophils and eosinophils (p > 0.05). For CA-125, the sensitivity, specificity, PPV and NPV for all cases were 78%, 62%, 62% and 78%, respectively. For NLR, they were 65.6%, 72.1%, 65.3%, and 72.3%, and for PLR, 48%, 81%, 67%, and 66%. Additionally, the sensitivity and specificity were 55% and 77% for CA-125, 66% and 58% for NLR, and 61% and 58% for PLR in early malignant cases. Conclusions: NLR and PLR appear to be useful methods that can be applied together with CA-125 due to the relatively high sensitivity values for the malign-benign differentiation of ovarian masses. Although the specificity of these parameters is lower than CA-125, especially in cases with early malignant ovarian pathology, their sensitivity being higher is promising for the early diagnosis of ovarian cancer. It can be used to detect ovarian malignancies in the early stages, and it will increase the treatment options and improve survival rates.

Agreement between Colposcopic Diagnosis and Cervical Pathology: Siriraj Hospital Experience

  • Tatiyachonwiphut, Molpen;Jaishuen, Atthapon;Sangkarat, Suthi;Laiwejpithaya, Somsak;Wongtiraporn, Weerasak;Inthasorn, Perapong;Viriyapak, Boonlert;Warnnissorn, Malee
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.1
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    • pp.423-426
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    • 2014
  • Aim: To evaluate the agreement between colposcopic diagnosis and cervical pathology a retrospective chart review was performed. Materials and Methods: This study included 437 patients who underwent colposcopy and cervical biopsy or conization at Siriraj Hospital from October 2010 - December 2012. The patient clinical characteristics, cervical cytology results, colposcopic diagnoses, cervical pathology results were recorded and correlations between variables were analyzed. Results: Agreement of colposcopic diagnosis and cervical pathology was matched in 253 patients (57.9%). The strength of agreement with weighted Kappa statistic was 0.494 (p<0.001). Colposcopic diagnoses more often overestimated (31.1%) than underestimated (11%) the cervical pathology. Agreement of colposcopic diagnosis and cervical pathology within 1 grade was found in 411 patients (94.1%). Positive predictive value (PPV) of high grade colposcopy or more was 75.5%, whereas the negative predictive value (NPV) of insignificant and low grade colposcopy was 83.8%. False positives of high grade colposcopy or more were 21%. False negatives of insignificant or low grade colposcopy were 19.1%. Conclusions: Strength of agreement between colposcopic diagnosis and cervical pathology was found to be only moderate. A biopsy at colposcopy should be performed at a gold standard level to detect high grade lesions.

Fate of pulmonary nodules detected by computer-aided diagnosis and physician review on the computed tomography simulation images for hepatocellular carcinoma

  • Park, Hyojung;Kim, Jin-Sung;Park, Hee Chul;Oh, Dongryul
    • Radiation Oncology Journal
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    • v.32 no.3
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    • pp.116-124
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    • 2014
  • Purpose: To investigate the frequency and clinical significance of detected incidental lung nodules found on computed tomography (CT) simulation images for hepatocellular carcinoma (HCC) using computer-aided diagnosis (CAD) and a physician review. Materials and Methods: Sixty-seven treatment-$na{\ddot{i}}ve$ HCC patients treated with transcatheter arterial chemoembolization and radiotherapy (RT) were included for the study. Portal phase of simulation CT images was used for CAD analysis and a physician review for lung nodule detection. For automated nodule detection, a commercially available CAD system was used. To assess the performance of lung nodule detection for lung metastasis, the sensitivity, negative predictive value (NPV), and positive predictive value (PPV) were calculated. Results: Forty-six patients had incidental nodules detected by CAD with a total of 109 nodules. Only 20 (18.3%) nodules were considered to be significant nodules by a physician review. The number of significant nodules detected by both of CAD or a physician review was 24 in 9 patients. Lung metastases developed in 11 of 46 patients who had any type of nodule. The sensitivities were 58.3% and 100% based on patient number and on the number of nodules, respectively. The NPVs were 91.4% and 100%, respectively. And the PPVs were 77.8% and 91.7%, respectively. Conclusion: Incidental detection of metastatic nodules was not an uncommon event. From our study, CAD could be applied to CT simulation images allowing for an increase in detection of metastatic nodules.

Predictive Values of Early Rest/24 Hour Delay T1-201 Perfusion SPECT for Wall Motion Improvement in Patients with Acute Myocardial Infarction After Reperfusion (급성 심근 경색 환자에서 재관류 후 조기에 시행한 휴식/24시간 지연 T1-201 심근 SPECT의 심근벽 운동 호전 예측능)

  • Hyun, In-Young;Kwan, June
    • The Korean Journal of Nuclear Medicine
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    • v.32 no.3
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    • pp.259-265
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    • 1998
  • Purpose: We studied early rest/24 hour delay T1-201 perfusion SPECT for prediction of wall motion improvement after reperfusion in patients with acute myocardial infarction. Materials and Methods: Among 17 patients (male/female= 11/6, age: $59{\pm}13$) with acute myocardial infarction, 15 patients were treated with percutaneous transcoronary angioplasty (direct:2, delay: 11) and intravenous urokinase (2). Spontaneous resolution occurred in infarct-related arteries of 2 patients. We confirmed TIMI 3 flow of infarct-related artery after reperfusion in all patients with coronary angiography. We performed rest T1-201 perfusion SPECT less then 6 hours after reperfusion and delay T1-201 perfusion SPECT next day. T1-201 uptake was visually graded as 4 point score from normal (0) to severe defect (3). Rest T1-201 uptake ${\le}2$ or combination of rest T1-201 uptake ${\le}2$ or late reversibility were considered to be viable. Myocardial wall motion was graded as 5 point score from normal (1) to dyskinesia (5). Myocardial wall motion was considered to be improved when a segment showed an improvement ${\ge} 1$ grade in follow up echo compared with the baseline values. Results: Among 98 segments with wall motion abnormality, the severity of myocardial wall motion decrease was as follow: mild hypokinesia: 18/98 (18%), severe hypokinesia: 28/98 (29%), akinesia: 51/98 (52%), dyskinesia: 1/98 (1%). The wall motion improved in 85%. Redistribution (13%), and reverse redistribution (4%) were observed in 24 hour delay SPECT. Positive predictive value (PPV) and negative predictive value (NPV) of combination of late reversibility and rest T1-201 uptake were 99%, and 54%. PPV and NPV of rest T1-201 uptake were 100% and 52% respectively. Predictive values of combination of rest T1-201 uptake and late reversibility were not significantly different compared with predictive values of rest T1-201 uptake only. Conclusion: We conclude that early T1-201 perfusion SPECT predict myocardial wall motion improvement with excellent positive but relatively low negative predictive values in patients with acute myocardial infarction after reperfusion.

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Ovarian Masses: Is Multi-detector Computed Tomography a Reliable Imaging Modality?

  • Khattak, Yasir Jamil;Hafeez, Saima;Alam, Tariq;Beg, Madiha;Awais, Mohammad;Masroor, Imrana
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.4
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    • pp.2627-2630
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    • 2013
  • Background: Ovarian cancer continues to pose a major challenge to physicians and radiologists. It is the third most common gynecologic malignancy and estimated to be fifth leading cancer cause of death in women, constituting 23% of all gynecological malignancies. Multi-detector computed tomography (MDCT) appears to offer an excellent modality in diagnosing ovarian cancer based on combination of its availability, meticulous technique, efficacy and familiarity of radiologists and physicians. The aim of this study was to compute sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of 64-slice MDCT in classifying ovarian masses; 95% confidence intervals were reported. Materials and Methods: We prospectively designed a cross-sectional analytical study to collect data from July 2010 to August 2011 from a tertiary care hospital in Karachi, Pakistan. A sample of 105 women aged between 15-80 years referred for 64-MDCT of abdomen and pelvis with clinical suspicion of malignant ovarian cancer, irrespective of stage of disease, were enrolled by non-probability purposive sampling. All patients who were already known cases of histologically proven ovarian carcinoma and having some contraindication to radiation or iodinated contrast media were excluded. Results: Our prospective study reports sensitivity, specificity; positive and negative predictive values with 95%CI and accuracy were computed. Kappa was calculated to report agreement among the two radiologists. For reader A, MDCT was found to have 92% (0.83, 0.97) sensitivity and 86.7% (0.68, 0.96) specificity, while PPV and NPV were 94.5% (0.86, 0.98) and 86.7% (0.63, 0.92), respectively. Accuracy reported by reader A was 90.5%. For reader B, sensitivity, specificity, PPV and NPV were 94.6% (0.86, 0.98) 90% (0.72, 0.97) 96% (0.88, 0.99) and 87.1% (0.69, 0.95) respectively. Accuracy computed by reader B was 93.3%. Excellent agreement was found between the two radiologists with a significant kappa value of 0.887. Conclusion: Based on our study results, we conclude MDCT is a reliable imaging modality in diagnosis of ovarian masses accurately with insignificant interobserver variability.